Liebherr has launched a significant upgrade to its award-winning VarioBase system, dubbed "VarioBase Plus," available on the new LTM 1120-4.1 mobile crane. The core engineering challenge for mobile cranes has always been stability on uneven ground. Traditional cranes rely on a fixed load chart based on the outriggers being fully extended. However, on congested urban sites, full extension is often impossible, forcing operators to use complex, reduced-capacity tables that are prone to human error.
VarioBase Plus integrates high-precision pressure sensors directly into the hydraulic cylinders of the four outriggers (jack cylinders). The system calculates the machine's center of gravity (CoG) in real-time based on the actual support forces measured by these sensors. Unlike previous systems that relied on fixed geometric limits, VarioBase Plus dynamically adjusts the safe working envelope. If the system detects that one outrigger is carrying less load than expected-indicating potential ground settlement or soft soil-it instantly recalculates the crane's stability limits.
A key engineering innovation is the "Smart Envelope Control." The crane's onboard computer creates a 3D model of the working area. If the operator attempts to lift a load that would exceed the calculated stability limit based on the current outrigger pressure, the system does not simply cut off the function. Instead, it automatically reduces the hoisting speed and limits the slewing angle, gently guiding the operator away from the danger zone. This "soft landing" approach prevents sudden load swings. Additionally, the system is linked to the telescopic boom: the boom extension is automatically limited to the maximum safe length for the specific outrigger configuration, ensuring that the crane can safely operate with outriggers extended at 0%, 50%, or 100% without the operator needing to manually consult paper tables. This technology increases the crane's effective lifting capacity by up to 30% in asymmetric configurations compared to standard safety margins.
