Articulated vehicle

Claim 1

An articulated vehicle comprising: (a) a front member having at least two axles, the forwardmost axle being steerable, (b) a rear member, connected to the front member by a pivotal joint, having at least one axle and an engine for driving that axle, (c) a first transducer for producing a signal representative of the angle between the steerable axle and another non-steerable axle of the front member, (d) a second transducer for producing a signal representative of the buckling angle between the longitudinal centerlines of the front and rear members, (e) comparator means for receiving the signals from the transducers and for producing a signal in the event that the actual buckling angle between the vehicle members is less or greater than a theoretical buckling angle, the theoretical buckling angle being determined by the signal from the first transducer, (f) two pneumatic piston and cylinder assemblies pivotally connected between the two vehicle members, the piston and cylinder assemblies being located one on each side of the pivotal joint and being responsive to the signal from the comparator for producing a torque about the pivotal joint to increase or decrease, as the case may be, the actual buckling angle between the vehicle members so that it approaches the theoretical buckling angle, and (g) a resilient pneumatic fluid within each piston and cylinder assembly for permitting variations between the theoretical and actual buckling angles, caused by roadway conditions, while constantly urging the actual buckling angle toward the theoretical buckling angle.