JP2002224483A - Thread cutter of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread cutter of a sewing machine that provides required sharpness of a thread cutting even if engagement pressure of a blade portion is low. SOLUTION: In the thread cutter of the sewing machine having thread catching members (11 and 46) capable of catching thread by movement, thread cutting knives (12 and 45) each having a blade portion and capable of cutting thread in cooperation with the thread catching members, a thread cutting solenoid (16) capable of connecting the thread catching members to the rotating hook shaft of the sewing machine, and reciprocating the thread catching members on the basis of a thread cutting signal, vibration generation means (24, 47 and 55) supporting the thread cutter and capable of adding minute vibration, and a control means (30) driving the vibration generation means on the basis of operations (thread cutting signal, backpedaling, sewing machine switch, or the like) are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread cutting device for a sewing machine, and more particularly to a device for applying a minute vibration to a thread cutting device to cut a thread.

[0002]

2. Description of the Related Art A conventional thread trimmer 1 of a vertical hook sewing machine shown in FIG. 11 includes a vertical hook 3 interlocked with a vertical movement of a needle 2 and a thread separating knife (a thread catching member) rotatable along the outer peripheral direction of the hook. ) 4
And a thread trimming knife 5 fixed to the sewing machine frame.

[0003] Based on a thread trimming signal by depressing the rear of the pedal,
A thread cutting solenoid (not shown) attached to the thread cutting device 1 is driven, and the thread separating knife 4 and the sewing machine lower shaft 13 are connected. Then, after the moving knife 4 reciprocates and interlocks with the lower shaft 13 to capture upper and lower threads on the cloth side, the moving knife 4 and the thread cutting knife 5 cooperate to cut the upper and lower threads.

[0004] A conventional thread trimmer 6 of a horizontal shuttle sewing machine shown in Fig. 12 is rotatably supported by a horizontal shuttle 7 which rotates in conjunction with the vertical movement of the needle 2 and a shuttle shaft stand (not shown). A moving knife 8 (thread catching member) for catching the upper and lower yarns on the cloth side by its reciprocating movement in a catching portion, and a fixed knife 9 (thread cutting knife) fixed to the shuttle shaft stand and having a blade portion. Have.

[0005] Based on a thread trimming signal by depressing the rear of the pedal,
Thread cutting solenoid attached to the thread cutting device (not shown)
Is driven, and the moving knife 8 and the lower shaft of the sewing machine are connected. Then, after the moving knife 8 reciprocates and interlocks with the lower shaft to capture upper and lower threads on the cloth side, the moving knife 8 cooperates with the fixed knife 9 to cut the upper and lower threads.

The sharpness of the yarn by the conventional thread cutting device (1, 6) is determined by the engagement pressure between the blades of the thread catching members (4, 8) and the blades of the thread cutting knives (5, 9). Was dependent. If the thread is thick or made of a material that is difficult to cut, the thread catching member (4, 8) or thread cutting knife (5, 9)
By changing the vertical position of the blade or using a scalpel having a large thickness, the engagement pressure of the blade portion was corrected so as to increase, and the thread was cut.

[0007]

However, in order to improve the sharpness of the thread, if the engaging pressure of the blade portion between the thread catching member and the thread cutting knife is increased, the number of times of thread cutting can be reduced.
There has been a problem that the blade portion is worn and the sharpness of the yarn is deteriorated.

Further, when the engaging pressure of the blade portion is high, the load on the driving device for moving the thread catching member or the thread cutting knife becomes large, and there is a problem that its life is shortened.
In particular, in a thread trimming device of a sewing machine in which a thread catching member is interlocked with the lower shaft of the sewing machine as a drive source, a rotational torque at the time of thread trimming increases, and a variation occurs in a stop position of the lower shaft of the sewing machine, that is, a stop position of the upper shaft. The problem arose.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made even if the engagement pressure of the blade portion is low.
An object of the present invention is to provide a sewing machine thread trimming device that can obtain a desired thread sharpness. It is another object of the present invention to provide a thread cutting device for a sewing machine that can obtain a predetermined thread sharpness without increasing the rotational torque of the lower shaft of the sewing machine during thread cutting.

