Discharge valve construction for dispenser pump

Claim 1

A DISPENSING PUMP CONSTRUCTION COMPRISING, IN COMBINATION: (A) A CYLINDER, (B) A PISTON MOVABLE IN THE CYLINDER, HAVING AN OPERATING STEM WITH A THROUGH AXIAL BORE CONSTITUTING A DISCHARGE CHANNEL FROM THE INTERIOR OF THE CYLINDER, SAID STEM HAVING INTERMEDIATE ITS ENDS AND INTERNAL ANNULAR SHOULDER CONSTITUTING A DISCHARGE VALVE SEAT, AND (C) A DISCHARGE VALVE DISPOSED IN SAID AXIAL BORE, SAID VALVE BEING ENGAGEABLE WITH THE VALVE SEAT TO CLOSE THE DISCHARGE CHANNEL AND HAVING A STEM EXTENDING OUT OF THE CHANNEL, (D) AN ACTUATOR BUTTON CARRIED ON THE END OF THE PISTON STEM, (E) MEANS ANCHORING THE VALVE STEM TO THE CYLINDER, SAID MEANS THUS EFFECTING AN ANCHORAGE OF THE DISCHARGE VALVE WHEREBY ACTUATION OF THE BUTTON, THE PISTON STEM AND THE PISTON TO MOVE THE LATTER FURTHER INTO THE CYLINDER EFFECTS A SEPARATION OF THE VALVE FROM THE VALVE SEAT, (F) SAID PISTON STEM AND PISTON BEING OF INTEGRAL MOLDED RESILIENT PLASTIC SUBSTANCE, (G) SAID VALVE BEING SLIGHTLY LARGER IN DIAMETER THAN THE OPENING OF THE VALVE SEAT, (H) SAID VALVE SEAT BEING CIRCUMFERENTIALLY EXPANSIBLE WITHIN LIMITS AND CAPABLE OF SUFFICIENT EXPANSION TO ENABLE THE VALVE TO BE FORCED THROUGH IT WHEREBY THE VALVE STEM EXTENDS THROUGH THE SEAT, AND (I) SAID VALVE STEM EXTENDING THROUGH AND OUT OF THE PISTON TO THE CYLINDER END WHICH IS BEYOND THE PISTON.