Paul Nutzfahrzeuge increases the Unimog's efficiency in alpine mountains through self-steered trailing axle and all-wheel steering

Premiere – first conversion of the Unimog U 530 in Euro-6 configuration for the community of Lech am Arlberg, Austria:

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• Lech am Arlberg receives the first Unimog U 530 with airsuspended self-steered trailing axle and all-wheel steering converted by Paul Nutzfahrzeuge

• Three axles provide an increased payload capacity for snow transportation in wintertime and for bulk material transports during the other seasons

• All-wheel steering increases maneuverability in the town center

• Equipment options with rotary snow plough, mowing equipment and roll-off tipper body

• High versatility and flexibility: no support vehicles are necessary

• Increased efficiency, profitability and environmental compatibility

Vilshofen on the Danube/Lech am Arlberg. The community of Lech in Vorarlberg in Austria has received a powerful all-round vehicle for allseason application in winter and summertime. For this purpose, Paul Nutzfahrzeuge has equipped a Unimog U 530 with a steered and airsuspended trailing axle as well as an all-wheel steering system. This new generation Unimog is the most powerful professional implement carrier of its kind. The vehicle was handed over on 4 February 2016 by Gerhard Netbal and Paul Schmidhuber from the Pappas Group and Martin Bauer, head of the marketing department of Paul Nutzfahrzeuge GmbH to Ludwig Muxel, mayor of the community of Lech am Arlberg and Günter Schneider, head of the municipal building yard of Lech am Arlberg.

For many years now, Paul Nutzfahrzeuge is an established specialist for the installation of self-steered trailing axles into trucks and Unimog vehicles. On behalf of the Pappas Group, for the first time the Lower Bavarian specialist for modified vehicles has now fitted a Unimog U 530 of the innovative Euro-6 generation with a self-steered trailing axle and the associated steering hydraulics and steering electronics for the community of Lech am Arlberg. The special equipment increases the gross vehicle weight of the off-road all-wheel drive vehicle to 25 tons. The range of applications for mowing and snow clearing operations and thus the allseason usage is considerably enhanced by the increased maneuvrability and the increase of payload to 14 tons. For example, the use of costintensive support vehicles to remove mowed grass or cleared snow is no longer necessary thanks to the conversion measures carried out in the production plant of Paul Nutzfahrzeuge at Vilshofen on the Danube. Thereby, however, these measures not only increase the environmental compatibility but also enhance the well-known high efficiency and flexibility of the Unimog implement carrier even more. This is an important factor because it increases the Unimog's suitability considerably when working in the narrow lanes and steep mountain passes of the Austrian alpine region at the Arlberg.

"With this new three-axle Unimog implement carrier we have a highly efficient working tool at our disposal that allows for a broad range of use in each season and thus for a quick and seasonally independent action“, says Günter Schneider, head of the building yard of the Lech am Arlberg community. "It enables us to present a cultivated landscape with well-kept public gardens, meadows and parks, as well as free driveways for residents and visitors alike at all times of the year. This increases the attractiveness of our community considerably", adds Ludwig Muxel, mayor of Lech am Arlberg.

Third axle increases payload capacity and versatility

The three-axle Unimog U 530 converted by Paul Nutzfahrzeuge provides an output of 220 kW/299 hp from its Euro-6 engine and a long wheelbase of 3,900 mm. It has a payload capacity of remarkable 14 t, including the Meiller tipper body or rather transport container. First of all and as a base for the conversion the tight space conditions on the vehicle had to be expanded. Thus the standard vehicle frame overhang was extended from 1,000 mm to 2,250 mm to accommodate the third axle and a roll-off tipper body with a length of up to 5,000 mm. The installation of an air-suspended self-steered trailing axle with drum brakes and a gross axle weight rating of 9 t increases the Unimog's gross vehicle weight in combination with the front axle (axle weight rating of 7.5 t) and the first rear axle (axle weight rating of 9 t ) to a total of 25 t. The air suspension of the self-steered trailing axle is controlled via the bounce distance of the drive axle. The axle guide is made by means of suspension arms and track control arms as well as steering stabilizers. The wheels on all axles are fitted with single tires of the 385/65 R 22.5 dimension.

