| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the possibility of the damaging of a road surface or the like by a hook member and the damaging of the hook member when a cover body closing the opening of an underground structure is turned for opening the cover body. SOLUTION: The cover body 12 closing the opening 13 is brought to a locked state, and the hook member 15 brought to the state in which the locked state of the cover body 12 is released when required movement is applied to the cover body 12 by external operation is installed on the side of a frame body 11.
|
