JP2595234Y2 - 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 the lower thread pulled out from the inner hook of the horizontal hook of the sewing machine and the upper thread hooked around the sword 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 As a thread cutting device, FIGS.
The following are known. The automatic thread cutting device includes a lower thread Y1 pulled out from 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.
Is controlled by the descending looper 3, and the upper thread Y2 and the lower thread Y1 are pulled by the moving knife 4 and cut with the fixed knife 5 .

By the way, the moving knife 4 is normally engaged with a cutting roller 8 and a cutting plate 9 supported by one of the thread cutting links 7 of the thread cutting links 6 and 7 supporting the moving knife 4. Is in a standby state. The detaching plate 9 has
Disconnecting link 10 for engaging and disengaging with disconnecting roller 8
Are connected. As shown in FIG. 5, the disconnection link 10 is further linked to the operation lever cam 26 via three links 23, 24, 25.

In this thread cutting device, when cutting the upper thread Y2 and the lower thread Y1, first, the operator lowers the operation lever 27 to rotate the operation lever cam 26, and moves the disconnection link 10 in the direction of the arrow. The detaching plate 9 is rotated to release the engagement with the detaching roller 8. 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. The moving knife 4 is connected to the cam 16
The lower thread Y1 that moves right and left following the shape of the inner hook 1 and the upper thread Y2 that has turned around the inner hook 1 is hooked by the hook 4a.
And come back. 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 is stopped, and if the operator returns the operation lever 27 to its original position, the detaching plate 9 is disengaged by the detaching spring. 2
The moving knife 4 returns to the standby position by climbing on the cutting roller 8 with a force of 0.

[0005]

[Problems to be solved by the invention]
Prior to the cutting of the upper thread Y1 and the lower thread Y1, the operator has to operate the operation lever 27, which is not a completely automatic thread cutting device.

The present invention aims to provide a fully automated automatic yarn cutting device.

[0007]

In order to achieve the above object, an automatic thread cutting device according to the present invention comprises a fixed knife, a thread cutting cam, a moving knife biased in the direction, and a support link thereof. A cam portion including a provided cutting roller, a cutting link, and a portion where the distance from the support shaft gradually increases and becomes constant is formed at one end, and one end of the cutting link is connected to the other end. And a stepping motor and an operating gear engaged with the gear, the cam section being biased to engage with the cutting roller, and having a predetermined play to provide the other end of the disconnecting link. And the operating gear.

[0008]

In the automatic thread cutting device configured as described above, when the thread trimming switch is turned on after the sewing is completed, the stepping motor rotates in the direction for releasing the engagement between the cutting plate and the cutting roller. After starting and clearing the play between the other end of the disconnection link and the operating gear and engaging with each other, the disconnection link moves and the disconnection plate rotates. Then, when the detaching plate comes off the detaching roller, the main motor rotates to rotate the thread cutting cam, and the thread cutting operation is performed. When the rotation of the main motor stops, the stepping motor starts rotating in the opposite direction, clears the play between the other end of the disconnecting link and the operating gear, engages with each other, and then moves the disconnecting link in the opposite direction. The cutting plate moves and rotates in the opposite direction, rides on the cutting roller, and the biasing force of the cutting plate removes the cam section where the distance of the cutting plate from the spindle is constant, and the roller is removed. The cutting board rotates as it rolls,
The moving knife returns to the standby position. At that time, the stepping motor stops before the disconnecting plate enters the standby state, and the disconnecting plate is rotated by the urging force, but the force of the disconnecting link is between the other end of the disconnecting link and the operating gear. There is no play, so it is not transmitted to the stepping motor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic yarn cutting device according to the present invention will be described with reference to FIGS.

This automatic thread cutting device is controlled by 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
A basic structure is adopted in which the moving knife 4 pulls 1 and cuts it with the fixed knife 5. The moving knife 4 is brought into a standby state by the engagement of the cutting roller 8 and the cutting plate 9 supported by one of the thread cutting links 7 of the thread cutting links 6 and 7 supporting the moving knife 4. You. A disconnecting link 10 for engaging and disengaging the disconnecting roller 8 is connected to the disconnecting plate 9. Further, the disconnect link 10
Is connected to a gear 14 of a stepping motor 13 via an operation plate 11 and an operation gear 12.

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 cut-off plate 9 is swingably supported by the machine frame F by a support shaft 19, and has a portion at the tip end where the distance from the support shaft 19 gradually increases as shown in FIG. And a cam portion 9a composed of a portion that becomes constant.
The other end is connected to the disconnect link 4. And
The detaching plate 9 is separated from the cam portion 9a by the detaching link spring 20.
Are urged in the direction of riding on the cutting roller 8, that is, in the counterclockwise direction. When the moving knife 4 is returned to the standby state, the force of the disconnecting link spring 20 is applied to the portion of the cam portion 9a where the distance from the support shaft 19 becomes constant after the disconnecting roller 8 rides on the cam portion 9a. It is sufficient that the cutting roller 8 is small enough to rotate.

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 to remove 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 right end of the disconnecting link 10 is pivotally connected to one end of an operating plate 11, and an operating gear 12 is rotatably supported at the other end of the operating plate 11. Also, the operating plate 11
Abutments 1 extending perpendicularly to its body
1a is provided. On the other hand, the gear portion 1 of the operating gear 12
On the opposite side of 2b, a contact portion 12a having a width smaller than the interval between the contact portions 11a of the operation plate 11 is provided. Therefore, after the operation gear 12 rotates by a certain angle, one of the operation gears
The second contact portion 12a and one contact portion 11a of the operation plate 11 come into contact with each other. In addition, instead of such a connection structure, a long hole is formed in the contact portion 12a of the operating gear 12,
Alternatively, a shaft protruding from the right end of the disconnecting link 10 may be directly inserted and engaged.

