| 摘要 |
<p>PURPOSE:To allow monitoring of the missing of cable by passing infrared ray emitted from a light emitting element through the opposite sides of multiple rollers arranged between hauling machines(HM) in the cable laying direction to a light receiving element and laying a cable while confirming reception of infrared ray for each section. CONSTITUTION:A cable 1 is inserted from a cable drum into a culvert through a manhole. HMs 2 for feeding the cable 1 are disposed in the culvert at an interval of 30-50m. A light emitting element 20, e.g. an infrared ray emitting element, and a light receiving element 21 are arranged in the vicinity of the HM 2 and the light receiving element 21 is connected through an alarm line 23 with an alarm board 26 installed at one cable laying end. The cable 1 is laid straight so long as the HMs 2 are tuned mutually. When the cable 1 is removed from the roller 3, light emitted from the light emitting element 20 is blocked by the cable 1 and not received by the light receiving element 21.</p> |
