FORMING FIRST STITCH IN TWO-THREAD CHAIN STITCH OR COVERING CHAIN STITCH SEWING MACHINE

摘要

PURPOSE:To form a predetermined two-thread chain stitch or a covering chain stitch securely and achieve two-thread chain stitch sewing or covering chain stitch sewing of a good appearance for the first stitch of sewing by rotating a looper in the inverse direction to the normal to move till it reaches to the end of the rotary motion, and performing rotary motion in the normal direction from the timing. CONSTITUTION:When a looper 4 reaches the left end of a circular rotary motion passage 6, sewing needles 6, 7 protrudes up from a cloth 9 toward an upper dead point, when a looper thread 3 gets entangled with needle thread loops 11, 11. The sewing needles 6, 7 then move down from the upper dead point in the direction of an arrow (a) to penetrate the cloth 9 again. Interlocked with the down motion, the looper 4 rotates in the normal direction to move from the left end toward the right end as shown by an arrow (b), a looper thread loop 12 formed between a thread end 5 and the looper 4 is taken by the sewing needles 6, 7, thereby a predetermined two-thread chain stitch is formed for the first stitch of sewing.