Blind rivet with setting pin having successively deeper locking grooves

Claim 1

A BLIND RIVET ADAPTED TO BE INSERTED FROM THE TOP SIDE AND SET IN THE ALIGNED APERTURES IN A PLURALITY OF WORK PIECES, COMPRISING: A TUBULAR SLEEVE INCLUDING A SHANK HAVING A RADIALLY ENLARGED HEAD AT ONE END PROVIDED WITH A LOCKING CROWN PROJECTING AXIALLY IN A DIRECTION OPPOSITE SAID SHANK, SAID LOCKING CROWN BEING ADAPTED TO BUCKLE INWARDLY WHEN THE AXIAL COMPRESSIVE FORCE THEREIN REACHES A PREDETERMINED LEVEL, THERE BEING A PLURALITY OF ANGULARLY SPACED AND LONGITUDINALLY EXTENDING WEAKENED SECTIONS IN SAID SHANK TO PERMIT LATERAL EXPANSION OF SAID SHANK AND SPLITTING APART OF THE SAME AT SAID WEAKENED SECTIONS UPON AXIAL COMPRESSION THEREOF; A PIN INCLUDING A STEM INITIALLY DISPOSED WITHIN SAID SLEEVE AND A PULLING SECTION PROJECTING EXTERIORLY OF THE HEADED END OF SAID SLEEVE, SAID STEM BEING FORMED WITH A PLURALITY OF LOCKING GROOVES ONE OF WHICH IS LONGITUDINALLY ALIGNED WITH SAID LOCKING CROWN TO RECEIVE SAID LOCKING CROWN WHEN THE LATTER IS BUCKLED INWARDLY TO LOCK SAID SLEEVE AND PIN TOGETHER, ANOTHER ONE OF SAID GROOVES BEING LONGITUDINALLY ALIGNED SUBSTANTIALLY FLUSH WITH THE TOP SIDE OF SAID HEAD TO FRACTURE AFTER SAID CROWN BUCKLES INWARDLY, SAID PIN HAVING ALL PORTIONS THEREOF FROM AND INCLUDING SAID PULLING SECTION TO A SAID GROOVE NEAREST SAID PULLING SECTION OF A GREATER CROSS SECTION THAN AT ANY OF SAID GROOVES WHEREBY FRACTURE WILL TAKEN PLACE AT ONE OF SAID GROOVES, SAID GROOVES BEING SUCCESSIVELY DEEPER COMMENCING WITH THE GROOVE NEAREST SAID PULLING SECTION AND PROCEEDING TOWARD THE OPPOSITE END OF SAID STEM, WHEREBY SAID PIN FRACTURES AT THE ONE OF SAID GROOVES LOCATED SUBSTANTIALLY FLUSH WITH THE TOP SIDE OF SAID HEAD WHEN THE TENSION FORCE IN SAID PIN EXCEEDS THE COMPRESSIVE FORCE REQUIRED TO SO BUCKLE SAID CROWN; AND MEANS ON SAID STEM AND SAID SHANK FOR TRANSMITTING A LONGITUDINAL COMPRESSIVE FORCE TO SAID SLEEVE AT THE END OF SAID SHANK OPPISITE SAID HEAD RESPONSIVE TO AN AXIAL PULLING FORCE BEING APPLIED TO SAID PULLING SECTION AND AN OPPOSITE REACTIVE FORCE BEING APPLIED TO SAID LOCKING CROWN.