Dome headed rivet, and workpiece assembly

Claim 1

In combination with a workpiece having a bore and a counterbore which is frusto-conical and tapers forwardly between a side of the workpiece and the bore, and toward the bore, (a) a rivet having an axially extending shank received in the workpiece and defining an axis, (b) the rivet including a head having an end face and a forwardly tapered frusto-conical section located forwardly of said end face, (c) the periphery of said head end face being substantially flush with the work surface, the end face forming a dome protruding axially in a rearward direction, said dome being generally ring-shaped and extending about said axis in substantially axial alignment with the outer surface of the shank, (d) the dome having an annular crest portion in axial alignment with said shank outer surface, and the dome radially outer extent which defines only about half of the dome being located in axially spaced relation to a forward taper defined by said forwardly tapered frusto-conical section, said dome crest portion being rearwardly convex in axial radial planes, (e) the head end face forming a concave central recess radially inwardly of said crest portion, the outermost annular extent of said recess located approximately in alignment with the outer surface of the shank.