Closure with vacuum indicating button.

摘要

A closure has a central button (24) has an "up" convex state from which it is movable by a vacuum within an associated container to a "down" concave state. The button (24), as formed, has a zero or tensile stress state with the stress state changing to a compressive stress state when the button (24) is drawn downwardly by said vacuum. This invention teaches that the button (24) be reformed (32-38) so that it is slightly flattened and the reforming changes the zero or tensile stress state to a compressive stress state thereby providing the button (24) with more stored energy when it is drawn downwardly by a vacuum within an associated container, thus providing a greater flipping action of the button capable of operating an irreversible tamper indicating system which may be applied to the button (24). <IMAGE>