Before we go any further on mobile crane stability, we need to look at the mobile crane itself. Pulling it apart and looking at how the crane is constructed gives us a different perspective on balance than looking at the machine as a whole. So, lets de-construct it.
There are three basic components of the crane: superstructure, carrier and boom. Each one of these has a center of gravity (CG) and each of the components will affect the center of gravity of the combined parts in the final crane assembly.
The superstructure, upperstructure or upperworks, is the revolving frame of equipment on which the operating machinery are mounted along with the operator’s cab. The superstructure typically supports the crane’s counterweight on the rear and the boom or other attachment on the front. The CG of the superstructure will remain the same relative position regardless how the crane is positioned. (more…)