What Is an Excavator Digger?

Excavator ^[1] , also known as excavating machinery, also known as excavator, is used to excavate materials above or below the bearing surface with a bucket, and load it into a transport vehicle or unload the earthwork to the stockyard mechanical.

Initially the excavator was manual. It has been more than 130 years since its inception to 2013. During this period, it has experienced steam driven bucket swing excavators

Common excavator structures include, power units, work units,

There are two types of common excavators driven by internal combustion engines and electric drives. The electric excavator is mainly used in plateau hypoxia and underground mines and other flammable and explosive places.

According to the size, excavators can be divided into large excavators, medium excavators and small excavators

According to different walking methods, excavators can be divided into crawler excavators and wheel excavators.

According to the different transmission methods, excavators can be divided into hydraulic excavators and mechanical excavators. Mechanical excavators are mainly used in some large mines.

Divided according to use, excavators can be divided into different categories such as general excavators, mining excavators, marine excavators, special excavators, etc.

Divided by bucket, the excavator can be divided into

Operating weight

Operating weight is one of the three important parameters of the excavator (engine power, bucket capacity, operating weight) ^[4]

1. Excavator is a fixed asset with large economic investment. In order to increase its service life and obtain greater economic benefits, the equipment must be fixed in terms of personnel, machines, positions, and responsibilities. When the job must be transferred, the equipment should be handed over ^[4]

1. Reason for "jump"

(1) Variable speed

The model is 35, which is a 3.5-ton bucket with a capacity of about 0.11 cubic meters ^[5]

Difference between scraper, loader, bulldozer, excavator

Loaders are generally seen in seaports and logistics centers, mainly for loading and unloading containers. Graders are used to level the road, remove snow, bulldozing, loosening soil, and other functions. Excavators are a common type of engineering machinery, mainly used for excavating soil, loading vehicles, demolition, digging ground, and gravel. Forklifts are mainly for shovel and snow. The applicable scope of loading is similar to that of excavators, but the operating conditions are limited and the efficiency is higher than that of excavators. Forklifts cannot operate in soft soil and difficult trenches. Generally, forklifts are wheels. Style. Bulldozers are mainly used for bulldozing, flattening, loosening, etc., so in many development places, you can see that the excavator and the bulldozer work with each other, and the efficiency is very high. Scrapers, as the name suggests, are shovel and transportation. Scrapers generally shovel the soil in their "belly" where there is a lot of soil. They can walk up to 500 meters to 2000 meters to unload the soil and place it in the soil. !! The loader is a self loading and unloading machine for loading bulk materials into vehicles or other equipment. The loader can also perform light digging work. By changing the corresponding working equipment, it can also perform bulldozing, lifting, loading and unloading of wood and steel pipes. Scrapers can be used as loaders, but loaders cannot be used as scrapers. Bulldozer A tractor-driven machine with a wide, blunt horizontal dozer blade for clearing land, road structures, or similar work.

When inspecting and excavating the rust cracks on the welding joints of the side panels of the motor arm, it is necessary to scrape off or grind the paint on the surface of the joints, and use a small hammer to lightly observe the joints when observing, if necessary, use a magnifying glass to observe.

Cause of crack

Causes of cracks in the excavation of the side plate of the motor arm: including the original weld seam itself with air bubbles, slag inclusions and micro cracks. When the excavator is overloaded, micro cracks will occur at the original weld seam and slowly expand: welding electrode during welding Cracks that do not match the performance of the plate: due to the large volume of the excavating manipulator, it is difficult to use reliable and effective heating and insulation measures. After welding, the hardened area of the base metal surrounding the weld has not been completely removed, resulting in a decrease in the strength of the weld: excavator During the operation, the vibration impact is large, and the uneven force on the weld causes the weld to crack.

2. Repair method

Preparations before welding: Remove greasy dirt, paint, rust, etc. from the cracks of the original weld with a hand wheel. Use a gouging machine to plan and cut away the cracks in the weld, and plan to the body of the side plate, and remove the hardened area of the base metal that was previously welded. After planing, use an angle grinder to smooth the cut (the inner joint is polished to a V-shaped groove). After cleaning and pink inspection, confirm that all cracks have been found and removed.

According to the existing maintenance conditions, E5015 (J507) or E5016 (J506) 5mm electrode is selected, baked at 350 ° C for 2h, and then maintained at 100 ° C to prevent the electrode from absorbing moisture. Take it as needed; welding current 190 230A. Due to the large thickness of the side plate of the excavator, the welded part should be preheated to 150 250 before welding; in the welding process, the welding can be carried out in segmented, symmetrical, and backward methods; it should be used continuously during the cooling of the weld The hand hammer strikes the weld metal to eliminate stress; when welding at the corner of the side plate, in order to avoid and fall arc defects, continuous welding should be performed to improve the stress condition of the connection.

After welding is completed, completely remove the spatter, welding slag and welding knobs. The remaining height of the weld shall not be greater than 2.5 mm. Detect the welding seam by magnetic particle inspection. Defects such as cracks are not allowed.

3.Anti-corrosion measures

Sand the welds thoroughly, derust and apply anti-rust paint. At the excavation construction site, for existing rusted welds, manual rust removal can be selected based on the actual situation. The disadvantage is that the labor intensity of the workers is greater and the labor costs are higher. Pickling and rust removal methods can also be used, which uses organic acids as The main base is compounded with composite materials such as corrosion inhibitor, surface active agent, rust remover, rust inhibitor and film-forming agent, and is prepared into an acid cleaning solution with rust removal, rust prevention and primer functions. Derusting and antirust purpose.

In addition, during use, attention should also be paid to keep the excavator in a clean and dry environment, maintain good ventilation, and remove aggressive gases and moisture in a timely manner.

The purpose of the regular maintenance of the excavator is to reduce the failure of the machine, extend the service life of the machine, shorten the machine downtime, improve the work efficiency, and reduce the operating cost. ^[4]

From the perspective of various sub-sectors, the sales value of construction machinery in the first two months of 2013 was 63.696 billion yuan, an increase of -12.59% year-on-year, and the growth rate was about 14 percentage points lower than in 2012. The sales value of the domestic machine tool industry was 110.23 billion yuan. , A year-on-year increase of 11.34%, a growth rate of about 1 percentage point lower than in 2012; the domestic heavy mining machinery industry sales output value was 135.176 billion yuan, an increase of 9.73% ^[5] .

Compared with the estimates we made in the fourth quarter of 2012, it can be said that the recovery of the strong-cycle industry in the first two months is far less than expected, and it is expected that the recovery of the strong-cycle industry in the next 3 to 6 months will still be difficult. The sales output value of electrical appliances in the first two months of 2013 was 0.61 trillion yuan, a year-on-year increase of 11.79%; the investment in domestic power supply construction in the first two months was 38.5 billion yuan, a year-on-year increase of -14.5%, and the highlights of power equipment were reduced. The rapid recovery of railway investment since the second half of 2012 has become one of the factors driving the weak economic recovery, but the cancellation of the Ministry of Railways will have a negative impact on railway investment in the short term.

Although the extent and duration of our economic transformation in the past two years is still far beyond our expectations, in the future we will continue to work hard to find new and dynamic areas and have the capacity and space for continuous growth in the context of this difficult transition. company of. Maintaining bullish rating on the industry, the risk is that the economic adjustment lasts longer than expected.