Overhead cranes are designed in four types. These four types are divided in two categories. Selecting an overhead crane for your operations depends highly on the capacity, duty class and lifting heights you require. Here are some things you should know when it comes to selecting an overhead crane for your project.
The top running and the under running overhead cranes are the two most important configurations for overhead cranes and are also called underhung. In case of a top-running crane, the end truck rides on the top of the running beam. However, when it comes to an under-running crane, the end truck rides on the lower flange of the runway beam. Both cranes have their own pros and cons. An under running crane allows a better end approach for the hoist. This is advantageous because it allows the hoist to get closer to the end truck or end of the runway than is possible when using a top running crane. It is also beneficial in terms of price as the under running cranes are far less costly than top running cranes. Under running cranes are also useful when it comes to operations such as ability to transfer hoists along bridges to interconnected monorails. On the other hand, the use of top running overhead cranes has its own benefits. First, top running crane can lift heavier load which is an advantage it has over the under running cranes. It is also to be noted that the top running crane also had greater headroom compared to the under running crane.
- THE USE OF SINGLE GIRDER OR DOUBLE GIRDER
The singer girder or double girders are two other essential configurations for an overhead crane. Both single and double girders have significant use with top running as well as under running overboard cranes. The double girder crane is well-known for being a more supportive configuration than a single girder. However, there is no denying that it is also a little more expensive than the latter in terms of overhead cranes. Regardless of the price difference, the double girder is considered to be more efficient as it designs also allow for a greater hook height than the single girder designs as the hoist could be fixed on top of the bridge instead of under it. Even though single girder cranes are far less costly, their capacities lay lower than that of a double girder crane which is why the latter is chosen more for operations. When it comes to a single girder crane, the hoist usually rides the bottom of the crane girder in both top running and under running configurations unlike a double girder crane. The ramification of this is that it creates a wider cooperative envelop for the hoist and is a solution for applications where headroom is not large enough, whilst for a headroom larger in size will need a double girder crane to operate.