Patent ID: 6957752

Claim:
A dispenser comprising: a body defining a chamber for receiving a substance; a dispensing tip defining at least one opening coupled in fluid communication with the chamber; a piston mounted within the body; a plurality of drive surfaces formed on one of the piston and body, and a plurality of stop surfaces formed on the other of the piston and body, wherein at least one of the piston and body is rotatable in a first direction relative to the other in predetermined increments to dispense metered amounts of substance from the chamber through the dispensing tip, and a plurality of the drive surfaces and stop surfaces cooperate to prevent movement of least one of the piston and body relative to the other in a second direction; and a one-way valve including an axially-elongated valve seat, and an axially-elongated flexible valve member secured to the valve seat and defining a normally-closed valve opening at the interface of the valve member and valve seat that is connectable in fluid communication with the opening to dispense metered amounts of substance therethrough.