ES353367A1 - Apparatus for bending - Google Patents

Abstract

Bending apparatus for bending a workpiece comprises a die assembly separable into a head die block and base die block and including a bending hub: means for separating the head die block and the base die block from one another to receive a workpiece and for forcing together both said blocks to clamp the workpiece therebetween means for rotating the die assembly with the workpiece clamped therein to bend the workpiece about the bending hub, and a fixed pressure die adjacent the hub for forcing the workpieee against the bending hub during bending of the workpieee. The left and right die assemblies 37, 39 are driven by chain drives 41, 43 actuated by power cylinders 45. A push-up assembly 53 is used to force the tubular workpiece W forward during the bending operation to assure proper wall thickness after bending and to avoid collapse of the workpieee. The push-up assembly is reciprocated by a pressure cylinder 221 and jaws 225 and 227 are operated by toggle mechanism 255, 253, 249 and a pressure cylinder 223 to clamp the workpieee (Fig. 4). At the rear end 33 of the machine an optional automatic feed assembly 55 is provided. The die assemblies 37, 39 are connected so that the head die blocks 59, 61 can be raised or lowered together by hydraulic cylinders 49, 51 (Fig. 2) in order to clamp the workpiece against their respective base die blocks 63, 65. A wiper and pressure die assembly 133 is located adjacent the entrance to the die blocks (Fig. 10). A slot 134 in the assembly 133 provides sufficient resilience to permit easy sliding of the workpiece. The left and right die assemblies 37, 38 are mounted on shafts 87, 89 having splined portions for mounting drive gears 151, 153 which engage the chain drives 41, 43 respectively. A spring-loaded floating member 211 assists in returning the shafts 87, 89 downwardly to lower the die blocks 63, 65 to an open position. In operation the workpiece to be bent to serpentine form is fed into the machine by the feeder assembly 55 and after feeding predetermined amount into the die assembly, the push-up assembly clamps the tube. For making a clockwise bend (Fig. 10) the right die assembly 39 is completely rotated to press against the wiper and pressure die assembly 133 and the channel 119 of the left die assembly is aligned with the workpiece and by rotating the left die assembly while retaining the right die assembly in its clamped position the bend is achieved. By reversing the procedure left and right U-bends are produced in a tube for use in a heat exchanger. In a single die assembly 300 embodiment an upper die block 301 and a lower die block 303 are utilized. The assembly in eludes a hub 311 with an extending arm 313 (Fig. 16). The apparatus is supported in a frame 317 housing a vertical drive assembly 323 comprising a power shaft 327 keyed to a drive gear 325. The upper die block is actuated by an hydraulic cylinder 343 assisted by a coil spring 356. A wiper and pressure die assembly 373 is located along the line of feed of the workpiece W directly adjacent the die assembly to assure rigidity where buckling normally would occur as a result of the bending.