Patent GB-793365-A (GB)
Title: Improvements in or relating to tools adapted for use in blind riveting
IPC: B21J15/06
Filed: 1954-12-03
Abstract: 793,365. Blind-riveting. TUCKER EYELET CO., Ltd., G., and NEWSTEAD, C. Dec. 2, 1955 [Dec. 3, 1954], No. 34994/54. Class 83 (4). A power-operated tool for blind-riveting comprises a fluid pressure chamber, a piston reciprocable in the chamber, and lazy-tongs mechanism associated with the piston, abutment means and pulling means of the tool such that in blind riveting the abutment means remains stationary in engagement with the rivet and fluid pressure admitted to the chamber imparts a comparatively long stroke to the piston and a comparatively short stroke to the pulling means to set the rivet. Closure members 12 and 14 are secured to the chamber 10 by tie rods 16. The front closure member 12 carries a hollow sleeve 20 and nose piece 22 into which the projecting part of the mandrel stem is inserted. A cylindrical collet C attached to a draw-bar 28 slides within the sleeve 20 and a spring-loaded plunger 34 is accommodated within the collet C. In front of the plunger the jaws 40 of the collet are retained by a screw cap 42. Rearward movement of the jaws against the plunger spring 38 allows the jaws to open by sliding along the part-conical internal surface of the cap 42. Thus with the draw-bar in its foremost position in the sleeve 20 the jaws are open. Within the chamber 10 the draw-bar is attached to a collar 58 which is itself attached to the piston 60 by a lazy-tongs mechanism. Compressed-air is supplied to the tool handle 100 which accommodates a piston valve 112 operated by a trigger 122. Four passageways p, q, rand s lead from the valve chamber; p to atmosphere, q to front of chamber 10, r to rear of chamber 10, and s to the interior of the sleeve 20. In operation, the nose-piece of the tool is placed against the rivet head and the trigger is pulled to move the piston valve forwardly and supply compressed air to the rear of piston 60 to set the rivet and break the mandrel. The piston 60 is returned on release of the trigger and air at the rear of the piston is expelled into the sleeve 20, where it passes through the interior of the collet, through holes 152 into the hollow plunger 34 and thence between the jaws 40 to forcefully eject the broken-off part of the mandrel. In a modification the handle 100 may be disposed at the rear of the tool or arranged normal to the chamber 10 (Fig. 6) and the draw-bar terminates in a rack 166 which meshes with a pinion 168. A second draw-bar 170 attached to the lazytongs mechanism also engages the pinion 168 such that an upward stroke of the piston pulls down the rack 172 which turns the pinion and pulls the collet. In a further embodiment, the sleeve 20 and chamber 10 are disposed at an angle of 30 degrees to one another (Fig. 7) and in a still further embodiment the sleeve is offset but parallel to the cylinder (Fig. 8). In the latter embodiment the piston 60 moves rearwardly to set the rivet the lazy - tongs mechanism pushing forwardly a toothed drawbar 182 meshing with a toothed double segment gear 184 which also meshes with teeth on the draw-bar 28. Specifications 348,818, 405,993, [both in Group VII], 567,586, 578,104 and 587,938, [both in Group VII], are referred to.