Active thread supply device, sewing machine and active thread supply method

Abstract

The invention provides an active thread supply device which comprises a fixed seat, two thread supply wheels rotatably mounted on the fixed seat, a thread clamping gap formed between the outer peripheral surfaces of the two thread supply wheels and a driving source mounted on the fixed seat, and the driving source is connected with the thread supply wheels and drives the thread supply wheels to rotate. The active thread supply device can convey a sewing thread to a machine needle when the sewing machine needs the sewing thread, the thread supply amount of the sewing thread is larger than the needed thread amount, then the sewing thread can still be in a loose state when a part in the sewing machine pulls the sewing thread, the thread tension of the sewing thread is low, the sewing thread easily slides through the surface of the part in the sewing machine in a low-thread tension state instead of being forcibly dragged through the surface of the part in the sewing machine in the prior art, so that the sewing thread is prevented from being damaged and even broken; and the requirements on the surface smoothness and the mounting precision of the thread passing piece in direct contact with the sewing thread in the sewing machine are reduced, and the manufacturing cost of the sewing machine is finally reduced.

Description

technical field [0001] The invention relates to an active wire supply device. [0002] The present invention also relates to a sewing machine equipped with the above-mentioned active thread supply device. [0003] The present invention also relates to an active thread supply method for the above sewing machine. Background technique [0004] A thread clamp and a thread take-up mechanism are usually installed on the casing of the sewing machine, and the upper thread passes through the thread clamp and the thread take-up mechanism and then passes into the machine needle. The structure of the thread clamp can be used in a thread clamping device disclosed in the Chinese Utility Model Patent Application No. 201920411036.7, or refer to a thread clamping device of a sewing machine disclosed in the Chinese Invention Patent Application No. 201810436759.2. Existing sewing machines control the stitches by adjusting the tension of the thread tensioner, and control the thread supply len...

AI Technical Summary

Problems solved by technology

[0010]A certain degree of twisting, untwisting, and unraveling of the suture, causing the loop to become unstable and deviate forward or backward; When the mechanism hooks the thread, the silk light or the thick thread loop will easily catch only a part of the suture, resulting in thread splitting; the thin cotton thread or thin polyester thread loop will be distorted and deformed, resulting in skipping stitches and thread breakage; and the thread take-up lever When taking up the thread, the twisted suture will form a butterfly-shaped floating point after twisting; hard knots will also cause floating points in the stitches, and the greater probability is that the thread will be broken directly

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