| 摘要 |
This disclosure relates to a control mechanism for a blindstitch tacker wherein a single control device is provided for progressively moving a node former and work clamp of a sewing machine into clamping engagement with a workpiece, and further movement of the control mechanism results in the initiation of the stitching operation. The control mechanism includes a multiple lever arm bell crank with different ones of the lever arms thereof actuating different mechanisms of the sewing machine. The control mechanism also includes a cam and cam follower for actuating the node former and work clamp with there being an overcenter position wherein further movement of the bell crank does not result in further movement of the node former and work clamp. When the bell crank has moved to this position, a spring retains the bell crank in its operative position without assistance by the operator. The control mechanism is automatically returned to its inoperative position upon the termination of a predetermined sewing cycle.
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