When the top sleeve is reversing-rotated, the contact piece leaves the inclining surface, the upright rod is bounced back upwards, and the motor circuit is cut off.
反向转动顶套时，触片离开斜面，竖杆向上弹回，马达电路被断开。
The utility model can be fixed in any position of an upright rod according to different operating requirements. The utility model has the advantages of convenient use, firm fixation, etc.
本实用新型可根据各种不同使用要求在立杆上任何位置加以固定，具有使用方便，固定牢固等优点。
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