Trench bucket excavator: description, application, photo

Multi-bucket excavators are used in mining (gravel, clay, etc.) to remove rock. They are also used for profiling slopes of railways and channels, as well as overloading loose materials and waste rock. This technique can process soils up to the 4th category, which do not contain large stones (inclusions). A multi-bucket excavator works smoothly if the diameter of the inclusions does not exceed a fifth of the width of the bucket.

It is noteworthy that the surface of the face with this technique is smooth and does not need manual cleaning. In this article we will learn more about what a bucket excavator is.

Specificity of work

As a rule, multi-bucket excavators are used in places where there is a large volume of the same type of work concentrated on one site. The reason for this is simple - large dimensions of technology. To transport it from place to place for the sake of small tasks will be expensive and long, which means it is inadvisable. For small jobs that involve regular movement, there are small models of pneumatic or road excavators.

Types of multi-bucket machines

The technique is classified according to the following characteristics:

• In the direction of movement during operation. This can be excavators of longitudinal, transverse digging or rotary models.
• By the form (design) of the working equipment. There are chain excavators and wheel-bucket.
• By the method of supplying equipment to the face. Cutting the rock is radial in the vertical, radial in the horizontal or parallel in the vertical.

Proceeding from these signs, it can be concluded that the excavators are of several types. Let's consider each of them separately.

Cross-digging machines

This is a multi-bucket chain excavator, which can be on a caterpillar or rail track. Works by parallel or radial cutting. The chain can be directional (used in homogeneous soils for the extraction of minerals or the planning of large channels and depressions) or freely sagging (used in soils with inclusions). There are also excavators, the distance of the crawler track which can vary depending on the working conditions. They are used for digging and cleaning channels of drainage and irrigation systems.

Longitudinal digging technique

This is a trench bucket excavator. Happens on caterpillar, wheel-caterpillar, pneumatic wheel or automobile run. In turn, models of longitudinal digging are divided into those that work with the ring chain, and those whose working body is the bucket wheel (rotor). The first are used for digging trenches with a width of not more than 1.1 m and a depth of 3.5 m. The latter can dig deeper pits - 1.6-1.8 m.

Rotary full rotation

Typically, this type has a crawler. But sometimes there is a rail. The device is equipped with a bucket wheel and an electric drive. It can cut the rock radially in the horizontal and vertical planes. It is used to extract minerals that lie in the form of interlayers. It can be refractory clay and other materials. The bucket excavator (rotary) is also used for large construction and overburden work.

Advantages of multi-bucket machines

Despite the fact that bucket excavators are much more widespread, the multi-bucket excavators have a number of undeniable advantages that allow them to retain their positions in the market. Let's analyze these features:

• Continuous work on the excavation of the rock. Meanwhile, in the one-bucket apparatus, the period of direct soil sampling is a maximum of 30% of the total working time.
• If we compare a multi-bucket and one-bucket model with the same capacity, then it can be seen that a single-bucket machine is heavier and more cumbersome.
• The bucket excavator spends a mere 1 cubic meter of rock consuming much less energy than an apparatus of the same capacity, but with a single bucket.

• Working in a construction career, a multi-bucket device provides the possibility of both uniform mixing of the rocks of the extracted material and their sorting.
• Developing the soil, the bucket excavator processes the bevels. As a result, the recess receives an almost perfect cross-sectional profile. The single-bucket machine develops a notch by ledges and in each of them leaves a shortage.

Disadvantages of technology

However, there are parameters by which a single bucket excavator clearly wins. Perhaps, it is because of them that he is still leading the market. The bucket excavator has such weaknesses:

• This machine is a real gourmet, which is able to develop only a homogeneous soil of no higher than 4 class or with small inclusions up to grade 3. A single bucket excavator can work without any problems with any class and type of soil, including rock.
• A car with a single bucket is not fastidious to weather conditions, which can not be said for a multi-bucket version.

For clarity, let's analyze the couple with an example of a multi bucket excavator.

EM-251

This is a domestic device, which consists of:

• Running and power equipment, as well as mechanisms mounted on the non-rotatable frame of the belt conveyor, which is designed for dumping soil in the side or into the body of transport.
• Work equipment (chains with buckets) mounted on the frame-boom.

As the running equipment is a multi-bearing caterpillar. The internal combustion engine transfers the rotation of the driving gears via a chain transmission. Caterpillars have frames connected by means of semiaxes and balancing device to the main frame. It turns out that the main frame is based on the caterpillar at three points. This makes it possible to achieve good excavator throughput.

When the bucket chain and the excavator itself move, a vertical trench is formed. The soil taken up by the buckets through the hopper falls onto the dump conveyor. He, in turn, throws it aside.

Excavators multi-bucket trench chain models EM-251 can change the position of the boom relative to the frame. It rolls back along the guides, which allows you to change the degree of its penetration, and consequently, the depth of the trench. When transporting the unit, the boom is in the up position. The machine is controlled by a special console, which is located in the operator's cab on the right, near the gearshift lever. This allows the driver to follow simultaneously the movement of the apparatus and the operation of digging mechanisms.

EM-182

We will analyze one more excavator. Em-281 - so sometimes mistakenly called this model. It consists of:

• Travel trolleys with single-edged wheels. It is equipped with a removable frame, a carrying bunker, a trough shaft, a counterweight counter, a cab, a top of the bucket frame, and, of course, an engine with a transmission.
• The bottom of the bucket frame, which has two planning links carrying a chain with buckets.
• Jibs, which supports the system of channels and block suspension.
• Electrical equipment and lighting devices.

The excavator is controlled by three levers, which are located in the operator's cab. The first is responsible for the inclusion of the bucket chain. The second - for the course of the trolley. Well, the third - for lifting and lowering the arrow. The latter is held in position by the brake located on the worm shaft. The motor transmits motion through V-belts, the tension of which, as well as the angle of the pulley circumference, is determined by the position of the tensioning device. The main shaft transmits rotation through the chain transmission to the turbine. The ground, cut by buckets, is transferred to the bunker, and then enters the trolleys, transporting it to the destination.

Thanks to the lifting winch, the multi bucket excavator, the photo of which is shown above, can be used for both upper and lower parallel digging, during which both ends of the bucket frame are raised and lowered synchronously. Thus, the bucket frame moves parallel to itself. Buckets at the same time remove a layer of the same thickness at any height of the face. To perform a fan cutting, which involves the movement of only one end of the frame, it is lowered appropriately.

Conclusion

Today we found out what the multi bucket excavators are and why they are not so common as odnokovshovye. It is worth noting that the limitations on the performance of machines imposed by the type of soil are very conventional and different for different types of excavators. And the continuous improvement of multi-bucket machines and the introduction of new design solutions allows us to believe that soon all the shortcomings will be eliminated

Incidentally, continuous excavators are also conventionally referred to as continuous earth-moving machines, in spite of the fact that instead of the ladles, milling cutters or scrapers are the working organ.