摘要 |
Device includes a sprung (1) drive shaft carrying driving wheels and a running axle (2) on which running wheels are suspended. A first lever (3) operating between the running axle and the spring assembly (1) of each driving wheel raises and lowers the running axle by a second lever (5). The second lever has surfaces (5a-5j;6,7) located at distances from the fulcrum (10) of the second lever. The surfaces are arranged to be turned by the operating device (8) about the fulcrum. |