The lifting machinery used in the construction of bridge construction can be divided into three categories, such as light and small lifting equipment, bridge type lifting machine and boom type crane, according to the difference of its structure and performance. Light and small lifting appliances such as Jack, hoist, hoist and so on. Bridge type cranes, such as beam cranes, Longmen cranes, etc. Jib type cranes such as fixed slewing cranes, tower cranes, truck cranes, tires, crawler cranes, etc.
A lifting mechanism with vertical lifting and horizontal lifting of heavy loads within a certain range. It is also called a crane. It belongs to the material handling machine. The working characteristic of a crane is to do intermittent movement, that is, the corresponding mechanism of taking action, moving and unloading in a working cycle is alternately working.