JPH07666A - Control device for thread cutter driving cam of sewing machine - Google Patents

Abstract

PURPOSE:To provide a control device for thread cutter driving cam of sewing machine with small operating force and capable of more downsizing the whole mechanism, as a means for operating a thread cutter driving cam. CONSTITUTION:A control device for thread cutter driving cam of sewing machine has an axially movable thread cutter driving cam 21 integrally rotating with a driving shaft 3; a control cam 27 for controlling the axial movement of the thread cutter driving cam 21; and a miniature solenoid 35, for example, for controlling the rotation and stop of the control cam 27. This device is further provided with a thread cutter moving blade 1 rotating around a hook axis, and a thread cutter fixed blade 45 fixed to a sewing body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a thread cutting blade driving cam of a sewing machine.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in FIG.
The thread cutting blade drive cam A is a drive shaft B supported by the sewing machine main body.
And the roller D provided on the transmission arm C is not engaged in the sewing state. The transmission arm C is supported so as to be movable in the axial direction with respect to an axis E fixed to the sewing machine main body, and is pressed in the axial direction by a pressing spring F. As shown in FIG. 11, the solenoid G moves the transmission arm C in the axial direction against the pressing force of the pressing spring F at the start of thread cutting. As a result, the roller D provided on the transmission arm C engages with the cam surface of the thread cutting blade drive cam A,
As shown in FIG. 2 (a, b), it is known that the thread cutting movable blade H makes a reciprocating rotary motion and also cooperates with the thread cutting fixed blade J to perform a predetermined thread cutting operation.

[0003]

However, the exciting force of the solenoid G requires a force larger than the pressing force of the pressing spring F for returning the transmission arm C at the end of the thread cutting operation. . For this purpose, the solenoid G
Has a large excitation force and is large in size. Therefore, the conventional control device of this type has a problem that the manufacturing cost is high and it is difficult to downsize the entire thread cutting mechanism.

The present invention has been made in order to solve the above-mentioned problems, and as a control means of a thread cutting blade drive cam, a thread cutting blade drive of a sewing machine which has a small operating force and can be made smaller in size as a whole mechanism. It is to provide a control device for a cam.

[0005]

In order to achieve this object, the present invention has a moving thread cutting blade that cuts an upper thread and a lower thread in cooperation with a fixed thread cutting blade by performing a rotary reciprocating motion. In a sewing machine having the thread trimmer, the thread trimmer being rotatable integrally with the drive shaft, movably supported in the axial direction thereof, and having a drive cam for operating the movable thread cutting blade at a predetermined axial movement position. A blade drive cam, spring means for elastically arranging the thread cutting blade drive cam at a fixed position except the predetermined movement position in the axial direction, and rotatable on the drive shaft on one side of the thread cutting blade drive cam. And a control cam having an operation cam for moving the thread cutting blade drive cam in one direction of the axis against the spring means at a constant rotation position thereof, and a timing for starting the upper thread and lower thread cutting operation. To
And a control means for stopping the control cam at the constant rotation position.

[0006]

According to the present invention having the above-mentioned structure, the rotation of the control cam is stopped by the control means at a constant position of the rotation, and the thread cutting blade drive cam is caused to spring by the actuating cam of the control cam. By moving in the axial direction against the action, the drive cam causes the thread cutting movable blade to rotate and reciprocate, and by the cooperative action of the thread cutting movable blade and the thread cutting fixed blade, Cut the lower thread.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the thread-cutting moving blade 1 is fixed to a holder 5 which makes a reciprocating rotation about a drive shaft 3. The holder 5 and the transmission arm 7 are connected by a linkage 9, and the transmission arm 7 is rotatably supported by a shaft 11 fixed to the machine frame of the sewing machine. The swing arm 15 is rotatable integrally with a shaft 17 supported by the machine frame of the sewing machine, and is interlocked with the transmission arm 7 via the angular roller 13. The roller 19 provided on the swing arm 15 is configured to reciprocate the swing arm 15 by the drive cam 21A of the thread cutting blade drive cam 21 during the thread cutting operation. At the position shown in FIG. 1, it does not engage with the drive cam 21A of the thread cutting blade drive cam 21.

