Device for controlling a longitudinally movable driving means

摘要

A device for controlling both the displacement of, and the transmittal of force by, a longitudinally movable driving apparatus comprising a piston rod which is hydraulically movable inside a cylinder, an emitter and receiver for ultrasonic waves, which are transmitted between a movable and a fixed part of the driving apparatus, a logic circuit and a controllable source of force, said receiver being electronically connected to said controllable source of force via said logic circuit.