Excavator is a major construction machinery for excavating and loading earth and rock. It is widely used in construction, water conservancy engineering, road construction, surface mining and national defense engineering. In addition, some small and medium-sized general-purpose single-bucket wetland excavators can also be used for lifting, loading, grabbing, piling, drilling and other operations by replacing the working device.

Excavators are divided into two categories: circular operation type and continuous operation type. Wetland excavators are circular operation type, and their working cycle includes: excavation, rotation, unloading and return. Multi-bucket excavators are continuous operation type. Generally, this type of machinery has high productivity. It is a special excavator, suitable for use in large-scale excavation projects.

The basic types of single bucket excavators can be roughly distinguished by the following aspects:

(1) According to the power unit, there are three types: electric drive type, internal engine drive type and compound drive type, and the internal combustion engine drive type is more commonly used.

(2) According to the transmission device, there are mechanical transmission, full hydraulic transmission and semi-hydraulic transmission. The walking mechanism of the excavator with semi-hydraulic transmission adopts mechanical transmission. Most domestic tire-type hydraulic excavators are semi-hydraulic. A few excavators only use hydraulic transmission for working devices, such as large mining excavators.

(3) According to the walking device, there are various types such as crawler type, tire type, automobile type and suspension type. Crawler excavators are widely used because of their good passability and stability. Wheeled excavators have fast driving speed, good mobility, and can pass on urban roads. More and more medium and small excavators use this type. Automotive and suspended excavators are small excavators that install working devices based on automobiles or tractors.

(4) According to the range that the working device can rotate in the horizontal plane, it is divided into two categories: full-rotation type (360 degrees) and non-full-rotation type (less than 270 degrees). Most hydraulic excavators are full-rotation type. The working device of the suspended hydraulic excavator can only rotate about 180 degrees, which is a semi-rotation type.

(5) According to the structure of the working device, it can be divided into two types: articulated type and telescopic boom type. Articulated structures are used in most excavators, and telescopic boom excavators are used for leveling and cleaning sites, dredging rivers and other operations.