Do you know the principle of crane telescopic boom?

The boom of truck crane is the most important part of crane. The crane uses the pulley block at the top of the boom to support the winch wire rope to suspend heavy objects, and changes the lifting height and working radius according to the length and Angle of the boom. Although the role of the boom is to suspend and transport objects, different boom structures and technologies make the performance and efficiency of the crane is very different.

1. Truck crane boom structure
The boom of the truck crane generally includes the main arm and the auxiliary arm. There are two types of truck crane main boom, one is the truss structure boom welded by profiles and pipes, and the other is the box structure boom of various sections. With the development of truck crane, the main boom of truck crane is mostly box structure, and only a few are truss structure.
The role of the forearm of the truck crane is to connect the forearm at the end of the forearm when the height of the forearm cannot meet the requirements, so as to lift the object higher. Spinnaker can only lift light objects. Generally, there is only one boom, and there are more than two folding booms or telescopic booms, among which folding truss booms are the most common.

2, truck crane boom telescopic principle
(1) The telescopic form of the crane boom is as follows:
1. Sequential telescopic mechanism -- each telescopic arm expands and expands in a certain order.
2. Synchronous telescopic mechanism -- the telescope relative speed of each telescopic arm is the same.
3. Independent telescopic mechanism -- each boom can be independently telescopic mechanism.
4. Combined telescopic mechanism - When the telescopic boom is more than three sections, any two of the above listed telescopic methods can be used for the telescopic mechanism at the same time.

(2) According to the technology of the telescopic mechanism, the truck crane can be divided into no pin hydraulic telescopic mechanism and automatic telescopic mechanism.
1. The advantage of needle-free hydraulic telescopic mechanism is that the arm length is convenient to change, the working arm length is many kinds, and the practicability is strong. The disadvantage is that the self weight has great influence on the stability of the whole machine.
No pin full hydraulic telescopic mechanism has different combination forms, can be multiple hydraulic cylinder and a row of rope, can also be a single hydraulic cylinder or multiple hydraulic cylinder and two rows of rope.
The characteristic of multi-hydraulic cylinder plus rope row is that the last telescopic arm is retracted by wire rope, and the other telescopic arm is directly retracted by the cylinder by multistage cylinder or multiple single stage cylinder or multistage cylinder or single stage cylinder liner. As a result, the section of the last telescopic arm varies more, while that of the other arm segments varies less.
2. Automatic pin expansion mechanism adopts single cylinder, interlocking cylinder pin and arm pin, using precision length measuring electronic technology. Its advantages are light weight, small influence on the stability of the whole machine, fast expansion speed, small changes in the section of the boom, good lifting stiffness, but the technical difficulty, high cost, the length of the boom is less. (From the inside out sequence)

Automatic pin type expansion mechanism has interlocking cylinder pin and arm pin, cylinder pin is designed on both sides of the boom, the arm pin is designed on the boom plane. Its advantages are simple structure, strong self-locking, the disadvantage is that the large deformation arm pin is difficult to pull out, need to be stretched back and forth to pull out.
After understanding the boom structure and telescopic principle of the truck crane, you can understand the key points of the performance of the truck crane. At the time of purchase, you can choose your own car crane products according to your specific work needs.