The gear portion 12b of the operating gear 12 meshes with the gear 14 of the stepping motor 13, and the stepping motor gear 14 is provided with a shielding plate 21. On the other hand, at a predetermined position of the rotation path of the shielding plate 21,
A detection plate 22 having a U-shaped detection unit is provided.
The installation position of the detection plate 22 is set to be in a standby state in which the cutoff plate 9 is cut off and rides on the roller 8 when the shield plate 21 rotates and shields the detection unit.

When the moving knife 4 is returned to the standby state, the stepping motor 13 is moved before the stopper portion 9a of the cutting plate 9 hits the cutting roller 8 after the cutting roller 8 rides on the cutting plate 9. It is set to stop rotation.
The rotation of the disconnecting plate 9 after the stepping motor 13 is stopped is performed by the force of the disconnecting link spring 20.

In the automatic thread cutting device configured as described above, when the operator turns on a thread trimming switch (not shown) after the sewing is completed, the stepping motor 13 starts rotating in a cutting direction indicated by an arrow in FIG. . After the contact portion 12a of the operating gear 12 hits the right contact portion 11a of the operating plate 11, the disconnecting link 10 moves in the direction of the arrow, and the disconnecting plate 9 rotates clockwise. And
When the separating plate 9 comes off the separating roller 8, the main motor rotates and the lower shaft 18 rotates, and the thread cutting operation is performed as described above. When the main motor stops rotating,
The stepping motor 13 starts rotating in the opposite direction. After the contact portion 12a of the operating gear 12 comes into contact with the left contact portion 11b of the operating plate 11, the disconnecting link 10 moves to the left, and the disconnecting plate 9 rotates counterclockwise to disconnect the disconnecting roller 8. , And by the force of the disconnecting link spring 20, the portion of the cam portion 9a at which the distance from the shaft 19 is constant is removed, and the detaching plate 9 rotates so that the roller 8 rolls. The moving knife 4 hits the stopper portion 9b and returns to the standby position. At that time, the stepping motor 13 stops before the stopper portion 9a of the disconnecting plate 9 hits the disconnecting roller 8, and the disconnecting plate 9 is rotated by the force of the disconnecting link spring 20. At that time, the operating plate 11 also rotates, so that the contact portion 11a of the operating plate 11 and the operating gear 1
A gap is generated in the second contact portion 12a, so that no external force is applied to the stepping motor 13 any longer.

Note that, as shown in FIG.
If the moving knife 4 is returned to the standby state, the stopper portion 9 of the cut-off plate 9 is provided.
It is necessary to stop the rotation of the stepping motor 13 at the moment when “a” hits the cutting roller 8. If this timing does not match, the stopper 9a is cut off and the
, The stepping motor 13 tries to rotate and the stepping motor 13 loses synchronism, which is not preferable. In order to prevent the loss of synchronism, it seems to be sufficient to set the rotation of the stepping motor 13 before the stopper portion 9a comes off and hits the roller 8, but in that case, the stepping motor 13 always maintains the state. It is necessary to keep a large holding current flowing even when thread trimming is not activated,
The stepping motor 13 generates heat, which is not preferable. When the disconnecting link 10 is directly connected to the operating gear 12 ′, when the origin of the stepping motor 13 is detected, the disconnecting plate 9 rotates together with the rotation of the stepping motor 13. The unloading roller 8 is also undesirably cut off.

[0022]

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

That is, the cutting of the upper thread and the lower thread after the completion of sewing can be completely automated. In addition, since there is play between the disconnecting link and the operating gear, the stepping motor does not step out or generate heat in the standby state. There is no possibility that the roller is cut off from the board.

[Brief description of the drawings]

FIG. 1 is a plan view of the automatic yarn cutting device of the present invention.

FIG. 2 is a plan view of a cutting plate in the automatic yarn cutting device of the present invention.

FIG. 3 is a plan view when a disconnection link is directly connected to a gear of a stepping motor.

FIG. 4 is a plan view of a conventional automatic yarn cutting device.

FIG. 5 is a front view illustrating a connection state from a disconnection link to an operation lever cam in a conventional automatic thread cutting device.

[Description of Signs] 4 Moving Knife 5 Fixed Knife 6 Support Link 7 Support Link 8 Disconnect Roller 9 Disconnect Plate 9a Cam Part 10 Disconnect Link 12 Operating Gear 13 Stepping Motor 14 Stepping Motor Gear 16 Thread Trimming Cam 19 Support Shaft

Claims (1)

(57) [Scope of request for utility model registration] The distance between the fixed knife, the thread cutting cam, the moving knife urged in the direction, the cutting roller provided on the support link, the cutting link, and the support shaft is gradually increased. A cam plate formed of a portion that becomes larger and a portion that becomes constant is formed at one end, and one end of a cutting link is connected to the other end, and the cam portion is cut off and biased to engage with the cutting roller. An automatic thread cutting device comprising a stepping motor and an operating gear engaged with the gear, and having a predetermined play to connect the other end of the disconnection link to the operating gear.