Today in 1897, US Patent 575545 A was issued, an invention of Peter E. Dunn and William H. Partridge, for their “Air and Beer Connection for Beer-Casks.” There’s no Abstract, although in the description it includes this summary:

This invention relates to devices for hermetically closing the outlets or inlets to beer casks and to attachments for said devices for controlling the discharge of beer therefrom, and to a system of gage and pump connections attached to said devices, the object being to provide devices of improved construction for closing beer-cask openings for transportation and for connection with said openings for operating the devices thereof and for governing the discharge of beer from said casks and the introduction of air-pressure thereto; and the invention consists in the peculiar construction of said devices, apparatus, and connections, all as fully described, and. more particularly pointed out in the claim.