GB1453842A - - Google Patents

Abstract

1453842 Tracer apparatus HYPER-LOOP Inc 5 Dec 1973 [11 Dec 1972] 56407/73 Heading G3N In tracer apparatus, in which machine drives are operated for X and Y co-ordinates of machine element motion, see Fig. 1 (not shown) in response to the deflection angle of a stylus in a tracer head, digital signals representing the cosine and sine of the deflection angle are formed and multiplied by a digital amplitude signal manually selected to represent a desired feedrate. The A.C. signal from the tracer head, itself activated by source 9, is processed in a circuit, Fig. 5A (not shown), to provide a ramp signal at point (118), whose crossings of a reference voltage level { ground } are detected to provide on line (144) pulses; synchronized to clock generator 56; whose timing represents the stylus deflection angle. The pulses on line (144) control gates (146) to open the path from the counter to read only memories 172, 178, for one count only, for each complete cycle of counts of the counter 160, the gated count value representing the deflection angle. Each read only memory is set to provide the sine of its input, inverters 176 ensuring that there appears on lines 180 a representation of the cosine. The outputs of the most significant bit stages of counter 160 are de-coded to define the quadrant of the angle, Fig. 3 (not shown). Binary multipliers 188, 182 receive the cosine and sine signals, and a desired feedrate signal, set via manual switches 60 to control multiplier 196, the multiplier outputs being the digital control signals, fed via leads (14, 16, Fig. 1) to the machine axis control servos including resolvers (28). The supply 9 may be a divided output of generator 56, and serves to reset, via units 147, 148, the counter 160, the tracer output signal being an A.C. signal of the same character as the supply 9, but phase shifted in accordance with the stylus deflection angle.