JP2006102400A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sewing machine for appropriately rotate a stepping motor. <P>SOLUTION: The sewing machine comprises a presser-foot mechanism for supporting a presser-foot so as to be able to move up and down; a cutting mechanism 40 having a fixed cutter 41 and a mobile cutter 42 in the lower part of a needle plate 11; the stepping motor 13 serving as the driving source of the presser-foot mechanism 20 and the cutting mechanism 40; and a power transmission mechanism 50 for applying the rotary drive force of the stepping motor 13 to each mechanism. The power transmission mechanism includes: two rotary cams 51, 52 to be driven and rotated by the stepping motor, by which the drive force is applied to each mechanism; and an operation amount adjusting mechanism 59 which is arranged between the presser-foot mechanism and the the rotary cams so as to adjust a drive operation amount. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sewing machine including a cloth pressing mechanism.

In the case of a sewing machine having a cloth presser mechanism that presses the cloth presser against the sewing material on the needle plate, when the sewing machine has another mechanism, for example, a cutting mechanism that cuts the upper thread and the lower thread, The driving source of each mechanism was shared by one stepping motor. That is, a rotating cam that individually applies a driving force to each mechanism is prepared, and each rotating cam is simultaneously rotated by a stepping motor (see, for example, Patent Document 1).
Each rotary cam is provided with a transmission mechanism composed of an arm that swings by a cam follower and a plurality of link members, and the cloth pressing mechanism and the cutting mechanism are arranged in a predetermined order by one rotation of the stepping motor. Was configured to work with.
JP 2003-210881 A

  However, when the cloth presser is moved up and down by using the rotary cam to the cloth presser mechanism, the cloth presser cannot be lowered to a predetermined lowered position when the thickness of the sewing product is thick, As a result, there is a problem that the follower of the cam cannot move around the rotating cam via the transmission mechanism, and the rotation of the rotating cam can be hindered. In that case, since the cloth presser mechanism is configured to raise the cloth presser by further rotating the rotary cam, the cloth presser cannot be raised again, and at the same time, a cutting mechanism or the like that is interlocked. There is an inconvenience that other functions cannot be operated.

In addition, if the stepping motor is powerful, the cloth presser may be lowered and removed from the non-rotatable state, but even in such a case, the stepping motor will step out due to an increase in load, and then There is a disadvantage that the operation of each mechanism cannot be performed at the correct timing.
An object of the present invention is to smoothly perform the operation of the cloth pressing mechanism and other mechanisms connected thereto.

  The invention according to claim 1 is a cutting mechanism comprising a cloth presser mechanism that supports a cloth presser that descends onto the needle plate and holds the sewing product so as to be movable up and down, and a fixed knife and a moving knife arranged below the needle plate. A stepping motor that is a drive source for raising or lowering the cloth presser and a driving source for cutting the moving knife, and a power transmission mechanism that applies the rotational driving force of the stepping motor to the cloth presser mechanism and the cutting mechanism. The power transmission mechanism includes two rotating cams that are simultaneously driven to rotate by the stepping motor. The driving force is applied to the cloth pressing mechanism and the cutting mechanism through the rotating cams, and the cloth pressing mechanism and the driving mechanism are driven by the driving force. A configuration is adopted in which an operation amount adjusting mechanism for adjusting a driving operation amount for the cloth pressing mechanism is provided between the rotating cam and the force applying force.

In the above configuration, the cloth pressing mechanism and the cutting mechanism interlocking with the cloth pressing mechanism are provided, and the rotating cam corresponding to each mechanism is simultaneously driven to rotate by the stepping motor. Thus, while the stepping motor makes one rotation, the cloth pressing mechanism and the cutting mechanism operate in a predetermined order and at a predetermined timing, respectively.
Further, when the material to be sewn is thick, there may occur a situation in which the cloth presser does not descend to the initial lower position. In that case, adjustment is performed by the operation amount adjusting mechanism so as to reduce the driving operation amount transmitted to the cloth pressing mechanism. As a result, it is possible to avoid a state in which the follower of the cam hinders the rotation of the rotating cam, and all other operations that follow can be performed smoothly. Moreover, generation | occurrence | production of the excessive burden of a stepping motor is avoided and step-out is prevented.

