JPH07255981A - Thread cutting device for cycle sewing machine - Google Patents

Abstract

(57) [Abstract] [Purpose] In a thread trimming device for a cycle sewing machine, a method that does not connect to a conventional presser foot lifting mechanism, has a simple configuration without using a thread trimming control cam, etc. To enable good thread trimming control over a long period of time. [Structure] During a sewing operation of a predetermined cycle, a drive unit 3 of an actuator 30 by a solenoid or a cylinder.
0a is caused to project so that the thread cutting cam arm 8 is separated from the cam surface of the thread cutting cam 6 provided on the main shaft 2 driven by the drive motor 4 such as a servomotor or an electromotor whose rotation state is electrically controlled. . Then, when the timing corresponding to the final needle of the sewing operation of the predetermined cycle is reached, the driving portion 30a of the actuator 30 is returned to bring the thread cutting cam arm 8 into contact with the cam surface of the thread cutting cam 6, Causes a predetermined thread cutting operation to be performed.

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 of a cycle sewing machine for sewing a predetermined shape.

[0002]

2. Description of the Related Art For example, a cycle sewing machine for sewing various shapes such as bar tacks is generally known.
In this cycle sewing machine, the thread cutting operation is performed at the timing corresponding to the last stitch after the completion of one cycle of the sewing operation. The thread cutting mechanism for cutting the thread cuts the upper and lower threads connected to the needle and the shuttle from the object to be sewn by the reciprocating movement of the moving blade.

For example, in the thread trimming device disclosed in Japanese Examined Patent Publication No. 62-622, the thread trimming timing is set by interlocking the blocking frame, and the thread trimming is performed on the cam surface of the thread trimming cam fixed to the main shaft. A predetermined operation is transmitted to the thread cutting mechanism by the cam arm being pressed against and swinging, so that the thread separating operation and the thread cutting operation are executed.

In such a conventional cycle sewing machine, as disclosed in Japanese Examined Patent Publication No. 61-19276, a general-purpose motor is usually adopted as a drive source for the spindle, and the sewing speed is increased or decreased accordingly. Device, a clutch mechanism for transmitting or shutting off the driving force (for rotating and stopping the sewing machine), the shutoff frame described above, and the like. Then, as described above, the thread trimming device is also configured so that the drive source for driving the thread trimming device is also a reducing device that utilizes the output from the motor and is interlocked with the blocking frame.

[0005]

However, in the conventional cycle sewing machine having such a thread cutting device interlocking with the breaking frame, the structure is complicated and the number of parts is large, and a large force is applied to the cam of the breaking frame. Is loaded and there is a problem with durability.

In order to solve this, it is conceivable to omit parts such as a speed increasing / decreasing device and a shutoff frame by using a servomotor or an electromotor whose rotation state can be electrically controlled to stop at a fixed position. However, at that time, there is a problem in how to control the thread cutting described above.

Therefore, the applicant of the present invention has proposed a thread trimming control device for a cycle sewing machine which has a simple structure and is capable of excellent thread trimming control over a long period of time.
Proposed in No. 93838.

As shown in FIG. 3, the main shaft 2 is rotationally driven by a drive motor 4 whose rotational state is electrically controlled, and a predetermined sewing operation is repeated every cycle. In a thread trimming control device of a cycle sewing machine equipped with a thread trimming mechanism that reciprocates a moving blade to perform thread trimming operation of a sewing thread, the thread trimming cam 6 fixed to the main shaft 2 is pressed against the cam surface thereof. Which is rocked and transmitted a predetermined thread cutting operation to the thread cutting mechanism.
And a thread trimming control cam 23 which makes one rotation during one cycle of the sewing operation in cooperation with the spindle 2, and the thread trimming control cam 23.
Of thread trimming control lever 20 which oscillates by pressing against the cam surface of
And a thread trimming control arm 18 that engages / separates with the swinging portion of the thread trimming control lever 20 to bring the thread trimming cam arm 8 into contact with / separate from the cam surface of the thread trimming cam 6. It is a feature.

