Abstract: A closure set within an aperture of a container end wall, such as a beverage container, whereby pressurized gasses within the container force bias a tapered sealing panel into gas tight sealing engagement within a complementary tapered rim seal. An enclosing cover, providing contamination protection, is rotated open, uncovering a vent hole, exhausting pressurized gasses prior to the tapered sealing panel being opened, such as to provide a pour opening. Rotation of the cover actuates co-joined levers that transfer a force to automatically open or close the tapered sealing panel. A space located on the inside surface of the cover is first available to a user, containing indicia and promotional messages on initial opening of the container.

Abstract: A closure, set within an aperture of a container end wall, for gas tight containment of dissociating gasses that emit from carbonated beverage, whereby the container, such as a beverage container, becomes pressurized. The closure device, manufactured of a suitable plastic material, set within an aperture in a container end wall, includes a rim seal with an annular locking recess surrounding the aperture in the container end wall, providing a liquid and gas-tight seal. The rim seal includes a depending tapered inner wall, protruding into the container interior, with the larger diameter open to the container interior. Additionally, the rim seal is fitted with a narrow strip hinge on a lower aspect, and locking members located on an upper aspect. A sealing panel, having a small diameter gas vent hole, is set within the rim seal, connected by the narrow strip hinge. This panel is formed with a tapered outer depending wall with a like taper to the rim seal, such that the tapers cooperate in sealing engagement.