According to the first aspect of the present invention, since the operation amount adjusting mechanism for adjusting the driving operation amount is provided between the cloth pressing mechanism and the rotating cam, the operation amount adjusting mechanism can be used even when the sewing product is thick. Thus, adjustment can be made to reduce the amount of driving operation transmitted to the cloth presser mechanism, and the lower position of the cloth presser can be changed and adjusted upward, thus avoiding the state where the follower of the cam hinders the rotation of the rotating cam. Therefore, it is possible to smoothly perform other subsequent operations and operations of the cutting mechanism.
In addition, it is possible to avoid the occurrence of an excessive burden on the stepping motor, prevent the step-out, and allow each mechanism to perform an operation at a desired accurate timing.

(Overall configuration of the embodiment of the invention)
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. FIG. 1 is a perspective view illustrating only a main configuration of a sewing machine 10 according to an embodiment of the present invention, and FIG. 2 is a perspective view of the main configuration of the sewing machine 10 as viewed from a direction different from FIG.
The sewing machine 10 includes a sewing machine frame (not shown) that holds or stores each component. The sewing machine frame includes a bed portion positioned at a lower portion of the entire sewing machine 10 and one longitudinal end portion of the sewing machine bed portion. A vertical body portion erected upward and an arm portion extending from the upper end portion of the vertical body portion in the same direction as the bed portion are provided. In the following description, with the sewing machine 10 placed on a horizontal plane, the direction that is horizontal and parallel to the longitudinal direction of the bed portion is defined as the Y-axis direction, and the direction that is horizontal and orthogonal to the Y-axis direction is defined as the X-axis direction. The direction orthogonal to the Y-axis direction is taken as the Z-axis direction.

The sewing machine 10 descends onto the needle plate 11 and supports a fabric presser mechanism 21 that supports the fabric presser 21 that holds the fabric to be sewn so as to be movable up and down. A cutting mechanism 40 that cuts the lower thread, a stepping motor 13 that is a driving source for lowering the cloth presser 21 and a cutting operation of the cutting mechanism 40, and a rotational driving force of the stepping motor 13 to the cloth pressing mechanism 20 and the cutting mechanism 40 And a power transmission mechanism 50 to be applied.
The sewing machine 10 also has a vertical movement mechanism for holding the sewing needle to move up and down, a hook mechanism for binding the lower thread to the upper thread inserted through the sewing needle below the needle plate, and a cloth presser mechanism 20. There are various mechanisms necessary for sewing, such as a cloth moving mechanism that moves the cloth presser 21 along the upper surface of the needle plate 11 and arbitrarily performs the needle drop position. Illustration and description thereof are omitted.

(Cloth holding mechanism)
The cloth presser mechanism 20 has a base end portion held by the cloth moving mechanism and a distal end portion thereof positioned at an arbitrary position along the XY plane, and a lower side of the cloth presser 21. A lower plate 23 that is positioned and holds the fabric with the fabric retainer 21, a retainer holding member 24 that is erected at one end of the fabric retainer 21, and a holding member 24 that is provided at the distal end of the support frame 22 and A pair of guide frames 25 that support the cloth presser 21 so as to be able to move up and down, and a swing frame that is supported by the support frame 22 so as to be swingable, and that imparts a moving force to the press holding member 24 at one end by swinging. A swing bar 26, a pressing plate 27 supported by a sewing machine frame so as to be movable up and down, and a swinging member 28 supported at the upper part of the support frame 22 so as to be swingable and having one end in contact with the lower surface of the pressing plate 27. And swing member 2 The other end portion of the other end portion of the oscillation beam 26 for vertically and a first and second link members 29, 30 to be interlocked in the same direction.

The cloth presser 21 is a rectangular frame, and the insides of the four sides are greatly opened. Needle drop is performed on the fabric held inside the opening, and sewing is performed.
Correspondingly, the lower plate 23 also has a rectangular frame portion that is approximately the same size as the cloth presser 21, and is opened large like the cloth presser 21. Furthermore, the lower plate 23 has an extending portion that extends in parallel with the short side from a portion corresponding to the middle of the long side, and is held by the cloth moving mechanism at the tip of the extending portion. And the rectangular frame part side with the front-end | tip part of the support frame 22 is positioned in the arbitrary positions along XY plane.

  The support frame 22 is disposed on the upper surface of the sewing machine bed portion, and as described above, the base end portion thereof is held by the cloth moving mechanism, and the front end portion thereof gradually moves forward from above with respect to the base end portion. It is extended to. The longitudinal direction (extending direction) of the support frame 22 is provided on the sewing machine bed portion so as to be along the Y-axis direction.

