JPH07100274A - Button hole sewing machine with needle thread cutting and tightening device - Google Patents

Abstract

PURPOSE: To provide a needle thread cutting/fastening device for button-holing sewing machine with which the perfect result can be easily provided in the case of sewing the end of a needle thread. CONSTITUTION: In order to functionally divide the lateral action and open action of a thread cutting/fastening device 27 and to control these two actions, a cam mechanism 18 has respectively peculiar cams 13 and 15, and the positions of these cams 13 and 15 can be at least partially, mutually and relatively adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewn product moving frame which can be moved forward and backward together with a holding part, and a needle bar which carries a needle for guiding a thread and oscillates laterally with respect to the feed direction of the sewn product moving frame. , Has a thread cutting / tightening device that cuts the upper thread at the end of the sewing cycle and brings the thread end on the stockpiling side to the front of the needle to enable sewing for the start of the next sewing cycle. The device is arranged on a carrier that is movable in the lateral direction and parallel to the feed direction of the sewn product moving frame, and holds the lateral movement and the opening motion of the thread cutting / tightening device by the holding of the sewn product moving frame. The present invention relates to a buttonhole sewing machine which is controllable by a cam mechanism arranged in the section.

[0002]

2. Description of the Related Art According to German Patent No. 961936, scissors-like needle thread cutting controlled by a sewing mechanism.
Buttonhole sewing machines with a tightening device are known. This upper thread cutting / tightening device cuts the upper thread at the end of the sewing work cycle, holds the thread end on the stockpile side, and prevents the thread from falling off at the start of the next sewing. Further, the needle thread cutting / tightening device brings the thread end to the front of the needle at the start of sewing, and the thread end is sewn when forming the first buttonhole overhang. For this reason, the thread cutting / tightening device is arranged on a carrier that is movable in the longitudinal direction and the lateral direction with respect to the feed direction of the sewn product moving frame. The carrier cooperates with a cam fixed to the holding part of the sewn product moving frame. The cam is formed with a groove, which cooperates with a stop pin provided on the movable cutter of the cutting device.

When the cutting / tightening device is moved in the longitudinal direction at the start of sewing, the carrier of the cutting / tightening device is
It slides along the diagonally extending guide surface of the cam. This causes the cutting and tightening device to move slightly laterally in the feed direction of the sewn product moving frame. As a result, the tightened and held thread end is pulled toward the left buttonhole edge. During sewing of this first buttonhole overlock, the sewn product moving frame, together with the cam, moves relative to the stationary carrier in this direction. In this case, the oblique guide surface of the cam moves the cutting and clamping device further laterally. The stop pin of the movable cutter then reaches the working range of the groove of the cam, which releases the cutting and tightening device and releases the yarn end.

The shape and size of the cam are chosen so that the opening time of the thread clamp ensures a satisfactory sewing of the thread end with respect to the lateral movement of the cutting and clamping device or the lateral pivoting position. That is, the cutting and tightening device must be sufficiently separated from the home position at the time of opening. This is because, if not separated, the thread end penetrates into the buttonhole hole after cutting the buttonhole. On the other hand, the cutting and tightening device must not rotate too far outwards. This is because if it is rotated too much, the end portion of the thread end may slip out laterally from the left buttonhole overlock. However, slight deviations in the shape and size of the cams and / or increased play between the parts that are movable relative to each other may lead to unsatisfactory results regarding the sewing of thread ends and improve the sewing results. In order to do this, the cam must be additionally machined.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to construct a needle thread cutting / tightening device for a buttonhole sewing machine so that satisfactory results can be easily obtained when sewing the needle thread ends. is there.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention functionally divides the lateral movement and the opening movement of the yarn cutting / tightening device to control these two movements. It is characterized in that each mechanism has its own cam, which cams are at least partially adjustable relative to each other.

