Liebherr Takes North American Approach to Rough-Terrain Crane Design
October 26, 2016 - Twenty years ago, Liebherr-Werk Ehingen made the decision to focus its research and development efforts on the LTM all-terrain and LR crawler crane product lines. With the attention placed on growing these offerings, the company discontinued its LTL rough-terrain crane production, of which it had built about 430 machines in the 25- to 80-tonne range. Today, the company offers 38 different cranes in its LTM and LR product lines.
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Liebherr LRT 1090-2.1
Although Liebherr expects to maintain its worldwide market share with its ATs and crawlers, Christoph Kleiner, managing director of sales for Liebherr-Werk Ehingen, presumes there is little to no opportunity to increase market share by continuing with the status quo.
As a first step in strengthening and widening its footprint in the crane industry, Liebherr has grown its sales and service. It has expanded its direct sales and service in a number of major markets, closed gaps in its worldwide coverage, and upgraded existing branches. Expect a new service center to open in November in Saudi Arabia.
The next step in growth has been adding to its equipment offerings. Liebherr looked at its current industry footprint; the global economy, which is driven primarily by energy-related and infrastructure projects; and requests from customers to offer rough-terrain cranes. After three years of discussions with key clients from around the world, Liebherr will roll out two new rough-terrain cranes at ConExpo 2017.
Design Approach
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| Enlarge Image The Liebherr RT cranes were designed to be simple and safe. |
With 50% of the world’s RT cranes sold in North America, Liebherr needed to produce machines that would meet the needs of this market. It considered the size, price, boom length, boom system, technical requirements, and safety needs of crane owners in the United States and Canada. What the manufacturer came up with were two clean-slate-designed rough-terrain cranes.
By applying its KISS (Keep It Simple and Safe) philosophy to determine what the crane should look like, what components should be used, and how it should be assembled, Liebherr designed the LRT 1100-2.1 and LRT 1090-2.1 rough-terrain cranes to have a nearly identical chassis and turntable but vary in boom length, telescoping technology, counterweight, and lifting capacity.
Karl Stöhr, product manager and sales administrator for Liebherr-Werk Ehingen’s telescopic cranes, says the company started with 100- and 110-ton capacities because the North American market sees the 90- to 110-ton capacity cranes as the class with the strongest growth potential. “An RT machine in this class made by Liebherr is expected from many of our customers,” he adds.
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| Enlarge Image A single counterweight is located on the turntable. |
Stöhr says that during its industry research, the company received mixed feedback regarding the telescoping boom systems. Some customers liked the pin- and latch-style with higher load charts, while others preferred a full-power hydraulic boom with higher speed. Liebherr has an offering for both styles.
The 110-ton LRT 1100-2.1 RT crane features a 164-ft.-long, five-section telescopic boom with the Telematik single-cylinder telescoping system that pushes out the boom sections independently with a single cylinder and pins it to the telescopic section above. Operating the Telematik was simplified for operators, and only two telescopic modes—strong and long— are offered. They are preselected by pressing a button, then the joystick is pushed forward and the boom telescopes. The basic LRT 1100-2.1 has a second winch and rooster sheave as standard for two-hook operation. A 34.5- to 62-ft. lattice-type, swing-away jib is optional. It can be offset 0°, 20° or 40°.
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| Enlarge Image Both RT cranes are powered by a Cummins engine. |
The single-piece, 15.4-ton counterweight can be assembled and disassembled with a hydraulic ballasting cylinder, which is installed inside the front of the chassis and will be standard for the U.S. market. “As the entire counterweight consists of one slab only, chances of an incorrect ballast arrangement are virtually impossible,” says Ulrich Hamme, managing director, construction and development for Liebherr-Werk Ehingen.
The 100-ton LRT 1090-2.1 has a 154-ft.-long telescopic boom, and its full-power boom consists of a two-stage hydraulic cylinder and a rope extension system, similar to Liebherr’s smaller LTM all-terrain cranes. Two telescopic modes—strong and long—keep it simple for the operator.
Also for simplification, a single 13-ton counterweight is located on the turntable.
On both new models, the load chart selection is simplified, and the LICCON2 computer system supports safe operation when the cranes are working with a load or being setup. The standard 360° load charts are supplemented with the Liebherr VarioBase support-dependent load capacity system, which was developed for the LTM models and will be standard on the LRT Series.
“The biggest advantage of VarioBase is that for each support position a secured crane operation is possible,” Stöhr says. “On many narrow jobsites, there are obstacles, and supporting an extended base is not possible. With VarioBase, each outrigger position has its own optimal lifting capacity.”
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| Enlarge Image A cooler to keep drinks cold is standard in the new cab. |
Both machines feature a newly designed cab that is about 9 in. wider than Liebherr’s LTM cab. The windshield can be lifted opened in front for better jobsite communication, and the cab tilts 20°. Webasto auxiliary heating and air conditioning are managed through a new A/C control unit. A first for RT cranes, the cab’s standard integrated cooler keeps the operator’s drinks and lunch cold. A USB charger is also standard.
To reach the cab, there are four access points on the RT cranes: two on the right, one on the front, and one at the front with rails to make the climb to the deck easier. An electrically extendible platform improves safe entry into the cab. The flat deck features an aluminum cover.
Storage space includes a box at the front of the chassis and one on the side between the axles. There is room for an aluminum folding ladder behind the rear axle, and the design incorporate storage space for wooden or plastic outrigger pads.
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| Enlarge Image The design incorporates space for wooden or plastic outrigger pads. |
Regarding the power train, the two models feature a 264-hp Cummins 6.7-liter diesel engine that supplies 730 ft.-lbs. of torque. The cranes can be equipped with Tier 4-compliant engines for the U.S. and Europe or Tier 3 engines for other countries. “Cummins was strongly demanded by the big operating companies of the main target market in North America,” Stöhr says.
The powershift transmission from Dana offers six forward speeds and two reverse. Heavy-duty axles by Kessler are 11 ft. wide. The front axle is mounted rigidly, and the rear axle is designed as a pendulum axle for pick-and-carry capabilities. The LRT units also feature hydraulically actuated disc brakes, an innovation for mobile cranes. Large surface 29.5 R25 Yokohama tires are ideal for off-road performance. Operators can choose from three steering modes: front-axle only, all-wheel, and crab. Maximum travel speed is 15 mph.
The cranes can be serviced by accessing two newly designed control panels on the side of the carrier or from the crane cab.
During a transportation demonstration of the LRT 1090-2.1, Liebherr loaded the machine with its counterweight and other equipment on a six-axle Goldhofer trailer. The total weight of the crane was 121,000 lbs., and it measured 12’8” tall and 10’10” wide. For the United States and Canada, the transport weight is 88,000 lbs. with the counterweight removed. The outrigger shoes stay within the width of the vehicle and do not need to be removed for transport.
The RT cranes are built to one safety standard worldwide, with a load capacity chart that meets ANSI regulations, Europe’s EN 13000, Australian standards, and Russian GOST standards.
Ten prototypes of the LRT 1100-2.1 and LRT 1090-2.1 were built for testing, which is expected to continue until the middle of next year. Sales will start at beginning of 2017, and the first LRTs will be delivered in the second half of 2017. A fully equipped machine is expected to sell for less than $765,000.
