JP2003326063A - Needle thread clamping device for sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To start sewing by delivering needle threads to necessary lengths while the ends of the needle threads guided out from sewing needles are held securely with a holder and enables knotting with stable stitches at the start of sewing by preventing breakages of needles and threads and the like at the start of sewing in a sewing machine with a thread cutting device. <P>SOLUTION: In the needle thread clamping device 10 which is arranged on a thread path to the sewing needle 18 from a thread supply source 27 and has the first stitch balancing thread tension regulator 11 that applies a very weak tension to the needle thread 17, the second stitch balancing thread tension regulator 12 that applies a desired tension to the needle thread 17 and a holding mechanism 13 for holding the end 17a of the needle thread guided out of the sewing needle 18 after it is cut off, after the end 17a of the needle thread is held with the holding mechanism 13, the application of the tension to the needle thread 17 by the second stitch balancing thread tension regulator 12 is released only for a specified space of time almost simultaneously with the start of the sewing. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle thread clamp device for a sewing machine, for example, in a sewing machine with a thread cutting device,
The present invention relates to a needle thread clamp device for a sewing machine, which ensures that the upper thread and the lower thread can be entangled at the start of sewing after thread trimming, so that the stitch at the beginning of sewing can be knotted stably.

[0002]

2. Description of the Related Art Conventionally, a sewing machine with a thread trimming device has a holding mechanism provided in the vicinity of the jaw of the sewing machine, which catches an upper thread end derived from a sewing needle after thread cutting with a wiper and pulls it out from below the sewing cloth. It is sucked and held until the next sewing starts. After thread cutting, if sewing is not started while the upper thread end is held by the holding mechanism, the needle thread will flutter or be sewn with the tip hardened, forming a so-called bird's nest. There was a fear that the value would be reduced.

[0003]

By the way, the conventional wiper is engaged by repeating engagement with a rubber engaging member provided at the suction port of the holding mechanism to regulate the stroke of the wiper cylinder. Since the member deteriorates and the standby position of the tip of the wiper is likely to be displaced, the accuracy of the standby position of the tip of the wiper is not always high. Therefore, when the wiper is operated, the tip of the wiper overruns and passes through the suction port of the holding mechanism,
The upper thread end may not be held by the holding mechanism.
If the needle thread end derived from the sewing needle is not held securely by the holding mechanism, the needle thread end will come off from the sewing needle at the beginning of sewing, making it impossible to form stitches thereafter, or at the beginning of sewing. There was a problem that a so-called bird's nest was formed.

Further, a first thread tension and a second thread tension are arranged on the thread path of the upper thread to apply tension to the upper thread. The upper thread end drawn out from the sewing needle is sucked and held by the holding mechanism, and the upstream side of the upper thread is tensioned by the first thread tensioner and the second thread tensioner, that is, the upstream side of the upper thread and If sewing is started in a state where both sides on the downstream side are constrained, when the shuttle feeds the upper thread, a phenomenon that a strong tension acts on the upper thread and the needle is bent may occur. When the sewing needle descends in a bent state, it interferes with the needle plate and breaks the sewing needle.

Further, when a tension higher than the tensile strength of the upper thread acts on the upper thread, the upper thread is broken, and there is a drawback that subsequent sewing cannot be performed. Furthermore, if the upper thread is stretched, there is a problem that the hook cannot reliably catch the upper thread.
Therefore, it is necessary that the upper thread at the start of sewing always have an appropriate degree of slack to prevent excessive tension from acting on the upper thread.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to reliably hold an upper thread end extending from a sewing needle by a retainer in a sewing machine with a thread trimming device, and to obtain a required length. An object of the present invention is to provide a needle thread clamp device for a sewing machine, which is capable of performing stable sewing without feeding needle breakage, thread breakage, etc., by feeding out the upper thread and starting sewing.

