GB1200178A - Improvements relating to bending machines for bending metal bars - Google Patents

Abstract

1,200,178. Angular bending; straightening; making bumpers. H. GOBLE. 23 Nov., 1967 [29 Nov., 1966], No. 53358/66. Headings B3A and B3E. A metal bar bending machine, particularly to shape car bumpers with a straight portion 24 and curved ends 26, comprises a clamp 32 and a pair of curving dies 50, 52 mounted on a saddle 40 slidable in a slot 30 at each side of the clamp. The dies each have hardened metal inserts 54 which extend over the initial part of the curved opening. The inner die 50 is pivoted to the saddle about a pin 68 and is movable by a piston cylinder assembly 84 to separate the dies. The pin 68 is mounted on a slide (70), Fig. 5 (not shown), which is spring-biased away from the outer die 52 between guides 72. A cam follower 74 prevents the slide moving the inner die away from the outer die until it has been pivoted by a small amount about the pin 68 in a direction opposite to the direction of entry of the bar. An internal die 66 for the hollow bar is mounted on a shank 94 which extends through the longitudinal slot in the bar. The thickness of the die 66 is such that it can be removed through the slot after it has been rotated through 90 degrees. A back-up member 101 prevents distortion of the die and the member is removed from behind the die before the rotation. The curved ends of the bar which extend beyond the dies 50, 52 when the saddles are in their innermost positions are each straightened between an anvil die 130 and a wiper die 132. The die 130 is mounted on an arm 134 adjustably positioned about an axis 136 on the saddle 40. The wiper die 132 is mounted on a slide 142 movable between guides 144 adjustably positioned on a slotted table 120. The end of the slide has rollers which engage an adjustable surface 152 so that when the motor 128 rotates the nut 126 the table is moved to cause the die 132 to co-operate with the die 130 to straighten the curve. The die 130 and the surface 152 are mounted parallel to form a straight portion at each end of the bar although they may both have any similar curvature. The central part of the bar is prevented from buckling by clamps 36 which are slidable along the bar and urged apart by springs 38. When the saddles 40 are moved together by the piston cylinder assemblies 44 the clamps 36 are brought closer together. The actuation of the power cylinders and the electric motors 128 are preferably arranged to operate automatically in a preset sequence.