SECTOR REPORT Ӏ KNUCKLEBOOMS


KNuCKLINGDoWN


Knuckleboom cranes have found their niche as loader cranes for trucks. They are becoming quieter, greener and easier to use. Julian Champkin reports on developments.


Knucklebooms can be mounted on all kinds of chassis. On crawlers they generally count as mini- cranes - see page 28. On static mounts the small space taken up by their foldable jibs makes what is essentially the same concept especially well-suited to ships, docks, offshore rigs and the like where they are generally classified as marine equipment and can be fitted with deep-sea winches, pipe grabbers and other specialised maritime extras such as heave compensation. In these applications they


can reach very large capacities and sizes: Liebherr’s RLK series, intended for deep sea operations, goes up to 250t capacity and 7,500tm overturning moment. And they can be equally useful when mounted on railway cars – see the box p40. But the prime application, and indeed the name used by several manufacturers of these cranes, is as a loader crane. Mounted on a truck, either behind the cab as is usual in Europe, or at the rear of the vehicle – a layout more favoured in the US - it loads the truck, frequently with construction materials such as bricks, tiles or timber, at the yard and, more crucially, unloads it at the jobsite either onto the ground or, for those with longer booms and reaches,


36 CRANES TODAY


Liebherr’s RLK dockside crane: knuckleboom on steroids?


into a first or even second-floor area of the project. They are workhorses, perhaps


considered an adjunct of the truck – the operator is more likely to consider himself a truck driver than a crane operator and will spend much more of his time at


the wheel of the vehicle than at the levers of the crane control - but a vital adjunct nevertheless. As with almost all crane


sectors, recent developments in knuckleboom loaders include digital analytics and remote control. Electric power, as


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