| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a prefabricated joint with a spring unit confirmation win dow, through which the states of spring units can be observed visually from the outside. SOLUTION: A rubber stress relief cone 21 are combined with an epoxy unit 11 and pressed against the epoxy unit 11 by spring units 41, and the entire construction is covered with a protective tube. One or a plurality of inside observing windows 52a made of a transparent material are provided on end parts 52' of the protective tube. Through the inside observing windows 52a, the conditions of the spring units 41 are made visually observable from the outside. The inside observing windows 52a may be covered with an opening/ closing cover to protect their transparent material parts from external injuries. As other observation method, scales by which the set lengths of the springs can be seen can be formed on the inside observing window 52a or the end parts 52' themselves are made of transparent hard material, and the observation windows are set at the parts of the end parts 52' and conductive paint or metal foil is applied to the other parts of the end parts 52'.</p> |
