GB863480A - Improvements in or relating to metal working machines - Google Patents

Abstract

863,480. Bending. WILMOT-BREEDEN Ltd. Dec. 24, 1957 [Sept. 25, 1956; Sept. 20, 1957], Nos. 29304/56 and 29677/57. Class 83 (4). A machine for bending or shaping metal workpieces comprises a former having a working profile corresponding to the full length of the shaped workpiece, means for clamping the workpiece to the former, comprising two clamping units positioned respectively on opposite sides of the middle of the former profile, a forming or press member for engaging the workpiece over a small area thereof, means for urging the forming member into engagement with the workpiece and means for relatively moving the forming member along the length of the workpiece, one clamping unit being operative to clamp the former to the workpiece whilst the other clamping unit is inoperative, whereby the workpiece is bent or shaped in two successive halves. Two formers 16 spaced one above the other are mounted on a table 15 rotated by hydraulic means 21 comprising one, two or three piston and cylinder units. A cross-head 28, on which is pivoted a head 31 carrying two profiled rollers 33 for pressing the workpiece against the former 16, is urged towards the former by an hydraulic piston and cylinder unit 26 and the orientation of the head 31 is altered by an hydraulic piston-and-cylinder unit 36, pivoted on an extension 42 of the head 28, rocking the head 31 about its pivot. In operation, two partially-formed car bumper blanks 10 of U cross-section are presented to the formers 16, positioned as in Fig. 5, by a head 64 pivoted on a reciprocated block 56, as described in Specification 863,482, to which reference is made. A T-headed clamp 44 nearest the roller head 31 is then actuated by hydraulic means 43 to hold the two blanks to the formers. The formers 16 then rotate first quickly then slowly and the roller head 31 moves towards the formers, first quickly then slowly, to engage the blanks slightly to one side of their centres. The angular control unit 36 is then unlocked and the formers rotated quickly until the first halves of the blanks are bent, Fig. 10. The speed of rotation of the formers 16 is controlled, through a valve arrangement, by the pressure exerted by the roller head. The formers 16 are then stopped, the head 31 withdrawn, the other clamp 44 actuated to hold the blanks and the first clamp 44 released. The head 31 is returned and the formers 16 rotated in the opposite direction to bend the other halves of the blanks. After corner blocks 18 in the formers 16 have been retracted, the finished blanks are removed by jaws on another head pivoted on the block 56. The bending pressure is reduced for the ends of the blanks. Specification 665,560 is referred to in the first Provisional Specification. According to the second Provisional Specification, workpieces may be bent to circular form on circular formers having only one clamp, the roller head being replaced by a shoe. Specification 863,481 also is referred to.