JPH1033865A - Sewing machine - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a thread feeding device of a sewing machine that can uniformly and forcibly feed a thread required for forming a stitch by a mechanical configuration. . SOLUTION: This is a thread feeding device of a sewing machine which is incorporated in a sewing machine and feeds a thread. Then, a thread feeding mechanism 12, 1 that rotates to forcibly feed a thread necessary for stitch formation.
3, a transmission mechanism 16 to 19 for transmitting a motion required for thread feeding from a drive shaft 15 for driving the sewing machine to the thread feeding mechanisms 12 and 13, and a variable amount of momentum to be transmitted to the thread feeding mechanisms 12 and 13. Transmission variable mechanisms 24, 30
And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread feeding device for a sewing machine, which is incorporated in a sewing machine and feeds a thread.

[0002]

2. Description of the Related Art In sewing of a sewing machine, the amount of thread required for forming a stitch differs depending on the length of the stitch, the type of thread, the type of cloth, the thickness of cloth, and the like. Conventionally, in order to cope with this change in the amount of yarn, for example, a thread tension plate or the like is used to change the frictional resistance applied to the yarn, thereby adjusting the amount of yarn to be fed. In addition, as a method of adjusting the amount of yarn to be fed, a method of feeding a yarn with a pulse motor, a method of using a constant rotation motor and a solenoid, and the like, a predetermined amount of yarn can be fed at a predetermined timing by electric control. There are also things. In the system using the constant rotation motor and the solenoid, a constant rotation motor always applies tension to the yarn, and the solenoid grips and releases the yarn, thereby feeding a predetermined yarn.

[0003]

However, in the conventional adjustment of the amount of the thread to be paid out using the thread tension plate, the thread consumed for forming the stitch is simply pulled out against the frictional resistance. The amount of yarn drawn out varies.
There is a problem that the variation affects the formation of uniform seams. In addition, the conventional electric control described above has a problem that the sewing speed must be reduced due to the responsiveness of the motor and the solenoid when the amount of thread to be unwound is increased, and the amount of thread that can be unwound when the sewing speed is increased is reduced. There was a problem that would.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a mechanical structure in which a thread required for forming a stitch can be uniformly and forcibly fed out. It is intended to provide a device.

[0005]

Means for Solving the Problems In order to solve the above problems, an invention according to claim 1 is a thread feeding device for a sewing machine which is incorporated in a sewing machine and feeds a thread, wherein a thread necessary for forming a stitch is formed. A thread feeding mechanism that rotates and forcibly feeds the thread, and a transmission mechanism that transmits a motion required for feeding the thread from a drive shaft that drives the sewing machine to the thread feeding mechanism, and according to a rotation speed of the drive shaft, A fixed amount of yarn was forcibly supplied. According to the first aspect of the present invention, the movement of the drive shaft of the sewing machine is transmitted to the thread feeding mechanism via the transmission mechanism, whereby the thread feeding mechanism rotates to form a thread necessary for forming a stitch. The thread is forcibly fed. Therefore, the thread required for forming the stitch is unwound without variation, and a uniform stitch can be formed. Further, since the thread feeding mechanism is linked with the drive shaft of the sewing machine by the transmission mechanism and forcibly supplies a constant amount of thread according to the rotation speed of the drive shaft, for example, when the thread feeding amount is large, Even if the driving speed of the yarn is increased, the operation of the yarn unwinding mechanism becomes high while the amount of the unreeled yarn remains large. That is, no matter what the amount of thread to be paid out, a certain amount of thread necessary for stitch formation can be paid out in accordance with various driving speeds of the sewing machine.

Specifically, the thread feeding device of the sewing machine is applicable to feeding of a needle thread or feeding of a looper thread. The drive shaft for driving the sewing machine is a main shaft (also referred to as an upper shaft), a lower shaft, or various types of rotating shafts that rotate in conjunction with the main shaft. In addition, the above-described yarn feeding mechanism that forcibly feeds the yarn is achieved, for example, by setting two rollers in a rotatable state, pressing their outer peripheral portions to each other, and sandwiching the yarn between the pressing portions.
In addition, the above-described transmission mechanism is achieved by appropriately combining a gear, a belt, an eccentric mechanism, a cam, a slider, a link, and the like.