According to this structure, specifically, when the presser foot lifting mechanism (not shown) raises and holds the cloth presser, the presser foot lifting link 33 descends to move the upper and lower rods 3.
4 descends and pushes the limiting plate 32 downward,
Engages on the roller 12 of the thread cutting cam arm 8 and the roller 10 of the thread cutting cam arm 8 separates from the thread cutting cam 6. Therefore, the thread trimmer does not operate. Also, when the presser foot lifting mechanism lowers the cloth presser, the upper and lower rods 34 rise and the limiting plate 32 tries to rotate clockwise by the tension spring 35. However, the roller 12 is urged by the tension spring 25 to cause the limiting plate 32 to rotate. Since it is engaged with the restriction plate 32, the restriction plate 32 does not rotate and maintains the state as it is.

When sewing is started, the thread trimming control cam 23 rotates through the rotary shaft 24 which is rotated once during one cycle of the sewing operation in cooperation with the main shaft 2, and the thread cutting operation is performed by the urging force of the tension spring 26. The roller 22 of the control lever 20 rides on the cam non-forming surface 23a of the thread trimming control cam 23, and the other end of the thread trimming control lever 20 pushes the thread trimming control arm 18 to rotate the shaft 17 and resist the tension spring 25. The thread trimming link 13 is rotated downward to push down the thread trimming connecting rod 11. As a result, the engagement between the limiting plate 32 and the roller 12 is released, and the limiting plate 32 is rotated upward by the urging force of the tension spring 35.

When the limiting plate 32 is separated from the roller 12, the thread-cutting connecting rod 11 whose upper end is rotatably connected to the roller 12 of the thread-cutting cam arm 8 can be raised, and the shaft 17 is rotated. Try to activate the thread trimming mechanism. However, as described above, while the roller 22 of the thread trimming control lever 20 is on the cam non-forming surface 23a of the thread trimming control cam 23, that is, during sewing, the thread trimming control lever 20 pushes the thread trimming control arm 18 to rotate the shaft. 17 rotation, tension spring 2
Since the thread cutting link 13 is rotated against 5 to push down the thread cutting connecting rod 11, the thread cutting control lever 20
The thread trimming cam arm 8 with its roller 10
Acts to move away from. Therefore, the thread trimming mechanism does not operate until the roller 22 of the thread trimming control lever 20 enters the cam forming surface 23b of the thread trimming control cam 23. Therefore, malfunction of the thread trimming mechanism during sewing can be prevented. .

As described above, the thread trimming control lever 20 is in pressure contact with the cam non-forming surface 23a of the thread trimming control cam 23 during the course of one cycle of the sewing operation, whereby the thread trimming cam 6 moves. The thread trimming control arm 18 is maintained at a position where the thread trimming cam arm 8 is separated from the cam surface.
Therefore, the thread cutting operation is not performed.

Next, at the timing corresponding to the last needle of the sewing operation of one cycle, the thread trimming control lever 20 moves onto the cam forming surface 23b of the thread trimming control cam 23, whereby the thread trimming cam 6 is released. The thread trimming control arm 18 moves to a position where the thread trimming cam arm 8 abuts on the cam surface, and the thread trimming cam arm 8 performs a predetermined swing motion based on the thread trimming cam 6 to perform the thread trimming operation. Be seen.

As described above, during one cycle of sewing operation, the thread trimming control lever 20 is pressed against the cam non-forming surface 23a of the thread trimming control cam 23 so that the thread trimming cam arm 6 moves from the cam surface of the thread trimming cam 6. 8 apart and 1
When the timing corresponding to the last needle of the cycle sewing operation is reached, the thread trimming control lever 20 is moved to the thread trimming control cam 2
3 is moved to the cam forming surface 23b, and the thread cutting cam arm 8 is brought into contact with the cam surface of the thread cutting cam 6, whereby a predetermined thread cutting operation is performed.