[0010]

According to a first aspect of the present invention, there is provided a thread catching member (11, 46) capable of catching a thread by movement, a blade portion, and the thread catching member. A thread trimming knife (12, 4) capable of cutting a thread in cooperation with the catching member.
5) and a thread cutting solenoid (16) capable of connecting the thread catching member to the lower shaft of the sewing machine. The thread catching member is connected to the lower shaft based on a thread cutting signal, and the thread catching member is reciprocated. A thread generating device (24, 47, 55) capable of supporting the thread trimming knife and applying a minute vibration to the thread trimming device of the moving sewing machine, and performing operations (thread trimming signal, stepping behind a pedal, sewing machine switch, etc.) And a control means (30) for driving the vibration generating means based on the above.

[0011] The invention according to claim 2 provides a shuttle (40) that rotates in conjunction with the vertical movement of the needle bar, a shuttle shaft (42) that rotatably supports the shuttle, and a hook shaft (42). A yarn capturing member (46) rotatably supported and capable of capturing the yarn by movement;
A thread cutting knife (45) fixed to the shuttle shaft stand, having a blade portion, and capable of cutting a thread in cooperation with the thread catching member (45)
And a vibration generating means (24, 47, 55) that supports the shuttle shaft stand and can apply minute vibration to the shuttle shaft stand, and an operation (thread trimming signal, pedal). And a control means (30) for driving the vibration generating means based on a rear step, a sewing machine switch, etc.).

According to a third aspect of the present invention, in the thread trimming device for a sewing machine according to the first or second aspect, the vibration generating means includes:
It was configured to be an ultrasonic vibrator (24, 47).

According to a fourth aspect of the present invention, in the sewing machine thread trimming device according to the first or second aspect, the vibration generating means includes:
A structure including a support (52) to which a thread trimming knife is fixed, a support shaft (53) for rotatably supporting the support, and a motor (55) for imparting a swinging motion to the support. And

According to the present invention, a minute vibration is applied to the thread trimming knife or the shuttle shaft stand based on the thread trimming signal. For this reason, even if the engagement pressure of the blade portion is low, the desired sharpness of the yarn can be obtained. Further, since the engaging pressure of the blade portion is low, the rotational torque of the lower shaft of the sewing machine is reduced.

According to a fifth aspect of the present invention, in the sewing machine of the fourth aspect, a hole provided in the support base is provided.
An eccentric pin (54) fixed to the motor shaft is mounted.

According to the fifth aspect of the invention, the rotational movement of the motor is converted into minute vibration (small swing) of the thread trimming knife. For this reason, even if the engagement pressure of the blade portion is low, the desired sharpness of the yarn can be obtained.

According to a sixth aspect of the present invention, in the thread trimming device for a sewing machine according to the first or second aspect, the blade portion of the thread trimming knife is arranged so that its blade edge is directed vertically downward, and the vibration is generated. The means is configured to apply a vertical minute vibration.

According to a seventh aspect of the present invention, in the thread trimming device for a sewing machine according to the first or second aspect, the blade portion of the thread trimming knife is arranged such that its blade edge is directed vertically downward, and the vibration is generated. Means are 0 to the moving direction of the yarn catching member.
The configuration is such that micro vibration is applied within a range of 90 degrees.

According to the sixth and seventh aspects of the present invention, a desired thread sharpness can be obtained more reliably even when the engaging pressure of the blade portion is low.

According to an eighth aspect of the present invention, in the thread cutting device for a sewing machine according to the first or second aspect, the control means (30).
Is configured to control the vibration generating means according to sewing conditions (at least one control condition such as a thread tension, a thread material, and a thread thickness).

According to a ninth aspect of the present invention, in the sewing machine of the eighth aspect, the sewing condition is a thread tension.

According to the eighth and ninth aspects of the invention, since the vibration generating means is controlled according to the sewing conditions (amplitude, frequency, waveform, etc. of the vibration), the thread can be cut more reliably.

According to a tenth aspect of the present invention, in the thread trimming device for a sewing machine according to the first or second aspect, the thread trimming knife is
It has a configuration in which a blade portion is provided on the distal end side and the proximal end side is adjustably fixed to the vibration generating means.

According to the tenth aspect, by changing the fixing position of the thread trimming knife, the amplitude state of the thread trimming knife can be easily changed.

