GB1233135A - - Google Patents

Abstract

1,233,135. Programmed control of machine tools. SIEMENS A. G. March 14, 1969, [March 15, 1968], No.13642/69. Heading G3N. A storage medium storing data for the numerical control of a machine is prepared by determining and storing selected co-ordinates of prints in a model for which the shortest line between points is within a predetermined distance of the actual contour between the points. As shown, a tracer T is mounted on a slide system, (not shown), carrying co-ordinate digital position transmitters G, defining the position of the tracer, the outputs of which are fed to a differential gate DG through an evaluator JA. The tracer moves relative to its suspension and analogue displacement signals are fed through an analogue-to-digital converter ADW to the gate DG. The inputs to the gate DG are summated, with the correct sign, in the gate. The outputs of the gate are used (1) in a circuit PS to derive the square of a pseudo-chord, defined as the sum of the squares of the distance between the last stored point on the curve and the present position of the tracer and (2) in a circuit Kto derive the square of length of the corresponding arc of the curve. The derived squared values are compared in a comparator V and at equality the comparator issues a storage command to stores Sp1 to Sp n for position values from the gate DG. When the stores are full, tracing is interrupted and the contents of the stores are fed to a punched tape machine L. The resulting punched tape is used in a numerically controlled machine tool to reproduce a model being scanned by the tracer.