Today in 1893, US Patent 498657 A was issued, an invention of Harvey P. Jacoby, for his “Beer Tap.” There’s no Abstract, though it’s described this way in the application:
This invention relates to taps or fittings which are inserted in the heads of beer kegs to receive the faucets through which the beer is drawn. A beer tap usually comprises a tubular shank, which is driven into the head of the keg, and a socket in the outer portion of the shank for the reception of the ordinary faucet. The tap is provided with some means for preventing the escape of the beer before the faucet is inserted, the common means being a cork or plug driven into the tap and adapted to be forced inwardly into the barrel, to permit the beer to flow into the faucet when the latter is inserted. In some instances the tap has been provided with a valve at the inner end of the faucet socket, said valve being arranged to yield to the faucet when the latter is inserted, the valve being held closed until the insertion of the faucet.