| 摘要 |
A linear actuator comprises a threaded spindle (4) rotatable in either direction, a threaded bushing (9) that drives an output rod (11) and a reversible motor (12) that drives the spindle via a power transmission (13). In certain cases such as hospital beds it might be desired instantly to arrive at one or the other extreme position or an intermediate position from a random position. This is achieved by a power transmission which by a coil spring can be disconnected from the spindle which is not of the self locking type. The disconnection is caused by the ends of the coil spring being enveloped by and embedded in two cylindrical caps (7,10) that can slide inside one another and are connected such that they by a compression perform a mutual rotation whereby the coil spring can be released. <IMAGE> |
