US20120222601A1 - Method and device for absorbing initial force in a thread delivery device - Google Patents
Method and device for absorbing initial force in a thread delivery device Download PDFInfo
- Publication number
- US20120222601A1 US20120222601A1 US13/041,281 US201113041281A US2012222601A1 US 20120222601 A1 US20120222601 A1 US 20120222601A1 US 201113041281 A US201113041281 A US 201113041281A US 2012222601 A1 US2012222601 A1 US 2012222601A1
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- United States
- Prior art keywords
- thread
- needle
- spool
- force
- drive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05C—EMBROIDERING; TUFTING
- D05C11/00—Devices for guiding, feeding, handling, or treating the threads in embroidering machines; Machine needles; Operating or control mechanisms therefor
- D05C11/08—Thread-tensioning arrangements
- D05C11/10—Guides, e.g. resilient
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H59/00—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators
- B65H59/10—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators by devices acting on running material and not associated with supply or take-up devices
- B65H59/36—Floating elements compensating for irregularities in supply or take-up of material
-
- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05B—SEWING
- D05B47/00—Needle-thread tensioning devices; Applications of tensometers
- D05B47/04—Automatically-controlled tensioning devices
-
- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05B—SEWING
- D05B53/00—Thread- or cord-laying mechanisms; Thread fingers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2701/00—Handled material; Storage means
- B65H2701/30—Handled filamentary material
- B65H2701/31—Textiles threads or artificial strands of filaments
Definitions
- the present invention relates to a device and method for absorbing some of the initial force/energy exerted by a thread delivery device. Such a device and method are particularly useful when applied to sewing and embroidery machines. However, this device and method are equally applicable to any similar type of feeding device (e.g., a device that feeds string, rope, chain, etc.).
- Prior art sewing and embroidery machines use a needle or some other feed device to pull thread from a spool so that the thread can be delivered to, and penetrated through, a material that is to be stitched. These devices transfer most of the initial force exerted on the thread by the feeding device directly to the thread spool (with some force obviously being lost due to friction).
- variable thread tension With such a variable thread tension, it is difficult to ensure proper tension in the thread stitches. Thus, the quality of the stitches made may be adversely affected.
- this variable thread tension can result in thread slippage at the point where the thread feeding device engages with the thread. If such thread slippage occurs, then the actual amount of thread that is fed is less than the intended amount. Thus could result in an inadequate amount of thread being provided for the current stitch. In this case, the additional thread needed for the stitch would be pulled from the previous stitch, which could negatively affect the stitch quality. In fact, if too much additional thread is pulled from the prior stitch, then the prior stitch could be pulled completely out of the workpiece. This presents a significant problem.
- Spool over spinning only adds to these problems. More specifically, spool over-spinning causes more thread to be pulled from the spool than is intended, which often results in the over-pulled thread causing a mechanical jam in the sewing or embroidery machine. In addition, even if the over-pulled thread does not cause a mechanical jam, the over-pulled thread presents less resistance the next time the feeding device attempts to pull the thread, since the rotational resistance of the spool does not need to be overcome in order to remove the over-pulled thread from the spool. This only serves to exacerbate the variable thread tensioning problems discussed above.
- a force deflection device such as a spring
- a sewing machine including an embroidery machine
- a material feeding device which includes material wrapped around a spool, the spool rotating around an axis.
- a material feeding mechanism feeds the material in a feeding direction, thereby unraveling the material from the spool.
- a force deflection device is arranged between the spool and the material feeding mechanism, and is connected to the material. The force deflection device is configured to as to deform physically when the material feeding mechanism applies an initial feeding force to the material.
- a method of feeding a material from a spool involves using a material wrapped around a spool (which rotates around an axis). An initial feeding force is applied to the material so as to unravel the material from the spool. A force deflection device, which is connected to the material, is physically deformed and absorbs a portion of the initial feeding force before the initial feeding force is transferred to the thread on the spool.
- a machine containing multiple cartridges installed concurrently promises greatly enhanced utility and convenience by reducing the number of user interventions per finished workpiece.
- a machine with capability to hold and sequentially operate four cartridges can reduce the number of user interventions required to produce an eight-color pattern from seven to just one.
- Such a machine includes embodiments that: reduce the quantity and mass of moving parts per needle as compared with prior art designs, such that increased power supply is not required; and incorporate a means for selectively engaging the operation of a desired cartridge through cooperative employment of existing machine mechanisms.
- FIGS. 1A-1C show a sewing apparatus.
- FIG. 1D shows a cutaway perspective view of an upper body and an embroidery frame of the sewing apparatus.
- FIGS. 2A and 2B show, respectively, a cutaway perspective view and plan view of the base portion of the sewing apparatus showing an embroidery frame driving mechanism.
- FIG. 3 shows profile views of frame engagement mechanism arranged as a schematic flow showing the operation sequence thereof.
- FIGS. 4A-4C show a thread feed cartridge selection and engagement mechanism.
- FIGS. 5A-5D show embodiments of a thread feed mechanism.
- FIGS. 6A-6E show embodiments of a detection device.
- FIG. 7 shows a controller for the sewing apparatus.
- FIGS. 8A and 8B show, respectively, how a fixed thread position is maintained relative to the needle tip during downward motion of the needle to make a stitch, and how a static position of the thread relative to the workpiece is maintained during the upward motion of the needle after a stitch has been made.
- FIG. 9 shows various parameters required by the controller in order to determine a first amount of thread needed to make a stitch.
- FIG. 10 shows a top side view of a portion of the workpiece in which one stitch has been made at location X 1 ,Y 1 and a next stitch has been made at location X 2 ,Y 2 .
- FIG. 11 shows a situation where the desired loop length is smaller than the height of a slack position of the needle.
- FIG. 12 shows how, between needle cycles, the needle is positioned at a slack position during the XY movement of the workpiece 18 .
- FIGS. 13A-13E show the needle cycles through up/down movements and the workpiece moves in XY directions to form the stitches.
- a single device, article or other product When a single device, article or other product is described herein, more than one device/article (whether or not they cooperate) may alternatively be used in place of the single device/article that is described. Accordingly, the functionality that is described as being possessed by a device may alternatively be possessed by more than one device/article (whether or not they cooperate). Similarly, where more than one device, article or other product is described herein (whether or not they cooperate), a single device/article may alternatively be used in place of the more than one device or article that is described. Accordingly, the various functionality that is described as being possessed by more than one device or article may alternatively be possessed by a single device/article.
- the sewing apparatus body 2 includes a casing 10 , an embroidery frame driving mechanism 9 that moves the embroidery frame 11 having the work cloth 18 in a horizontal plane with respect to the hollow needle 102 while the embroidery frame 11 is held by a carriage 9 .
- the body 2 also comprises and a selective engagement mechanism (See FIGS. 4A-4C ) for selecting a cartridge 100 from the plurality of cartridges 100 a, 100 b, 100 c, 100 d.
- the casing 10 is a relatively small rectangular solid.
- the casing 10 may be 14 inches (356 mm) long, 9 1 ⁇ 2 (241 mm) inches wide and 5 1 ⁇ 2 inches (139 mm) high.
- the casing 10 contains main parts of the embroidery frame driving mechanism 9 and the cartridge driving mechanism 109 , and the selective engagement mechanism 200 .
- a slot 5 allows access of the embroidery frame 11 into the apparatus 1 for sewing during operation of the apparatus 1 .
- the slot 5 extends in a lateral direction along a front wall 10 c of the apparatus 1 , and is formed in a front wall 10 c between a base portion 2 b and a top portion 2 a of the apparatus 1 .
- the casing 10 is formed as a unitary body (as shown in FIG. 1A ) and the slit 5 is runs laterally along a front wall 10 c and partially down the side walls 10 b, 10 d of the casing 10 .
- the slit 5 is provided as to attach the embroidery frame 11 to an engagement mechanism 20 to engage the embroidery frame 11 to the embroidery frame driving mechanism 9 and to move the embroidery frame 11 in a horizontal plane.
- On the right side of the upper surface 10 a is a power switch 3 , and a start/stop switch 4 that starts and stops the sewing.
- Upper surfaces of the power switch 3 and the start/stop switch 4 are positioned at the same or a slightly lower level than the upper surface of the upper wall 10 a.
- FIG. 1D shows a cutaway perspective view of the upper body 2 a and an embroidery frame 11 , in an embodiment where the upper body 2 a forms a cover portion of the sewing machine 1 .
- the apparatus 1 comprises a removable embroidery frame 11 , a body 2 of the apparatus, and a frame and drive engagement mechanism 50 (See FIG. 3 ) for engaging the frame to a frame driving mechanism 9 .
- the apparatus 1 further comprises at least one mating alignment feature 6 , 12 for engaging the frame 11 with the apparatus, wherein the mating alignment feature allows engagement of the embroidery frame to the apparatus where the frame and drive engagement mechanism 50 are at least partially obscured.
- the mating alignment feature further comprises a frame alignment feature 12 on the embroidery frame 11 and a body mating alignment feature 6 corresponding to the frame alignment feature.
- a raised alignment feature 12 is added to the leading edge of the embroidery hoop 11 where the leading edge is to be inserted into the engagement mechanism 20 within the embroidery apparatus 1 .
- a cutout 6 of a shape corresponding to the raised feature 12 on the embroidery frame 11 allows clearance through the top portion 10 a of the embroidery machine 1 .
- the cutout 6 is positioned on the front face 10 c of the top portion 2 a to facilitate direct access to the frame and drive engagement mechanism 50 (See FIG. 3 ) within the machine.
- the cutout 6 has a negative space profile that corresponds to the shape of the raised alignment feature 12 .
- the frame could be made in an embodiment (not shown) such that the cutout feature 6 is on the frame and the raised feature 12 is on the body 2 a (e.g., via a groove cutout feature 6 and raised feature 12 comprising guide element 7 formed as a notched rail 12 on the underside of the upper body 2 a ).
- the apparatus further comprises a guide element 7 , shown as a guide channel 7 configured such that the embroidery frame 11 can be moved through the body to a point of engagement with the frame and drive engagement mechanism 50 ( FIG. 3 ).
- a guide channel 7 is provided within the top portion 2 b, leading from the cutout opening 6 of the upper body portion 2 a to the point of engagement with the engagement mechanism 20 .
- the guide channel comprises sloped rail elements 7 a, 7 b that correspond to the shape of the cutout 6 .
- the raised alignment feature 12 of the embroidery hoop 11 is larger than the slot 5 , through which the frame 11 otherwise passes into the machine 1 during both frame 11 insertion and machine 1 operation. Accordingly, this raised feature 12 effectively prevents insertion of the embroidery frame 11 into the machine 1 to the degree that the frame 11 may be lost accidentally from the reach of the operator's finger grip.
- the mating alignment features 6 , 12 of the upper body 2 b and the frame 11 of the machine cover are chosen to be of a distinct and easily recognizable shape, thereby facilitating intuitive recognition of the insertion direction.
- the raised feature 12 and the cutout 6 both take a similar polygonal form as shown in FIG. 1D
- other such intuitively recognizable shapes could be chosen (such as semi-circular, square, or even a whimsical design element such as a clover, a distinctive symbol or mark, or an animated character's profile).
- a latching mechanism 14 for the engagement frame 11 is further operated by intuitive, tactile push/pull engagement and disengagement of the frame 11 , which is described in more detail below (See FIG. 3 ).
- a latching mechanism 14 for the engagement frame 11 is further operated by intuitive, tactile push/pi 11 engagement and disengagement of the engagement frame 11 once aligned, using the intuitive mating alignment features 6 , 12 as shown in FIG. 1D .
- the latching mechanism 44 engages with a frame driving mechanism 9 for moving the workpiece 18 in the horizontal plane within the embroidery machine 1 .
- the carriage 9 has an engagement portion 16 that can engage/disengage an installation portion 14 of the embroidery frame 11 thereto/therefrom.
- FIGS. 2A and 2B are respectively a cutaway perspective view and plan view of the base portion 2 b of the sewing apparatus 1 showing the embroidery frame driving mechanism 9 .
- An exemplary embroidery frame driving mechanism which can be employed in the embodiments of the invention described herein is also shown in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein.
- the embroidery frame driving mechanism 9 includes the carriage 8 to which the embroidery frame 11 is detachably attached, an X-axis direction driving mechanism 20 that drives the carriage 8 in an X direction (the left-right direction as shown) within a horizontal plane, and a Y-axis direction driving mechanism 25 that drives the carriage 8 in a Y direction (the front and rear direction as shown) perpendicular, within the horizontal plane, to the X direction.
- the X-axis direction driving mechanism 20 includes a moving frame 24 , an X-axis slider 22 attached to a X-axis drive belt 21 , and an X-axis guide shaft 23 .
- the driving mechanism 20 is operatively connected to a drive motor 29 .
- the moving frame 21 is rectangular moves with a Y-axis slider 28 .
- the guide shaft 23 is supported at its ends by side walls of the moving frame 21 .
- the Y-axis direction driving mechanism 25 includes the Y-axis slider 28 attached to a Y-axis belt drive belt 27 and a Y-axis guide shaft 26 .
- the Y-axis direction driving mechanism 25 is also operatively connected to a drive motor 29 .
- the Y-axis slider 28 is disposed under and attached to the X-axis direction driving mechanism 20 , such that the moving frame 21 moves with the Y-axis slider 28 .
- the engagement mechanism includes a fixed guide 15 , comprising a channel 17 formed by at least one guide member 15 and a latch mechanism 14 configured to engage a frame catch member 16 on the frame to the frame driving mechanism 9 .
- the channel 17 is configured to position the latch mechanism 14 and the catch member 16 such that the latch mechanism 14 engages and disengages the frame catch member 16 at a fixed location 19 .
- a controller 70 controls the frame driving mechanism 9 , and is configured to position the latch mechanism at the fixed location 16 .
- the channel 17 has a drive engagement side 29 and a frame engagement side 28 .
- the controller 70 of the sewing apparatus 1 has a computer 71 , which includes a CPU 71 a, a ROM 71 b, a RAM 71 c, an input/output interface 71 d, and an input/output terminal 71 e.
- the CPU 71 a, the ROM 71 b, the RAM 71 c, the input/output interface 71 d, and the input/output terminal 71 e are operatively connected to each other, as for example via a bus.
- the input/output interface 71 d is connected with a drive circuit 20 a for the pulse motor 20 x of the X-axis direction driving mechanism 20 , a drive circuit 25 a for the pulse motor 25 y of the Y-axis direction driving mechanism 25 , a drive circuit 24 a for the drive motor 24 of the thread feed and engagement driving mechanism 30 , the power switch, and the start/stop switch 4 .