[0025]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIGS.

The first embodiment is a sewing machine provided with a vertical shuttle. The thread cutting device 10 has a thread separating knife 11 (thread catching member) for catching upper and lower threads to be cut by rotation, and is fixed to a sewing machine frame. And a thread cutting knife 12 that cuts upper and lower threads in cooperation with the thread separating knife 11.

Further, a shuttle (not shown) is attached to the lower end of the sewing machine lower shaft 13 for driving the thread cutter 10, and a thread cutter holder 14 is rotatably supported behind the shuttle. A thread cutting cam 15 is fixed behind -14. A thread separating knife 11 is fixed to the outer periphery of the thread cutting holder 14.

In the vicinity of the lower shaft 13, a thread cutting solenoid 16 is arranged along the axial direction thereof. An arm 17 is fixed to a plunger 16a which advances and retreats in the horizontal direction when the thread cutting solenoid 16 is turned on and off.
A roller 18 is attached to the tip end of the arm 17. When the plunger 16a moves forward, the roller 18
5 is engaged. When the lower shaft 13 rotates in a state where the roller 18 maintains the forward state, the roller 18 follows the outer peripheral locus of the thread cutting cam.

An L-shaped connecting member 19 is attached to the tip of the plunger 16a. The base 19a of the connecting member is urged in the illustrated f direction by a spring 20a. When the plunger 16a moves forward, the front end 19b of the connecting member engages with the lower end groove of the connecting plate 20. One end of the support shaft 21 rotatably supported by the thin frame is mounted and fixed to the upper end of the connecting plate 20. The other end of the support shaft 21 is connected to the arm of the thread cutting holder 14 via a link 22 and a link 23.

When the thread cutting solenoid 16 is driven, the plunger 16a advances in the direction e, the roller 18 on the tip side of the arm engages with the thread cutting cam 15, and the tip 19b of the connecting member is connected to the connecting plate. 20 groove.

When the lower shaft 13 rotates, the thread cutting cam 15,
The support shaft 21 is provided via the roller 18, the arm 17 and the connecting member 19.
Swings. With the swing of the support shaft 21, the link 2
The thread trimming holder 14 swings via 2 and 23. Then, the thread separating knife 11 reciprocates and approaches and separates from the thread cutting knife 12.

As shown in FIG. 2, the thread trimming knife 12 has an ultrasonic vibrator 24 and a horn 25 laminated on its lower part, and is fixed to the sewing machine frame by screws 26. The ultrasonic vibrator 24 converts high-frequency electric vibration generated by the oscillation drive circuit 27 into mechanical vibration. The horn 25 amplifies this mechanical vibration and transmits it to the thread trimming knife 12. The ultrasonic vibrator 24 vibrates in the vertical direction in the figure (vertical direction p), and vibrates the thread trimming knife in the vertical direction via the horn 25.

The thread trimming knife 12 has the blade 1
2a, and a long hole is formed in the proximal end 12b. For this reason, the thread trimming knife 12 is adjusted along the illustrated left-right direction g (horizontal direction) and fixed by the screw 26. By changing the fixing position of the thread trimming knife 12, the vibration (amplitude) state of the tip blade can be changed.
The thread cutting knife 12 has a distal end 12a having a blade portion that is gently bent (inclination of about 30 degrees with respect to a horizontal line), but the distal outer edge 12aa is substantially vertical.
The cutting edge 12aa formed on the thread cutting knife 12 meshes with the outer periphery of the thread separating unit 11 which performs a reciprocating rotary motion, and cuts the captured thread.

As shown in FIG. 3, the control means 30 of the thread cutting device 10 has a built-in CPU (central processing unit) 31. The CPU 31 has a ROM as storage means,
A RAM as a temporary storage means is connected.
In the ROM or the RAM, data for controlling the ultrasonic vibrator 24 or the like according to sewing conditions such as a thread tension sensor and a thread type, which will be described later, that is, data for changing the amplitude, waveform, and frequency of the vibration are stored. Is stored.

