JP2572662Y2 - Automatic thread cutting device - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention uses a moving knife and a fixed knife to cut a lower thread pulled out from the inner hook of the horizontal hook of the sewing machine and an upper thread hooked on the point of the outer hook and rotating around the inner hook. The present invention relates to an automatic yarn cutting device.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional yarn cutting device.
The following are known. The automatic thread cutting device includes a lower thread Y1 drawn from a lower thread bobbin B of an inner shuttle 1 of a horizontal shuttle.
The upper thread Y2, which is hooked on the sword tip 2a of the outer hook 2 and turns around the inner hook 1, is held down by the descending looper 3 and regulated, and the upper thread Y2 and the lower thread Y1 are drawn by the moving knife 4. It cuts between the fixed knife 4.
Usually, the thread cutting links 6 and 7 for supporting the moving knife 4 are provided.
The moving knife 4 is in a standby state by the engagement of the cutting roller 8 supported by the one thread cutting link 7 with the cutting plate 9. A disconnecting link 10 for engaging and disengaging the disconnecting roller 8 is connected to the disconnecting plate 9.

In this thread cutting device, when cutting the upper thread Y2 and the lower thread Y1, first, the disconnection link 10 is moved in the direction of the arrow to rotate the disconnection plate 9 to engage the disconnection roller 8. Cancel the match. When the engagement between the cutting plate 9 and the cutting roller 8 is released, the lower shaft 18 rotates, and the moving knife 4 moves to the right by the force of the thread cutting link spring 15 so that the thread cutting roller 17 It engages with the cam portion 16a of the cutting cam 16. Then, the moving knife 4 moves right and left following the shape of the cam portion 16a, and hooks the lower thread Y1 coming out of the inner hook 1 and the upper thread Y2 that has turned around the inner hook 1 onto the hook portion 4a and returns. Come. Then, when the blade portion 4b and the fixed knife 5 match, the yarns Y1 and Y2 are cut. Finally, when the thread cutting roller 8 completely rides on the cam portion 16a of the thread cutting cam 16, the rotation of the lower shaft 18 stops.

[0004]

[Problems to be solved by the invention]
When the moving knife 4 hooks the upper thread Y2 and the lower thread Y1 during the thread cutting operation and returns, the lower thread Y1 is pulled out from the bobbin B. Since the lower thread Y1 also rotates by inertia, the lower thread Y1 may be in a slack state, jump out of the upper opening of the inner hook 1, and hinder sewing after thread cutting.

An object of the present invention is to prevent the bobbin bobbin from rotating by inertia after the operation of pulling out the lower thread by the moving knife at the time of cutting the upper thread and the lower thread in the sewing machine.

[0006]

In order to achieve the above object, the automatic yarn cutting device according to the present invention restricts the upper and lower yarns by pressing the upper and lower yarns onto the inner hook of a horizontal hook while controlling the movement. One end is urged so as to protrude to the lower position of the looper on the inner hook, and the other end abuts on the bobbin in the inner hook to regulate the rotation by the lowering of the looper. It has an anti-spin body.

[0007]

In the automatic yarn cutting device constructed as described above, when the looper descends on the inner hook of the horizontal hook when cutting the upper thread and the lower thread, the anti-spinning body moves into the inner hook and moves to the bobbin. Abut On the other hand, the upper thread and the lower thread are drawn to the moving knife and cut between the moving knife and the fixed knife. The lower thread is pulled out by rotating the bobbin due to the pulling, but the bobbin does not rotate more than necessary because the anti-spin body is in contact with the bobbin.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of this automatic yarn cutting device is the conventional structure shown in FIG. 3. First, the basic structure will be described.

The automatic thread cutting device comprises a looper 3 which descends a lower thread Y1 pulled out of an inner shuttle 1 of a horizontal shuttle and an upper thread Y2 hooked around a sword tip 2a of an outer shuttle 2 and rotating around the inner shuttle 1. The upper thread Y2 and the lower thread Y
1 is pulled by the moving knife 4 and cut between the fixed knife 5 and a cutting roller 8 supported by one of the thread cutting links 7 of the thread cutting links 6 and 7 for supporting the moving knife 4. The moving knife 4 is brought into a standby state by the engagement with the detaching plate 9. The separating plate 9 includes a separating roller 8.
And a disconnecting link 10 for controlling engagement and disengagement.

The inner shuttle 1 is rotatably placed on the race surface of the outer shuttle 2, and is prevented from rotating by a rotation restricting body 11 attached to the frame, as shown in FIG.
An opening 1a for receiving the lower thread bobbin B is formed on the upper surface of the inner shuttle 1, and a tension generating member 12 for applying tension to the lower thread Y1 is attached to a part of the opening 1a. I have. On the other hand, the outer hook 2 is horizontally rotated in synchronism with the lower shaft 18 by a screw gear (not shown) fixed to the lower shaft 18, and the tip of the needle 2a captures the loop of the upper thread Y2 formed on the needle. Therefore, the upper thread Y2 goes around the inner hook 1 and is entangled with the lower thread Y1 protruding from the tension generating member 12 of the inner hook 1 to form a seam.

The moving knife 4 is pivotally attached to the other end of each of the thread cutting links 6 and 7 whose one end is swingably supported by the machine frame F. A thread trimming link spring 15 for urging the moving knife 4 in the direction of the thread trimming cam 16 is hung between the thread trimming link 6 and the machine frame F. A cut-off roller 8 and a thread-cutting roller 17 are attached to an intermediate portion of the other thread-cutting link 7 and a pivotally connected portion to the moving knife 4, respectively.