The presser holding member 24 is formed in a substantially L shape, one end of which is fixedly connected to the cloth presser 21, and the other end is supported by the guide frame 25.
The guide frame 25 is fixedly installed at the distal end portion of the support frame 22 and includes a guide groove that slidably supports the other end portion of the holding member 24. The guide frame 25 is mounted on the support frame 22 so that the guide groove extends along the Z-axis direction (vertical direction). As a result, the cloth presser 21 can move up and down with respect to the support frame 22.

  Each swing rod 26 is provided so as to sandwich the support frame 22, and is supported by the support frame 22 in a state substantially along the Y-axis direction. Further, each swing rod 26 is supported by the support frame 22 so as to be swingable about an axis along the X-axis direction at an intermediate portion in the longitudinal direction, and one end portion for swinging is supported by the guide frame 25. Is inserted into a through hole provided in the other end portion of the presser holding member 24 supported by. Therefore, when the one end of the swing bar 26 moves up and down due to the swing of the swing bar 26, the cloth presser 21 also moves up and down via the press holding member 24. Further, each swing bar 26 is always urged in the direction in which the cloth presser 21 moves upward by a torsion coil spring (not shown) at the shaft support portion.

The pressing plate 27 is a rectangular flat plate, and includes a support shaft 27a that is fixedly erected vertically at the center of the upper surface thereof. The support shaft 27a has a round bar shape and is inserted into a cylindrical metal bearing 32 fixedly mounted on the sewing machine frame, and the pressing plate 27 is supported by the support shaft 27a so as to be movable up and down along the Z-axis direction. ing.
Further, the upper end portion of the support shaft 27a protrudes upward from the metal bearing 32, and pins 27b are provided on both ends in the radial direction of the upper end portion of the support shaft 27a. Each pin 27a is engaged with the power transmission mechanism 50 to receive a downward pressing force input.

The swing member 28 is disposed on the support frame 22 in a state along the Y-axis direction. The swinging member 28 is supported by the support frame 22 so as to be swingable about the axis along the X-axis direction at the middle portion in the longitudinal direction, and one end portion that moves up and down by the swinging is the lower surface of the pressing plate 27. It is the arrangement | positioning contact | abutted to the center part.
On the other hand, the other end of the swing member 28 is connected to the other end (the end opposite to the cloth presser 21) of each swing bar 26 through two link bodies 29 and 30. Since the other end of each swing rod 26 is biased downward by a torsion coil spring, the other end of the swing member 28 is also biased downward via the two link bodies 29 and 30. As a result, the one end portion of the swing member 28 is biased upward with the elasticity of the torsion coil spring, and as a result, the pressing plate 27 always maintains a state of being pushed upward.
The first link body 29 described above is swingably supported by the support frame 22, and the second link body 30 includes the swing end portion of the first link body 29 and the other end of the swing member 28. Connected to the department. Further, the swinging end portion of the first link body 29 is connected to the other end portion of the swinging rod 26 by a tension spring 31 so as to come into pressure contact therewith. The tension spring 31 is stronger than the torsion coil spring described above. When the swing end of the first link body 29 swings upward against the torsion coil spring, the other end of the swing rod 26 also It can be pulled upward.

The cloth presser mechanism 20 is normally urged in a direction in which the swing bar 26 pulls the cloth presser 21 upward by a torsion coil spring. That is, unless an external force is applied, the cloth presser 21 and the lower plate 23 are maintained in a separated state.
Further, when the support shaft 27 a of the pressing plate 27 is pressed downward by the power transmission mechanism 50, one end portion of the swinging member 28 is lowered and the other end portion is raised, via the link members 29 and 30. The other end of the swing rod 26 is also pulled upward. Thereby, the cloth presser 21 is pressed downward, and the cloth is held between the cloth presser 21 and the lower plate 23.

(Cutting mechanism)
The cutting mechanism 40 is disposed below the needle plate 11 in the sewing machine bed portion. FIG. 3 is a perspective view of the cutting mechanism 40 as viewed from below the needle plate 11. In FIG. 3, reference numeral 12 indicates a needle hole formed in the needle plate 11.
The cutting mechanism 40 cuts the upper thread and the lower thread with the fixed blade by rotating with a fixed knife 41 that is fixedly mounted on the lower surface of the needle plate 11 with the cutting edge facing the vicinity of the needle hole 12. A moving knife 42, a swing link body 43 to which a reciprocating swing force is applied by the power transmission mechanism 50, and a follower link body supported on the lower surface side of the needle plate 11 so as to swing together with the swing link body 43. 44, and a connecting link body 45 that connects the moving knife 42 and the driven link body 44.

