| 摘要 |
A self-adjusting wrap spring clutch has a spring overlying driving and driven arbors and in engagement with each. One end of the spring is loosely connected to a control collar, which surrounds the spring and at least a portion of each of the arbors, while its other end is connected to the driven arbor. The control collar is held against rotation by a spring biased pawl engaging one of a plurality of preferably equiangularly spaced teeth on its circumference. When a solenoid is energized, the pawl is withdrawn from the tooth on the control collar and the spring tightens on the driving arbor to transmit torque to the driven arbor from the driving arbor. The pawl rides on a cam surface on a gear hub, which rotates whenever the driven arbor rotates, until the pawl falls into an opening or low dwell in the cam surface so that the pawl can engage one of the teeth on the control collar. Since the solenoid is deenergized shortly after energization, the pawl's engagement with the tooth stops rotation of the control collar to stop rotation of the driven arbor through holding the end of the spring so that it can no longer transmit torque to the driven arbor from the driving arbor.
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