Control mechanism

摘要

A mechanism for controlling the position of a movable member and for locking it in any desired position comprising a hydraulic displacement device movable with the member and a slide valve hydraulically connected to the displacement device to control flow of liquid to or from the device. The slide valve includes a pre-loaded spring, capable in the absence of other force of moving the slide valve to its closed position to lock the member against movement. A force motor is operable when desired to move the slide valve to its open position to permit movement of the member.