| 摘要 |
PROBLEM TO BE SOLVED: To provide a new auxiliary jack for hoisting a cover frame body of a manhole, which can greatly reduce a construction time needed for a construction method of removing the cover frame body of the existing manhole, and can consequently further reduce the period of repair work for the manhole. SOLUTION: This auxiliary jack for hoisting the cover frame body of the manhole is used for the construction method for removing the cover frame body of the manhole through a step of breaking an outer-peripheral-section road surface of the cover frame body of the existing manhole. The auxiliary jack is equipped with a base plate 42, three engaging leg parts 44 which are arranged on the downside of the periphery of the base plate 42, a triple-head cylinder 47 wherein three cylinders for radially expanding the engaging leg parts 44 in a lower end position are radially provided, and a hydraulic pump 48 for expanding/contracting the triple-head cylinder 47. An engaging pawl 46 is provided on the outside of the lower end of the main body of the engaging leg part 44, and the lower ends of the main body of the engaging leg part 44 are mutually connected by means of a coiled spring 50. COPYRIGHT: (C)2006,JPO&NCIPI
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