Abstract: An improvement in a working vehicle, such as a tractor, which includes a first frame part to which a steering wheel axle is coupled and a second frame part to which a second wheel axle is coupled with the frame part being pivotally interconnected to allow steering of the vehicle and wherein one of the wheel axles is swivelly mounted to its respective frame part to rock about a substantially horizontal axis so that one end of the rocking wheel axle is elevated when the vehicle is driven over uneven terrain.

Abstract: A control system and method for loading an engine driven apparatus such as an engine driven tractor having a plough the depth of which can be regulated by a suitable control system. The engine has a fuel injection pump which includes a maximum fuel feed limiting structure, a stop, and a structure for urging the maximum fuel feed limiting structure against the stop when an overload is imposed on the engine. Under the latter overload conditions the force with which the maximum fuel feed limiting structure is urged against the stop is detected by way of a force transducer such as a strain gauge or hydraulic pressure transducer, so that a signal indicative of the overload is produced and can be utilized for reducing the load on the engine. Thus, in the case of an engine-driven tractor which operates a plough, the latter signal can be utilized to raise the plough so as to reduce the load on the engine.