Abstract: A self-plugging blind fastener of the break-stem type, is suitable for fastening apertured sheets together, and comprises a headed tubular body and an elongate stem disposed in the bore of the body. The stem comprises a plug, and a stem-tail connected to the plug by a breakneck which is concealed by overlapping lips. The plug has a stop face, and an annular locking groove between the breakneck and the stop face. The body has a deformable locking collar upstanding above an adjacent region of the upper surface of the head. The diameter of the bore reduces, to provide a stop face and a locking region of smaller diameter, within the head. The fastener is set by pulling the plug into the bore until the stop faces meet, to form a blind head, and then deforming the collar to force the body to bulge into the locking groove of the plug.

Abstract: A threaded fastener for installation in threaded engagement with an initially unthreaded apertured workpiece and which after installation can be removed in the manner of a screw or bolt, has a shank and an enlarged head. At least part of the shank intermediate between its ends has an external screw thread having a sharp crest, and can be radially expanded to cause the thread to embed in the workpiece. A bore extends through the head and the entire shank or at least the threaded port of the shank for receiving means for expanding the shank. An end portion of the shank remote from the head may be unthreaded to avoid splitting of the shank during expansion.The method of installing the fastener involves pulling a tapered mandrel along the bore to expand the shank. The mandrel may have a key-forming head of non-circular cross-section whereby the bore of the fastener can be adopted to receive a key of non-circular cross-section for turning the fastener in the workpiece.

Abstract: A three piece blind fastener of the kind comprising a tubular nut having a head at one end and a tapered nose at the other end, an expansible sleeve, and a headed bolt threadedly engaged with the nut for forcing the sleeve on to the nose of the nut to form a blind head, has the thread of the nut provided with a locking zone in which the bore of the nut is constricted and, in cross sectional shape, a closed non-reentrant non-circular curve so that the nut resiliently interferes with the bolt.A die, and a method of providing the nut with the locking zone by means of the die are disclosed. The die has a tapered aperture having a cross sectional shape corresponding to the desired shape of the locking zone, and the method involves forcing the tapered nose of the nut into the aperture so as to constrict the bore, in a zone spaced from its ends, to the desired extent and impose the non-circular cross sectional shape on the constricted zone.

Abstract: A blind, self-plugging rivet assembly for securing together two members (42, 43) is of the type comprising a tubular shell (13) with an enlarged head (14) at one end, and a stem (12) which extends through the bore (15) of the shell, the stem having an enlarged head (38) beyond the tail end (18) of the shell.The shell has a weakened zone (19) formed by three slits (22) extending along part of the shell shank and spaced apart equiangularly around it. The stem head (38) lies beyond the shell tail end, and has an underhead surface (39) which is slightly convex and is bounded by a sharp edge (40).The stem has a pulling portion (32) connected by a breakneck to a plugging portion (31) which is an interference fit in the shell bore. Adjacent the breakneck the plugging portion has a cylindrical skirt which, when the rivet has been installed, can be deformed outwardly to lock the plugging portion to the shell. A bead on the stem guides the tool for deforming the skirt.