Bottle stoppers or closures

Claim 1

A bottle stopper having a head and a stem engageable respectively, over the mouth and against the internal surface of the neck of a bottle when fitted to a bottle wherein the head and the stem have a continuous passage therethrough, the passage having from stem to head, a frusto conical portion feeding into a restriction beyond which is an open-ended chamber, a valve located in said passage and resiliently urged into a closed position to close off said passage but yieldable to open when pressure in the bottle exceeds the resilient pressure, the valve comprising a resiliently-loaded stop, a seat for the resiliently-loaded stop being afforded at the stem-remote side of the restriction, the stop being located in the chamber acting against the seat provided at the outlet of said restriction, the stop having a disc from one side of which axially extends a spindle and in opposite side a recess is provided to locate a seal for urging against the seat, and a retaining cap having an axial aperture through which projects the top of the spindle, the cap being secured in a groove in the wall of the chamber with a resilient-biasing for the stop being located between the disc and cap.