Patent GB-1227614-A (GB)
IPC: B21F35/00
Filed: 1968-06-11
Abstract: 1,227,614. Making springs; angular bending. LEAR SIEGLER Inc. 11 June, 1968 [16 June, 1967], No. 27639/68. Headings B3A and B3E.  Apparatus for bending linear metal material comprises bending means for displacing a product portion of the material in a radial plane relative to a stock portion to form a bend; means for supporting the bending means for rotation about the longitudinal axis of the material, means for advancing the material longitudinally towards the bending means to establish axial positions; means for rotating the bending means to establish the radial direction of the bend at the axial positions and cutoff means for severing the material after a predetermined number of bends. The apparatus comprises a bending and cut-off head 14, a head driving and support housing 16, a feed mechanism 18 and a wire straightening device 20. A rotatable programming control cam 22 is housed in a supporting frame 10 (Fig. 1). Bending and cut-off head.-This includes a wire guide member 24 having a bending anvil 32 (Fig. 5). The diameter of the guide member bore is adjusted by a set screw 36. A grooved bending roller 40 is journalled in plates 42 and actuated by a reciprocating member 50 slidable on a spindle 30. A spring-loaded wire cut-off pin 52 is actuated by a lever 58 pivoted on the spindle 30 and operated by an hydraulic motor 76 via a rod 74 provided with rollers 72 which engage a disc 70 on a cut-off slide 68 (Fig. 2). The bending die slide member 50 is attached to a slide 80 attached to an hydraulic motor 88. To change the plane of the bend the bending roller is rotated angularly about the axis of the wire W by rotating the spindle 30 by rack and pinion gearing controlled by the cam 22. The angle is determined by a multi-position stop assembly engageable by a flange 82 on the slide 80 (Fig. 3a). The assembly comprises a disc 126 on a shaft 128 rotated by an hydraulically operated rack and pinion gearing (Fig. 12, not shown). The disc is provided with three stops 150, 152 and 154 (Fig. 8) the central stop constituting a 90 degree bend. The arc through which the bending roller 40 is moved is determined by the maximum position of slots 48 in the reciprocating member 50.  Feed mechanism.-This comprises a pressure roll 178 carried on a pivotal arm 180 connected to an hydraulic motor 182. The roll is driven in synchronism with the control cam 22 by chain and sprocket gearing so long as the pressure roll is urged against a drive roll 174 by the motor 182. Programme control.-The cam template 22 carries a plurality of timing pins projecting from the rear face and arranged in circles of varying radii. Limit switches LS1-LS5 are supported on a radial bracket attached to the apparatus frame 10 and these effect the initial control functions by which the various hydraulic motors are actuated each pin position on the template determining the point in a bending cycle at which the various functions are performed. Other switches (not shown) are actuated to indicate the retracted position of the bending head and the retracted and extended position of the cut-off pin. In a modification a programming template 22<SP>1</SP> (Fig. 24) having a pair of axially offset peripheral cam surfaces 252 and 254 is substituted for the cam 22. The cam surface 252 operates to programme the angular position of the bending head 14 by means of a follower 256 on a spring-loaded bell crank 258 connected to a linear variable differential transformer 266. The cam 254 and its follower 282 actuates a linear variable differential transformer 296 for controlling the arc through which the bending die moves. This modification gives an infinite variation in bending head stroke. Operation.-The angular position of the bending head is determined by the cam pattern on the template 22. During the formation of bends a-f of a seat cushion spring shown in Fig. 17 the bending head is positioned so that the roller 40 moves in a vertical plane, oscillating 180 degrees between successive bends to form the spring section 248. To form the bends g-j the cam template moves the bending head to form section 250 in a plane at right angles to that of section 248 and section 246 is formed by movement of the bending head through 45 degrees.