| 摘要 |
PROBLEM TO BE SOLVED: To install a lid body to a joint metal with single operation by forming a plate-shaped joint metal plate to an octagonal shape in plan view, providing a lid body attaching portion to an octagonal opening in plan view and inserting and fixing a lid body having the shape almost as same as that of the opening to the attaching portion for lid body. SOLUTION: Laterally long metal plates 3, 3 are folded and bent and formed to an octagonal shape in plan view by using two plates as one set. Next, a gap members 4, 4 made of wires or the like are interposed in a portion to be connected together by overlapping both the ends thereby forming a gap, and the metal plates 3, 3 are fixed by welding or the like. The lid body 6 is constituted with a metal plate having the shape almost the same as the octagonal opening portion 2a of the joint metal 2. A central portion of a pair of sides facing is respectively folded and bent downward thereby forming bent portions which are then inserted to gaps formed by interposing a gap member 4. Thus, the lid body can be easily attached to the joint metal by single operation and the lid body can be definitely fixed to the joint metal.
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