Today in 1905, US Patent 795237 A was issued, an invention of Henry Schmidt, for his “Bung.” There’s no Abstract, although in the description it includes these claims:

This invention relates to new and useful improvements in bungs especially designed for use in connection with beer-kegs, beer-barrels, and similar vessels or packages; and it consists in the construction and arrangement of parts hereinafter fully set forth, and point ed out particularly in the claims.

The object of the invention is to provide simple and efficient means for closing the bung-hole or the aperture through the bung bushing in a manner to prevent the escape of the contents, to protect the rubber or other compressible washer from the deleterious action of the beer or similar liquid, and to enable the bung to be quickly and easily removed and readily replaced, the same bung being adaptable for use many times.