| 摘要 |
<p>The chassis has front and rear axes (10a,10b) each supporting two wheels or two pairs of wheels, at least one of which is used for steering. A common control unit (SE) is used for driving the wheels in respective front and rear drives (MV,MH), for deflection of the steered wheel axis (10a) and for raising and lowering support packs (30) adjacent each wheel or wheel pair for supporting the chassis in a fixed position. The control unit (SE) responds to operation of the direction selection control (35) to cause the packs (30) adjacent the steered wheels (27a,27b) to be lowered so that the wheels (27a,27b) themselves are raised before being tuned. The operation of the drive switch (34) automatically causes the support jacks (30) to be raised so that the wheels are in contact with the ground.</p> |
