Four-chamber cylinder for a hydraulic actuator with emergency function and hydraulic actuator so that

摘要

Disclosed is a four-chamber cylinder with Notschließfunktion having two piston devices, each having a piston and a piston rod. Each piston defines two mutually opposing chambers, one of which is used in normal operation for pressing the piston device to the other piston device, while the other chamber is used to move the adjoining piston devices in one of the two actuating directions. The two piston rods are directed towards each other, wherein the one piston rod can dip telescopically in a guide recess of the other piston rod. In normal operation of the four-chamber cylinder, an emergency spring is held under prestress, in which the two piston devices are pressed against each other. Thus, a compact four-chamber cylinder is created, which is used to set a valve, a turbine or a process fitting, are placed on the increased safety requirements. With the four-chamber cylinder according to the invention, an adjusting movement is possible even in the event of failure of a supply via the emergency spring, wherein the four-chamber cylinder can be installed and operated bidirectionally.