As shown in FIG. 3, the thread cutting blade drive cam 2
1 has a key groove 21B in a fitting hole with the drive shaft 3, and a pin 23 fitted to both the key groove 21B and the drive shaft 3 rotates integrally with the drive shaft 3 and has an axial direction. It is movably supported by. Further, the thread cutting blade drive cam 21 has a concave portion 21C on the side surface which is in contact with the control cam 27. The pushing spring 25 presses the thread cutting blade drive cam 21 in the axial direction toward the right side in FIG. 1, and the axial positions of the thread cutting blade drive cam 21 and the control cam 27 are fixed to the drive shaft 3. It is kept constant by a retaining ring 29.

The control cam 27 is rotatably supported by the drive shaft 3, and during the rotation of the drive shaft 3, friction control of the contact surface with the thread cutting blade drive cam 21 causes the thread cutting blade drive cam 21 to rotate. Also, the structure is such that it rotates integrally with the drive shaft 3. Further, the control cam 27 has a convex portion 27A for abutting against the solenoid stopper 31 on the outer peripheral portion thereof to stop its own rotation at a constant rotation position, and the thread cutting blade in a state of being stopped at the constant rotation position. The convex actuating cam 27B that moves the drive cam 21 in the axial direction against the pressing force of the pressing spring 25 and the stopper 41 that rotates integrally with the swing arm 15 and the shaft 17 come into contact with the self-rotation. And a protrusion 27C for stopping. The push spring 33 is
The control cam 27 and the thread cutting blade drive cam 21 are pressed by a spring 25.
Is pressed in the axial direction against the pressing force of, but the pressing force is set lower than the pressing force of the pressing spring 25,
It does not affect the axial position of the thread cutting blade drive cam 21 and the control cam 27 which are held by the push spring 25 and the retaining ring 29.

The solenoid stopper 31 is rotatably supported by a solenoid holder 39. When the solenoid 35 is excited at the start of the thread cutting operation, the control cam 27 is activated.
Although it is rotated to a position where it can be prevented from rotating, it is held by the torsion spring 37 at the position shown in FIG. 1 where it does not contact the convex portion 27A of the control cam 27 in the sewing state. The pressing spring 25 constitutes a spring means for elastically disposing the thread cutting blade drive cam 21 at a fixed position in the axial direction, and includes a solenoid stopper 31 and a solenoid 35.
Constitutes a control means for stopping the control cam 27 at a constant rotational position. The control means described above can be replaced with a pulse motor, a linear motor, a manually operated member, or the like.

This embodiment is constructed as described above.

Next, the thread cutting operation based on the above construction will be described.

The layout of the members shown in FIG. 1 is in the sewing operation or in the stopped state. First, when the thread cutting operation is instructed, the solenoid 35 is excited to rotate the solenoid stopper 31 to a position where it can come into contact with the outer peripheral projection 27A of the control cam 27. The control cam 27, which started to rotate together with the drive shaft 3 and the thread cutting blade drive cam 21 at the same time as the excitation of the solenoid 35, has the convex portion 27A of the control cam 27.
When it comes into contact with 1, it stops at the position shown in FIG.
From this point of time, the drive shaft 3 and the thread cutting blade drive cam 21 continue to rotate, and the inclined surface of the convex actuating cam 27B of the control cam 27 which is stopped is changed to the concave portion 21C of the thread cutting blade drive cam 21.
While climbing as shown in FIG. 4, the thread cutting blade drive cam 21
Starts to move to the left in the axial direction against the pressing force of the pressing spring 25, and finally, as shown in FIG. 6, it is provided on the drive cam 21A of the thread cutting blade drive cam 21 and the swing arm 15. The roller 19 and the roller 19 are engaged with each other in the axial direction.

From this state, the drive shaft 3 and the thread cutting blade drive cam 21 continue to rotate, and as shown in FIGS. 7A and 7B, the swing arm 15 is driven by the drive cam with which the roller 19 abuts. According to the cam lift of 21A, the thread cutting movable blade 1 is rotated and reciprocated through the angular roller 13, the transmission arm 7, the connecting rod 9, the holder 5, and the like. During the rotary reciprocating motion, the thread cutting movable blade 1 cuts the upper thread and the lower thread by the cooperation of the thread cutting fixed blade 45 to end the thread cutting operation. After this thread cutting, the thread cutting movable blade 1 is linked with the holder 5 9
The force of the pulling spring 43 urged to return to the rotational position in the sewing state.

