Reciprocating pump for an implantable medication dosage device

摘要

A reciprocating pump suitable for use in an implantable medication dosage device has a piston movable in a chamber connected to a medication reservoir, the chamber having an output closable by a check valve. The check valve includes a movable element which is acted upon by a biasing system to urge the moveable element in a direction to close the check valve. The moveable element has a sealing surface against which an end face of the piston presses with tight adjacency as the piston moves to an extreme position during its output stroke.