Patent GB-1363274-A (GB)
Title: Apparatus for setting fasteners
IPC: B21J15/34
Filed: 1971-07-22
Abstract: 1363274 Riveting D M JAFFE 22 July 1971 [11 Aug 1970 11 May 1971] 34381/71 Heading B3U Apparatus for setting rivets having apertures therein comprises a mandrel 36 expandable from an unexpanded state to an expanded state mounted on a shaft 24 for movement relative to an anvil surface 26, the mandrel being adapted to receive a rivet thereon in its unexpanded state by effecting relative axial movement between the mandrel and the aperture in the rivet, the mandrel 36, in its unexpanded state, entirely surrounding the shaft 24, means for expanding the mandrel to its expanded state wherein a portion thereof has a cross-section greater than the aperture in the rivet, and means for driving the expanded mandrel towards the anvil surface to set the rivet. The expansion of the segmented end of the mandrel 36 is effected by moving an enlarged head 30 of the shaft 24 rearwardly while biasing a cylinder part 40 of the mandrel forwardly with a spring 41. Continuation of the rearward movement of the shaft allows a collar 34 on the shaft to engage the rear wall of the cylinder and thus move the expanded mandrel rearwardly to set the rivet. An escapement mechanism 84 for a semi-automatic blind riveting machine, Fig. 3, is described in which rivets held in a shoot 100 are fed one at a time to a pivoted support 86. In operation the mandrel and shaft are driven forward by a spring 150 and picks up a rivet on the support 86. On continuing the forward movement the leading edge of the cylinder 40 engages angled part 120 of slot 114 and carries the slot forward against the bias of spring 122 to allow the stack of rivets to drop on to a slot 108. The leading part of the mandrel pivots open a nose 92 and places the rivet in a workpiece. The sleeve is then expanded and pulled rearwardly as described above. As the mandrel approaches the position shown in Fig. 3, the spring 122 forces slot 114 back into the shoot to support all the rivets except the lowermost one. The back of cylinder 40 then engages angled part 112 of slot 108 and drives it back against the bias of spring 110 thus allowing the bottom rivet to fall on to the support 86. A modified operation of the machine of Fig. 3 is described in which eyelets are set in a four stroke cycle. After placing an eyelet, mounted on the sleeve, in the workpiece, a modified collar 34<SP>1</SP>, Fig. 7, having key 166 adapted to move in a keyway 168 in cylinder 40<SP>1</SP>, is driven back in the cylinder with the keys moving from parts A to B. This causes expansion of the mandrel and, on further rearward movement of collar 34<SP>1</SP>, setting of the eyelet. After the setting of the eyelet further movement of collar 34<SP>1</SP> rearwardly is precluded by the set eyelet acting against the expanded collar. The collar 34<SP>1</SP> is then moved forward with keys 166 moving from parts B to C so as to contract the expanded mandrel. Finally the collar 34<SP>1</SP> is moved rearwardly to point D so that the contracted mandrel can be removed from the eyelet. The shapes of the shaft and segments 42 of the mandrel 36 are described, Figs. 2A-2C not shown. The mandrel can be constructed to punch its own hole in a workpiece.