Abstract: A anti-jackknifing device for a motor vehicle having two articulated units with a friction brake therebetween has a hydraulic control means for controlling the torque applied by the brake. A hydraulic sensor activating cylinder with two working spaces senses the jackknifing angle between the two units. A three-position four-way reversible valve is connected to the hydraulic brake activating cylinder, between a third port and a check valve and the valve in its first position connects its first and third ports and its second and fourth ports and in its second position connects its first and fourth ports and its second and third ports. A steering angle sensor is provided which determines the desired jackknifing angle therefor.

Abstract: A jackknifing limiting device for articulated motor vehicles in which the vehicle has a front section and a rear section which are connected by a hinge therebetween, the device acting to limit the angle between the front and rear sections when the vehicle is turning, the device comprising a pair of hydraulic cylinders flanking the hinge and connected between the front and rear sections and a reservoir containing hydraulic fluid for the cylinders. Respective pressure regulating valves are connected between the reservoir and the cylinders and open unidirectionally toward the reservoir, with respective solenoid stop valves connected between the regulating valves and the reservoir, the stop valves being normally open. Respective check valves are provided in respective bypass lines connected between the reservoir and the cylinders, the check valves opening unidirectionally toward the cylinders.