Today in 1955, US Patent 2698994 A was issued, an invention of Walter M. Hansen, for his “Beer Can Opener.” There’s no Abstract, although in the description it includes this summary:

This invention relates to a can opening device and more particularly to a high speed opener of the performating type.

The conventional practice of storing liquids for customer consumption in cans has presented a problem for operators of restaurants and taverns who necessarily handle a large volume of canned liquids in this form such as beer and fruit juices. The usual practice is to punch a hole in the tops of the cans through which the content is poured into the customers glass. Prior to this time such a can punching operation has not only proved dangerous and laborious but also time consuming in that seldom was the punch conveniently located and its use required two hands, one hand to hold the can while the other hand was used to do the punching. Injuries are likely to occur in case of slippage of the can from the hand of the opener.

It is therefore among the objects and purposes of this invention to provide a high speed can opener requiring only a straight thrust by one hand of the operator used to grasp the can wherein a pivoted cutting blade is brought into cutting engagement with the top of the can.