Screw anchoring bushing for use in semihard materials

Abstract From the Canadian patent

A screw anchoring plug or bushing for use in predrilled mount ing holes in elements of semihard materials such as chipboard consisting of a sleeve made as a rolled up piece of metal sheet material provided with a number of slightly projecting barb-like tongue portions and cured to be resilient whereby, the tongue portions project as leaf springs. The sleeve is threaded for direct engagement with a standard screw and when, it is inserted in the mounting hole and the ends of the tongue portions are hereby caused to resiliently engage the wall of the hole, the sleeve will thereafter be moved axially outwardly when the screw is tightened, and the tongues will cut themselves into the hole wall …