A crawler is a crane mounted on a tracked undercarriage (also called crawlers)that provide for the stability and mobility of the crane. Crawler cranes have some advantages and disadvantages from there design, his influences their choice for a particular usage (Task). The main advantages of a crawler crane over a mobile crane is that they can move about on site and perform lifts with a shorter set-up from arrival for the smaller machines, as the crane is stable on its tracks with no outriggers, thus requiring less space. In addition, a crawler crane is capable of travelling with a load. The main disadvantage of a crawler crane is that they are very heavy, and cannot easily be moved from one job site to the next without significant expense. Generally used on larger lifting applications. Typically, a large crawler must be disassembled and moved by several trucks, to be transported to its next location.
Crawler cranes range in lifting capacity from about 20 tons to 3500 tons.
The first crawler cranes were derived from steam cranes, with the early machines being multi-purpose depending on the Jib set up. Either being configured as a Crane, Dragline, Front shovel or Skimmer depending on application. The earliest steam cranes being rail mounted.
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Early Manufacturers Edit
- NCK (Newton Chambers Koering)
- Smiths (Rodley) of Leeds
Modern Hydraulic Cranes Edit
The use of crawler cranes has increased in recent times due to the increased sophistication of modern Hydraulic drive systems giving greater control. The ability to move has advantages on a lot of jobs against fixed tower cranes, and with large mobile cranes, due to the Area that the machine takes up being less. Modern crawler cranes also have a lot higher capacity with 200 ton being a common size. A lot ate used to support piling operations due to the ability to work on rougher ground and move about. Some are built or adapted for piling operations, by additional winches and hydraulic drives, and special booms or masts.
These have been developed into Supper Lift Versions for heavy lifting on Engineering Projects like Nuclear power stations, building proccess plant and Oil rigs, or lifting bridges in complete to avoid long tern disruption to road or rail traffic. These machines having lift capacities in excess of 1000 tons and lift hieghts of over 130m main boom and 60 m fly jib, giving nearly 180m of lift under the hook.
Modern Manufactures Edit
- American Crane
- ABG Cranes
See also Edit
- Coles Crane makers
- Cowans Sheldon (Rail) Crane makers
- Stothert & Pitt (Dock & Oil rig mounted) Crane makers
- Mobile cranes
- The History of Cranes
- Classic Plant Magazine
- Lincoln's Excavators, the Ruston Years
- Lincoln's Excavators the Ruston-Bucyrus years
- The Great Book of Mobile and Crawler Cranes (Crane Technology Hand book)