| 摘要 |
PURPOSE:To obtain a highly reliable device which can specify a circumferential detection position by providing a detection head internally with its rotation detecting means. CONSTITUTION:The rotation detection part 9 fixed in the detection head 51 detects the quantity of rotation of the head 51. Here, a disk 10 is held by supports 15a and 15b, etc., and rotate freely, and a weight 11 is fitted and faces in the gravitational direction at all times, thereby stabilizing the disk. The supports 15a and 15b are fixed to the head 51 and rotates as the head rotates, so that the position relation with the disk 10 varies. The variation can be detected by reading optical marks (d and e) of plural tracks 12a-12c of the disk 10 by light projectors 16a-16c and photodetectors 17a-17c fitted to the supports 15a and 15b. Then the outputs of the photodetectors 17a-17c are shaped by a photodetecting circuit 19 and outputted to an external signal processing means, etc., so that the internal surface detection signal of a pipe P to be inspected and the position in the gravitational direction are made to correspond to each other.
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