Lockbolt construction including swaged nut

Claim 1

A FASTENER FOR SECURING A PLURALITY OF WORKPIECES COMPRISING: A PIN AND A TUBULAR COLLAR SWAGGED ONTO SAID PIN, SAID PIN INCLUDING A SHANK DISPOSED IN ALIGNED OPENINGS THROUGH THE PLURALITY OF WORKPIECES AND TERMINATING AT ONE END IN AN ENLARGED HEAD WHICH ENGAGES ONE SIDE OF THE WORKPIECES, SAID SHANK HAVING A PINTAIL PORTION AT THE END OPPOSITE FROM SAID HEAD AND LOCATED ON THE OPPOSITE SIDE OF THE WORKPIECES AND ADAPTED TO BE ENGAGED BY A TOOL FOR SETTING SAID FASTENER, A BREAKNECK GROOVE CONNECTING SAID PINTAIL PORTION TO THE REMAINDER OF SAID SHANK AND BEING OF A REDUCED SECTION RELATIVE TO THE OTHER PORTIONS OF SAID SHANK, AN INTERMEDIATE PORTION LOCATED BETWEEN SAID HEAD AND SAID BREAKNECK GROOVE AND BEING THREADED OVER AT LEAST A PART OF ITS SURFACE WITH THE THREADS EXTENDING UP TO SAID BREAKNECK GROOVE, SAID COLLAR BEING DEFORMED COMPLETELY CIRCUMFERENTIALLY OVER SUBSTANTIALLY ITS ENTIRE LENGTH INTO SAID THREADED PART WITH COMPLEMENTARY THREADS BEING FORMED IN SAID INTERNAL SURFACE AND WITH A PLURALITY OF CLOSELY, CIRCUMFERENTIALLY SPACED, AXIALLY EXTENDING RIDGES AND GENERALLY V-SHAPED GROOVES BEING FORMED IN SAID EXTERNAL SURFACE OVER SUBSTANTIALLY ITS ENTIRE LENGTH, WITH SAID RIDGES AND GROOVES ADAPTED TO BE GRIPPED BY A WRENCH, A PLURALITY OF CIRCUMFERNTIALLY DISPOSED, AXIALLY EXTENDING DISCONTINUITIES CORRESPONDING TO THE NUMBER OF SAID GROOVES DEFINED ON SAID INTERNAL SURFACE BY THE MATERIAL OF SAID INTERNAL SURFACE IN RADIAL ALIGNMENT WITH SAID GROOVES EXTENDING RADIALLY INWARDLY INTO THE THREADS OF SAID THREADED PART TO AN EXTENT GREATER THAN THE MATERIAL OF SAID INTERNAL SURFACE IN RADIAL ALIGNMENT WITH SAID RIDGES, SAID COMPLEMENTARY THREADS GRIPPIGN SAID THREADS OF SAID INTERMEDIATE PORTION WITH THE FORCE PRODUCED BY SWAGING SAID COLLAR INTO SAID INTERMEDIATE PORTION WHILE FORMING SAID RIDGES, GROOVES AND DISCONTINUITIES, SAID COLLAR INCLUDING MEANS AT ONE END FOR HOLDING OFF THE TOOL FROM SWAGING SAID COLLAR UNTIL A SELECTED TENSILE LOAD IS APPLIED TO THE WORKPIECES BETWEEN SAID COLLAR AND SAID HEAD, SAID PINTAIL BEING SEVERABLE FROM SAID SHANK AT SAID BREAKNECK GROOVE AFTER SAID COLLAR IS SET ON SAID PIN AT A TENSILE FORCE GREATER THAN SAID SELECTED FORCE AND WITH SAID COLLAR BEING THREADABLY REMOVABLE FROM SAID PIN BY MEANS OF A WRENCH ADAPTED TO ENGAGE SAID RIDGES AND GROOVES.