Thread-tension adjusting device of sewing machine

Abstract

A thread tension regulating device of a sewing machine is controlled by a device (8) on a circulating sewing machine body (2). And the cycle sewing machine body (2) is provided with an EEPROM (60) for storing and maintaining the inherent correction value ΔI of the sewing machine body. The control device (8) calculates the level I corresponding to the thread tension value set by the operation panel (5) and reads the correction value ΔI from the EEPROM (60). Then the control device (8) makes the driving current of the level (I+ΔI) obtained by adding the correction value ΔI to the level I flow through the solenoid (15) for upper thread. Since the correction value ΔI unique to the sewing machine body is stored in the EEPROM (60) of the sewing machine body (2), a driving current of level (I+ΔI) flows regardless of the combination of the sewing machine body and the control device. It makes the seam feel the same on each sewing machine and realizes the stability and repeatability of improving the sewing quality.

Description

technical field [0001] The invention relates to a thread tension adjusting device of a sewing machine which can change the thread tension by electric control. Background technique [0002] In the past, the sewing machine equipped with a thread tension adjusting device that can change the thread tension by electrical control, for example, as disclosed in the Japanese Patent Application Publication No. 2000-202183, is known to use a solenoid to act on the thread tensioner. Thrust line tension adjustment device. As the solenoid, a solenoid having a thrust acting on the thread gripper from the movable part of the solenoid and a specific stroke interval that does not follow the stroke of the movable part is used. At this time, if the current flowing into the solenoid If it is certain, the thread tension that the thread clamp acts on the thread varies according to the thickness of the thread. Therefore, if you control the current flowing into the solenoid, you can theoretically ...

AI Technical Summary

Problems solved by technology

[0003] However, in the above-mentioned thread tension adjusting devices, the surface roughness of the thread tensioner and the thread friction surface of each thread tension adjusting device is different due to the deviation of the parts in the manufacturing stage, or the surface finish of each thread tension adjusting device is different. The characteristics of the solenoids on the adjustment devices are different, or the installation condition of the tensioner on each thread tension adjustment device is different, so even if the current levels flowing through the solenoids of each thread tension adjustment device are equal, the The tension actually acting on the thread sometimes varies depending on the thread tension adjustment device

[0004] On the other hand, when the thread tension of the same value is set from the operation panel of each sewing machine, the calculation of converting the thread tension into current by the control device of each sewing machine is the same, and since the same current flows through the solenoid , the tension applied to the thread by each thread tension adjustment device is also different, so there is a problem of non-commutability of setting data between various sewing machines

That is, even if the same value of thread tension is set from the operation panel, and the control device flows a current corresponding to the set value to the solenoid, the tension generated by the thread tension adjusting device on the thread is different for each sewing machine. , and there is a problem that the touch feeling of the stitches formed on each sewing machine is also different

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