Today in 1935, US Patent 2018543 A was issued, an invention of William Buirk, for his “Beer Tapping Mechanism.” There’s no Abstract, although in the description it includes this summary:

The object of my invention is to provide a valve in the air line to the tap’ which is so constructed to permit closing of the air inlet and outlet ports; or to provide an uninterrupted free passage of air through the valve; or to provide a free passage of air through the valve with a safety valve in conjunction therewith to relieve any excess pressure from being applied to the contents of the barrel; or to provide closing of the inlet port and maintaining a limited pressure on the contents of the-barrel; or to provide closing of the inlet and safety valve ports and forming an open connection between the outlet port and a port exposed to the atmosphere to permit venting of the barrel when so desired. A further object is to provide means for disconnecting the air line from the valve whereby a suitable water thief can be attached thereto to make connection with the dispensing faucet for applying pressure to the liquid in the coil through the dispensing faucet.