- a drive circuit 20 a for the pulse motor 20 x of the X-axis direction driving mechanism 20 a drive circuit 25 a for the pulse motor 25 y of the Y-axis direction driving mechanism 25 , a drive circuit 24 a for the drive motor 24 of the thread feed and engagement driving mechanism 30 , the power switch, and the start/stop switch 4 .
- Exemplary controller and computer systems that can be used in conjunction with the present invention are described in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein.
- the controller 70 includes a drive 72 capable of reading and writing instructions from memory 73 , including internal memory or memory from a stored memory device 73 .
- the drive 72 can be any device configured to read memory such as flash drives, CDs or DVDs, cartridges, memory cards, and other like devices, and includes hardware for interfacing therewith.
- the stored memory device can be an external storage medium, such as a memory cartridge, memory card, flash drive, CD or DVD, or other like device.
- the stored memory device can even comprise remote storage 73 b transmitted over WAN or LAN networks, including those such as in cloud computing and storage systems.
- the memory 73 stores various sewing data and programs, so that the sewing data and the programs are readable by the computer 71 . Similarly, the control programs, the control signals, and the data may be distributed worldwide via the Internet.
- an embroidery pattern can be formed on the workpiece 18 by controlling the embroidery frame driving mechanism 29 (the X-axis direction driving mechanism 20 and the Y-axis direction driving mechanism 25 ) and the thread feed driving mechanism 100 by the controller 70 based on the sewing data.
- a control program for sewing is stored in the ROM 71 b.
- the memory storage 73 stores various kinds of embroidery patterns, pattern data of various kinds for prestored embroidery patterns, and a pattern selection control program for selecting a desired embroidery pattern from the various kinds of embroidery patterns.
- the memory storage 73 also can include a pattern edit control program for editing (e.g., enlargement, reduction, unification, reversal) a selected embroidery pattern, and a display control program for displaying an embroidery pattern for selecting and setting on a display (not shown).
- a flash card 73 connectable to the flash card connector, can store pattern data of a selected/edited embroidery pattern.
- FIG. 3 shows profile views arranged as a schematic flow showing the operation sequence designed to position the latching mechanism 14 at a specific position of engagement and disengagement when the installation or removal of the embroidery hoop 11 is indicated.
- the controller 70 includes machine software and hardware (See FIG. 7 ) that controls this movement.
- the latching mechanism 14 is designed to allow manual disengagement of the embroidery hoop 11 . In this way, accidental disengagement of the hoop from the machine during other modes of operation can be prevented.
- the latch mechanism 14 is moved into an engagement position against a fixed guide member 15 .
- the engagement position is a channel 17 formed by two fixed guide members 15 a , 15 b.
- the controller 70 moves the drive-side 29 frame engagement mechanism 14 to the fixed guide members 15 a, 15 b from the drive engagement side 29 to a frame engagement position 19 .
- the catch member 16 on the frame engages the latch mechanism 14 at the engagement position 19 .
- the one guide member 15 b is shorter than the other guide member 15 a. This allows the latch mechanism 14 to move into a stationary engagement/disengagement position by abutting the shorter guide member 15 b, and sliding underneath the longer guide member such that the latch protrusion 14 a has a spring tension against the upper guide member 15 a.
- the catch member 16 of the drive engagement mechanism includes an opening 16 a, and is positioned into an engagement position 19 from the frame engagement side 28 of the fixed guide member.
- the hoop or frame catch member 16 is separately guided into the channel 17 from the frame entry end 28 , moving the catch member opening 16 a along the channel 17 formed by the fixed guide members 15 a, 15 b to the engagement position such that the spring loaded latch mechanism 14 is displaced under the catch member 16 until the catch member opening 16 a reaches the engagement position 19 .
- the protrusion 14 a of the stationary latch mechanism 14 meets the frame catch member 16 and engages a slot or opening 16 a of the catch.
- the latch protrusion 14 a includes at least one beveled edge 14 b, which is adapted to allow the fixed guide member 15 a and catch member 16 to displace the latch mechanism 14 when the latch mechanism 14 is moved against the fixed guide member 15 a or the catch member 16 .
- the fixed guide member 15 a and the catch member 16 respectively, have reciprocally sloped bevels 16 b, 15 c, which facilitate the displacement of the latch mechanism 14 when moved against the fixed guide member 15 or the catch member 16 .
- the frame catch member 16 is placed at a position where a user can no longer move the frame catch member 16 further into the sewing apparatus, as for example, against a stop (not shown).
- the protrusion 14 a of the latch mechanism 14 partially engages the catch slot 16 a, up to the point where the latch protrusion 15 a abuts the upper fixed guide member 15 a.
- the frame catch member 16 and latch mechanism 14 are moved into the machine workspace by the machine software (not shown). It will be noted that as the latch mechanism 14 moves the frame into the sewing apparatus, the latch fully engages the catch member as it passes out of the guide member 15 .
- Disengagement and removal of the embroidery frame 11 is accomplished by reversing steps 200 - 230 .
- the latch protrusion 14 includes the at least one beveled edge 14 b, which allows the fixed guide member 15 a to again displace the latch mechanism 14 when the latch mechanism 14 is moved against the fixed guide member 15 a (as in going from step 230 to step 220 ).
- the fixed guide member's sloped bevel 15 c facilitates the displacement of the latch mechanism 14 when moved against the fixed guide member 15 .
- the sewing apparatus 1 can be configured to have a plurality of thread feed mechanisms, shown as removable cartridges 100 a, 100 b, 100 c, 100 d. As shown in FIGS. 1A-1C , in one embodiment the sewing apparatus 1 comprises 4 cartridges. However, the apparatus as described herein could be adapted to include any number of cartridges 100 n . Each cartridge could, for example, have a different colored thread, thereby allowing a preprogrammed embroidery pattern utilizing many different colors to be completed with fewer runs of the apparatus 1 . For example a preprogrammed pattern with 4 colors could be completed in one run of the apparatus configured to simultaneously include 4 cartridges 100 a, 100 b, 100 c, 100 d each with threads of the corresponding colored threads. Because the cartridges 100 a , 100 b, 100 c, 100 d are each replaceable, a preprogrammed embroidery pattern including 8 or less colors could be completed in two runs on the embodiment including 4 cartridges.
- FIGS. 4A-4C show a thread feed cartridge selection and engagement mechanism 30 which is operatively connected to the embroidery frame driving mechanism 9 .
- the sewing apparatus 1 comprising a fixed cartridge 100 and moving needle 102 (See FIGS. 5A-B ) can reduce the power consumed in stitching the workpiece 18 .
- the current embodiment moves only the needle 102 and related mechanisms of low-inertia design. This is accomplished by means of a gear train (described herein) that selectively transmits power from a drive motor 24 to a rack-mounted needle 102 within the cartridge 100 .
- the reduced inertia of moving parts requires less energy to achieve the required accelerations in opposite directions on each stitching cycle.
- FIG. 4A shows one embodiment of a system and method for a thread feed selection and engagement mechanism 30 .
- the sewing apparatus 1 comprises a drive mechanism 24 , a thread feed mechanism comprising a removable cartridge 100 , and a needle engagement mechanism 104 for engaging the thread feed mechanism.
- the drive mechanism comprises a drive motor 24 configured to transmit power from the drive motor 24 to the needle engagement mechanism, such that the drive motor 24 drives a needle within the cartridge without moving the entire cartridge.
- the thread feed selection and engagement mechanism 30 in the embodiment includes a spur gear transmission 30 , comprising a movable output drive gear 33 capable of selective engagement with one of several installed cartridges 100 a, 100 b , . . . 100 n, such that a single drive motor 24 can be employed to select and drive each cartridge in the apparatus 1 when a plurality of cartridges 100 a, 100 b, . . . 100 n are installed.
- a spur gear transmission 30 comprising a movable output drive gear 33 capable of selective engagement with one of several installed cartridges 100 a, 100 b , . . . 100 n, such that a single drive motor 24 can be employed to select and drive each cartridge in the apparatus 1 when a plurality of cartridges 100 a, 100 b, . . . 100 n are installed.
- the selective engagement mechanism 30 is actuated by a complimentary function of the X-Y embroidery frame driving mechanism 9 and the controller 70 therefor, as described herein.
- the drive mechanism 9 and controller 70 are of a design otherwise commonly employed in embroidery machines as known to those of ordinary skill in the art (such as that shown in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein).
- one exemplary advantage of the selective engagement mechanism 30 is that it can be configured to work in conjunction with an existing mechanism to add functionality thereto.
- the controller 71 and machine operating software 71 b, 71 c therefore, control the selective engagement mechanism 30 so as to arrange the selective engagement mechanism 30 to position a selector lever 31 at a predetermined location facilitating engagement from the Y-direction.
- This is followed by a sequence of coordinated movements of the selective engagement mechanism 30 in the X-Y directions, a first sweep of the selective engagement mechanism 30 intended to intercept and move a keyed drive gear mechanism 33 from any position on the drive shaft 32 to a predetermined position at the end of the sweep, and a second sweep of the selective engagement mechanism 30 in the opposite direction terminating so as to position the keyed drive gear mechanism 33 in the location of engagement with the drive mechanism 104 of the desired cartridge 100 .
- the drive shaft 32 is operatively connected to the drive motor 24 and at least one drive gear 33 positioned on the shaft.
- the drive motor can comprise a variable speed motor (e.g., a stepper motor).
- the drive gear 33 is configured such that it can slide from position to position on the shaft 32 .
- a drive shaft 32 comprises a physical configuration including, for example, a shaped cross section such that a keyed drive gear 33 of suitably matched cross section mounted thereon is constrained from rotating about and relative to the axis the shaft 32 , and remains free to slide parallel to the axis.
- Such configurations can be of a non round shape, but could also include a round cross-section with elements adapted to allow for driving the gear, such as a tab along the shaft 32 and a corresponding slot in a drive gear 33 .
- shafts and gears accomplishing this purpose are well known in the art, such as the cross-sectional shapes including shapes a D shape, a round shape, a non-round shape, a clover shape, a notched shape, a triangular shape, a square shape, a polygonal shape, and a rectilinear shape.
- a D-shaft and keyed drive gear is utilized.
- the drive shaft 32 is a D-shaft, and the keyed drive gear 33 is positioned thereon to facilitate secure placement and rotation of the drive gear 33 when the shaft 32 is rotated by the drive motor 24 .
- the range of X-direction movement of the keyed drive gear 33 on the keyed drive shaft 32 is limited to maintain positional control at all times and without risk of jamming, by ensuring that the selector can be safely positioned to begin each sweep outside the allowed range of drive gear movement on the shaft.
- the controller 70 is further configured to position the frame driving mechanism 9 (including the selector 31 in an area 45 outside of a work area 47 for the workpiece) to position the selector 31 to engage the drive gear 104 .
- the controller 70 is configured to position the selector outside the work area by moving the frame mechanism in the Y-direction. 25 .
- the controller 70 is further configured move the selector 31 in a first sweep to intercept and move the keyed drive gear 33 from any position on the drive shaft 32 to a predetermined position at the end of the sweep, and a second sweep in the opposite direction terminating so as to position the keyed drive gear 33 in the location of engagement (postitions 1-4) with the drive mechanism 104 of the thread feed mechanism 100 .
- the controller 70 is further configured to limit the range of X-direction movement of the drive gear 33 on the drive shaft 32 , such that the selector 31 is positioned to begin each sweep outside the limited range of drive gear 33 movement on the shaft 32 .
- the drive shaft 32 can also be physically configured to mechanically limit the range of X-direction movement of the drive gear 33 on the drive shaft 32 such that the selector 31 is positioned to begin each sweep outside the limited range of drive gear 33 movement on the shaft 32 .
- the drive shaft 32 can include a shaped cross-section such as a D-shaft.
- the drive gear 33 is keyed to the D-shaft and slideably positioned on the shaped cross-section to move along its axis, as described herein.
- the longitudinal cut of the cross-section on the shaft 32 can end in a position that limits the X-direction movement of the drive gear 33 on the drive shaft 32 , as, for example where the keyed D cross-section in the gear 33 abuts the shaft 32 at a point where the D-cut cross-section into the shaft 32 ends.
- the needle drive mechanism includes an idler gear 104 in a housing positioned to engage the drive gear and the thread feed mechanism 100 .
- a selector 31 is attached to the frame driving mechanism 9 .
- the selector 31 is configured to engage the drive gear 104 with the thread feed mechanism, and move the drive gear to any position (for example, 4 positions corresponding to the 4 cartridges 100 a - 100 d ).
- needle engagement mechanisms 104 a - 104 d are configured to engage the drive gear 33 to each of the cartridges.
- the controller 70 is configured to move the frame driving mechanism 9 to position the drive gear such that the drive gear engages the thread feed mechanism 100 .
- a reduction gear 40 and drive shaft 40 are provided between the drive shaft 32 and the drive motor 24 to control the torque delivered from the drive motor 24 .
- a locking mechanism 43 locks the drive gear 33 when the drive gear 33 engages a removable cartridge 100 .
- the locking mechanism 100 can include a detent on the drive shaft 32 to lock the drive gear 33 into a position wherein it can drive the needle engagement mechanism without slipping or sliding out of position.
- the detent is configured to lock the gear into position yet also allow the selector to move the gear between positions thread feed mechanisms 100 a - 100 d.
- the needle engagement mechanism can be configured to engage at least one thread feed mechanism, the thread feed mechanism comprising a removable cartridge. This can be accomplished by selecting at least one drive gear, and moving the drive gear to engage the at least one thread feed mechanism.
- the controller 70 moves the frame driving mechanism to position the drive gear such that the drive gear engages the thread feed mechanism 100 .
- the engagement mechanism 30 slides the at least one drive gear 33 to a needle engagement position, the drive gear being mounted on a shaft operatively connected to a drive motor 24 for driving the thread feed mechanism 100 .
- the frame 11 is positioned outside of a work area for a workpiece 18 when selecting and moving the drive gear 33 .
- the X-Y frame driving mechanism 9 moves the frame 11 in the Y-direction.
- the selector 31 is then positioned to engage a sequence of coordinated movements in the X-Y directions, so as to position the drive gear 33 such that the drive gear 33 engages a drive mechanism 104 of the thread feed mechanism.
- the positioning of the selector 11 includes moving the selector 11 in an X direction to a first drive gear 33 position (any of p- 1 to p- 4 ), moving the selector 11 in a Y direction to select the drive gear 33 , and then sliding the drive gear 33 in an X direction from the first drive gear position on the drive shaft to a second position on the drive shaft (any of p- 1 to p- 4 other than the first position), the second position being the location of engagement with the drive mechanism 104 of the thread feed mechanism 100 .
