| 摘要 |
PURPOSE:To put in and out spikes according to the presence of ice and snow on a road surface to prevent slip and damage of the road surface by moving forward and backward a slider having a slant wedge surface between a case and a spike member by a drive member made of shape memorizing alloy. CONSTITUTION:When ice and snow are absent on a road surface, a press member 17 made of shape memorizing alloy extends to press a slider 13 against a restoring member 18. Thus, a root 11 of a spike 7 bears against a flat slide surface 14 of the slider 13 and the spike 7 is withdrawn from the tread surface 4 of a tire 3 by a returning spring 22. Thus, the road surface is prevented from damages. On the other hand, when ice and snow are present on the road surface, the press member 17 contracts so that the slider 13 is pressed in the direction reverse to said one by the restoring member 18. Thus, the root 11 of the spike 7 bears against the wedge surface 15 of the slider 13 to project the spike 7 from the tread surface 4 of the tire 4 against the returning spring 22. Thus, the slip can be prevented. |
