Tension stressed structure

Claim 1

An assembled joint including a plurality of overlying members having aligned openings therein, an improved multi-part tension stressed fastening means joining said members together comprising a pin, a bushing and a nut, said pin having a shank extending through said openings with the shank projecting beyond the outer surface of one of said members, means holding the pin against movement through sAid openings in the direction of said last named outer surface, the projecting end of the pin having a grooved portion, the outer end of the grooved portion being threaded, a bushing disposed over said grooved portion, a nut threaded on said threaded portion abutting said bushing, said bushing being of a softer material than said nut, said bushing being crimped radially inwardly to form and as formed having a plurality of permanent radially inwardly extending, circumferentially spaced indentations in the radially outer surface of said bushing with the material from said indentations of said bushing having been deformed into contact with the underlying grooved portion and to effect an elongation of the bushing axially of the pin against the abutting face of said nut to thereby impart a residual tension in said pin, said nut having serrated-like irregularities extending at least partially radially in the face abutting said bushing and said grooved portion in said pin under said bushing having longitudinally extending serrations formed therein, said bushing engaging said irregularities and said serrations whereby an interlock is effected between said nut, said bushing and said pin.