- the range of X-direction movement of the drive gear 33 on the drive shaft 32 is such that the selector 11 is positioned to begin each sweep outside the limited range of drive gear 33 movement on the shaft 32 .
- the drive gear 33 is locked when the drive gear 33 engages the thread feed mechanism 100 . Power is then transmitted from a drive mechanism 24 , for example a stepper motor, to the needle engagement mechanism 106 such that it drives a needle 102 within the cartridge 100 .
- the mechanism can drive the needle 102 without moving the entire cartridge 100 .
- the sewing apparatus 1 comprises a device configured to actively feed embroidery thread out of a cartridge 100 through a hollow needle 102 .
- One advantage is that a thread break at or near the needle tip is automatically overcome through normal operation of the sewing apparatus 1 .
- Other exemplary advantages include: (a) enabling automatic recovery of the stitching function in the case of thread breakage during embroidery; (b) eliminating any requirement for user adjustment or trimming of thread from the cartridge, prior to use or storage; and (c) enabling a complimentary function for thread cutting on the underside of the workpiece using a cutter assay (See FIG. 4B , 39 ) thereby reducing or eliminating the need for manual thread trimming at the start, finish or at “jump stitches” in the embroidered pattern.
- FIGS. 5A-B show embodiments of a thread feed mechanism including a cartridge 100 .
- FIG. 5B shows the embodiment of the cartridge 100 comprising a double-acting lever mechanism configured to alternately engage both moving and non-moving thread locks.
- a replaceable cartridge 100 contains a thread spool 103 and a pre-threaded hollow needle 102 , which are configured to be mounted within the sewing apparatus 1 .
- the replaceable cartridge 100 also includes mechanisms for independent needle and thread motion control.
- a rack slider 106 is mounted in the cartridge body 100 a, the rack slider 106 being constrained to allow only translation in the vertical axis.
- the rack slider 106 is operatively connected to the needle drive gear 104 .
- This drive gear 104 delivers intermittent rotary motion to the rack slider 106 , which receives and follows that motion.
- the needle drive gear 104 is ultimately driven by the drive motor 24 (embodied hereby as a stepper motor 24 which delivers intermittent rotary energy).
- the drive gear 104 can be a keyed or ridged gear adapted to engage ridges on the rack slider 106 .
- the rack slider 106 is configured to engage a thread control lever 108 , such that the thread control lever 108 is at first rotated against a stop 106 a, 106 b (shown in the embodiment as unitary with the rack slider 106 ) according to the direction of rack slider 106 motion, then further constrained to translation following the rack slider 106 over a remaining stroke length.
- a fulcrum 107 of the thread control lever 108 is fixed to a thread feed body 110 , such that the thread control lever 108 in a first stage movement first rotates about a pivot to engage at least one thread lock 114 (discussed below), and then causes translation of the thread feed body 110 in a second stage movement.
- Intermittent rotary motion of the drive gear 104 is received and followed by the rack slider 106 mounted in the cartridge body 100 a, the rack slider 106 being constrained to allow only translation in the vertical axis.
- the thread feed body 110 includes a constraining channel 111 for thread passage, and a lateral slot 112 through which the thread control lever 108 can engage thread lock 114 B, thereby preventing motion of the thread 101 through the channel 111 during downward motion only. It will be understood the thread control lever may also engage the thread lock by a hinged connection 114 B or such connection as to allow the thread control lever to engage the thread lock 114 B
- the thread feed body 110 receives both the needle 102 and an extension guide element (embodied as extension guide spring 115 ) fixed to the thread feed body 110 at opposite ends.
- extension guide spring 115 an extension guide element fixed to the thread feed body 110 at opposite ends.
- the thread 101 is passed through the extension guide spring 115 , which is fixed on the upper end of a receiving feature 116 on the cartridge body 100 .
- the extension guide spring acts to constrain the thread 101 at all times against significant bending, kinking, or looping within the passages formed through the cartridge body 100 a, extension guide spring 115 , and the constraining channel 111 B of the thread feed body 110 .
- the cartridge body further contains a lateral slot 112 A through which the thread control lever 108 may engage thread lock 114 A, thereby preventing motion the thread in a fixed channel 111 A (here shown in the fixed cartridge 100 a ) during upward motion only.
- the thread control lever may also engage the thread lock 114 A by a hinged connection, or by such connection as to allow the thread control lever to engage the thread lock 114 A.
- a cylindrical presser foot 118 surrounds and is coaxial with the needle 102 .
- the presser foot 118 is mounted on or otherwise operatively connected to the rack slider 106 , such that the presser foot 118 is configured to move with the rack slider 106 .
- the presser foot 118 is further controlled by a return spring 122 , which is positioned to maintain a position of full extension as against the presser foot 118 unless bearing against the workpiece 18 .
- the return spring 122 is shown as positioned between the presser foot 118 and the rack slider 106 .
- a second return spring 120 is positioned to maintain the rack slider 106 at the upper limit of travel, until overcome by force exerted on the rack slider 106 by the drive gear 104 .
- the compression return spring 122 is shown as positioned between the presser foot fixed cartridge 100 a and the rack slider 106 .
- the return springs are shown as a compression return springs, but each could be any spring chosen as appropriate, including extension springs, torsion springs, or other such springs as known to those of ordinary skill in the art.
- a thread lock arm 124 of the cartridge body 100 a is positioned to engage the thread control lever 108 and thread lock 114 B in the feed body 110 , such that the thread 101 cannot be freely withdrawn from the cartridge 100 when the needle is positioned at the upper limit of travel.
- thread 101 is positively advanced with the needle on each downward stroke of the needle 102 , and thread thus advanced is further constrained against return with the needle 102 on each upward (return) stroke.
- thread 101 is actively advanced from the open tip 102 A of the needle 102 by an amount nearly equal to the downward stroke length of each cycle.
- the cartridge 100 could be configured to allow a single thread lock 112 to both constrain the movement of the thread to follow the needle on the downstroke and constrain the thread to stay stationary as the needle moves on an upstroke (not shown).
- a mechanism arranged to adjustably control the stroke length also positively controls the advance of thread from the cartridge 100 through the needle tip 102 A.
- Such control in coordination with separate control of the lateral movement of an embroidery workpiece (not shown), enables the following exemplary functions and features:
- the thread feeding mechanism described above maintains a fixed thread position relative to the needle tip during downward motion of the needle to make a stitch (i.e. pulling thread 101 from the spool 103 ), since the lower thread lock 114 B engages the thread 101 when a stitch is made.
- the thread feeding mechanism maintains a static position of the thread 101 during the upward motion of the needle 102 after a stitch has been made (i.e.
- tensioning of the stitches is accomplished by control of the feeding of the appropriate amount of thread 101 through controlling the up and down motion of the needle 102 and the engagement and disengagement of the thread locks 114 (i.e., upper thread lock 114 A being disengaged and lower thread lock 114 B being engaged when needle 102 moves down; and upper thread lock 114 A being engaged and lower thread lock 114 B being disengaged when needle 102 moves up).
- This control is accomplished by variable determination of the top of the needle stroke and the bottom of the needle stroke, on a stitch by stitch basis.
- the controller 70 is configured to calculate a first amount of thread A T1 needed for a particular stitch by using the following formula:
- a T1 L S +L L ⁇ C 1 ;
- L S is the desired stitch length (i.e., the distance from one stitch anchoring XY position to the next stitch anchoring XY position in the current needle cycle);
- L L is the desired length of the loop formed on the underside of the workpiece 18 as measured from the top surface of the workpiece 18 (i.e., the amount of thread 101 needed for appropriate anchoring of the stitch in the backing material);
- C 1 is a small constant which is subtracted to ensure that the appropriate thread tension is provided between stitches.
- FIG. 10 shows a top side view of a portion of the workpiece 18 in which one stitch has been made at location X 1 , Y 1 , and a next stitch has been made at location X 2 ,Y 2 .
- the controller 70 often times must also be configured to calculate the desired stitch length L S based on the known desired movement of the workpiece 18 from one stitch location X 1 ,Y 1 , to the next stitch location X 2 ,Y 2 . In this case, the controller 70 is configured to calculate the desired stitch length L S by using the following formula:
- the desired loop length L L is smaller than the height H S of a slack position P S (discussed below with reference to FIGS. 11 and 12 ) of the needle 102 above the position P W of the top of the workpiece 18 to allow for movement of the workpiece 18 to the next stitch location.
- the amount of thread 101 needed to move the workpiece 18 from a first XY position to a second XY position will be more than the first amount of thread A T1 calculated by the controller 70 . If this is the case, only playing out the first amount of thread A T1 from the spool 103 will result some of the thread 101 being pulled out of the previous stitch.
- the first amount of thread A T1 calculated by the controller 70 may actually be less than the actual amount of thread A T required to form the next stitch without unduly weakening the previous stitch.
- the controller 70 is configured to calculate a second amount of thread A T2 needed for a particular stitch by using the following formula:
- a T2 [L S 2 +H S 2 ] 1/2 .
- the controller is configured to compare the first amount of thread A TI with the second amount of thread A T2 , and use the greater of the two amounts as the actual amount of thread A T which is to be played out from the spool 103 .
- the controller 70 determines that the second amount of thread A T2 should be used, the controller is configured to increase the length L L of next loop made (when the controller uses A T2 as the actual amount of thread A T needed to make the next stitch) by the following formula:
- L Lnew ( A T2 ⁇ L S )+ C 2 .
- L Lnew is the newly determined desired length L L of next loop
- C 2 is a small constant which is added to ensure that the appropriate thread tension is provided between stitches (the constant C 2 may be the same value as that of the constant C 1 , or it may be a different value from that of the constant C 1 ).
- the workpiece 18 is moved in XY dimensions relative to the needle 102 to provide the correct location for the next stitch.
- the needle 102 must be positioned a minimum distance above the top surface of the workpiece 18 to allow for workpiece 18 to move in XY dimensions without the tip of the needle 102 snagging on the workpiece 18 or the threads of previous stitches.
- This minimum distance is referred to as the slack position P S , and has been determined to generally be in the range of 1 mm to 4 mm. Accordingly, the slack position P S changes each time a new current position P of the top of the workpiece is determined (discussed below).
- the needle 102 Before the needle 102 can come to rest at the slack position P S so that the workpiece 18 can be moved, a minimum amount of thread 101 for making the next stitch must first be played out from the spool 103 .
- the lower thread lock 114 B disengages from the thread 101 and the upper thread lock 114 A then engages the thread 101 so as to prevent the thread 101 from moving while the needle 102 is removed from the workpiece 18 .
- the needle 102 is moved to a rest position P R above the top surface of the workpiece 18 .
- the controller 70 is configured to determine the rest position P R based, in part, on a signal received from a sensor 65 (described below in relation to FIGS. 6A-6D ). More specifically, the controller 70 receives a signal from the sensor 65 upon the downward stroke of the needle 102 indicating the vertical position P W1 of the top of the workpiece 18 . The controller then adds the amount of thread A T needed to the vertical position P W1 in order to obtain the rest position P R of the needle 102 . After the needle 102 is moved to the determined rest position P R , the needle 102 is then moved to the slack position P S (as shown in FIG. 13C ), pulling thread 101 from the spool 103 , so that the workpiece 18 can be moved in XY dimensions.
- the controller 70 is configured to calculate a second rest position P R2 , in such a situation, by the following formula:
- P R2 P S1 +[A T ⁇ ( P Rmax ⁇ P W1 )];
- P S1 is a slack position of the needle 102 above the current position P W1 of the top of the workpiece.
- P R2 P W1 +H S +[A T ⁇ ( P Rmax ⁇ P W1 )].
- P R2 P W1 +[A T ⁇ ( P Rmax ⁇ P S1 )].
- the controller is configured to repeat the above process as many times as is needed to play out the entire amount of thread needed for the next stitch.
- the needle 102 is brought to the slack position P S so that workpiece 18 may be moved in the desired XY directions.
- the needle 102 is then lowered through the workpiece 18 to the loop position P L corresponding to a distance below the current position P W2 of the top surface of the workpiece 18 equal to the current desired loop length L L .
- the controller 70 receives a signal from the sensor 65 upon the downward stroke of the needle 102 to form the second stitch, which indicates the current vertical position P W2 of the top of the workpiece 18 .
- a preferable desired length of each loop formed on the underside of the workpiece 18 had been found to range from 0.5 mm to 4 mm Accordingly, the controller 70 may be configured to take into account a desired loop length constant L LC when forming stitches.
- the controller may be configured to calculate the next first amount of thread A T1next needed for the next stitch by using the following formula:
- a T1next L S +L LC ⁇ C 1 ⁇ (2 ⁇ L Lnew ⁇ 2 ⁇ L LC ).
- a T2next [L S 2 +H S 2 ] 1/2 ⁇ (2 ⁇ L Lnew ⁇ 2 ⁇ L LC ).
- the controller is configured to compare the first amount of thread A T1next with the second amount of thread A T2next , and use the greater of the two amounts as the actual next amount of thread A T which is to be played out from the spool 103 .
- the controller 70 determines (1) that the second amount of thread A T2next should be used, the controller is configured to repeat the process for increasing the length L L of next loop made as described above (when the controller uses A T2next as the actual next amount of thread A T needed to make the next stitch).
- amount of thread used to make the loop of the prior stitch (originally at twice the loop length L Lnew ) will be reduced to be roughly equal to the amount of thread (2 ⁇ L LC ) needed to make a loop of the desired length L LC (i.e., an amount of thread to extend through the top surface of the workpiece 18 to the bottom of the loop of length L LC , and then to extend from the bottom of the loop of length L LC back up through the top surface of the workpiece 18 ).
- the up and down movements of the needle 102 are determined by controller 70 on a stitch-by-stitch basis, rather than being fixed as constant up and down movements to fixed top and bottom needle positions. This allows for greater control of the tensioning of each stitch, as well as greater control of the lengths of the thread loops created on the underside of the workpiece. Accordingly, a unique optimization of sewing stitch quality is able to be obtained.
- the various positions of the needle 102 are determined based on the tip of the needle. This is because this position of the needle also corresponds to the position at which the thread is attached to the needle in the shown embodiment (i.e., where the thread passes through a hollow needle).
- the up and down movements of a solid needle with a horizontal hole (e.g., an “eye”) through which the thread passes can clearly also be determined on a stitch-by-stitch basis as above described above described above.
- the various positions of the needle 102 would be determined based on the horizontal hole of the needle (e.g., the position of the “eye” of the needle).
