| 摘要 |
PURPOSE:To prevent mud and sand from penetrating, simplify the construction and facilitate assembly, by slidably inserting a frame into a hollow part. CONSTITUTION:A slidable part of a frame member 2 is enclosed by a frame member 1, so that earth and the like are prevented from penetrating into the slidable part. The frame member 2 is prevented from rotating with respect to the frame member 1, through notched grooves 15, projected parts 17, a cylinder tube 7, retaining members 18 and flanges 21, so that an idler 6 can be advanced and retracted in a proper pose. In addition, the frame member 1 and the frame member 2 can be disconnected from each other by detaching the flanges 21 and taking out the retaining member 18 through ports 18, so that the frame 2 can be detached easily. Accordingly, disassembling and assembling operations are facilitated. |
