H aomei machinery is in he nan province famous concrete pump and other large construction equipment company, as we know, in the construction site, concrete pump can be seen everywhere, here we introduce the under frame structure of concrete pump according to the extension of leg supported pattern mainly divided into the following three types: 1, after scaling before swinging leg structure Before expansion after the characteristics of the swinging leg structure is in the front part of the rotary base connection type telescopic leg, leg connection at the back of the swing type, because this type of chassis structure combines the merits of the former two, reduce weight and has the advantage of narrow construction site, been adopted by more and more manufacturers. Type 2, swaying back and forth leg structure Type back and forth leg underframe structure of form, the leg is open around the base of the rotary hinge point moves to complete, working stability is good, structure simple, but in both sides of the pump truck must leave enough space, is limited by a certain job site. Due to restrictions on the size of the vehicle shape, and the stability of the vehicle work reasons, concrete pump manufacturers at home and abroad are mostly adopt this kind of structure form. 3, type telescopic leg structure before and after Scale before and after the leg leg also calls the XH type, refers to the base of the leg in rotary box within the framework of horizontal extension and retraction, concrete pump of left and right sides of the leg can show X grade separation, can also be parallel scale. Under the influence of pump truck width size, stretch the leg structure size and length is limited by a lot of, for the manufacturing precision of rotary base box frame the demand is higher, the weight of the whole structure and its chassis is relatively heavy, and USES the built-in oil cylinder, disassembling and maintenance difficulties, so in 37 meters above level series has few manufacturers use. Just in the early stages of development of pump truck used by most manufacturers, but because of its operation with more flexible space, now there is still a manufacturer in using this form of structure.