Load-adjusted relay valve device for brake control systems

Claim 1

A FLUID PRESSURE REGULATING VALVE DEVICE COMPRISING: (A) A CASING HAVING AN INLET PRESSURE CHAMBER TO WHICH A CONTROL PRESSURE MAY BE SUPPLIED AND AN OUTLET PRESSURE CHAMBER FROM WHICH FLUID PRESSURE IS SUPPLIED FOR A DESIRED CONTROL PURPOSE, (B) A CONSTANT AREA PISTON HAVING A HOLLOW STEM AND SUBJECT ON ONE SIDE TO THE FLUID PRESSURE IN SAID INLET PRESSURE CHAMBER, (D) A VARIABLE AREA DIAPHRAGM CONNECTED AT ITS INNER AREA TO SAID PISTON STEM AND AT ITS OUTER PERIPHERY TO SAID CASING AND BEING SUBJECT ON SIDE TO THE PRESSURE IN SAID OUTLET PRESSURE CHAMBER, (D) A VALVE STEM COAXIALLY CARRIED BY SAID PISTON AND HAVING: (I) A SUPPLY VALVE AT ONE END WHICH IS BIASED TO A SEATED POSITION ON A VALVE SEAT ON SAID PISTON TO CLOSE COMMUNICATION THEREPAST BETWEEN SAID INLET PRESSURE CHAMBER AND SAID OUTLET PRESSURE CHAMBER, AND (II) AN EXHAUST VALVE AT THE OPPOSITE END THEREOF, (E) A TUBULAR EXHAUST VALVE SEAT MEMBER HAVING A VALVE SEAT AT ONE END ON WHICH SAID EXHAUST VALVE SEATS TO CLOSE COMMUNICATION BETWEEN SAID OUTLET PRESSURE CHAMBER AND ATMOSPHERE VIA A PASSAGE IN SAID TUBULAR EXHAUST VALVE SEAT MEMBER, (F) A LEVER HAVING ONE END PIVOTALLY SUPPORTED ON SAID CASING AND A FREE END THEREOF OPERATIVELY CONNECTED TO SAID EXHAUST VALVE SEAT MEMBER FOR AXIALLY SHIFTING SAID EXHAUST VALVE SEAT MEMBER TO DIFFERENT POSITIONS TO VARY THE NORMAL CLEARANCE BETWEEN SAID EXHAUST VALVE AND SAID EXHAUST VALE SEAT, (G) ROTARY CAM MEANS FOR OPERATIVELY PIVOTING SAID LEVER FOR EFFECTING SHIFTING OF SAID EXHAUST VALVE SEAT MEMBER TO ITS SAID DIFFERENT POSITONS, (H) MEANS FOR ROTATING SAID ROTARY CAM MEANS FOR EFFECTING PIVOTING OF SAID LEVER IN ACCORDANCE WITH VARIATIONS IN VEHICLE LOAD, (I) SAID CONSTANT AREA PISTON BEING EFFECTIVE RESPONSIVELY TO SUPPLY OF FLUID PRESSURE TO SAID INLET PRESSURE CHAMBER TO MOVE THE INNER AREA OF SAID DIAPHRAGM TO PROVIDE AN INCREASINGLY LARGER EFFECTIVE PRESSURE AREA TO A LIMIT DETERMINED BY SEALING ENGAGEMENT OF SAID EXHAUST VALVE ON SAID EXHAUST VALVE SEAT, THEREBY TO EFFECT UNSEATING OF SAID SUPPLY VALVE CORRESPONDINGLY TO CAUSE SUPPLY OF FLUID PRESSURE PAST SAID SUPPLY VALVE FROM SAID INLET PRESSURE CHAMBER TO SAID OUTLET PRESSURE CHAMBER, THE PRESSURE ESTABLISHED THEREIN ACTING ON SAID DIAPHRAGM TO EFFECT RESEATING OF SAID SUPPLY VALVE ON SAID PISTON BY RETURN MOVEMENT OF SAID PISTON AND CORRESPONDING TO THE POSITION OF SAID EXHAUST VALVE SEAT MEMBER, (J) A PLURALITY OF ANGULARLY SPACED RADIALLY EXTENDING RIBS CARRIED BY SAID CASING AND SUPPORING SAID DIAPHRAGM AGAINST DEFLECTION BY THE PRESSURE IN SAID OUTLET CHAMBER, AND (K) A PLURALITY OF ANGULARLY SPACED RIBS CARRIED BY SAID PISTON IN INTERSPERSED RADIAL RELATION TO THE AFORESAID RIBS CARRIED BY SAID CASING AND EFFECTIVE TO PEEL OFF THE INNER AREA OF THE DIAPHRAGM TO PROVIDE THE INCREASINGLY GREATER EFFECTIVE AREA OF THE DIAPHRAGM IN ACCORDANCE WITH MOVEMENT OF SAID PISTON WHEN SUBJECT TO THE PRESSURE IN THE INLET PRESSURE CHAMBER.