LIEBHERR says it has achieved new levels of performance, economy, operator convenience and reliability with its line of Generation 6 crawler excavators.
The new series of machines was on display at Intermat 2009 and is said to have set new standards for crawler excavators in the 21 to 28t category.
There are three new-generation crawler excavator models in the range, the R 906 with a service weight of 21.7 to 23.3t, the R 916 Litronic with a service weight of 23.7 to 26.4t and the R 926 Litronic, service weight 25.7 to 27.1t.
Each of the three new crawler excavators is powered by a Liebherr four-cylinder construction-machinery diesel engine. Outputs are 105 kW for the R 906 Litronic, 115 kW for the R 916 Litronic and 130 kW for the R 926 Litronic. Liebherr says the engines comply with internationally valid exhaust emission limits (stage IIIA/tier 3).
Engine management with CAN bus system integration is said to keep engine speeds more constant and thus optimises fuel consumption and makes more efficient use of the available power.
Each of the three new crawler excavator models is available in either a ‘Classic’ or an ‘Advanced’ version. The ‘Classic’ Generation 6 versions are intended for typical earthmoving tasks; the ‘Advanced’ versions are equipped with an even higher level of innovative Liebherr technologies and are thus high-performance ‘full option’ products, suitable for all kinds of tasks. In addition to earthmoving, the machines are said to offer customers valuable benefits in mining, embankment construction, industrial applications or on demolition sites.
All Generation 6 crawler excavators are equipped with the ‘Positive Control’ hydraulic system, and the corresponding control-system logic.
Two independent hydraulic circuits make it possible to energise components in the most efficient manner. In particular when movements have to be superimposed, the necessary volumetric flow can be made available quickly enough, with optimal use of the available energy. Maximum individual movement speeds are obtained by adding the pump circuits together.
The Liebherr “Positive Control” hydraulic system thus enhances performance when excavator movements have to be superimposed, for instance when grading and during travel either straight ahead or in a curve. The Advanced version’s higher operating pressure also increases tractive effort as well as tearout and breakout power.