Load support shifting vehicle

摘要

A vehicle with a driving track assembly and a pair of secondary driving and steering assemblies disposed on opposing lateral sides of the track. Each secondary driving and steering structure includes a ground engaging driving and steering structure that is preferably a ground engaging wheel. The driving track assembly includes an endless ground engaging track that drives the vehicle. The flanking driving and steering structures also engage the ground and are rotated to impart force to the vehicle. A steering device is operatively connected to the secondary driving and steering assemblies. the steering device control operation of the secondary driving and steering assemblies so as to affect a vehicle steering operation wherein the ground engaging driving and steering structures are operated to turn said vehicle with respect to said vehicle driving and steering direction. Preferably, the force imparted to the vehicle by one of said ground engaging driving and steering structures is greater than the force imparted to the vehicle by the other of the ground engaging driving and steering structures, thereby causing the vehicle to turn with respect to the vehicle driving and steering direction. Preferably, the steering device control is operable to transfer a substantial portion of the load support from the central driving track assembly during straight ahead movement onto the secondary driving and steering assemblies during turning movements.