- a further embodiment adds a force deflection device 300 to the thread path between the spool 103 , and the needle drive mechanism 301 (which includes the rack slider 106 , thread feed body 110 , and lower thread lock 114 B) and upper thread lock 112 A.
- the force deflection device 300 is in the form of a spring.
- the needle drive mechanism 301 accelerates during the stitch cycle (i.e., the downward stroke of the needle 102 ), consequently pulling the thread 101 with an abruptly increased force.
- the spool 103 and cartridge interface are designed to at least partially resist spinning of the spool.
- the sudden acceleration applied to the thread 101 by the needle drive mechanism combined with the inertial force applied to the thread 101 by the spool 103 and the resistance to spinning of spool 103 be design, abruptly increases the tension on the thread 101 , which can lead to uneven thread tension during the stitching process.
- the force deflection device 300 is designed to deflect or deform when the needle drive mechanism 301 accelerates during the stitch cycle. In this way, some of the initial force applied by the needle drive mechanism 301 to the thread 101 during the stitch cycle is transferred to the force deflection device 300 , rather than having all of that initial force transferred directly to the spool 103 .
- the force deflection device 300 is able to reduce the sudden increase in tension typically experienced by the thread 101 .
- the deformation of the force deflection device 300 acts to absorb the peak energy applied by the needle drive mechanism 301 to the thread 101 .
- the spring 300 is placed in the thread path between the spool 103 and a thread guide 302 , which serves to guide the thread from the spool 103 into the upper thread lock 114 A and the needle drive mechanism 301 .
- the needle drive mechanism 301 accelerates downward, the thread 101 is pulled off the spool 103 .
- the spring 300 further deflects in a downward motion.
- the spring 300 is designed as a cantilever beam with a stiffness that is optimized to operate within the range of needle drive acceleration and amount of thread on spool (the diameter of thread on the spool affects spool inertia, from engineering theory).
- the force deflection device 300 could take the form of a coiled spring which deforms by compressing when the needle drive mechanism 301 accelerates downward.
- the exact form of the force deflection device 300 is not important, so long as it is designed to deform to absorb some of the initial force applied by the needle drive mechanism 301 to the thread 101 .
- the force deflection device 300 should be optimized to operate within the range of needle drive acceleration, amount of thread on the spool, and friction in the spool/cartridge interface. It has been determined that the initial force applied by the needled drive mechanism 301 to the thread 101 is in the range of 10 to 100 g-force, with around 50 g-force being a commonly applied initial force. Thus, the force deflection device 300 best serves its purpose when designed to deform under such an applied force range.
- the material used to make the force deflection device 300 can be a metal, a rubber, a plastic, or any other material with an elastic property such that it will deform when 10 to 100 g-force is applied, and then return to its initial shape when the needled drive mechanism 301 no longer applies a feeding force to the thread 101 .
- the material used to make the force deflection device 300 might be chosen such that the deflection device 300 only deforms when at least 50 g-force is applied thereto.
- the force deflection device 300 can be applied to any device or process which serves to feed, pull, draw, or otherwise remove a material from a spool.
- the force deflection device 300 could be applied to a situation where rope or chain material is to be fed from a spool. All that would be required is to adjust the force range in which the force deflection device 300 deforms to absorb the initial feed force.
- a workpiece embroidered by the single-thread sewing device described above will further require a separate means for permanent retention of the stitches in the workpiece. This may be accomplished by separate application of an adhesive to secure the thread loops to each other or to the underside of the workpiece.
- a detection device and method therefor comprising a sensor positioned to detect the physical movement of a needle drive mechanism 301 in a sewing apparatus.
- the needle drive mechanism 301 includes moving mechanisms of the thread feed mechanism 100 as described above (see FIGS. 5A-5C ), such as the thread feed body 110 and the presser foot 118 . While the embodiments described herein show exemplary removable cartridges 100 configured to allow each needle drive mechanism 301 to move while the corresponding fixed cartridge 100 is stationary, it will be understood that the detection mechanism 60 can be used with sewing apparatuses 1 in which where the entire cartridge 100 moves with the needle drive mechanism 301 , as shown in U.S. Pat. Nos. 6,729,253 and 6,729,254 (the entirety of each of which is incorporated by reference herein).
- lever 63 is added underneath the embroidery deck 61 .
- the lever 63 is able to pivot.
- the needle drive mechanism 301 moves downward during the downward stroke and contacts the lever 63 , the resulting downward movement of the lever 63 actuates a sensor 65 such as a mechanical switch or photo interrupter. From this actuation, the position of the needle 102 is known.
- the needle position can be detected with high precision.
- a drive mechanism 24 can be, for example, a steady drive motor such as a DC drive motor 24 .
- a variable or intermittent drive mechanism 24 such as a stepper motor 24 for driving the needle drive mechanism 301
- the stepper motor 24 can lose position if subjected to too high of a load. If this occurs, the position of the needle 102 may no longer be known if operating in open loop control. This can result in significant degradation of stitch quality.
- a lever is mounted underneath the embroidery deck 61 in the configuration of a cantilever beam as shown in the embodiment of FIGS. 6 A-D, thereby creating a closed loop system.
- the lever is attached to the deck 61 using a hinge 64 such as a piece of plastic, metal, or any other deformable material that meets the functional requirements of the detection mechanism 60 .
- a hinge 64 such as a piece of plastic, metal, or any other deformable material that meets the functional requirements of the detection mechanism 60 .
- embodiments of the device 60 include embodiments where elements such as the lever 63 , hinge 64 and needle plate 62 are each separately incorporated into the deck. Also, one or more of these elements can be unitarily formed as parts of the deck 61 , as for example, by a one-piece injection molded deck 61 including the lever 63 , hinge 64 and needle plate 62 .
- the up position is shown in FIG. 6A .
- the presser foot 118 contacts the workpiece 18 , which in turn contacts the needle plate 62 , resulting in the downward pivot of the lever 63 .
- the needle plate 62 positioned on the lever 63 , such that the downward motion of the presser foot 118 on a workpiece 18 causes the workpiece 18 to contact the needle plate 62 so that the lever 63 contacts the sensor 65 , shown as a mechanical switch.
- the sensor 65 In the down-most position of the lever 63 (shown in FIG. 6B ), the sensor 65 is actuated and the lever 63 contacts the stop 66 , which stops or substantially stops the downward motion of the lever 66 .
- the lever 66 With the stop 66 , the lever 66 is unable to over-travel, thus preventing wear and possible damage to the switch 65 .
- the needle plate 62 is attached to the lever 63
- the device could be configured in any number of ways to affect a lever 63 and/or needle plate 62 to actuate a sensor 65 .
- a flag could be attached to the lever 63 such that the lever 66 actuates a photo interrupter (not shown).
- the sensor 65 can comprise an emitter such as a light source and a detector such as photodiode.
- a flag can be positioned on the lever 63 such that it interrupts a signal between the emitter and the detector, for example, a light signal to the photodiode.
- the distances from the pivot or hinge 64 to the switch 65 , needle plate 62 , and stop 66 can be optimized for range of motion and force.
- the needle position can be detected with high precision.
- At least one of the pivot point 64 for the lever 63 , the sensor 65 , and the stop 66 can be positioned to optimize at least one of a range of motion of deflection as well as a force.
- the device 60 can further be configured such that at least one of the pivot point 64 , the sensor 65 , and the stop 66 is positioned to optimize at least one of the desired qualities of the sewing apparatus.
- desired qualities may include reduced wear on the device 60 from repeated operation, as well as stitch delivery from the needle mechanism to the workpiece 18 .
- the force on the needle plate 62 required to actuate the switch 65 can be adjusted by shifting the position of the needle plate 62 relative to the pivot 64 .
- the factors for the optimizing the configuration are expressed as follows in conjunction with FIG. 6E :
- F NP ((D SW /D NP )*F SW )+force contribution from hinge stiffness (assuming contribution from mass of lever and needle plate are negligible)
- the sensor 65 included in the detecting mechanism 60 is configured to detect the physical movement of the needle mechanism.
- the sensor 65 sends a signal to the controller 70 , such that the sensor 65 and the drive mechanism 24 form a closed feedback loop operable to allow the CPU 71 A to track the position of the needle drive mechanism 301 of the thread feed mechanism 100 with respect to a workpiece 18 for the needlework during operation.
- the sewing apparatus 1 comprises a plurality of the thread feed mechanisms 100 .
- the detection mechanism 60 and the drive mechanism 33 for each thread feed mechanism 100 form a closed feedback loop, which is operable to track the position of each of the thread feed mechanisms 100 (including the needle drive mechanism 301 ) with respect to a workpiece 18 for the needlework during operation.
- the sewing apparatus 1 comprises a plurality of the sensors 65 . Each of the plurality of sensors 65 are configured to detect the movement of the each of the thread feed mechanisms 100 , as well as determine the position of each needle 102 with respect to the workpiece 18 during operation of the sewing apparatus.
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Abstract
A material feeding device includes material wrapped around a spool, the spool rotating around an axis. A material feeding mechanism feeds the material in a feeding direction, thereby unraveling the material from the spool. A force deflection device is arranged between the spool and the material feeding mechanism, and is connected to the material. The force deflection device is configured to as to deform physically when the material feeding mechanism applies an initial feeding force to the material.
Description
- 1. Field of the Invention
- The present invention relates to a device and method for absorbing some of the initial force/energy exerted by a thread delivery device. Such a device and method are particularly useful when applied to sewing and embroidery machines. However, this device and method are equally applicable to any similar type of feeding device (e.g., a device that feeds string, rope, chain, etc.).
- 2. Description of Related Art
- Prior art sewing and embroidery machines use a needle or some other feed device to pull thread from a spool so that the thread can be delivered to, and penetrated through, a material that is to be stitched. These devices transfer most of the initial force exerted on the thread by the feeding device directly to the thread spool (with some force obviously being lost due to friction).
- Some of the undesirable effects of this technique are variable thread tension and spool over-spinning.
- With such a variable thread tension, it is difficult to ensure proper tension in the thread stitches. Thus, the quality of the stitches made may be adversely affected. In addition, this variable thread tension can result in thread slippage at the point where the thread feeding device engages with the thread. If such thread slippage occurs, then the actual amount of thread that is fed is less than the intended amount. Thus could result in an inadequate amount of thread being provided for the current stitch. In this case, the additional thread needed for the stitch would be pulled from the previous stitch, which could negatively affect the stitch quality. In fact, if too much additional thread is pulled from the prior stitch, then the prior stitch could be pulled completely out of the workpiece. This presents a significant problem.
- Spool over spinning only adds to these problems. More specifically, spool over-spinning causes more thread to be pulled from the spool than is intended, which often results in the over-pulled thread causing a mechanical jam in the sewing or embroidery machine. In addition, even if the over-pulled thread does not cause a mechanical jam, the over-pulled thread presents less resistance the next time the feeding device attempts to pull the thread, since the rotational resistance of the spool does not need to be overcome in order to remove the over-pulled thread from the spool. This only serves to exacerbate the variable thread tensioning problems discussed above.
- The above problems associated with typical thread feeding devices result in a negative impact on the stitch quality of the sewing or embroidery machine, particularly at fast stitching speeds.
- The above problems particularly present themselves when using an alternative to conventional lockstitch embroidery, which employs a replaceable cartridge containing a needle and embroidery thread, supplied pre-threaded by means of a hollow needle of the type commonly used for intravenous injection. A stitching mechanism creates underside loops retained in the workpiece by friction (so called “single-needle” embroidery or stitching).
- Prior art machines of this type have the capacity to install only a single cartridge at one time, such that an embroidery pattern of several colors requires several cartridge changes performed by the user, interrupting an otherwise automated process. Embroidery patterns commonly comprise eight or more colors, resulting in a tedious operation to produce a single finished workpiece.
- In addition, since this type of machine has unsecured loops of thread hanging from the bottom of the workpiece, the above described problems of variable thread tension and spool over-spinning are magnified.
- Arranging a force deflection device (such as a spring) in a sewing machine (including an embroidery machine) between the point at which the thread feeding device engages with the thread and the point at which the thread is wound around the spool, has been determined to absorb some of the initial force exerted on the thread by the feeding device. As such, spool over-spinning can be greatly reduced, and in some cases illuminated.
- To this effect, a material feeding device is provided which includes material wrapped around a spool, the spool rotating around an axis. A material feeding mechanism feeds the material in a feeding direction, thereby unraveling the material from the spool. A force deflection device is arranged between the spool and the material feeding mechanism, and is connected to the material. The force deflection device is configured to as to deform physically when the material feeding mechanism applies an initial feeding force to the material.
- A method of feeding a material from a spool is also provided. The method involves using a material wrapped around a spool (which rotates around an axis). An initial feeding force is applied to the material so as to unravel the material from the spool. A force deflection device, which is connected to the material, is physically deformed and absorbs a portion of the initial feeding force before the initial feeding force is transferred to the thread on the spool.
- A machine containing multiple cartridges installed concurrently promises greatly enhanced utility and convenience by reducing the number of user interventions per finished workpiece. For example, a machine with capability to hold and sequentially operate four cartridges can reduce the number of user interventions required to produce an eight-color pattern from seven to just one. Such a machine includes embodiments that: reduce the quantity and mass of moving parts per needle as compared with prior art designs, such that increased power supply is not required; and incorporate a means for selectively engaging the operation of a desired cartridge through cooperative employment of existing machine mechanisms.
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FIGS. 1A-1C show a sewing apparatus. -
FIG. 1D shows a cutaway perspective view of an upper body and an embroidery frame of the sewing apparatus. -
FIGS. 2A and 2B show, respectively, a cutaway perspective view and plan view of the base portion of the sewing apparatus showing an embroidery frame driving mechanism. -
FIG. 3 shows profile views of frame engagement mechanism arranged as a schematic flow showing the operation sequence thereof. -
FIGS. 4A-4C show a thread feed cartridge selection and engagement mechanism. -
FIGS. 5A-5D show embodiments of a thread feed mechanism. -
FIGS. 6A-6E show embodiments of a detection device. -
FIG. 7 shows a controller for the sewing apparatus. -
FIGS. 8A and 8B show, respectively, how a fixed thread position is maintained relative to the needle tip during downward motion of the needle to make a stitch, and how a static position of the thread relative to the workpiece is maintained during the upward motion of the needle after a stitch has been made. -
FIG. 9 shows various parameters required by the controller in order to determine a first amount of thread needed to make a stitch. -
FIG. 10 shows a top side view of a portion of the workpiece in which one stitch has been made at location X1,Y1 and a next stitch has been made at location X2,Y2. -
FIG. 11 shows a situation where the desired loop length is smaller than the height of a slack position of the needle. -
FIG. 12 shows how, between needle cycles, the needle is positioned at a slack position during the XY movement of theworkpiece 18. -
FIGS. 13A-13E show the needle cycles through up/down movements and the workpiece moves in XY directions to form the stitches. - It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements which are conventional in this art. Those of ordinary skill in the art will recognize that other elements are desirable for implementing the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein.
