Wire cutting device for swwing machine

Abstract

Thread separation device of the invention comprises: a mobile knife 2 moving between a ready position and a thread catch position back and forth; a being certain thing knife 4 moving between a ready position and a working position back and forth and separating a thread in cooperating with the mobile measurer 2 in the working position, a front stopper 7 holding the being certain knife 4 in the ready position ; a rear stopper 8 holding the being certain knife 4 in the working position; a thread retaining spring 5, linking up the mobile knife 2 to the side of the being certain measurer 4; a measurer pressure adjustment plate 6, linking up the mobile knife 2 to the side of the being certain measurer 4 in a larger force for linking up than that of the thread retaining spring 5; a measurer basis 1 for holding each of these members; and thread separation electromagnets 10 as a power source for driving the mobile knife 2. The measurer pressure adjustment plate 6 has a pattern to link up the mobile knife 2 to the side of the being certain measurer 4 in a working position without linking up in a ready position.

Description

technical field [0001] The present invention relates to a thread cutting device of a sewing machine having a movable knife having a catch portion for catching a sewing thread and a fixed knife cutting the sewing thread by slidingly contacting the movable knife. Background technique [0002] Conventionally, there is known a thread cutting device for a sewing machine: it is provided in the bottom plate of the sewing machine, and has a movable cutter that moves forward and backward near the needle drop position after sewing and a fixed cutter that engages with the movable cutter (for example, Refer to Patent Document 1). [0003] The movable cutter has a catching part that catches the upper thread and the lower thread when moving backward after moving forward near the needle drop position. And, while drawing the upper thread and the lower thread caught by the catcher, these sewing threads are cut by cooperating with the fixed cutter. [0004] In addition, the fixed knife adop...

AI Technical Summary

Problems solved by technology

[0009] However, when the pressing force is set high, since the frictional force between the two is increased, a large driving force is required when the movable cutter moves forward and backward, especially when it is started.

Therefore, when sewing a thick thread, it is necessary to increase the size of the drive unit of the thread cutting device, which is not an ideal structure when the size and cost of the thread cutting device are reduced.

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