Today in 1984, US Patent 4436228 A was issued, an invention of John A. Frey, assigned to Hoff-Stevens, Inc., for his “Keg Tapping Apparatus Having Improved Retainer.” Here’s the Abstract:

A keg tapping apparatus includes a keg unit secured within the neck of a keg by a retainer and a tavern unit coupled to the keg unit by the retainer. An operating handle opens valves associated with the keg unit to establish fluid communication between the keg and fluid inlet and outlet fittings on the tavern unit. The retainer has a body which includes a generally cylindrical bore and notches which communicate with the bore. Complementary inserts received within the notches are integrally attached to the body and define coupling lugs which project into the bore for coupling connection with the tavern unit. The inserts are made from a harder material than the body.