Mobile cranes and tower cranes are very different in their constructions and the ways in which they are used. In many cases, cranes in general have to be inspected at least once a year, although that isn’t set in stone for every type of crane, and some elements may have to be checked more frequently.
Most cranes will need to be inspected based on the frequency of their usage. Cranes that are operating more frequently, such as those in “heavy service” or “severe service” might have to be inspected at least once a month by a designated competent person, if not more often. Annual inspections are conducted by outside authorities to make sure that the company is up to code with the way in which they manage and maintain their cranes.
Both tower and mobile cranes have to be inspected by someone from the company as frequently as possible, but in the case of tower cranes, the main issue is the way they are bolted and held to the ground for stability. Keeping up with crane inspection training is very important to conduct crane inspections accurately and safely. In the case of mobile cranes, there are counterweights that stabilize the crane and that have to be checked and inspected frequently to ensure they remain mounted correctly. Inspecting for worn out or damaged sheaves and hoist drums can be one of the more important tasks in this regard.