It should be noted that, while the thread cutting movable blade 1 makes a rotational reciprocating motion by the cam lift of the drive cam 21A, the thread cutting blade drive cam 21 is pushed by the load resistance given by the roller 19 to the drive cam 21A. The pressing force of 25 is invalidated, and a fixed state occurs in the axial direction. If the thread cutting blade drive cam 21 continues to rotate in this state, the recess 21
The convex actuating cam 27B of the control cam 27 is pushed to C by the push spring 33.
As shown in FIG. 8, it falls due to the axial pressing force of. At this time, the control cam 27 moves to the left in the axial direction and contacts the thread cutting blade drive cam 21. At this point, the contact state between the solenoid stopper 31 and the convex portion 27A of the control cam 27 is released.

Since the contact state of the control cam 27 is released, the control cam 27 restarts its rotation due to the frictional resistance with the thread cutting blade driving cam 21, but as shown in FIG.
Swinging arm 15 that reciprocates by the cam lift of
The stopper 41 works in conjunction with the projection 27C of the control cam 27.
Since it rotates to a position where it comes into contact with, the rotation is stopped again. The control cam 27 remains rotated until the end of thread cutting. Immediately after the roller 19 provided on the rocking arm 15 receives the action of the maximum cam lift of the drive cam 21A (immediately after the thread cutting movable blade 1 and the thread cutting fixed blade 45 cut the upper thread and the lower thread), The fixed state of the thread cutting blade drive cam 21 in the axial direction is released when the load resistance of the roller 19 to the drive cam 21A disappears.

At the time of releasing the fixed state, the push spring 2
Due to the axial pressing force of 5, the thread cutting blade drive cam 21 and the control cam 27 resist the pressing force of the pressing spring 33, and
It is pushed back to the state position as shown in. Further, the solenoid 35 finishes its excitation until the pushing spring 25 moves the thread cutting blade drive cam 21 and the control cam 27 to the sewing state position from the start of the excitation against the pushing force. At this point, the thread cutting operation by all the members ends.

[0019]

As is clear from the above description, according to the present invention, the operating force of the control cam for controlling the movement of the thread cutting blade drive cam can be minimized.
There are excellent effects such that the control cam portion can be downsized and the thread cutting mechanism can be downsized.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present apparatus.

FIG. 2 is a configuration diagram of a drive portion of a thread cutting movable blade.

FIG. 3 is a cross-sectional view of a thread cutting blade drive cam.

FIG. 4 is an explanatory view of the operation of this device.

5 is a cross-sectional view taken along line ZZ in FIG.

FIG. 6 is an operation explanatory view of the present device.

FIG. 7 is an explanatory diagram of the operation of this device.

FIG. 8 is an operation explanatory view of the present apparatus.

FIG. 9 is a configuration diagram of a conventional control device.

FIG. 10 is a configuration diagram of a conventional control device.

FIG. 11 is an operation explanatory view of a conventional device.

FIG. 12 is an operation explanatory view of a conventional device.

[Explanation of symbols]

 1 Thread Cutting Moving Blade 3 Drive Shaft 21 Thread Cutting Blade Drive Cam 21A Drive Cam 25 Push Spring 27 Control Cam 27B Actuating Cam 31 Solenoid Stopper 35 Solenoid 45 Thread Cutting Fixed Blade

Claims (1)

[Claims] 1. A sewing machine having a moving thread cutting blade that cuts an upper thread and a lower thread in cooperation with a fixed thread cutting blade by performing a rotary reciprocating motion, and is rotatable integrally with a drive shaft. A thread cutting blade drive cam that is movably supported in the axial direction and has a drive cam for operating the movable thread cutting blade at a predetermined axial movement position; and the thread cutting blade drive cam in the axial direction. Spring means for elastically arranging the thread cutting blade at a fixed position except the predetermined moving position of the thread cutting blade, and the thread cutting blade at the fixed rotation position rotatably provided on the drive shaft at one side of the thread cutting blade drive cam. A control cam having an actuating cam for moving the drive cam against the spring means in one direction of the axis, and a control for stopping the control cam at the constant rotational position at the start timing of the cutting operation of the upper thread and the lower thread. Means and Control device for thread cutting blade drive cam of the sewing machine, characterized in that the.