| 摘要 |
<p>Controlled or automatic unrestrained bending of sheet metal between a punch and an open V-block type tool is carried out in power presses in which the path of the punch is not limited and which may be stopped at any point of its stroke. The workpiece is deformed from a definite starting shape to a definite end shape. This is achieved with the help of measuring probe which monitors either half or the whole included angle of deformation of the workpiece and thus the angle by which it has been deformed as a control value x, which is compared with a programmed value xk, which is determined by the stroke of the press stand. It thus permits at any time the calculation of the deviation xw = x - xk, which after a preset interval is transformed into an adjustment working stroke.</p> |
