Emam, M., "A Safety Mechanism for Agricultural Tractors," SAE Technical Paper 2012-01-1180, 2012, doi:10.4271/2012-01-1180.
This paper presents a safety mechanism that is supposed to be used to enhance in the agricultural tractors. A tractor instability situation may be occurring when drawbar force becomes large enough to cause no load (weight) on its front axle. This endangers the tractor stability and the tractor will be overturned rearward. The proposed tractor safety mechanism is based on monitoring the location of tractor center of gravity and progressively shifting forward in a dead weight to counteract for the effect of tractors front lift-up.A laboratory tractor model has been developed in such a way that the lift of its front is sensed and accordingly a mechanism that shifts a movable dead weight ahead to the front a distance that automatically ensures its longitudinal stability. Such arrangement provides a solution that practically ensures longitudinal tractor stability in the situations when maximum drawbar-pull is suddenly developed. This dangerous situation practically occurs when a tractor driver fully presses the throttle to encounter the increasing resistance to tractor motion. A computer controlled system that includes an operating unit, a control unit, and a detection unit has been designed and built, and the results of experimental investigation are presented. The results proved that mechanism and the control system acted successively and that the tractor model was not fully lifted away from ground.