Box Style Bridge Girder
An advantage to a top running double girder bridge crane is that you can build a new building with reduced overall height and still have the same hook height as a single girder crane, which would require a taller building.
Many things need to be considered when properly sizing a double girder crane; including the headroom or overall height that is available to fit the crane into (height from the crane rail to the lowest obstruction). The height available is important because the hoist and trolley ride on top of the bridge girders rather than being suspended beneath the bridge girder. This gives the best hook height of any overhead bridge crane option, giving you the maximum amount of lift (distance that the hook can be raised above the floor below) available.
When using a magnet as a below hook lifting device, a double girder industrial crane is almost always used. Please specify in your request for quote if a magnet will be used on your crane. Due to the large number of repetitive lifts that magnet cranes endure, they should most often be sized as a class D as a minimum and many times classed higher.
Our standard double girder bridge crane is CMAA Class C but these cranes are available in class A-E. For more information see CMAA crane classifications.
Top running double girder crane primarily utilize electric wire rope hoists, but in some special instances electric chain hoists can be used with a custom made trolley.