An operation panel 32 is connected to an input side of the control means 30 via an input interface 36. The operator can input a yarn count indicating the thickness of the yarn, a yarn type indicating the type of the yarn, and the like from the operation panel 32. The input side of the control means 30 is connected to a thread tension sensor 33, an upper shaft encoder 34 for detecting the rotation state of the upper shaft of the sewing machine, and a pedal sensor 35 for detecting the depression state of the sewing machine pedal. . Yarn tension sensor 3
Reference numeral 3 denotes a strain gauge arranged so as to partially cross the thread path of the sewing machine arm. When the sewing starts and tension occurs in the upper thread passed through the thread path, the strain gauge is pressed against the upper thread. This pressing force is detected and used as the yarn tension value.

On the output side of the control means, an ultrasonic transducer 24 is connected via an output interface 37 and an oscillation drive circuit 27.
Is connected. Further, a sewing machine motor 49 and a thread trimming solenoid 16 are connected via drive circuits 38 and 39, respectively.

The operation of the first embodiment will be described with reference to the flowchart of FIG.

First, when the power switch of the sewing machine is turned on, the process shown in FIG. 4 is started (step S1), and power is supplied to each part of the sewing machine. Next, in S2, when the operator steps on the sewing machine pedal, the pedal sensor-35 is pressed.
Detects this, the sewing machine motor 49 is driven and sewing is performed.

Next, in step S3, the pedal sensor 35 detects whether or not the pedal is depressed behind.
When this signal is detected and the upper shaft encoder 34 that detects the rotation of the main shaft detects the needle lower position, a sewing end thread trimming signal (thread trimming signal) is output.

Next, in step S4, at the same time as the output of the thread cutting signal,
The ultrasonic transducer 24 is output from the PU 30 and is driven via the output interface 37 and the oscillation drive circuit 26. The ultrasonic vibrator 24 vibrates, and this vibration is
Is amplified and transmitted to the thread trimming knife 12, and the thread trimming knife 12
Vibrates slightly.

It is preferable that the vibration state of the ultrasonic vibrator 24, that is, its frequency, amplitude, waveform, and the like be changed based on sewing conditions. The sewing conditions are at least one of a thread tension sensor 33 for detecting a thread tension, a thread count indicating a thread thickness, a thread type indicating a thread material, and the like, which are input by an operator through the operation panel 32. is there. For example, when a thick yarn is input, the CPU 31 increases the amplitude of the ultrasonic vibrator 24 as compared with the internal data, or increases the frequency of the ultrasonic vibrator 24 when the yarn tension is large. . Then, according to the sewing conditions (thread tension, thread material, thread thickness),
It is more preferable that the control conditions (frequency, amplitude, waveform, etc. of vibration) be automatically changed.

Next, in step S5, the thread trimming solenoid 16 is driven, and the thread trimming cam 15 fixed to the lower shaft 13 and the arm 17 are connected (engaged). And lower shaft 1
3, the thread separating knife 11 rotates and catches the upper and lower threads, and then cuts the thread in cooperation with the thread cutting knife 12. When cutting this thread, the thread trimming knife 12
Since the vertical vibration shown in the figure is given by
Even if the engagement pressure between the blade portion of the thread cutting knife 12 and the thread separating knife 11 is low, the thread can be easily cut.

Next, in step S6, it is determined from the needle bar upper stop position signal from the upper shaft encoder 34 that the lower shaft 13 has rotated a predetermined amount and the thread has been cut. When the needle bar stop position signal is detected, the sewing machine motor 49 is stopped, and the process proceeds to the next step.

Next, in step S7, the driving of the ultrasonic vibrator 24 is stopped, and the process ends.

According to the first embodiment, since the thread is cut by applying minute vibration to the thread cutting knife 12, the thread cutting knife 12
The desired sharpness of the yarn can be obtained even when the engagement pressure between the blade portion and the yarn separating knife 11 is low. Further, since the ultrasonic vibrator 24 is controlled according to the sewing conditions, the cutting can be performed more reliably, and the cutting marks are clear and the commercial value is improved.

Next, second to second modifications of the first embodiment will be described.
A fourth embodiment will be described with reference to FIGS.

In the thread cutting knife 12 of the first embodiment, the thread cutting knife 12 is slightly vibrated in a substantially vertical direction with respect to the thread separating knife 11 at the cutting position. This modification changes the vibration direction. For this reason, the same operations and control methods as those of the first embodiment are omitted, and the main parts thereof will be described below.

