| 摘要 |
PROBLEM TO BE SOLVED: To easily lift and close a cover which is in contact with the ground surface with its reverse side up. SOLUTION: The cover of an underground structure is connected to a bearing frame by a hinge or a chain, and is opened by turning the cover by about 180 degrees. The cover has, on its reverse face, a handle and/or an engaging member to be engaged with an opening/closing tool. COPYRIGHT: (C)2005,JPO&NCIPI
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