Self-plugging blind rivet

Claim 1

A self-plugging blind rivet comprising an elongate stem and a tubular rivet body, the body having an elongate shank, a radial enlargement providing a rivet head at one end of the shank, a tail-end at the other end of the shank, and a bore extending axially through the rivet head and shank to the tail end, the stem extending through the bore of the body and comprising a stem-tail which projects from the head end of the body, and a plug connected to the stem-tail, the plug having a generally cylindrical first part adjacent to the stem-tail, a second part which is spaced from the stem-tail by the first part, and a radially enlarged terminal head at the end of the stem remote from the stem-tail, wherein the second part has a maximum diameter not greater than the diameter of the cylindrical first part, and the diameter of the plug is reduced progressively in the second part in the direction towards the terminal head, the second part having an initial reduction in diameter adjacent to the cylindrical first part, and an abrupt further reduction in diameter at a position spaced from the first part and from the underhead surface, said abrupt further reduction providing an abutment which faces towards the terminal head and an annular groove between the said abutment and the underhead surface, the terminal head presenting an underhead surface which faces towards the stem-tail for abutting the tail-end of the shank, the shank of the body having a main portion adjacent to the rivet head and an end portion spaced from the rivet head by the main portion, wherein the external and internal diameters of the end portion of the shank reduce progressively in the direction towards the tail-end over an axial length greater than the width of the annular groove, and the end portion has a radially inwardly extending part adjacent the tail-end of the shank, which part extends into the annular groove.