Hollow wall screw anchor

A screw anchor for installation in a hole drilled in a hollow wall, said anchor being molded of synthetic plastic material and comprising:

• A. a shank constituted by a pair of front legs and a pair of rear legs in a diamond-like configuration, said front legs being hinged together by a front apex living hinge having an opening therein, said front legs being joined to said rear legs by side apex living hinges, the ends of said rear legs defining a rear apex;
• B. a socket attached to said shank adjacent said rear apex by a pair of normally outstretched resilient webs that merge with said rear legs, said webs having a memory resulting in the return of the webs to their normal state when the webs are flexed and thereafter released, whereby when said diamond-like shank is compressed at said side apex hinges, it is transformed into a tongue which is insertable in said hole, making it possible to seat said socket therein;
• said tongue, after passing through the hole, then being caused by the webs to resume its diamond-like configuration, said webs having a length permitting hinging thereof adjacent the inner surface of said hollow wall at a point determined by the length of the socket relative to the thickness of said hollow wall, said socket having a bore in registration with said front apex opening;
• and
• C. a screw which is turnable into said bore and is threadably engaged thereby, the turning screw then advancing to engage the ends of said rear legs and to spread them apart to transform the shank into a truss whose bottom chord is formed by said rear legs and is pressed against the inner surface of said wall to prevent removal of said anchor, the point of said advancing screw then entering and threadably engaging the opening in the front apex hinge to define a central strut between the front apex of the truss and the socket, whereby the truss may be collapsed by withdrawal of the screw to permit removal of the anchor from the hole.