
Overhead cranes are also called bridge cranes. They are a kind of crane that comprises a line and hook mechanism that runs along a horizontal beam which runs along two widely separated rails. Several overhead cranes could be found inside a long factory building and they may run along the building's two long walls, similar to a gantry crane.
Usually, overhead cranes consist of either a double beam or single beam construction. These can be made by using either typical steel beams or a more complex girder style. The single bridge box girder crane is complete along with the hoist and the system and is operated with a control pendant. Whenever the application needs heavier capacity systems for ten tons or more, double girder bridge cranes are more common.
With the girder box configuration, one major advantage is the lower deadweight with a stronger integrity of the overall system. One more benefit would be the hoist to lift the objects and the bridge that spans the area covered by the crane, along with a trolley so as to move along the bridge.
Overhead cranes are most commonly utilized in the steel trade. The steel is handled making use of this crane at each step of the manufacturing method until the product is shipped from the factory. The crane is also responsible for pouring raw materials into a furnace and hot steel is then stored for cooling using an overhead crane. As soon as the coils are finished they are loaded onto trucks and trains via overhead crane. The stamper or fabricator likewise depends on overhead cranes to be able to deal with steel inside the factory.
The automobile trade normally utilizes the overhead crane to be able to handle raw materials. There are smaller workstation cranes which are used to deal with lighter loads within work areas like in sawmills and CNC shops.
Bridge cranes can be found in virtually all paper mills. They are used for normal maintenance requiring removal of heavy press rolls and several machines. Some of the cast iron paper drying drums as well as various pieces of specialized machines weigh as much as 70 tons. The bridge cranes are actually utilized in the initial construction of the paper equipment in order to facilitate installation of these extremely heavy objects.
The cost of a bridge crane can be largely offset in many circumstances with savings incurred from not leasing mobile cranes when a plant is being constructed that uses lots of heavy process equipment.
The Rotary Overhead crane has one end of the bridge mounted on a fixed pivot and the other end carried on an annular track. The bridge traverses the circular area below. Rotary Overhead cranes supply improvement over a Jib crane by making it possible to supply a longer reach while eliminating lateral strains on the building walls.
Amongst the very first companies in the world to mass produce the very first steam powered crane was Demag Cranes & Components Corp. Following along came Alliance Machine, who is now defunct. Alliance holds an AISE citation for one of the first cranes in the United States market. This crane was used in service until around 1980 and has been retired into a museum in Birmingham, Alabama.
Since the early days, many innovations have come and gone, for example, the Weston load brake is now considered rare, whereas the wire rope hoist is still common. In the beginning, the hoist contained components mated together in what is now called the built-up style hoist. These super industrial hoists are utilized for heavy-duty applications such as steel coil handling for example. They are also common for users who want long life and better durability from their machinery. These built up hoists likewise provide for easier repairs.
Now, most hoist are package hoists meaning that they are built into one unit in a single housing. These hoists are usually designed for ten years of life. This calculation is based on an industry standard wear and tear when calculating actual life.
In the present North American Material Handling Trade, there are several governing bodies for the business. The Overhead Alliance is a group that represents CMAA, or otherwise known as Crane Manufacturers Association of America, HMI or also known as Hoist Manufacturers Institute and MMA or otherwise known as Monorail Manufacturers Association. The members of this particular group are marketing representatives of the member companies and these product counsels have joined forces to make advertising materials to be able to raise the awareness of the advantages to overhead lifting.