First, a second embodiment in which the thread trimming knife 12 is slightly vibrated in the horizontal direction based on FIG. 5 will be described.
The ultrasonic vibrator 24 is fixed to the sewing machine frame 28 of FIG. A horn 25 is fixed on the left side surface of the ultrasonic transducer 24 along the horizontal direction, and a holding groove is formed from the center of the horn 25 toward the right end. The proximal end 12a of the thread cutting knife 12 is supported in the holding groove along the horizontal direction, and is fixed at a predetermined position by a screw 26. When the oscillation drive circuit 27 is driven, the ultrasonic vibrator 2
4. Via the horn 25, the thread trimming knife 12 vibrates in the horizontal direction h to cut the thread. Due to the swing in the h direction, the thread is reliably cut even when the engagement pressure of the blade portion is low.

The third embodiment shown in FIG. 6 differs from the second embodiment in that the thread cutting knife 30 is rotated counterclockwise around the tip side blade portion 12b.
It has been rotated about degrees. The sewing machine frame supporting surface 28 that holds the ultrasonic vibrator is positioned 30 degrees counterclockwise.
Degrees.

In the third embodiment, as indicated by an arrow i, the thread trimming knife 12 vibrates slightly at an angle inclined by 30 degrees with respect to a horizontal line to perform thread trimming. By the swing in the i direction, the thread can be reliably cut even if the engagement pressure of the blade portion is low.

In the fourth embodiment shown in FIG. 7, the support shaft protruding from the sewing machine frame
9a is loosely fitted. A horn 25 and an ultrasonic vibrator 24 are stacked on the right side of the thread cutting knife holder 29 above the support shaft, and the right end of the ultrasonic vibrator 24 is fixed to a sewing machine frame 28. The base of the thread cutting knife 29 is fixed to the upper end surface of the thread cutting knife holder 29 by screws 26.

When the oscillation drive circuit 27 is driven, the ultrasonic vibrator 24 and the horn 25 slightly vibrate. Due to this minute vibration, the thread trimming knife holder 29 swings around the sewing machine frame support shaft. Then, the thread trimming knife 12 swings in the illustrated j direction. Due to the swing in the j direction, the thread is reliably cut even when the engagement pressure of the blade portion is low.

In the third embodiment, the thread cutter is slightly vibrated at an angle of about 30 degrees with respect to the moving direction (horizontal direction) of the thread cutter (thread catcher) 11 at the thread cutter position. In the fourth embodiment, the thread cutting knife is slightly vibrated at an angle of about 45 degrees with respect to the moving direction of the thread catching member. Alternatively, even if the thread cutting knife is slightly vibrated at an angle of about 0 to 90 degrees with respect to the moving direction (horizontal direction) of the thread catching member at the cutting position, the engaging pressure of the blade portion is low. However, the thread is reliably cut.

Next, a fifth embodiment will be described with reference to FIG.

In the fifth embodiment, the present invention is applied to a horizontal shuttle sewing machine. The operation, control method, and the like are the same as those in the first embodiment, and a description thereof will be omitted, and the configuration of main parts will be described.

The shuttle 40 is arranged below the needle plate, and is fixed above the shuttle shaft 41. The shuttle 40 and the shuttle shaft 41 are rotatably supported by a shuttle shaft base 42 having a U-shape in a side view. Hook shaft 41
Is housed in a shuttle shaft stand and connected to the sewing machine main shaft by gears 43 and 44 meshing with each other. And the pot 40
Rotates in conjunction with the vertical movement of the needle bar to form a seam.

A fixed knife 45 (thread cutting knife) is fixed on the upper part of the shuttle shaft stand 42. The tip blade of the fixed knife faces the outer periphery of the shuttle. In addition, moving knife (thread catching member)
46 is rotatably supported by the shuttle shaft stand 42. The moving knife 46 is connected to and disconnected from the main shaft of the sewing machine by a thread cutting solenoid (not shown) as in the first embodiment. Then, after the moving knife 46 captures the yarn by moving, the moving knife 46 cooperates with the fixed knife 45 to cut the yarn.

