Method used for detecting remaining quantity of cop latch base lines of sewing machine

Abstract

The invention provides a method used for detecting the remaining quantity of cop latch base lines of a sewing machine. Reflective paper is attached to the outer surface of a cop latch disc of the sewing machine. The reflective paper is in a ring mode provided with black strips and white strips, and the black strips and the white strips alternately arranged and evenly distributed. A sensor is right opposite to the reflective paper and is in communication with an electronic control unit of the sewing machine to detect the total number Nx of the black strips where the reflective paper rotates when a machine needle of the sewing machine moves a preset number x of threads every time, and a signal is generated and transmitted to the electronic control unit. The method includes the steps that the electronic control unit receives the signal related to the needle distance B, the fabric thickness H, the cop latch bottom diameter d, the total number N of the black strips of the reflective paper and the total number Nx of the black strips where the reflective paper rotates when the machine needle of the sewing machine moves the preset number x of threads every time; secondly, by means of the electronic control unit, the cop latch base line remaining line thickness h of the sewing machine is calculated through the formula (please see the formula in the specification) shown in the specification. By means of the method, the remaining line quantity of a cop latch can be precisely detected.

Description

technical field [0001] The invention relates to the technical field of sewing, in particular to a method for detecting the remaining thread amount of bobbin bobbins of a sewing machine. Background technique [0002] Due to the limitation of sewing machine space and mechanism principle, bobbin bottom thread is generally shorter and difficult to observe. Since the amount of bobbin thread cannot be increased during sewing operation, frequent bobbin replacement is required. Once there is a missing line operation, defective products will be produced. Therefore, it is necessary to detect the remaining thread amount of the bobbin bottom thread. [0003] There are two main methods for automatic detection of bobbin bottom thread remaining thread amount at present: [0004] (1) Use the sensor to detect whether the photosensitive member on the bobbin disc rotates; if the photosensitive member does not rotate, it is judged that the bobbin thread is exhausted; however, the detection t...

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Problems solved by technology

[0006] (2) Use the sensor to detect whether the photosensitive part on the bobbin shaft is exposed; if the photosensitive part is exposed, it means that the bottom thread is about to run out; the bottom thread margin detected by this method is relatively short (about 1 meter); in some disposable In the case of long-distance sewing (such as large-scale template machines), when it is detected that the bottom thread is about to run out, the sewing machine may have started a long-distance sewing, and stopping in the middle of sewing will also cause poor stitch quality

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