The thread cutting operation is performed by the thread cutting control lever 20.
The thread trimming control arm 18 which is in the locked state at the other end side of the thread swings rearward (left side in the figure), and the thread trimming cam arm 8 is pressed against the cam surface of the thread trimming cam 6 to The thread-cutting cam arm 8 performs a predetermined swinging motion based on the cam 6, and is transmitted to a thread-cutting mechanism (not shown) as a thread-cutting operation by the thread-cutting connecting rod 11 and the thread-cutting link 13. The thread cutting operation is performed.

However, in such a thread trimming control device for a cycle sewing machine, since the thread trimming mechanism is connected to the presser lifting mechanism, in order to control the thread trimming, the roller 12 of the thread trimming cam arm 8 and the limiting plate 32 are controlled. , Presser foot link 3
3, a large number of parts such as the upper and lower rods 34, the thread trimming control arm 18, the thread trimming control lever 20, the roller 22 and the tension spring 26, the thread trimming control cam 23, the rotary shaft 24, etc. are required, which is mechanically complicated. The cost was also extra.

It should be noted that, for example, using a solenoid or cylinder actuator,
Although there is one in which the tip end portion of the presser foot lifting link 33 is brought into contact with or separated from the tip end portion, the thread trimming mechanism is still connected to the presser foot lifting mechanism, and therefore, there is the same problem as described above. ing.

Therefore, an object of the present invention is a system which is not connected to a conventional presser-lifting mechanism and which has a simple structure without using a conventional thread cutting control cam or the like and is capable of satisfactorily cutting a thread for a long period of time. It is an object of the present invention to provide a thread cutting device of a cycle sewing machine capable of performing control.

[0019]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention rotatably drives a main shaft using a drive motor whose rotation state is electrically controlled, and a predetermined sewing operation is performed every predetermined cycle. In a thread trimming device of a cycle sewing machine having a thread trimming mechanism for reciprocally moving a moving blade to perform thread trimming operation of a sewing thread, a thread trimming cam fixed to the main shaft and the thread trimming mechanism. A thread cutting cam arm that is pressed into contact with the cam surface of the cam and swung to transmit a predetermined thread cutting operation to the thread cutting mechanism, and a cam of the thread cutting cam that contacts and separates from the thread cutting cam arm. And an actuator such as a solenoid or a cylinder for bringing the thread cutting cam arm into contact with or away from the surface.

[0020]

According to the present invention, the driving portion of the actuator is in contact with the thread cutting cam arm from the start of sewing in a predetermined cycle to the middle thereof, whereby the thread cutting cam arm and the thread cutting cam are not in contact with each other. The thread cutting operation is not performed. Then, when the timing corresponding to the final needle of the sewing operation of the predetermined cycle is reached, the drive portion of the actuator separates from the thread cutting cam arm, and the thread cutting cam arm is pressed against the outer peripheral surface of the thread cutting cam. As a result, the thread trimming cam arm performs a predetermined swing motion based on the cam surface of the thread trimming cam, and is transmitted to the thread trimming mechanism via the thread trimming connecting rod, the thread trimming link, etc., and the predetermined thread trimming motion is performed. Done.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thread cutting device for a cycle sewing machine according to the present invention will be described below with reference to FIGS.

First, FIG. 1 shows the internal structure of a cycle sewing machine as an example to which the present invention is applied. 1 is a drive pulley, 2 is a main shaft, 4 is a drive motor, 5 is a transmission belt, and 6 is a drive belt.
Is a thread cutting cam, 8 is a thread cutting cam arm, 10 is a roller, and 1 is a roller.
1 is a thread cutting connecting rod, 13 is a thread cutting link, 16 is a thread cutting connecting rod, 17 is a shaft, and 30 is an actuator.

