Patent ID: 7631663

Claim:
A pilot valve comprising: an actuating motor and a hydraulic preamplifier including a bounce plate disposed between first and second control nozzles and movable by the actuating motor; corresponding nozzle ducts and inlet diaphragms connected to the first and second control nozzles, respectively, to vary a control oil volume guided by the nozzle ducts and the inlet diaphragms; wherein the nozzle ducts branch off a pressure terminal guiding a supply pressure of a main stage, and downstream of the inlet diaphragms a respective control duct branching off the nozzle ducts is connected to a respective control terminal to which the control chambers of the main stage are connected; and wherein a control pressure difference is applied to the control terminals independently of the control of the actuating motor using a manually actuated blocking mechanism that closes at least one of the nozzle ducts.