| 摘要 |
A rotary mechanism for incrementally advancing a first circular bearing member 13 with respect to a second circular bearing member 12 comprises a unidirectional clutch 41 and a rotary actuator 21, 33, 39. Actuation of the actuator 21, 33, 39 is against a resilient bias 34, and overcomes friction between the first circular bearing member 13 and the second circular bearing member 12 to advance the first circular bearing member 13 with the unidirectional clutch 41 locked. Release of the actuator 21, 33, 39 allows resetting thereof by the resilient bias 34, the friction between the first circular bearing member 13 and the second circular bearing member 12 resisting further relative movement. |
