Rivet with a serrated pin and an annular locking member

Claim 1

A RIVET COMPRISING A TUBULAR BODY MEMBER ADAPTED TO PROJECT THROUGH THE OPENING IN A STRUCTURE TO BE RIVETED AND HAVING A PREFORMED HEAD AT ONE END WHICH IS PROVIDED WITH A CENTRAL, AXIALLY EXTENDING APERTURE TERMINATING IN AN ENLARGED GENERALLY RADIALLY OUTWARDLY INCLINED OPENING IN SAID PERFORMED HEAD, A PIN EXTENDING THROUGH SAID APERTURE IN SAID BODY MEMBER, A FIRST GROUP OF SERRATIONS FORMED IN SAID PIN AND EXTENDING RADIALLY OUTWARDLY BEYOND THE SURFACE OF SAID PIN IMMEDIATELY ADJACENT THERETO AND DEFINING AN OUTSIDE DIAMETER GREATER THAN THE DIAMETER OF SAID APERTURE IN SAID TUBULAR BODY MEMBER, SAID FIRST GROUP OF SERRATIONS EXTENDING PARALLEL TO THE LONGITUDINAL AXIS OF SAID PIN AND BEING ENGAGEABLE WITH SAID BODY MEMBER AT A POINT AXIALLY SPACED FROM SAID PREFORMED HEAD, A SECOND GROUP OF SERRATIONS FORMED IN A STRAIGHT CYLINDRICAL PORTION IN THE SURFACE OF SAID PIN AND LYING IN PLANES INTERSECTING THE LONGITUDINAL AXIS OF SAID PIN WITH THE INCLUDED ANGLE BETWEEN SAID PLANES AND THE LONGITUDINAL AXIS BEING AN ACUTE ANGLE SUBSTANTIALLY LESS THAN NINETY DEGRESS AND WITH SAID SECOND GROUP OF SERRATION LOCATED AT A POINT WITHIN SAID ENLARGED OPENING IN SAID PRE-