Draglines are a fairly old type of excavator, still in the age of steam, not long after wire rope excavators were invented. Its characteristics are that the boom is long and there is no stick. The position and inclination of the bucket are controlled by the lifting wire and the pulling wire. The bucket cuts soil by gravity, which is suitable for excavating relatively soft materials below the stop surface.

The dragline is not flexible enough when loading the truck, the accuracy is not enough, and the efficiency is relatively low. This limits its application, and construction draglines are mainly used for underwater excavation. Larger draglines have found their place in open-pit mines, with extra-long booms that allow for a large working range and deep digging depth, ideal for overburden stripping in coal mines. In order to pursue efficiency. People make the dragline bigger and bigger, and the working weight increases so much that the crawler travel mechanism can't bear it. To this end, a step-by-step running mechanism is applied to the dragline to reduce weight.

1. The hydraulic system of the excavator consists of a total of 5 parts. 2. The energy device part. The device that converts mechanical energy into pressure energy of fluid generally refers to a hydraulic pump, if it is pneumatic, it is an air compressor, the power part; 3. Execution device part. A device that converts the pressure of a fluid into mechanical energy, generally referring to hydraulic cylinders and hydraulic motors; 4. Part of the control and adjustment device. Control and adjust the pressure, flow and flow direction of the fluid in the hydraulic system, such as relief valve, throttle valve, reversing valve, etc.; 5. Auxiliary device part. In addition to the above 3 items, such as fuel tank, filter, accumulator, etc.; 6. Transmission medium. A medium that transmits energy.

The overall structure of the single bucket hydraulic excavator includes power unit, working unit, slewing mechanism, operating mechanism, transmission system, walking mechanism and auxiliary equipment. The power unit of the single-bucket hydraulic excavator is mostly an upright multi-cylinder, water-cooled, one-hour power-calibrated diesel engine.

The high-speed hydraulic compactor is driven by the hydraulic system of the excavator and the loader, which can effectively deal with the weak grinding area of the dynamic compactor, and the effective depth can reach 4~10 meters. It is mainly composed of hydraulic system, high-speed oil cylinder, seals, sensors, controllers and other important components.

At the beginning of the new year, manufacturing tax cuts and fee reductions ushered in a "New Year gift package". On January 5, Li Keqiang, member of the Standing Committee of the Political Bureau of the CPC Central Committee and Premier of the State Council, said when presiding over a symposium on tax reduction and fee reduction, large-scale tax reduction and fee reduction are key measures for macro-control. Affected by multiple factors at home and abroad, China's economy is facing new downward pressure. We must promptly implement new and stronger combined tax and fee reductions to ensure a stable start to the economy in the first quarter and stabilize the macroeconomic market.