Extremely high maneuvrability is the decisive factor

An important factor in the skiing areas of the Vorarlberg region and therefore in the community of Lech am Arlberg as well is an extremely high maneuvrability and a safe getting through under the prevailing and often extremely limited space conditions. With the installation of steering hydraulics plus steering electronics for the trailing axle it has been integrated into the all-wheel steering which considerably increases the maneuvrability of this new Unimog vehicle conversion. Thereby arise expanded fields of application on mountain roads with limited road width and in the narrow village and town center areas of the Lech community. Especially when it comes to efficient snow clearing in winter service operation this proves to be an enormous advantage.

The types of steering can be selected from the newly installed control panel within the driver's cab. Up to a maximum traveling speed of 15 km/h allwheel steering is possible. Depending on the individual steering angle of the front axle, the first and second rear axles are steered in the opposite direction of the front axle's steering direction. This provides an improved maximum maneuvrability when working in narrow places. Diagonal steering is also possible, this is the so-called "crab steering". In this process, the two rear axles follow the steering direction which is defined through the front axle. This facilitates a safe operating process, particularly when working at locations on a slopy hillside terrain and when carrying out rolling processes or compacting works. If all axles are steered in the same direction, the vehicle can be offset almost parallel. Of course, the two rear axles can also be steered manually and thus completely independent of the front axle.

Up to a speed of 40 km/h, the trailing axle is steerable. For safety reasons, there is a complete locking at higher speeds. As a result it is only activated for straight running and directional stability. Up to 30 km/h and for a maximum of three minutes a starting assistance can be added on, which increases the traction for starting on gradients.

Maximum output for transport operations and snow clearing

After conversion the new three-axle Unimog implement carrier is predestinated for the intended use with mowing and mulching attachments in summertime and with a powerful Westa rotary snow plough in wintertime. At the front of the vehicle an attachment plate has been mounted for the attachment of the rotary snow plough and various mowing or mulching attachments which are driven by the front power take-off installed exfactory. If no implements have been mounted at the front a ballast weight of approximately 1,000 kg is attached to ensure the required front axle load and thus guarantee an excellent steering behaviour.

The increased payload capacity enables the three-axle Unimog U 530 to take over transport operations as well and, for example, handle the removal of the cuttings and of snow with up to 80 km/h in a single working process. Thereby it dispenses with the otherwise cost-intensive and time-consuming use of a support vehicle for transport operations. At Lech it will be used in summertime for the transport of mowed grass and wood chips to the surrounding biogas plants or the removal of sewage sludge to the disposal plants. In wintertime the rotary snow plough blows the masses of snow directly into the container. When transporting the containers the roll-off tipper body provides an enormous saving of time, and particularly in wintertime it speeds up the snow clearing operations to a high degree. That way, containers filled with snow can be set down and empty containers can be picked up which allows the Unimog to continue its work without delay.

To protect the vehicle from damages, Paul Nutzfahrzeuge has installed a special underride guard at the rear of the vehicle. Due to the total length of the vehicle including the container the underride guard is retractable. This prevents that the bulk material damages the underride guard during tipping when unloading the vehicle.

The Meiller RK 14,5 roll-off tipper body which is firmly fixed to the chassis frame of the vehicle has a container length of 5,000 mm and a tipping angle of approximately 54 degrees. Paul Nutzfahrzeuge has installed the hydraulic drive via the engine power take-off and enabled an exact control via the pump of the load-sensing hydraulics which has also been installed at Vilshofen. The tilting movements are controlled from the driver's seat via joystick control in a safe and comfortable way and protected from weather effects.