Sewing machine

Abstract

A seaming machine (10) comprises a cutter (4) for cutting suture line, a cloth press (20) for lifting compress foot (21), a pulse motor (13) driving the two devices, a ROM93 storing multiple rotation speed data (93c) defining the rotation speed of the pulse motor when the cutter cuts suture line, a rotation speed selector (as CPU91) for selecting the rotation speed data generating the drive torque capable of cutting suture line at least from the ROM, according to the suture line thickness input by a controller (98), relative to the drive voltage of a conchoids (81) driving a yarn change mechanism (80), and a drive controller (as CPU91) for controlling the rotary drive of the pulse motor according to the selected rotation speed data. The invention can optimize the rotation speed of the drive motor when cuts suture line to reduce rotation period.

Description

technical field [0001] The present invention relates to a sewing machine with a driving mechanism for sewing threads and a cloth pressing mechanism for raising and lowering a pressing foot. Background technique [0002] Conventionally, a known sewing machine has a drive mechanism for moving a movable blade to cut a suture, and a cloth presser mechanism for raising and lowering a presser foot, and these mechanisms are operated by a drive motor. Furthermore, in recent known sewing machines, both mechanisms are operated by controlling the rotation of a single drive motor. (For example, refer to Patent Document 1) [0003] In these sewing machines, for example, after sewing, based on the rotational drive of the above-mentioned drive motor, after the sewing thread is cut by the cutting mechanism, the presser foot of the cloth pressing mechanism is raised, and then the sewing machine is restarted. Lower the presser foot. Therefore, from the viewpoint of shortening the operating...

AI Technical Summary

Problems solved by technology

Therefore, in order to shorten the operation cycle of the sewing machine, it is preferable to increase the rotation speed of the pulse motor. However, if the rotation speed is increased, when using thick sutures or sutures made of hard materials, the drive of the pulse motor may be insufficient and the movement may occur. When the blade cannot move reliably and the suture cannot be cut properly

[0006] Also, normally, the presser foot is given a downward elastic force, and the pulse motor is driven to resist the elastic force to raise it. However, the downward elastic pressing force may be generated depending on the thickness of the fabric to be sewn or the type of fabric. Therefore, when the presser foot is raised and lowered, if the pressing force is increased, the torque when the presser foot is raised will be increased by resisting the pressing force and driven by the pulse motor

Therefore, if the pulse motor is driven at an excessively high speed, the driving torque may be insufficient, and the lifting operation of the presser foot may not be properly performed.

[0007] In addition, in solving the above-mentioned problems, it is considered to use a high-output drive motor, but at this time, there are problems of increasing the size of the drive motor and increasing the cost, and it cannot be realized.

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