| 摘要 |
In a sewing machine a thread 20 moves through a check spring 30, through a takeup arm 32, and to a needle 15. During normal operation, a proximity detector 55 detects the movement of a flag 50 attached to a loop 36 of the check spring during each movement of the takeup arm 32. The proximity detector is supported in a position adjacent the path of movement of the flag. When the thread breaks at the needle, tension is no longer applied to the thread by takeuparm 32, so that check spring 36 and its flag 50 no longer move in front of the detector 55, causing a control circuit to deactivate the sewing machine motor.
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