Hamm has already been successful with its HD series of articulated tandem rollers for years. Now, the South German company is expanding its range of articulated tandem rollers at the top end. The roller manufacturer has once again realized numerous innovations in its two new 12 tonne and 14 tonne rollers. The radically redesigned tandem rollers with unique visibility features, an extremely user-friendly operating concept and impressive performance data will be presented to the world's trade public for the first time at the Intermat exhibition in 2009. The machines are being launched onto the market with the designation "HD+".

The HD series of Hamm tandem rollers made its market debut almost 10 years ago, heralding a change in the design and construction of modern articulated tandem rollers. The innovative machines stood out visually through their completely new design, allowing many functions to be realized that other tandem rollers simply could not offer at the time: for the first time ever, the driver had a clear view of the drum and could monitor the water sprinkling at any time. The HD series also set new standards in terms of its clear arrangement.

More comfort – more performance – more quality

Hamm has remained true to these principles and once again set new standards in terms of comfort and visibility with its HD+ tandem rollers . "Our aim was to build heavy tandem rolllers with outstanding visibility – and that is precisely what we have done. Despite the machines' size, the driver of these compact rollers always has a perfect view of the drum and his surroundings, as well as a very comfortable workplace. Together with the numerous technical innovations, we can now present a high-performance series offering ideal conditions for high-quality and highly productive compaction," explains Marketing Manager Gottfried Beer in conjunction with the new HD+.

Unique visibility features

The XXL cab provides a comfortable, ergonomically optimized workplace with hitherto unattained freedom of movement. In best Hamm tradition, the driver has a complete overview of the drums and water sprinkling from any seated position. A new adjusting mechanism allows the seat to be moved laterally all the way to the outer edge of the cab and effortlessly rotated. From the cab edge, the driver has an outstanding view of the edge of the drums and the area surrounding the machine. High-intensity lights additionally illuminate the edge of the drums in the dark.

Self-explanatory operation

The newly designed dashboard is securely attached to the steering column. Consequently, it is in the driver's field of view from every seated position without impairing either his view or his freedom of movement. Furthermore, the shape of the steering column makes it very easy for the driver to enter and exit the cab. Operation is self-explanatory. The driver has control of all important operating data of the roller at all times thanks to the clearly arranged operating elements and displays with unequivocal symbols.

Improved handling characteristics

The HD+ series also has some new features to offer in terms of handling: the revised pivot assembly is now located beneath the cab, virtually at the centre of the machine. This results in an extremely favourable load distribution. Consequently, driving stability is greatly improved, as is the quality of the paving. Impressions in the asphalt when compacting in bends or around roundabouts are now a thing of the past thanks to the even load distribution. Instead, surfaces with perfect evenness are quickly produced in just a few passes. The new pivot assembly has another advantage: the offset during crab steering has been almost doubled in comparison with previous rollers in the HD series. This lends the tandem roller excellent manoeuvrability and provides plenty of clearance for processing edges neatly.

Additional comfort is also provided by the steering system, with only a few turns of the steering wheel being necessary to turn the roller. What's more, the driver can set the maximum speed on the display, so that the full deflection of the control lever corresponds exactly to this speed. When reversing, the automatic transmission provides for smooth braking and acceleration, resulting in even asphalt surfaces without bumps or dents.

Hammtronic included

Hamm equips all HD+ rollers with its "Hammtronic " machine control system as standard. This governs the speed of the diesel engine, for instance, to ensure that optimum performance is available at minimum consumption.

Another special feature of the Hamm machines with "plus" factor: the frequency and amplitude of the vibratory drives can be independently adjusted in both drums. This allows the rollers to be precisely matched to the requirements of the asphalt. Hamm also offers an additional high-frequency version for the US market, where paving is carried out at a very high advance speed and compaction has to be correspondingly fast.

3 m machine height simplifies transportation

The overall height of the heavy-duty rollers has been reduced to 3 m. This makes transport just as easy as work under bridges or projections. The new design also reduces the access height by 25 cm, making it easier for the driver to get in and out.

Greater productivity thanks to enlarged water tank

With a capacity of almost 1,200 l, the water tank of the HD+ provides sufficient water for compaction without having to stop to refill the tank. Ingenious details such as the ease with which the water tank can be emptied, the antifreeze injection system and self-cleaning filters also facilitate day-to-day work and maintenance. All these aspects ensure a high level of availability and productivity for the tandem rollers.

Clean engine technology on board

The modern water-cooled 4-cylinder in-line engine with common rail fuel-injection system has an output of 100 kW and naturally fulfils the exhaust emission requirements of EU Stage III and US EPA, Tier III, guaranteeing quiet eco-friendly operation. An intelligently designed air-routing solution additionally keeps the waste heat from the engine away from the driver's cab.

Technical details: HD+ 120, HD+ 140