The PR 776 is powered by a Liebherr 12-cylinder diesel engine developing 565kW (768HP/759HP), has a maximum operating weight of 74t, and is equipped with blade capacities of 18m3 (semi-U blade) or 22m3 (U blade).
The modern drive concept of the PR 776 offers efficient and safe operation to customers, Liebherr said. 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 drive concept is the optimisation 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. According to the manufacturer, 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 sixth-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. Liebherr stated that, as well as responding more rapidly, the machines offer an increase in performance potential and pulling power and a higher reverse speed.
Liebherr also added that it custom-engineers integral equipment solutions. The Liebherr engine management system combined with the Liebherr Power Efficiency System and the hydrostatic driveline allows it to optimise all equipment systems and processes to maintain constant engine speed, increase overall machine efficiency and reduce fuel consumption of the PR 776.
A focal point for developing the new PR 776 platform was the simple and safe operation of the crawler tractor. The multifunction joystick houses all operating and steering movements, with only one electronic input element. This operating concept was subject to rigorous testing at Liebherr and is an important innovation for the 70t crawler tractor’s category, particularly in mining applications, the company said.