Today in 1993, US Patent 5248062 A was issued, an invention of Vincent G. Hillard, for his “Beer Keg Tap Apparatus.” Here’s the Abstract:

A tap member is arranged with a threaded lid directed into engagement with an upper end of the tap structure configured as a cylindrical housing, including a cavity receiving a compressed gas canister there within. Upon projection of the lid into the housing, the canister is pierced directing compressed gas from the canister into an underlying beer keg, whereupon beer is dispensed through a dispensing conduit.