Crane boom is one of the key load-bearing components for a crane, with weight accounting for 13%-20% of the overall weight, sharing a greater proportion for large scale crane, which is the critical technology for the development of cranes. It is to support the weight of rigid structures like lift wire rope and pulley block etc. and it can be tilted and extended/retracted to change the position of the boom head. The main crane boom usually consists of pulley block, boom sections and telescopic mechanism, telescopic cylinder etc.
The loads on the boom mainly include lifting load (considering dynamic load factor), deadweight load, horizontal force of object movement, various inertia forces and wind force.
Crane boom telescopic mechanism
The design of telescopic mechanism has great influence on the weight, length and lifting capacity. The telescopic mechanisms of the box boom are mainly of hydraulic-mechanical drive type. The telescopic forms for booms of three or more sections are as follows. Synchronous telescoping: two-stage wire rope row is driven by the first-stage telescopic cylinder, applicable to the telescopic mechanism on the crane boom of four sections, such as STC200S, QY25, STC250 and other products. Sequential and synchronous telescoping: two-stage wire rope row is driven by the double-stage telescopic cylinder to realize sequential and synchronous telescoping, applicable to the telescopic mechanism of five sections, for example, extending boom in STC750S, STC250H, QY100 and other products is achieved by using either cylinder or wire rope.
Telescoping of crane boom has five sections: two-stage telescopic wire rope row is driven to extend and retract in order by two inverted cylinders, applicable to the telescopic mechanism on the boom of five sections, such as STC250S, STC250H and other products.
