The country that is home to the highest number of self-erecting tower crane manufacturers is Italy. Companies here include FB Gru, San Marco, Alfa Gru, FM, GC, Benazzato, Gru Dalbe, Cattaneo, and Vicario. Last but not least is Terex-Comedil’s range of self-erecting cranes made by Ferro in Milan, which was acquired in 2001 and makes 500 cranes a year.

These manufacturers’ new product launches are often timed to coincide with the SAIE exhibitions, held each October in Bologna. For example, the largest model of Terex-Comedil’s new CBR Plus range, with a 36m jib, is expected later this year. Although we must wait until October to see their latest innovations, manufacturers in France, Germany and the UK have developed small and large self-erecting tower cranes over the past 18 months.

“Transportation continues to be one of the biggest influences for our customers when selecting their cranes,” says David Havard, Potain’s global product manager.

“Transportation costs obviously add to the price of a job, but the M series keeps these costs to a minimum, making the cranes suitable for even very short-term jobs.”

Self-erecting tower cranes help lift small loads of concrete and construction materials for low-rise apartment blocks and offices. They are generally towed to site, and unfold to their final position. The smallest tower cranes are usually up for the shortest amount of time, so their axles are permanently attached, usually to the crane mast. Larger self-erectors have detachable axles.

The latest model in Potain’s transport-optimised M series is the Igo MC 13, introduced at last year’s Bauma fair in Germany. This model lifts its maximum capacity of 1.8t out to a radius of 8.9m. There are two versions available, one with a 22m jib and another with a 20m jib. The 22m jib version can lift 600kg at jib-end, while the 20m jib version lifts 700kg at jib-end. The jib can be luffed to 20 degrees, giving a maximum height under hook of 21.5m for the 22m jib version and 20.7m for the 20m version. Its on-site footprint is 3.9m x 3.9m.

Masol of Ireland has redesigned its TC 25 trailer-mounted crane, which also has permanent axles. The TC 25 Mark II has a maximum lifting capacity of 2t, and at 25m jib-end it can lift 750kg.

The Liebherr HM series also has permanently-attached axles, “because carpenters have a job site for 14 days, not more, and they need axles in the machine to change them out quickly,” says Liebherr marketing manager Hans-Martin Frech.

Liebherr introduced the 22 HM last year, its second model in the range, after 2002’s 13 HM. With a new steering system, the 22 HM can be towed either with a drawbar or a fifth-wheel mount. Maximum load capacity is 2t, which it can lift out to 13.5m radius; at its maximum radius of 27m it can lift 700kg. This compares to the 1.5t maximum capacity of the smaller 13 HM, which lifts 500kg at 22m jib-end.

If the cranes are on the job site for two to three months, costs are too high for integrated axles, Frech explains. Many dealers rent 50-100 fast-erecting cranes and own five to 10 axles to transport them to job sites.

The axles are quite important to the total crane service, Frech says. Normal axles have a speed of only 25km per hour. Some so-called jobsite axles need to be driven even more slowly, and are not allowed to be towed on the road. Liebherr’s self-erecting axles can be towed at 80km/hr on roads.

In rental parks, there are often special trucks that tow the fast-erecting crane, and have a loader crane to install ballast. For example, the Munich, Germany, depot of crane rental firm Baukran Logistik runs four trucks for its self-erector fleet, says sales and marketing manager Ulrich Langenbein. The trucks carry a 30tm-class lorry loader crane, and the self-erector counterweights. Once the truck reaches the site, its crane installs the crane’s counterweight and then picks up the self-erector axles and drives them away.

Bigger self-erectors

Larger self-erectors that need towing are becoming much more sophisticated. Several recent models are adopting two traits of larger cranes: telescoping masts and jibs, and the ability to raise the boom at an angle. Frech says that telescoping masts are a useful feature in self-erecting tower cranes. “If you want to buy a tower crane, you want it to be a flexible machine. If you have a K crane for example, you can reduce the hook height, if you have a job site in a hall, or a job site under electrical lines, you can lower the crane and also verify the hook height.”

Liebherr’s latest telescoping-mast crane is the 26 K.1 lattice self-erector, launched at Bauma 2007. The 26 K.1 is an extension to the lower end of the K series of lattice self-erectors, intended for small house-building projects. It has a maximum load capacity of 2.5t and can lift 1t at 26m jib-end. A telescoping lattice tower raises the hook height from 14m to 23m. The jib can also be luffed to 40 degrees, giving a maximum hook height of 37m, which the manufacturer claims is unprecedented. With a slewing radius of just 2m, the 26 K.1 can be set up right next to buildings. These two features combine to make it good for roof renovation projects on congested or inner city sites, Liebherr says. All configurations are pre-selected via the control panel or using radio-remote control.

Potain’s 40tm-class Igo 42, launched in June, can reduce its jib from 36m (maximum capacity 1.1t) to 26m (capacity 1.85t). Maximum load is 4t. Potain has also adapted its Top Zone limiting system for the Igo product line, allowing operators to define working areas and preventing the crane from slewing or trolleying beyond the set boundaries.

Also new this year from Potain, launched at the ConExpo show in Las Vegas, is the Igo T 85. The T designation indicates a telescoping mast to offer variable working heights and this is the second model in the Igo T series to be introduced.

The first unit, the T 70, was introduced at Bauma 2007. Both models have a two-section telescopic mast whose height can be increased by adding auxiliary sections. The working height of the T 70 can be varied between 20m and 32m in increments of 3m or 6m. It has a maximum capacity of 4t and lifts 1.3t at its maximum radius of 40m.

The new Igo T 85 offers working heights between 20m and 35m. The jib can luff up to 30 degrees and, depending on mast configuration, can offer lift heights between 42m and 48m. Its maximum capacity is 6t, which it can lift out to a radius of 15.5m. The Igo T 85 can unfold its jib to various lengths. The crane can pick 1.25t at its maximum radius of 45m; with the jib unfolded to 40m, the crane picks 1.65t at jib end. The 20 LVF 15 Optima winch offers hoisting speeds of up to 65m/min.