Snap-on screw

Claim 1

A pair of fasteners which may be joined together, with each of the pair of fasteners shaped to individually fasten to one of a pair of members that are to be joined together by the engaged pair of fasteners, in which said fasteners are each formed with an external screw thread, in which a first unit of the pair of fasteners is formed with a cylindrical axial socket hole and a second unit of the pair of fasteners is formed with a cylindrical plug that extends axially from said second unit, said plug of a size to fit into the socket hole of the said first unit, in which the socket hole of the first unit is formed with a concentric recess of a size to engage a pivoted leaf member fitted to the side of the plug, and in which the plug is fitted with a concentric recess of a size to retain a pivoted leaf member, said leaf member being pivotally mounted in said plug recess, said plug fitted with spring means to bias the leaf member to extend out of said plug recess and away from the axis of the plug, said recess of the socket hole of the first unit shaped, in axial cross-section of the first unit, with a convex curved recess wall extending from the wall of the axial socket hole, as viewed from the center of rotation of the pivoted leaf member of the second unit, in the assembled state of the fasteners, said convex curved recess wall located so as to bear against an end of the leaf member in the assembled state of the fasteners, so that an axial force applied between the two units, in the direction of separating the two units, biases the leaf member against the spring means and biases the leaf member away from the recess of the socket hole so as to permit disengagement of the two assembled units.