High precision thread trimming device and method for embroidery machine

Abstract

The invention discloses a high precision thread trimming device and a high precision thread trimming method for an embroidery machine. The device comprises a plastic cutter driving device and a thread trimming device, wherein the plastic cutter driving device is arranged at the upper side of a faller; the thread trimming device is arranged at the lower side of the faller; the plastic cutter driving device comprises a plastic cutter motor; a position sensor and an eccentric wheel are respectively arranged on the periphery of a drive shaft of the plastic cutter motor; the eccentric wheel is connected with a swing rod with a sliding chute at one end by a pin roller; a stationary shaft connected with a motor base is arranged in the middle of the swing rod; the other end of the swing rod is connected with a pull rod driving a plastic cutter by a connecting rod. The device has the beneficial effects that the exact position of the plastic cutter when going back is determined via the position sensor on the periphery of the drive shaft of the plastic cutter motor, thus achieving high precision control of the thread trimming length and avoiding technical defects caused by main shaft speed fluctuation.

Description

technical field [0001] The invention relates to a thread trimming device and method, in particular to a high-precision thread trimming embroidery machine thread trimming device and method. Background technique [0002] At present, for the embroidery machine industry, after completing one graphic unit of embroidery, it is necessary to trim the upper thread and lower thread under the cloth surface when starting to embroider another graphic unit. Due to the large number of embroidery units, frequent thread trimming is required, and the thread trimming remains The lower thread end is located under the cloth surface, and the length of the thread end is directly related to the quality of the embroidery and the cost of the upper thread. The existing thread trimming method is generally that one upper thread driven by the flower machine needle passes through the cloth surface to form two upper threads. These two upper threads wrap the bottom thread under the cloth surface through the...

AI Technical Summary

Problems solved by technology

The existing thread trimming method is generally that one upper thread driven by the flower machine needle passes through the cloth surface to form two upper threads. These two upper threads wrap the bottom thread under the cloth surface through the rotary hook. Scissors cut a strand of upper thread and lower thread, and the cut strand of upper thread and lower thread forms a thread end under the cloth surface. The scissors have no ability to control the length of the thread end, that is, the thread end will be long and short for a while. The main factor affecting the length of the thread head is the length of the thread trimming caused by the change in the time when the scissors start cutting the thread caused by the fluctuation of the speed of the spindle speed.

[0003] Of course, there are also mechanical structures such as hook knife, upper thread clamping, and thread hook in the existing thread trimming process, but these mechanical structures do not control the length of the thread trimming. The main function of the hook knife is to maintain the tension of the upper thread and to help Although the upper thread is pulled back and the upper thread clamp is used to fix the upper thread during thread trimming, the action time of the upper thread clamp is also controlled by the rotation of the main shaft. There is uncertainty. The thread is bifurcated into a loop. At present, there is also a method of trimming the thread when the fork forms a loop and breaks away from the hook. This leads to uncertainty in the length of the trimmed line

In addition, in the prior art, the hook knife motor and the swing bar of the hook knife are installed on the side of the crossbeam of the embroidery machine, which causes the swing direction of the swing bar to be in the vertical direction, while the pull bar connecting the hook knife is in the horizontal direction. The lack of movement is for the front and rear and up and down adjustment functions of the pull rod, that is, the lack of fine-tuning of the position of the hook knife or the length of the trimmer

How to solve the technical problems of uncertain thread trimming length and low precision has always been the research object of those skilled in the art

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