Fastener means including an interior expansible core

Claim 1

A fastener for abutted members having registering apertures, comprising a tubular casing having a generally cylindrical section with heads at opposite ends thereof, said casing having an internal cylindrical chamber; a core filling said chamber and comprising a thermosetting resin plastic material which expands when heated and which retains its expanded condition when cooled, and a metal substance distributed throughout the core to increase thermal conductivity to facilitate setting of the resin plastic when heat is applied, and to increase rigidity of the core when the resin plastic material sets, said casing being made of a pliable resin plastic material to deform at one end thereon when the core expands and to retain its deformation due to the expanded condition of the core, the material of said casing being less thermally conductive than said core and having a lower coefficient of thermal expansion so that the core expands the casing when heated, one of the heads at one end of the casing having a diameter not greater than that of said cylindrical section to pass through said registering apertures in said members, the other one of said heads having a maximum diameter greater than that of said section to bear on one of said members while an expanded portion of said section at said one head engages the other one of said members; and a thermally conductive plug set in said other head and exposed thereat to conduct heat to the core from an external source applied to the plug to set and expand the core.