Slip-in fastening element for joining together two parts so that they may be undone

Claim 1

In an expandable locking fastening element for joining together first and second structural members, said fastening element being of the type including first and second generally parallel legs having adjacent first and second ends, said two legs being joined together by hinge means so that they may be hinged about an axis which is at said first ends and which is generally normal to a direction of expansion of said fastening element for locking the same in position, a fixing screw for moving said legs apart and thus for causing such expansion, each said leg having at said second end thereof a hooked head adapted to be hooked onto a part of a lip at an edge of an opening in a first structural member to be joined, one of said legs having therein a sliding sleeve adapted to lock said fastening element in a desired position of adjustment along a hole in a second member to be joined and into which said fastening element is to be positioned, the improvement wherein: said hinge means comprises a c-shaped spring ring having jaws fitting into grooves formed in said first ends of said legs; said sliding sleeve comprises an internally threaded plug slidably extending through an opening in said first leg; said second leg has a support member; said fixing screw is threaded into said plug and has an inner end movable between a retracted position spaced from said support member, whereat said spring ring urges said legs toward each other, and an extended position abutting said support member, whereat said legs are forced apart against the action of said spring ring; and one of said legs has extending from said first end thereof a support member for supporting said first end of the other of said legs.