| 摘要 |
PURPOSE:To prevent a road surface from being damaged when a tire rolls on a paved road by forming the longitudinal groove for spikes onto a cushion corresponding to a tread and arranging hydraulic cylinders at prescribed positions in the groove and allowing the spikes to appear and disappear by the operation of the cylinders. CONSTITUTION:Longitudinal grooves 6 for spikes which are opened onto a tread 2 are formed in the circumferential direction on the surface layer side of a cushion 3 corresponding to the tread 2 of a tire body 1. In said longitudinal groove 6, hydraulic cylinders 5 are arranged in the vertical state at a prescribed intervals, and are advanced and retreated by controlling the supply and discharge of the hydraulic pressure into the upper and lower side chambers 7a and 7b divided by a piston partitioning wall 7 inserted inside. A piston rod 9 whose top edge is formed into the spike 8 is fixed onto the piston partitioning wall 7, projecting in a airtight state outside the cylinder 5. Further, an annular rubber band 12 is fitted into the space formed over the cylinder hole 17 in the longitudinal groove 6, and the piston rod 9 is inserted into a longitudinal hole 12a formed on the rubber band 12.
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