| 摘要 |
PROBLEM TO BE SOLVED: To prevent parallel movement of an iron cover by making an opening/closing part that of lock type, making a lock unlockable unless a turning spindle for opening/ closing the iron cover is turned at a specified angle or more, and enabling the cover to rise together with an arm for floating the cover by pressure of water at the time of flood while enabling the cover to be fitted by its weight at the completion of flood. SOLUTION: An iron cover opening/closing turning spindle 4 is separated from a gouge 3. Only when the spindle 4 is turned by hand at the angle of 15 degrees or more to parallely move a meshing male lock 6, meshing of the lock 6 is released from a female lock 5 integrated with a receptacle frame 2, and an iron cover can be made openable/closable by gouging the gouge 3. Accordingly, when water of such as heavy rain comming in exceeds the flow-down capacity of drainage poipe 12, an arm for floating the cover 1 is raised together with the same by the amount corresponding to a gap between the male and female lock parts 5, 6 until an iron cover floating arm stopper 9 abuts on an arm stopper receptacle 10, and thereby the water exceeding the capacity is overflowed from the raised gap. After the completion of flood, the cover is fitted to the receptacle 2 by its weigt.
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