Today in 1980, US Patent 4219578 A was issued, an invention of George J. Collias, assigned to the Kepros-Ganes Company, for his “Method For Preventing Buckle of Beer-Can Tops During Pasteurization.” Here’s the Abstract:
A method is described for preventing buckling of beer-can tops during pasteurization of the beer. Prior to the pasteurization, an anti-buckle ring is mated with each beer can such that the ring captures the double-seamed top of the can. The ring prevents radial displacement at key points of the top and, hence, buckling of the top end of the can, when the heat applied during pasteurization causes the internal pressure of the can to increase. After pasteurization, the ring is automatically removed from the can for further use with another can.