| 摘要 |
A frame (10) of a needle bar mechanism is mounted in a sewing machine arm and supports the swingable needle bar holder (13) by which the zigzag motion of the needle is enabled. A stepping motor (24) is mounted in the frame and connected by means of a link (26) from the shaft of the motor to the needle bar holder. The motor is controlled by stich codes supplied by amplification circuits and automatic control devices. Owing to the design of the link, the driving arrangement can be provided with calibration and an elastic engagement between the motor shaft and the needle bar holder. The transfer distance through only one link is short so the friction loss is small which in combination with a small keeping torque of the needle bar will restrict the dimension of the stepping motor. |
