Thread tension device of sewing machine

Abstract

A thread passing unit for sewing machine has a path length regulator for feeding thread, which features that the path length formed by fixed thread path, movable thread path and the thread path on needle rod is set up to 1 for the upper dead point of needle rod and more than 1 for the lower dead point. As a result, when the needle rod is raised up or lowered down, the thread is in relaxation state to ensure sewing quality.

Description

technical field [0001] The present invention mainly relates to a thread passing device applicable to a multi-needle interlock sewing machine, in particular to such a thread passing device of a sewing machine, which consists of a needle bar thread path installed on the upper end of a needle bar that can swing back and forth in an up and down direction; The fixed thread path arranged next to the suture tension regulator; and the swing mechanism that is arranged between the fixed thread path and the needle bar thread path and synchronously interlocks with the up and down reciprocating motion of the needle bar in the up and down direction A movable thread passage on the end of the thread handle forms the thread feed path from the thread tension regulator to the machine needle. Background technique [0002] Fig. 7 is a perspective view showing the main structure of a thread passing device commonly used in a multi-needle interlock sewing machine. The thread passing device in the ...

AI Technical Summary

Problems solved by technology

If the above-mentioned traditional thread passing device is used when sewing this kind of gray cloth, the stitches formed by the thread and the bent thread will be wound on the claws of the needle plate and it is difficult to escape from the claws, which will hinder the feeding of the cloth. Easy to cause poor sewing

Also, even if the stitches come out of the claws, when the needle reaches the bottom dead center after passing through the gray cloth, the thread in a tense state will press the gray cloth downward, and after passing through the gray cloth from the bottom dead point, it will rise to the upper dead point. At the same time, there will be a phenomenon that the gray cloth is pulled up by the thread and the bent thread together, so that the sewing part of the gray cloth is too tight, and it is easy to make the sewing part of the gray cloth form a semicircular cone-shaped bulge, resulting in a decrease in the quality of the sewn product

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