| 摘要 |
PURPOSE:To make it possible to calculate the center of vibration by successively measuring light receiving time, by providing two light emitting parts hung by yarns so as to interpose a lower side measuring point therebetween and providing pendulums each having a light receiving element for receiving irradiated light in said light emitting parts. CONSTITUTION:When the aperture 7 of a pendulum unit 1 passes slits 16a, 16b, a light receiving element 8 outputs a light receiving signal and the operation part 27 in a lower unit 15 measures light receiving time by a signal P and a clock phi. When times allowing the aperture 7 to successively pass the slits 16b, 16a are set to t1-t4, the coordinates x0 of a lower side measuring point 14 are calculated from the values of the times t1-t4 because the distance between the slits 16a, 16b is preliminarily known as D. An operation part 27 calculates a shift amount xC on the basis of a prescribed formula and the calculated shift amount xC is displayed by a display device 28. By this method, measuring operation can be made simple and a measuring time can be shortened. |
