Abstract: A directional control valve for liquid and gaseous fluids includes a valve piston and magnets controlling the valve piston and arranged at a distance at the end faces of the valve piston to define respective chambers therebetween. Flow forces prevailing during operation of the control valve and opposing the actuation force of the magnets are countered by providing a throttle in the connections to the tank to create a dynamic pressure to support the magnetic force. In order to limit the magnitude of the hydraulic force as provided by the dynamic pressure, the chambers in front of the end faces of the valve piston are connected to each other via two passageways in which a pressure relief valve is respectively arranged.

Abstract: The coupling and brake of a press receive pressurized fluid through a safety valve. The safety valve comprises two switching valves, so that if one of the switching valves fails and cannot close the other one can be closed. The safety valve is provided with a pressure-responsive switch which generates a shut-off signal commanding that the press be shut off, in response to a variety of malfunction situations, e.g., when the switching valves are closed but nevertheless a pressure build-up is occurring, or when the switching valves are open but the pressure being furnished to the coupling and brake does not reach or suddenly drops below the threshold levels to which the coupling and brake can respond.