[0007]

In order to achieve the above-mentioned object, the present invention, as set forth in claim 1, is arranged on the thread path from the thread supply source to the sewing needle and has a weak tension on the upper thread. A first thread tensioner that applies a tension, a second thread tensioner that is disposed on the thread path and applies a desired tension to the upper thread, and a holding mechanism that holds the upper thread end derived from the needle after thread cutting. In the upper thread clamp device of the sewing machine, after the upper thread end is held by the holding mechanism, the second thread tensioner releases the tension applied to the upper thread for a predetermined time substantially at the same time as the start of sewing. And a control means for controlling

Here, as the yarn supply source, for example, a yarn winding in which a yarn is wound in a cone shape can be exemplified. An example of the control means is an electronic control device including a computer. In the upper thread clamp device of the sewing machine configured as described above, the tension application to the upper thread by the second thread tension is released at the same time as the start of sewing for a predetermined time. It will be possible to feed from the upstream side without resistance. Therefore, in the needle thread clamp device of this sewing machine, it is possible to prevent excessive tension from being applied to the needle thread at the beginning of sewing, and it is possible to solve the conventional problems of needle breakage and thread breakage.

According to a second aspect of the present invention, there is provided a first thread tension member which is arranged on a thread path from a thread supply source to a sewing needle and which applies a weak tension to the upper thread, and the first thread tension member on the thread path. A second thread tensioner, which is arranged on the upper thread and applies a desired tension to the upper thread, and a thread drag mechanism, which is disposed on the thread path and performs a thread drag operation for pulling up or lowering the upper thread, In a needle thread clamp device of a sewing machine having a holding mechanism for holding an upper thread end derived from a sewing needle after cutting, a control means for controlling to execute a thread drawing operation by the thread drawing mechanism at substantially the same time as the start of sewing. It is characterized by having.

In the needle thread clamp device of the sewing machine constructed as described above, since the thread plucking operation by the thread plucking mechanism is performed at substantially the same time as the start of sewing, it is necessary to form the stitch of the first stitch. The length of the upper thread can be fed out before sewing. Therefore, in the upper thread clamp device of this sewing machine, it is possible to start sewing with the required length of the upper thread being secured, and it is possible to form stable stitches immediately after the start of sewing.

According to a third aspect of the present invention, there is provided a first thread tension member which is arranged on a thread path from a thread supply source to a sewing needle and applies a weak tension to the upper thread, and the first thread tension member on the thread path. And a second thread tensioner for applying a desired tension to the needle thread, and a tip portion that can intersect the needle bar vertical movement locus, and the needle thread end derived from the sewing needle after thread cutting is provided by the tip portion. A sewing machine including a captureable wiper, and a holding mechanism that forms a suction port at a position facing the tip end portion of the wiper when the wiper is activated and sucks and holds the upper thread end captured by the wiper. In the needle thread clamp device, an engaging portion is provided on the outer peripheral portion of the suction port of the holding mechanism so as to project inward of the movement path of the tip of the wiper and in a substantially opening direction of the suction port. It is characterized by having an elastic body.

In the needle thread clamp device of the sewing machine constructed as described above, since the engaging portion of the elastic body is arranged so as to be located inside the movement locus of the tip of the wiper, when the wiper is operated, The tip portion is brought into contact with and locked by the locking portion of the elastic body. As a result, an overrun in which the tip portion of the wiper operates by passing through the suction port of the holding mechanism is prevented, and the wiper can be reliably stopped near the suction port. Therefore, the upper yarn end that is captured and moved by the tip of the wiper can be reliably guided to the suction port of the holding mechanism, and can be sucked and held.

That is, in the needle thread clamp device of this sewing machine, the needle thread end can be reliably held and sewing can be started, and the needle thread end comes out of the sewing needle at the beginning of sewing as in the conventional sewing machine. It is possible to solve the problem that a product is not formed or a bird's nest is formed at the beginning of sewing to lower the product value.

According to a fourth aspect of the present invention, there is provided the needle thread clamp device according to the third aspect of the present invention, in which the locking portion of the elastic body is at least partially downward. It is characterized in that a protruding portion is formed to face it.

