The Principle Of The Boom Extension Of The Crane

The boom of the crane generally includes two parts: the main boom and the jib. There are two main types of main boom, one is a truss structure boom made of welded profiles and pipes, and the other is a box structure boom with various sections. With the development of truck cranes, most of the main booms of truck cranes are box-type structures, and only a few are truss structures.

The boom telescopic forms of the crane are as follows:

1. Sequential telescopic mechanism – each section of the telescopic arm is telescopic one by one in a certain sequence.

2. Synchronous telescopic mechanism – each section of the telescopic arm is telescopic at the same relative speed.

3. Independent telescopic mechanism - the mechanism that each arm can independently expand and contract.

4. Combined telescopic mechanism – when the telescopic arm exceeds three sections, any two of the above-mentioned telescopic methods can be used for telescopic mechanism at the same time.

The advantages of the pinless full hydraulic telescopic mechanism are that the arm length is easy to change, there are many types of working arm lengths, and the practicability is very strong. The disadvantage is that it is self-important and has a greater impact on the stability of the whole machine. The pinless full hydraulic telescopic mechanism has different combinations, which can be multi-hydraulic cylinders plus one-stage rope row, single hydraulic cylinder or multi-hydraulic cylinder plus two-stage rope row.

The feature of multi-hydraulic cylinder plus one-stage rope row is that the last telescopic arm is telescopic by wire rope, and other telescopic arms are directly telescopic with oil cylinders by means of multi-stage cylinders or multiple single-stage cylinders or multi-stage cylinders and single-stage cylinder liners. Therefore, the change of the section of the last telescopic boom is larger, and the change of the section of other boom sections is smaller.