| 摘要 |
<p>The drive wheels (12) and drive shaft (10) of the tractor mechanism are constructed to eliminate the possibility of assembling the mechanism with drive pins (14) on opposing drive wheels (12) laterally misaligned. Also disclosed are mechanisms for stabilizing the position of a drive wheel carriage (54, 56) relative to a drive shaft (70, 100) without the need of a secondary shaft. <IMAGE></p> |
