Design Challenge - June 2013

Alberto Seco - Flexible Frame Linkage

Lumede/Oliver Becker DesignThe vertical articulation of the frame which provides steering, the longitudinal turning of both front and rear frames and the suspension system are the main characteristics that define articulated dump trucks as units specially indicated to work on soft or uneven terrain. So Articulated haulers can operate where Rigid dump trucks cannot operate.
For two decades the 40tonne ADT has been the flagship on most OEMs range, but bigger models coming from South Africa, Norway, USA or China are clearly setting a trend towards larger units.
Suspension system on current ADTs entirely relies on axles while the double articulation system offers uncushioned steering and rotation of both front and rear frames. It provides superior gradeability compared to rigid dump trucks but can also lead to accidents.
A common accident consists of rolling over the bed while the front frame which holds the front axle, engine and operator station remains horizontal (see case A). It usually happens rearwards when climbing up a rock pile for dumping the load or loaded frontwards on very uneven ground. Depending on the Turning ring (rotating hitch) height / truck width ratio the front frame can also roll over. The wider the ADT is, the smaller is this ratio, leading to a bigger possibility of causing a serious accident with rolled over cab.

Outstanding stability would not just be provided by the very low centre of gravity, as the independent wheel position system would turn the roller into a full hillside machine when working on slopes. The suspended wheels would offer a more cushioned movement on uneven ground. The design of the bi-material tyres is intended to replicate the drum effect and to improve side grip while compacting on slopes.

Integration of the steering wheel and seat would enable the 360º rotation of the cockpit so the operator could choose the best view for working. For instance, in order to achieve the best compaction outputs, a second pass can be easily carried out by rotating the operator station by 180º. The rotating cockpit would be especially useful on narrow paths or areas, as there would be no need for steering the roller.

The cab is based on a three-double-post structure; this design splits every post into two pillars and creates profiles so slim as to be almost invisible. Visibility is also boosted by 7.5m2 of glass and a complete set of working lights for night operation. Permanent LEDs are included as a day safety feature. The shape of the bonnet is also designed to improve visibility from the 180º positions of the operator station.

The cab is accessible from both sides by means of two sets of steps that can be rotated in order to fill the fuel tank or reach other components. The AdBlue tank, located at the rear of the cab, can be easily reached from the cab access platform. Engine parts and batteries are easily and safely accessible from the counterweight by means of electrohydraulic engine bonnet tilt.

The design language for this concept is based on a rectangle with two round sides, which can be seen right from the structural components through to the styled ones.


The bonnet has been designed to accommodate the biggest package to comply with the US Tier 4 Final/ EU Stage IV legislation which start to come into force next year:  a 500hp, 16 litre, 6-cylinder engine with exhaust gas recirculation (EGR), diesel oxygenated catalyst (DOC), diesel particulate filter (DPF) and selective catalytic reduction (SCR). This bonnet could also be a home for a future LNG drive system.

Parallel lines have been used as a reminder of the vertical movement experience provided by the new suspension system. The characteristically trapezoidal shape of the body has been extensively used on bonnet and cab shapes in order to visually link both the front and the rear frames.

The access to the cab platform has been designed from the steps located on the front frame by the bonnet, with convenient handrails and away from the potentially hazardous articulation and body areas. The cab is provided with two doors, a left hand side and a right hand rear so that operators can enter the machine easily and safely from both sides of the truck platform.

Cab A-pillars have been aligned to the bonnet and access steps in order to improve front and side visibility. The trapezoidal section of the cab would offer maximum rearwards visibility, on the articulation area.

Maintenance has been minimized on the articulation area and it has been focused on the bonnet platform which can be accessed from the steps or cab platform after tilting up the upper bonnet. The side covers of the bonnet remain as a safety barrier. Grouped engine oil filters and systems, service and grease points are easily accessed via this platform.

The front bumper has the ability of swinging-down in order to provide a service platform with anti-slip steps for the cleaning of the cooling package after the front grille swings up.

Refueling can be carried out from ground level or on the top of the swing-down front bumper as two flaps are located on both sides of the bonnet front giving access to the fuel and the AdBlue tanks.

Finally “50+” does not only stands for 50 tonne capacity, but for a tribute to the ADT that will celebrate its 50th anniversary in 2016.

More images from Alberto Seco

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Alberto has been involved in design projects from mobile phones to heavy equipment. After a spell at an Italian design consultancy and as an industrial designer, he now works in the auto sector





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