Method for detecting baseline margin of sewing machine

Abstract

The invention provides a method for detecting a baseline margin of a sewing machine. The method successively comprises the steps that a residual baseline wound on a wrapping pillar drives a bobbin to rotate, and the bobbin drives multiple sensed parts on a flange to rotate synchronously; a sensor senses the sensed part exposed from a through hole of a bobbin sleeve and then outputs a pulse signal, wherein the pulse signal is formed by high levels and low levels which are distributed at intervals; an electric control module of the sewing machine receives the pulse signal from the sensor and detects a level frequency of the pulse signal; when the level frequency of the pulse signal increases, the electric control module can determine that the baseline margin on the wrapping pillar is enough and can control a main motor of the sewing machine to continue rotating; and when the level frequency of the pulse signal decreases, the electric control module determines that the baseline margin on the wrapping pillar is insufficient and controls the main motor of the sewing machine to stop rotation. According to the application, whether the baseline margin on the bobbin is enough is determined according to rotation speed changes of the bobbin. The method has the advantages of very high detection accuracy and high reliability.

Description

technical field [0001] The invention relates to a sewing machine, in particular to a method for detecting the remaining amount of the bottom thread of the sewing machine. Background technique [0002] Lockstitch is a sewing machine that connects the upper thread and the lower thread in series on the sewing material according to certain rules, and forms a firm and beautiful stitch. It is often used to sew two pieces of sewing material to each other. like figure 1 As shown, the formation process of the lock stitch includes the following six stages: stabbing material stage, thread loop formation stage, thread loop expansion stage, loop stage, thread loop contraction stage, and seam forming stage, figure 1 a to figure 1 e are the loop forming stage, the loop expanding stage, the loop stage, the loop shrinking stage and the seaming stage respectively; wherein, in the seaming stage, the thread take-up takes up the thread, so that the thread loop formed by the upper thread and th...

AI Technical Summary

Problems solved by technology

However, when the sewing machine is running at high speed, the machine will generate a large vibration, which will be transmitted to the bobbin, so that the bobbin continues to rotate under the vibration of the machine, so that the sensor receiver still outputs pulse signals until the bottom thread is completely is used up, at this time, a section of void without stitches will be formed on the sewing material, that is to say, the above-mentioned sewing machine bobbin thread amount detection device and detection method cannot detect in real time and in time when the sewing machine is running at a high speed. Is the bottom line running out

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