| 摘要 |
PURPOSE: To improve sewing efficiency while surely preventing an upper thread from being dropped. CONSTITUTION: It is designated by an upper thread drop prevention setting means 12 how many stitches make upper thread drop prevention control effective after the start of sewing. When a stitch count value due to a sewing machine needle position detector 9 exceeds the designated number of stitches, a motor control means 8 stops the transmitting of a motor current limit value signal and relaxes motor current limitation to a motor driver 19 in the middle. Thus, when the upper thread get tangled around fabric even during the motor driving current limitation for upper thread drop prevention, sewing speed is rapidly accelerated. |
