Excavator EA-2621
The excavator Eo-2621, known in many regions of the former Soviet Union under the folk nickname of “Khan”, is perhaps the most famous earthmoving machine on the expanses of the former USSR. This all-purpose bulldozer tractor on the pneumatic-wheeled chassis belongs to the second size group (there are 6 such groups altogether). It is designed for development of various soils of the first to the fourth category.
The excavator EO-2621 successfully copes with any soil, from sand to heavy clay. Despite the fact that the extreme soil category for this equipment is defined as the fourth, effective work is also possible in difficult conditions if the working surface is loosened beforehand. The meaning of letters and numbers in the excavator name is as follows: “e” – excavator; “O” – individual bucket; “2” – refers to the second group (this includes excavators whose weight lies in the range from 6.3 to 10 tons); “6” – indicates that the excavator is installed on a serial tractor chassis; “2” – the excavator plant devices have a rigid bracket; “1” – is the serial model number assigned by the manufacturer.
Creation history
Manufacturers of the excavator “EO-2621” is not one, but several. Since 1967 these devices have been produced at “Chervonyi excavator” plant in Kiev and at “Zlatous” excavator (nowadays “Zlatex” Ltd.) in Shchelyabinsk region. And since 1974, also in Kyiv region – at Borodyansk excavator (nowadays – JSC “Borex”).
In addition, the production of this technique was established at a number of machine-building enterprises of GUS. Progenitors of this multipurpose earthmoving machine were quick-hitching hydraulic excavators E-201, which were based on the Soviet tractors: the Lipetsk T-30 and Minsk MTZ-2 “Belarus”. And later – its improved version “E-221”.
This equipment in its turn became the sequel of the first in the Soviet Union serial hydraulic excavator designed by the All-Russian Research Institute “Stroydormash” – rotary excavator E-153, created on the basis of MTZ-2 “Belarus” tractor. The manufacturer of this extremely necessary for the national economy equipment was the Kiev plant “Krasny Sackschnik”. Each of these models was designed for various agricultural and loading processes of medium and small volumes. And each was a new step forward, the embodiment of a number of improvements. Trenching depth, bottom cutting power and bucket angle were all increased. An indication of the then high demand of the Soviet Union for this equipment is that entire factories were converted into excavator factories to produce exclusively the above models. Especially engine repairs in Saransk; Or plans for a large shop at the Zlatoust Mechanical Plant, which was henceforth planned as Saransk Excavator Plant or plans to be.
A direct predecessor of the EO-2621 was the excavator E-2515, which in the basic version was equipped with a rear blade with a capacity of 0.25 m3; The maximum depth of the ditch was 3 m; Discharge height was 2.6 m; Capacity – 45-60 m3 per hour. This was vastly superior to all previous production models of foot-excavators. By the beginning of the 1970s, the growing Kiev city had already incorporated the red dredge into the city limits, encircling it by the perimeter around the residential areas. There was no room for the construction of new workshops, and they were built in the Kiev village of Borodyanka. As a result, the production of mounted excavator systems for tractors was completely moved there.
A few years later Kiev and Zlatoust were joined by Saransk, where mass production of EO-2621 was also set up. Up to “perestroika” and the collapse of the Soviet Union more than twenty thousand units of this equipment were produced annually. These volumes not only met the needs of the domestic market but also allowed to export excavators EO-2621 to 38 countries of the world.
Outstanding technical characteristics, cheapness of production and operation, reliability and unpretentiousness made EA-2621 the main tractor-based trailed excavator and the most popular in the world. This model is still produced in its modification “EO-2621B-3” and still stably keeps its cheapness and reliability on the market. Although, of course, the former production volumes is not the question.
Technical characteristics
- Capacity – 40 cubic meters. m/h;
- Digging radius: 5 m – backhoe; 4,7 m – straight shovel;
- trench depth – 3 m;
- dumping height: 3.3 m – straight shovel, forks and loading shovel; 2.2 m – inverted shovel;
- Standard bucket capacity: 0.25 cubic meters;
- Cutting power 25 kN for straight blade and 26 kN for rear one;
- Working cycle time: no more than 15 seconds for straight blade; 18 seconds – for backward blade;
- Load capacity when working with a hook – 0.5 t;
- hydraulic system – for excavator and bulldozer separately; working pressure – 10 and 7,5 MPa;
- Maximum height of hook suspension – 3,8 m;
- Jib outreach at maximum lifting height – 2,3 m;
- Belarus base chassis – tractor UMZ-6al/6am;
- Diesel engine, DT-65H, 65 hp;
- The maximum speed of movement – 19 km/h;
- The overcoming slope – 10 degrees;
- Track width of the rear wheels – 1550 mm;
- clearance – 450 mm;
- Overall dimensions in the transport position, 2DH – 6,48×2,2×3,8 m;
- Height in the cabin – 2460 mm;
- Weight with standard mounting equipment – 6100 kg.
engine
The excavator EA-2621 is equipped with a diesel engine DT-65N with an output of 65 hp. The excavator is equipped with a nine-speed manual gearbox with a reducer, which doubles their number. Totally EO-2621 has 17 front and 4 rear gears.
