The working mechanism includes the lifting mechanism, operating mechanism, variable amplitude mechanism, and rotating mechanism, which are known as the four major mechanisms of the crane.

(1) The lifting mechanism is a device used to achieve vertical lifting and lowering of materials, and is any type of crane

It is an indispensable part and therefore the most important and basic mechanism of a crane.

(2) The operating mechanism is a mechanism that horizontally transports materials through the operation of a crane or lifting trolley. 

It can be divided into trackless operation and rail operation, and is divided into self-propelled and towed types according to their driving methods.

(3) Variable amplitude mechanism is a unique working mechanism of boom cranes. 

The amplitude changing mechanism adjusts the operating amplitude by changing the length and elevation angle of the boom.

(4) The rotating mechanism is used to make the boom rotate around the vertical axis of the crane and move materials in a circular space. 

Cranes achieve the purpose of transporting materials through the individual movement of a certain mechanism or the combined movement of multiple mechanisms.