GB613882A - Improvements in or relating to hollow rivets and the setting thereof - Google Patents

Abstract

613,882. Blind riveting. BRITISH UNITED SHOE MACHINERY CO., Ltd. (United Shoe Machinery Corporation). June 15, 1946, No. 18064. [Class 43] A headless rivet, for use in blind riveting, has a thin-walled portion part of which projects from the work at each side thereof, and a thick-walled portion which preferably has an internal screw thread in which setting means engage. A method of blind riveting wherein the rivet is initially headless comprises forming a head by curling over one end in an annular recess in a riveting device, and then deforming another part into a retaining flange at the other side of the work. The riveting device also comprises means for pulling on setting means, and spring-controlled gauging means which move relative to a work-engaging abutment to facilitate positioning of the rivet. The said abutment may have an annular tapered pilot portion which enters the rivet to minimize its tightening on to the setting means., In one form a hollow, headless rivet is externally cylindrical, but half of it has an internal screw thread and is thicker than the other half which is internally smooth, the thickness at the base of the threads being equal to that of the thin half. The riveting device resembles that described in Specification 567,075, but the abutment 4 has an annular work-engaging part 50 having a recess 52, which surrounds the rod 10 and provides adjacent thereto an annular pilot portion 54, which tapers to a sharp ridge and projects beyond the rest of the part 50. The outer edge of the recess 52 is bounded by a flat, annular surface 56. Adjacent the part 50 the abutment 4 is reduced to form a cylindrical bearing surface 58 on which is slidably mounted a two-part collar 60 embraced bv a spring-urged ring 66. A stop surface 62 on the collar 60 is normally held in engagement with a shoulder 64 of the abutment 4 by the spring 68, so that said collar extends beyond the ridge of the pilot 54. In use the thin-walled part of the rivet is pushed on to the rod 10, the projecting part of which is of such a length that the end of the rivet engages the ridge of the pilot 54, and the rod.10 is screwed into the rivet as in Specification 567,075.- Next the rivet is thrust through a hole in a workpiece, until the latter is engaged by the collar 60 which acts as gauging means, positioning the rivet so that a desired amount of the thin-walled part projects on either side of the workpiece. On pressing down the lever 30 to retract the rod 10 the ridge of the pilot 54 minimizes tightening of the rivet on to the rod 10 during setting by entering and expanding the rivet at its thin-walled end which is then curled over in the recess 52 to form a head ; the head-forming operation, during which the abutment 4 is thrust against the workpiece, is limited by the engagement of the surface 56 with the workpiece, the collar 60 having yielded against the spring 68. The formation of a retaining flange in the rivet on the other side of the workpiece, and the removal of the rod 10 from the set rivet is accomplished as discribed in Specification 567,075. For setting a smooth-bored headless rivet having a thin-walled and a thick-walled portion by means of a headed mandrel, the stem of which is a snug fit in the bore of the thick-walled part use is made of a tool similar to that described in Specification 348,818, but having the same abutment 4, collar 60, ring 66 and spring 68 as described above. Preferably the collar 60 is shorter than before since part of the pilot 54 enters the thin-walled part of the rivet before any pull is exerted on the mandrel. Specification 459,973 is referred to and Specification 106,169, [Class 89 (i)], also is referred to in the Provisional Specification.