This excavator model is characterized by steering of worm type, supplemented with a hydraulic booster. The modern hydraulic section of the latest model of EO-2621B-3 has counteracting counters “Hydrocontrol” and built-in fuses, which allow to smoothly combine operations and increase the accuracy of work.
fuel consumption
The engine of excavator EO-2621, which makes the whole structure work, is designed for 65 h.p. And depending on the assigned load it consumes from 5,5 to 12 l/h. With a full fuel tank capacity of 100 liters, this reserve is enough for a whole work shift without any problems.
hydraulic system
The design includes two independent hydraulic systems, but with one fluid tank. The first hydraulic system drives the attachment from three NSH32-3 type gear pumps. Working fluid is supplied through the dealer to the hydraulic cylinders of the bucket, dipper and boom. The second pump system supplies hydraulic fluid to the boom and swing cylinder through the dealer, and to the outrigger and bulldozer cylinder through the tractor’s distributor.
All pumps are driven by reduction gears from tractor Diesel engine crankshaft. To limit pressure in closed hydraulic cylinder piston cavity when digging, there is a special bypass valve, which allows liquid to flow to hydraulic cylinder rod cavities and excessive liquid to tank in rod cavities. Fluid loss in the hydraulic cylinder rod cavities is compensated for by a check valve. Slight deceleration at the end of turns is provided by special damping devices installed in hydraulic cylinder caps.
Boom of excavator EO-2621
The boom of the trench shovel is mounted on the base of the slewing column. Due to such design the device can be used not only as a straight shovel and as a swivel shovel, but also as a tool for angle conversion up to 160 degrees.
use and purpose
Technical characteristics of the tractor EO 2621 allow to use it both in municipal and agricultural enterprises, as well as in industrial and construction companies:
- for agricultural work – pits, ditches;
- as a front loader – loading loose materials into trucks;
- for leveling the surface – curing the completeness of ditches and pits;
- Construction of embankments – loose or viscous materials, debris and disease development.
device
1 – bulldozer blade; 2 – bulldozer blade hydraulic cylinder; 3 – bulldozer frame; 4 – fuel tank; 5 – hydraulic system tank; 6 – pump group; 7 – excavator frame; 8 – hydraulic control valve; 9 – swing mechanism 10 – arm hydraulic cylinder; 11 – arm; 12 – bucket hydraulic cylinder; 13 – bucket; 14 – boom hydraulic cylinder; 15 – boom; 16 – connecting pipeline; 17 – rotary column; 18 – remote assistance hydraulic cylinder; 19 – remote assistance
The second name “YMZ EO 2621”, because it was created on the base of light and mobile model YMZ-6al (6 hours) and mobile model with economical engine and good traction. The initial model was not designed for such works, but thanks to the design solution – bucket with additional frame, which increased the weight of the excavator up to 6.1 tons, we managed to create a very ergonomic and inexpensive machine.
What are the innovations of excavators EO 2621 on the basis of YMZ and what are its parameters.
hydraulics. Two-circuit separate hydraulics: for the bucket 7.5 MPa and for the dozer blade 10 MPa is provided by six gear pumps NSH32-3. The oil intake consists of a tank. A modern system of Antica control and safety valves is installed for ergonomic use of small and smooth movement of the bucket (and other equipment) with a load.
Undercarriage. Worm steering supplemented by power steering. 9-speed manual synchronous gearbox with downshift transmission in 3 ranges (4 reverse speeds). The undercarriage of excavator EA 2621 is made on a reactive axle with a built-in hydraulic travel.
cab
The spacious cab with panoramic glazing allows visual control of all work functions in every situation. The controls for the planning sign and excavator equipment are tethered and attached to each other on either side of the guide machine workstation at the front and rear of the cab. They are all literally at arm’s length. In the cabins of both tractors, on which excavator equipment EO-2621 is installed, a traditionally powerful and productive ventilation system with efficient heating is installed. Excavator and leveling equipment is controlled by means of hydraulic control valves.
The operator’s seat can be rotated by 180° for excavator equipment control. In the normal position, the operator controls the tractor during travel, while in the reverse position he controls the excavator. To facilitate direct operation and maintenance of the equipment, the fuel tank has been moved to the front of the tractor.
Options and equipment
The basic configuration of all modifications consists of 2 blades of different purposes:
- Excavator blade 0.5 m³ assembled on the rotor crown;
- Bulldozer.
