| 摘要 |
An anti-reversal device is provided whereby a wheel and shaft are free to rotate in one sense (B) relative to a stationary member but are prevented from counter-rotating in the sense (C) by engagement of load-bearing pins between teeth of the respective members. The pins are positively driven to the operative positions in which they are shown by a control ring which is free to rotate with the wheel in the permitted sense (B) but prevented from rotating in the other sense (C) by the engagement of secondary pins between teeth on the inner periphery of the control ring and secondary teeth on the stationary member. If the wheel tends to counter-rotate in the sense (C) the teeth of the wheel drive the pins down the slots in the arrested control ring to their operative positions. When rotation of the wheel recommences in the permitted sense (B) the tendency of the control ring to lag behind causes the pins to be displaced to the radially outer ends of the slots so that there is no friction between the pins and the teeth of the stationary member. In a modification the secondary pins, the secondary teeth on the stationary member and the recesses in the inner periphery of the control ring are dispensed with and their functions are performed by additional pins between the teeth and located in slots in the control ring which have an opposite inclination to the remaining slots.
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