Gantry crane

Both overhead travelling cranes and gantry cranes are types of crane which lift objects by a hoist which is fitted in a 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 fro across the width of the building. A "gantry crane" has a similar mechanism supported by uprights, usually with wheels at the foot of the uprights allowing the whole crane to traverse.

"Overhead travelling cranes" and "gantry cranes" 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.

Variants

Container crane

A ship-to-shore rail mounted gantry crane is a specialised version of the gantry crane in which the horizontal gantry rails and their supporting beam are cantilevered out from between frame uprights spaced to suit the length of a standard freight container, so that the beam supporting the rails projects over a quayside and over the width of an adjacent ship allowing the hoist to lift containers from the quay and move out along the rails to place the containers on the ship. The uprights have wheels which run in tracks allowing the crane to move along the quay to position the containers at any point on the length of the ship. The first versions of these cranes were designed and manufactured by Paceco Corporation They were called Portainers and became so popular that the term Portainer is commonly used as a generic term to refer to all ship-to-shore rail mounted gantry cranes.

Workstation Gantry Cranes

Workstation gantry cranes are used to lift and transport smaller items around a working area in a factory or machine shop. Some workstation gantry cranes are equipped with an enclosed track, while others use an I-beam, or other extruded shapes, for the running surface. Most workstation gantry cranes are intended to be stationary when loaded, and mobile when unloaded.

Rail Mounted or EOT Gantry Cranes

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. Most are electrically powered and painted safety yellow.

ee also

* Container terminal
* New York Central Railroad 69th Street Transfer Bridge

External links

* [http://www.portvision.be/BrowseContent.aspx?groups=22 Gantry Cranes database at www.portvision.be]
* [http://66.113.177.216/product_category_detail.cgi?id_num=100 Overhead and Gantry Cranes]
* [http://www.hydro.power.alstom.com:80/home/equipment___systems/hydromechanical_equipment/crane/17950.EN.php?languageId=EN&dir=/home/equipment___systems/hydromechanical_equipment/crane/ Overhead Travelling Crane & Gantry Crane]
* [http://www.bordersecurity.com/gantry.htm Specialty Cranes - Gantry - Bridge Building Cranes - Launching Gantries - Tower Cranes]
* [http://www.gorbel.com/gantrycranes/adjgantry.asp Adjustable Steel Gantry Cranes]
* [http://www.naicranes.com/cranes/gantry_cranes.htm Gantry Cranes Description and Pictures - North American Industries]
* [http://www.pacecocorp.com/ Paceco Corp Home Page] – Portainer cranes
* [http://www.alliancewestern.com/cranes-basics.htm Gantry Crane Basics]