| 摘要 |
PURPOSE: A trolley is provided to freely change its direction and freely move in a narrow space by touching only a second wheel on a road surface when the direction is changed. CONSTITUTION: A moving portion(30) comprises first wheel portions(31) to be moved frontward and backward and second wheel portions(32) to be moved leftward and rightward. The first wheels are touched with the road surface and the second wheels are separated from the road surface at a certain height. In changing its direction, only the second wheels are touched with the road surface by the movement of a piston rod in a hydraulic cylinder. Thereby, a trolley moves in a narrow space and changes its direction freely.
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