Abstract: The present invention is directed to a torque control with overspeed regulation and a method of controlling a hydrostatic drive for use in an auxiliary wheel drive of a vehicle which has both primary driven wheels and auxiliary driven wheels. The torque control permits maximum torque drive of the auxiliary wheels when the primary driven wheels slip but yet prevents overspeed operation of the auxiliary wheels. Preferably the torque control with overspeed regulation has both an aggressive control and a sensitivity control so that the auxiliary wheel drive can be selectively modulated with respect to the primary wheel drive.

Abstract: A steering system is disclosed for steering the wheels or tracks of a vehicle, the system having an optical control apparatus for controlling the steering of the wheels or tracks, the optical control apparatus being profiled optically so that, in the turn, the steerable wheels or tracks are steered around a common center.

Abstract: A system for indicating or recording the profile of a roadway is disclosed having a support which can be mounted on a vehicle to travel along the roadway, grade sensors mounted on the support for providing a proportional signal indicative of the elevation of selected points along the roadway, recording or indicating means for providing a proportional indication of the elevation of the selected points and means for stabilizing the support.

Abstract: A system is disclosed for maintaining, in a predetermined horizontal orientation, the support assembly for supporting an earth working tool to an earth working machine and comprises a cam surface and a cam sensor mounted between the support assembly and the machine wherein the cam sensor has a follower for following the cam surface to maintain the support assembly in its predetermined horizontal orientation. The system for maintaining the support assembly in a predetermined horizontal orientation is proportional.

Abstract: In a slope control system for the working tool of a motor grader or other earth working machine, the slope sensor used for controlling the slope of the tool is mounted on a resolving platform below the front axle pivot of the machine to provide anticipation of the deviations of the machine from the gravity reference. The attitude of the slope sensor is corrected by a factor related to the angle of the tool with respect to the longitudinal axis of the machine.

Abstract: A steering control system, for a land vehicle which is supported by right and left side propelling means for independently driving the vehicle, comprises a steering control apparatus for turning the right and left side propelling means for steering the vehicle and a frame distortion sensor which relieves any stress on the vehicle frame by controlling the speeds at which the left and right side propelling means drive the vehicle.