Abstract: A self-retained fastener including locking means provided near the end of the fastener first inserted through a hole in a workpiece wherein the locking means becomes operative after passing beyond the hole in the workpiece. The locking means comprises an annular groove near the end of the fastener having a configuration which increases radially outwardly from a point axially inwardly from the end of the fastener toward the end of the fastener. A spring ferrule member is engaged about the end of the fastener around the annular groove and includes a portion thereof which cooperates with the exterior surface of the workpiece and the annular groove on the fastener to oppose unintentional removal of the fastener from the workpiece once it has passed through the hole in the workpiece. The ferrule also serves as a removal tool for permitting removal of the fastener when desired.

Abstract: A self-locking threaded fastener of the type having a resilient thermoplastic resin patch bonded to the thread surface and a method and apparatus for making such fasteners are disclosed. The fastener is heated to a temperature in excess of the plastic melting temperature by induction heating coils and powder is thereupon deposited on the surface of the threads over a predetermined area by gravity feed. Rolling pressure is then applied to the plastic material to form the patch, packing the material between the thread flanks and confining the height of the patch to a controlled radial height above the thread crests. The controlled radial height of the patch is within the normal envelope of the basic major diameter of the fastener thread.

Abstract: A self-locking threaded fastener of the type having a resilient thermoplastic resin patch bonded to the thread surface and a method and apparatus for making such fasteners are disclosed. The fastener is heated to a temperature in excess of the plastic melting temperature by induction heating coils and powder is thereupon deposited on the surface of the threads over a predetermined area by gravity feed. Rolling pressure is then applied to the plastic material to form the patch, packing the material between the thread flanks and confining the height of the patch to a controlled radial height above the thread crests. The controlled radial height of the patch is within the normal envelope of the basic major diameter of the fastener thread.

Abstract: A vibration resistant threaded fastener which may be a set screw or any other type of threaded fastener wherein the load bearing flank of the threaded surface of the screw is provided with a series of serrations. Each serration is formed with an inclined ramp terminating in a buttress with the ramp surface being inclined in the direction of tightening the fastener so that the buttress presents a surface tending to act against rotation of the fastener to preclude loosening of the fastener. Upon engagement in a workpiece under compressive load the buttress of the serrations coact with the thread flank of the mating internal thread in a workpiece to preclude disengagement of the fastener. In one embodiment of the fastener bearing pads are provided to limit the degree of coaction between the serrations and the thread flank of the workpiece.