Insert with angular flange lock

Claim 1

A ONE-PIECE FASTENER, COMPRISING: A CYLINDRICAL BODY; AN INTEGRAL DEFORMABLE FLANGE PROJECTING RADIALLY OUTWARDLY THEREFROM, SAID FLANGE BEING INCLINED ON A RELATIVELY SMALL ANGLE WITH RESPECT TO A PLANE PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID BODY, THE OUTERMOST SURFACE OF SAID FLANGE BEING AN INTERRUPTED PLANAR SURFACE; EXTERNAL THREADS EXTENDING FROM ONE END OF SAID BODY TOWARD SAID FLANGE; A SMOOTH PORTION PROVIDED BY SAID BODY EXTENDING BETWEEN SAID EXTERNAL THREADS AND SAID FLANGE, SAID SMOOTH PORTION HAVING A DIAMETER NOT EXCEEDING THE ROOT DIAMETER OF THE EXTERNAL THREADS WHEREBY THE FASTENER MAY BE FULLY SCREWED INTO THE THREADED BORE; A WEAKENED PORTION PROVIDED BY SAID FLANGE ON THE UNDERSIDE THEREOF POSITIONED ADJACENT SAID SMOOTH PORTION WHEREBY THE FLANGE MAY BE DEFORMED TO A POSITION PREDETERMINED TO THE BODY AXIS; A PLURALITY OF RADIAL SERRATIONS CARRIED BY THE UNDERSIDE OF SAID FLANGE NEAR THE PERIPHERY THEREOF, SAID SERRATIONS HAVING THE ROOTS THEREOF INCLINED OUTWARDLY AWAY FROM THE EDGE OF SAID WEAKENED SECTION ON AN ANGLE WITH RESPECT TO A PLANE PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID BODY, THE ANGLE OF INCLINATION OF SAID INCLINED SERRATIONS PERMITTING THE OUTER EDGES THEREOF TO SEAT SUBSTANTIALLY FLUSH OPEN THE BEVELED PORTION OF THE COUNTERBORE IN THE WORKPIECE WHEREBY UPON THE APPLICATION OF AN AXIAL FORCE THE WORKPIECE MATERIAL IS CAUSED TO FLOW INTO THE SERRATION ROOTS, THEREBY LOCKING THE FASTENER AGAINST ROTATION RELATIVE TO SAID WORKPIECE.