Sewing machine automatic trimming control device and method

Abstract

The invention provides a sewing machine automatic thread trimming control device and method, and belongs to the technical field of machines. The problem that thread residues obtained after thread trimming with an existing control device are prone to loosing and uneven in length is solved. The sewing machine automatic thread trimming control device comprises a controller, a counting / timing sensor, a thread trimming mechanism and an induced draft mechanism, a sewing thread number counting / timing module is arranged in the controller, and the controller further comprises a setting module; the controller subtracts the counting value SET from the action delay value TSET to obtain thread trimming start calculation value LCNT, and when the counting value CNT is larger than or equal to the induced draft start counting value NCNT, the controller controls the induced draft mechanism to start induced draft work; when the counting value CNT is larger than or equal to the induced draft close value MCNT, the controller controls the induced draft mechanism to close induced draft work; when the counting value CNT is larger than or equal to the thread trimming start calculation value LCNT, the controller controls the thread trimming mechanism to start thread trimming work. The sewing machine automatic thread trimming control device has the advantages that the thread residues do not loose and are uniform in length.

Description

technical field [0001] The invention belongs to the technical field of machinery, and relates to an automatic thread trimming control device and method for a sewing machine. Background technique [0002] The thread trimming action of the sewing machine is generally divided into front trimming and rear trimming. The front trimming is to cut off the braids at the front of the fabric, and the rear trimming is to cut off the braids at the rear edge of the fabric. At present, the front thread trimming action generally sends a signal to the electronic control through the front thread trimming sensor, and the electronic control controls the thread trimming mechanism to cut off the thread braids at the front of the cloth. [0003] For example, the published publication number is CN101532223A, which is named as a Chinese patent on an automatic braid cutting device for overlock sewing machine and working method. , wherein, the electromagnet driving device is connected with the sheari...

AI Technical Summary

Problems solved by technology

Although this technical solution realizes the thread trimming signal to the controller through the needle number counter to realize the automatic thread trimming function, there are still some problems: the main thread ends are easy to loose and unsightly

[0006] Although the suction structure is an existing technology, the prior art and the above-mentioned published patents do not precisely control the suction time, so the above-mentioned published patents have the situation of loosening the thread ends in the above-mentioned first point

At the same time, the above-mentioned published patent does not involve the driving sources of different thread trimming mechanisms. The controller sends the thread trimming control signal to the thread trimming mechanism, and the time between the thread trimmer on the thread trimming mechanism turning to the thread braid for cutting is different. , so different driving sources drive the thread cutter to stay at the sewing table for different lengths of time, and the situation mentioned in the second point above will also occur

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