Fluid pressure control system and valve therefor

Claim 1

A VEHICLE BRAKE SYSTEM INCLUDING A MAIN PRESSURE RESERVOIR, AN EMERGENCY PRESSURE RESERVOIR, A PRESSURE CONDUIT BETWEEN SAID RESERVOIRS, A CHECK VALVE IN SAID CONDUIT TO PERMIT PASSAGE OF PRESSURE FROM SAID MAIN TO SAID EMERGENCY RESERVOIR AND TO PRECLUDE PASSAGE OF PRESSURE IN THE OPPOSITE DIRECTION, A SECOND PRESSURE CONDUIT EXTENDING FROM SAID MAIN RESERVOIR AND DISCHARGING INTO ONE SIDE OF A TWO-WAY CHECK VALVE, A THIRD PRESSURE CONDUIT EXTENDING FROM SAID EMERGENCY RESERVOIR AND DISCHARGING INTO THE OPPOSITE SIDE OF SAID TWO-WAY CHECK VALVE, A FOURTH PRESSURE CONDUIT EXTENDING FROM SAID TWO-WAY CHECK VALVE AND AND DISCHARGING INTO A PLURALITY OF SPRING-APPLIED, PRESSURE-RELEASE BRAKE-ACTUATING MEMBERS, A FIRST CONTROL VALVE IN SAID SECOND PRESSURE CONDUIT, A SECOND CONTROL VALVE IN SAID THIRD PRESSURE CONDUIT, EACH OF SAID CONTROL VALVES HAVING A VENT PASSAGE TO ATMOSPHERE, EACH OF SAID CONTROL VALVES HAVING A MANUALLY OPERABLE HANDLE ELEMENT EXTENDING THEREFROM, EACH OF SAID HANDLE ELEMENTS BEING MOVABLE IN ONE DIRECTION TO PERMIT PASSAGE OF FLUID PRESSURE THROUGH ITS ASSOCIATED CONDUIT AND MOVABLE IN THE OPPOSITE DIRECTION TO PRECLUDE SAID PASSAGE OF FLUID PRESSURE AND TO VENT THE DOWNSTREAM PORTION OF ITS ASSOCIATED CONDUIT TO ATMOSPHERE, SAID FIRST CONTROL VALVE HAVING ELEMENTS EFFECTIVE TO MAINTAIN THE POSITION IN WHICH THEY ARE PLACED IN RESPONSE TO FLUID PRESSURE ENTERING SAID FIRST CONTROL VALVE, SAID SECOND CONTROL VALVE BEING YIELDINGLY URGED INTO VENTING POSITION.