The moving knife 42 is rotatably supported on the lower surface side of the needle plate 11 with a stepped screw 46 as a support shaft, and the needle plate 11 can pass under the needle hole 12 during the reciprocating rotation. Located on the bottom surface.
Immediately after the end of sewing, the upper thread passes from the supply source through the sewing needle, and further engages with the shuttle mechanism through the needle hole 12 of the needle plate 11, folds back, and then sews to the fabric through the needle hole 12 again. It is attached. Further, the lower thread is fed out from a bobbin which is a lower thread supply source inside the hook, is entangled with the upper thread which is folded under the needle plate 11, and is sewn to the fabric through the needle hole 12. . In other words, immediately below the needle hole 12, there are three threads: an upper thread from the sewing needle to the hook, an upper thread from the hook to the cloth, and a lower thread from the hook to the cloth. Become.
In this state, in order to remove the cloth after the sewing from the sewing machine 10, it is necessary to cut only the lower thread and one upper thread. In particular, for the upper thread, it is necessary to cut only the upper thread from the hook to the fabric in order to secure the remaining length.
That is, the moving knife 42 needs to select and cut two predetermined yarns out of the three yarns just below the needle hole 12. On the other hand, the arrangement order of the three threads is always constant at the position directly below the needle hole 12 due to the arrangement of the hooks. For this reason, in the forward rotation Tf that is the forward path of the reciprocating rotation, a so-called yarn separation operation is performed in which the pointed portion 42a is selected so that only the upper thread that is not cut is wound inside the rotation center, The two remaining in the backward rotation Tb that becomes the return path are captured and wound by the pointed portion 42b and carried to the cutting edge of the fixed knife 41 for cutting.

The swing link body 43 is supported on the lower surface of the needle plate 11 so as to be rotatable by a step screw 47 at an intermediate portion in the longitudinal direction. One end of the swing link body 43 is connected to one end of a power transmission rod 54 dictated by the power transmission mechanism 50, and the swing link body 43 is moved forward and backward along the Y-axis direction of the power transmission rod 54. Is rocked.
At the other end of the swing link body 43, a long hole 43a is formed along the arc direction centering on the stepped screw 47, and a set screw 48 is inserted into the long hole 43a so that the driven link body 44 and the swing link are connected. The body 43 is connected.

  One end of the driven link body 44 in the longitudinal direction is supported on the lower surface of the needle plate 11 together with the swing link body 44 by a step screw 47 so as to be rotatable. 43 is connected through a long hole 43a. Further, the other end portion in the longitudinal direction of the driven link body 44 is connected to one end portion of the connection link body 45. Further, the other end portion of the connecting link body 45 is connected to the moving knife 42.

  Therefore, when the set screw 48 is fastened, the driven link body 44 swings integrally with the swing link body 43, and the power transmission rod 54 moves forward (moving direction F) or moves backward along the Y-axis direction. In accordance with (movement direction B), the moving knife 41 is moved forward and backward Tf toward the needle hole 12 via the transmission link body 45 or backwardly rotated Tb from the needle hole 12 side.

Further, by loosening the set screw 48, the driven link body 44 can swing separately from the swing link body 43 within the range of the length of the long hole 43a. It is possible to fix the screw 48 in an appropriate position by adjusting it and fastening the set screw 48 again.
Since the oscillating link body 43 is connected to the power transmission rod 54, the oscillating link body 43 oscillates only within a certain angle range according to the forward or backward stroke of the power transmission rod 54, but the driven link body 44 has a set screw. Since the angle can be adjusted with respect to the swing link body 43 by the 48 and the long hole 43a, the angle range for performing the use does not change, but the rotation start position and end position can be adjusted. Thereby, it is possible to adjust the start position and the end position of rotation when cutting the moving knife 42 (actually, the return position because it is reciprocally rotated), and accordingly, the needle hole of the moving knife 42 is adjusted. It is possible to adjust the 12 passage timing, that is, the cutting timing.