The shuttle shaft stand 42 is supported from above by a sewing machine frame via a horn 48 and an ultrasonic vibrator 47.

According to the fifth embodiment, when the thread cutting signal is generated, the ultrasonic vibrator 47 is driven and a minute vibration is generated in the shuttle shaft stand 42. The minute vibration of the shuttle shaft stand 42 is caused by the moving knife 4
6. It is transmitted to the fixed knife 45. When cutting the thread, the moving knife 46 and the fixed knife 45 vibrate minutely. For this reason, even if the engaging pressure between the moving knife and the fixed knife blade is low, the thread can be easily cut.

Next, a sixth embodiment will be described with reference to FIGS.

In the sixth embodiment, the thread trimming knife swings due to the rotation of the motor 55 to cause a minute vibration state in the thread trimming knife. The operation, control method, and the like of the sixth embodiment are similar to those of the motor 5 in place of the ultrasonic vibrator 24 of the first embodiment.
5, and the detailed description thereof is omitted. Hereinafter, the configuration of the main part will be described.

The thread trimming knife 50 shown in FIG. 9 is bent in a step shape on the side, and a blade portion 50a is formed on the tip end side. The main body 50b of the thread trimming knife is fixed to the upper surface of a knife holder (support table) 52 by a set screw 51. The female holder 52 is box-shaped, and has a support hole 52a formed in the lower part thereof. The support shaft 53 held by the sewing machine frame is mounted on the support hole 52a. The support shaft 53 rotatably supports the female holder 52. The female holder (support table) 52 has an arc-shaped protrusion at the center of the side surface, and a hole 52b is formed in the protrusion.

The center of the eccentric pin 54 is eccentric from the center of the eccentric pin 54 in the axial direction (lateral direction). One shaft of the eccentric pin 54 is connected to the hole 52 of the female holder (support base).
b. The other shaft 54a of the eccentric pin 54
Is fixed to the output shaft of the motor 55.

When the motor 55 (vibration generating means) rotates, the knife holder 52 swings the support shaft 52 in the illustrated L direction about the swing fulcrum. As a result, the thread cutting knife 50 swings in the illustrated m direction. Move. When the number of rotations of the motor is increased, a desired minute vibration of the thread cutting knife 50 occurs as in the first embodiment. Therefore, even if the engagement pressure between the thread cutting knife 50 and the thread separating knife is low, the thread can be easily cut. Further, by changing the number of rotations of the motor, the state of the minute vibration can be easily changed, and the optimum thread cutting is performed.

The present invention is not limited to the above embodiment, but can be variously modified.

For example, in the horizontal shuttle sewing machine according to the fifth embodiment, the shuttle shaft table is vibrated.
As in the first embodiment, it is easily conceivable that only the fixed knife is slightly vibrated.

In the above embodiment, the thread trimming knife is vibrated. However, it is easily conceivable to vibrate the thread separating knife.

In the above embodiment, the thread cutting knife is fixed, but it can be easily used as a movable thread knife.

In the above-described embodiment, the vibration generating means such as the ultrasonic vibrator or the motor is driven based on the thread cutting signal. It is also conceivable to drive the vibration generating means. By these operations, the vibration generating means is driven.

Further, in the above-described embodiment, the ultrasonic vibrator is used, but a piezoelectric element or the like may be used instead.

[0071]

As described above, according to the first to fourth aspects of the present invention, a minute vibration is applied to the thread trimming knife or the shuttle shaft stand based on the thread trimming signal. For this reason, even if the engagement pressure of the blade portion is low, the desired sharpness of the yarn can be obtained. Further, since the engaging pressure of the blade portion is low, the rotational torque of the lower shaft of the sewing machine is reduced.

According to the fifth aspect of the present invention, the rotational motion of the motor is converted into minute vibration (small swing) of the thread trimming knife. For this reason, even if the engagement pressure of the blade portion is low,
A desired thread sharpness is obtained.

According to the sixth and seventh aspects of the present invention, a desired thread sharpness can be obtained more reliably even when the engaging pressure of the blade portion is low.

According to the eighth and ninth aspects of the present invention, since the vibration generating means is controlled according to the sewing conditions, the thread can be more reliably cut.

According to the tenth aspect of the present invention, the amplitude state of the thread trimming knife can be easily changed by changing the fixing position of the thread trimming knife.

[Brief description of the drawings]

FIG. 1 is a perspective view of a thread cutting device of a sewing machine according to a first embodiment.

FIG. 2 is a front view of a main part of the first embodiment.

FIG. 3 is a block diagram of the first embodiment.

FIG. 4 is a flowchart of the first embodiment.

FIG. 5 is a front view of a main part of the second embodiment.

FIG. 6 is a front view of a main part of a third embodiment.

FIG. 7 is a front view of a main part of a fourth embodiment.

FIG. 8 is a front view of a main part of a fifth embodiment.

FIG. 9 is a perspective view of a sixth embodiment.

FIG. 10 is a front view of an essential part of a sixth embodiment.

FIG. 11 is a perspective view of a main part of a conventional thread trimmer of a vertical hook sewing machine.

FIG. 12 is a front view of a main part of a thread trimmer of a conventional horizontal shuttle sewing machine.

[Explanation of symbols]

 11. Thread separating knife (thread catching member) 46. Dynamic knife (thread catching member) 12. Thread trimming knife 45. Fixed knife (thread trimming knife) 16. Thread trimming solenoid 24. Ultrasonic vibrator (Vibration generating means) 47 Ultrasonic vibrator (Vibration generating means) 55 Motor (Vibration generating means) 30 Control means 40 Hook 42 Shaft stand 52 Female holder (Support base) 53-Support shaft 55-Motor 54-Eccentric pin

Claims (10)

[Claims] 1. A thread catching member capable of catching a thread by movement, a thread cutting knife having a blade portion and capable of cutting a thread in cooperation with the thread catching member, and a lower shaft of a sewing machine comprising the thread catching member. A thread cutting solenoid that can be connected to the thread cutting device, wherein the thread catching member is connected to a lower shaft based on a thread cutting signal, and the thread catching member reciprocates. And a control means for driving the vibration generating means based on an operation, and a thread trimming device for a sewing machine. 2. A shuttle that rotates in conjunction with the vertical movement of a needle bar, a shuttle shaft that supports the shuttle rotatably, and is rotatably supported by the shuttle axle and captures the yarn by movement. A thread trimming device for a sewing machine, comprising: a possible thread catching member; and a thread trimming knife fixed to the shuttle shaft stand, having a blade portion, and capable of cutting a thread in cooperation with the thread catching member. The sewing machine according to claim 1, further comprising: a vibration generating unit that supports the shuttle shaft stand, and that can apply minute vibration to the shuttle shaft stand; and a control unit that drives the vibration generation unit based on an operation. Thread cutting device. 3. The thread trimming device for a sewing machine according to claim 1, wherein said vibration generating means is an ultrasonic vibrator. 4. A thread trimming device for a sewing machine according to claim 1, wherein said vibration generating means comprises: a support base on which a thread trimming knife is fixed; a support shaft rotatably supporting said support base; And a motor for imparting a swinging motion to the support base. 5. The thread trimming device for a sewing machine according to claim 4, wherein an eccentric pin fixed to a motor shaft is mounted in a hole provided in said support base. 6. The thread trimming device for a sewing machine according to claim 1, wherein said blade portion of said thread trimming knife is disposed with its cutting edge directed vertically downward, and said vibration generating means is provided in a vertical direction. A thread trimming device for a sewing machine, which applies a minute vibration. 7. A thread trimming device for a sewing machine according to claim 1, wherein said blade portion of said thread trimming knife has a blade edge arranged vertically downward, and said vibration generating means includes said thread catcher. A thread trimming device for a sewing machine, wherein minute vibration is applied within a range of 0 to 90 degrees with respect to a moving direction of a member. 8. A thread trimming device for a sewing machine according to claim 1, wherein said control means controls said vibration generating means in accordance with sewing conditions. 9. The thread trimming device for a sewing machine according to claim 8, wherein said sewing condition is a thread tension. 10. The thread trimming device for a sewing machine according to claim 1, wherein said thread trimming knife has a blade portion on a distal end side, and a base end side is adjustably fixed to vibration generating means. Characteristic sewing machine thread trimming device.