Programmgesteuerte Werkzeugmaschine mit zwei wahlweise verwendbaren Steuerungssystemen

1, 021, 414. Numerical control of machine tools. MASCHINENFABRIK HEID A.G. Oct. 1, 1964 [Oct. 1, 1963], No. 40007/64. Heading G3N. In a numerical control system for a machine tool, travel data is programmed in incremental steps, or, where the desired position is to be of greater accuracy than that afforded by the travel indicator, by the selection of rigid stop members. As shown, travel and circuit data read by a perforated strip scanner 1 is fed to a control unit 3. Directional data is fed to a positioning member 5 for a carriage 22 and desired travel data, through a store 7, is applied to a comparator 9. Carriage movement is sensed by an indicator 10 sending increment pulses to a backward and forward counter 12 supplying actual travel data to the comparator 9. At coincidence between the desired and actual travels a signal is sent through a switch 15, conditioned by unit 3, to the unit 3 to stop positioning member 5 and step the scanner 1. When a travel position is required to be of higher accuracy than that attainable by the incremental system, the scanner 1 conditions the control unit 3 so as to change-over switch 15 so that the travel terminating signal is derived from a rigid stop member 21. For automatic zero-positioning a coincidence signal from the member 21, through a delay device 32, zeros the counter 12. The rigid stop member 21 incorporates a pair of switches the first of which reduces the speed of a positioning motor and the torque of a driving clutch, the second switch open-circuits the clutch when the carriage 22 strikes the rigid stop member.