- The use of the terms “a”, “an”, “at least one”, “one or more”, and similar terms indicate one of a feature or element as well as more than one of a feature. The use of the term “the” to refer to the feature does not imply only one of the feature and element.
- When an ordinal number (such as “first”, “second”, “third”, and so on) is used as an adjective before a term, that ordinal number is used (unless expressly or clearly specified otherwise) merely to indicate a particular feature, such as to distinguish that particular feature from another feature that is described by the same term or by a similar term.
- When a single device, article or other product is described herein, more than one device/article (whether or not they cooperate) may alternatively be used in place of the single device/article that is described. Accordingly, the functionality that is described as being possessed by a device may alternatively be possessed by more than one device/article (whether or not they cooperate). Similarly, where more than one device, article or other product is described herein (whether or not they cooperate), a single device/article may alternatively be used in place of the more than one device or article that is described. Accordingly, the various functionality that is described as being possessed by more than one device or article may alternatively be possessed by a single device/article.
- The functionality and/or the features of a single device that is described may be alternatively embodied by one or more other devices which are described but are not explicitly described as having such functionality/features. Thus, other embodiments need not include the described device itself, but rather can include the one or more other devices which would, in those other embodiments, have such functionality/features.
- The present invention will now be described in detail on the basis of exemplary embodiments.
-
FIGS. 1A to 1D show asewing apparatus 1, embodied as an embroidery apparatus. The sewing apparatus includes asewing apparatus body 2,safety cover 15 hingedly attached to thesewing apparatus body 2, anembroidery frame 11, and a plurality ofsewing cartridges embroidery frame 11 and thesewing cartridges 100 are detachably attached to thesewing apparatus body 2. Aworkpiece 18 to be sewn is held in theembroidery frame 11, and ahollow needle 102 capable of penetrating into theworkpiece 18 is provided in eachsewing cartridge 100. - The
sewing apparatus body 2 includes acasing 10, an embroideryframe driving mechanism 9 that moves theembroidery frame 11 having thework cloth 18 in a horizontal plane with respect to thehollow needle 102 while theembroidery frame 11 is held by acarriage 9. Thebody 2 also comprises and a selective engagement mechanism (SeeFIGS. 4A-4C ) for selecting acartridge 100 from the plurality ofcartridges - The
casing 10 is a relatively small rectangular solid. For example, in one embodiment thecasing 10 may be 14 inches (356 mm) long, 9 ½ (241 mm) inches wide and 5 ½ inches (139 mm) high. Thecasing 10 contains main parts of the embroideryframe driving mechanism 9 and the cartridge driving mechanism 109, and theselective engagement mechanism 200. - A
slot 5, allows access of theembroidery frame 11 into theapparatus 1 for sewing during operation of theapparatus 1. In one embodiment, theslot 5 extends in a lateral direction along afront wall 10 c of theapparatus 1, and is formed in afront wall 10 c between abase portion 2 b and atop portion 2 a of theapparatus 1. In another embodiment, thecasing 10 is formed as a unitary body (as shown inFIG. 1A ) and theslit 5 is runs laterally along afront wall 10 c and partially down theside walls casing 10. Theslit 5 is provided as to attach theembroidery frame 11 to anengagement mechanism 20 to engage theembroidery frame 11 to the embroideryframe driving mechanism 9 and to move theembroidery frame 11 in a horizontal plane. On the right side of theupper surface 10 a is apower switch 3, and a start/stop switch 4 that starts and stops the sewing. Upper surfaces of thepower switch 3 and the start/stop switch 4 are positioned at the same or a slightly lower level than the upper surface of theupper wall 10 a. -
FIG. 1D shows a cutaway perspective view of theupper body 2 a and anembroidery frame 11, in an embodiment where theupper body 2 a forms a cover portion of thesewing machine 1. Theapparatus 1 comprises aremovable embroidery frame 11, abody 2 of the apparatus, and a frame and drive engagement mechanism 50 (SeeFIG. 3 ) for engaging the frame to aframe driving mechanism 9. Theapparatus 1 further comprises at least onemating alignment feature frame 11 with the apparatus, wherein the mating alignment feature allows engagement of the embroidery frame to the apparatus where the frame and driveengagement mechanism 50 are at least partially obscured. - In the embodiment, the mating alignment feature further comprises a
frame alignment feature 12 on theembroidery frame 11 and a bodymating alignment feature 6 corresponding to the frame alignment feature. With respect to thefront side 10 a of theupper body 2 a of the cover, a raisedalignment feature 12 is added to the leading edge of theembroidery hoop 11 where the leading edge is to be inserted into theengagement mechanism 20 within theembroidery apparatus 1. To enable correct insertion of theembroidery hoop 11 into thesewing apparatus 1, acutout 6 of a shape corresponding to the raisedfeature 12 on theembroidery frame 11 allows clearance through thetop portion 10 a of theembroidery machine 1. Thecutout 6 is positioned on thefront face 10 c of thetop portion 2 a to facilitate direct access to the frame and drive engagement mechanism 50 (SeeFIG. 3 ) within the machine. As shown in the embodiment, thecutout 6 has a negative space profile that corresponds to the shape of the raisedalignment feature 12. - It will be noted that although the present embodiment has the raised
alignment feature 12 on theframe 11 and thecutout alignment feature 6 on thebody 2, the frame could be made in an embodiment (not shown) such that thecutout feature 6 is on the frame and the raisedfeature 12 is on thebody 2 a (e.g., via agroove cutout feature 6 and raisedfeature 12 comprising guide element 7 formed as a notchedrail 12 on the underside of theupper body 2 a). - The apparatus further comprises a guide element 7, shown as a guide channel 7 configured such that the
embroidery frame 11 can be moved through the body to a point of engagement with the frame and drive engagement mechanism 50 (FIG. 3 ). A guide channel 7 is provided within thetop portion 2 b, leading from thecutout opening 6 of theupper body portion 2 a to the point of engagement with theengagement mechanism 20. In this way, reliable engagement of theembroidery frame 11 with embroideryframe driving mechanism 9 is assured, even though the frame engagement and drivemechanism 50 is hidden or at least partially obscured from the view of the operator (as is the case in the present embodiment where thebody 2 a obscures the view if not made of a transparent material). As shown inFIG. 1D , the guide channel comprises slopedrail elements cutout 6. - The raised
alignment feature 12 of theembroidery hoop 11 is larger than theslot 5, through which theframe 11 otherwise passes into themachine 1 during bothframe 11 insertion andmachine 1 operation. Accordingly, this raisedfeature 12 effectively prevents insertion of theembroidery frame 11 into themachine 1 to the degree that theframe 11 may be lost accidentally from the reach of the operator's finger grip. - The mating alignment features 6, 12 of the
upper body 2 b and theframe 11 of the machine cover are chosen to be of a distinct and easily recognizable shape, thereby facilitating intuitive recognition of the insertion direction. Thus while the raisedfeature 12 and thecutout 6 both take a similar polygonal form as shown inFIG. 1D , other such intuitively recognizable shapes could be chosen (such as semi-circular, square, or even a whimsical design element such as a clover, a distinctive symbol or mark, or an animated character's profile). Once aligned, alatching mechanism 14 for theengagement frame 11 is further operated by intuitive, tactile push/pull engagement and disengagement of theframe 11, which is described in more detail below (SeeFIG. 3 ). - A
latching mechanism 14 for theengagement frame 11 is further operated by intuitive, tactile push/pi 11 engagement and disengagement of theengagement frame 11 once aligned, using the intuitive mating alignment features 6, 12 as shown inFIG. 1D . The latching mechanism 44 engages with aframe driving mechanism 9 for moving theworkpiece 18 in the horizontal plane within theembroidery machine 1. As shown inFIGS. 2A and 2B , thecarriage 9 has anengagement portion 16 that can engage/disengage aninstallation portion 14 of theembroidery frame 11 thereto/therefrom. -
FIGS. 2A and 2B are respectively a cutaway perspective view and plan view of thebase portion 2 b of thesewing apparatus 1 showing the embroideryframe driving mechanism 9. An exemplary embroidery frame driving mechanism which can be employed in the embodiments of the invention described herein is also shown in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein. The embroideryframe driving mechanism 9 includes thecarriage 8 to which theembroidery frame 11 is detachably attached, an X-axisdirection driving mechanism 20 that drives thecarriage 8 in an X direction (the left-right direction as shown) within a horizontal plane, and a Y-axisdirection driving mechanism 25 that drives thecarriage 8 in a Y direction (the front and rear direction as shown) perpendicular, within the horizontal plane, to the X direction. - The X-axis
direction driving mechanism 20 includes a movingframe 24, anX-axis slider 22 attached to aX-axis drive belt 21, and anX-axis guide shaft 23. Thedriving mechanism 20 is operatively connected to adrive motor 29. The movingframe 21 is rectangular moves with a Y-axis slider 28. Theguide shaft 23 is supported at its ends by side walls of the movingframe 21. - The Y-axis
direction driving mechanism 25 includes the Y-axis slider 28 attached to a Y-axisbelt drive belt 27 and a Y-axis guide shaft 26. The Y-axisdirection driving mechanism 25 is also operatively connected to adrive motor 29. - The Y-
axis slider 28 is disposed under and attached to the X-axisdirection driving mechanism 20, such that the movingframe 21 moves with the Y-axis slider 28. - An embodiment of the frame and drive
engagement mechanism 50 is shown atFIG. 3 . The engagement mechanism includes a fixedguide 15, comprising achannel 17 formed by at least oneguide member 15 and alatch mechanism 14 configured to engage aframe catch member 16 on the frame to theframe driving mechanism 9. Thechannel 17 is configured to position thelatch mechanism 14 and thecatch member 16 such that thelatch mechanism 14 engages and disengages theframe catch member 16 at a fixedlocation 19. A controller 70 (discussed below) controls theframe driving mechanism 9, and is configured to position the latch mechanism at the fixedlocation 16. Thechannel 17 has adrive engagement side 29 and aframe engagement side 28. - As shown in
FIG. 7 , thecontroller 70 of thesewing apparatus 1 has a computer 71, which includes aCPU 71 a, aROM 71 b, aRAM 71 c, an input/output interface 71 d, and an input/output terminal 71 e. TheCPU 71 a, theROM 71 b, theRAM 71 c, the input/output interface 71 d, and the input/output terminal 71 e are operatively connected to each other, as for example via a bus. The input/output interface 71 d is connected with adrive circuit 20 a for thepulse motor 20 x of the X-axisdirection driving mechanism 20, adrive circuit 25 a for thepulse motor 25 y of the Y-axisdirection driving mechanism 25, adrive circuit 24 a for thedrive motor 24 of the thread feed andengagement driving mechanism 30, the power switch, and the start/stop switch 4. Exemplary controller and computer systems that can be used in conjunction with the present invention are described in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein. Also shown is asensor 65 forming part of a detection mechanism 60 (SeeFIG. 6A-FIG . 6E) operatively connected to theCPU 71 a, theROM 71 b, theRAM 71 c, the input/output interface 71 d, and the input/output terminal 71 e. - The
controller 70 includes adrive 72 capable of reading and writing instructions frommemory 73, including internal memory or memory from a storedmemory device 73. Thedrive 72 can be any device configured to read memory such as flash drives, CDs or DVDs, cartridges, memory cards, and other like devices, and includes hardware for interfacing therewith. The stored memory device can be an external storage medium, such as a memory cartridge, memory card, flash drive, CD or DVD, or other like device. The stored memory device can even comprise remote storage 73 b transmitted over WAN or LAN networks, including those such as in cloud computing and storage systems. Thememory 73 stores various sewing data and programs, so that the sewing data and the programs are readable by the computer 71. Similarly, the control programs, the control signals, and the data may be distributed worldwide via the Internet. - In the
sewing apparatus 1, an embroidery pattern can be formed on theworkpiece 18 by controlling the embroidery frame driving mechanism 29 (the X-axisdirection driving mechanism 20 and the Y-axis direction driving mechanism 25) and the threadfeed driving mechanism 100 by thecontroller 70 based on the sewing data. A control program for sewing is stored in theROM 71 b. - The
memory storage 73 stores various kinds of embroidery patterns, pattern data of various kinds for prestored embroidery patterns, and a pattern selection control program for selecting a desired embroidery pattern from the various kinds of embroidery patterns. Thememory storage 73 also can include a pattern edit control program for editing (e.g., enlargement, reduction, unification, reversal) a selected embroidery pattern, and a display control program for displaying an embroidery pattern for selecting and setting on a display (not shown). For example aflash card 73, connectable to the flash card connector, can store pattern data of a selected/edited embroidery pattern. -
FIG. 3 shows profile views arranged as a schematic flow showing the operation sequence designed to position thelatching mechanism 14 at a specific position of engagement and disengagement when the installation or removal of theembroidery hoop 11 is indicated. Thecontroller 70 includes machine software and hardware (SeeFIG. 7 ) that controls this movement. By interaction with theupper body 2 a cover of the machine at a specific location, thelatching mechanism 14 is designed to allow manual disengagement of theembroidery hoop 11. In this way, accidental disengagement of the hoop from the machine during other modes of operation can be prevented. - As shown in
FIG. 3 (at 200), thelatch mechanism 14 is moved into an engagement position against a fixedguide member 15. In the current embodiment, the engagement position is achannel 17 formed by two fixedguide members controller 70 moves the drive-side 29frame engagement mechanism 14 to the fixedguide members drive engagement side 29 to aframe engagement position 19. - The
catch member 16 on the frame engages thelatch mechanism 14 at theengagement position 19. The oneguide member 15 b is shorter than theother guide member 15 a. This allows thelatch mechanism 14 to move into a stationary engagement/disengagement position by abutting theshorter guide member 15 b, and sliding underneath the longer guide member such that thelatch protrusion 14 a has a spring tension against theupper guide member 15 a. - The
catch member 16 of the drive engagement mechanism includes anopening 16 a, and is positioned into anengagement position 19 from theframe engagement side 28 of the fixed guide member. As shown at 210, the hoop orframe catch member 16 is separately guided into thechannel 17 from theframe entry end 28, moving the catch member opening 16 a along thechannel 17 formed by the fixedguide members latch mechanism 14 is displaced under thecatch member 16 until the catch member opening 16 a reaches theengagement position 19. At 220, theprotrusion 14 a of thestationary latch mechanism 14 meets theframe catch member 16 and engages a slot or opening 16 a of the catch. Thelatch protrusion 14 a includes at least onebeveled edge 14 b, which is adapted to allow the fixedguide member 15 a andcatch member 16 to displace thelatch mechanism 14 when thelatch mechanism 14 is moved against the fixedguide member 15 a or thecatch member 16. The fixedguide member 15 a and thecatch member 16, respectively, have reciprocally slopedbevels latch mechanism 14 when moved against the fixedguide member 15 or thecatch member 16. - At 220 the
frame catch member 16 is placed at a position where a user can no longer move theframe catch member 16 further into the sewing apparatus, as for example, against a stop (not shown). At this point theprotrusion 14 a of thelatch mechanism 14 partially engages thecatch slot 16 a, up to the point where thelatch protrusion 15 a abuts the upperfixed guide member 15 a. This creates highly tactile engagement that is felt by a user as thelatch mechanism 14 snaps into position. Accordingly, a user intuitively knows by this sensation that theframe 11 is engaged without needing to rely on a visual cue. At 230 theframe catch member 16 andlatch mechanism 14, thus engaged, are moved into the machine workspace by the machine software (not shown). It will be noted that as thelatch mechanism 14 moves the frame into the sewing apparatus, the latch fully engages the catch member as it passes out of theguide member 15. - Disengagement and removal of the
