The lifting spreader beam or overhead crane is a machine used for lifting and transporting loads within a limited space, both horizontally and vertically.
This machine consists of a single or double main lifting beam, supported on two rails raised on posts, which can be part of the structure of the ship or can be placed for this purpose.
Another element of the overhead crane is the self-propelled trolley, which is supported on the main girder and is capable of moving along it. The trolley has to support a hoist on its own, which is the mechanism used to lift or move loads, investing the minimal effort.
The transverse movement is carried out by moving the carriage on one or two rails arranged on the main lifting beam. And the vertical movement is executed through the lifting mechanism: hoist.
The hoist’s lifting wiring is lowered between the two parts of the structure. For this reason, the combination of the movements of the structure with the movements of the trolley makes it possible to act on any point of a surface. It is delimited by the length of the rails and by the separation between them.
These rails which are also called displacement rails are almost in the same horizontal plane in which the bridge-crane trolley is and it is the height at which they are that will determine the maximum height with which it can be operated.
The operation of the lifting beams and spreader bars can be done in three ways: wired remote control, wireless remote control, and control cabin.
Types of overhead cranes:
In the lifting sector, there are different types of overhead cranes, but two main types can be distinguished:
– Monorail crane bridge: Its main structure is made up of a single load-bearing beam, making it a simpler and lighter system. This type of overhead crane is suitable for small installations with spans up to 28.5 m and load capacities up to 20 Tn.
If there are no pillars in the workshop, the best option is to install a suspended bridge crane. In this case, a stable and solid roof structure is necessary to support the load of the crane and guarantee work safety.
On the other hand, since the rail beams are hung from the roof structure, this type of crane allows you to use space efficiently, especially in areas with complicated structures.
– Double-girder crane bridge: Its main structure is formed by a double girder, so this type of crane has a high load capacity (up to 320 Tn) and a higher speed, offering the maximum hook travel along with maximum precision and movement safety.
For this reason, this type of lifting spreader beam is perfect for handling high-capacity materials and carrying out large installations.