Abstract: The present invention discloses a extrusion forming method and a forming apparatus for manufacturing a self-clinching rivet, wherein the forming method comprises: upset-extruding a first end of a wire blank to shape it into a material pushing portion and a shank portion billet, upset-extruding the shank portion billet to shape it into a shank portion and a groove portion, and upset-extruding a second end of the wire blank to create a slot portion and a slot shaft portion. The invention for manufacturing the self-clinching rivet by one-time extrusion forming does not generate waste during processing, which greatly improves a utilization rate of raw materials compared with the traditional machining method. Meanwhile, a formed piece manufactured by the present invention has complete metal streamlines, which can greatly improve its strength compared with the one manufactured by machining and avoid a risk of hydrogen embrittlement in a subsequent surface treatment.

Abstract: A method of manufacturing of an expansion sleeve including providing a sleeve blank having axially extending material weaknesses (9), and forming the longitudinal slots (5) by tearing open the material weaknesses (9) by substantially radially expanding same.

Abstract: A self-plugging blind rivet for securing together apertured members comprises a tubular shell (11) having a tail end fact (16) at one end, a pre-formed radially enlarged head (13) at the other end, and a stem which extends through the shell and has a stem head (22) adjacent the tail end fact (16) of the shell. The region adjacent the stem head (22) is of increased diameter relative to the rest of the stem shank and has a plurality of axial depressions (26) formed therein, the corresponding region of the shell being arranged to fill the axial depressions (16) in the stem and being harder than the material of the shell (11) in a region adjacent the radially enlarged head (13). In use and under axial compression leading of the shell (11), the shell (11) buckles in the region adjacent the member remote from the performed head to form a blind head in contact with said member so as to clamp together the apertured members.

Abstract: A blind rivet includes a mandrel shaft having a head disposed at one axial end. A hollow rivet shell has a cylindrical shape including an inner cylindrical surface and an outer cylindrical surface. The rivet shell surrounds the mandrel shaft. The outer cylindrical surface has at least one attenuation groove, which includes at least two recesses. Each recess has a bottom surface that substantially forms a secant with respect to the outer cylindrical surface. A method of manufacturing a blind rivet comprises the steps of placing a mandrel shaft having a head within a hollow rivet shell, producing at least one attenuation groove in an outer cylindrical surface of the rivet shell after the placing step so that at least two recesses are formed. Each of the recesses has a bottom surface that substantially forms a secant with respect to the outer cylindrical surface.

Abstract: A blind fastener which comprises a fastener body, a stem and a two-piece shear/expander assembly. The assembly includes an anchor section sized to fit within an annular groove in a neck portion of the stem and an expander collar which surrounds the shear ring. When the fastener is installed, a bulbing portion of the expander collar upsets the tail end of the fastener until an inner shoulder of the collar step causes an outer section of the ring to shear from the anchor section. A lock ring groove is formed in the stem midsection of smaller diameter at the intersections of the stem neck and midsection. The shear ring may be formed of shaped wire which is wrapped around the fastener stem, while the expander collar is an annular element next to the shear ring. The shear ring dimensions and material properties can be modified to alter the fastener characteristics.