| 摘要 |
<p>A front axle (20) having wheels (21) at its ends, is turnably connected to an articulation unit (11) through a pivot shaft (23). In response to any unevenness such as bumps, pits and obstructions, the axle is turnable about the shaft within a clearance range between the axle and the articulation unit, such that either of the front wheels contact with the ground.</p> |
