Excavators, also known as digging machines, are earth-moving machines that use buckets to dig materials above or below the bearing surface, load them into transport vehicles or unload them into the yard. The materials excavated by excavators are mainly soil, coal, sediments and pre-loosened soil and rocks. Judging from the development of construction machinery in recent years, excavators have developed relatively rapidly, and excavators have become one of the most important construction machinery in engineering construction. The three most important parameters of excavator are working weight (mass), engine power and bucket capacity.
There are two common driving modes of excavators: internal combustion engine-driven excavators and electric-driven excavators. Among them, electric excavators are mainly used in flammable and explosive places such as plateau hypoxia and underground mines.
According to different sizes, excavators can be divided into large excavators, medium excavators and small excavators.
According to different walking modes, excavators can be divided into crawler excavators and wheeled excavators.
According to the different transmission modes, excavators can be divided into hydraulic excavators and mechanical excavators. Mechanical excavators are mainly used in some large mines.
According to the purpose, excavators can be divided into general excavators, mining excavators, marine excavators and special excavators.
According to the bucket, excavators can be divided into front shovel excavators, backhoe excavators, pull shovel excavators and grab excavators. The front shovel excavator is mainly used to dig materials above the surface, while the back shovel excavator is mainly used to dig materials below the surface.
1. Backhoe excavator Backhoe is the most common one we have ever seen. It cuts the soil backwards and downwards. It can be used for excavation below the shutdown working face, and the basic operation methods are: ditch end excavation, ditch side excavation, straight line excavation, curve excavation, keeping a certain angle excavation, ultra-deep ditch excavation and ditch slope excavation.
2. Front shovel excavator
Form of shovel action of front shovel excavator. Its characteristic is "advance, forcibly cut the soil". The front shovel has great digging force, which can dig out the soil above the parking surface. It is suitable for digging dry foundation pits with a height greater than 2m, but it must be equipped with an up-and-down ramp. The bucket of the front shovel is larger than that of the equivalent backhoe excavator, and the digging water content is not more than 27%.
For three kinds of soil, the whole excavation and transportation operation can be completed with dump trucks, and large dry foundation pits and mounds can also be dug. According to the different relative positions between the excavation route and the transport vehicle, there are two ways to excavate and unload the soil: front excavation and side unloading; Forward excavation and reverse unloading.
3. Shovel excavator
The dragline excavator is also called the electric shovel excavator. Its excavation characteristics are: "backward and downward, self-weight cutting soil". It is suitable for Class I and II soils below the excavation stop surface. When working, the bucket is thrown out by inertia force, and the digging distance is longer, and the digging radius and depth are also larger, but it is not as flexible and accurate as the backhoe. It is especially suitable for large and deep foundation pit excavation or underwater excavation.
4. Grab excavator
Shovel excavators are also called grab excavators. Its excavation characteristics are: "straight up and down, self-weight cutting soil." It is suitable for Class I and II soils below the excavation stop surface, and is often used for excavation of foundation pits and open caissons in soft soil areas. It is especially suitable for digging deep and narrow foundation pits, dredging old channels, dredging silt in water, or loading loose materials such as gravel and slag. There are two kinds of excavation methods: ditch side excavation and positioning excavation. If the grab bucket is made into grating, it can also be used to load ore blocks, chips, wood and so on in the lumber yard.
Full hydraulic full rotary excavator
At present, excavators account for the vast majority of all-hydraulic and all-rotary excavators. Hydraulic excavator is mainly composed of engine, hydraulic system, working device, walking device and electrical control. The hydraulic system consists of hydraulic pump, control valve, hydraulic cylinder, hydraulic motor, pipeline and oil tank. The electrical control system includes monitoring panel, engine control system, pump control system, various sensors, solenoid valves, etc.
Hydraulic excavator generally consists of working device, upper body and lower body. According to its structure and use, it can be divided into crawler type, tire type, walking type, full hydraulic type, semi-hydraulic type, full rotary type, non-full rotary type, universal type, special type, articulated type and telescopic arm type.
The working device is a device that directly completes the excavation task. It consists of boom, bucket and bucket. In order to meet the needs of different construction operations, hydraulic excavators can be equipped with a variety of working devices, such as digging, lifting, loading, leveling, clamping, bulldozing, impact hammer, rotary drilling and other working tools.
The rotary walking device is the body of the hydraulic excavator, and the upper part of the turntable is provided with a power device and a transmission system. The engine is the power source of the hydraulic excavator, so diesel oil can be used in convenient places, and motors can also be used instead.
The hydraulic transmission system transmits the power of the engine to the executive elements such as hydraulic motor and hydraulic cylinder through the hydraulic pump, and pushes the working device to move, thus completing various operations.