Heavy knuckleboom hits the road

Even before EN12999:2011 was published in April this year, knuckleboom manufacturers were well aware of what would be required of them to keep their cranes compliant with the standard.

Spurred on by an accident that occurred in June 2000 when crane operator Adrian Wood was crushed by an overturning knuckleboom during operation, the UK HSE joined the EN12999 A3 working group (as it was called then) to improve safety standards for loader crane operation.

The accident occurred when the operator was transferring a load to a trailer from the knuckleboom without taking into account the ballast weight being reduced with every lift. As the load, acting as a ballast weight, decreased, the crane overturned, killing the operator.

The result was a new set of requirements for knucklebooms including audio and visual warning systems indicating boom height and whether stabilisers were locked into position, and a rated capacity limiter capable of monitoring stabiliser deployment.

These changes to the EN12999 standard were the next necessary step after the Essential Safety and Health Requirements (ESHRs) of the Machinery Directive 2006/42/EC December 2009 were revised, to align the two standards.

Although the revisions to the ESHRs of the Machinery Directive were not specifically targeted at knucklebooms, many would agree that the driver for these changes was partially the trend towards larger capacity pieces of machinery.

This trend has also been evident in the development of knuckleboom technology as across the continents, manufacturers move towards building knucklebooms with higher load moments and longer reaches.

As a result of this, knuckleboom use in some countries is starting to diversify beyond the typical uses traditionally associated with these cranes.

In the UK, which has long been one of the strongest world markets for knuckleboom crane use in Western Europe, demand for the cranes seems to be strengthening further still.

Lorry loader industry trade association Allmi’s technical director Alan Johnson acknowledges this, saying, “We’ve certainly seen a huge increase in the scope for use of knucklebooms. On job sites you are seeing people starting to use them a lot more of a variety of things for different sorts of construction jobs. That’s where manufacturers are seeing the demand for larger capacity knucklebooms.”

Britain’s domestic demand for knucklebooms has traditionally been relatively healthy, with a variety of users from builders merchants using the cranes for deliveries, to civil engineering contractors using knucklebooms for excavator spoil collection on infrastructure projects.

With larger capacity knuckleboom cranes being developed however, more applications and therefore prospects are presenting themselves for manufacturers targeting this market.

Johnson continues: “In the UK there is already this huge demand for ‘bread and butter’ knuckleboom cranes dedicated to one type of job. But from a UK perspective we’re still relatively unique, we have a large fleet used for dedicated tasks.”

“The scope (of application) is what makes the UK one of the most important markets for knuckleboom cranes.

Other markets, such as the US and Australia, have very different approaches to these types of jobs, using small pick-and-carry cranes or boom trucks instead. However, with current developments in knuckleboom technology their range of use is beginning to widen.

Turkish crane manufacturer World Power Erkin is certainly hoping that this is the case, as they have recently released a 150t capacity all terrain knuckleboom crane which it claims is the only one of its kind in the world.

The ER-450000 L-8, available as a four or five axle all terrain, has a long horizontal outreach of 47.8m when used with a fly jib attachment and 22.5m normally.

This in conjunction with its maximum load moment of 450,000tm leads World Power Erkin’s global sales manager, Güvenç Tokgöz, to believe it is the most powerful all terrain knuckleboom crane anywhere in the world.

He, like Johnson, also believes general construction industry use of knuckleboom cranes is increasing, but not just in the UK. In the Turkish firm’s domestic market it is finding that large equipment installation or relocation jobs make up a sizable portion of this new demand.

Citing a recent job where the ER-450000 L-8 was used to remove an 85t hydraulic press from a factory with 40m of headroom, too low to use a mobile crane for the job, Tokgöz says, “If the 150t knuckleboom crane wasn’t used on that job, the entire roof of the factory would have to have been removed totally to be able to get to the load, a roughly a 90t load.

At least a 500t capacity telescopic crane would need to be used there. That could take maybe two days to take off the roof, another two days to put it back on again. With a knuckleboom you can do the job in 4 hours, and much less money.

“That’s the main advantage of this crane, it makes machine relocation and lifting easy under low headrooms.”

“But there are other advantages as well. For example, knucklebooms are faster to set up and work with than hydraulic cranes. You can also extend and contract the boom during lifting operations as each boom section is independently hydraulically controlled. Also, you also have to work with a bigger radius with telescopic cranes. Positioning and placement during lifts using hydraulic telescopic cranes is made by luffing the boom, you have much more accurate positioning with a knuckleboom.”

The size of World Power’s ER-450000 means that axle loadings are within 14t per axle, which is greater than limits in most European countries will allow for, which is why the firm is investing in a 130t version that can accommodate this.

“Europe is still on the balance point,” says Tokgöz. “The economy is still increasing, but so slowly. But the European market is the most important for us.

“It is a strong market for knucklebooms and we must stay in it because the Middle East and Asian markets are not stable. We are hoping to increase our market share there by 10% this year.”

Although some of the disparate world markets for knucklebooms seem to be agreeing a common view of the knuckleboom crane, some argue that this realignment has only been a fractional one.

And while Tokgöz acknowledges this, he seems confident that the many drivers for considering alternative uses for the cranes will get the message through sooner rather than later.

World Power Erkin has seen a large increase in demand for higher capacity cranes, and the cranes’ scarcity combined with its versatility commands a premium.

According to Tokgöz, rental firms can make as much as five times more from knuckleboom hire than mobile crane hire for the same capacity crane.

“For example, if a telescopic crane does one job in one hour making €1, for the same capacity, a knuckleboom on one job for 1 hr will make €5,” says Tokgöz. “Lots of customers are coming to us directly as we are far and away the provider with the most developed cranes at these capacities. Knucklebooms represent a more profitable market for rental firms as they are more suited to specialised jobs.”

Features on the ER-450000 such as crab and terrain mode steering assist it’s manoeuvrability, making it a powerful tool on constricted job sites and even inside buildings. It can even use its extra long reach to perform lifts inside a building while it remains outside without going through a roof opening.

With this kind of versatility World Power is expecting big things this year.

“Demand in the domestic Turkish market is increasing. We expect it to increase by 15% this year.

“We do however intend to pay more attention to the Middle Eastern market and expect our market share to increase there by 15%. In Asia also we expect to see a 5% increase.”