That is, in the thread cutting device of the cycle sewing machine in this embodiment, as shown in the drawing, the main shaft 2 screwed and fixed to the end portion so that the drive pulley 1 rotates integrally.
Are arranged so as to extend substantially horizontally on the upper part of the sewing machine. A drive motor 4 is arranged at a position directly below the drive pulley 1 at the end of the main shaft 2.

The drive motor 4 is composed of a servomotor or an electromotor whose rotation state is electrically controlled, and is stopped by a fixed number of stitches or a detection signal from a sensor. A transmission belt 5 is stretched between the output shaft of the drive motor 4 and the drive pulley 1.

A thread cutting cam 6 having a predetermined outer peripheral shape is screwed and fixed to the main shaft 2.
In the vicinity of the thread cutting cam 6, a thread cutting cam arm 8 is further provided so as to be swingable about an axis substantially parallel to the main shaft 2. A roller 10 is rotatably attached to one end portion 8a of the thread cutting cam arm 8.
No. 0 is arranged on the cam surface of the thread cutting cam 6 at a position where it can be pressed. A cam surface for giving a predetermined operation to the thread cutting cam arm 8 is formed on the outer peripheral surface of the thread cutting cam 6.

Further, an upper end of a thread cutting connecting rod 11 is rotatably connected to the other end 8b of the thread cutting cam arm 8. The thread trimming connecting rod 11 extends downward and its lower end has a substantially L-shape.
3 is rotatably connected. This thread trimming link 13
Is fixed to a shaft 17 rotatably supported by the arm machine frame so as to extend in a direction orthogonal to the main shaft 2.

A tension spring 25 is connected to one end of the thread cutting link 13 to apply a biasing force to the thread cutting connecting rod 11 in an upward direction. A thread cutting connecting rod 16 extending toward the thread cutting mechanism (not shown) is rotatably connected to the other end of the thread cutting ink 13. Therefore, the thread cutting cam 6 and the thread cutting cam arm 8
The thread cutting operation transmitted through the thread cutting connecting rod 11 is transmitted to the thread cutting mechanism by the thread cutting link 13.

An actuator 30, which is a solenoid or a cylinder, is arranged below another end 8c of the thread cutting cam arm 8 which extends below the one end 8a. That is, in the actuator 30, the tip end of the drive part 30a that can move forward and backward can be brought into contact with and separated from the other end 8c of the thread cutting cam arm 8 from below.

Since the thread trimming device of the cycle sewing machine is constructed as described above, first, from the start of one cycle of sewing to the middle thereof, the driving portion 30a of the actuator 30 is indicated by the arrow A.
Is moving upward, and the tip of the drive portion 30a contacts the other end 8c of the thread cutting cam arm 8 and pushes it up. As a result, the roller 10 of the one end portion 8a of the thread cutting cam arm 8 and the thread cutting cam 6 are held in a position where they do not come into contact with each other, so that the thread cutting operation is not performed.

Then, a predetermined cycle of the sewing operation, that is,
When the timing corresponding to the final needle of the 1-cycle sewing operation is reached, the drive unit 30a of the actuator 30 is
By moving the thread cutting cam arm 8 in the downward direction, the contact with the other end 8c of the thread cutting cam arm 8 is released, and the roller 10 is pressed against the outer peripheral surface of the thread cutting cam 6. As a result, the thread cutting cam arm 8 performs a predetermined swing motion based on the cam surface of the thread cutting cam 6. The swinging motion of the thread cutting cam arm 8 is transmitted to the thread cutting mechanism as a thread cutting operation by the thread cutting connecting rod 11 and the thread cutting link 13.
A predetermined thread cutting operation is performed by the thread cutting mechanism.

This thread trimming operation is performed when the sewing machine is stopped as shown in the timing chart of the relationship with the presser foot shown in FIG.
The operation of the actuator 30 by the solenoid or cylinder is controlled by the number of stitches from the signal of the drive motor 4 so that the thread cutting operation is performed with a slight delay from the front of the staple. When the sewing machine is stopped, the work clamp is raised.

