Mobile tower cranes combine the flexibility of an all terrain with a self-erecting tower, particularly well suited to lifting over obstacles on urban sites, setting up fast enough to take on multiple jobs a day. Some models, like the MK 88-4.2E, can connect to an electric power source on site, to lift without diesel emissions.
The cranes have found a role in niche markets around the world, including in the UK. With the latest model, Liebherr is aiming to open up their use in markets with more restrictive road regulations. The new MK 88-4.2E mobile crane is designed for operation with an axle load of less than 9.2t and a total weight of under 36.3t. This may facilitate approval and road use in markets with corresponding weight limits.
The 445/75 R22.5 tyres, which are wider than those on the previous model, fitted to aluminium rims, open access to further markets such as Australia, Denmark and the USA.
Whilst the boom system has been largely carried over from the MK 88-4.1E, Liebherr has redesigned the crane chassis and counterweight to allow for lower axle loads: the counterweight is divided into several sections and is removable, and the outrigger beams can be removed easily.
Self-ballasting is available as an option: the counterweight can be fitted quickly and easily without an auxiliary crane. Depending on the distance to the ballast transport vehicle, the crane lifts the counterweight onto the chassis in two or three lifts. To enable the entire ballast to be fitted and removed, the ballast cylinders are integrated into the chassis. This solution is new for MK cranes.
A new option makes it possible to operate the crane electro-hydraulically whilst it is being supported and ballasted on site. Using on-site electricity or an external battery power pack, these steps are carried out locally without producing any CO₂ emissions.
Emissions free operation of the crane—and other plant—is often stymied by a lack of suitable site power. The new MK can now make use of 16A power sources, mains power, as well as more commonly relied upon 32A and 63A sources.