In the needle thread clamp device of the sewing machine constructed as described above, since the protrusion protruding downward is formed at a part of the engaging portion of the elastic body, the tip of the wiper is After contacting the locking portion of the elastic body, it is possible to securely engage with the protrusion and prevent overrun. As a result, the upper thread end that is captured and moved by the tip of the wiper is also reliably locked by the locking portion, and can be stably held by the holding mechanism. Therefore, in the needle thread clamp device of this sewing machine, since the needle thread end is securely held by the holding mechanism, the stitches are not formed due to the needle thread exposure at the beginning of sewing and the needle thread end coming out from the sewing needle as in the conventional case. The problem of spider web formation can be solved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, a needle thread clamp device 10 of a sewing machine according to an embodiment of the present invention.
Is a first thread tensioner 11, a second thread tensioner 12, and a holding mechanism 1.
3, an electronic control unit 14 as a control unit, and a wiper 1
5 and a thread hoisting mechanism 16.

The first thread tension member 11 is for applying a weak tension to the upper thread 17 and is a thread winding source 2 which is a thread supply source.
It is arranged on the thread path from 7 to the sewing needle 18. In the first thread tension member 11, two pressing bodies 19 are superposed and pressed by a coil spring so as to be in close contact with each other. The biasing force of the coil spring is set to be relatively weak, and the upper thread 17 is sandwiched between the two pressing bodies 19 to give a weak tension.

As shown in FIG. 1, the second thread tension member 12 is a rotary tension for applying a desired tension to the upper thread 17, and is located downstream of the first thread tension member 11 and on the sewing machine 1 with a thread trimming device. Is disposed on the arm jaw 1a of the. As shown in FIG. 2, the pressing body 20 having a hole of the second thread tension member 21 is fitted and arranged in the thread tension shaft 21 and is rotatable.
The thread tension shaft 21 is a shaft in which a through hole 21a is formed in the axial direction, a split groove 21b is formed in the axial direction at one end, and a male screw 21c is formed on the outer circumference. In this embodiment, a rotary tensioner is illustrated as the second thread tensioner 12, but a normal thread tension mechanism in which two dish members are coaxially arranged may be used.

Friction members 22 made of felt are arranged on both end surfaces of the pressing body 20 so as to fit in the split grooves 21b.
A coil spring 24 is arranged between the thread tension knob 23 screwed to the male screw 21c and the one friction member 22, and the friction member 22 is pressed toward the pressing body 20. The friction members 22 are pressed in a direction in which they are in close contact with each other by the urging force of the coil spring 24 via the pressing body 20. A pin 25 is slidably fitted in the through hole 21a of the thread tension shaft 21, and one end 25a is in contact with the friction member 22. The other end 25b of the pin 25 is connected to a plunger 28 of a push type electromagnetic solenoid 26.

When the electromagnetic solenoid 26 is actuated and the plunger 28 is extended, the pin 25 moves in the through hole 21a to the right in FIG. 2, and resists the biasing force of the coil spring 24 to press the friction member 22. It is designed to press in the direction away from 20. As a result, the frictional force of each friction member 22 with respect to the pressing body 20 is released. The upper thread 17 is wound around a groove having a substantially V-shaped cross section formed on the circumferential surface of the pressing body 20, and the thread tension knob 2
By rotating 3 to adjust the pressing force of the coil spring 24, the rotational resistance of the pressing body 20 can be adjusted, and thus the upper thread 17 can be given an arbitrary tension.

As shown in FIGS. 1 and 3, the holding mechanism 1
3 is an upper thread end 17a derived from the sewing needle 18 after thread cutting.
And a suction pipe 31 joined to the clamp portion 30 in a substantially Y shape. As shown in FIG. 3 and FIG. 4, an internal space 30b is formed in the clamp part 30, and the internal space 30b is formed.
Two openings 30c and 30d are formed so as to communicate with b. The opening 30d is connected to the negative pressure source 32 via the suction pipe 31. The opening 30c is provided with the suction nozzle 3
7 and communicates with a suction port 37a formed at the tip of the suction nozzle 37. Opening 30c and internal space 30
The connecting portion with b has a conical shape and a seating surface 30e is formed. A ball 33 is arranged in the internal space 30b so as to face the seat surface 30e. The ball 33 can float in the internal space 30b when a negative pressure is generated in the internal space 30b. A clamp cylinder 34 is disposed in the internal space 30b, and a piston rod 35 of the clamp cylinder 34 is disposed so as to face the ball 33.

