Today in 1966, US Patent 3228413 A was issued, an invention of Frederick F. Stevens Jr., for a “Keg Tapping Device.” There’s no Abstract, but there’s this from the description:

The general object of this invention is to provide an improved device for tapping kegs or similar containers, the device being relatively inexpensive to manufacture, easy and safe to use, and sanitary.

A more particular object of this invention is to provide a tapping device which eliminates any danger of parts being blown from the device during the attachment of the device or a part thereof to a keg.

Another object of this invention is to provide a tapping device which is usable with conventional kegs, of the type having cylindrical sleeves defining the tapping openings, without any modification of the kegs. In keeping with this object, a further object is to provide a tapping device which is usable with kegs having cylindrical tapping opening-deiining sleeves of various axial lengths.

A further object of this invention is to provide a tapping device which does not require a cylindrical sleeve or other complicated keg structure at the tapping opening and which may be used with a simplified keg, of lower cost than present conventional kegs, having a tapping opening consisting of nothing more than a simple round opening passing through a flat Wall of the keg.

A still further object of this invention is to provide a tapping device of the foregoing character which consists of one part or sub-assembly, called the keg unit, adapted to be permanently, or at least semi-permanently, attached to a keg so as to remain with the keg through a number of fillings and emptyings of the keg, and another part or sub-assembly, called the tavern unit, which is adapted 3,228,413 Patented Jan.. 11, 1966 to be attached to the cooling and drawing equipment at a tavern and which remains at the tavern.

Another object of this invention is to provide a keg unit for a tapping device as set forth in the preceding paragraph, which keg unit replaces the plug conventionally used in the tapping opening during shipment of the keg and which is completely leakproof so as to avoid any danger of the beer going flat because of loss of pressure.

Another object of this invention is to provide a tapping device including a safety means for automatically bleeding air from the associated keg to maintain the pressure in the keg at a safe level in the event the pressure tends to rise above such level. In keeping with this object, a further object of the invention is to provide a tapping device wherein excess pressure may be manually bled from the keg without uncoupling any part of the device from the keg and without loss of beer.

A further object of this invention is to provide a novel method of assemblying a keg unit of the foregoing character with a keg whereby an improved and safe mounting of the unit to the keg is obtained together with maximum utilization of the space provided by the tapping opening.

Still another object of this invention is to provide a keg having combined therewith in a permanent or semi-permanent manner a tapping unit designed for cooperation with a complementary unit at the point of use, the tapping unit being joined to the keg in an improved manner providing simplicity of construction, strength and safety, among other benefits.