Overhead and Gantry Crane Basics
Overview:
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 A large 130t crane for lifting fabricated steel assemblies. |
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Industrial cranes mostly feature a permanent installation or
fixed guideway.
They are typically referred to as gantry cranes, overhead
cranes, or overhead bridge cranes. In A jib crane has one fixed leg, a cantilevered boom that rotates around the fixed leg, and a hoist/trolley unit that traverses the boom and lifts loads for placement somewhere else. A jib crane is helpful in a high-repetition lift process where an overhead crane would be otherwise tied up. Jib cranes are typically one to two tons, but sometimes reach five ton capacity. The reach or span of the boom does not typically exceed ten feet. When calculating a jib crane reach, it’s important to consider “end-approach”, or how close the hoist/trolley unit can approach the ends of the boom – space for the hoist/trolley machinery, which is typically 12”, must be accommodated at each end of the boom. |
 Three overhead cranes on one runway. |
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An overhead bridge crane operates on a raised and fixed track. Typically the height under and overhead bridge crane is 20’ or more. On an overhead crane, endtrucks are equipped with wheels to provide for moving the entire crane. A bridge girder (single or double) spans the rails, and provides support for the hoist/trolley unit. Finally, the trolley traverses the bridge girders and usually has a hoist mounted on it to lift the load with either chain or wire rope. Most bridge cranes are at a rated capacity of twenty tons or less, but it’s not uncommon to see cranes under one hundred tons from time to time. The largest recorded overhead bridge crane is 800 tons rated capacity. It was produced for Combustion Engineering of Chattanooga, Tennessee in 1964. It is not known if this crane is still in service after the sale to ABB Power. |
| A gantry crane is
similar to a bridge crane, but typically has legs at either
end of the bridge girders, which are then mounted with
endtrucks at the bottom of the legs to move the gantry along
ground-level tracks. Gantry cranes are more frequently found
outdoors where no raised runway is present. Also, small
non-powered gantry cranes are used in light duty
applications such as small machine shops or automobile
garages. These gantry cranes typically do not have a fixed
path, but rather have rubber tires. Click Here to Request Competitive Proposals |
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