embroidery frame 11 is accomplished by reversing steps 200-230. As with the engagement, thelatch protrusion 14 includes the at least onebeveled edge 14 b, which allows the fixedguide member 15 a to again displace thelatch mechanism 14 when thelatch mechanism 14 is moved against the fixedguide member 15 a (as in going fromstep 230 to step 220). During disengagement, the fixed guide member's slopedbevel 15 c facilitates the displacement of thelatch mechanism 14 when moved against the fixedguide member 15. - The
sewing apparatus 1 can be configured to have a plurality of thread feed mechanisms, shown asremovable cartridges FIGS. 1A-1C , in one embodiment thesewing apparatus 1 comprises 4 cartridges. However, the apparatus as described herein could be adapted to include any number of cartridges 100 n. Each cartridge could, for example, have a different colored thread, thereby allowing a preprogrammed embroidery pattern utilizing many different colors to be completed with fewer runs of theapparatus 1. For example a preprogrammed pattern with 4 colors could be completed in one run of the apparatus configured to simultaneously include 4cartridges cartridges -
FIGS. 4A-4C show a thread feed cartridge selection andengagement mechanism 30 which is operatively connected to the embroideryframe driving mechanism 9. Thesewing apparatus 1 comprising a fixedcartridge 100 and moving needle 102 (SeeFIGS. 5A-B ) can reduce the power consumed in stitching theworkpiece 18. Instead of moving the entire cartridge mass (including a large thread spool 103), the current embodiment moves only theneedle 102 and related mechanisms of low-inertia design. This is accomplished by means of a gear train (described herein) that selectively transmits power from adrive motor 24 to a rack-mountedneedle 102 within thecartridge 100. The reduced inertia of moving parts requires less energy to achieve the required accelerations in opposite directions on each stitching cycle. -
FIG. 4A shows one embodiment of a system and method for a thread feed selection andengagement mechanism 30. As shown, thesewing apparatus 1 comprises adrive mechanism 24, a thread feed mechanism comprising aremovable cartridge 100, and aneedle engagement mechanism 104 for engaging the thread feed mechanism. The drive mechanism comprises adrive motor 24 configured to transmit power from thedrive motor 24 to the needle engagement mechanism, such that thedrive motor 24 drives a needle within the cartridge without moving the entire cartridge. - The thread feed selection and
engagement mechanism 30 in the embodiment includes aspur gear transmission 30, comprising a movableoutput drive gear 33 capable of selective engagement with one of several installedcartridges single drive motor 24 can be employed to select and drive each cartridge in theapparatus 1 when a plurality ofcartridges - In one embodiment, the
selective engagement mechanism 30 is actuated by a complimentary function of the X-Y embroideryframe driving mechanism 9 and thecontroller 70 therefor, as described herein. Thedrive mechanism 9 andcontroller 70 are of a design otherwise commonly employed in embroidery machines as known to those of ordinary skill in the art (such as that shown in U.S. Pat. Nos. 6,729,253 and 6,729,254, the entirety of each of which is incorporated by reference herein). Thus one exemplary advantage of theselective engagement mechanism 30 is that it can be configured to work in conjunction with an existing mechanism to add functionality thereto. - The controller 71, and
machine operating software selective engagement mechanism 30 so as to arrange theselective engagement mechanism 30 to position aselector lever 31 at a predetermined location facilitating engagement from the Y-direction. This is followed by a sequence of coordinated movements of theselective engagement mechanism 30 in the X-Y directions, a first sweep of theselective engagement mechanism 30 intended to intercept and move a keyeddrive gear mechanism 33 from any position on thedrive shaft 32 to a predetermined position at the end of the sweep, and a second sweep of theselective engagement mechanism 30 in the opposite direction terminating so as to position the keyeddrive gear mechanism 33 in the location of engagement with thedrive mechanism 104 of the desiredcartridge 100. - In one exemplary embodiment, the
drive shaft 32 is operatively connected to thedrive motor 24 and at least onedrive gear 33 positioned on the shaft. The drive motor can comprise a variable speed motor (e.g., a stepper motor). Thedrive gear 33 is configured such that it can slide from position to position on theshaft 32. - Within a physically limited length interval, a
drive shaft 32 comprises a physical configuration including, for example, a shaped cross section such that akeyed drive gear 33 of suitably matched cross section mounted thereon is constrained from rotating about and relative to the axis theshaft 32, and remains free to slide parallel to the axis. Such configurations can be of a non round shape, but could also include a round cross-section with elements adapted to allow for driving the gear, such as a tab along theshaft 32 and a corresponding slot in adrive gear 33. Many specific configurations of shafts and gears accomplishing this purpose are well known in the art, such as the cross-sectional shapes including shapes a D shape, a round shape, a non-round shape, a clover shape, a notched shape, a triangular shape, a square shape, a polygonal shape, and a rectilinear shape. - In one embodiment, a D-shaft and keyed drive gear is utilized. The
drive shaft 32 is a D-shaft, and thekeyed drive gear 33 is positioned thereon to facilitate secure placement and rotation of thedrive gear 33 when theshaft 32 is rotated by thedrive motor 24. - The range of X-direction movement of the
keyed drive gear 33 on thekeyed drive shaft 32 is limited to maintain positional control at all times and without risk of jamming, by ensuring that the selector can be safely positioned to begin each sweep outside the allowed range of drive gear movement on the shaft. Thecontroller 70 is further configured to position the frame driving mechanism 9 (including theselector 31 in anarea 45 outside of awork area 47 for the workpiece) to position theselector 31 to engage thedrive gear 104. - As shown in
FIG. 4C thecontroller 70 is configured to position the selector outside the work area by moving the frame mechanism in the Y-direction. 25. Thecontroller 70 is further configured move theselector 31 in a first sweep to intercept and move thekeyed drive gear 33 from any position on thedrive shaft 32 to a predetermined position at the end of the sweep, and a second sweep in the opposite direction terminating so as to position thekeyed drive gear 33 in the location of engagement (postitions 1-4) with thedrive mechanism 104 of thethread feed mechanism 100. Thecontroller 70 is further configured to limit the range of X-direction movement of thedrive gear 33 on thedrive shaft 32, such that theselector 31 is positioned to begin each sweep outside the limited range ofdrive gear 33 movement on theshaft 32. Additionally thedrive shaft 32 can also be physically configured to mechanically limit the range of X-direction movement of thedrive gear 33 on thedrive shaft 32 such that theselector 31 is positioned to begin each sweep outside the limited range ofdrive gear 33 movement on theshaft 32. For example, thedrive shaft 32 can include a shaped cross-section such as a D-shaft. Thedrive gear 33 is keyed to the D-shaft and slideably positioned on the shaped cross-section to move along its axis, as described herein. The longitudinal cut of the cross-section on theshaft 32 can end in a position that limits the X-direction movement of thedrive gear 33 on thedrive shaft 32, as, for example where the keyed D cross-section in thegear 33 abuts theshaft 32 at a point where the D-cut cross-section into theshaft 32 ends. - The needle drive mechanism includes an
idler gear 104 in a housing positioned to engage the drive gear and thethread feed mechanism 100. Aselector 31 is attached to theframe driving mechanism 9. Theselector 31 is configured to engage thedrive gear 104 with the thread feed mechanism, and move the drive gear to any position (for example, 4 positions corresponding to the 4cartridges 100 a-100 d). As shown inFIGS. 4A-4C ,needle engagement mechanisms 104 a-104 d are configured to engage thedrive gear 33 to each of the cartridges. Thecontroller 70 is configured to move theframe driving mechanism 9 to position the drive gear such that the drive gear engages thethread feed mechanism 100. Areduction gear 40 and driveshaft 40 are provided between thedrive shaft 32 and thedrive motor 24 to control the torque delivered from thedrive motor 24. Alocking mechanism 43 locks thedrive gear 33 when thedrive gear 33 engages aremovable cartridge 100. In one embodiment, thelocking mechanism 100 can include a detent on thedrive shaft 32 to lock thedrive gear 33 into a position wherein it can drive the needle engagement mechanism without slipping or sliding out of position. The detent is configured to lock the gear into position yet also allow the selector to move the gear between positionsthread feed mechanisms 100 a-100 d. - The needle engagement mechanism can be configured to engage at least one thread feed mechanism, the thread feed mechanism comprising a removable cartridge. This can be accomplished by selecting at least one drive gear, and moving the drive gear to engage the at least one thread feed mechanism. The
controller 70 moves the frame driving mechanism to position the drive gear such that the drive gear engages thethread feed mechanism 100. Theengagement mechanism 30 slides the at least onedrive gear 33 to a needle engagement position, the drive gear being mounted on a shaft operatively connected to adrive motor 24 for driving thethread feed mechanism 100. Theframe 11 is positioned outside of a work area for aworkpiece 18 when selecting and moving thedrive gear 33. For example, when selecting and moving the drive gear, the X-Yframe driving mechanism 9 moves theframe 11 in the Y-direction. Theselector 31 is then positioned to engage a sequence of coordinated movements in the X-Y directions, so as to position thedrive gear 33 such that thedrive gear 33 engages adrive mechanism 104 of the thread feed mechanism. - The positioning of the
selector 11 includes moving theselector 11 in an X direction to afirst drive gear 33 position (any of p-1 to p-4), moving theselector 11 in a Y direction to select thedrive gear 33, and then sliding thedrive gear 33 in an X direction from the first drive gear position on the drive shaft to a second position on the drive shaft (any of p-1 to p-4 other than the first position), the second position being the location of engagement with thedrive mechanism 104 of thethread feed mechanism 100. As theFIG. 4C shows, the range of X-direction movement of thedrive gear 33 on thedrive shaft 32 is such that theselector 11 is positioned to begin each sweep outside the limited range ofdrive gear 33 movement on theshaft 32. Thedrive gear 33 is locked when thedrive gear 33 engages thethread feed mechanism 100. Power is then transmitted from adrive mechanism 24, for example a stepper motor, to theneedle engagement mechanism 106 such that it drives aneedle 102 within thecartridge 100. - In one embodiment, as described herein, the mechanism can drive the
needle 102 without moving theentire cartridge 100. Thesewing apparatus 1 comprises a device configured to actively feed embroidery thread out of acartridge 100 through ahollow needle 102. One advantage is that a thread break at or near the needle tip is automatically overcome through normal operation of thesewing apparatus 1. Other exemplary advantages include: (a) enabling automatic recovery of the stitching function in the case of thread breakage during embroidery; (b) eliminating any requirement for user adjustment or trimming of thread from the cartridge, prior to use or storage; and (c) enabling a complimentary function for thread cutting on the underside of the workpiece using a cutter assay (SeeFIG. 4B , 39) thereby reducing or eliminating the need for manual thread trimming at the start, finish or at “jump stitches” in the embroidered pattern. - In another aspect, disclosed is a mechanism to enforce thread advancement on each downward plunge of the needle, and further inhibit reverse thread motion on the return stroke, and methods therefor.
-
FIGS. 5A-B show embodiments of a thread feed mechanism including acartridge 100.FIG. 5B shows the embodiment of thecartridge 100 comprising a double-acting lever mechanism configured to alternately engage both moving and non-moving thread locks. - A
replaceable cartridge 100 contains athread spool 103 and a pre-threadedhollow needle 102, which are configured to be mounted within thesewing apparatus 1. Thereplaceable cartridge 100 also includes mechanisms for independent needle and thread motion control. - A
rack slider 106 is mounted in thecartridge body 100 a, therack slider 106 being constrained to allow only translation in the vertical axis. Therack slider 106 is operatively connected to theneedle drive gear 104. Thisdrive gear 104 delivers intermittent rotary motion to therack slider 106, which receives and follows that motion. As described above with respect toFIGS. 4A-4D , theneedle drive gear 104 is ultimately driven by the drive motor 24 (embodied hereby as astepper motor 24 which delivers intermittent rotary energy). In one embodiment, thedrive gear 104 can be a keyed or ridged gear adapted to engage ridges on therack slider 106. - The
rack slider 106 is configured to engage athread control lever 108, such that thethread control lever 108 is at first rotated against astop rack slider 106 motion, then further constrained to translation following therack slider 106 over a remaining stroke length. - A fulcrum 107 of the
thread control lever 108 is fixed to athread feed body 110, such that thethread control lever 108 in a first stage movement first rotates about a pivot to engage at least one thread lock 114 (discussed below), and then causes translation of thethread feed body 110 in a second stage movement. Intermittent rotary motion of thedrive gear 104 is received and followed by therack slider 106 mounted in thecartridge body 100 a, therack slider 106 being constrained to allow only translation in the vertical axis. - The
thread feed body 110 includes a constraining channel 111 for thread passage, and a lateral slot 112 through which thethread control lever 108 can engage thread lock 114B, thereby preventing motion of thethread 101 through the channel 111 during downward motion only. It will be understood the thread control lever may also engage the thread lock by a hinged connection 114B or such connection as to allow the thread control lever to engage the thread lock 114B - The
thread feed body 110 receives both theneedle 102 and an extension guide element (embodied as extension guide spring 115) fixed to thethread feed body 110 at opposite ends. - The
thread 101 is passed through theextension guide spring 115, which is fixed on the upper end of a receivingfeature 116 on thecartridge body 100. The extension guide spring acts to constrain thethread 101 at all times against significant bending, kinking, or looping within the passages formed through thecartridge body 100 a,extension guide spring 115, and the constraining channel 111B of thethread feed body 110. - The cartridge body further contains a lateral slot 112A through which the
thread control lever 108 may engagethread lock 114A, thereby preventing motion the thread in a fixed channel 111A (here shown in the fixedcartridge 100 a) during upward motion only. It will be understood the thread control lever may also engage thethread lock 114A by a hinged connection, or by such connection as to allow the thread control lever to engage thethread lock 114A. - A
cylindrical presser foot 118 surrounds and is coaxial with theneedle 102. Thepresser foot 118 is mounted on or otherwise operatively connected to therack slider 106, such that thepresser foot 118 is configured to move with therack slider 106. Thepresser foot 118 is further controlled by areturn spring 122, which is positioned to maintain a position of full extension as against thepresser foot 118 unless bearing against theworkpiece 18. As shown inFIG. 5B , thereturn spring 122 is shown as positioned between thepresser foot 118 and therack slider 106. - A
second return spring 120 is positioned to maintain therack slider 106 at the upper limit of travel, until overcome by force exerted on therack slider 106 by thedrive gear 104. As shown inFIG. 5B , thecompression return spring 122 is shown as positioned between the presser foot fixedcartridge 100 a and therack slider 106. - The return springs are shown as a compression return springs, but each could be any spring chosen as appropriate, including extension springs, torsion springs, or other such springs as known to those of ordinary skill in the art.
