On the Right Track: $55M SR 347 Expansion Over UPRR

Introduction of the Flat-Top Cranes

Wed June 08, 2011 - National Edition
CEG



With the new 285 EC-B 12 Litronic, Liebherr introduces its range of flat-top cranes to its U.S. customers. Like all the cranes in the EC-B range, the 285 EC-B 12 Litronic is designed as a modular concept, which guarantees compatibility of the tower systems within the range as a whole. As with all the 15 smaller models in the series, the central feature of the new flat-top crane is the compact head. This completely pre-assembled unit contains the removable cab, the switchgear cabinet, the jib folding frame, the slewing gear, the slewing ring with slewing ring support and the current collector. The 285 EC-B 12 Litronic is designed to ship in standard sea-freight containers.

To ease trucking, the counter jib is designed for transport convenience. The compact head can be transported by road standing upright, and the complete upper part of the 285 EC-B 12 Litronic can be moved with maximum radius using five trucks.

With the EC-B series, Liebherr offers the “Connect&Work” assembly system as standard. Pre-assembly of the newly-designed counter-jib can be carried out on the ground in just a few steps. Additional aids to easy assembly are the guying system elements, already located precisely in the assembly position, and the lifting eyes for raising with a truck crane. The connections to the jib and the counter-jib are provided with longitudinal holes for simple mounting. Quick-release fastenings and centering bolts also make it simple to bolt the jib and counter-jib in place. Additional assembly platforms at working height provide further help in bolting on the counter-jib pivoting section.

Rapid connection of the jib of EC-B cranes is achieved due to the “LiConnect” system, developed by Liebherr and protected as a utility model. The jibs are welded tight and securely connected using the rapid connection system. One centering pin and one locking pin in each case transfer the force in the lower chords by means of a positive-fit surface.

Without having to suspend the complete compact head, one lift is all it takes to set this central unit in place on the tower. The jib folding frame and the counter-jib guying move simultaneously into position. And to go into action on the site, the cab is simply pushed forward. As soon as the compact head is mounted on the tower and the electrical connection is established, it can already be slewed into the ideal assembly position.

For assembly on difficult ground or for smaller vehicle cranes, the compact head, pre-assembled at the production plant as standard, can also be divided into smaller units. All the drives on the 285 EC-B 12 Litronic are developments from the Liebherr Centre of Excellence for Drive Technology in Biberach, Germany, and also are manufactured there. Frequency converter drives are used exclusively for the hoist gear, slewing gear and trolley travel gear, fitted with the electric motors and control technology from in-house production.

The FC hoist gear units are provided with an integrated automatic load acquisition device, and offer a wide range of load and speed capacities. Due to the MICROMOVE fine positioning mode, the load can be held at revolution speed zero without engaging the holding brake, and also allows for extremely fine sensitivity in hoisting and lowering, according to the manufacturer. The fact that the motor management system is not disconnected until after the brake has taken complete charge of the load provides for even greater safety.

For more information, visit www.Liebherr.com. CQ