| 摘要 |
PROBLEM TO BE SOLVED: To open and close a steel lid installed on the ground, by a bar with a T-shaped end which is normally used for a bar hole bored, without using a special bar or an opening tool for opening the lid by releasing a lid floating prevention device, the lid having a bag-shaped chamber formed of both a bag-shaped piece covering the lower portion of the bar hole and the peripheral wall of the receiving frame. SOLUTION: The steel lid installed on the ground comprises a circular receiving frame; a lid for opening and closing an upper opening of the receiving frame; a hinge for connecting the receiving frame to the lid; a bar hole cut in the peripheral edge of the lid opposite to the hinge; and a bag-shaped chamber formed of both the bag-shaped piece covering the lower portion of the bar hole and the peripheral wall of the receiving frame. A floating preventer is slidably provided on the inner surface of the receiving frame. A lock projecting from the back of the lid is engaged with the floating preventer to obtain a device for preventing the floating of the steel lid. COPYRIGHT: (C)2004,JPO
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