Liebherr PR 776: world's first hydrostatically powered crawler tractor in the 70 tonnes category
Liebherr has unveiled its first crawler tractor in the 70 tonnes category – the new PR 776. This crawler tractor is designed for tough mining and quarry operations.
The PR 776 is powered by a Liebherr 12-cylinder diesel engine with 565 kW (759 hp). The PR 776 has a maximum operating weight of 74 t and is equipped with blade capacities of 18 m³ / 23.5 yd3 (semi-U blade) or 22 m³ / 28.8 yd3 (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. This differentiates 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 with similar pushing performance.
Another key advantage of hydrostatically powered crawlers when working in restricted spaces is the excellent maneuvrability 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.
Maximum safety with excellent view of equipment and surrounding area
Safety is enhanced by the excellent visibility of the worksite, and to the blade and rear ripper, which is assured by the large panoramic windows and downward slopes on the PR 776.
A new feature in this class is the ROPS / FOPS protection integrated directly in the cab structure.
Forward visibility is completely unobstructed as the exhaust system and lifting rams have been positioned behind the A-pillars. Also the side view of the working area is clear and unobstructed by the extended work platform. This allows access to the cab, service points and filler necks for auxiliary and operating fluids.