Step-up relay valve

Claim 1

IN A RELAY VALVE OF THE STEP-UP TYPE WHICH INCLUDS A CASING HAVING A PRESSURE SUPPLY PORT, A PRESSURE DELIVERY PORT, A PRESSURE CONTROL PORT AND AN EXHAUST PORT, DELIVERY AND EXHAUST VALVES CONSTRUCTED AND ARRANGED TO CONTROL COMMUNICATION BETWEEN SAID SUPPLY AND DELIVERY PORTS AND BETWEEN THE DELIVERY AND EXHAUST PORTS, RESPECTIVELY, AND MEANS FOR BIASING THE DELIVERY AND EXHAUST VALVES TOWARD CLOSED POSITION, THE IMPROVEMENT WHICH COMPRISES AN ANNULAR RATIO RING AND A COOPERATING PISTON, MEANS FOR BIASING SAID PISTON IN OPPOSITION TO THE CONTROL PRESSURE, FOR DELIVERY AND EXHAUST VALVES BEING RELATED WITH EACH OTHER AND WITH THE PISTON SO THAT THEY MAY EITHER BOTH BE CLOSED OR ALTERNATELY OPEN, THE EXHAUST VALVE BEING CLOSED AND THE DELIVERY VALVE OPENED BY AN INCREASE IN CONTRROL PRESSURE ACTING ON ONE SIDE OF THE PISTON SUFFICIENT TO OVERCOME THE EFFECT OF BOTH SAID BIASING MEANS AND THE FORCE OF THE DELIVERY PRESSURE ACTING ON THE REVERSE SIDE OF THE PISTON, SAID RING AND PISTON COACTING TO SEPARATE THE CASING INTO CONTROL AND DELIVERY CHAMBERS RESPECTIVELY COMMUNICATING WITH THE CONTROL PORT AND THE DELIVERY PORT, SAID RATIO RING HAVING AN INNER AND OUTER SPACED-APART WALLS DEFINING AN OPEN CHANNEL, SAID OUTER WALL SEALINGLY ENGAGING THE WALL OF THE CASING SURROUNDING THE CONTROL CHAMBER AND SAID INNER WALL HAVING THE SIDE THEREOF OPPOSITE SAID CHANNEL EXPOSED TO THE INTERIOR OF SAID DELIVERY CHAMBER, SAID PISTON HAVING A DEPENDING SKIRT PROVIDED WITH AN ANNULAR FLANGE POSITIONED WITHIN SAID CHANNEL AND SLIDINGLY AND SEALINGLY ENGAGING CONFRONTING SURFACES OF SAID WALLS WHEREBY THE AREA OF THE PISTON EXPOSED TO PRESSURE IN SAID DELIVERY CHAMBER IS LESS THAN THE AREA OF THE PISTON EXPOSED TO PRESSURE IN SAID CONTROL CHAMBER BY AN AMOUNT EQUAL TO THE ANNULAR AREA OF SAID CHANNEL BETWEEN SAID WALLS.