Innovative hydraulics for highly specialised construction machinery by Linde Hydraulics

Menzi Muck uses Linde Hydraulics LSC system in its new walking excavator series

The new walking excavator series from Menzi Muck offers drivers additional functions – thanks to the LSC system from Linde Hydraulics.
Photo by Linde Hydraulics GmbH & Co. KG

The Swiss excavator manufacturer Menzi Muck has introduced the first model in its new walking excavator series at the bauma trade fair. The operating hydraulics in these particularly specialised construction machines are designed as a complete unit of Linde Hydraulics components, including the electronic control unit.

Walking excavators – also referred to as spider excavators– are exceptionally specific construction machines that move forwards on four wheels, which are hooked up to the undercarriage by legs. These legs can also be used to align the track width and the height of the vehicle over a wide variety of levels, ensuring that the machines remain highly flexible and can be adapted to the environing conditions, both in drive mode and work mode, when the stabilisers on the legs are extended. This means that they are ideally matched to working in places such as very steep slopes or in streams.

The hydraulic control functions are combined in a compact LSC monoblock.
Photo by Linde Hydraulics GmbH & Co. KG

Very dynamic, superimposed movements
An appearance on German TV program “Wetten, dass.?” in 2006 demonstrated how flexible these machines can be. The remarkable video is still available on YouTube and shows a walking excavator from Swiss manufacturer Menzi Muck climbing over a five-metre-high concrete block – using the bucket as additional support – and proving just how appropriate the name “spider excavator” is.

Capitalizing on this great degree of freedom not only requires a very experienced operator, but also a powerful hydraulic system that can execute the often superimposed movements with the necessary dynamics or sensitivity.

Joint innovation at a high level
During development of its new series, which Menzi Muck introduced to the public at bauma 2013, the excavator manufacturer worked in close cooperation with Linde Hydraulics and Girtec AG, the Linde Hydraulics system partner based in Switzerland. Together, the companies developed a hydraulic system that utilizes the features of the Linde Synchron Control (LSC) and not only meets the demanding requirements of the highly specialised movements of a walking excavator, but also enables additional functions to be implemented.

A tandem pump unit, consisting of a variable displacement pump and a regulating pump, supplies the working hydraulics and traction hydraulics
Photo by Linde Hydraulics GmbH & Co. KG

Supply via tandem pump unit
At the core of the hydraulic system is a tandem pump unit. A load-sensing regulating pump of type HPR 105-02 E1L for the open circuit supplies the working hydraulics with hydraulic liquid, while an HPV 75-02 E2 variable displacement pump for the closed circuit drives the traction motors.

The hydraulic control functions are combined in a compact LSC monoblock.
The unit is controlled via a compact LSC monoblock, in which three directional control valves are integrated in a single cast housing. The pressure relief function is also integrated in the monoblock, and special functions can be implemented using an intermediate plate. The valves have a flow-optimised design and feature integrated pressure compensators and pressure copiers.

Social load sensing
The special features of the LSC system include its “social load sensing” capability. This is a special kind of volume flow regulation for superimposed movements, which are frequently required for walking excavators.

Complete system with electronic control unit and joystick
The electronic control unit for the walking excavator’s hydraulics also comes from the Linde Hydraulics modular system. It maps the complete traction hydraulics and working hydraulics of the new machine.

Menzi Muck walking excavator at work.
Photo by Linde Hydraulics GmbH & Co. KG

Compact and powerful hydraulic system from a single source.
Menzi Muck has already had positive experiences with hydraulic components and systems from Linde Hydraulics. When developing the new series, called the M 3/M 5, it was not only the reliability and flexibility of the LSC system that was of crucial importance, but also the high power density of the central components: The combination of an HPR and HPV pump is much more compact and powerful than competitors’ systems.

For further information please visit:  www.linde-hydraulics.com

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