Today in 1943, US Patent 2333088 A was issued, an invention of Raymond M. Brown, for his “Bottle Opener.” There’s no Abstract, although in the description it includes this summary:

One of the objects of the present invention is to provide a bottle opener of the type described, having one or more back stops adjacent the prying lip and slightly spaced therefrom which permit the prying lip to exercise its function of detaching the cap, but which may contact with the flange of the cap as to spread andthereby limit the extent to which it can be flared, thus preventing the bending of the disk of the cap under any circumstances and particularly under the conditions of sudden operation above referred to.

Another object of the invention is to provide a pair of spaced back stops preferably symmetrically arranged with respect to the apex of the prying lip, permitting the latter, if necessary, to bulge the flange between the back stops by drawing upon the fullness of the flutes of the flange beyond said back stops, the metal moving.