| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cable accommodation duct inner diameter measuring apparatus capable of accurately measuring the condition of deterioration occurring inside a duct even for an underground buried small-diameter cable accommodation duct having a small aperture or an underground buried small-diameter cable accommodation duct in which cables are installed and which has a small aperture. <P>SOLUTION: A laser irradiation device 40 utilizes laser emission to emit a light ring in a circular center shape within a cable accommodation duct, and a small-diameter camera 20 images the optical ring. A laser irradiation device installation section 30 and a small-diameter installation section 10 include duct interference canceling parts 50a and 50b that are used to pass through a step or a gap that is generated in a joint of the cable accommodation ducts, and cable interference canceling parts that are used to cancel friction caused by a contact between cables accommodated in the cable accommodation duct and a measuring apparatus body. The small-diameter camera installation section 10 includes an adjustment part 60 that makes adjustment such that the light ring assumes an optimal size within an imaging screen when the small-diameter camera 20 images the light ring. <P>COPYRIGHT: (C)2013,JPO&INPIT |
