The challenge: making complexity manageable
As performance increases, so does the complexity of operation. On an inner-city construction site, for example, the crane operator must be able to quickly identify functions and operate them safely – even under time pressure. The steplessly height-adjustable operator’s cab ensures optimum visibility.
Equally crucial, however, is the design of the control system. The more clearly the controls are laid out, the lower the risk of errors, particularly during long shifts. At the same time, demands on technical integration are increasing. Modern machines incorporate more and more functions. However, every additional function also increases complexity.
Initial project requirements
At the start of the project with Schlegel, the focus was on integrating classic cab functions. These included cab lighting and generator control via the battery. As development progressed, further requirements were added. For example, the three windscreen wipers and the windscreen washer function were also to be controlled via the control panel. Furthermore, the intermittent wiper control and rain sensor integration were developed in close consultation with the customer and incorporated into the control panel. The system was supplemented by an integrated 20-watt audio amplifier unit to handle communication between the cab microphone and the external loudspeaker.
Another design challenge was that the control unit had to be integrated into the crane cab in the immediate vicinity of the armrest, i.e. in a confined space. A compact yet functionally comprehensive solution was therefore crucial.
Consolidated functions on a central circuit board
Schlegel developed a control panel tailored specifically to the spatial conditions. This reduces the amount of wiring required and keeps the system architecture clear and straightforward. Connection is done via a multi-pin connector, which simplifies installation and servicing. “A reliable, collaborative relationship and direct on-site support enabled us to find fast, practical solutions,” says the Liebherr development team. Schlegel’s involvement from the prototype phase was a decisive factor. This allowed structural, electronic and practical requirements to be coordinated in parallel.
Designed for everyday use on construction sites
In addition to the system architecture, the focus was on practical suitability. Construction sites are characterised by vibration, temperature fluctuations and constant mechanical stress. The control unit is therefore robustly constructed and designed for high operational reliability. “Robustness, reliability and quality are our top priorities. The Schlegel control panel meets these requirements,” concludes the team in Biberach.
Partnership as a development approach
For over 80 years, Schlegel has been developing and manufacturing control elements and system solutions for industrial applications at its Dürmentingen site, ranging from classic pushbuttons to complex bus systems. However, in the project with Liebherr, the focus was on system integration rather than the individual product. The result is a scalable platform for future requirements, combining an ergonomic operating concept with reduced hardware complexity and bus-compatible architecture.
Conclusion
With the Schlegel control panel, Liebherr is focusing consistently on integrated system architecture in the MK series. The result is not only a well-structured user interface, but also an expandable, maintenance-friendly solution that meets the growing demands of modern mobile construction cranes. This is particularly important in inner-city environments, where precision, clarity and efficiency are paramount.
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