Today in 1971, US Patent 3554400 A was issued, an invention of John S. Bozek, assigned to the Continental Can Co., for his “Nonflipping Beer Can End.” Here’s the Abstract:

An easy opening end particularly adapted for use on beverage cans, said end including an end panel, weakening line formed in said end panel and defining a removable tearout portion which extends generally from the central portion of said end panel to the periphery of said end panel, and a circumferential rib in said end panel, said rib being generally C-shaped in outline and having opposite ends terminating adjacent said tearout portion and reinforcing said end panel around said tearout portion to prevent premature rupturing of said can end along said weakening line, and a pull tab secured to said tearout portion for effecting the removal thereof, said rib being depressed to define an upwardly opening groove, and said pull tab having a free end overlying said groove whereby clearance is provided between said pull tab free end and said end panel to facilitate the initial lifting of said pull tab.