Excavator EO-4121: technical characteristics

Excavator EA-4121

Excavator EO-4121 was the very first hydraulic excavator of the Soviet Union on the driven stage, which was put into mass production. It belongs to the 4th size group and was designed in such a way, that it operates with 0.65-1.5 cubic meters bucket capacity. EA-4121 is a typical driven excavator for the majority of the USSR construction sites of the second half of the 70-s and the end of the 80-s of the 20th century. Series production of this model and its upgraded versions EO-4121A and EO-4121B was carried out at Kovrovsky Kotlovod from 1974 to 1991.

The purpose of the excavator EO-4121 is the widest range of earthmoving jobs: excavation of soil, arrangement of pits and ditches, construction of new or cleaning of existing trenches, loading loose materials and small chloride rocks with a size of parts up to forty centimeters in diameter. “EO-4121” can perform excavation work with floors of I-IV categories – from light weight sand to permafrost and soils of heavy tone.

Creation history

The debut specimen of this earthmoving equipment was assembled in 1970. After extensive testing the serial production of excavators EO-4121 was launched in 1974 at Kovrovskiy excavator in Vladimir region.

Kovrov Excavator Complex or Kovrovets is the manufacturer of the first excavator in our country and in general one of the oldest enterprises of all household appliances. It was founded on the production base of railway workshops which had been operating on the Moscow-Nizhegorodskaya railroad at the Kovrov railway station since 1861.

In 1930 the workshops were transformed into a plant for repairing elongated foreign-made cars. And on April 21, 1931 the first Soviet excavator was built there, which became the ancestor of the huge family of Kovrovets excavators.

During the Soviet period and until now, Kovrovsky Excavator, is one of the leading and leading domestic companies in the industry. Over the years of its patronage about one hundred thousand units of earthmoving machines passed, and the number of different models and modifications reached 64 types. The excavator EO-4121 was used at the plant until 1991, and the models “EO-4124”, “EO-4125”, “EO-4224”, “MTP-71” (“EO-4221”) became its “offspring”. The modern embodiment of the concept of EO-4121 can be called excavator EO-4225-A progressive and perfect.

Today the Kovrovets Excavator Plant specializes in the production of full-turn hydraulic crawler excavators: “KIT-26”, “EO-4225A-071”, “EO-4225A-061” with a full range of attachments. Protocol and chargers are also produced.

Scheduled assignment

The crawler excavator EO-4121 is designed in such a way that they operate as trenches and pits of different depth. Creation of embankments from soil and other loose materials; Clearing of working areas from industrial waste; Loosening of solid ground masses; Grasping of canals; Fountain development; Wrecking of concrete structures; Loading and unloading of various materials.

The technology can cope with the bottom of the first, second, third and fourth density categories. However, the latter requires preliminary loosening, which can be carried out either with a hydraulic hammer downward or with one – – – – – – – – – – – – – – hard equipment.

In Soviet times, this model was often used on construction sites, but sometimes the work of this equipment was also observed in the industrial sector.

Technical Data

General parameters of the excavator “EO-4121”:

Cyclic formula – 4 to 4;
Length without a bucket – 4.9 m, width – 2.9 m, height – 3.060 m;
Crawler base – 2.750 m;
Crawler size – length – 2.93 m, width – 0.58 m;
Number of platform revolutions per minute – 6;
Platform width – 3 m;
Track clearance under the turntable – 942 mm;
Height of the axis of the arrow’s heel – 2.02 m;
Distance from the axis of the heel to the axis of rotation – 520 mm;
Weight with a straight shovel – 19.87 tons, with the backhoe – 20.9 tons, with the scheme – 20.9 tons, with the loader – 19.87 tons;
Speed of movement – 2.8 km/h.
Overcoming track gradient – 22 degrees;
Capacity – up to 150 cubic meters per hour.

Features of the shovel model:

Capacity – from 0.65 to 1.5 cubic meters;
Radius of the grave – 9,2 m (backhoe); 7,25 m (straight shovel); 8,9 (graphical); 3,75 m (loader);
Radius described by the platform tail – 3.13 m;
Depth of capture – 5,8 m (backhoe); 3,6 m (straight shovel); 3,2 m (schedule);
Charging height – 5 m;
Force on bucket teeth – 14,200 kgf;
Cycle time – with a straight shovel and loader: 16 seconds; with a backhoe: 20 seconds.

Depending on the type of bucket used, these data may vary slightly. Specific bottom pressure of excavator model EO-4121 is 63.6 kPa, minimum cycle time with an angle of rotation of 90 degrees – 18 seconds.

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engine

The EO-4121 excavators are equipped with A-01 and A-01m diesel engines of the Altai Motor Plant, Barnaul city. This is a simple in design and maintenance, unpretentious, good-quality engine which is still produced and installed in a number of agricultural, industrial and forestry road construction works.

