A boom is the steel arm of the crane that carries everything. Just behind the operator’s cab. The boom is the most essential part of the crane helping to lift to dozens of feet.
Almost all hydraulic truck cranes have a boom that have several telescoping sections. For example, some have a boom with 3 sections like a 70-ton Link-Belt hydraulic truck crane. When the load is lifted, the sections telescope out to the needed height. Some of them are even equipped with a jib (a lattice structure attached to the end of the boom.
The rotex gear is located under the crane cabin and let the cab rotate or turn the boom by using a hydraulic motor. For it to operate correctly, must be moving seamlessly from right to left and up and down. That is what the rotex gear is for. This allows the crane to move at odd angles and positions which may be necessary for the job it is being used for. It’s usually controlled by pedals inside the cab.
Outriggers are much needed to lift with a mobile crane to be successful. These give a solid base for the crane and are used to improve the stability of the crane throughout the operation. An outrigger can use hundreds of thousands of pounds into the ground underneath the crane.
A counterweight lifts the load easier to save energy. These are often used in traction lifts like cranes, elevators and fairground rides. It is a counterbalance.
The hook on the crane keeps the load attached to the boom and jib. It works together with a steel ball at the end of the jib o keep the lines tight when no load is attached to the crane.
The cable runs from the base of the crane, all along the boom and jib and extend to the hook and steel ball. Depending on the size and cables the crane has the cables can hold anything between 14,000 to 140,000 pounds
Information gathered from: coastcrane.com