Thread-loosening device of sewing machine

Abstract

The invention relates to a thread-loosening device of a sewing machine, which consists of a base plate, at least two thread-pressing discs, a rotating piece, a pneumatic cylinder and a resetting unit, wherein each thread-pressing disc comprises a locating post, a regulating unit, a press drawing piece, a carrying piece, an elastic unit and a pin body; the rotating piece is pivoted with the base plate and is provided with a leaning surface which is provided with at least one groove and at least one sliding groove; and the pneumatic cylinder is used for pushing the rotating piece to rotate, thegroove and the sliding groove are at least allowed to respectively rotate away from the positions corresponding to the pin bodies, and the pin bodies have displacement when leaning against the leaning surface. Due to the structure, the thread-loosening device of the sewing machine is used for providing a needle tread which is respectively wound between the press drawing pieces and the carrying pieces of the two thread-pressing discs; the pneumatic cylinder is used for pushing the rotating piece to rotate, so that the pin bodies have displacement when leaning against the leaning surface; and the groove and the sliding groove are sequentially moved away from the pin bodies, so that the press drawing force of the press drawing pieces can be released, and the tension for releasing, maintaining and regulating the needle thread can be controlled.

Description

technical field [0001] The invention relates to a thread loosening device of a sewing machine, in particular to a thread loosening device of a sewing machine which utilizes air pressure to control a pressure plate to control releasing, maintaining or changing the tension of a needle thread. Background technique [0002] At present, the industry uses combined feeding sewing machines for sewing leather goods and other sewing operations. When sewing materials with different thicknesses, or sewing different parts of finished materials, or encountering different thicknesses due to the increase in the number of layers of laminated leather , It is necessary to alternately control the needle and thread to adjust different tensions to achieve the ideal seam quality. [0003] In order to achieve this purpose, the existing sewing machine elastic thread device is as the Chinese invention patent application whose publication number is CN1600932 and the name is "sewing machine thread tens...

AI Technical Summary

Problems solved by technology

[0005] 1. Because the above-mentioned existing structure uses two electromagnets to respectively push two sets of tensioners with different spring pressures, or use one electromagnet to control the change of its output thrust with the current size to control the release or maintenance of the tensioner The tightness must be accompanied by a complex circuit system, so it is bulky and occupies a large space, which is not conducive to the overall assembly and matching

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