- A
thread lock arm 124 of thecartridge body 100 a is positioned to engage thethread control lever 108 and thread lock 114B in thefeed body 110, such that thethread 101 cannot be freely withdrawn from thecartridge 100 when the needle is positioned at the upper limit of travel. - The result of the above-described functions is that
thread 101 is positively advanced with the needle on each downward stroke of theneedle 102, and thread thus advanced is further constrained against return with theneedle 102 on each upward (return) stroke. In this way,thread 101 is actively advanced from theopen tip 102A of theneedle 102 by an amount nearly equal to the downward stroke length of each cycle. It will be noted that while the described embodiment shows two thread locks 112A, 112B, thecartridge 100 could be configured to allow a single thread lock 112 to both constrain the movement of the thread to follow the needle on the downstroke and constrain the thread to stay stationary as the needle moves on an upstroke (not shown). - It follows that a mechanism arranged to adjustably control the stroke length, also positively controls the advance of thread from the
cartridge 100 through theneedle tip 102A. Such control, in coordination with separate control of the lateral movement of an embroidery workpiece (not shown), enables the following exemplary functions and features: -
- Programmed, coordinated control of the machine mechanisms to optionally produce satin stitches or chenille loop stitches on the front design side of the workpiece.
- Active replenishment of
thread 101 from theneedle tip 102A in the event of thread breakage within theneedle 102 during operation of the machine, further enabling self-recovery of stitching in the event of thread breakage during embroidery. - Advancement of
thread 101 from theneedle tip 102A below the underside of the workpiece (not shown), further enables automated cutting of thethread 101 by a mechanism (FIG. 4D , 39) provided for such purpose, resulting in the following advantages:- attached, loose thread ends need not remain on the front design side at the start or finish of stitching of a pattern; and
- a continuous “jump stitch” need not remain on the front design side between segments of a pattern;
- where each of these conditions otherwise requires manual trimming by the machine operator following machine embroidery by prior art means.
- One embodiment of controlling the above described thread feeding mechanism will now be explained.
- As shown in
FIG. 8A , the thread feeding mechanism described above (including therack slider 106,thread feed body 110, and upper andlower thread locks 114A, 114B) maintains a fixed thread position relative to the needle tip during downward motion of the needle to make a stitch (i.e. pullingthread 101 from the spool 103), since the lower thread lock 114B engages thethread 101 when a stitch is made. As shown inFIG. 8B , the thread feeding mechanism maintains a static position of thethread 101 during the upward motion of theneedle 102 after a stitch has been made (i.e. theneedle 102 glides over thethread 101 without pulling, leaving thethread 101 fixed in position relative to the anchoring position of the previous stitch), since theupper thread lock 114A is engaged with thethread 101 at this point. With this system, tensioning of the stitches is accomplished by control of the feeding of the appropriate amount ofthread 101 through controlling the up and down motion of theneedle 102 and the engagement and disengagement of the thread locks 114 (i.e.,upper thread lock 114A being disengaged and lower thread lock 114B being engaged whenneedle 102 moves down; andupper thread lock 114A being engaged and lower thread lock 114B being disengaged whenneedle 102 moves up). This control is accomplished by variable determination of the top of the needle stroke and the bottom of the needle stroke, on a stitch by stitch basis. - To this affect, referring now to
FIG. 9 , thecontroller 70 is configured to calculate a first amount of thread AT1 needed for a particular stitch by using the following formula: -
A T1 =L S +L L −C 1 ; - where LS is the desired stitch length (i.e., the distance from one stitch anchoring XY position to the next stitch anchoring XY position in the current needle cycle); LL is the desired length of the loop formed on the underside of the
workpiece 18 as measured from the top surface of the workpiece 18 (i.e., the amount ofthread 101 needed for appropriate anchoring of the stitch in the backing material); and C1 is a small constant which is subtracted to ensure that the appropriate thread tension is provided between stitches. -
FIG. 10 shows a top side view of a portion of theworkpiece 18 in which one stitch has been made at location X1, Y1, and a next stitch has been made at location X2,Y2. Thecontroller 70 often times must also be configured to calculate the desired stitch length LS based on the known desired movement of the workpiece 18 from one stitch location X1,Y1, to the next stitch location X2,Y2. In this case, thecontroller 70 is configured to calculate the desired stitch length LS by using the following formula: -
L S=[(X 2 −X 1)2+(Y 2 −Y 1)2]1/2 ; - where X1 is the position of the first stitch in the X direction of the horizontal plane of the
workpiece 18; Y1 is the position of the first stitch in the Y direction of the horizontal plane of theworkpiece 18; X2 is the position of the next stitch in the X direction; and Y2 is the position of the next stitch in the Y direction. - In addition, as shown in
FIG. 11 , there may be a situation where the desired loop length LL is smaller than the height HS of a slack position PS (discussed below with reference toFIGS. 11 and 12 ) of theneedle 102 above the position PW of the top of theworkpiece 18 to allow for movement of theworkpiece 18 to the next stitch location. In such a situation, it may be the case that the amount ofthread 101 needed to move theworkpiece 18 from a first XY position to a second XY position will be more than the first amount of thread AT1 calculated by thecontroller 70. If this is the case, only playing out the first amount of thread AT1 from thespool 103 will result some of thethread 101 being pulled out of the previous stitch. This undesirably shortens the length of the prior thread loop, and could possibly result in the prior thread loop being pulled out of theworkpiece 18 entirely. Thus, the first amount of thread AT1 calculated by thecontroller 70 may actually be less than the actual amount of thread AT required to form the next stitch without unduly weakening the previous stitch. - To account for such a situation, the
controller 70 is configured to calculate a second amount of thread AT2 needed for a particular stitch by using the following formula: -
A T2 =[L S 2 +H S 2]1/2 . - The controller is configured to compare the first amount of thread ATI with the second amount of thread AT2, and use the greater of the two amounts as the actual amount of thread AT which is to be played out from the
spool 103. - To account for the case where the
controller 70 determines that the second amount of thread AT2 should be used, the controller is configured to increase the length LL of next loop made (when the controller uses AT2 as the actual amount of thread AT needed to make the next stitch) by the following formula: -
LLnew=(A T2 −L S)+C 2. - where LLnew is the newly determined desired length LL of next loop; and C2 is a small constant which is added to ensure that the appropriate thread tension is provided between stitches (the constant C2 may be the same value as that of the constant C1, or it may be a different value from that of the constant C1).
- Referring to
FIG. 12 , between needle cycles (i.e., one down and up cycle of the needle 102), theworkpiece 18 is moved in XY dimensions relative to theneedle 102 to provide the correct location for the next stitch. During the XY movement of theworkpiece 18, theneedle 102 must be positioned a minimum distance above the top surface of theworkpiece 18 to allow forworkpiece 18 to move in XY dimensions without the tip of theneedle 102 snagging on theworkpiece 18 or the threads of previous stitches. This minimum distance is referred to as the slack position PS, and has been determined to generally be in the range of 1 mm to 4 mm. Accordingly, the slack position PS changes each time a new current position P of the top of the workpiece is determined (discussed below). - Before the
needle 102 can come to rest at the slack position PS so that theworkpiece 18 can be moved, a minimum amount ofthread 101 for making the next stitch must first be played out from thespool 103. Thus, after forming a stitch as shown inFIG. 13A , the lower thread lock 114B disengages from thethread 101 and theupper thread lock 114A then engages thethread 101 so as to prevent thethread 101 from moving while theneedle 102 is removed from theworkpiece 18. Then, as seen inFIG. 13B , theneedle 102 is moved to a rest position PR above the top surface of theworkpiece 18. Generally, the rest position PR corresponds to a distance above the vertical position PW1 of the top surface of theworkpiece 18 that is equal to the amount of thread AT needed for a next stitch (i.e., PR=PW1+AT). - The
controller 70 is configured to determine the rest position PR based, in part, on a signal received from a sensor 65 (described below in relation toFIGS. 6A-6D ). More specifically, thecontroller 70 receives a signal from thesensor 65 upon the downward stroke of theneedle 102 indicating the vertical position PW1 of the top of theworkpiece 18. The controller then adds the amount of thread AT needed to the vertical position PW1 in order to obtain the rest position PR of theneedle 102. After theneedle 102 is moved to the determined rest position PR, theneedle 102 is then moved to the slack position PS (as shown inFIG. 13C ), pullingthread 101 from thespool 103, so that theworkpiece 18 can be moved in XY dimensions. - However, there is a physical limitation to how high the
needle 102 can move. As such, the situation may occur when the maximum rest position PRmax of theneedle 102 is not at a sufficiently great enough distance from the vertical position PW1 of the top of theworkpiece 18 to provide all of the amount of thread AT needed to form the next stitch (i.e., the determined rest position PR is greater than the maximum rest position PRmax). In this situation, theneedle 102 is moved up to the maximum rest position PRmax and then down to the slack position PS. Thecontroller 70 is configured to calculate a second rest position PR2, in such a situation, by the following formula: -
P R2 =P S1 +[A T−(P Rmax −P W1)]; - where PS1 is a slack position of the
needle 102 above the current position PW1 of the top of the workpiece. - Since the needle movement positions are typical calculated in terms of the current position PW of the top of the work piece, another version of the above formula is:
-
P R2 =P W1 +H S +[A T−(P Rmax −P W1)]. - Since the slack height HS is equal to the difference between the slack position PS and the position PW of the top of the work piece, yet another version of the above formula is:
-
P R2 =P W1 +[A T−(P Rmax −P S1)]. - In case the situation arises where the second determined rest position PR2 also exceeds the maximum allowed rest position PRmax, the controller is configured to repeat the above process as many times as is needed to play out the entire amount of thread needed for the next stitch.
- As shown in
FIG. 13D , once the entire amount of thread needed for the next stitch has been played out from thespool 103, theneedle 102 is brought to the slack position PS so thatworkpiece 18 may be moved in the desired XY directions. As shown inFIG. 13E , upon positioning of theworkpiece 18 so that theneedle 102 is located above the desired XY position of the next stitch, theneedle 102 is then lowered through theworkpiece 18 to the loop position PL corresponding to a distance below the current position PW2 of the top surface of theworkpiece 18 equal to the current desired loop length LL. As with the first position PW1 of the top surface of theworkpiece 18, thecontroller 70 receives a signal from thesensor 65 upon the downward stroke of theneedle 102 to form the second stitch, which indicates the current vertical position PW2 of the top of theworkpiece 18. - A preferable desired length of each loop formed on the underside of the
workpiece 18 had been found to range from 0.5 mm to 4 mm Accordingly, thecontroller 70 may be configured to take into account a desired loop length constant LLC when forming stitches. - More specifically, if the controller determined that the second amount of thread AT2 should be used as the actual amount of thread AT used in the prior stitch, then the actual loop length LL created will be the new loop length LLnew, which will be greater than desired loop length constant LLC. To adjust this longer loop length to be closer to the desired loop length constant LLC, the controller may be configured to calculate the next first amount of thread AT1next needed for the next stitch by using the following formula:
-
A T1next =L S +L LC −C 1−(2·L Lnew−2·L LC). - Similarly, next second amount of thread AT2next needed for the next stitch by using the following formula:
-
A T2next =[L S 2 +H S 2]1/2−(2·L Lnew−2·L LC). - The controller is configured to compare the first amount of thread AT1next with the second amount of thread AT2next, and use the greater of the two amounts as the actual next amount of thread AT which is to be played out from the
spool 103. - To account for the case where the
controller 70 determines (1) that the second amount of thread AT2next should be used, the controller is configured to repeat the process for increasing the length LL of next loop made as described above (when the controller uses AT2next as the actual next amount of thread AT needed to make the next stitch). - In this way, when making the next stitch, thread from the prior loop will be pulled out of the prior stitch, so as to shorten the original loop length LLnew of the prior loop so that the final loop length is roughly equal to the desired loop length constant LLC.