(Power transmission mechanism)
As shown in FIGS. 1 and 2, the power transmission mechanism 50 includes first and second rotary cams 51 and 52 that are simultaneously driven to rotate by the stepping motor 13, and the output of the stepping motor 13 according to the first rotary cam 51. A first roller member 53 that orbits around the shaft 13a, a power transmission rod 54 that transmits power for cutting to the cutting mechanism 40, and the other end that supports the first roller member 53 at one end. A first lever member 55 that is connected to the power transmission rod 54, a second roller member 56 that orbits around the output shaft 13a of the stepping motor 13 in accordance with the second rotating cam 52, and a first portion at one end. A second lever member 57 that supports the second roller member 56 and swings in accordance with the circular movement of the second roller member 56 is connected to the second lever member 57 by a set screw 58 and swings together with the second lever member 57. The line A long link connecting the driven link body 59, a pair of arm members 60, 61 for pressing the pin 27b of the cloth presser mechanism 20 by a swinging operation, and the swinging end portion of the driven link body 59 and the arm member 60. And a power transmission plate 62.

The first roller member 53 is disposed in the guide groove of the first rotating cam 51 that is a groove cam, and around the output shaft 13 a of the stepping motor 13 along the groove according to the rotation of the first rotating cam 51. Move around.
The first lever member 55 is pivotally supported by the sewing machine frame at a middle position in the longitudinal direction in a state where the longitudinal direction of the first lever member 55 is substantially along the Z-axis direction. The first lever member 55 is pivotally supported by an axis along the X-axis direction, and the first roller member 53 located at one end moves substantially along the Y-axis direction by a circular motion. As a result, the first lever member 55 swings in accordance with the movement of the first roller member 53, and an advancing / retreating movement force substantially along the Y-axis direction is applied to the power transmission rod 54 connected to the other end. To do.

The power transmission rod 54 is arranged in a state in which the longitudinal direction is generally along the Y-axis direction in the sewing machine bed portion. For this reason, the power transmission rod 54 moves forward and backward along its longitudinal direction by the swing of the first lever member 55. By the forward movement (moving direction F) in the forward / backward movement, the moving knife 42 is moved forward through the swing link body 43 of the cutting mechanism 40 (rotation for selecting so as to wind only one upper thread). The moving knife 42 is moved backward Tb (rotation for capturing and cutting the other upper thread and lower thread) by the backward movement (moving direction B) in the forward / backward movement.
A sensor 64 is provided in the vicinity of the power transmission rod 54 to detect whether the power transmission rod 54 is in the forward position or the backward position.

The two arm members 60 and 61 are both fixedly connected simultaneously to a support shaft 66 rotatably supported on the sewing machine frame above the cloth presser mechanism 20, and the two arm members 60 and 61, The support shaft 66 and the support shaft 66 swing together.
Further, the swinging end portion of each arm member 60, 61 extends in the radial direction of the circle centering on the support shaft 66 and along the Y-axis direction, and the pressing plate 27 of the cloth pressing mechanism 20 described above is provided. It is located above each pin 27b to be moved up and down. That is, when the swinging end portions of the arm members 60 and 61 are lowered by the swinging, the arm members 60 and 61 come into contact with the pins 27b, and the cloth presser 21 presses the fabric by lowering the pressing plate 27.

  One arm member 60 has an input piece 60a, to which the swing driving force is input, extending in the Z-axis direction in the radial direction centering on the support shaft 66, separately from the swing end contacting the pin 27b. It is installed. One end of a power transmission plate 62 is connected to the input piece 60a, and the input piece 60a is swung along the Y-axis direction. Thereby, each arm member 60 and 61 whole rocks.

  The power transmission plate 62 is long and is disposed along the Y-axis direction in the sewing machine arm portion. As described above, since the other end of the power transmission plate 62 is connected to the swinging end of the driven link body 59, the power transmission plate 62 advances along the longitudinal direction by the swing of the driven link body 59. The arm members 60 and 61 are oscillated by moving (moving direction f) and moving backward (moving direction b). That is, at the time of the backward movement, each arm member 60, 61 swings in the direction in which the pin 27b of the cloth pressing mechanism 20 is pressed, and presses the cloth pressing 21. Further, at the time of forward movement, the arm members 60 and 61 swing in a direction away from the pin 27b of the cloth presser mechanism 20, and the cloth presser 21 is moved upward from the pressed state.

The second roller member 56 is disposed in contact with the outer periphery of the second rotating cam 52, and moves around the output shaft 13 a of the stepping motor 13 according to the rotation of the second rotating cam 52. The second roller member 56 is tensioned so as to always come into contact with the outer periphery of the second rotating cam 52 by a tension spring 67 provided on the driven link body 59.
The second lever member 57 is formed in a substantially L shape, and is pivotally supported on the sewing machine frame by a support shaft 65 at a bent portion thereof. The second lever member 57 is pivotally supported by an axis along the X-axis direction, and when the second roller member 56 located at one end moves substantially along the Z-axis direction by the circular motion, The end is bent so as to move approximately along the Y-axis direction.