A second aspect of the present invention relates to the structure of the cam mechanism according to the present invention. By adjusting the position of the control plate,
The position of the yarn end at the time of opening the cutting / tightening device is fixed.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The basic construction and operation of the buttonhole sewing machine according to the present invention are described in the above-mentioned German Patent No. 96193.
It corresponds to that of the sewing machine disclosed in Japanese Patent No. 6, and therefore detailed description thereof will be omitted.

A buttonhole sewing machine according to the present invention has a sewn product moving frame 1 for holding a sewn product from above. The sewn product moving frame 1 is rotated by a fork member 2 at the front end of a carrying lever 3 which is movable in the longitudinal direction and is rotatable around an axis extending horizontally in the feed direction V of the sewn product moving frame 1. It is movably supported.

The needle bar 4 of which only a part is shown, together with the needle 5 for guiding the thread, carries out an oscillating movement in the lateral direction with respect to the feed direction V of the sewn product moving frame 1.

On the side of the carrying lever 3 opposite to the fork member 2, a square member 6 is fixed so that its position can be adjusted. The horizontally projecting leg plate 7 of the prismatic member 6 has a shoulder 8 with a stepped slope. A flat control plate 10 is arranged in the flat cut-out portion 9 of the leg plate 7 so that its position can be adjusted by a screw 11. The control plate 10 likewise has a guide surface 12 extending obliquely. The position adjusting direction of the control plate 10 is horizontal with respect to the feeding direction V of the sewn product moving frame 1. A leg plate 7 with a stepped shoulder 8 and a control plate 10 with a guide surface 12 form a cam 13.

On the lower surface of the leg plate 7, there is arranged a lever 14 which is rotatable around a vertical axis. The lever 14 has an oblique shoulder portion 16 forming another cam 15 and an operation plate 17 protruding downward. Both cams 13 and 1
Reference numeral 5 forms a cam mechanism 18.

A carrier 20 is fixed to a drive rod 19 which is movable in the longitudinal direction and rotatable about a vertical axis and a horizontal axis. An L-shaped cutter 21 is screwed to the carrier 20. A cutting edge is formed at the front end of the cutter 21. The cutter 21 includes an opposing cutter 2 that is relatively rotatable with respect to the cutter 21.
Two are provided. A blade edge is formed at the L-shaped front end of the facing cutter 22. This cutting edge, together with the cutting edge of the stationary cutter 21, forms a scissors-like cutting device. By means of a pin 23 and a screw 24 (both of which project through a hole (not shown) provided corresponding to the facing cutter 22 and protrude) corresponding to the facing cutter 22, the blade tip of the facing cutter 22 is fixed. A leaf spring 25 is arranged which is pressed with a pretensioning force. Leaf spring 25
Together with the opposing cutter 22 form a thread clamp. At the other end of the opposing cutter 22, a stop pin 26 protruding upward is formed. The stop pin 26 can be operatively connected to the operating plate 17 of the lever 14. The cutting device and the thread clamp form a cutting / tightening device 27.

At the end of the working sewing cycle, the cutting and tightening device 27 is closed in a known manner, whereby the upper thread is tightened above the sewn product moving frame 1 and is cut immediately thereafter.

In order to start the next sewing cycle,
The tightening device 27 is moved to the right by the drive rod 19 by approximately 5 mm according to FIG. At that time, the carrier 20 is
2 reaches the position shown by the broken line, and the carrier 20 contacts the guide surface 12 of the control plate 10 at this position. Due to this movement of the cutting / tightening device 27, the thread end FE on the stockpile side, which has been clamped and fixed, is placed in front of the needle 5 parallel to the feed direction V of the sewn product moving frame 1. Next, in order to form the left buttonhole overedging LR, the sewn product moving frame 1 is moved to the left side in FIG. During this moving movement, the guide surface 12 of the control plate 10 is moved to the carrier 20.
Is laterally pressed outward in the feeding direction V. As a result, the tightened thread end FE is pulled toward the center of the left buttonhole edge overhang LR. The amount of withdrawal of the yarn end FE to this side depends on the adjustment position of the control plate 10, that is, the farther the control plate 10 is from the carrying lever 13, the closer the yarn end FE is from the center line of the button hole. Pulled laterally outward.

