Patent ID: 7568587

Claim:
A lugged metal cap for a container designed to package and hold products stored therein under pressure, said cap comprising a top panel, a generally cylindrical side wall integral with and depending from a periphery of said top panel, an outwardly curled rim extending around a lower edge of said side wall, and a plurality of cap lugs formed on said rim extending inward thereof; the improvement comprising a central coined band formed in said top panel radially inward of the periphery of said top panel and having a cross-sectional thickness less than the adjacent portions of said top panel, a central area of said top panel surrounded by said coined band being normally depressed with respect to a remaining area of said top panel, said coined band and said central area surrounded by said coined band being pre-stressed so as to snap normally downward of the top panel, whereby when the cap is attached and sealed to a filled and internally pressurized container, the central area of the top panel will snap upwardly in response to internal pressure, and at a later time will snap downwardly so as to signal a loss of internal pressure within the container.