William M. Gambill
The Gambill Articulator is a non-arcon, semi-adjustable instrument with condylar controls designed very much like the Hanau H 2; that is, the condylar balls are on the upper member and adjustable straight closed slots are on the lower member. There is provision for adjusting the progressive Bennett movement by turning the vertical condylar posts. The principle feature of this articulator is an incisal pin and guide milling device for "grinding-in" denture occlusion. This device consists of a revolving incisal pin with a horizontal cam that that revolves within a V-shaped trough incisal guide. The purpose of the horizontal cam on the incisal pin rotating within the V-shaped incisal guide is to provide combined vertical and oscillatory movements. There is no doubt that this feature would produce a bumping action. The rotary movement of the incisal pin is operated by a worm gear and pinion located in the upper member of the articulator. It is activated by means of a flexible twist shaft extending from the rear of the upper member to a power source. There is an anterior adjusting screw in the incisal guide trough to provide for "long centric."
Dr. Edgar N. Starcke's articles in the Journal of Prosthodontics have more information on the history of articulators.