FIG. 4 is an exploded perspective view in which the second lever member 57 and the driven link body 59 are disassembled from the connected state. The angle between the second lever member 57 and the driven link body 59 can be adjusted between each other, thereby constituting an operation amount adjusting mechanism for adjusting the driving operation amount with respect to the cloth pressing mechanism 20.
The driven link body 59 is supported on the sewing machine frame so as to be rotatable by the support shaft 65 together with the second lever member 57 at one end portion in the longitudinal direction, and a circle centering on the support shaft 65 is provided in the middle portion in the longitudinal direction. An arc-shaped long hole 59a is formed. Further, the other end in the longitudinal direction of the driven link body 59 is connected to the other end of the power transmission plate 62.

  For this reason, when the fastening screw 58 is fastened, the driven link body 59 swings integrally with the second lever member 57, and the power transmission plate 62 moves forward (moving direction f) or retracts along the Y-axis direction. In accordance with the movement (movement direction b), the arm members 60 and 61 are swung to switch the cloth presser 21 up and down.

  Further, by loosening the fastening screw 58, the driven link body 59 can swing separately from the second lever member 57 within the range of the length of the long hole 59a, and is appropriately relative to the second lever member 57. It is possible to adjust the relative angle of the follower link body 59 with respect to the appropriate second lever member 57 by re-tightening the fastening screw 58 by performing an appropriate angle adjustment.

FIG. 5 is an explanatory diagram for explaining a change in the amount of movement of the pressing plate 27 by adjusting the angle of the driven link body 59 with respect to the second lever member 57.
That is, when the follower link 59 is adjusted to the angle shown by the solid line in FIG. 5 with respect to the second lever member 57, the gap between each arm member 60, 61 and the pin 27b becomes d2, and the two-dot chain line in FIG. When the follower link 59 is angle-adjusted, the gap between each arm member 60, 61 and the pin 27b becomes d1.
On the other hand, since the swing stroke of the second lever member 57 is constant even when the angle is adjusted, as described above, the size of the gap between each arm member 60, 61 and the pin 27b is adjusted by the angle adjustment. By doing so, it is possible to adjust the push-in amount of the pin 27b and the pressing plate 27 in the downward direction.

Next, the first and second rotating cams 51 and 52 will be described. FIG. 6 shows a timing chart of the thread trimming operation of the cutting mechanism 40 driven by the rotary cams 51 and 52 and the lifting / lowering operation of the cloth presser 21 of the cloth presser mechanism 20. In FIG. 6, the upper line indicates the operation of the cloth presser mechanism 20, and the vertical axis indicates the height of the cloth presser 21. In FIG. 6, the lower line indicates the operation of the cutting mechanism 40, and the vertical axis indicates the amount of rotation angle in the forward rotation direction.
In FIG. 6, the horizontal axis indicates the amount of rotation angle of the stepping motor 13, and FIG. 6 illustrates one rotation of the stepping motor 13 from the angle immediately before the start of the cutting operation.

As described above, the first rotating cam 51 is a groove cam, and the first rotating cam 51 guides the first roller member 53 along a circumferential locus centering on the output shaft of the stepping motor 13. At the same time, some of them are guided along a locus that is recessed toward the inside of the circle. That is, the guide groove of the first rotating cam 51 is formed in a substantially heart shape.
The first rotating cam 51 does not swing the first lever member 55 in the section along the circumference, but swings only in the recessed section (hereinafter referred to as a concave section).
The concave section of the first rotating cam 51 changes gradually from the circumferential section, gradually approaches the output shaft 13a of the stepping motor 13, and is closest to the output shaft 13a just in the middle of the concave section. And if it passes there, it will leave | separate from the output shaft 13a, and will return to a circumferential area gradually.

Due to the shape of the first rotating cam 51, when the first roller member 53 reaches the concave section, the first lever member 55 is driven until it reaches the position closest to the output shaft (hereinafter referred to as the bottom). The transmission rod 54 is moved forward, and at the same time, the moving knife 42 of the cutting mechanism 40 is rotated forward Tf. Thereby, the moving knife 42 selects and captures only one upper thread hanging from the needle hole 12.
Furthermore, when the first roller member 53 passes through the bottom of the concave section, the first lever member 55 moves the power transmission rod 54 backward until it reaches the circumferential section, and at the same time, the moving knife 42 of the cutting mechanism 40 is moved. Reverse rotation Tr is performed. As a result, the moving knife 42 captures the other upper thread and lower thread hanging from the needle hole 12 and carries them to the fixed knife 41 for cutting.

