Patent GB-1463522-A (GB)
Title: Bending machines
IPC: B21D7/024
Filed: 1974-09-11
Abstract: 1463522 Bending RUSSEL BOWEN SYSTEMS Ltd 26 Aug 1975 [11 Sept 1974] 39612/74 Heading B3E A bending machine comprises a former 10, a bending arm 13 provided with a bending tool, a clamp 14, and actuating mechanism for moving the former between an open position spaced from the tool and clamp, and an operative position in which the former thrusts the work against the tool and clamp, and for driving the arm about a fixed axis to bend the workpiece about the former. In Figs. 4 and 5, the bending arm 13 is mounted on a hollow shaft 27 journalled in a casing of the machine, and the former 10 is mounted by eccentric 11 on a head 28a of concentric shaft 28. Arm 30 is pivoted at one end to peg 31 in a fixed bracket 32 and at its other end to peg 29 in the former, whereby as shaft 28 is rotated, the former moves parallel to itself between the two positions shown in Fig. 4. The bending tools are rollers 25 on bolts 46 adjustable in slots 46, and clamp 14 is adjustable by mounting 21. In use, the former is raised by rotation of shaft 28, a tubular workpiece is advanced over the clamp and rollers to abut a stop (not shown), the former is lowered, the bending arm rotated to bend the workpiece, and the former raised to release it. The shaft drives each comprise advance and return hydraulic pistons 33, 59, and 36, 62, see Figs. 5 and 7, driving racks meshing with pinions on the shafts. In Fig. 7, manual operation of switch 55 operates solenoid 58 which sets valve 57 such that pressure fluid is admitted to line 43. This operates piston 36 to lower the former, and when its stroke is completed, pressure builds up in the line sufficiently to open valve 63 and actuate piston 59 to bend the workpiece to the extent set by adjustable stop 35a. On completion of this stroke, pressure in line 52 builds up further to open valve 64, damping fluid through restriction 64a and operating contact 66 which through controller 67 and solenoids 58 and 68 changes over valve 57, so that both return pistons 33, 62 are operated. At the completion of their strokes, operation of contact 66 a second time resets the apparatus. A manual switch 55a resets the apparatus at any time. The machine may be converted for bending in the opposite sense by using a reversible arm 13, repositioning the eccentric in bore 70 of head 28a (Figs. 4 and 5), repositioning clamp 14 and bracket 31, and using stop 35 and changing over valves 71 and 73 (Fig. 7). Fig. 9 shows an installation where four such machines are mounted to effect two bends sequentially or simultaneously by outer machines 90, 91, which are then retractable perpendicular to the plane of bending along rails 92 by rams 93, so that two more bends may be made by inner machines 80, 81 to form the workpiece into rectangular shape. The inner machines may be adjustable in separation along a rail. The hydraulic apparatus of Fig. 7 in such an installation operates the outer pair of machines, and is duplicated for the inner pair, an interlock and timing device 96 preventing the "return" of the outer part, which releases the workpiece, until the workpiece is gripped (but not bent) by the inner pair, whereupon the cycle of the outer pair continues, and upon completion causes actuation of the rams 93 to retract the outer pair, and after a time delay causes operation of the inner pair to be completed. In Fig. 12, the units 80, 81 are mounted on rail 83 by turn table devices 82, enabling two bends to be made in a workpiece 87 in parallel planes at right angles to the plane of the first two bends, e.g. for a perambulator handle or seat frame.