PURPOSE: To realize the easy and sure detection of needle thread and bobbin thread breakage by utilizing a mechanism containing an oscillating lever provided in the middle of a needle thread guide from a needle thread corn to a sewing machine, replacing the advancing state of the needle thread after the needle thread is periodically loosened with the movement of the oscillating lever, and measuring it.
CONSTITUTION: In an industrial sewing machine, a fixed shaft 3 is mounted on frames 11 on both ends, and oscillating levers manufactured from a wire and the like are mounted rotatably around the fixed shaft 3 by the number of needle threads. A light shielding plate 8 is mounted on the middle part of each oscillating lever 2, and the oscillating state of the oscillating lever 2 is detected by interrupting the optical paths of photoelectric sensors 9, 10 by the light shielding plate 8. After the needle thread is periodically loosened by a fixed quantity at the start of the period, the advancing state of the needle thread thereafter is replaced with the motion of the oscillating lever 2 and measured, a needle thread breakage is judged when the advancing state of the needle thread is O, and a bobbin thread breakage is judged when it is delayed by a fixed quantity or more, compared with the normal advancing state.
NISHIZAWA TSUTOMU
TANAKA YOSHINORI
NISHIZAWA TSUTOMU
TANAKA YOSHINORI