Thread control device of chain stitch sewing machine

Abstract

A yarn controlling device of chain stitch sewing machine is provided to remove bound and adhered looper thread because an amount of the looper thread bound and adhered to a shaft part is very small and to control a tension of the looper thread. A yarn controlling device of chain stitch sewing machine comprises a lower axis, a looper, two threads passing parts(12), a thread controlling cam(14) and a yarn guide member(15). The lower axis is rotated by rotation of a motor in the sewing machine. The looper is shaked and operated by the rotation of the lower axis. The thread controlling cam and the yarn guide member are arranged between the two threads passing parts. The yarn guide member contains a long aperture part for moving the looper thread along a fixed direction. The yarn controlling device of chain stitch sewing machine gives a tension according to change of a diameter of the two threads passing parts to the looper thread. The yarn guide member comprises the yarn controlling device.

Description

technical field [0001] The invention relates to a thread control device for a chain stitch sewing machine which controls the tension of the looping thread. Background technique [0002] Sewing machine with a looper that swings below the needle plate for overcasting or double chain stitching, sewing is performed by repeating the action of causing the looper to catch the thread of the upper thread inserted into the needle loop and let the needle catch the loop of the looping thread inserted into the looper. [0003] At this time, a sewing machine having a thread control device 110 as a thread control device for keeping the tension of the looping thread constant is widely used, such as Figure 13 As shown in (a), the wire control device 110 has: two threading parts 111, 112, which are used as the path of the looping wire L1; The looping wire L1 sliding contact between the threading parts; and the wire guide member 115, which is arranged between the two wire control cams, and i...

AI Technical Summary

Problems solved by technology

The removal of the looped thread L1 wound on the shaft 102a is very complicated and takes a lot of time, which brings a great burden to the operator and significantly reduces the efficiency of the sewing operation.

In addition, at the time of this removal, when cutting the looping wire L1 wound on the shaft portion 102a with a cutter or the like, there is a possibility that the cutter may come into contact with the surface of the wire control cams 113, 114 by mistake during this operation. Injury

In this case, in the sewing operation performed after the looping thread is removed, the looping thread L1 is likely to be caught by the damaged part, and the cutting and entanglement of the looping thread L1 may occur.

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