Patent ID: 6233988
Filing Date: 2001-05-22
Classification: B21D

Abstract:
A bending method for use in a bending machine, having a table and a support frame rigidly joined by a pair of side frames, which bends a sheet-like workpiece by a cooperative movement toward each other of a movable die and a fixed die, the movable die being supported by a ram which in turn is supported from said support frame at three or more shaft-load imposed points by respective drive shafts, the fixed die being supported, in an opposing relationship with the movable die, by a top surface of the table,said sheet-like workpiece being interposed between the fixed and the movable dies and having two end positions and a center position along its interposition with said dies,the bending method comprising the steps of:obtaining the difference between a bend angle of the workpiece after the bending operation and a target bend angle, at at least three positions, that are, the ends and center of the workpiece; andobtaining, according to the differences between said angles at each position, a correction value for the amount of cooperative movement, by movement of the ram, at each of the shaft-load imposed points which correspond to the respective positions of said drive shafts.