Automatic overrunning brakes are made up of the following components; overrun device, transmission unit and wheel brake. The legal requirements for testing and approval of these components are established under 71/320 EEC and more recently 2002/78/EC.

The automatic overrun brake system has been proven and established for caravans and trailers for decades. The simplicity of construction and robustness are distinct advantages. They react to load change and control the brakes automatically, without the necessary dependence or allocation to the towing vehicle.

The overrun device can be described as the control device of the overrun brake system. A draw-bar force is produced at the coupling point by reducing the speed of the towing vehicle. After the threshold level has been passed, the draw shaft is pushed in, thus actuating the overrun lever; the wheel brakes are then applied via the expanding clutch.

Brake Operation and Adjustment

ABS is recommended for the towing vehicle. Using ABS reduces the stopping distance at a speed of 80 khm/h from 50 m (without ABS) to 42 m with ABS. The steering and overall control of the car and caravan is also greatly improved.