Regarding the presser foot lifting mechanism (not shown),
The operation is controlled separately from the thread cutting mechanism by an appropriate actuator such as a solenoid or a cylinder.

As described above, in the thread trimming device of the cycle sewing machine according to the present invention, the driving portion 30a of the actuator 30 by the solenoid or the cylinder is caused to project during the sewing operation of one cycle, and the cam surface of the thread trimming cam 6 is driven. The thread trimming cam arm 8 is separated from the thread trimming cam arm 8 and the driving portion 30a of the actuator 30 is returned to the thread trimming cam 6 on the cam surface of the thread trimming cam 6 at the timing corresponding to the final needle of the sewing operation of one cycle. The cam arm 8 is brought into contact and a predetermined thread trimming operation is performed thereby, which is a system which is not connected to a conventional presser foot lifting mechanism.

Therefore, without using a conventional thread trimming control cam or the like, it is possible to perform thread trimming control satisfactorily for a long period of time with a simple structure and improve the reliability of the cycle sewing machine.

In the above embodiments, the solenoid or cylinder actuator is used, but the present invention is not limited to this, and other actuators may be used. Further, although one cycle has been described as an example of the predetermined cycle of the sewing operation, the present invention is not limited to this, and a predetermined cycle of a combination of half cycle and one cycle, or a cycle in which the half cycle or one cycle is further divided. Can be applied to. Further, the structure of the transmission mechanism from the thread cutting cam arm to the thread cutting mechanism, the structure of the presser lifting mechanism, and the like are arbitrary, and in addition, it is needless to say that the specific detailed structure and the like can be appropriately changed. is there.

[0036]

As described above, according to the thread trimming device of the cycle sewing machine of the present invention, the thread cutting cam arm is moved from the cam surface of the thread trimming cam by the operation of the driving portion of the actuator during the sewing operation of the predetermined cycle. When the timing corresponding to the final needle of the sewing operation of the predetermined cycle is reached, the thread cutting cam arm is brought into contact with the cam surface of the thread cutting cam by the operation of the actuator driving unit, and the predetermined thread is Since it is configured to perform the cutting operation and is not connected to the conventional presser foot lifting mechanism, it has a simple structure and does not have to use a thread trimming control cam like the conventional one, and can be used for a long period of time. The thread trimming control can be performed well, and the reliability of the cycle sewing machine can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an essential part showing an internal structure of a cycle sewing machine as an example to which the present invention is applied.

FIG. 2 is a timing chart showing the execution of thread cutting in relation to the presser foot.

FIG. 3 is a schematic perspective view of essential parts showing an example of the internal structure of a conventional thread trimming control device for a cycle sewing machine.

[Explanation of symbols]

 2 main shaft 4 drive motor 6 thread trimming cam 8 thread trimming cam arm 8a, 8b, 8c end 10 roller 11 thread trimming connecting rod 13 thread trimming link 30 actuator 30a driver

Continuation of the front page (72) Inventor Shoichi Shibuya 1-2-2 Kokuryo-cho, Chofu-shi, Tokyo Inside Juke Co., Ltd.

Claims (1)

[Claims] 1. A main shaft is rotationally driven by using a drive motor whose rotational state is electrically controlled, and a predetermined sewing operation is repeatedly performed every predetermined cycle. The movable blade is reciprocated. A thread trimming device of a cycle sewing machine having a thread trimming mechanism for performing thread trimming operation of a sewing thread, comprising: a thread trimming cam fixed to the main shaft; A thread trimming cam arm that transmits a predetermined thread trimming operation to the mechanism; and an actuator that contacts and separates from the thread trimming cam arm to contact and separate the thread trimming cam arm from the cam surface of the thread trimming cam. A thread cutting device for a cycle sewing machine, comprising: