METHOD AND DEVICE FOR DISTANCE DETERMINATION

摘要

The invention relates to a method and an apparatus for setting a defined distance between a workpiece surface with a modifiable height and the vertically movable engineering tool. Aim: universal applicability without additional use of cardboard. Object: to adjust the defined distance of the guard from the stack surface by scanning the guard in a contact-free manner. The object is achieved according to the invention in that a guide rod 81 adjoins a piston rod 3, the two components being connected by a horizontally and non-positively guided guideplate 84. Transparent finger guard panels are mounted in the lower region, on the guide rod 81, one or more interchangeable reflex light barriers 7 being embedded in the lower edges of the said finger guard panels. One or more interchangeable reflex light barriers 5, above which the interchangeable reflex light barriers 7 are situated, are arranged in the rear part of the working surface, and one or more photodiodes 6 are situated in the front region of the working surface. The output signals of both interchangeable reflex light barriers are compared by means of a differential amplifier and an upper switching threshold S1 of low potential and a lower switching threshold S2 of higher potential are derived from the differential signal.