| 摘要 |
PROBLEM TO BE SOLVED: To provide a fall preventing device for a manhole, having excellent mechanical strength and effectively preventing fall of a tool and an instrument, facilitating recycle, and further preventing corrosion in a short time. SOLUTION: This fall preventing device for the manhole 10 is supported on a receiving frame 2 substantially horizontally under a manhole lid 1 to be raised. The device includes: a ladder member11 supported on the receiving frame 2; arm parts 12, 13 formed on both right and left sides of one side of the ladder member 11 and inserted in right and left cylindrical parts 2d, 2e formed inside the receiving frame 2 in erecting the ladder member 11; locking members 15, 16 for locking the ladder member 11 in the state of being supported on the receiving frame 2 substantially horizontally; and a releasing member 19 for releasing the locking state of the locking members 15, 16. The ladder member 11 is formed of cast iron, and covers the substantially whole area of an opening inside the receiving frame2. COPYRIGHT: (C)2004,JPO
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