Today in 1936, US Patent 2056524 A was issued, an invention of Paul A. Johnson, for his “Combination Bushing For Beer Barrels.” There’s no Abstract, although in the description it includes this summary:

This invention relates to a universal bushing for beer barrels.

Barrels which are to contain beer have bung holes through which the barrel is filled. The beer is pumped or otherwise tapped from the barrel. It is common to provide at the bung hole of the barrel a bushing, of metal. Many and different types of bushings are used with which are associated plugs and/or valves for sealing the barrel against escape of the beer and with which a tapping mechanism may be used to withdraw the beer from the barrel.

There are several systems of tapping the beer from the barrel with each of which special plugs or valves for the different systems are used and heretofore it has been necessary, with a particular type of bushing used, to use with it a particular valve or plug designed to fit the bushing or be used therewith or integrally connected thereto. With my invention I provide a universal bushing capable of being sealed against escape of the beer and with which any of the different regular makes of plugs or valves may be used.