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

Hamm has been producing pneumatic tire rollers with great success for over 50 years. Having revolutionized this machine type with its asymmetrical frame design around 8 years ago, the roller manufacturer HAMM is now set to present the next innovation in the pneumatic tire roller market segment in spring 2018 with the GRW 280i. This roller with a Tier 4 engine is the first pneumatic tire roller to feature Easy Drive, the innovative operating concept from HAMM. It also stands out for the additional enhancements made to the advance drive and for the exceptionally flexible ballasting – both of which contribute to the first-rate compaction quality. Added to these are maximum possible driving comfort, exceptionally good visibility and the highest possible operational safety.

The Easy Drive operating concept is now also available for pneumatic tire 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 tire 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 tire 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 operator 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 operator 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 operator platform for all Easy Drive rollers – that is to say on tandem rollers, compactors and pneumatic tire rollers alike. This leads to an increase in efficiency, because, in the future, operators will be able to switch between different HAMM rollers flexibly and without a period of familiarization.

Easy Drive operating concept

The driver's seat, steering column, dashboard, joystick and multifunction armrest form a harmonious unit that enables relaxed and concentrated working.

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 traveling 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.

Flexible ballasting

Additional weights of up to 17 metric tons can be inserted and combined in the ballast space of the HAMM GRW 280i – even on the construction site. The ballast bodies can be filled with various materials, allowing the overall weight to be finely tuned to the specific requirements.

Ingenious wheel suspension for homogeneous 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, therefore, 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 – 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 program is tire lighting for the best possible view of the tires 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 swiveling 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.

Excellent visibility conditions

The asymmetric frame of the HP series is a brand hallmark and a qualitative advantage rolled into one. It always allows you a clear view of the outer edges of the front and rear wheels.

The tire inflation system enables precise adjustment of contact pressure

The wheel load of the GRW 280i varies between 1.25 and 3.5 metric tons per wheel, depending on the ballast load. Adjusting the tire pressure allows the contact pressure and tire 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 tires of both axles.

Practical solutions for water sprinkling

The water sprinkling system with spray nozzles directly above the center of the tires 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 demixing. 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 outward. 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.

Safe and efficient service

When it comes to maintenance, the developers have also attached importance to efficiency and safety. For example, all daily maintenance items are situated on the right-hand side of the engine

The new GRW 280i pneumatic tire 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.