Buttonhole serging machine

Abstract

The invention provides a buttonhole serging machine which can always set optimal needle swing amplitude correction value according to optionally set sewing speed, can go on sewing when fault happens in the sewing process and can form buttonhole hemming with uniform hemming. A storage unit thereof stores the needle swing amplitude correction value set correspondingly to the hemming width and sewing speed; a control unit corrects drive control data and generates correction control data according to the needle swing amplitude correction value of needle dropping coordinate data used for obtainingexpected hemming width and calculated by the storage unit from the sewing speed adjusted by a speed adjusting unit, so as to make needle swing amplitude be the amplitude added with the needle swing amplitude correction value on the expected hemming width. Drives of a cloth feeding drive mechanism, a needle swing drive mechanism and a needle rod upper and lower drive mechanism are controlled according to the correction control data.

Description

technical field [0001] The present invention relates to a buttonhole overlock sewing machine for overlocking the periphery of a buttonhole by controlling the needle swing width of a needle bar. Background technique [0002] Such as Figure 4 As shown in , on a buttonhole overlock sewing machine, buttonhole overlock sewing is performed with a fixed overlock width set around the periphery of the buttonhole. The buttonhole overlock sewing machine is equipped with a main motor that drives the needle bar up and down drive mechanism, and a needle swing motor that drives the needle swing drive mechanism, and performs sewing while moving the needle bar up and down while swinging at a constant needle swing width . [0003] In addition, the rotational speed of the main motor, that is, the sewing speed, is set to an arbitrary speed within the maximum speed by adjusting the speed adjustment knob with the set value set by the operation panel as the maximum speed. [0004] However, when...

AI Technical Summary

Problems solved by technology

[0004] However, when sewing buttonhole overlocks set to a fixed overlock width, if Figure 4 As shown in (A), in the case of sewing at a low speed, the overlock width is as set, but as Figure 4 As shown in (B), in the case of sewing at high speed, it becomes a stitch narrower than the set overlock width

The reason is that the needle swing of the needle bar is at high speed when driven at high speed, so the inertia of the needle swing increases and stable needle drop cannot be obtained. Stitches are formed under high tension, so the fabric will move closer to the center of the overlock width

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