Fluid dispensing pump with sealing means

Claim 1

IN A FLUID DISPENSING PUMP, THE COMBINATION WITH A GENERALLY VERTICAL CYLINDRICAL PUMP BARREL HAVING AT ITS UPPER END A COLLAR, OF A PLUNGER RECIPROCALLY DISPOSED IN SAID BARREL AND HAVING AT ITS UPPER END AND ABOVE SAID COLLAR A DISCHARGE HEAD HAVING A DISCHARGE ORIFICE FOR FLUID, SPRING MEANS ACTING BETWEEN SAID BARREL AND PLUNGER FOR URGING SAID PLUNGER UPWARDLY IN SAID BARREL, A CHECK VALVE ASSOCIATED WITH SAID BARREL TO PREVENT DOWNWARD MOVEMENT OF FLUID THEREIN, SAID PLUNGER BEING FORMED TO PROVIDE A DISCHARGE PASSAGE EXTENDING THERETHROUGH AND COMMUNICATING WITH SAID DISCHARGE OFRIFICE, MEANS ACTING BETWEEN SAID HEAD AND SAID COLLAR TO HOLD SAID HEAD AND PLUNGER IN A DEPRESSED AND IMMOBILIZED POSITION AGAINST THE ACTION OF SAID SPRING MEANS, SEALING MEANS ACTING BETWEEN SAID HEAD AND COLLAR, SAID SEALING MEANS BEING RENDERED OPERATIVE WHEN SAID PLUNGER IS DEPRESSED AND IMMOBILIZED TO SEAL SAID BARREL TO PREVENT LEAKAGE EXTERNALLY OF SAID PLUNGER, AND MEANS OPERABLE WHEN SAID PLUNGER IS DEPRESSED AND IMMOBILIZED TO SEAL SAID DISCHARGE PASSAGE TO PREVENT LEAKAGE INTERNALLY OF SAID PLUNGER, SAID LAST NAMED MEANS COMPRISING COACTING SEALING SURFACES RELATIVELY DISPLACED INTO ENGAGEMENT TO BLOCK FLOW OF LIQUID THROUGH THE DISCHARGE PASSAGE AND HENCE TO SAID ORIFICE, SAID FIRST NAMED SEALING MEANS COMPRISING A DEPENDING ANNULAR FLANGE ON SAID HEAD HAVING A PERIPHERAL BEAD THEREON, A FIRST SURFACE ON SAID COLLAR ENGAGED BY SAID BEAD, AND A SECOND SURFACE ON SAID COLLAR FORMING AN ACUTE ANGLE WITH SAID FIRST SURFACE AND ENGAGING SAID FLANGE WHEN SAID HEAD AND PLUNGER OCCUPY SAID DEPRESSED AND IMMOBILIZED POSITION TO EXPAND SAID FLANGE AND THEREBY TO APPLY PRESSURE BETWEEN SAID BEAD AND SAID FIRST SURFACE ON SAID COLLAR.