Anti-reversal device.

摘要

An anti-reversal device is provided whereby a wheel (10) and shaft (11) are free to rotate in one sense (B) relative to a stationary member (12) but are prevented from counter-rotating in the sense (C) by engagement of load-bearing pins (26) between teeth (16 and 17) of the respective members (10, 12). The pins (26) are positively driven to the operative positions in which they are shown by a control ring (19) which is free to rotate with the wheel (10) in the permitted sense (B) but prevented from rotating in the other sense (C) by the engagement of secondary pins (24) between teeth (21) on the inner periphery of the control ring (19) and secondary teeth (20) on the stationary member (12). If the wheel (10) tends to counter-rotate in the sense (C) the teeth (16) of the wheel (10) drive the pins (26) down the slots (25) in the arrested control ring (19) to their operative positions. When rotation of the wheel (10) recommences in the permitted sense (B) the tendency of the control ring (19) to lag behind causes the pins (26) to be displaced to the radially outer ends of the slots (25) so that there is no friction between the pins (26) and the teeth (17) of the stationary member (12).

In a modification the secondary pins (24), the secondary teeth (20) on the stationary member (12) and the recesses (21) in the inner periphery of the control ring (19) are dispensed with and their functions are performed by additional pins between the teeth (16) and (17) located in slots in the control ring (19) which have an opposite inclination to the remaining slots (25).