Liebherr showcases the PR 726 Litronic crawler tractor at Steinexpo 2017

The PR 726 Litronic has an operating weight between 16,000 kg and 19,800 kg and its Liebherr diesel engine delivers an output of 120 kW / 163 hp. The Liebherr PR 726 is powered by a 4-cylinder Liebherr diesel engine that complies with the Stage IV / Tier 4f emissions standard. In order to achieve the stipulated emissions and consumption goals, the entire combustion process has been optimized to reduce the particles, even within the engine, to a minimum.

Liebherr also relies on selective catalytic reduction (SCR technology) for the PR 726 to simplify the system and to optimize the exhaust gas aftertreatment. This makes the use of a diesel particulate filter superfluous, thus simplifying maintenance for the customer. The highly efficient combustion process facilitates low fuel consumption.

The optimal adaptation of the engine parameters to varying operating conditions is supported in a number of ways by, for example, an in-house developed common rail injection system incorporating an in-house developed electronic engine control.

The main components of the generation 6 crawler tractors come from Liebherr's own production line and are therefore optimally tailored to the machine. Among these components are the diesel engine and the common rail injection system, as well as electronic and various hydraulic components. Here, Liebherr can draw on over 50 years of experience in the development of crawler tractors.

Maximum performance and efficiency

As with all generation 6 crawler tractors, the new PR 726 Litronic also features an electronic drive control with integrated ECO function. This allows the operator to select between high performance and maximum economy. The ECO control system here enables even greater travel drive efficiency in light to medium-duty operations.

The proactive power control is another 6th generation innovation. This involves the detection of various machine parameters and if required results in an automatic increase of the engine output for a short time. As well as responding more rapidly, the machines offer a tangible increase in pushing performance and dynamic response.

The hydrostatic drive keeps the engine speed at a constant level. All drive components and the intelligent Liebherr engine management are optimally adapted to the speed, which makes a significant contribution to reduced fuel consumption.

The combined inching brake pedal facilitates the transition from conventionally driven machines to Liebherr generation 6 crawler tractors. With this equipment option, both the travel speed and the brake can be controlled via the foot pedal. A key enhancement is the 3-way joystick (which can be locked in forward, stop, and reverse), which is also available as an option.

The PR 726 offers exceptional smooth running and perfect crawling properties. Long running gear systems, an effective balance, and optimal visibility are superb prerequisites for precise leveling, irrespective of whether this is done manually or using automatic grading systems.

Plug-and-play: Easy installation of machine control systems

For simple and trouble-free implementation of automatic machine control systems, Liebherr also offers factory-fitted preparation kits for the generation 6 crawler tractors, which are available for the systems of well-known manufacturers such as Trimble, Topcon, or Leica, for example.

Whether the machine operator opts for a 2D or 3D control system for the intended deployment, both laser and GPS systems or control systems with total station can be used on the same machine without any problems. This makes the installation easier and offers the owner the highest level of flexibility in the selection of their system.

If required by the project conditions, an individual machine control system can also be used consecutively on different Liebherr crawler tractors that are factory prepared resulting in considerably lower investment costs for the operator.

Liebherr works intensively with the manufacturers of the control systems both in the area of development and after-sales, thereby ensuring that the user always receives optimal service from their chosen supplier.

Equipment for any application

The new PR 726 Litronic is made complete through its comprehensive range of equipment. This starts at the front with a universal 6-way blade, with folding corners as an option for easy transport, extending through to a straight blade and semi-U blade for moving larger quantities of material. To further simplify machine transportation, a semi-U blade with an overall width of 3 meters for a track width of up to 610 mm is also available. At the rear, 3-shank and 5-shank rippers can be chosen as well as, for example, a hydraulic rope winch, counterweight or drawbar.

Based on the extensive experience of material handling operations that Liebherr has gained with its large dozers, the new PR 726 Litronic can also be configured for industrial applications such as handling of coal or wood chippings.

The new PR 726 will also be offered in a special dozer version for landfill sites, adding to the extensive range of Liebherr machines for this target group. Special equipment features make this model the ideal system solution for this challenging field of application and include, for example, a pressurized operator's cab as standard, special seals in the cab and engine area, protective devices and covers, optional reversible fans and special landfill blades with trash tracks or striker bars.

Modern design and comfortable new cab

The modern design of the new generation 6 crawler tractors, with sloping edges on all sides and panoramic windows, offers the operator an optimum all-round view of the terrain as well as the blade and rear ripper. The view over the engine hood is completely clear as the exhaust stack and lifting cylinders have been positioned behind the A-posts. Good visibility enhances efficiency and improves safety in day-to-day work.

Numerous innovations in the operator's cab of the larger generation 6 machines have now filtered down into the compact class. The travel and operation joysticks make ergonomically safe handling and even more convenient work possible thanks to the new T-shape. The required traveling speed range can be preselected directly on the joystick enabling control of the tractor to be selected precisely, especially at low speed. Driver detection takes place automatically by means of the integrated seat contact switch without a safety lever having to be activated.

The touch-sensitive system display for Liebherr earthmoving machines is also featured on the new PR 726 Litronic. This enables important operating parameters, such as the ECO function or the travel drive response and steering, to be adjusted intuitively and with a clear overview.

For optimum illumination of the working area, halogen headlights or high-performance LEDs are used depending on the chosen equipment level.

Simple maintenance, low operating costs, optimal planning reliability

Centralized servicing points, wide opening access flaps and engine compartment doors, an operator's cab that tilts as standard and fans that fold out for cleaning (optional) facilitate perfect service access and simplify the maintenance process.

Depending on the application, and provided that regular quality checks are performed, the hydraulic oil change interval can be as long as 8,000 hours of operation. Compared with the predecessor model, the maintenance intervals of the diesel engine in the PR 726 have been doubled to 2,000 operating hours, which results in reduced operating costs overall.

The PR 726 Litronic’s undercarriage is a completely new development. The segmented sprocket has a larger diameter with more teeth so that the operating life of the bushings and sprockets is extended. The Liebherr FTB undercarriage is also available as an option for the PR 726. This swivel undercarriage with rotating bushings, exclusively developed for Liebherr, is particularly well-suited for work on soft, abrasive ground and considerably extends the service life in sand, for example. If used in areas with impact loads, such as on stones and rocks, the trusted tracks with lifetime lubrication are the ideal solution. Both undercarriage versions can be retrofitted retroactively.

As with all previous generation 6 models, the PR 726 features a 3 year / 5,000 hr warranty on the whole drivetrain as standard and without charge. In addition, Liebherr offers special guarantees as well as customized inspection and service programs. This enables maintenance checks to be optimally scheduled giving customers reassurance across the whole service life of the machine.

Information about all machine data anywhere, at any time

LiDAT, the data transfer and positioning system from Liebherr, supplies information, for example, on the machine location and operation of the machines. Examples of this include the position of the machines, operating and utilization times, fuel consumption and also service interval information. LiDAT data can also be used as a basis for the calculation of rental rates.

The precise location of the machine fleet at all times gives the fleet operator more planning reliability. Technicians can be sent out and spare parts planned more optimally thanks to the direct access to each machine. Such a significant cost saving can be achieved while, at the same time, improving machine availability.

The LiDAT data can be accessed via GPRS or data carrier. As just a web browser is required to use LiDAT, information can be made readily available on a variety of end-user devices. With user definable machine groups, large construction sites can be delimited for purposes of organization.

Additional security is offered by an automatic alarm function, which can be set up for particularly important information, for example. notification of critical operating conditions or a machine leaving a predetermined zone or being operated outside authorized hours.