A method for controlling the stability of the thread end length in the needle of a sewing machine

Abstract

The invention provides a method for controlling the stability of the thread length in a needle of a sewing machine, comprising the following steps: setting a thread presser, a driving source, and a presser foot lifting mechanism connected between the driving source and the presser foot in the sewing machine in the sewing machine; When the needle moves down at the start of sewing, the thread press acts on the section of the stitching thread that is inserted between the thread take-up lever and the needle in the sewing machine, and increases the thread tension of this section of stitching thread. The presser foot lifter mechanism lifts the presser foot up by a preset height. In the present application, when the needle moves down at the start of sewing, the thread tension of the stitching thread between the thread take-up lever and the machine needle is increased by the thread presser, which can shorten the length of the stitching thread remaining on the side of the machine needle and avoid the bird's nest phenomenon. , to ensure beautiful stitches; at the same time, in the above process, the driving source lifts the presser foot slightly through the presser foot lifting mechanism, so as to avoid the remaining stitching thread on the needle side being pressed by the presser foot, so as to avoid the stitching caused by the presser. The phenomenon of being pulled and broken due to the combined action of the presser foot.

Description

technical field [0001] The invention relates to the field of sewing machines, in particular to a method for controlling the stability of the length of a thread in a needle of a sewing machine. Background technique [0002] At present, all sewing machines are equipped with automatic thread trimming mechanisms, such as an automatic thread trimming mechanism for sewing machines disclosed in Chinese invention patent application No. 201710215982.X, which is used for automatic thread trimming at the end of sewing, and after thread trimming is completed A length of stitching thread remains on the sewing material, and a length of stitching thread remains on the side of the needle. After the actual use of the sewing machine, there are the following problems: the length of the remaining stitching thread on one side of the needle is very unstable, and it is very easy to cause problems such as the thread end of this section of stitching being pulled off, shortening in length, and comple...

AI Technical Summary

Problems solved by technology

After the sewing machine is actually used, there are the following problems: the length of the remaining suture end on the needle side is very unstable, and it is very easy to have problems such as the end of the suture being pulled off, shortened in length, and completely protruded from the needle hole of the needle. , thus affecting the formation of stitches at the beginning of sewing

Therefore, after the upper thread is cut off by the engagement of the movable knife and the fixed knife, and then the movable knife and the fixed knife are separated and reset, the thread take-up lever continues to move upwards to take up the thread. A section of upper thread passes through multiple thread passers and thread grippers, and is in a state of tension or low tension, but the section of upper thread between the thread take-up lever and the needle is in a state of no tension, and the thread take-up action is performed with the thread take-up lever , the part of the upper thread between the thread take-up lever and the needle will be taken away, which will cause the length of the thread remaining on the needle side after thread trimming to be unstable, and it is very easy to cause thread trimming flying thread and remaining thread on the needle The thread end in the middle becomes shorter, the thread end comes out completely from the needle hole of the machine needle, etc., which will affect the formation of stitches at the next sewing start

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