摘要 |
First and second arms are supported, rotatable to each other and in the shape of X, by a shaft. The lower end of the first arm is on the side of a scan gantry and rotatably supported on a base by means of a rotation fulcrum. The lower end of the second arm and upper ends of the first and second arms are supported by base and frame rails through movement fulcrums to be rotatable in relation to and movable along the rails. A tension spring is stretched between the second arm and a mounting frame to urge the mounting frame toward the scan gantry. Stoppers are arranged in the frame rails to prevent the movement fulcrums of the first and second arms from moving from their predetermined positions in the direction of their separating from the scan gantry. The first arms are rotated and erected by a hydraulic cylinder. The mounting frame is lifted along an arc whose center is the rotation fulcrum, with the first arms contacting the first stoppers, and then vertically lifted, with the second arms contacting the second stoppers.
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