Master cylinder

Claim 1

IN A HYDRAULIC BRAKE SYSTEM FOR A VEHICLE, A HOUSING HAVING A CYLINDRICAL BORE, PRIMARY AND SECONDARY PISTONS IN SAID BORE TO DEFINE PRIMARY AND SECONDARY FLUID CHAMBERS AND A VALVE CHAMBER, FRONT AND REAR WHEEL BRAKES OPERABLE RESPONSIVE TO FLUID PRESSURE IN SAID PRIMARY AND SECONDARY FLUID CHAMBERS RESPECTIVELY, COMPRESSION SPRINGS IN SAID FLUID CHAMBERS TO YIELDABLY RESIST MOVEMENT OF SAID PISTONS RESPONSIVE TO AN INCREASE OF FLUID PRESSURE IN SAID VALVE CHAMBER, A SLEEVE VALVE SLIDABLY MOUNTED IN ONE END OF THE HOUSING AND HAVING ITS INNER END EXTENDING THROUGH THE VALVE CHAMBER INTO ABUTTING ENGAGEMENT AGAINST SAID PRIMARY PISTON, SAID VALVE HAVING AN AXIAL PASSAGE AND AN INLET PORT LEADING FROM THE VALVE CHAMBER TO SAID AXIAL PASSAGE, SAID VALVE HAVING AN OUTLET PORT LEADING FROM SAID AXIAL PASSAGE TO AN OUTLET PASSAGE IN THE HOUSING WHEN SAID VALVE IS IN ITS RETRACTED BRAKE RELEASE POSITION, SAID HOUSING HAVING A FLUID INLET PASSAGE LEADING TO SAID VALVE CHAMBER, MEANS FOR SUPPLYING FLUID UNDER PRESSURE THROUGH SAID FLUID INLET PASSAGE INTO SAID VALVE CHAMBER, AND MEANS TO MOVE SAID SLEEVE VALVE AND PRIMARY PISTON INWARDLY TO GRADUALLY MOVE THE OUTLET PORT OUT OF REGISTRY WITH SAID OUTLET PASSAGE TO THEREBY INCREASE THE FLUID PRESSURE WITHIN THE VALVE CHAMBER.