Perhaps the most impressive feature of crane developments in recent years has been the move to gigantism, like those container cranes used at the new London Gateway container port which tower over 440 ft and can lift two containers at a time under fully automated control. But that impressive achievement is put in the shade by Liebherrs’ LR 13000 crawler crane used in the construction of nuclear power stations and refineries and in the pre-assembly of offshore steel structures. Weighing 700 tonnes, the crane reaches a height of 248 mt and can lift 624 tonnes.
Internal crane requirements, however, are much more modest, but innovation remains an ongoing experience. A good example is Terex Material Handling’s redesigned Demag KBK Aluline light crane system with improved ergonomics in mind. Reduced rolling resistance allows users to move loads of up to 2 tonnes by hand with minimum physical effort. As an overhead handling system, it allows creation of almost any size of suspension crane or monorail system. The new sections are also stronger and lighter, needing less supporting structure, for reduced installation time and cost. It is virtually maintenance free.
Another Demag crane which shows just how far control innovation has improved is a 6.3t SWL electric overhead travelling crane with clam shell grab sporting teeth and side knives at Sky Europe’s sustainable broadcasting facility. Used for feeding wood chip to a furnace via a conveyor, the crane lifts the biomass material from the sunken input area, after sensors detect replenishment is due, for deposit into the silo store. The crane has frequency inverter controlled drives to ensure precise load positioning and minimal load sway, cutting the chance of contact between the bucket grab and the storage area’s walls. The wire rope hoist has a special heavy duty rope guide designed to counteract side pull, fail safe bottom block operated hoist limit, slack rope detection and electronic overload protection. The grab is fitted with anti-derailment protection and there is radio remote control for use during maintenance.
For internal work, operators should not overlook the role forklifts and pedestrian stackers can play by converting them into mobile cranes simply by adding special attachments, particularly of the vacuum kind. Another lifting device to exploit new market opportunities over recent years is the scissor lift for loading bay operations. Easilift Loading Systems, for example, launched Double-Dok, a blend of dock levelling and lifting platform technology that presents a flexible solution to changing loading bay usage patterns. The market opportunity here came with the advent and sharp growth in double-deck trailers, because Double-Dok avoids the need to change the height of loading bays to accommodate double deckers.
Cranes in general involve special safety issues. The term thorough examination is widely known but not always well understood, especially in relation to in-service inspection. If, however, LOLER requirements are followed, both for thorough examination and in-service inspection, employers can feel reasonably easy that they have gone a long way to making certain that lifting equipment is safe to operate and that unsafe equipment is spotted and withdrawn from service before it injures or kills.
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