Anti-jackknifing device with friction brake for articulated motor vehicle

Claim 1

In an antijackknifing device for a motor vehicle having two articulated units with a friction brake therebetween having a hydraulic brake actuating cylinder, the improvement comprising hydraulic control means for controlling the torque applied by the brake including: first means comprising a hydraulic sensor actuating cylinder with two working spaces for sensing the jackknifing angle between the two units; a three-position four-way reversible valve having a first port connected to a first actuating space of the sensor actuating cylinder, a second port connected to the second actuating space, a third port connected to the fourth port in a loop with a check valve preventing flow in the direction from the third toward the fourth port and the hydraulic brake actuating cylinder connected between the third port and the check valve, wherein the valve in its first position connects the first and third ports and the second and fourth ports and in its second position connects the first and fourth ports and the second and third ports; means for sensing the steering angle; and means for determining the desired jackknifing angle for the sensed steering angle and in response to the deviation of the actual jackknifing angle from the desired jackknifing angle for actuating the valve into its first position when the actual jackknifing angle represents that the two units of the vehicle are overdriven in the clockwise direction and into its second position when the actual jackknifing angle indicates that the two units of the vehicle are overdriven in the counter-clockwise direction, whereby the brake will act to prevent a worse overdriven condition.