The A-01 type supercharged diesel engine with six cylinders is equipped with a two-valve gas distribution mechanism on each cylinder. The arrangement of the cylinders is vertical. Mixed mode – direct fuel injection. The method of cooling is liquid.

When making the engine were used mussels from Spetschugun, working surface of which was processed by flat-ruler hinning; Pistons with three-member piston rings, optimized side surface profile and graphite skirt; Block cartridge with increased strength and improved cooling of cylinder liners. The engine has a solid motorcycle touring power (up to 12,000 mass).

Cylinder displacement: 11.15 l;
Rated power: 99 kW or 135 hp;
Cylinder displacement: 1-5-3-6-2-4;
Cylinder diameter: 130mm;
Stroke: 140 mm;
Compression ratio: 16.5 (+/- 0.5);
Nominal crankshaft speed: 1700 rpm;
Nominal torque figure is 25%;
Specific effective fuel consumption at rated power is 221 g/kWh (163 g/hp);
Relative oil consumption for trucking is 0.3% of fuel consumption.

The A-01 motor drives two hydraulic pumps with adjustable power. Both pumps are installed in the same housing and are controlled through the transmission. In addition, a PZHB-300V prognosticator is installed, which facilitates starting the engine at particularly low temperatures.

chassis

The undercarriage is a tracked mechanism in which each track is available for tensioning by means of a transmission from a single hydraulic motor. A hydraulic cylinder is responsible for tensioning the track belt. The chassis design incorporates devices with injury-free joints to greatly reduce pressure. This version is designed for use on water and weak soils.

The swivel mechanism includes a three-stage transmission, swivel gear and a hydraulic motor consisting of safety and distribution equipment, a twin pump and a control director. The capacity of the pumps mounted in the same housing can be set. The pumps themselves are started by diesel engines through a distribution gear. Spool distribution units are located on a rotating platform behind the cab.

The Caterpillar excavator EO-4124 is equipped with cast-rail tracks with crank hooks. Nowadays this solution is no longer used or is rarely used. However, it gives an excellent performance in terms of reliability and durability of excavators. The service life of the tracks in this design is generally two to three times longer than that of conventional tracks.

Hydraulic system

The hydraulic drainage drive includes: a double pump, sales and safety equipment, and a control unit. Hydraulic pumps with adjustable capacity, mounted in a single housing, are driven by a diesel engine through a transfer case. Coil distribution units are defined on a rotating platform behind the cab. The pressure of working fluid in the hydraulic circuit of excavator drives was provided at the level of 250 kg/cm, which was a record parameter both for the USSR and for Europe at that time.

device

This model is a driven technique, capable of performing many operations.

Important components of the excavator include crawler track, metal platform with the ability to rotate 360 degrees, driver’s cabin with control panel, work equipment, engine, hydraulic system and electrical equipment.

The EO 4121 excavator chassis is designed in such a way that each crawler can be made separately with a single hydraulic motor. Tensioning of the sticky belt is carried out by a hydraulic cylinder.

1 – bucket; 2 – bucket hydraulic cylinder; 3 – arm; 4 – hydraulic cylinder of the arm; 5 – liner; 6 – hydraulic cylinder of the arm; 7 – arm; 8 – swinging platform; 9 – chassis for roundup

The hydraulic system of this model did not test the pressure of 250 kgf/cm2 for the first time. The result was positive, because the capacity of the hydraulic system is sufficient to work with strong soils and frozen ground. The mobile platform of this multipurpose excavator is mounted on a reinforced subframe. A special roller mechanism is attached to it, which can be used to rotate the entire structure. There is a tilting tool, fuel and working fluid tank, driver’s cab, engine and swivel mechanism. There is a counterweight at the rear for stability when working with large loads.

Dimensions in transport condition:

Tracked undercarriage base, m 3.7
Length of tracked undercarriage, m 4.56
Free space under the turntable, m 1.1
Turning radius of the rear part of the platform, m 3.28
Length in transport position, m 10.25
Swing platform width, m 3,0
Height to roof of cab, m 3,0
Caterpillar chassis, m 2.4
Height in transport position, m 3.3
Width of opening under the undercarriage, m 0.46
Travel lane, m 0.99
Wide tracked undercarriage (at 600 mm track gauge), m 3,00

Working space

Maximum gravel radius at parking level 9.3 m

Maximum kinematic depth of the grave 6.0 m

Maximum height of the grave 7,7 m

Maximum unloading height 5.15 m

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cab

Since EO-4124 was the very first model of full swing excavator in the USSR, its designers were faced with the task of balancing it on a rotary platform. At the same time, it was necessary to create a significant advantage in the rear – this would significantly increase the power developed on the spoon. For these reasons, the cabin and the engine of the excavator EO-4121 are at a distance of two meters from each other, which looks quite exotic to us. We can also note that the 2 hood doors are in the back of the excavator, not on the side. There is also an additional counterweight installed there.

