Patent ID: 6067021
Filing Date: 2000-05-23
Classification: E05F,E05Y,F15B

Abstract:
Apparatus for hydraulically operating a movable part attached to a vehicle, comprising at least one double-acting hydraulic working cylinder, which is connected between the vehicle and the movable part, wherein working chambers of the working cylinder are connected by connection lines with respective sides of a switched pressure source, said connection lines including respective check valves, wherein both of the check valves have a mutually releasing device and each of the working chambers connected to the respective check valves is maintained at a predetermined pressure level via a pre-stress valve which drains into a tank, and wherein a line which extends to said tank is connected to at least one said connection line, said line including a proportional pressure valve controlled by control electronics and is equal to the exact pressure that is necessary for movement of the movable part.