The suction port 37a of the suction nozzle 37 is adjacent to the arm jaw 1a and is located at a position facing the tip 15a of the wiper 15 when the wiper 15 to be described later is actuated. As shown in FIGS. 1 and 6, an annular elastic body 38 is fitted and fixed to the tip of the suction nozzle 37. In the elastic body 38, a part of the annular portion is the suction port 37.
A locking portion 38a is formed so as to project substantially in the opening direction of a. The tip of the locking portion 38a is bent downward to form a protrusion 38b. The locking portion 38a is located inside the movement trajectory of the tip portion 15a of the wiper 15, and the tip portion 15a comes into contact with the locking portion 38a when the wiper 15 operates.

As shown in FIG. 1, the wiper 15 is for catching the upper thread end 17a of the upper thread 17 drawn below the needle plate after thread cutting and drawing it out above the needle plate. And is disposed near the sewing needle 18. The wiper 15 is connected to a wiper cylinder 36, and the wiper cylinder 36 operates so as to move along a predetermined locus. The tip portion 15a of the wiper 15 is in the standby position near the holding mechanism 13 described above during standby, and when operating, once circumvents the vertical movement locus of the sewing needle 18 and turns to the left of the needle, and then intersects the vertical movement locus. The upper thread end 17a drawn from the sewing needle 18 is captured by the tip portion 15a and the thread can be wiped upward.

As shown in FIG. 5, the electronic control means 14, which is an example of the control means, is for controlling various devices arranged in the sewing machine 1 with the thread cutting device, and performs various calculations and processes. The central processing unit 40 to be executed, a ROM 41 in which a control program and various data are stored, and a RAM 42 in which data calculated by the central processing unit 40 and the like are stored.

A start switch 44, a pedal switch 45 and an angle detector 46 as input devices are electrically connected to the electronic control means 14 via an input / output interface 43. Further, in the electronic control means 14, a motor driver 49 connected to the sewing machine motor 48, a negative pressure source operating means 50 connected to the negative pressure source 32, and a clamp cylinder 34 are provided as output devices via the input / output interface 43. Clamp cylinder drive solenoid valve 5 connected
1. Thread cutting cylinder drive solenoid valve 53 connected to thread trimming cylinder 52, thread drag cylinder drive solenoid valve 55 connected to thread drag cylinder 54, wiper cylinder drive solenoid valve 56 connected to wiper cylinder 36, presser cylinder A holding cylinder drive electromagnetic valve 59 connected to 58 and an electromagnetic solenoid 26, which is an example of a pressing actuator connected to the second thread tension member 12, are electrically connected to each other. The electronic control means 14 is configured to output an operation command signal to each output device according to an input signal from each input device to control the output device.

As shown in FIG. 1, the thread drawing mechanism 16 is
The needle thread 17 is pulled up or lowered by moving up and down, and includes a rotatable wire mounting base 16a and a yarn feeding wire 16 having one end fixed to the wire mounting base 16a.
b. The other end of the yarn feeding wire 16b can be locked with the upper yarn 17, and the other end of the yarn feeding wire 16b moves up and down by the rotation of the wire mounting base 16a to pull up or lower the upper yarn 17. That is, when the other end of the yarn feeding wire 16b rises, the upper thread 17 is tensioned, and when it lowers, the tension of the upper thread 17 is reduced.

Next, the operation of this embodiment will be described. As shown in FIG. 5, when the pedal switch 45 is stepped back to instruct the electronic control means 14 to perform thread cutting, an operation command signal is output from the electronic control means 14 to the thread cutting cylinder drive solenoid valve 53. The thread cutting cylinder 52 operates and the thread cutting mechanism (not shown) cuts the upper thread and the lower thread.

