MINExpo 2016: Liebherr presents hydrostatically-powered crawler tractor
Published by Jonathan Rowland,
Liebherr presented its first crawler tractor in the 70 t category to the North American market at MINExpo 2016 in Las Vegas. The PR 776 is designed for mining and quarrying operations.
Powered by a Liebherr 12-cylinder diesel engine developing up to 565 kW, the new PR 776 has a maximum operating weight of 74 t and is equipped with blade capacities of 18.5 m3 (semi-U blade) or 22 m3 (U blade).
Efficiency and performance
The PR 776 also includes a modern drive concept – the infinitely variable hydrostatic travel drive – that offers efficient and safe operation to customers. Along with Liebherr’s engine management system, the travel drive concept keeps engine speed constant, increasing machine efficiency and reducing fuel consumption.
Another key advantage of hydrostatically-powered crawler tractors when working in restricted spaces is the excellent manoeuvrability with continuous power to both tracks.
The PR 776 also comes with ECO function, allowing operators to choose between high performance and maximum efficiency. A standard in Liebherr Generation 7 crawler tractors, ECO mode enables greater travel drive efficiency in light to medium operations – another feature that provides greater fuel savings.
With an optional GPS machine control system, the work progress and the surrounding area can be visualised. This, in turn, increases machine productivity and minimises operator stress and strain. Pendulum-mounted guide wheels and track rollers ensure excellent chain traction and significantly reduce equipment vibration.
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’s hand with only one electronic input element. This intuitive operating concept was subject to rigorous testing at Liebherr and is an important innovation of the 70 t crawler tractor category, particularly in mining applications.
The modern and spacious workstation in the PR 776 provides an excellent environment for greater performance and relaxed working conditions. All instruments and operating controls are carefully organised for easy reach; all key functions and machine settings can be adjusted by the operator via touchscreen display.
ECO function parameters, automatic engine speed reduction, travel drive response, and steering, as well as standard safety functions, such as the rear view camera, can be also 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 comfort. An automatic air-sprung seat detects and adjusts to the operator’s shape and deactivates the machine when exiting the cab without a safety lever having to be actuated.
The design of the PR 776 offers all-round visibility for safe and efficient day-to-day operation. Safety is enhanced by the excellent visibility of the worksite, the blade and rear ripper, which is assured by the larger panoramic windows and downward slopes of the PR 776. A new feature in this class is the Roll Over Protective Structure (ROPS) / Falling Object Protection Structure (FOPS), which is integrated directly into the cab structure as standard for Liebherr crawler tractors.
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.
Another safety factor is the newly developed illuminated safety steps. Depending on the chosen equipment level, high performance LEDs are used for ideal illumination of the work area. The modular lighting concept is one feature of the new machine design and makes it possible for the lighting to be adapted optimally to the respective use.
Optimal service accessibility and long change intervals Centrally located maintenance points, access flaps and engine compartment doors that open to a wide angle, a tilting cab as standard equipment and, as an option, a radiator fan that can be swung out for cleaning – all of these are features that speed up and simplify servicing work on the new Liebherr crawler tractor.
The new PR 776 also has long change intervals for operating fluids, such as hydraulic or engine oil. Depending on the nature of the work, and provided that regular checks are performed, the change interval for Liebherr-plus oils can be as long as 8000 hrs of operation.
The standard Liebherr fleet management system LiDAT provides an accurate and efficient overview of essential servicing work, warning messages, the machine’s position and actual consumption data and filling levels. Depending on the agreement with the customer, the data is updated several times a day and can be called up whenever needed via the internet.
Read the article online at: https://www.worldcoal.com/product-news/14102016/minexpo-2016-liebherr-presents-hydrostatically-powered-crawler-tractor/
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