The second rotating cam 52 is moved to a distance from the output shaft 13a of the stepping motor 13 at each position on the outer peripheral surface by causing the second roller member 56 to contact the outer peripheral surface and moving according to the outer peripheral shape. A function of swinging the second lever member 57 with a corresponding movement amount is provided.
The second rotating cam 52 is mounted on the output shaft 13a of the same stepping motor 13 as the first rotating cam 51, and is rotated simultaneously with the first rotating cam 51, so that the cutting operation and the cloth pressing operation are performed. I try to interlock.
Specifically, as shown in FIG. 6, the second rotary cam 52 is moved so that the cloth presser 21 is raised after the cutting mechanism 40 performs the yarn spreading operation and the yarn cutting operation by the first rotary cam 51. The outer periphery shape is set. That is, the second rotating cam 52 is composed of two sections with a radius large and small with the output shaft 13a as the center, and the boundary section from the section with the large radius to the section with the small radius is interlocked. Provided immediately after the concave section (downstream in the rotational direction), a section with a small radius continues for approximately half a circumference of the stepping motor 13, and then transitions to a section with a large radius through the boundary section.

Due to the shape of the second rotating cam 52, when the cutting mechanism 40 has not yet performed the yarn separation and cutting, the second roller member 56 is in contact with the section having a large radius, and the second lever member 57. And the power transmission plate 62 is moved in the backward direction b by the driven link body 59. Accordingly, each arm member 60, 61 presses the pin 27b, and the cloth presser mechanism 20 maintains the presser of the cloth presser 21.
Further, as soon as the cutting operation is completed by the first rotating cam 51, the second roller member 56 passes through the boundary section from the section with the larger radius to the section with the smaller radius, and the second lever member 57 and the swinging movement are performed. The link body 59 swings to move the power transmission plate 62 in the forward direction f. Accordingly, the arm members 60 and 61 rotate upward to release the pressing of the pin 27b, and the cloth presser mechanism 20 raises the cloth presser 21 to release the cloth presser state.
From the above configuration, the power transmission mechanism 50 works to link the cloth pressing mechanism 20 and the cutting mechanism 40.

  The output shaft 13a of the stepping motor 13 is equipped with a rotating plate 68. The rotating plate 68 is cut out in an arc shape concentric with the output shaft, and whether or not the stepping motor 13 is currently at the cutting start angle or end angle by the sensor 69 that detects the presence of the rotating plate, or It is detected whether or not the rotation is properly performed without causing the non-rotatable state.

(Description of sewing machine operation)
In the sewing machine 10 having the above-described configuration, the sewing needle is moved up and down by the vertical movement mechanism, and the cloth on the upper surface of the needle plate 11 is sewn by binding the upper needle thread by the shuttle mechanism.
During sewing, the stepping motor 13 is stopped at the angle of the origin in FIG. When the sewing is completed, the stepping motor 13 starts to rotate. Thereby, in the 1st rotation cam 51, the 1st roller member 53 is guided to a recessed area, and the moving knife 42 of the cutting mechanism 40 is advanced and rotated toward the rotation direction Tf until it reaches the bottom. As a result, a portion of the upper thread that is close to the thread supply source is captured by the moving knife 42, and thread separation is performed. Further, when the first roller member 53 is removed from the bottom of the concave section, the moving knife 42 rotates backward in the rotation direction Tb, and a portion near the lower thread and upper thread fabric is cut.
During this time, in the second rotating cam 52, the second roller member 56 is in contact with the section having a large radius, and the state where the power transmission plate 62 has moved in the backward direction b is maintained. Maintain 21 descent.

Further, when the stepping motor 13 rotates, the first roller member 53 moves from the concave section of the first roller member 53 to the circumferential section, and the moving knife waits at the original position after retreating.
On the other hand, the second roller member 56 of the second rotating cam 52 moves to a section with a smaller radius, the power transmission plate 62 is moved in the forward direction f, and the cloth presser mechanism 20 raises the presser foot 21 and presses it. Release the state.