Next, as shown in FIGS. 6 and 7, an operation command signal is output to the wiper cylinder drive solenoid valve 56, and the wiper cylinder 36 is operated. Wiper 15
6, as shown in FIG.
From the standby position facing the suction port 37a of the sewing machine, bypassing the vertical path of the sewing needle 18 and on the opposite side of the sewing needle (the left side of the needle in the drawing).
Move to.

Then, as shown in FIG. 7, the wiper 15
The tip portion 15a of the needle is a needle thread end 17a drawn from the sewing needle 18.
Is picked up and the yarn is wiped up by moving in the direction of arrow A. As shown in FIG. 8, the tip portion 15 a of the wiper 15 is made of an elastic material 38.
It comes into contact with the locking portion 38a and stops. At this time, the needle thread end 17a captured by the tip portion 15a is locked by the locking portion 38.
It is locked by a and is located at a position facing the suction port 37a. Since the protruding portion 38b is formed downward from the locking portion 38a, the tip portion of the wiper 15 has a protruding portion 38b.
It will not be disengaged from the locking portion 38a by being blocked by b, and therefore will not overrun. As a result, the tip portion 15a and the needle thread end 17a are reliably positioned near the suction port 37a.

When the negative pressure source operating means 50 is operated by the command from the electronic control means 14, the negative pressure of the negative pressure source 32 is supplied to the suction port 37a, and the air around the suction port 37a is sucked into the suction nozzle 37. To do. Therefore, the needle thread end 17a in front of the suction port 37a is sucked into the suction nozzle 37 together with air from the suction port 37a, passes between the ball 33 and the seat surface 30e, and is sucked into the suction pipe 31.

As shown in FIGS. 3 and 4, when an operation command signal is output from the electronic control means 14 to the clamp cylinder drive electromagnetic valve 51, the piston rod 35 of the clamp cylinder 34 expands to press the ball 33. To do. As a result, the upper thread end 17a is sandwiched and held between the ball 33 and the seat surface 30e.

As shown in FIGS. 2 and 5, in the sewing machine with a thread trimmer 1 according to the first embodiment, when an operator operates the start switch 44 to start sewing, an operation command signal is sent to the electronic control means 14. Output to the motor driver 49 via the input / output interface 43 and the sewing machine motor 48 starts rotating.

At about the same time, the operation command signal is also transmitted to the electromagnetic solenoid 26 for a predetermined period of time, and the electromagnetic solenoid 26 operates to cause the plunger 2 of the electromagnetic solenoid 26 to operate.
8 stretches. The friction member 22 is moved by being pressed by the pin 25, and the force of the coil spring 24 applied to each friction member 22 via the pressing body 20 is removed.
The rotation resistance of is released. As a result, the upper thread 17 is fed out from the second thread tension 12 side without resistance as the sewing needle 18 descends, and the upper thread 17 is not subjected to excessive tension and the stitch of the first stitch is It is formed.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. In the figure, S1, S2, ... Show the numbers in the processing order (steps). First, in S1, it is determined whether or not there is a sewing start request from the operator. That is,
The electronic control unit 14 determines whether or not the start switch 44 of FIG. 5 has been operated. If there is a sewing start request, the process proceeds to S2, the clamp cylinder 34 is turned off, and the holding of the needle thread end 17a by the holding mechanism 13 is released.

Next, in S3, the electromagnetic solenoid 26 is operated to release the clamping of the upper thread end 17a by the two pressing bodies 20, and the tension application by the second thread tensioner 12 is released.
Next, in S4, the sewing machine motor 48 is rotated to perform sewing, and in S5, it is determined whether the sewing machine has rotated to a predetermined phase.

Here, the predetermined phase is at least the phase after the loop of the upper thread 17 passes through the shuttle (not shown), for example, the phase where the sewing needle 18 is in the upper position. The phase can be recognized by detecting the rotation of the sewing machine motor 48 by the angle detector 46 and transmitting it to the electronic control means 14.

