Lower thread cutter of sewing machine

Abstract

The invention relates to a lower line shearing device for the sewing machine, comprising a fixing board, a lower mounting board, a sliding guidance piece and a linkage arm. The fixing board is fixed onto the platform of the sewing machine, having an oblique guidance slot and a first guidance piece for assembly and accommodation of a second guidance piece and a guidance hole of the lower mounting board. The mounting board is equipped with a fixed cutting knife group and a clip group on the upper and the lower surface respectively, a third guidance piece is disposed on the lower mounting board,and correspondingly threaded on a long sliding slot on a sliding guidance sheet. The sliding guidance sheet is equipped with a wire hook rod, whose front end is clamped and limited by the fixed cutting knife group. The sliding guidance sheet is further equipped with a long hole for correspondingly accommodation of the fourth guidance piece on the linkage arm, while the linkage arm is hinged to the fixing board on the central portion thereof. Consequently, the lower line shearing group is capable of reducing the distance between the fixed cutting knife group and the suture when finishing the line shearing operation, so that the left tail on the cloth is relatively shorter after the line shearing operation completion.

Description

technical field [0001] The invention relates to a lower thread cutter of a sewing machine. Background technique [0002] The lower thread cutter of the existing sewing machine has a fixing plate, which is fixed with the bed of the sewing machine, and is used for assembly and positioning of the thread cutting group. The thread cutting group has a mounting plate, and the mounting plate is fixed on the fixing plate. And a sliding guide is set on the mounting plate, the front end of the sliding guide is provided with a movable cutter, and the mounting plate, sliding guide and movable cutter are linked with a linked swing arm, and the linked swing arm Swings driven by a solenoid valve. In this way, when the solenoid valve drives the linked swing arm to move, the linked swing arm will drive the mounting plate, the slide guide and the movable cutter to perform deflecting, moving, thread hooking and thread cutting actions. [0003] However, when this existing lower thread cutter s...

AI Technical Summary

Problems solved by technology

[0003] However, when this existing lower thread cutter structure is performing thread trimming operations, its interlocking swing arm only first drives the entire lower mounting plate and the sliding guide to perform angular deflection actions. When the interlocking swing arm continues to When it is linked, the sliding guide piece will be fully pushed out, and the thread hooking lever on it will protrude out to carry out the thread hooking action. Because the fixed cutter group and clip group of the lower thread cutter are fixed On the lower mounting plate, and the lower mounting plate only swings at a small angle during the whole thread cutting operation, so the stroke of the thread hooking lever’s entire protrusion and thread hooking is longer, that is, to fix the cutter group to the suture position The longer the distance, the longer the length of the tails left on the fabric after cutting the stitches. This not only causes waste of stitches, but also requires manual cutting of the tails in order to refine the product. Unnecessarily increase the cost of sewing processing

[0004] Please refer to China Taiwan Patent No. 84205229 and No. 86218218, both of which are new patents related to the thread cutting device invented by the inventor, and the above two patents all have the aforementioned thread left on the cloth after cutting the suture Disadvantages associated with relatively long tail length

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