Patent GB-326967-A (GB)
Title: Improvements in articulators
IPC: A61C11/02
Filed: 1929-02-22
Abstract: 326,967. Hagman, H. C. Feb. 22, 1929. Teeth, artificial.- -The upper jaw model of an articulator is hung from a hinged support so that it can oscillate about a plurality of horizontal axes passing through the centre of a sphere whose surface conforms to the surface of occlusion of the jaw models. An arcuate plate 19 is connected to an upright 10 with two feet 23 which, together with the foot 20, support the device. The upright 10 and an arm 12 are pivoted together by a leaf hinge, on a pintle 27 corresponding to the condyles of the jaw, and the arm 12 can be swung back until the shoulders 30, 31 abut against each other. With the arm 12 in its upright position, shoulders 28, 29 abut against each other, and, in its lowered position, a foot 32 bears on the work table and holds the device in equilibrium. A set-screw 74, when adjusted, engages the middle leaf of the hinge and prevents relative movement of the arm 12. Thumb-screws 33, 34, 35, 36 passing through the plate 19 support the lower jaw model which is clamped between jaws 38, 39 slidable in grooves in the plate 19 and moved by a combined right and left screw 44 passing through threaded depending portions on the jaws and also through a depending rib connecting the two parts of the plate 19. A thumb-screw 145 on the lug 46 assists in holding the model in position. The arm 12 supports an universal joint comprising a socket 14 containing a ball 17, Fig. 2, with a stem 18, the stem passing through a circular opening in the socket. This opening permits the stem to oscillate in all directions through given limits, whilst an arcuate slot 49 in the socket 14 joined to the circular opening, permits the stem to swing to a horizontal position. A cap 50 threaded into the socket and held by a lock-nut 53 is formed with a spherical surface to hold the ball seated in the socket. Swinging movements of the ball 17 are resisted by a smaller ball 55 which moves in a vertical guideway in the cap 50 and is pressed by a spring 57 into a conical depression 54 in the ball 17. To hold the stem 18 rigid. a screw 58 is turned to bear down upon the ball 55 and deprive it of upward movement; and to permit the stem to swing only in the slot 49, a screw 158 is turned until it is seated in a conical cavity 60 in the ball 17. A support E for an upper plate model carries a tubular sleeve 63 which can slide on the stem 18 and which is provided with a thumb-screw 64 with a conical point to engage in a V-shaped groove 65 in the stem 18, whereby the support is held in position and rotational movement of the support about the stem is prevented. The arrangements for clamping a model on the support E are similar to those on the plate 19 except that only three thumb-screws pass through the plate instead of four. Reference marks 88 and an index mark 89 are provided on the ball 17 and socket 14 respectively, and reference marks 84 provided on the stem 18 permit of accurate replacement of the upper support. The support E may be replaced by an adjustable mounting plate, Fig. 4, which consists of a sleeve 69 and sea-screw 70, and a disc 71 whose surface coincides with the surface of an imaginary sphere with centre at the centre of the ball of the universal joint. Methods of using the device are described.