Today in 1985, US Patent EP 19840307773 was issued, an invention of Roger John Hyde, for his “Valved Closure for Kegs or Casks.” Here’s the Abstract:

A valved closure for a pressure vessel, such as a cask or keg (18). having a neck (22), for rigid attachment as a mounting ring to the mouth (24) of a tap hole (2) in the vessel and a valve-containing tubular body (10) inserted co-axially in the neck: has a rigid ring (30) engaging the tubular body and the keg neck, the ring being of malleable metal and having an inner periphery (33) shaped to engage the tubular body and a relatively thin outer peripheral skirt (32) shaped to be deformed, by a power tool, into fitting engagement about the neck rim (34), to provide securing means for preventing unauthorised axial removal of the valved closure, the so formed securing collar being accessible by a tool to cut the collar off the neck to release the valved closure: the securing collar may be split into two or more parts (29 and 31) to enable it to be fitted about a large diameter flange (15) at the top of the tubular body.