If the predetermined phase has not been reached, the process returns to S4 to continue sewing. When the predetermined phase is reached, the process proceeds to S6, the electromagnetic solenoid 26 is turned off, and the coil spring 2
The urging force of 4 acts on the pressing body 20 to give the upper thread 17 an appropriate tension. In the subsequent sewing, the upper thread 17 to which an appropriate tension is applied by the second thread tensioner 12 is entangled with the lower thread, and the thread is tightened to form a stitch.

Further, as shown in FIGS. 1 and 5, the second
In the sewing machine with thread trimmer 1 according to the embodiment, when the operator operates the start switch 44, an operation command signal is transmitted from the electronic control means 14 to the motor driver 49, and the sewing machine motor 48 starts rotating.

At about the same time, an operation command signal is transmitted to the thread drawing cylinder drive solenoid valve 55 via the input / output interface 43, and the thread drawing cylinder 54 is operated. As a result, the wire mounting base 16a rotates, and the other end of the yarn feeding wire 16b moves up and down, so that the upper thread 17 is fed from the thread winding 27. As a result, the upper thread 17 is formed with the first stitch without applying excessive tension.

According to the sewing machine with the thread trimming device of the above-described embodiment, the upper thread 1 by the second thread tensioner 12 is almost simultaneously with the start of sewing.
The tension applied to the thread 7 is released or the thread threading mechanism 16 is actuated to reel out the needle thread 17 to relieve the tension of the needle thread 17, so that excessive tension is prevented from acting on the needle thread 17 at the start of sewing. Therefore, problems such as needle breakage and thread breakage can be solved.

The needle thread clamp device of the sewing machine of the present invention is not limited to the above-described embodiment, but can be appropriately modified and improved.

In addition, the thread supply source, the upper thread, the first thread tension, the second thread tension, the sewing needle, the holding mechanism, the upper thread clamp device, the control means, the thread dragging mechanism, which are exemplified in the above-described embodiment,
The material, shape, size, form, number, location, etc. of the wiper, elastic body, etc. are arbitrary and are not limited as long as the present invention can be achieved.

[0043]

As described above, according to the present invention, as described in claim 1, substantially simultaneously with the start of sewing, the tension application to the upper thread by the second thread tension is released for a predetermined time. With this configuration, the needle thread of the length necessary for forming the first stitch can be fed from the upstream side without resistance. Therefore, in the needle thread clamp device of this sewing machine, excessive tension does not act on the needle thread at the beginning of sewing, and needle breakage and thread breakage do not occur.

Further, according to the present invention, as described in claim 2, since the thread plucking operation by the thread plucking mechanism is performed at substantially the same time as the start of sewing, the stitch of the first stitch is formed at the start of sewing. The upper thread of the length required to do this can be fed out. Therefore, in the needle thread clamp device of this sewing machine, it is possible to start sewing with the required length of the needle thread secured, and to form stable stitches immediately after the start of sewing.

Further, according to the present invention, as described in claim 3, since the elastic body is arranged so that the locking portion of the elastic body is located inside the movement locus of the tip of the wiper, the wiper is arranged. During operation, the tip of the wiper abuts on and is locked by the locking portion of the elastic body. As a result, the tip end portion of the wiper is prevented from operating by passing through the suction port of the holding mechanism, and it is possible to reliably stop the wiper in the vicinity of the suction port. Further, the needle thread end which is captured and moved by the tip of the wiper can be surely guided to the suction port and sucked and held by the holding mechanism. Therefore, in the needle thread clamp device of this sewing machine, it is possible to reliably hold the needle thread end and start sewing, and at the beginning of sewing as in the conventional sewing machine, the needle thread end comes out of the sewing needle and the stitch The problem that the product value is not formed or a bird's nest is formed at the beginning of sewing is solved.

Further, according to the present invention, as described in claim 4, since the protrusion is formed downward on a part of the engaging portion of the elastic body, the tip of the wiper is activated when the wiper is operated. After the portion comes into contact with the locking portion, the portion engages with the protruding portion to reliably prevent overrun of the wiper. As a result, the upper thread end that is captured by the tip of the wiper and moves,
It is securely locked to the locking portion and stably held by the holding mechanism. Therefore, in the needle thread clamp device of this sewing machine, it is possible to start sewing from a state where the needle thread end is held,
It is possible to solve the conventional problems such as needle thread exposure at the beginning of sewing, non-formation of stitches due to the needle thread end coming out of the sewing needle, and formation of a spider web.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external configuration of a needle thread clamp device of a sewing machine.

