Liebherr introduced the 81 K, a brand-new fast-erecting crane of entirely new design, to the U.S. market at ConExpo 2011.
The 81 K is the first crane in its class to operate only in the two part mode — a new development called SPEED2LIFT, that defines a new performance standard in this market segment, according to the manufacturer. Since all the loads can be lifted in the two part mode, the time-wasting process of re-reeving is no longer needed.
The 81 K uses a simple, safe erecting procedure. The tower is raised and telescoped out with a single continuous erecting rope. The erecting process is supported by semi-automatic quick-connection locking between the tower and the slewing platform, and by jib guying rods. For efficient ballasting, there is a semi-automatic ballasting system. Only eight lifting movements are needed to install the ballast and make the crane ready for operation.
The 81 K sets a new standard for bottom-slewing cranes by its use of driveline and control-system technology previously found only on top-slewing cranes.
Safe, efficient load handling is ensured by continuously variable drives developed by Liebherr’s own driveline technology competence center. All drive assemblies on the 81 K are continuously variable, using the frequency control principle.
The pushbutton-selected fine positioning mode MICROMOVE reduces hoist speed to 25 percent, so that even heavy loads can be positioned accurately without the hoist gear brake being applied.
With eleven variable hook heights, the 81 K is an extremely adaptable crane, according to the manufacturer. As well as the standard 85 ft. (26 m) hook height, various configurations are possible without using the climbing facility to insert additional tower sections: four additional intermediate hook heights, a 30-degree steep angle jib position and a 45-degree angle to keep the jib clear of obstructions. If further tower sections are inserted with the climbing mechanism, six more hook heights up to more than 131 ft. (40 m) are available with the jib horizontal. Electronic load moment limiting (LMB) also helps to make load movements safe. It warns the crane operator in good time if the load limit is approached. Due to LMB, the new 81 K can be operated unrestrictedly into the limit zone.
Liebherr’s load moment determination system is in two independent sections. Precise measurements and accurately determined computing algorithms ensure that loads are moved safely. With this increased safety specification, the 81 K also sets new standards for this class of crane, according to the manufacturer.
For more information visit, www.Liebherr.com.
