Electrohydraulic units for controlling hydraulic transducers

Claim 1

AN ELECTROHYDRAULIC UNIT FOR CONTROLLING HYDRAULIC TRANSDUCERS, COMPRISING, A TWO-POSITION SLIDE-VALVE CONNECTABLE TO A PRESSURE-FLUID SOURCE, IN WHICH ONE OF SAID POSITIONS CAUSES SAID SOURCE TO BE CONNECTED TO AT LEAST ONE TRANSDUCER AND THE OTHER CAUSES SAID TRANSDUCER TO BE DISCHARGED, A SOLENOID BEING PROVIDED TO CONTROL THE SLIDEVALVE POSITION, CHARACTERIZED IN THAT SAID SOLENOID CONTROLS A SLIDE-VALVE GOVERNING VALVE AND IN THAT SAID SLIDE-VALVE COMPRISES, FOR THE GOVERNING THEREOF, A CASING WITH TWO CHAMBERS FOR CONTROLLING SAID SLIDE-VALVE THAT ARE PERMANENTLY CONNECTED TO SAID SOURCE AND SO DEVISED THAT SAID PRESSURE-FLUID EXERT OPPOSING FORCES THEREIN ON SAID SLIDEVALVE, THE LATTER HAVING A LARGER EFFECTIVE CONTROL SURFACE AREA IN ONE OF SAID CHAMBERS, WHICH CHAMBER IS SUPPLIED THROUGH A CONSTRICTED PASSAGE AND CONNECTED THROUGH A PASSAGE CONTROLLED BY SAID SLIDE-VALVE TO A DISCHARGE PIPE WHICH IS CLOSED OR OPENED BY SAID VALVE AND ON THE CLOSURE OR OPENING OF WHICH THE TWO SAID SLIDEVALVE POSITIONS ARE DEPENDENT, THAT IS TO SAY THAT WHEN SAID VALVE IS OPEN ONE OF THE SLIDE-VALVE POSITIONS IS THAT WHEREIN SAID CONTROLLED PASSAGE IS PARTLY UNCOVERED BY THE SLIDE-VALVE AS THE RESULT OF A BALANCING OF THE OPPOSING FORCES EXERTED THEREON WITH DIFFERENT PRESSURES, WHEREAS WHEN, ON THE CONTRARY, SAID VALVE IS CLOSED, THE SLIDE-VALVE IS LOCATED IN ITS OTHER POSITION AS A RESULT OF THE PREPONDERANT INFLUENCE OF THE CONTROLLING PRESSURE IN THE CHAMBER IN WHICH THE EFFECTIVE SLIDE-VALVE AREA IS GREATER.