From a modern point of view, the cab is an ordinary “tin cab”, reminiscent of a “bird house”, with the most minimal amenities for the driver. However, it is equipped with ventilation and heating, heat and sound insulation, a padded seat, and a number of instruments and control levers. There are flybulls for lighting and signaling.

In most cases, excavator EO-4124 operates with a deep spoon with a capacity of 0.6 m3, which allows you to open loose soil. About 50 different attachments can be installed on the hydraulic boom: hydraulic hammers of different capacity, loading spoon, loose soil spoon of 1.3 m capacity and many more.

Interchangeable tools

EO-4121 excavators can be equipped with rotary or nonrotary shovels. A rotary shovel significantly extends the excavator’s range of application since it can be used not only for ground excavation and loading, but also for leveling the working face. The blade handle and hydraulic cylinder with reverse handles. The shovel consists of two jaws and two booms.

Front and back shovel buckets with a capacity of 1 cubic meter are designed for excavation of soils up to the fourth category, and the bucket with a capacity of 0.65 cubic meter is designed to work with crushed stone and loosened frozen ground. The 1 cubic meter loading shovel is used for loading of soils and materials with the volume weight up to 2.2 t per cubic meter, and the 1.5 cubic meter shovel – for soils and other materials with the volume weight up to 1.6 t/m3 The permanent equipment of “EO-4121” excavator includes a stick and some kind of shovel. The devices which are specially installed depending on the type and nature of the work to be performed are considered interchangeable. The list of replaceable devices of EO-4121 is as follows: backhoe with an arm of different length; profile bucket; straight shovel with a bucket; gripping mechanism; loading forks; hydrohammer; ripper; hydraulic shearer; magnetic disk; clamshell equipment.

Attachments on the excavator boom are adapted for operation with rotary and nonrotary attachments of various sizes and configurations. Shovel excavators are more functional, they are used for loading liquid and loose soil, precise cleaning of quarry walls.

The 0.65 m³ bucket is designed to handle hard or frozen rock. Removable teeth are made of hardened steel, resistant to abrasion, impact and crushing.

The 1 m³ shovels are used for digging holes and trenches in medium-density soil. Products with an open bottom are more productive. They are used in building dams and dikes, backfilling pits and ravines.

The 1.5 m³ shovel is used for loading loose materials with low density. It can be construction and household waste, dry sand and various mixtures.

It is possible to expand the capabilities of the technique by means of a grapple, magnet, hydraulic hammer, ripper and gripper.

modifications

In total, two modified versions of this crawler excavator were produced – EO-4121A and EO-4121B. The second modification was the most popular of them.

EO-4121B differs from the basic excavator by a reinforced boom, which expanded the range of application of the equipment. The machine was used for rock excavation and loosening. In addition, this change allowed the excavator to work with very heavy loads, which is also a big plus.

In the working process, the machine can use a hydraulic jackhammer, pincer grapple, and ripping equipment. All this allows the machine to perform stripping operations in frozen and rocky soils.

The driver’s cabin is mounted on rubber shock absorbers that absorb strong vibrations and shocks that occur during work. The cabin is also equipped with adjustable seat and transport air conditioner (optional).

reviews

There are few reviews on the Internet of people who have actually had experience working on the excavator EO-4121, but most of them can be reduced to one thing: the excavator turned out to be of good quality, simple, reliable and unpretentious.

In any case hydraulic excavators are more productive and easy to operate than excavators with cable control. Therefore, the development and introduction of the excavator EO-4121 significantly improved the production of excavation work on Soviet construction sites.

The feedback also notes that crawler excavators are more stable and safer than pneumatic-wheeled excavators. However, the speed of crawler excavators is extremely slow, and they have to be picked up from one site only with trailers from one site to another.

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The experienced shovelers of EO-4121 note that its design has a minimum number of parts (not to the detriment of functionality) and is very maintainable. It has a fairly high level of unification with many models of domestic and imported excavators (especially hydraulic ones). Thus, it is relatively easy to select the necessary spare parts for it.

The excavator cabin, of course, lacks comfort and ergonomics. When using the pedals, it is not always possible to reach the levers, and with the most correct control of the levers, the legs begin to rest against the glass. Such shortcomings, combined with the general discomfort of the “birdhouse”, force the excavator operator to work in an uncomfortable position and strain his back. This ultimately leads to a decrease in its efficiency and productivity.