Further, when the material to be sewn is thick, as shown in FIG. 5, the fastening screw 58 is loosened, and the driven link body 59 is moved from the position of the two-dot chain line to the position of the solid line with respect to the second lever member 57. And the fastening screw 58 is fastened again. FIG. 5 shows the arrangement of each configuration when the second roller member 56 is in contact with a smaller section of the second rotating cam 52 in both the solid line and the two-dot chain line.
By the above operation, the distance between each arm member 60, 61 and the pin 27b is adjusted from d1 to a wider d2. As a result, when the second roller member 56 moves from a small section to a large section of the second rotating cam 52, the push amount of the pin 27 b by the arm members 60 and 61 is reduced, and the cloth presser 21 It becomes possible to raise a lower position (position after a fall).
Therefore, the cloth presser 21 cannot reach the predetermined lower position due to the thick cloth, the second lever member 57 cannot swing, and the second rotating cam 52 rotates by the contact of the second roller member 56. This prevents the stepping motor 13 from rotating.

(Effect of embodiment)
In the sewing machine 10, since the power transmission mechanism 50 is provided with the driven link body 59 as an operation amount adjusting mechanism for adjusting the amount of pressing of the pin 27 b between the second rotating cam 52 and the pin 27 b, Even when the sewn product is thick, adjustment is performed so as to reduce the pressing amount with respect to the pin 27b, and the lower position of the cloth presser 21 can be changed and adjusted upward. This makes it impossible for the second lever member 57 to swing and prevents the second roller member 56 from interfering with the rotation of the second rotating cam 52, and other operations by the stepping motor 13, that is, The cloth presser 21 can be raised, the yarn can be separated, and the yarn can be cut smoothly by the cutting mechanism 40.
Further, it is possible to avoid generation of an excessive load on the stepping motor 13 and to prevent step-out and to cause the mechanisms 20 and 40 to perform operations at a desired accurate timing.

(Other)
In the above embodiment, the cutting mechanism 40 is driven by the single stepping motor 13 together with the cloth pressing mechanism 20, but a configuration in which the stepping motor 13 drives more mechanisms by adding a new mechanism. Alternatively, instead of the cutting mechanism 40, another mechanism, for example, a thread wiper mechanism for pulling out the upper thread after cutting from the cloth may be driven by the same stepping motor 13. Further, the number of rotating cams may be increased and more mechanisms may be driven in various orders or at various timings.

  Moreover, although the drive amount with respect to the cloth presser mechanism 20 is adjusted by adjusting the clearance gap between the arm members 60 and 61 and the pin 27b using the driven link body 59, it is not particularly limited to this. . Any configuration may be used as long as the driving amount reaching the cloth pressing mechanism 20 from the stepping motor 13 can be adjusted.

It is the perspective view which illustrated only the main structures of the sewing machine which is embodiment of invention. It is the perspective view which looked at the main structures of the sewing machine from the direction different from FIG. It is the perspective view which looked at the cutting mechanism from the lower side of the needle plate. It is the disassembled perspective view which decomposed | disassembled the 2nd lever member and the driven link body from the connection state. It is explanatory drawing for demonstrating the change of the raising / lowering movement amount of a press plate by the angle adjustment of the driven link body with respect to a 2nd lever member. The timing chart of the thread trimming operation | movement of the cutting mechanism driven by the 1st and 2nd rotation cam and the raising / lowering operation | movement of the cloth presser of a cloth presser mechanism is shown.

Explanation of symbols

10 sewing machine 11 throat plate 21 cloth presser 20 cloth presser mechanism 13 stepping motor 40 cutting mechanism 41 fixed knife 42 moving knife 50 power transmission mechanism 51 first rotary cam 52 second rotary cam 57 second lever member (operation amount adjustment) mechanism)
59 Follower link body (motion adjustment mechanism)

Claims (1)

A cloth presser mechanism that supports the cloth presser that is lowered onto the needle plate and holds the workpiece to be raised and lowered;
A cutting mechanism comprising a fixed knife and a moving knife arranged below the needle plate,
A stepping motor that is a driving source for raising or lowering the cloth presser and that is a driving source for cutting the moving knife;
A power transmission mechanism that applies a rotational driving force of the stepping motor to the cloth pressing mechanism and the cutting mechanism;
The power transmission mechanism is
Two rotating cams that are simultaneously driven to rotate by the stepping motor are provided, and a driving force is applied to the cloth pressing mechanism and the cutting mechanism through the rotating cams, and the cloth pressing mechanism and the driving force are applied thereto. A sewing machine having an operation amount adjusting mechanism for adjusting a driving operation amount for the cloth pressing mechanism between the rotating cam and the rotating cam.

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