GAS-CONVEYED THREADING DEVICE FOR SEWING MACHINE

摘要

When performing the threading to the looper by one-touch operation, the abnormal changeover to the stitch forming state of the looper threading/stitch forming changeover mechanism during the gas supply operation of the gas supply pump is prohibited. The device comprises: a clutch (60) for transmitting the power from the sewing machine motor (M) to the drive shaft (5) that drives the stitch forming device (30) including the looper (7, 8, 9) at the time of the stitch formation or to the gas supply pump (41) at the time of the looper threading respectively; a looper threading/stitch forming changeover mechanism (90) for changing over the clutch so that the transmission of the power to the stitch forming device is interrupted and the power is transmitted to the gas supply pump at the time of the looper threading and the power is transmitted to the stitch forming device and the transmission of the power to the gas supply pump is interrupted at the time of the stitch formation; and a changeover prohibition mechanism (160) for prohibiting the abnormal changeover to the stitch forming state of the looper threading/stitch forming changeover mechanism during the gas supply operation of the gas supply pump.