| 摘要 |
<p>The bicycle rear wheel (4) carries a supplementary chain wheel (28). This wheel is connected by a chain (27) to a shaft (19) carrying two driving wheels (21) for two endless tracks (22) which have notched belts on their two faces. The shaft is constituted from one of two frame cross-members formed from two triangular parts (15,16,17) pivoted on the rear wheel axle (18). The triangular frame constitutes a support which can be tipped around the axle (18) to occupy a rest position, in which it is raised and held fastened to the rear fork (1b) of the bicycle frame. When the frame is tipped into a working position the endless tracks are interposed between the wheel, then slightly raised, and the ground. <IMAGE></p> |
