Patent GB-907586-A (GB)
Title: Improvements in machines for shaping sinuous spring strips
Inventor: CORP PAUL METZGER
IPC: B21F35/00
Filed: 1961-05-05
Abstract: 907,586. Bending; twisting. AMERICAN METAL PRODUCTS CO. May 5, 1961, No. 16347/61. Class 83 (4). A spring strip 15, Fig. 1, having loops formed by transverse torsion bars 16 joined by longitudinal bendable bars 17, is held in a slot 22 in the base 150 of a machine, Fig. 6, by clamping blades 44, 46 movable in and out of the slot and is shaped in a predetermined manner by rotatable heads 23 to 34 associated with the clamping blocks and also movable in and out of the slot, the clamping blocks being arranged to release the shaped strip after the heads 23-34 have retracted out of the slot. The blocks 44, 46 are respectively formed with . aligned angular-shaped anvils and recesses and are provided on each side of the slot 22. The blocks 44 are first advanced into the slot to support the strip 15 when the latter is introduced therein. The blocks 46 are then advanced and moved downwardly to clamp the central portion of the strip which is located with the torsion bars 16 of its end portions aligned with the shafts 35 of the heads 23-34. The latter are then advanced to engage the spring strip and are sequentially rotated in the required direction and immediately after retracted out of the slot so as to twist the torsion bars 16 in sequence starting simultaneously from the extremities of the strip inwards in order to form apices 37, 38, 41 to 43 in the end portions of the strip as shown in Fig. 14. When twisting is completed and all the heads retracted, the upper blocks 46 are moved further downwardly to bend the bendable bars 17 of the strip so as to change its flat central portion into an arched shape as shown in Fig. 14. The blocks 46 are then raised and, together with the blocks 44, are retracted in order to allow the shaped spring strip to fall through the slot out of the machine. The heads 23-34 are respectively rotated and advanced by pairs of levers 81, 98, Fig. 8, which are each pivoted by cam surfaces on either side of cam discs 68 mounted on shafts which are provided parallel with, and on either side of, the slot 22 and which are connected through bevel gearing by a transverse shaft so as to be operated in unison by a motor which drives one of the shafts through sprocket wheels and chain. Each lever 81 operates, through a pivot 86 adjustable in an arcuate slot 85, an adjustable link 88 universally connected to a vertically movable bar 91 having teeth 92, Fig. 1, which mesh with teeth 93 on one of the head shafts 35. The shaft 35 is connected through a block 95 to the bellcrank lever 98. The cam surfaces are so formed and related to each other that the lever 98 is first rocked to advance the shaft 35 after which the lever 81 is rocked to rotate it. The blocks 44 are moved towards and away from the slot 22 by levers 108 operated by cam discs 55, 65, Figs. 1, 6 and 7, mounted on the parallel shafts. The levers 108 are joined to the blocks 44 by pairs of bars 113. The blocks 46 are pivotably secured to the blocks 44 at 114 and are swung relative to the blocks 44 by pairs of toggle linkages 116, 117, 122 operated through pairs of bell crank levers 123 which are actuated by cam discs 55, 56 and 64, 65. The spring strips 15 are fed from a forming machine on an arm 130, Fig. 6, from which they are conveyed by spaced conveyer chains 131 on to spaced bars 135. The strips slide down the bars against fingers 136 from which the endmost one is delivered flat on to a reciprocable plate 154 by spaced arms 137 operated by a lever 142 when the latter is actuated by the cam plate 145 upon a reciprocable plate 156 in its retracted position. The plate 156, which is secured to the plate 154, is guided in a pair of ways 155 in the base 150 of the machine and is reciprocated by links 164 and arms 163 secured to a shaft 158 which is rotated in bearings on the base 150 by a cam-operated lever 162. The plate 154 is then advanced by the lever 162 to deliver the strip 15 to fingers 168 and to clamping elements 184 provided on a bar 173 secured to rods 174, Fig. 5. Upon retraction of the plate 154 the strip is suspended by the fingers 168 and its ends are engaged by the clamping elements 184. The rods 174 are then moved vertically through ratchet means by a lever actuated by the cam disc 64 to lower the bar 173 to deliver the strip 15 on to the blocks 44. When the strip is clamped by the blocks 46 the lever is rocked back raising the rods 174 and moving the fingers 168 and the clamping elements 184 out of engagement with the strip.