Today in 1971, US Patent 3563424 A was issued, an invention of Mack S. Johnston, for his “Beer Tap.” There’s no Abstract, but the application states that his “invention relates to a beer-tapping device and especially to an improved adapter for attachment in the beer outlet of a standard keg. It comprises a metallically enclosed, readily assembled unit, insertable from outside the keg with a laterally offset liquid passageway through the adapter. The offset passage takes optimum advantage of the limited space available while, at the same time, the unit is compatible with existing systems. Also disclosed is a novel metallic locking unit for separating the beer and gas passageways in the adapter as well as a novel flexible resilient check valve for the gas passage through the adapter.”