The cold rolling mill Risse + Wilke Kaltband GmbH in Iserlohn produces metal sheets of different thicknesses and qualities. The unmachined steel strips, wound into coils, are repeatedly rolled by means of cold rolls until they have the required material properties. Then saw blades, clutch plates and other metal parts are punched from them.

Heavy forklift trucks transport the coils from the storage location to the rolling stand and back. Enormous masses have to be moved: The forklift trucks and their freight can weigh up to 30 tons. One steel sheet roll alone can weigh more than 12 tons. This means that the trucks' braking distance is quite a bit longer than that of a regular car.

Caution when maneuvering

Particularly when reversing, e.g. after the coil has been picked up from the storage location or the rolling stand, the drivers need to be very cautious to avoid collisions with other forklift trucks or persons when turning into the lane. They do not only have to keep an eye on the rear area of the vehicle, but must also ensure that the carrying ram, with its load swaying from side to side, does not collide with anything.

Florian Rolf, production manager at Risse + Wilke, explains the enormous challenges the drivers have to face: "The forklift trucks are equipped with aids such as mirrors and cameras. Nevertheless, the drivers must still be fully alert at any time, they must always have 360° vision and monitor their load and where they are going. At the same time they have to be aware of what is happening around them, e.g. colleagues and contractors crossing their path. Otherwise it can easily come to critical situations which we want to avoid."

Collision warning system

In order to avoid such critical situations, the sensor specialist ifm from Essen has developed an automatic collision detection system.By means of a 3D camera, the system permanently monitors the rear of the forklift truck and gives the driver visual and acoustic feedback. Depending on the configuration level, the assistance system can even stop the vehicle, if necessary.

All obstacles are reliably detected. Thanks to a special classification of reflective materials, e.g. reflective vests or clothing, the collision warning for persons can be given priority over other objects. This increases the safety of persons and leaves the driver enough time to slow the truck down and stop in time. This provides maximum safety when maneuvering.

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