| 摘要 |
PURPOSE:To measure the displacement between points without receiving the effect of the extension of a wire, by a method wherein it is detected that the marker provided to the wire stretched so as to pass a plurality of points passes each point and the moving distance of the market between respective points is calculated. CONSTITUTION:Rollers 11 are provided at the origin O and measuring points A, B... and a loop like wire 12 is trained over said roller and a metallic marker is provided to one place of said wire 12. The wire 12 is driven by motor 13 and the send-out quantity of the wire 12 is detected by a rotary encoder 14 to be converted to a pulse signal. Further, approximate switches 15 are arranged at the points O, A, B.... When the switches 15 detect that the market passes the point O, A, B, the difference between the number of pulses of the encoder 14 during a time when the marker moves between the points O, B and those of the encorder 14 when said marker moves between the points O, A is calculated to make it possible to measure the distance between the points A, B. By this method, the distances between the points are measured plural times and, when the differences between them are calculated, the displacement quantities between the points A, B... can be calculated.
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