Further, when the shoulder portion 16 of the lever 14 hits the carrier 20 while the sewn product moving frame 1 moves,
The lever 14 starts rotating counterclockwise. As a result of this pivoting movement, the operation plate 17 moves the stop pin 26 of the opposing cutter 22.
Then, the facing cutter 22 is rotated to the open position shown in FIG. While the cutting and tightening device 27 is opened, the end portion of the thread end FE is released and then completely sewn.

After the thread end FE is released, the stationary shoulder 8
Collides with the carrier 20, which causes the cutting
The tightening device 27 further rotates laterally outward. The pivotal position occupied by the cutting and tightening device 27 then forms the home position for the next thread tightening and cutting process which takes place at the end of this sewing cycle.

[0019]

By providing the respective cams for the lateral movement and the opening movement of the cutting / tightening device,
Furthermore, by means of these cams being at least partially positionable relative to each other, the functions of lateral movement and opening can easily be changed relative to one another during the adjustment process, whereby cutting and tightening is possible. The lateral movement of the device and the time of opening can be coordinated with each other so that the thread ends can be completely sewn up whether the buttonhole edge is narrow or wide. In this way, various factors which influence the sewing result can be eliminated, such as, for example, dimensional deviations of the individual parts of the device, support play, material-specific properties of the sewing thread.

[Brief description of drawings]

FIG. 1 is a side view of a sewn product moving frame and a thread cutting / tightening device.

FIG. 2 is a plan view of the sewn product moving frame and the thread cutting / tightening device, showing the position of the thread cutting / tightening device after cutting and tightening the upper thread by a solid line and before starting the next sewing cycle. It is the top view which showed the position with the broken line.

FIG. 3 is a plan view corresponding to FIG. 2, showing the thread cutting / tightening device immediately after opening.

FIG. 4 is a plan view of a button hole in which a needle thread end is sewn.

[Explanation of symbols]

 1 Sewn product moving frame 3 Carrying lever 6 Square member 8 Shoulder part 10 Control plate 12 Guide surface 13 Cam 14 Lever 15 Cam 18 Cam mechanism 27 Thread cutting / tightening device

Claims (2)

[Claims] 1. A sewn product moving frame that can move forward and backward together with a holding part, a needle bar that carries a needle that guides a thread, and oscillates laterally with respect to the feed direction of the sewn product moving frame, and an upper part at the end of a sewing cycle. It has a thread cutting / tightening device that cuts the thread and brings the thread end on the storage side to the front of the needle to enable sewing for the start of the next sewing cycle. A cam that is arranged on a carrier that is movable in the lateral direction and parallel to the frame feed direction, and that arranges the lateral movement and the opening movement of the thread cutting / tightening device in the holding portion of the sewn product moving frame. In a buttonhole sewing machine which is controllable by a mechanism, a cam mechanism (18) is provided for functionally dividing the lateral movement and the opening movement of the thread cutting / tightening device (27) to control these two movements. But each specific cam (13, 1
5) A buttonhole sewing machine, characterized in that it has at least part of the cams (13, 15) adjustable relative to each other. 2. A lever (1) cooperating with a retaining pin (26) on the holding part (3, 6) of the sewn product moving frame (1).
4) is supported, and the lever (14) moves one cam (1
5) having diagonal shoulders (16) forming
Another cam (13) is relatively movable with respect to the obliquely extending stationary shoulder (8) of the holding part (3, 6) and the holding part (3, 6), and an obliquely extending guide surface ( Formed with a control plate (10) with a guide surface (12)
The buttonhole sewing machine according to claim 1, characterized in that the stationary shoulder (8) is covered at a ratio according to the adjusted position of the control plate (10).