Patent GB-1465640-A (GB)
Title: Wire bender
IPC: B21F35/02
Filed: 1974-07-02
Abstract: 1465640 Bending wire; shearing A W E GUENTHER 2 July 1974 [3 July 1973] 29330/74 Headings B3E and B3W A hook is formed on a straight wire by positioning the wire, moving an arbor in the direction of the longitudinal axis of the wire so that the wire becomes tangential to the arbor and moving a bending head to bend the wire around the arbor. In the apparatus described, the wire is a spring end, bent as a preliminary step to extend parallel to the spring axis, the wire is bent round the arbor in consecutive steps by two heads, and the arbor is then withdrawn from the hook in a driection along the longitudinal axis of the arbor. Fig. 1 shows a holder for a spring 500 with a leg 502 to be sheared and shaped, comprising a peg 61 over which the spring is fitted to abut a base 58, and a plate 62 offering an edge to the spring such that when the plate is advanced against the spring by pneumatic cylinder 76, the edge is wedged between turns of the spring and holds it against the peg with the leg lying against a mandrel 92. The position of the spring when so held is adjustable in directions X, Y by set screws 52, 65. In the first step. the leg is cut to length by a pivot of shear jaws 132, 134, Fig. 4. Jaw 132 is mounted on a shank 142 pivoted at 138 to a fixed bracket 136, and during shearing is supported by engagement of stop 158 on the shank with notch 153 on lever 152 pivoted on a fixed pin 156 and urged towards the position of engagement by spring 160. Jaw 134 is mounted on a shank 140 pivoted to shank 142 at 144 and ending in a pin 148 engaged in slot 130 of a cam block 126 reciprocable by pneumatic cylinder 122. Starting from the position shown, outward movement of block pivots shank 140 to shear leg 502, and subsequently an adjustable pin 170 contacts lever 150 to pivot it and disengage notch 153. Further movement of block 140 then retracts shank 140 bodily to move both jaws away from the leg. On return movement of the block (after shaping of the leg) springs 166, 160 restore the position shown. The apparatus of Fig. 4 is bodily adjustable in three directions at right angles. The sheared leg is next bent parallel to the spring axis by rotation of arm 46, Figs. 1 and 4, on shaft 20 by pneumatic cylinder 28 and rack and pinion 25, 26. Arm 46 is vertically adjustable by set screw 44, and the datum position of jack 28 is adjustable by set screw 25. The hook is then formed on the leg end by the apparatus of Figs. 6, 7 and 11. This consists of a guide 408, mandrel 304, and bending heads 288, 334. These are all mounted on respective pivots on a slider 254 in the exploded view of Fig. 7. In particular, the bending elements are in levers 270, 330 on vertical pivots and mandrel 304 is on a block 294 on a horizontal pivot pin 298. The slider is reciprocable by pneumatic cylinder 236, Fig. 6, in ways 253 in a collar 252 rotatable within clamp 230 so that the plane of formation of the hook can be adjusted. The mounting levers, slider 254, and collar 252, are provided with various stops, slots, cams, springs, and latches, so that as slider 254 performs its out and return strokes, the various bending actions and retractions take place in sequence. These actions are that first the apparatus is advanced bodily so that guide 408 passes to one side of leg 502 and positions the leg against mandrel 304. Then head 288 swings across to wrap the leg 90 degrees round mandrel 304, as shown in the plan of Fig. 11. Next head 334 moves parallel to the leg to wrap the leg further round the mandrel, and then swings behind the mandrel a little to complete a bend of rather more than 180 degrees to allow for spring back. Head 334 clears the hook before being retracted in the return stroke, and mandrel 304 is lowered to clear the hook similarly. Provision is made for positioning the apparatus as a whole in three directions at right angles, and for changing the bending elements and adjusting their position. The bending sequence may be performed manually by operating bar 248, Fig. 6, to facilitate making such adjustments.