derrick(redirected from Hallen derrick)
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Related to Hallen derrick: Velle derrick
hoisting machine for lifting heavy loads and transferring them from one place to another, ordinarily over distances of not more than 200 ft (60 m). Cranes have a long reach and can lift loads to great heights.
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a load-lifting device. It is a cantilever boom attached by a pivot at the bottom to a mast or column and suspended from a cable at its upper end, so that it can move about its vertical axis and vary its angle to the horizontal. The load is raised and lowered by a hoist. The lifting capacity of the derrick is usually less than 10 tons; that of heavy-duty types may be as high as 300 tons.