Gantry Cranes, Bridge Cranes, And Overhead Cranes

By Author: yjcrane
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Gantry cranes, bridge cranes, and overhead cranes, are all types of cranes which lift objects by a hoist which is fitted in a hoist trolley and can move horizontally on a rail or pair of rails fitted under a beam. An overhead travelling crane, also known as an overhead crane or as a suspended crane, has the ends of the supporting beam resting on wheels running on rails at high level, usually on the parallel side walls of a factory or similar large industrial building, so that the whole crane can move the length of the building, while the hoist can be moved to and from across the width of the building. A gantry crane or portal crane has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse. Some portal cranes may have only a fixed gantry, particularly when they are lifting loads such as railway cargoes that are already easily moved beneath them.
Overhead crane ...
... and gantry crane are particularly suited to lifting very heavy objects and huge gantry cranes have been used for shipbuilding where the crane straddles the ship allowing massive objects like ships' engines to be lifted and moved over the ship. Two famous gantry cranes built in 1974 and 1969 respectively, are Samson and Goliath, which reside in the largest dry dock in the world in Belfast, Northern Ireland. Each crane has a span of 140 metres and can lift loads of up to 840 tonnes to a height of 70 metres, making a combined lifting capacity of over 1,600 tonnes, one of the largest in the world.
However; gantry cranes are also available running on rubber tyres so that tracks are not needed, and small gantry cranes can be used in workshops, for example for lifting automobile engines out of vehicles.
Electrical Overhead Travelling (EOT) cranes or Gantry Cranes are commonly found in factory applications such as steel yards, paper mills or locomotive repair shops. The EOT gantry crane functions similarly to an overhead bridge crane, but has rails installed on the ground and gantry-style legs to support the crane. Capacities range from 2 to 200 tons, and sometimes even greater capacities. Most are electrically powered and painted safety yellow.
When bridge cranes and Gantry cranes became more popular in factories in the late 1800s a steam engine was sometimes used as a way to power these devices. The lifting and moving would be transferred from a fixed line shaft. the picture on the right shows an example of system powered by a line shaft and steam engine. The overhead crane is from 1875, and was one of the first systems to be powered in such a way. This was produced by Stuckenholz AG, Wetter am der Ruhr, Germany. Design developed by Rudolf Bredt from an original installation at Crewe railway works.