When some people think about a bridge crane, they may conjure images of large mobile units lifting and placing huge steel girders into place to build an expansion bridge across a body of water. Although these vehicles have their place in industry today, they are not bridge or workstation cranes. Workstation cranes are used indoors and here is a look at their importance, versatility and value to many businesses today.
Cranes in the Workplace
A crane is defined as a tool used to lift heavy loads and move them into position. They are not to be confused with hoists, but many people often make this mistake and here is why. Cranes and hoists perform similar tasks. For example, both tools:
* Can lift heavy things
* Lift and can rotate heavy loads
* Are sometimes used in the same industries
* May utilize hooks, ropes, chains, or metal lines
* Can be manually operated or motorized
* Can lift items vertically (up and down)
This is where the similarities end. Cranes can move loads from side to side (horizontally) while hoists cannot. Some cranes can rotate loads in different directions. A bridge crane uses a beam called a bridge which is supported by a runway (support beam structure).
Some equipment is mounted above the beams (top running) while others are situated below (underhung).
Does your building have limited headroom? If so, you may want to think about a top running model because it gives you the greatest lifting height. You can choose from a single or double beam model also.
Single girder cranes have the hoist mounted on one girder. With double girder models the lifting mechanism is mounted across two beams. A double girder unit will provide the most headroom. Because top running cranes are mounted over the runway they provide the most lifting power. If you have large lifting needs, this is the best choice.
Underhung models are mounted below the runway. This offers the surest tracking because the lifting mechanism is directly attached to the I-beam, which is basically supported by the entire building. Realignment is not required very often.
This kind of bridge crane comes with its own support system. They are often used when there is not enough support provided by the building itself. A free standing model works well when you have large loads and plenty of floor space to work with. Plus, they are relatively easy to mount.