Orthodontic headgear release assembly

Safety-release tension-applying mechanism for operative interposition between an end of an orthodontic facebow and an adjacent end of a headstrap and the like for the facebow, said mechanism comprising

• a first mechanism part including an attaching portion having a convex circular surface expanse of revolution including a pair of spaced, generally opposing gripping-surface portions, and
• a second mechanism part including a infinitely changable tension-producing portion having a changable-geometry concave circular surface expanse of revolution including a pair of spaced, generally opposing gripping-surface portions which, through changes in geometry, are complementarily fittable against and releasably engagable with said gripping-surface portions in said convex surface expanse of revolution in said attaching portion in said first part to assist in producing tension in an overall assembly including the release mechanism, headstrap and facebow, said tension-producing portion, when so engaged with said attaching portion, automatically releasing therefrom along a release axis, through changes occurring in its geometry, on the tension transmitted through such an assembly exceeding a predetermined tension level, said two pairs of gripping-surface portions, when engaged, accommodating sliding-contact pivoting about an axis substantially normal to said release axis.