Piston-actuated dispensing pump

Claim 1

A RECIPROCATING PISTON PUMP FOR DISPENSING PUMPABLE MATERIAL OUT OF A CONTAINER, SAID PUMP COMPRISING A CLOSURE CAP FOR SAID CONTAINER, A PUMP CYLINDER CONNECTED TO SAID CAP, CHECK VALVE MEANS ARRANGED IN THE BOTTOM OF SAID CYLINDER, A SUCTION TUBE EXTENDING FROM THE BOTTOM OF SAID CYLINDER TO A LOCATION ADJACENT TO THE BOTTOM OF SAID CONTAINER, A TUBULAR PISTON SLIDABLY GUIDED WITHIN SAID CYLINDER AND EXTENDING UPWARDLY OUT OF SAID CYLINDER, AND OUTWARDLY THROUGH SAID CLOSURE CAP, SPRING MEANS ARRANGED WITHIN SAID CYLINDER AND SAID TUBULAR PISTON YIELDINGLY URGING SAID PISTON UPWARDLY INTO A NORMAL POSITION OF REST, SAID PISTON BEING ACTUATED FROM OUTSIDE AGAINST THE FORCE OF SAID SPRING MEANS, AN ELASTIC SEALING COLLAR PROVIDED AT THE LOWER END OF SAID TUBULAR PISTON SEALINGLY BEARING AGAINST THE CYLINDER WALL, FURTHER CHECK VALVE MEANS ARRANGED IN THE UPPER PART OF SAID TUBULAR PISTON, MEANS DEFINING AN OUTLET PASSAGE CONNECTED THROUGH SAID FURTHER CHECK VALVE MEANS TO THE INTERIOR OF SAID TUBULAR PISTON, AN ELASTIC ANNULAR FLANGE FORMED INTEGRALLY WITH SAID CLOSURE CAP AND PROJECTING WITH CLEARANCE DOWNWARDLY INTO SAID CYLINDER AND SURROUNDING SAID TUBULAR PISTON WITH CLEARANCE THEREBY DEFINING A FIRST ANNULAR GAP BETWEEN THE UPPER PART OF SAID CYLINDER WALL AND SAID ANNULAR FLANGE, SAID CYLINDER WALL HAVING AN APERTURE FORMED THEREIN THROUGH WHICH SAID FIRST GAP COMMUNICATES WITH THE INTERIOR OF SAID CONTAINER AND A SECOND ANNULAR GAP BETWEEN SAID TUBULAR PISTON AND SAID ANNULAR FLANGE COMMUNICATING WITH THE ATMOSPHERE, BOTH OF SAID GAPS AND SAID APERTURE DEFINING A PASSAGE ALLOWING ATMOSPHERIC AIR TO FLOW INTO SAID CONTAINER WHEN SAID TUBULAR PISTON IS DEPRESSED, AND SEALING MEANS MOVING WITH SAID PISTON AND COOPERATING WITH SAID ANNULAR FLANGE FOR CONTROLLING THE PASSAGE OF ATMOSPHERIC AIR INTO SAID CONTAINER, SAID SEALING MEANS FORMING A TIGHT SEAL WHEN SAID TUBULAR PISTON IS URGED BY SAID SPRING MEANS INTO SAID NORMAL POSITION OF REST.