Liebherr has worked with Kamag to develop an interface that allows standard Self Propelled Modular Transport (SPMT) units to be used as fully integrated suspended derrick ballast trailers for the 1,000 tonne LR 11000 crawler crane.
The development was carried out following a request from Belgian international heavy lift and transport group Sarens. It also involved close cooperation with heavy haulage vehicle/SPMT manufacturer Kamag. The benefit for companies like Sarens is obvious in that it has Kamag K24 SPMTs in stock at almost all of its outlets around the world and saves the need to purchase a dedicated ballast trailer which could be stood up for long periods of time when it is not required.
Liebherr has tested the basic concept in the past with other cranes in its range, but until now the SPMTs had to be controlled by a person alongside the trailer, communicating with the crane operator in order to ensure that the SPMTs track the crane’s movements, which made it a less than practical proposition, except in an emergency.
Sarens provided Liebherr with two K24 SPMTs for the development and testing programme, while Kamag engineers also became involved. It quickly became clear that the Liebherr Liccon and Kamag control systems had similar basic structures, making an interface between the crane and SPMT controls a relatively simple development. Kamag developed a special control box that ensures good communication between the crane and SPMT, enabling the crawler crane to precisely control the movements of the SPMT unit.
Liebherr product manager Jens Könneker demonstrated a fully functional solution in November which showed how the ballast trailer worked perfectly in tandem with the crane as it slewed, travelled or turned. Afterwards he said: “Everybody involved here is delighted with the good collaboration with Kamag and Sarens and the result is sensational.”
Sarens’ new LR 11000 is to be supplied with a suspended ballast pallet as planned, which is then placed on the SPMTs for those jobs which require a ballast trailer, using a special adapter. For lifts that do not require a ballast trailer the SPMTs can be used for their usual transport work.
Carl Sarens said: “All our requirements have been met and we are confident that this will deliver significant added value for future projects as a result of the operative benefits and flexibility.”