The moving knife 4 has a hook 4a for hooking the lower thread Y1 and the upper thread Y2 when moving to the right, and a blade 4b engaging with the fixed knife 5 to cut the lower thread Y1 and the upper thread Y2. Are integrated at a predetermined interval. Therefore,
When the moving knife 4 moves to the right, the fixed knife 5 enters between the hook portion 4a and the blade portion 4b.

The thread cutting cam 16 is fixed to the tip of the lower shaft 18, and the cam 16a is cut at a predetermined phase so that the moving knife 4 moves to the right and then to the left.

An intermediate portion of the disconnecting plate 9 is swingably supported by the machine frame F by a support shaft 19, a cam portion is formed at the tip, and the other end is connected to the disconnecting link 4. I have.
The disconnecting plate 9 is urged by the disconnecting link spring 20 in a direction in which the cam portion 9a is detached and rides on the roller 8, that is, counterclockwise.

The moving knife 4 is normally in a standby state by the engagement of the detaching roller 8 and the detaching plate 9, but when the upper thread Y2 and the lower thread Y1 are cut, the detaching link 10 is used. Is moved in the direction of the arrow to rotate the disconnecting plate 9 clockwise, and the engagement with the disconnecting roller 8 is released. Lower shaft 18, thread cutting cam 16 interlocked with it
Is rotated by the detachment plate 9 coming off the detaching roller 8, and is stopped after the thread cutting operation is performed.

Accordingly, when the engagement between the cutting plate 9 and the cutting roller 8 is released, the moving knife 4 is moved to the thread cutting link spring 15.
The thread cutting roller 17 is moved to the right by the force, and engages with the cam portion 16a of the thread cutting cam 16, moves right and left following the shape of the cam portion 16a, and moves the lower thread Y1 and the upper thread Y2. It is hooked on the hook 4a and returns. And the blade part 4b
Is engaged with the fixed knife 5, the threads Y1 and Y2 are cut, and when the thread cutting roller 17 completely rides on the cam portion 16a of the thread cutting cam 16, the rotation of the lower shaft 18 is stopped.

The looper 3 is lowered by a looper operating portion (not shown) attached to the disconnecting link 10. Accordingly, when the thread is cut, the cutting plate 9 comes off the cutting roller 8 when the thread is cut, and the thread cutting roller 17 is lowered by the force of the thread cutting link spring 15 at the same time that the thread cutting roller 17 comes into contact with the thread cutting cam 16. Of the horizontal portion 1b.

Next, with reference to FIGS. 1 and 2, a description will be given of an anti-spin body which is a main part of the automatic yarn cutting device of the present invention.

The anti-spinning body 13 has a protruding portion 13a which can protrude above a hole 1c formed in the horizontal portion 1b outside the lower thread bobbin housing portion of the inner hook 1, and a hole 1e in a side wall 1d of the inner hook 1. A bobbin abutment portion 13b having an elasticity (for example, made of plastic and bent as shown in FIG. 1 to be an elastic body) having an elasticity capable of protruding inside the lower thread bobbin housing portion, It is rotatably supported by a support shaft 14 at an outer portion of the yarn bobbin storage portion. Normally, the protrusion 13a protrudes above the protrusion hole 1c by the anti-spin body spring 19, and the tip of the bobbin contact portion 13b is
Is not in contact with In addition, the protrusion 13a has the hole 1c.
The protruding portion is a position where the looper 3 descending at the time of thread cutting hits.

In addition, the lower end of the anti-spinning body 13 is urged to project to the lowered position of the looper 3 on the inner hook 1, and the lower end of the lower thread bobbin B in the inner hook 1 is lowered by the lowering of the looper 3. Any structure may be used as long as it can abut the surface.

In the automatic thread cutting device having the above-described structure, after the sewing operation is completed, the operator turns on a thread cutting switch (not shown), whereby the disconnecting link 10 moves in the direction of the arrow, and the detaching plate 9 is moved. Rotates clockwise. Then, the cutting-off plate 9 comes off the cutting-off roller 8, and the thread-cutting roller 17 comes into contact with the thread-cutting cam 16 by the force of the thread-cutting link spring 15, and at the same time, the looper 3 descends and the horizontal portion 1 of the inner shuttle 1 is moved.
b. Then, the protrusion 13 b is pushed by the looper 3, and the anti-spin body 13 rotates against the force of the anti-spin body spring 19. Therefore, the bobbin contact portion 14
a comes into contact with the lower thread bobbin B and gives a rotational resistance to the lower thread bobbin B. Then, the main motor rotates and the lower shaft 18 rotates, and the thread cutting operation is performed as described above.

[0022]

[Effects of the Invention] The present invention is configured as described above, and has the following effects.

That is, when cutting the upper thread and the lower thread, the anti-spinning member abuts on the lower thread bobbin to regulate the rotation thereof.
Unnecessary rotation of the bobbin can be prevented. Therefore, normal sewing can be performed even after the thread is cut.

[Brief description of the drawings]

FIG. 1 is a sectional view of an inner shuttle portion of the automatic yarn cutting device according to the present invention.

FIG. 2 is a plan view of an inner shuttle portion of the automatic yarn cutting device according to the present invention.

FIG. 3 is a plan view of the automatic yarn cutting device.

FIG. 4 is a front view of an inner hook part in a conventional automatic thread cutting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner hook 3 Looper 4 Moving knife 5 Fixed knife 13 Bobbin anti-rotation body B Bobbin thread bobbin Y1 Bobbin thread Y2 Upper thread

Claims (1)

(57) [Scope of request for utility model registration] An upper thread and a lower thread are held down on an inner shuttle of a horizontal shuttle by a lowering looper, and are cut by a moving knife and a fixed knife. An automatic thread cutting device having an anti-spin device that is urged to protrude to a position, and whose rotation abuts the bobbin in the inner hook when the looper is lowered to restrict rotation.