According to a second aspect of the present invention, in the thread feeding device for a sewing machine according to the first aspect of the present invention, the drive mechanism rotates the drive shaft by rotating the drive shaft so as to perform a thread feeding operation in response to a vertical movement of a sewing needle. And an irregular transmission mechanism capable of changing the phase of the movement of the yarn feeding mechanism while transmitting different movements according to the phase of the yarn feeding mechanism. According to the thread feeding device of the sewing machine according to the second aspect, the motion transmitted to the thread feeding mechanism by the irregular transmission mechanism is appropriately changed,
The operation of the thread payout mechanism corresponds to each phase of the elevating operation of the sewing machine needle. For example, the thread feeding operation is an operation of feeding a thread amount corresponding to each phase of the lifting / lowering operation of the sewing needle, or the feeding operation is performed at a timing suitable for the lifting / lowering operation of the sewing needle. As a result, the thread can be unwound without any excess or shortage in accordance with the elevating operation of the sewing machine needle, and a beautifully finished sewing can be performed. Also, since the phase of the movement of the line feeding mechanism can be changed by the irregular transmission mechanism,
The timing of the yarn feeding operation can be appropriately adjusted.

Specifically, the irregular transmission mechanism is, for example, an eccentric mechanism, a cam, a one-way clutch, or the like. In order to change the phase of the movement of the yarn feeding mechanism, for example, the fixed positions of these irregular transmission mechanisms may be changed to shift the phase of the movement transmission.

According to a third aspect of the present invention, in the thread feeding device for a sewing machine according to the first or second aspect, the transmission mechanism includes:
A variable transmission mechanism is provided for varying the amount of movement transmitted to the yarn feeding mechanism. According to the third aspect of the present invention, there is provided a transmission amount variable mechanism for varying a momentum to be transmitted to the yarn unwinding mechanism. By operating the transmission amount variable mechanism, the yarn is unwound. The amount can be adjusted. Therefore, the length of the seam,
Even when the type of the yarn, the type of the cloth, the thickness of the cloth, and the like are changed, it is possible to change the payout amount of the yarn in accordance with the change.

Specifically, the above-described variable transmission amount mechanism includes, for example, a mechanism using a transmission gear, and a mechanism in which the arrangement of guide grooves of a slide is changed to change the movement amount of the slide. Various known techniques are applicable.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. <First Embodiment> FIG. 1 is a schematic diagram showing a state in which a thread pay-out device 10 according to an embodiment of the present invention is incorporated in a sewing machine 1. As shown in FIG. 1, a thread pay-out device 10 of this embodiment is incorporated in a sewing machine 1 and forcibly feeds a thread of a bobbin 4 toward a sewing needle 7 in conjunction with an upper shaft 3. ing. The unwound thread is sent to the sewing machine needle 7 through the thread guides 5,... And the balance 5a.

FIG. 2 is an enlarged view showing the yarn feeding device 10 of FIG. 1, and FIG. 3 is an enlarged view of the yarn feeding device 10 viewed from the direction of arrow A in FIG. This yarn feeding device 1
Numeral 0 denotes a pitch change slider provided with a thread feeding roller 12, a driven roller 13, an output shaft 15, an eccentric mechanism (eccentric cam) 16, a slider 17, a connecting link 18, a swing arm 19, a one-way clutch 20, and a guide groove 25. 24, a slider fixing plate 30 and the like. First, an outline of the configuration will be described. Yarn feeding roller 12 and driven roller 1
Numeral 3 constitutes a yarn feeding mechanism. This thread feeding mechanism forcibly feeds a thread from the bobbin 4 to the sewing needle 7 side. The output shaft 15 is connected to the upper shaft 3 for driving the sewing machine 1, and guides the power for driving the thread feeding device 10 from the upper shaft 3. Eccentric mechanism (eccentric cam) 1
6, guide groove 25, slider 17, connecting link 18, swing arm 1
9 and the one-way clutch 20 constitute a transmission mechanism. This transmission mechanism transmits the movement of the output shaft 15 to the yarn feeding roller 12. In this transmission mechanism, the eccentric mechanism 16 and the one-way clutch 20
Transmits different movements in accordance with the phase of rotation of the output shaft 15, so that the yarn feeding-out operation by the yarn feeding-out roller 12 is performed with the operation and timing corresponding to the lifting / lowering operation of the sewing machine needle. It has become. The pitch changing slider 24 and the slider fixing plate 30 are connected to the output shaft 15 from the yarn feeding roller 12.
A variable transmission amount mechanism that varies the amount of movement transmitted to the motor.

Next, the configuration will be described in detail. The yarn feeding roller 12 is fixed so as to be rotatable around a rotating shaft 23 via a one-way clutch 20 described later. The driven roller 13 is rotatable about a rotation shaft 13b, and its outer peripheral portion 13a is
Is fixed to the fixing plate 37 in a state in which a load is applied to the outer peripheral portion 12a of the member and pressed against the outer peripheral portion 12a. Then, the yarn is forcibly fed by the rotation of the yarn feeding roller 12 and the rotation of the driven roller 13 following the rotation of the yarn feeding roller 12 with the yarn sandwiched by the press contact portion. Outer peripheral portions 12a of these rollers,
13a is formed of a member having a slight elasticity and friction, such as a synthetic resin, so that the yarn can be pulled out from the bobbin 4 without slipping while sandwiching the yarn. The output shaft 15 is connected to the upper shaft 3 of the sewing machine via bevel gears 40 and 41 (see also FIG. 3). The bevel gears 40, 4
By changing the gear ratio of 1, the rotation ratio of the upper shaft 3 and the rotation ratio of the output shaft 15 can be made different, whereby a plurality of yarn feeding operations can be performed during one rotation of the upper shaft 3. For example, the rotation ratio of the upper shaft 3 can be increased for a single yarn feeding operation.

The eccentric mechanism 16 converts the rotational movement of the output shaft 15 into a reciprocating movement of the swing rod 16a. The eccentric mechanism 16 is fixed to the output shaft 15 by tightening a fixing screw 16b.
By adjusting the rotational position of the swing rod 16a relative to the rotational position of the output shaft 15, the phase position of the reciprocating motion of the swing rod 16a can be adjusted. The slide 17 is slidably engaged along the guide groove 25, and the swing rod 16 a of the eccentric mechanism 16 and one end of the connection link 18 are rotatable about the connection pin 21 on the slide 17. Are linked. The other end of the connection link 18 and one end of the swing arm 19 are rotatably connected around a connection pin 22, and the other end of the swing arm 19 is fixed to a rotation shaft 23. Rotary axis 2
Numeral 3 is connected to the line feeding roller 12 via a one-way clutch 20. The one-way clutch 20
Rotationally fixed to the bearings 35, 35, the rotation is transmitted to the yarn feeding roller 12 in one direction (counterclockwise rotation in FIG. 2) of the rotation of the center shaft 23, but is rotated in the other direction. (Clock rotation in FIG. 2) does not transmit the motion.

According to the transmission mechanism including the eccentric mechanism (eccentric cam) 16, the guide groove 25, the slider 17, the connecting link 18, the swing arm 19, the one-way clutch 20, and the like, first, the output shaft 15 Rotates, the eccentric mechanism 1
6 converts the rotational movement into a reciprocating movement of the swing rod 16a, and the slide 17 connected to the swing rod 16a
A reciprocating motion is performed along 5. The reciprocating motion is transmitted to the swing arm 19 by the connection link 18, and the swing arm 19 performs a reciprocating rotation motion that reciprocates at a predetermined angle around the rotation shaft 23. Of the reciprocating rotation, only the rotation in one direction is transmitted to the yarn feeding roller 12 by the one-way clutch 20, and a predetermined time interval (time interval for a half rotation of the output shaft 15) at the yarn feeding roller 12.
An intermittent rotational movement of rotating in only one direction while opening is performed. The pitch change slider 24 is provided with a guide groove 25 and a slider operation section 27. The pitch change slider 24 is fixed to a bearing 36 so as to be rotatable about a rotation shaft 26, and can be rotated about the rotation shaft 26 by operating a slider operation unit 27. I have. An engagement groove 24a is provided at one end of the pitch change slider 24.

