Abstract: The hydraulic control valve as described includes two precontrol valves, each of them capable of operating the valve slide element in a primary control fashion while the respective other of the precontrol valve performs auxiliary functions so that in total two sets of outputs can be controlled whereby in each case the secondary control function can be carried out persistently or intermittently for the duration of persistence of the primary control function.

Abstract: The control valve for an hydraulic actuator is provided with a particular operating state for venting the hydraulic system, which state is attainable positively whenever the hydraulic pressure is inadequate, e.g., in the case of venting or presence of air bubbles; a pressure-monitoring element permits positively the slide element of the control valve to be placed into the venting disposition, in that a particular stop on the slide rod cooperates with a plunger extending from the monitoring cylinder and being subject to the differential force between a spring and system pressure.