GB1396747A - Size measuring device for workpiece of noncircular cross-section - Google Patents

Abstract

1396747 Grinding TOYODA KOKI KK 17 Aug 1972 [20 Aug 1971] 38448/72 Heading B3D [Also in Division G1] The diameter of a workpiece 10, Fig. 1, is measured electrically as it is ground by wheel 11; the diameter is compared with a preset value and the grinding operation is stopped when this value is achieved. In Fig. 1, the workpiece has an elliptical cross-section and its size is measured by diametrically opposed arms 16, 17 of differential transformer 15. As the ellipse is rotated during grinding a cyclic signal is given by the transformer as arms 16, 17 are moved to and fro. The signal is amplified and passed to a synchronous rectifier. The peak value of the rectifier output is stored in capacitor C 1 of holding circuit 34; a circuit 36 analyses the rectifier output and gives a first signal as the cyclic signal passes from minimum to maximum and a second signal as the cyclic signal falls again to its minimum. These two signals respectively discharge C 1 and gate the voltage on C 1 through an FET in a sampling circuit 35 to capacitor C 2 . The result of this is that the peak value of the cyclic signal, which represents the ellipse major diameter is passed from detector circuit 34 to sample circuit 35 under control of the timing circuit 36. When the output of sample circuit 35 reaches a predetermined value a Schmitt circuit 38 is triggered and relay 29 stops the grinding operation.