In other words, by changing the position of the pitch changing slider 24, the position and angle of the guide groove 25 which determines the path of the slider 17 are changed, whereby the eccentric mechanism 16 moves to the slider 17 from the eccentric mechanism 16. The pitch of the transmitted reciprocating motion is changed. Slider fixing plate 30
Is for fastening the slider operation section 27 to fix the pitch changing slider 24 so as not to move.
In the slider fixing plate 30, positioning holes 30a, 30b.
The positioning hole 30 is provided by using, for example, a pin.
a, 30b... and the engagement groove 24 of the pitch changing slider 24
a, the pitch change slider 24
Can be positioned. This makes it easy to change the pitch change amount to an intermittent predetermined value. The yarn feeding device 10 of this embodiment is configured as described above, and the yarn feeding mechanism, the transmission mechanism, and the transmission amount changing mechanism operate to feed the yarn, adjust the feeding amount, and operate as follows. The adjustment of the delivery timing is performed. That is, as the yarn feeding operation, first, when the upper shaft 3 rotates and the sewing machine is driven, as described above, the rotation of the upper shaft 3 is transmitted by the transmission mechanism, and the yarn feeding roller 12 intermittently rotates. Exercise is performed.

When the thread feeding roller 12 rotates, the driven roller 13 also rotates accordingly, and the thread sandwiched between the press-contact portions of the thread feeding roller 12 and the driven roller 13 is forcibly sent out to the sewing needle 7 side. That is, a fixed amount of thread is intermittently sent out to the sewing needle 7 with the intermittent rotation of the thread feeding roller 12. Since the intermittent yarn feeding operation is performed in the same cycle as the rotation of the output shaft 15, the yarn ratio is changed by changing the gear ratio of the bevel gears 40 and 41 connecting the output shaft 15 and the upper shaft 3. The number of thread feeding operations during one rotation of the upper shaft 3 of the sewing machine,
That is, it is possible to change the number of thread feeding operations that are performed while the sewing needle moves up and down once. For example, by setting the gear ratio of the bevel gears 40 and 41 to 1: 1 so that the threading operation is performed once while the sewing machine needle moves up and down once, or the gear ratio is set to 2: 1. Thus, the thread pay-out operation can be performed twice while the sewing machine needle moves up and down once. The timing of the yarn feeding operation is adjusted by operating the fixing screw 16b of the eccentric mechanism 16 to change the fixed position of the rotation angle between the eccentric mechanism 16 and the output shaft 15. For example, if the fixed position is advanced by 90 degrees, the timing of the yarn feeding operation is advanced by １ ／ rotation of the output shaft 15, and if the fixed position is advanced by 90 degrees, the output position is adjusted by 90 degrees. 1/4 of axis 15
The timing of the yarn feeding operation is delayed by the amount corresponding to the rotation.

Further, for example, when the amount of thread required for forming a stitch is changed due to a change in a sewing product or a sewing method, the slider operating section 27 is operated to operate the pitch changing slider 24. By moving the fixed position, it is possible to adjust the amount of the thread to be paid out. For example, the engagement groove 24a of the pitch change slider 24 is
Is fixed in accordance with the positioning 30a, the pitch of the reciprocating movement of the slider 17 is reduced, and the change in the pitch reduces the amount of movement transmitted to the connecting link 18 and the swing arm 19, thereby reducing the yarn feeding roller 12 , That is, the amount of thread to be paid out is reduced. Further, if the engagement groove 24a of the pitch changing slider 24 is fixed in accordance with the positioning 30d of the slider fixing plate 30, the pitch of the reciprocating motion of the slider 17 increases, and by changing the pitch,
The amount of movement transmitted to the connecting link 18 and the swing arm 19 is increased, and the amount of rotation of the yarn feeding roller 12, that is, the amount of feeding of the yarn is increased. As a result, the amount of thread that is required for forming the stitch can be adjusted. As described above, according to the thread pay-out device 10 of this embodiment, a constant amount of thread necessary for stitch formation is forcibly fed by the thread pay-out mechanism, so that uniform seam formation can be performed. You can do beautifully finished sewing. Further, the above-mentioned transmission mechanism allows the thread pay-out mechanism to be linked with the movement of the drive shaft of the sewing machine. The operation of the yarn feeding mechanism becomes faster while the feeding amount remains large. That is, no matter what the amount of thread to be paid out, the thread necessary for stitch formation can be paid out according to various driving speeds of the sewing machine.

Further, the thread can be intermittently fed by the eccentric mechanism 16 and the one-way clutch 20 and the like, and the thread feeding operation can be matched with the lifting / lowering operation of the sewing needle 7. It is possible to feed the yarn without excess or deficiency in accordance with the operation. Further, by changing the fixed position of the pitch change slider 24, it is possible to adjust the amount of thread to be paid out, and the length of the sewing stitch, the type of thread, the type of cloth, the thickness of cloth, and the like are changed. Even in such a case, it is possible to adjust the amount of the thread to be fed to those changes. The present invention is not limited to the yarn feeding device 10 according to the present embodiment.
As an object of the application, the present invention may be applied to paying out a sewing thread, or may be applied to paying out a looper thread. that time,
The thread pay-out device may be driven in conjunction with the lower shaft of the sewing machine. Further, the operation of the thread feeding device is not limited to the intermittent feeding operation.For example, by using a cam, the momentum transmitted according to the phase of rotation of the drive shaft of the sewing machine is appropriately changed. Thus, it is also possible to variously change the thread feeding operation in accordance with the operation of the sewing needle. In addition, specific configurations, detailed structures, and the like of the thread pay-out mechanism, the transmission mechanism, and the transmission amount variable mechanism can be appropriately changed without departing from the spirit of the present invention.

<Second Embodiment> FIG. 4 is an enlarged view of a yarn feeding device 50 according to a second embodiment of the present invention. In the yarn feeding device 50 according to the second embodiment, the same components as those of the yarn feeding device 10 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted. This yarn feeding device 50 is a yarn feeding device 1 according to the first embodiment.
0 in the following points. That is, the yarn feeding device 5
0 and a method of connecting the sewing machine upper shaft 3 to the sewing machine upper shaft 3, and the thread feeding device 50 at the attachment position to the sewing machine upper shaft. Regarding the connection method, in the first embodiment, the eccentric mechanism 16 is connected via the bevel gears 40 and 41 and the output shaft 15.
And the sewing machine upper shaft 3 are connected. On the other hand, in this embodiment, the eccentric mechanism 16 and the sewing machine upper shaft 3 are directly connected. With respect to the attachment position, the attachment position of the yarn feeding device 10 of the first embodiment is
The yarn feeding device 50 of this embodiment is attached at a position rotated by 90 degrees. That is, the thread pay-out device 50 of this embodiment includes the eccentric mechanism 16 and the sewing machine upper shaft 3.
Are easily connected directly to each other, and the connection method and the connection mechanism (for example, the connection mechanism between the eccentric mechanism 16 and the upper shaft 3 of the sewing machine) are simpler than the yarn feeding device 10 according to the first embodiment. Has been Adjustment of the timing of the yarn feeding operation in the yarn feeding device 50 of the second embodiment is performed by running the fixing screw 16b of the eccentric mechanism 16 similarly to the first embodiment. . In addition, when changing the amount of thread required for stitch formation, the slider operation unit 27 is operated.

<Third Embodiment> FIG. 5 is an enlarged view of a yarn feeding device 60 according to a third embodiment of the present invention. The yarn feeder 60 according to the third embodiment has substantially the same configuration as the yarn feeder 10 according to the first embodiment, except that an actuator is connected to a variable transmission amount mechanism, Is that the amount of the thread to be paid out can be changed by a simple control. Therefore, the same components as those of the yarn feeding device 10 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted, and different configurations will be described. The yarn feeding device 60 includes a yarn feeding mechanism including a yarn feeding roller 12 and a driven roller 13,
A transmission mechanism including an eccentric mechanism (eccentric cam) 16, a slider 17, not shown, a connecting link 18, a swing arm 19, a one-way clutch 20, not shown, and a guide groove 25, not shown.
Transmission variable mechanism consisting of a pitch changing slider 24 provided with a slider and a slider fixing plate 30, and a bevel gear 4
3, 44, pulse motor 4 as actuator
6 and so on. The eccentric mechanism 16 is directly connected to the upper shaft 3 of the sewing machine.

The bevel gear 43 is fixed to the rotating shaft 26 of the pitch changing slider 24. The bevel gear 44 is fixed to a rotation shaft 46a of the pulse motor 46. The bevel gears 43 and 44 are connected to each other, and the pitch changing slider 24 is rotated by the rotation of the pulse motor 46 to rotate the rotation shaft 26.
It is designed to rotate around. Pulse motor 4
Reference numeral 6 is connected to, for example, a control circuit that controls the operation of the sewing machine 1, and the rotational drive of the pulse motor 46 is controlled by the control circuit. As mentioned above,
According to the yarn feeding device 60 of the third embodiment,
The pitch change slider 24 can be rotated by driving the pulse motor 46 to adjust the amount of thread to be paid out. For example, during sewing, the cloth thickness or the stitch length is changed, and the stitch formation is performed. Even if the required thread length changes, it is possible to respond to these changes by electrical control, and also to increase or decrease the thread advance amount at the start of sewing, or to increase or decrease the thread advance amount just before thread trimming. It is possible to measure the stability of sewing and the stability of tightening of the thread cutting part. In addition, the type of the actuator connected to the transmission variable mechanism and the connection method are not limited to those described above, and can be appropriately changed.

