| 摘要 |
PROBLEM TO BE SOLVED: To easily release a manhole hanging tool of a self-weight internal-expansion type manhole hanging tool by automatically releasing the hanging tool by the self weight. SOLUTION: The manhole hanging tool 1 comprises a plurality of link arms 11 which are connected between each upper arm 8 and each pressing member 10 in an interlocking manner so that each pressing unit is moved outwardly in the radial direction of a manhole block 2 as a movable cylindrical body 7 is moved upwardly and each pressing unit 9 is moved inwardly in the radial direction of the manhole block 2 as the variable cylindrical body 7 is moved downwardly, and a locking means 26 to position the movable cylindrical body 7 at a lower position when the movable cylindrical body 7 is moved downwardly, and each pressing unit 9 is separated from an inner circumferential surface of the manhole block 2 in a non-hanging state. COPYRIGHT: (C)2004,JPO&NCIPI
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