| 摘要 |
PURPOSE:To detect the contact of two bodies highly sensitively, by measuring the potential difference between the conductive body and the ground in the two bodies, and utilizing the change in the potential difference caused by an electromotive force when the two bodies having a relative speed are contacted. CONSTITUTION:Since the main body of a grinding plate is grounded, a table 4 is at a ground potential level. A conductive material to be ground 2 is electrically insulated from the table 4 by an insulator 3. At the instant a rotary grinding stone 1 is contacted with the material to be ground 2, an electromotive force is generated at the contact point between the grinding stone 1 and the material to be ground 2, and the potential difference is generated between the material to be ground 2 and the ground. The potential difference across a measuring impedance 13 in a contact detecting and judging circuit 5, which is connected between the material to be ground 2 and the ground, is amplified by an amplifier circuit 14 and compared with a reference voltage Vref in a comparator 16 through a waveform shaping circuit 15. Thus the presence or absence of the contact is judged. |
