| 摘要 |
PROBLEM TO BE SOLVED: To provide a gate which solves the problem that sewage flow-down is impeded when snow is repeatedly thrown into a manhole, where the amount of water flow is comparatively small, causing accumulation of snow mass since it takes time to melt the snow. SOLUTION: A roof gate 6 is provided on a downstream side of a bottom wall 3 of an underground drain sewer 3 immediately under a manhole 2 around a facility like a road in a manner that a base part of the roof gate can be raised at a horizontal shaft 5. A center part of an arm 12 provided with a balance weight 13 at an end thereof is swingably mounted on a shaft 11 in the middle part of the manhole 2 above the roof gate 6. An end part 7 of the roof gate 6 and the other end of the arm 12 are connected to each other by a wire 8. The roof gate 6 in its raised state secures a balanced state of the two in a state that the underground sewage of a predetermined water depth is secured in the underground drain sewer 3. COPYRIGHT: (C)2007,JPO&INPIT
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