Today in 1962, US Patent 3056436 A was issued, an invention of Paul R. Fechheimer and Warren H. Harlan, assigned to the Cherry Burrell Corp., for their “Filling Head for Filling Machines.” There’s no Abstract, although in the description it includes this summary:

A principal object of the invention is the provision of a filling spout structure having a retractable filling stem adapted, upon the presentation of a container to be filled to the filling spout structure, to enter the container and assume a lowermost position in which the bottom or free end of the stem lies in close proximity to the bottom of the container being filled, whereupon as the liquid product is introduced into the container the filling stem will automatically retract.

A further object of the invention is the provision of a retractable filling stem of the character described which coacts with a vacuum tube forming a part of the filling spout structure, the vacuum tube serving to establish a predetermined height of fill for the container.

A further object of the invention is the provision of a filling spout structure having a retractable filling stem adapted to be locked in retracted position, the filling spout structure incorporating means responsive to the presentation of a container thereto for releasing the locking means so as to permit the filling stem to enter the container there beneath.