Valves for pressurized dispensing containers

Claim 1

A valve for a pressurized dispensing container and comprising a valve housing defining a valve chamber and having at its lower end an inlet for pressurized material, an annular flexible seal clamped into position closing the upper end of the chamber, a cup-shaped valve member within the chamber, a hollow actuator stem extending in sliding, sealed relation through the seal and engaging the valve member at its lower end, and a spring urging the valve member upwardly into sealing engagement with the seal, the actuator stem being manually moveable downwardly against the action of the spring to unseat the valve member and open the valve, in which the wall of the actuator stem includes at least one radial aperture adjacent to but spaced from the lower end of the actuator stem and of a height dimension sufficiently greater than the thickness of said flexible seal that a substantial portion of a entire peripheral segment of the inner annulus of said flexible seal is not in contact with an outer surface of said stem and can expand to protrude inwardly of said aperture when said aperture and seal are in the same plane, thereby defining a lip extending along the lower portion of said aperture against which said flexible seal non-stem contacting segment is engageable upon withdrawal of said actuator stem from engagement with said valve member, the aperture placing the interior of the actuator stem in communication with the interior of the valve member and the lip portion serving to restrain the lower end of actuator stem from passing through the seal if the actuator stem is moved upwardly of the seal.