Depending on the structure, lifting equipment can be divided into light and small lifting equipment, elevators, cranes and overhead monorail system. Light and small lifting equipment mainly include lifting pulley, sling, Jack, manual hoist, electric hoist and ordinary winch, mostly small size, light weight, easy to use. In addition to electric hoist and winch, the vast majority of human-driven, suitable for the occasion of the workload. They can be used alone, and some can also serve as lifting mechanisms for cranes. Some light and small lifting equipment, such as the lifting capacity of hydraulic jack has reached 750 tons. Lift mainly for vertical or nearly vertical movements, with a fixed take-off and landing routes, including elevators, lifts, mine hoist and hopper lifts. Cranes are multiple action lifting devices that lift and carry heavy weights vertically within a certain range.