Today in 1947, US Patent 2422750 A was issued, an invention of Harold E. Rue, assigned to Pabst Brewing Co., for his “Plastic Bottle Crowner.” There’s no Abstract, although in the description it includes this summary:

This invention appertains to bottle capping and more particularly to a novel machine for forming or molding plastic crown caps on bottle necks to bring about the tight sealing of the bottles.