The new PR 776 is powered by a Liebherr 12-cylinder diesel engine developing 565 kW (768 HP / 759 HP). The PR 776 has a maximum operating weight of 74t and is equipped with blade capacities of 18m³ / 23.5yd³ (semi-U blade) or 22m³ / 28.8yd³ (U blade).
Efficiency and performance: Modern, infinitely variable drive concept
The modern drive concept of the new PR 776 offers extremely efficient and safe operation to customers. A new feature in this machine class is the infinitely variable hydrostatic travel drive, which is used for all crawler tractors from Liebherr
Another advantage of the modern drive concept is the optimization of pressure flow. Hydraulic servo pressure is based on-demand according to the task. If, for example, the full feed of pressure supply is not required when operating, this is automatically returned.
The ECO function is standard for all Liebherr Generation 6 crawler tractors – including the new PR 776. It allows operators to choose between high performance and maximum efficiency. The ECO control system enables greater travel drive efficiency in light to medium operations, and also provides greater fuel savings.
The proactive power control is another innovation of the 6th generation crawler tractors. Internal engine and external machine parameters are recorded, such as the current deflection of the joystick. If required, the engine power is automatically increased for a brief period based on the current requirement. As well as responding more rapidly, the machines offer a significant increase in performance potential and pulling power and a higher reverse speed.
Liebherr custom-engineers integral equipment solutions. The intelligent Liebherr engine management system combined with the Liebherr Power Efficiency System and the hydrostatic driveline allows Liebherr to master and optimize all equipment systems and processes to maintain constant engine speed, increase overall machine efficiency and reduce fuel consumption of the PR776. Differentiating Liebherr’s travel drive concept from other drive concepts available on the market, with which the engine speed fluctuates sharply during operation.
All of these measures lead to significantly lower fuel consumption than the industry standard with similar pushing performance.
Another key advantage of hydrostatically powered crawlers when working in restricted spaces is the excellent manoeuvrability with continuous power to both tracks.
With an optional GPS navigation system, the work progress and the surrounding area can be visualized. increasing machine productivity and minimizing operator stress and strain.
Pendulum-mounted guide wheels and track rollers ensure excellent chain traction and significantly reduce equipment vibration.
Operator comfort: Intuitive operation
The operator quickly finds his bearings in the new PR776 platform developed especially for this machine class. A focal point for development was the simple and safe operation of the crawler tractor. The multifunction joystick houses all operating and steering movements at the palm of the operator’ hand with only one electronic input element. This intuitive operating concept was subject to rigorous testing at Liebherr and is an important innovation for the 70 t crawler tractor’s category, particularly in mining applications.
The modern and spacious workstation in the PR 776 ensures excellent environment for greater performance and relaxed working conditions. The cab is purposely designed. All instruments and operating controls are carefully organized for easy reach. All key functions and machine settings can be adjusted by the operator via the touchscreen display. ECO function parameters, automatic engine speed reduction, travel drive response, steering as well as standard safety functions such as the rear view camera can be all be accessed through the intuitive touchscreen display.
Operators can conveniently adjust multiple machine settings including travel drive, blade and rear ripper to their needs. Ergonomically shaped joysticks ensure operator’s comfort. An automatic air-sprung seat detects and adjusts to the operator and deactivates the machine when exiting the cab without a safety lever having to be actuated.