Combination thread swaging and fastening screws

Claim 1

A COMBINATION THREAD-SWAGING AND FSTENING SCREW COMPRISING AN ELONGATED SHANK INCLUDING A GENERALLY CYLINDRICAL REAR BODY PORTION AND A GENERALLY FRUSTO-CONICAL FORWARDLY TAPERED FRONT PILOT END PORTION, A CONFINUOUS THREAD CARRIED ON SAID SHANK AND INCLUDING BOTH A PLURALITY OF HELICAL TURNS ON SAID REAR BODY PORTION AND A PLURALITY OF HELICAL TURNS ON SAID FRONT PILOT END PORTION, SAID THREAD HAVING A FIXED PITCH, THE TURNS ON SAID REAR BODY PORTION HAVING SUBSTANTIALLY THE SAME MINOR RADIUS AND SUCCESSIVELY FORWARD ONES OF THE TURNS ON SAID FRONT PILOT END PORTION HAVING GRADUALLY REDUCED MINOR RADII, THE TURNS ON SAID REAR BODY PORTION HAVING A FIRST FIXED CREST PROJECTION FROM THE ROOT THEREOF AND THE TURNS ON SAID FRONT PILOT END PORTION HAVING A SECOND FIXED CREST PROJECTION FROM THE ROOT THEREOF, WHEREIN SAID FIRST FIXED CREST PROJECTION IS GREATER THAN SAID SECOND FIXED CREST PROJECTION, AND A PLURALITY OF SEPARATE AND DISTINCT THREAD-SWAGING LOBES CARRIED ENTIRELY BY THE TURNS ON SAID FRONT PILOT END PORTION ALONG THE HELIX OF SAID THREAD WITH A ROTATIONAL ANGLE A ABOUT THE LONGITUDINAL AXIS OF SAID SHANK BETWEEN THE CENTERS OF ADJACENT ONES OF SAID LOBES, WHERE A=360* + B AND WHEREIN B IS A FIXED ANGLE WITHIN THE APPROXIMATE RANGE 60* TO 120*, EACH OF SAID LOBES SUBTENDING A ROTATIONAL ANGLE C ABOUT THE LONGITUDINAL AXIS OF SAID SHANK, WHEREIN C IS A GIVEN ANGLE WITHIN THE APPROXIMATE RANGE 60* TO 120*, EACH OF SAID LOBES INCLUDING A CREST PROVIDED WITH LEADING AND TRAILING FACES, THE LEADING AND TRAILING EDGES OF EACH OF SAID LOBE CREST RESPECTIVELY MERGING INTO THE ADJACENT PORTIONS OF THE CREST OF THE ASSOCIATED TURN ON SAID FRONT PILOT END PORTION, THE LEADING AND TRAILING FACES OF EACH OF SAID LOBE FLANKS RESPECTIVELY MERGING INTO THE ADJACENT PORTIONS OF THE FLANK OF THE ASSOCIATED TURN ON SAID FRONT PILOT END PORTION, EACH OF SAID LOBES HAVING A VARIABLE CREST PROJECTION FROM THE ROOT THEREOF THAT IS MAXIMUM WUBSTANTIALLY AT THE CENTER THEREOF THAT AT ITS MAXIMUM VALUE IS SUBSTANTIALLY GREATER THAN SAIS SECOND FIXED CREST PRJECTION OF THE ASSOCIATED TURN ON SAID FRONT PILOT END PORTION AND EACH OF SAID LOBES HAVING A VARIABLE FLANK WIDTH AT THE ROOT THEREOF THAT IS MAXIMIZED SUBSTANTIALLY AT THE CENTER THEREOF AND THAT AT ITS MAXIMUM VALUE IS SUBSTANTIALLY GREATER THAN THE FLANK WIDTH OF THE ASSOCIATED TURN ON SAID FRONT PILOT END PORTION, THE MAXIMUM CREST PROJECTION OF THE REARMOST OF SAID LOBES ON SAID FRONT PILOT END PORTION BEING SUBSTANTIALLY EQUAL TO SAID FRIST FIXED CREST PRJECTTION OF THE TURNS ON SAID REAR BODY PORION AND THE MAXIMUM FLANK WIDTH OF THE REARMOST OF SAID LOBES ON SAID FRONT PLOT END PORTION BEING SUBSTANTIALLY EQUAL TO THE FLANK WIDTH OF THE TURNS ON SAID REAR BODY PORTION.