| 摘要 |
PROBLEM TO BE SOLVED: To improve the efficiency and safety of cutting work by providing a frame having a band saw installed thereto in such a manner as to be capable of rising and falling to the upper position of a material to be cut by a hydraulic jack, and providing a discharge flow regulating means in the working fluid discharge passage of the hydraulic jack to regulate the self-weight descending speed of the frame. SOLUTION: In the cutting of a material to be cut 5 such as a pipe used in a nuclear power plant, a discharge flow control valve 91 is opened, and the working fluid within a lifting hydraulic jack 83 and a working fluid discharge pipe 87 is discharged with regulation to lower the hydraulic jack 83. A band saw drive part 60 is also driven. According to this, the weight of a band saw body part 40 acts on a band saw 45, and the band saw 45 is moved orthogonally to the axial direction of the material to be cut 5 to cut the material to be cut 5. At this time, according to the shape of the material to be cut 5, a cutting force by a fixed pressure according to the weight of the band saw body part 40 is generated in the band saw 45, and the material to be cut 5 is cut by this cutting force.
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