Blind rivet assembly having mandrel with a deformable skirt portion

Claim 1

IN A BLIND RIVET ASSEMBLY, THE COMBINATION OF: A PIN HAVING A STEM ADJACENT ONE END THEREOF AND A SHANK ADJACENT THE OTHER END THEREOF, SAID SHANK HAVING A DIAMETER GREATER THAN THAT OF SAID STEM, SAID PIN HAVING AT THE JUNCTION OF SAID SHANK AND SAID STEM A TAPERED ANNULAR SHOULDER WHICH CONVERGES TOWARD SAID ONE END OF SAID PIN, SAID SHOULDER BEING PROVIDED THEREIN WITH AN ANNULAR RECESS HAVING AN OPEN END WHICH FACES AXIALLY OF SAID PIN TOWARD SAID ONE END THEREOF, SAID RECESS DIVERGING TOWARD SAID ONE END OF SAID PIN AND HAVING AN OUTER WALL WHICH COOPERATES WITH SAID SHOULDER TO PROVIDE SAID PIN WITH A TAPERED ANNULAR SKIRT CONVERGING TOWARD SAID ONE END OF SAID PIN, THE INSIDE DIAMETER OF SAID OPEN END OF SAID RECESS BEING SUBSTANTIALLY EQUAL TO THE DIAMETER OF SAID STEM, SAID RECESS HAVING AN INSIDE DIAMETER LESS THAN THE DIAMETER OF SAID STEM IN A ZONE SPACED AXIALLY FROM SAID OPEN END OF SAID RECESS TOWARD SAID OTHER END OF SAID PIN; AND A TUBULAR RIVET ON SAID STEM AND HAVING AT ONE END THEREOF A HEAD ADJACENT SAID ONE END OF SAID PIN AND AT THE OTHER END THEREOF A TAIL ADJACENT SAID SKIRT, THE INSIDE DIAMETER OF SAID TAIL BEING LESS THAN THE DIAMETER OF SAID SHANK, BUT AT LEAST EQUAL TO THE DIAMETER OF THE FREE END OF SAID SKIRT, AND SAID HEAD HAVING THEREIN AN INWARDLY FACING ANNULAR CAVITY TO RECEIVE SAID SKIRT WHEN SAID ASSEMBLY IS SET.