FIG. 2 is a vertical cross-sectional view showing the configuration of a second thread tension member.

FIG. 3 is a front view of a needle thread holding mechanism.

FIG. 4 is an enlarged cross-sectional view showing the inside of the clamp portion of FIG.

FIG. 5 is a block diagram showing a configuration of a control system.

FIG. 6 is a perspective view showing a state where the tip of the wiper has moved to a position parallel to the sewing needle.

FIG. 7 is a perspective view showing a state in which the tip of the wiper catches the upper thread and moves up.

FIG. 8 is a perspective view showing a state where the tip of the wiper has moved to a position facing the suction port.

FIG. 9 is a flowchart showing the order of operations executed by the control means.

[Explanation of symbols]

10 Needle thread clamp device for sewing machine 11 First thread tension 12 Second thread tension 13 Holding mechanism 14 Electronic control device (control means) 15 wiper 15a Wiper tip 16 Threading mechanism 17 Upper thread 17a Upper thread end 18 sewing needles 27 spool (thread supply source) 37a Suction port 38 Elastic body 38a locking part 38b protrusion

Continued front page    F term (reference) 3B150 AA01 CB03 CD01 CD04 CD07                       CD10 CE06 CE17 CE27 FC02                       FC04 FD08 FH02 FH03 FH14                       FH17 GE03 GE13 JA02 JA11                       JA13 LA02 LB01 LB02 NA46                       NA47 NA48 NA49 NB14 NB15                       NB16 NB17 NC02 NC11 NC18                       QA06 QA07

Claims (4)

[Claims] 1. A first thread tension member, which is arranged on a thread path from a thread supply source to a sewing needle, and applies a weak tension to the upper thread, and a first thread tensioner, which is arranged on the thread path and applies a desired tension to the upper thread. A needle thread clamp device for a sewing machine, comprising a second thread tension member and a holding mechanism for holding an upper thread end derived from a sewing needle after thread cutting, wherein after the upper thread end is held by the holding mechanism, sewing is started. A needle thread clamp device for a sewing machine, comprising: a control unit that controls the second thread tension to release the tension applied to the needle thread substantially at a substantially same time. 2. A first thread tension member, which is arranged on a thread path from a thread supply source to a sewing needle, and applies a weak tension to the upper thread, and a first thread tensioner, which is arranged on the thread path and applies a desired tension to the upper thread. A second thread tensioner, a thread dragging mechanism that is arranged on the thread path and that performs reciprocating motion to pull up or move down the upper thread, and an upper thread end derived from a sewing needle after thread cutting are held. A needle thread clamp device for a sewing machine, which comprises a holding mechanism, and a needle thread clamp device for controlling the sewing machine to control the thread drag operation by the thread drag mechanism at substantially the same time as the start of sewing. apparatus. 3. A first thread tension member, which is arranged on a thread path extending from a thread supply source to a sewing needle, and applies a weak tension to the upper thread, and a first thread tensioner, which is arranged on the thread path and applies a desired tension to the upper thread. A second thread tensioner, a wiper having a tip portion capable of intersecting the needle bar vertical movement locus, and capable of capturing an upper thread end derived from a sewing needle after thread cutting by the tip portion; and a wiper of the wiper when the wiper is operated. A suction port is formed at a position facing the tip, and the needle thread end captured by the wiper is sucked,
In a needle thread clamp device of a sewing machine having a holding mechanism for holding, an outer peripheral portion of the suction port of the holding mechanism is inward of a movement locus of a tip portion of the wiper and in a substantially opening direction of the suction port. A needle thread clamp device for a sewing machine, comprising an elastic body provided with a protruding locking portion. 4. The needle thread clamp device according to claim 3, wherein at least a part of the engaging portion of the elastic body is formed with a downwardly projecting portion.