In prior approaches to the formation of artificial animal jaws for use in taxidermy forms, it has been customary to design the jaw either in an open or closed mouth position. In either case, the upper and lower jaws are substantially fixed with respect to each other. This is not a significant disadvantage when a closed mouth position is desired; however, when an open mouth arrangement is preferred, the taxidermist often alters the standard head shell to provide the most pleasing result for the particular hide to be mounted. The degree of jaw opening, however, is limited to that provided in the standard manufactured jaw sets. In order to adjust the jaws to a different angle, the taxidermist must sever the upper and lower jaws, cut away or add portions to achieve the desired angle and hold the jaws in the correct position while applying glue or other bonding agent to maintain the selected angle for insertion into the head shell. Needless to say, this is time-consuming and frequently does not yield accurate and attractive results.
Representative of prior art approaches are U.S. Pat. Nos. 2,306,464 to M. Nowotny; 1,667,205 to G. F. Ingwersen; and 4,359,320 to D. E. Thomas. In the early Ingwersen patent, the upper and lower jaw members are immovably fixed together in an open position. The Nowotny patent discloses a set of artificial jaws in which the rear portions of the upper and lower jaws are formed with facing ribs which support the jaws in an open position, and rearwardly extending shoulders serve to anchor the jaws in the head shell. The jaws are inserted separately into the shell so that the ribs are in alignment, and the jaws are then bonded or otherwise fastened in place. The recent Thomas patent discloses a jaw set for a snake mount wherein the upper and lower jaws are formed with cooperating mating surfaces. The upper and lower jaws can be shaped in the manufacturing process so as to interlock at a particular opening angle, but are not capable of adjustment thereafter.
Another typical approach is to connect the upper and lower jaw members by means of a living hinge, which permits a certain range of independent movement of the jaws with respect to each other. This does not obviate the problem of adjusting the jaw members to a desired opening angle, as the jaws have a tendency to spring back to their original position as they are inserted into the mouth of the head shell.