Liebherr MK 73-3.1 Load Chart PDF + Specifications

The Liebherr MK 73-3.1 mobile construction crane represents a versatile solution within the MK series, developed to address the increasing demand for compact, fast-erecting cranes capable of operating efficiently in urban and space-restricted jobsites. The crane integrates the advantages of a traditional tower crane with the mobility of a truck-mounted unit, allowing it to travel quickly between sites and be ready for operation in approximately 10 minutes without the need for additional transport vehicles. The MK 73-3.1E variant builds upon this concept by incorporating an electrically driven superstructure with a hybrid power supply, enabling operation via external site power or an onboard generator, significantly reducing noise and local emissions.

Mounted on a 3-axle carrier with a 6 x 4 x 6 drive and steering configuration, the crane offers excellent maneuverability, supported by multiple steering modes that achieve a tight turning radius of approximately 9.67 meters. The carrier is powered by a 6-cylinder diesel engine from Cummins, delivering 243 kW and allowing a maximum travel speed of 80 km/h, ensuring efficient relocation between job sites. Liebherr’s single-engine concept is applied, enabling both travel and crane functions to be powered through one engine, while ECOmode optimizes fuel consumption and operational efficiency.

The crane provides a maximum lifting capacity of 6,000 kg and can lift 2,000 kg at its maximum radius of 38.5 meters. With a maximum hook height of 51 meters, it is well suited for mid-rise construction projects. The luffing jib can be positioned at 0°, 15°, 30°, and 45°, offering flexibility when working around obstacles or in densely built environments. Optional systems such as Trolley Plus allow increased lifting capacities in luffed positions, reaching up to 2,800 kg under certain configurations, enhancing the crane’s versatility.

Compactness is a defining feature of the MK 73-3.1, with a minimal slewing radius of approximately 3.3 meters without additional ballast and 3.5 meters with ballast, enabling operation within tight site boundaries. The variable outrigger system provides support widths of 5.75 meters and 7.0 meters, along with asymmetric configurations for restricted spaces, supported by an automatic setup monitoring system to ensure safe deployment. The ballast system consists of a base ballast of 4.3 tonnes with additional modules of 1.8 tonnes and 1.1 tonnes, resulting in a maximum total ballast of 7.2 tonnes.

The crane superstructure is driven by frequency-controlled electric motors, including an 18 kW hoist gear, 4.0 kW slewing gear, and 5.5 kW trolley travel gear, delivering smooth and precise operation. The electrical system supports external power connections of 400 V at 50 Hz, while the onboard generator ensures operational independence when external supply is not available. This hybrid capability, particularly emphasized in the MK 73-3.1E variant, allows for quieter operation and compliance with increasingly strict environmental regulations.

With an operating weight of approximately 36 tonnes and compliance with EN 14439 standards, the Liebherr MK 73-3.1 and its “E” variant provide a balanced combination of mobility, performance, and modern energy efficiency. The crane’s design, incorporating advanced control systems such as Micromove for precise positioning and Load Plus for optimized lifting performance, makes it a highly adaptable solution for a wide range of construction applications, particularly in urban environments where space, speed, and environmental considerations are critical.