The crane mainly includes hoisting mechanism, running mechanism, luffing mechanism, slewing mechanism and metal structure. The hoisting mechanism is the basic working mechanism of the crane. Most of it is composed of a hoisting system and a winch, and some lifts heavy objects through a hydraulic system. The running mechanism is used to move heavy objects longitudinally and horizontally or adjust the working position of the crane, and is generally composed of a motor, a reducer, a brake and a wheel. The luffing mechanism is only equipped on the jib crane, the amplitude decreases when the jib is raised, and the amplitude increases when the jib is lowered. There are two types of balanced luffing and unbalanced luffing. The slewing mechanism is used to make the boom slew, and is composed of a drive device and a slewing bearing device. The metal structure is the skeleton of the crane. The main bearing parts such as bridges, jibs and gantry can be box structures or truss structures, or web structures, and some can use section steel as supporting beams.

First of all, in the operation process of the whole crane, these three operating devices are inseparable. Let's take the driving device first. On the special laying track, the driving device is installed, which is used for the operation of the whole crane. Among them, the source power is provided to the heavy trolley, which promotes the large trolley to move on the track, and the large and small trolley of the crane transfers the weight of itself and the external load slowly with the help of the support device. In this process, The safety device has been performing its duties and plays the most basic role in guaranteeing the safety of cranes and staff.

Simply speaking, the driving device of the crane can be divided into self-propelled driving device and traction driving device. Here we mainly talk about the traction driving device in the crane. Relatively speaking, the supporting device of the crane does not have a complicated structure and working principle, it is a single one.

The work type of the crane is closely related to the safety performance. For cranes with the same lifting weight, span and lifting height, if the working types are different, the safety factor adopted during design and manufacture will be different, that is, the types, sizes and specifications of parts and components are different. For example, due to the different working types of wire ropes and brakes, the safety factors are different (the light safety factor is small, the heavy safety factor is large), and the selected models are not the same. Again, like a 10t bridge crane, the power of the hoisting motor for the intermediate work type (JC=25%) is N=16KW, and for the heavy work type (JC=40%), the power of the hoisting motor is N=23.5 KW.

It can be seen from the above situation that if a light duty type crane is used in a heavy duty type place, the crane will often fail and affect safe production. Therefore, during the safety inspection, it should be noted that the working type of the crane must be consistent with the working conditions. Through the frequency conversion speed regulation system, the electric energy regenerated by the motor braking when the heavy object is lowered is consumed by connecting the braking resistor in the DC circuit of the inverter, so that the moving large, small cars and hooks can be quickly and accurately adjusted to the speed. down to 0.