GB1427244A - Electrical control system for a machine tool - Google Patents

Abstract

1427244 Cutting by fusion MESSER GRIESHEIM GmbH 23 July 1973 [22 July 1972] 34965/73 Heading B3V [Also in Division G3] For a machine 10 {flame, laser, or plasma cutting} with at least two tools 21, 22 and arranged to be controlled either by a photoelectric line follower 11 or numerical continuous path controller 12, for partly cutting, partly centre-punching a workpiece, there is provided in the signal line between units 11 or 12, and the machine, a correction device 70 which can modify the data input to represent an offset in one or more of the co-ordinates X, Y with respect to the input data, the offset corresponding to the distance between the tools. As shown, the photo-electric line follower provides for each axis, a three phase, or two phase (quadrature) A.C. signal which, via synchro units (61, 62), Fig. 2 (not shown), (50), controls the respective flame cutter drives, carriages 18, 19 following the same contours in conjoint motion. The offset is provided by synchro (71), Fig. 3 (not shown), whose rotor is set to an anular position pre-set by stop (81) against which pin (82) fixed to the rotor bears, and representing the desired data offset, the synchro providing a corresponding phase shift in the A.C. signals from line follower to machine. During oxy-gas flame cutting, contacts (87-89, Fig. 2) are closed, cutting taking place without data offset. When a pulse line 91 or 92 on the drawing is encountered contacts 83-85 close, (87-89) opening, the so introduced offset representing the distance 23 in sense and magnitude between the cutter 21 and electropneumatic centre punch 22, the latter assuming a position to continue on the line of cut, cutter 21 having been switched off, punch 22 activated, by the detected line 91. Should the traced line not be perpendicular to the line joining cutter and punch, offsets are introduced in both X and Y co-ordinates. The offset may be introduced manually by switching in the synchro (71) or by adjusting the rotor angle from a zero phase value, to the desired offset position for centrepunching. Synchro (71) may be replaced by a quadrature resolver, or an electronic phase shifting circuit. The system may be used to provide offsets in X, Y, and Z for a three-axis machine, a single motor moving the rotors of three synchros to corresponding preset angles. The signals from line follower 11 are derived from synchros (46, 60, Fig. 2) driven by the motors driving the follower head (35).