Blind fastener

Claim 1

A BLIND BOLT ASSEMBLY INCLUDING: A SLEEVE MEMBER HAVING INTEGRAL HEAD, SHANK AND NUT PORTIONS; THE SHANK AND NUT PORTIONS BEING OF SUBSTANTIALLY UNIFORM EXTERNAL DIAMETER; A V-SHAPED EXTERNAL CIRCUMFERENTIAL GROOVE THINNING THE SLEEVE WALL INTERMEDIATE SAID NUT AND SHANK PORTIONS TO ITS SMALLEST CROSS-SECTIONAL AREA, SAID GROOVE BEING POSITIONED ON THE SLEEVE SO THAT WHEN INSTALLED IN A BLIND APPLICATION THE GROOVE WILL PROJECT BEYOND THE BLIND FACE OF THE WORKPIECE, THE SURFACE OF THE GROOVE THAT IS INTEGRAL WITH THE NUT BEING PROVIDED WITH AXIALLY EXTENDING KNURLS AND THE SIDES OF THE GROOVE FORMING DIVERGENTLY OPPOSED INCLUDED ANGLES OF ABOUT 30* WITH THE LONGITUDINAL AXIS OF THE FASTENER; A BORE EXTENDING AXIALLY THROUGH SAID HEAD AND SHANK PORTIONS AND INTO THE NUT PORTION; THE BORE HAVING A SLIGHT COAXIAL COUNTERBORE IN THE REGION OF SAID HEAD AND SHANK PORTIONS AND BEING INTERNALLY THREADED IN THE REGION OF SAID NUT PORTION; SAID ASSEMBLY HAVING MEANS FOR RESTRAINING ROTATION OF THE SLEEVE ABOUT THE AXIS OF THE SLEEVE BORE; A CORE BOLT HAVING A HEAD, SAID HEAD HAVING A TOOL RECEIVING DRIVING SURFACE FOR THE APPLICATION OF TORQUING FORCES THERETO, SAID BOLT HAVING AN ELONGATED SHANK DIMENSIONED FOR INSERTION INTO THE BORE OF SAID SLEEVE MEMBER FROM THE HEAD END THEREOF AND HAVING AN EXTERNALLY THREADED END PORTION FOR ENGAGEMENT WITH THE THREADS IN THE NUT PORTION OF THE SLEEVE, SAID ASSEMBLY BEING ADAPTED TO EFFECT SEPARATION AND SWAGING OF SAID NUT PORTION FROM AND OVER THE SHANK OF SAID SLEEVE MEMBER UPON THE TRANSMISSION OF TORQUING FORCES TO THE NUT FROM THE CORE BOLT.