GRW 280i: New Easy Drive operating concept and sophisticated driving dynamics

The Easy Drive operating concept is now also available for pneumatic tyre rollers

With the invention of the asymmetric frame and the changeover to a modern driver's cab, HAMM introduced a radically different approach to the pneumatic tyre roller concept some years ago. Now the Tirschenreuth-based specialists have completed the next evolutionary advance: With the introduction of the Easy Drive operating concept to the pneumatic tyre roller segment, the GRW 280i heralds a new era. HAMM's award-winning operating concept makes for intuitive operation and stands out for its exceptionally ergonomic driver's platforms. "It simplifies the operation of complex rollers and enables us to avoid the need for complicated, menu-guided controls," explains Gottfried Beer, Head of Marketing at HAMM. The totally language-neutral operation of the Easy Drive roller is very simple and easy to master, because the small number of switches are intelligently arranged in the uncluttered driver's platform. All Easy Drive rollers have a steering wheel. Drive control is by means of a joystick with clearly visible push-button switches in an ergonomically ideal layout on the multifunction armrest. Because HAMM has adopted a cross-series approach in the development of the concept, the operating elements for identical functions are now always in the same position on the driver's platform for all Easy Drive rollers – that is to say on tandem rollers, compactors and pneumatic tyre rollers alike. This leads to an increase in efficiency, because, in future, operators will be able to switch between different HAMM rollers flexibly and without a period of familiarisation.

The GRW 280i ballasting concept

HAMM has also further increased the flexibility of the GRW 280i in terms of machine weight: Thanks to a modification to the ballast space between the wheelsets and the open-bottomed compartmented frame with inserts, ballasting the roller is now even easier. Prefabricated steel, magnetite or concrete ballast bodies can be inserted or removed using a forklift truck, for example. HAMM offers custom-designed ballast body kits for this purpose. In addition, each customer has the facility to fit the roller with his own ballast bodies. This enables great flexibility in terms of machine weight adjustment. Thanks to the ingenious arrangement of the ballast space, the load is always evenly distributed over both axles – the perfect prerequisite for top-quality compaction.

Sophisticated driving characteristics for optimum compaction

A hydrostatic rear-axle drive on the GRW 280i enables a good travel speed – both when being moved as well as during compaction. The driver is able to set the desired speed for any working situation by means of a sensitive electronic control. In addition, a pre-selection wheel on the control panel allows easy setting of the prescribed working speed. Furthermore, the intelligent drive control provides the basis for top-class compaction results: Automatic soft ramps enable gentle, even braking and acceleration. This driving characteristic guards against uneven compaction. To match the high top speed of the GRW 280i, a newly designed front steering axle with disc brakes provides the braking power needed and ensures a high level of safety when travelling fast, even when carrying the maximum ballast load. The optional anti-slip control ensures optimum traction when working on uneven ground as well as on surfaces with varying temperatures.

Ingenious wheel suspension for homogenous weight distribution

HAMM has also come up with an innovative solution for the wheel suspension: Two swingarms positioned between the GRW 280i's front wheel pairs distribute the load evenly on the wheels, irrespective of the ground characteristics. Irregular compaction is thus avoided thanks to the even surface pressure. Another benefit: The mounting bracket is designed so as not to intrude into the driver's field of vision and impair the view of the construction site.

Unobstructed view of the construction site

The asymmetric frame – one of the special features of the HAMM GRW pneumatic tyre roller – follows the track offset between the front and rear wheelsets. It is both a hallmark and a quality benefit, because the design in symmetry with the wheelsets provides a clear view of the outer wheel edges. Also included as an option in the HAMM programme is tyre lighting for the best possible view of the tyres when working at night. In addition, the compact shape of the GRW 280i, the design of its engine hood and fuel tank, the high seating position, the sliding and swivelling seat plus the spacious panoramic cab provide the driver with a working environment that presents an unobstructed view in all directions. This means that persons and objects are seen in good time and of course that HAMM satisfies the latest stringent requirements with regard to field of vision.

The tyre-inflation system enables precision adjustment of contact pressure

The wheel load of the GRW 280i varies between 1.25 and 3.5 tonnes per wheel, depending on the ballasting load. Adjusting the tyre pressure allows the contact pressure and tyre footprint to be changed to the optimum values for the compaction task in hand. A push button on the dashboard allows the filling pressure to be changed with uniform effect on all tyres of both axles.

Practical solutions for water sprinkling

The water sprinkling system with spray nozzles directly above the centre of the tyres is conveniently operated via the multifunction armrest. A large water tank is fitted to the GRW 280i as a standard feature; HAMM can supplement this with an optional additive tank. The additives are automatically dosed and mixed according to the requirements. This eliminates both the need for manual premixing and the risk of separation. The operator is able to vary the quantity of water or release agent during compaction.

Perfect maintenance – with safety assured

HAMM has developed an intelligent solution for the steps to the maintenance platform for the purpose of safely carrying out maintenance work: These are integrated into the outer contour and simply opened outwards. Because they stick out in this position, the operator cannot forget to retract the steps on conclusion of the maintenance work. The placement of all checkpoints on the right-hand side of the engine simplifies daily maintenance and increases efficiency. The maintenance railing next to the engine hood provides a firm support and ensures safety.

The new GRW 280i pneumatic tyre roller is being launched with a range of basic weights (10 t, 12 t, 16 t, 18 t, 20 t, 24 t, 28 t). The machines are able to carry different quantities of ballast, depending on the basic weight.