Self-centering dental face-bow

Claim 1

A self-centering dental face-bow comprising in combination an elongated cross-bar adapted to be disposed across the front of a dental patient's face in spaced relationship therewith, a mount which is adapted to receive various dental appliances which are to be engaged by a patient's mouth, said mount being disposed generally centrally on said cross-bar, a pair of spaced arms extending transversely from said cross-bar for disposition along associated sides of a patient's head in spaced relationship therewith and being movable toward and away from each other in the direction of length of said cross-bar, means disposed on each of said arms for engaging an associated side of a patient's head, means incorporated with said cross-bar for adjustably moving said arms toward and away from each other equidistantly in relation to said mount thereby to adjust the spacing between said arms and maintain said mount in said generally central disposition, said cross-bar being a tube, each of said arms including a tubular portion extending coaxially with said cross-bar tube, said tubular portions being slidably received within an associated end of said cross-bar tube, said adjustably moving means including a rotatable shaft extending coaxially through said cross-bar tube and said tubular portions and being relatively rotatable thereto, said shaft having right hand threads at one end thereof for threadingly engaging one of said arms and left hand threads at another end thereof for threadingly engaging the other of said arms, whereby upon rotation of said shaft said tubular portions of said arms move slidably toward and away from each other, said cross-bar and shaft include cooperative means for precluding axial movement of said shaft relative to said cross-bar and, said cooperative means includes an inwardly directed tang disposed generally centrally within said cross-bar which relatively rotatably engages a circumferential indentation disposed generally centrally on said shaft.