| 摘要 |
<p>A workpiece such as a steel profile to be perforated at predetermined distances from a longitudinal reference surface thereof is moved past a plurality of perforating tools, such as punching or drill presses, mounted on a main slide and associated with respective sensors carried on an ancillary slide, the two slides being provided with a rack-and-pinion coupling working into a position detector. Each sensor comprises two sensing heads movable, upon selective activation prior to operation of the corresponding tool, transversely to the workpiece path with a slight relative offset; the ancillary slide is displaced until the reference surface is detected by one-but not both-sensing heads whereupon a corrective motion is imparted to the main slide under the control of the position detector.</p> |
