Push-actuated drain valve

Claim 1

IN A PUSH-ACTUATED DRAIN VALVE DEVICE FOR OPENING AND CLOSING-OFF FLUID FLOW THROUGH AN OPEN DRAIN PORTION, A HOUSING FITTING FOR REMOVABLY-MOUNTING IN THE OPEN DRAIN PORTION, SAID FITTING HAVING AN OPEN INLET PORTION FOR RECEIVING THE FLUID TO BE DRAINED AND HAVING AN OPEN OUTLET PORTION TO DELIVER THE DRAINED FLUID, AN ANNULAR SEATING FLANGE EXTENDING TRANSVERSELY FROM SAID INLET END PORTION AND DEFINING A VALVE SEATING SURFACE ABOUT THE OPENING TO SAID INLET END PORTION, A CENTRALLY-POSITIONED MOUNT CARRIED BY SAID OUTLET END PORTION, A COOPERATING PAIR OF SLEEVE-LIKE FRONT AND BACK HOUSING PARTS FOR RELATIVE LONGITUDINAL SLIDING MOVEMENT WITH RESPECT TO EACH OTHER WITHIN SAID FITTING, MEANS COOPERATING WITH SAID BACK HOUSING PART FOR REMOVABLY-SECURING SAID HOUSING PARTS ON SAID MOUNT IN A RADIALLY-SPACED RELATION WITHIN AND ALONG SAID FITTING TO DEFINE A DRAIN PASSAGEWAY THEREWITH THAT EXTENDS FROM SAID SEATING FLANGE, SAID FRONT HOUSING PART HAVING A FRONT END PORTION PROJECTING LONGITUDINALLY-OUTWARDLY BEYOND SAID SEATING FLANGE, PUSH BUTTON MEANS REMOVABLY-MOUNTED ON SAID FRONT END PORTION, A RESILIENT VALVE REMOVABLY-POSITIONED BETWEEN SAID FRONT END PORTION AND THE UNDERSIDE OF SAID PUSH BUTTOM MEANS AND HAVING A FLAP BODY PROJECTING TRANSVERSELY-OUTWARDLY FOR MOVEMENT INTO AND OUT OF SEATING ENGAGEMENT WITH SAID SEATING FLANGE TO OPEN AND CLOSE-OFF FLUID FLOW THROUGH SAID PASSAGEWAY, AND SAID PUSH BOTTOM MEANS HAVING AN ANNULAR OFFSET PORTION ON ITS UNDERSIDE DEFINING A RELIEF AREA FOR SAID FLAP BODY WHEN SAID PUSH BUTTOM IS FULLY DEPRESSED WITH RESPECT TO SAID SEATING FLANGE.