- Accordingly, amount of thread used to make the loop of the prior stitch (originally at twice the loop length LLnew) will be reduced to be roughly equal to the amount of thread (2·LLC) needed to make a loop of the desired length LLC (i.e., an amount of thread to extend through the top surface of the
workpiece 18 to the bottom of the loop of length LLC, and then to extend from the bottom of the loop of length LLC back up through the top surface of the workpiece 18). - Thus, the up and down movements of the
needle 102 are determined bycontroller 70 on a stitch-by-stitch basis, rather than being fixed as constant up and down movements to fixed top and bottom needle positions. This allows for greater control of the tensioning of each stitch, as well as greater control of the lengths of the thread loops created on the underside of the workpiece. Accordingly, a unique optimization of sewing stitch quality is able to be obtained. - As seen in the above described drawings, the various positions of the
needle 102 are determined based on the tip of the needle. This is because this position of the needle also corresponds to the position at which the thread is attached to the needle in the shown embodiment (i.e., where the thread passes through a hollow needle). However, the up and down movements of a solid needle with a horizontal hole (e.g., an “eye”) through which the thread passes can clearly also be determined on a stitch-by-stitch basis as above described above. In such a situation, the various positions of theneedle 102 would be determined based on the horizontal hole of the needle (e.g., the position of the “eye” of the needle). - As shown in
FIG. 5C , a further embodiment adds aforce deflection device 300 to the thread path between thespool 103, and the needle drive mechanism 301 (which includes therack slider 106,thread feed body 110, and lower thread lock 114B) and upper thread lock 112A. In this embodiment, theforce deflection device 300 is in the form of a spring. - The
needle drive mechanism 301 accelerates during the stitch cycle (i.e., the downward stroke of the needle 102), consequently pulling thethread 101 with an abruptly increased force. Thespool 103 and cartridge interface are designed to at least partially resist spinning of the spool. The sudden acceleration applied to thethread 101 by the needle drive mechanism, combined with the inertial force applied to thethread 101 by thespool 103 and the resistance to spinning ofspool 103 be design, abruptly increases the tension on thethread 101, which can lead to uneven thread tension during the stitching process. - It is desirable to try and maintain a relatively smooth and gradual, increase and decrease in thread tension. Accordingly, the
force deflection device 300 is designed to deflect or deform when theneedle drive mechanism 301 accelerates during the stitch cycle. In this way, some of the initial force applied by theneedle drive mechanism 301 to thethread 101 during the stitch cycle is transferred to theforce deflection device 300, rather than having all of that initial force transferred directly to thespool 103. - Thus, the
force deflection device 300 is able to reduce the sudden increase in tension typically experienced by thethread 101. In this way, the deformation of theforce deflection device 300 acts to absorb the peak energy applied by theneedle drive mechanism 301 to thethread 101. This creates a more uniform tension in the thread to reduce the likelihood of thread slippage in the thread feeding device (e.g., the needle drive mechanism 301), as well as to reduce the likelihood of spool over-spinning and over-pulling thethread 101. - In the particular embodiment of
FIG. 5C , thespring 300 is placed in the thread path between thespool 103 and athread guide 302, which serves to guide the thread from thespool 103 into theupper thread lock 114A and theneedle drive mechanism 301. As theneedle drive mechanism 301 accelerates downward, thethread 101 is pulled off thespool 103. This creates tension in thethread 101 as thespool 103 resists spinning, primarily from inertia (as well as inherent friction and friction by design in the spool/cartridge interface). As the tension in thethread 101 increases, thespring 300 further deflects in a downward motion. - In this embodiment, the
spring 300 is designed as a cantilever beam with a stiffness that is optimized to operate within the range of needle drive acceleration and amount of thread on spool (the diameter of thread on the spool affects spool inertia, from engineering theory). However, theforce deflection device 300 could take the form of a coiled spring which deforms by compressing when theneedle drive mechanism 301 accelerates downward. In other words, the exact form of theforce deflection device 300 is not important, so long as it is designed to deform to absorb some of the initial force applied by theneedle drive mechanism 301 to thethread 101. - The
force deflection device 300 should be optimized to operate within the range of needle drive acceleration, amount of thread on the spool, and friction in the spool/cartridge interface. It has been determined that the initial force applied by the needleddrive mechanism 301 to thethread 101 is in the range of 10 to 100 g-force, with around 50 g-force being a commonly applied initial force. Thus, theforce deflection device 300 best serves its purpose when designed to deform under such an applied force range. As such, the material used to make theforce deflection device 300 can be a metal, a rubber, a plastic, or any other material with an elastic property such that it will deform when 10 to 100 g-force is applied, and then return to its initial shape when theneedled drive mechanism 301 no longer applies a feeding force to thethread 101. To address the commonly applied initial force of 50 g-force, the material used to make theforce deflection device 300 might be chosen such that thedeflection device 300 only deforms when at least 50 g-force is applied thereto. - Furthermore, while the usefulness of the
force deflection device 300 has been explained in the context of feeding thread for a sewing or embroidery machine, theforce deflection device 300 has applicability beyond this context. More specifically, theforce deflection device 300 can be applied to any device or process which serves to feed, pull, draw, or otherwise remove a material from a spool. For example, theforce deflection device 300 could be applied to a situation where rope or chain material is to be fed from a spool. All that would be required is to adjust the force range in which theforce deflection device 300 deforms to absorb the initial feed force. - A workpiece embroidered by the single-thread sewing device described above will further require a separate means for permanent retention of the stitches in the workpiece. This may be accomplished by separate application of an adhesive to secure the thread loops to each other or to the underside of the workpiece.
- Employment of the described mechanism can be further extended, in principle, to sewing by the lockstitch method, with addition of a second thread and accompanying stitch interlocking mechanism (i.e., rotary hook) on the underside of the workpiece (not shown).
- As shown in
FIGS. 6A-6D , disclosed is a detection device and method therefor, comprising a sensor positioned to detect the physical movement of aneedle drive mechanism 301 in a sewing apparatus. As shown in the embodiment, theneedle drive mechanism 301 includes moving mechanisms of thethread feed mechanism 100 as described above (seeFIGS. 5A-5C ), such as thethread feed body 110 and thepresser foot 118. While the embodiments described herein show exemplaryremovable cartridges 100 configured to allow eachneedle drive mechanism 301 to move while the corresponding fixedcartridge 100 is stationary, it will be understood that thedetection mechanism 60 can be used withsewing apparatuses 1 in which where theentire cartridge 100 moves with theneedle drive mechanism 301, as shown in U.S. Pat. Nos. 6,729,253 and 6,729,254 (the entirety of each of which is incorporated by reference herein). - In one
embodiment lever 63, is added underneath theembroidery deck 61. Thelever 63 is able to pivot. When theneedle drive mechanism 301 moves downward during the downward stroke and contacts thelever 63, the resulting downward movement of thelever 63 actuates asensor 65 such as a mechanical switch or photo interrupter. From this actuation, the position of theneedle 102 is known. Depending on the configuration of thelever 63 andsensor 65, the needle position can be detected with high precision. - A
drive mechanism 24 can be, for example, a steady drive motor such as aDC drive motor 24. However, in anembroidery machine 1 using a variable or intermittent drive mechanism 24 (such as astepper motor 24 for driving the needle drive mechanism 301), thestepper motor 24 can lose position if subjected to too high of a load. If this occurs, the position of theneedle 102 may no longer be known if operating in open loop control. This can result in significant degradation of stitch quality. - A lever is mounted underneath the
embroidery deck 61 in the configuration of a cantilever beam as shown in the embodiment ofFIGS. 6 A-D, thereby creating a closed loop system. The lever is attached to thedeck 61 using ahinge 64 such as a piece of plastic, metal, or any other deformable material that meets the functional requirements of thedetection mechanism 60. It will be noted that embodiments of thedevice 60 include embodiments where elements such as thelever 63, hinge 64 andneedle plate 62 are each separately incorporated into the deck. Also, one or more of these elements can be unitarily formed as parts of thedeck 61, as for example, by a one-piece injection moldeddeck 61 including thelever 63, hinge 64 andneedle plate 62. - The up position is shown in
FIG. 6A . As theneedle drive mechanism 301 moves downward, thepresser foot 118 contacts theworkpiece 18, which in turn contacts theneedle plate 62, resulting in the downward pivot of thelever 63. Theneedle plate 62 positioned on thelever 63, such that the downward motion of thepresser foot 118 on aworkpiece 18 causes theworkpiece 18 to contact theneedle plate 62 so that thelever 63 contacts thesensor 65, shown as a mechanical switch. In the down-most position of the lever 63 (shown inFIG. 6B ), thesensor 65 is actuated and thelever 63 contacts thestop 66, which stops or substantially stops the downward motion of thelever 66. With thestop 66, thelever 66 is unable to over-travel, thus preventing wear and possible damage to theswitch 65. It will be noted that while the embodiment shows theneedle plate 62 is attached to thelever 63, the device could be configured in any number of ways to affect alever 63 and/orneedle plate 62 to actuate asensor 65. - In another embodiment, instead of the
lever 66 contacting amechanical switch 65, a flag could be attached to thelever 63 such that thelever 66 actuates a photo interrupter (not shown). Thesensor 65 can comprise an emitter such as a light source and a detector such as photodiode. A flag can be positioned on thelever 63 such that it interrupts a signal between the emitter and the detector, for example, a light signal to the photodiode. - In each of the embodiments, the distances from the pivot or hinge 64 to the
switch 65,needle plate 62, and stop 66 can be optimized for range of motion and force. - As explained above, depending on the configuration of the
lever 63 andsensor 65, the needle position can be detected with high precision. At least one of thepivot point 64 for thelever 63, thesensor 65, and thestop 66 can be positioned to optimize at least one of a range of motion of deflection as well as a force. Thedevice 60 can further be configured such that at least one of thepivot point 64, thesensor 65, and thestop 66 is positioned to optimize at least one of the desired qualities of the sewing apparatus. Such desired qualities may include reduced wear on thedevice 60 from repeated operation, as well as stitch delivery from the needle mechanism to theworkpiece 18. For example, the force on theneedle plate 62 required to actuate theswitch 65 can be adjusted by shifting the position of theneedle plate 62 relative to thepivot 64. The factors for the optimizing the configuration are expressed as follows in conjunction withFIG. 6E : - FNP=((DSW/DNP)*FSW)+force contribution from hinge stiffness (assuming contribution from mass of lever and needle plate are negligible)
- θ=tan−1 (dSW/DSW)
dNP=tan(θ)*DNP
dST=tan(θ)*DST
where: -
- FNP needle plate force
- FSW=switch force
- θ=angular deflection of lever
- DNP=horizontal distance from pivot to needle plate
- DSW=horizontal distance from pivot to switch
- DST=horizontal distance from pivot to stop
- dNP=vertical deflection of needle plate
- dSW=vertical deflection of lever at switch
- dST=vertical deflection of lever at stop
- As incorporated into the
sewing apparatus 1 thesensor 65 included in the detectingmechanism 60 is configured to detect the physical movement of the needle mechanism. Thesensor 65 sends a signal to thecontroller 70, such that thesensor 65 and thedrive mechanism 24 form a closed feedback loop operable to allow the CPU 71A to track the position of theneedle drive mechanism 301 of thethread feed mechanism 100 with respect to aworkpiece 18 for the needlework during operation. - As shown in
FIGS. 6C-6D , thesewing apparatus 1 comprises a plurality of thethread feed mechanisms 100. Thedetection mechanism 60 and thedrive mechanism 33 for eachthread feed mechanism 100 form a closed feedback loop, which is operable to track the position of each of the thread feed mechanisms 100 (including the needle drive mechanism 301) with respect to aworkpiece 18 for the needlework during operation. Thesewing apparatus 1 comprises a plurality of thesensors 65. Each of the plurality ofsensors 65 are configured to detect the movement of the each of thethread feed mechanisms 100, as well as determine the position of eachneedle 102 with respect to theworkpiece 18 during operation of the sewing apparatus. - Although exemplary embodiments of the present invention and modifications thereof have been described in detail herein, it is to be understood that this invention is not limited to these precise embodiments and modifications, and that other modifications and variations may be effected by one skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. A material feeding device comprising:
a spool configured so as to rotate around an axis;
a material which is wrapped around the spool;
a material feeding mechanism which is configured to feed the material in a feeding direction, thereby unraveling the material from the spool; and
a force deflection device which is arranged between the spool and the material feeding mechanism, and is connected to the material;
wherein the force deflection device is configured to as to deform physically when the material feeding mechanism applies an initial feeding force to the material.
2. The material feeding device of claim 1 ;
wherein the material is a thread.
3. The material feeding device of claim 1 ;
wherein the force deflection device includes a spring.
4. The material feeding device of claim 1 ;
wherein the force deflection device is configured to deform physically under an applied force in the range of 10 to 100 g-force.
5. A method of feeding a material from a spool, the method comprising:
providing a spool which rotates around an axis;
providing a material which is wrapped around the spool;
applying an initial feeding force to the material so as to unravel the material from the spool; and
physically deforming a force deflection device which is connected to the material and absorbs a portion of the initial feeding force before the initial feeding force is transferred to the thread on the spool.
6. The method of claim 5 ;
wherein the material is a thread.
7. The method of claim 5 ;
wherein the force deflection device includes a spring.
8. The method of claim 5 ;
wherein the force deflection device is configured to deform physically under an applied force in the range of 10 to 100 g-force.
Priority Applications (1)
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US13/041,281 US20120222601A1 (en) | 2011-03-04 | 2011-03-04 | Method and device for absorbing initial force in a thread delivery device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US13/041,281 US20120222601A1 (en) | 2011-03-04 | 2011-03-04 | Method and device for absorbing initial force in a thread delivery device |
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US20120222601A1 true US20120222601A1 (en) | 2012-09-06 |
Family
ID=46752488
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US13/041,281 Abandoned US20120222601A1 (en) | 2011-03-04 | 2011-03-04 | Method and device for absorbing initial force in a thread delivery device |
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2491685A (en) * | 1945-12-03 | 1949-12-20 | Cecyle Mabel | Sewing machine |
US20030159424A1 (en) * | 2002-02-28 | 2003-08-28 | Kiyoshi Nakashima | Thread breakage preventing apparatus and yarn processing machine having thread breakage preventing units |
US20050199165A1 (en) * | 2004-03-15 | 2005-09-15 | Vsm Group Ab | Thread feed for a sewing machine |
US20090206191A1 (en) * | 2006-06-02 | 2009-08-20 | Saint-Gobain Glass France | Device for laying down a thin metal wire on a surface |
WO2009112221A1 (en) * | 2008-03-11 | 2009-09-17 | B.T.S.R. International S.P.A. | Device and method for the constant tension feeding of threads or yarns fed in a discontinuous way |
-
2011
- 2011-03-04 US US13/041,281 patent/US20120222601A1/en not_active Abandoned
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2491685A (en) * | 1945-12-03 | 1949-12-20 | Cecyle Mabel | Sewing machine |
US20030159424A1 (en) * | 2002-02-28 | 2003-08-28 | Kiyoshi Nakashima | Thread breakage preventing apparatus and yarn processing machine having thread breakage preventing units |
US20050199165A1 (en) * | 2004-03-15 | 2005-09-15 | Vsm Group Ab | Thread feed for a sewing machine |
US20090206191A1 (en) * | 2006-06-02 | 2009-08-20 | Saint-Gobain Glass France | Device for laying down a thin metal wire on a surface |
WO2009112221A1 (en) * | 2008-03-11 | 2009-09-17 | B.T.S.R. International S.P.A. | Device and method for the constant tension feeding of threads or yarns fed in a discontinuous way |
US20110006096A1 (en) * | 2008-03-11 | 2011-01-13 | B.T.S.R. International S.P.A. | Device and method for the constant tension feeding of threads or yarns fed in a discontinuous way |
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