| 摘要 |
PROBLEM TO BE SOLVED: To provide an opening structure which is excellent in water catchment properties, which can block a malodor from an underground space, and which makes it unnecessary to open/close all of external and internal covers during light work.SOLUTION: An opening cover structure of an underground space structure, which is a double cover structure comprising external and internal covers 6 and 5, is configured as parent-child cover structures comprising a parent cover and a child cover, respectively. The external cover 6 is configured as a grating type, and the internal cover 5 is provided with a damper structure 34 and an exhaust pressure valve 29. The internal cover 5 comprises an internal parent cover of an inverted truncated cone-shaped side wall 20, and an internal child cover 21 corresponding to a bottom surface thereof. The internal parent cover is provided with the exhaust pressure valve 29, and the internal child cover 21 is provided with the damper structure 34.SELECTED DRAWING: Figure 1 |
