Today in 1971, US Patent 3596810 A was issued, an invention of Roy A. Taubenheim, for his “Keg-Tapping System.” Here’s the Abstract:

A beer keg-tapping device which consists of a keg unit that is permanently attached to the keg and a coupler unit detachably connected to the keg unit. Both units have liquid and gas passages which communicate when the units are coupled; a single valve element automatically closes both passages of the keg unit when units are not coupled. During coupling the passages of the two units are connected before the valve element is unseated, so that coupling is accomplished without spraying of beer.