An unusual construction vehicle presents a challenge for a chassis specialist – especially when it sets new standards in the construction industry as part of the Cifa Spa product line. Paul Nutzfahrzeuge has successfully converted a four-axle dumper chassis to a seven-axle chassis for the Italian concrete equipment manufacturer. Thanks to five steered axles and a turning circle of about 33 m, the heavy-duty giant, with a permissible gross vehicle weight (GVW) of 75 t, can maneuver easily in confined spaces. The chassis will be used as the carrier vehicle for the new Cifa K80H concrete pump from the Carbotech series - a world first with the longest boom available in Europe. The chassis and its spectacular boom, which has already entered the Guinness Book of Records, will celebrate its world premiere at the bauma 2013 trade fair in Munich and be on display at the open-air exhibition area of Cifa Spa (F9, Booth No. 905/2).
"We are proud of the result of our outstanding cooperation with the Cifa Team," states Reinhold Grösser, Managing Director and head of the Special Trucks and Chassis unit of Paul Nutzfahrzeuge GmbH. "This order cements our position as an internationally recognized specialist and places us at the forefront in the market for special-vehicle applications in the highest payload range."
Stable base for boom with record length of 80 meters
The comprehensive design know-how of Paul Nutzfahrzeuge ensures reliable transportation and operation of the new Carbotech concrete pump, the 80 m length of which is divided into seven folding sections. Completely new: The uppermost four elements are manufactured from a strong yet weight-reducing carbon-fiber mixture. The chassis guarantees the required stability in its prime field of use, the building construction and civil engineering sector.
A 2.5 m wide Mercedes Benz Actros 4160 K 8x6 four-axle dumper chassis with a 4,500 mm wheelbase and a short S-cab was ultimately selected for the carrier chassis. In Passau, it was converted in only 12 weeks into a seven-axle chassis in the Actros 7561 14x6/10 configuration with an overall length of 14.99 m, a high engine output of 449 kW (610 HP), a reduced overall height of 3,035 mm and a chassis weight of only 17 t. The GVW of 75 t provides a payload of 58 t, thus permitting installation of the heavy K80H concrete pump. In Germany, on-the-road use of the vehicle is allowed with a special permit under the German Road Traffic Licensing Regulation (§ 70 StVZO).
Three additional axles for heavy-duty use
Extension of the wheelbase to 7,400 mm was accomplished at Paul by installing a third steered axle with air suspension at the front as well as two liftable steered trailing axles at the rear of the vehicle. The third front axle is a standard Mercedes Benz product and is steered by means of a mechanical connection to the first and second front axles. The technically permitted axle load is thus distributed over three steered front axles with an axle load of 9 t each. In addition, there are two rigid rear axles with an axle load of 13 t each and the two steered trailing axles with an axle load of 12 t each. The trailing axles manufactured by BPW are steered electrohydraulically as a function of the front axle steering angle as well as the travel speed. The lift mechanism is activated automatically as soon as the signal to extend the support legs is generated.
The engine output is transmitted to axles 1, 4 and 5. The tire size used on each front axle is 385/65 R 22.5. The rigid rear axles feature dual tires of size 315/80 R 22.5, while the two trailing axles use tire size 445/65 R 22.5.
Cab conversion for the concrete pump
To accommodate the K80H concrete pump and comply with the maximum overall height of less than 4 m, the roof of the short Actros S-cab was flattened and the vehicle height lowered to 3,035 mm, similar to what is done on a car transporter. This measure also ensures unhindered use of the boom and provides enough clearance for reliable operation. The headroom remaining in the cab is 1,400 mm, which does not restrict the driver ergonomically. The displays and control elements from the Actros instrument panel were retained and are supplemented by additional symbols for controlling the steering axles.
To create space for installation of the third front axle and provide enough room for the concrete pump, add-on components such as the fuel tank and AdBlue reservoir, battery holder and air reservoir have been moved to the rear. The arrangement of the components was determined in close cooperation with the manufacturer of the concrete pump.
The exceptionally tight turning circle of about 33 m makes this highly maneuverable chassis ideal for use on European construction sites. With its overall length of 14.99 m, it can almost turn around in place. Pumping at extreme heights is thus also possible under limited space conditions, meaning wherever accessibility and operation of the usual standard-sized booms present difficulties.