[0023]

According to the first aspect of the present invention, the movement of the drive shaft of the sewing machine is transmitted to the thread feeding mechanism by the transmission mechanism, whereby the thread feeding mechanism rotates and is necessary for stitch formation. Forcibly pay out the yarn. Therefore, the thread required for forming the stitch is unwound without variation, and a uniform stitch can be formed. Also,
By the above-mentioned transmission mechanism, the thread pay-out mechanism is interlocked with the movement of the drive shaft of the sewing machine.For example, even if the drive speed of the sewing machine is increased when the thread pay-out amount is large, the thread pay-out amount is The operation of the line payout mechanism becomes faster at a high speed. That is, no matter what the amount of thread to be paid out, the thread necessary for stitch formation can be paid out according to various driving speeds of the sewing machine.

According to the second aspect of the present invention, the transmission mechanism is different depending on the phase of rotation of the drive shaft of the sewing machine so that the operation of feeding the thread corresponds to the operation of lifting and lowering the sewing machine needle. Since the irregular transmission mechanism for transmitting the movement is provided, the movement transmitted to the thread pay-out mechanism by the irregular transmission mechanism is changed appropriately, and the thread pay-out mechanism corresponds to each phase of the elevating operation of the sewing machine needle. Then, the operation of feeding the thread amount according to the phase is performed, and the operation of feeding the thread is performed at a timing that matches the raising / lowering operation of the sewing needle. As a result, the thread can be paid out without excess or deficiency in accordance with the raising / lowering operation of the sewing needle, and a beautifully finished sewing can be performed. Also, usually, the above-mentioned irregular transmission mechanism can change the phase of the transmitted motion by changing the fixed position of the front and rear connecting portions, so that the timing of the yarn feeding operation can be adjusted by adjusting the fixed position. It can be adjusted appropriately.

According to the third aspect of the present invention, there is provided a variable transmission mechanism for varying the amount of momentum transmitted to the thread supply mechanism. Can be adjusted. Therefore, even when the length of the stitch, the type of thread, the type of cloth, the thickness of cloth, and the like are changed, the amount of thread to be paid out can be changed in accordance with the change.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in which a thread pay-out device according to a first embodiment of the present invention is incorporated in a sewing machine.

FIG. 2 is an enlarged view showing a part of the yarn feeding device of FIG. 1;

FIG. 3 is an enlarged view of the yarn feeding device as viewed from the direction of arrow A in FIG. 2;

FIG. 4 is an enlarged view showing a yarn feeding device according to a second embodiment of the present invention.

FIG. 5 is an enlarged view showing a yarn feeding device according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sewing machine 3 Upper shaft 4 Bobbin 7 Sewing needle 10, 50, 60 Thread feeding device 12 Thread feeding roller (constituting thread feeding mechanism) 13 Follower roller 15 Output shaft 16 Eccentric mechanism 17 Slider 18 Connecting link 19 Oscillating arm Reference Signs List 20 one-way clutch 24 pitch changing slider (constituting variable transmission amount mechanism) 30 slider fixing plate 46 pulse motor

Claims (3)

[Claims] 1. A thread feeding device for a sewing machine, which is incorporated in a sewing machine and feeds a thread, comprising: a thread feeding mechanism for rotating a thread necessary for forming a stitch and forcibly feeding the thread; and a drive shaft for driving the sewing machine. And a transmission mechanism for transmitting a movement required for feeding the thread to the thread feeding mechanism, wherein a constant amount of thread is forcibly supplied according to the rotation speed of the drive shaft. apparatus. 2. A transmission mechanism according to claim 1, wherein a different motion is transmitted to the transmission mechanism in accordance with a rotation phase of the drive shaft, and a motion of the thread feeding mechanism is performed. The thread feeding device for a sewing machine according to claim 1, further comprising an irregular transmission mechanism capable of changing a phase of the thread. 3. The thread feeding device of a sewing machine according to claim 1, wherein the transmission mechanism includes a transmission amount variable mechanism that varies a momentum transmitted to the thread feeding mechanism. .