If necessary, hydraulic equipment is completed:
- Grifer of various modifications and permissible carrying capacity;
- Profile (narrow or wide) bucket 0,15 and 0,25 m³;
- Hämmer;
- Ripples;
- Tooth loosening;
- Excavator;
- Crane hooks. – A total of 22 types of attachments.
advantages and disadvantages
Pictured here, the EO 2621 looks like a typical Soviet tractor, but unlike many models in this class, the EO 2621 excavator shovel has advantages that are effectively used by small and large agricultural businesses and companies.
Overview Mobile Excavator EO-2621 – Technical Specifications
Model E O-2621 is a shovel-planning excavator, which is based on the “Belarus” YUMZ-6al/AM tractor.
Excavator E O-2621 is made according to the “workhorse” principle – universal, unpretentious, cheap and economical. Exactly this special equipment is needed to perform relatively small works in hard-to-reach areas of construction, industry or agriculture.
Based on these considerations, the technical characteristics of the EO-2621, which belongs to the 2nd group of excavators, are combined with a low fuel consumption. This is important because such special devices have to be constantly moved from one site to another. Good cross-country ability, operational safety and ease of operation are no less important. And also high maintainability in the field.
The idea of installing attachments on the light tractor UMZ 6 proved to be successful. This model, with a small economical engine of 65 hp, has a significant clutch weight, which positively affects the mileage. As standard, the tractor should not serve as a chassis for special devices. The problem was solved with an additional frame.
As a result, the clutch weight increased to 6.1 tons, it became possible to use a non-removable glider as a support. The excavator spoon can be attached to a special column so that its rotation angle is 160 degrees.
In particular, it should be determined that the problem of quick and easy replacement of working tools on the EO-2621 has been solved. Thanks to its universal shape, the bucket can be used not only as a reverser, but also as a straight shovel. Replacement of the operator and an assistant is made in 20 minutes right on the workplace. Simply place the bucket on the floor, detach it and rotate it so that the earring is 180 degrees. Then the hydraulic cylinder is transferred to additional brackets on the handles. That’s it!
In addition to the bucket that comes standard, the EO-2621 can handle 22 other interchangeable workers. Among the most commonly used are the lift bucket, the arm, the grab, the ramp, the narrow trench shovel, the crane hook, the backhoe (using it to dig ditches near buildings), the dentist, the charging jar, and various charts.
However, the main assessment of the quality of EO-2621 was given by consumers. Numerous positive reviews note that this is a reliable and economical excavator-bulldozer, which is easy to repair and operate, and its purchase and operation is inexpensive.
A typical example can be given as an illustration. A villager, who is not a tractor driver or an excavator operator by profession, bought an EO-2621 of 1991 year of manufacture, i.e. simply put. Moreover, the machine had a leaky hydraulic system. The man himself (!) installed special equipment, which made a worthless hydraulic cylinder rods for the bucket instead of the worn-out ones. The new hydraulic pump NSH-100 cost 35 000 rubles (!). This excavator-bulldozer has dug several ponds on Category III subsidies, where it continues to operate successfully. The machine paid back all the expenses in six months!
In the EA-2621, the first problems “burst” the hydraulics. Similar complaints were received on the chain drive of the boom rotation. After we installed the Italian hydraulic drive and anti-movement valves, the complaints from the experts stopped. Not too competent owners who have the EA-2621 literally looks like “a killer” would not change it for a similar equipment. Instead, they will ask how to repair it.
Technical features of the excavator EO-2621
- Type: Bulldozer Universal excavator, on the pneumatic chassis, 2-nd size group.
- Purpose: loading and unloading, including semi-liquid or viscous rocks, development of floors of I – III categories (without loosening), IV category and freezing (with preliminary loosening) and open pits, land leveling, construction and agricultural works.
- Capacity, cu. m. per hour: 40
- Depth of capture, M: 3
- For straight shovel – 4,7; for backhoe – 5,0
- Grip height, M: for backhoe – 2.2; for bucket, face shovel or straight shovel – 3.3
- Volume of the standard bucket, cc. M: 0.25
- Force of cutting, kN: backhoe – 26, straight shovel – 25,
- Maximal work cycle time, sec: backhoe – 18, straight shovel – 15
- Lifting capacity (hook), tons: 0,5
- Working pressure in separate hydraulic system, MPa: on excavator – 10; on bulldozer – 7,5
- Estimated hook, M: 3.8
- Approach of boom at maximum lever height, M: 2.3
- Engine (Power, hp/kW): DT-65N (65/41.5)
- Top speed, km/h: 19
- Maximum track width (rear wheels), mm: 1550
- camber, mm: 450
- Max. tilt, deg: 10
- Transportation dimensions (LWD), M: 6.48 x 2.2 x 3.8
- Total weight with workers, T: 6,1
Conclusion
Reading the above description and working properties, it is easy to draw the following conclusion. EO-2621 does not have any extraordinary abilities. But it doesn’t need them. The machine is designed for the daily performance of ordinary work. And it copes with the duties perfectly.
