Closure cap

Abstract

A closure cap adapted for fitment to a container having a threaded neck terminating in a rim which defines an open mouth. The closure may be formed of a molding of elastomeric material and includes a top wall having an annular skirt downwardly depending therefrom. The annular skirt has a closure thread formed about its inside surface which cooperates with the threaded neck of the container to achieve the fitment. The closure cap also contains a stepped projection formed generally at the inside juncture of the top wall and the annular skirt. The stepped projection has a vertical surface thereon. A flexible, hollow frusto-conical flange is formed integrally with the inner surface of the top wall and projects downwardly and outwardly therefrom. The flange is sufficiently thin and has sufficient length so as to enable it to bend around the outside radius of the rim. As the closure cap is threaded onto the container, the flange is flexed upwards by the rim to form a top seal, and the flange is also bent around the outside radius of the rim to form a side seal between the vertical surface of the stepped projection and the outside surface of the container's neck. The gas-tight top and side seals formed by this closure cap makes it particularly desirable as a cap for a carbonated beverage bottle.