At present, the classification of hoists is very complicated. According to the lifting principle, there should be two types: hydraulic type and mechanical type. Mechanical technology is almost eliminated, and now it is mainly used in floor-standing double-column and cart trench hoists, but now there is a small shear powered by airbags, which belongs to mechanical type. Structurally, hydraulic elevators are divided into column type and shear type. Column type is divided into two columns (floor gantry type), four columns and single column type (four combinations can be connected together). Shear type is divided into small shears (ordinary small shears and ultra-thin small shears), large shears (ordinary large shears, sub-shears and ultra-thin sub-shears) and runway machines (used together with trenches). Functionally, it can be divided into positioning elevator (with side skateboard) and maintenance elevator (flat structure); From the purpose, it can be divided into car lifts and motorcycle lifts, as well as floor lifts for 4S stations (lifting cars from the first floor to the second floor).