Excavator EO-4121: technical characteristics

Excavator EO-4121 was the first in the Soviet Union hydraulic crawler excavator put into mass production. It belongs to the 4th size group and is designed for work with 0.65-1.5 cubic meters bucket capacity. EA-4121 is a typical tracked excavator for the majority of the USSR construction sites of the second half of the 70-s and the end of the 80-s of the 20th century. Series production of this model and its upgraded versions EO-4121A and EO-4121b was carried out at Kovrov Excavator Plant from 1974 to 1991.

About the history of the model and the manufacturer

Peculiarities of design and area of application of the EO-4121

The design of the excavator “EO-4121” includes a tracked platform with a swivel mechanism. The rotary part accommodates the working equipment (boom and bucket), control system, fuel tank, hydraulic system tank, diesel engine, three hydraulic motors, 5 hydraulic cylinders and other components of the hydraulic system, operator’s cabin and a counter-sleeve (counter-sleeve at the rear). -The platform is based on the chassis frame through the scooter support.

One of the hydraulic engines rotates the excavator platform and the other two separately drive the tracks. The undercarriage on this excavator is tractor-type, and the crawler belts are tensioned by a hydraulic cylinder. The main working equipment of the excavator includes: a backhoe with 0.3-1.25 m3 bucket capacity, a diagram, a straight blade and a straight blade with a turning shovel, a loader, a hydraulic cutter.

Excavator is designed to work in temperature conditions from t-40 to +40 degrees (in tropical version and-Up to +55 degrees). Due to different bucket volumes and versatility of platform, excavator “E-O-4121” efficiently performs not only earth works (ditches, pits and pits) through Vile or Grak); Fragile with hydraulic milling machine; loosening the ground with a removable tooth.

Engine of the excavator EO-4121

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A-01m engine. It is also produced for a wide range of special devices.

Cylinder displacement: 11.15 l;
Rated power: 99 kW or 135 hp;
Cylinder displacement: 1-5-3-6-2-4;
Cylinder diameter: 130mm;
Stroke: 140 mm;
Compression ratio: 16.5 (+/- 0.5);
Nominal crankshaft speed: 1700 rpm;
Nominal torque figure is 25%;
Specific effective fuel consumption at rated power is 221 g/kWh (163 g/hp);
Relative oil consumption for trucking is 0.3% of fuel consumption.

The A-01 engine’s high-pressure fuel pump is of the rinp type rather than the piston type. The injectors are installed with a multihole grabber. The air filter is of the centrifugal cyclone type. Starting is done by a single-cylinder starter engine, PD-10U, rated at 10 hp. It is fueled by gasoline with the addition of 1/15 engine oil.

chassis

Hydraulic system of the excavator EO-4121

The cabin of excavator EO-4121

Interchangeable tools

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The 1 cubic meter forward and backhoe buckets are designed to excavate floors up to the fourth category, while the 0.65 cubic meter bucket is for working with crushed rock and cut-up floors. The 1 cubic meter bucket of the loader is for floors and materials up to 2.2 t/m3, and the 1.5 cubic meter bucket is for floors and other materials up to 1.6 t/m3.

The permanent equipment of the excavator EO-4121 includes a stick and a type of shovel. Equipment that is specially installed, depending on the type and type of work performed at a certain time, is classified. The list of replaceable equipment of “EO-4121” is as follows: backhoe with a handle of different length; profile bucket; straight shovel with a bucket; capstan and oxide mechanism; charging; hydraulic hammer; cooling; hydraulics; magnetic plate; grapple equipment.

Technical specifications in numbers

General parameters of the excavator “EO-4121”:

Cyclic formula – 4 to 4;
Length without a bucket – 4.9 m, width – 2.9 m, height – 3.060 m;
Crawler base – 2.750 m;
Crawler size – length – 2.93 m, width – 0.58 m;
Number of platform revolutions per minute – 6;
Platform width – 3 m;
Track clearance under the turntable – 942 mm;
Height of the axis of the arrow’s heel – 2.02 m;
Distance from the axis of the heel to the axis of rotation – 520 mm;
Weight with a straight shovel – 19.87 tons, with the backhoe – 20.9 tons, with the scheme – 20.9 tons, with the loader – 19.87 tons;
Speed of movement – 2.8 km/h.
Overcoming track gradient – 22 degrees;
Capacity – up to 150 cubic meters per hour.

Features of the shovel model:

Capacity – from 0.65 to 1.5 cubic meters;
Radius of the grave – 9,2 m (backhoe); 7,25 m (straight shovel); 8,9 (graphical); 3,75 m (loader);
Radius described by the platform tail – 3.13 m;
Depth of capture – 5,8 m (backhoe); 3,6 m (straight shovel); 3,2 m (schedule);
Charging height – 5 m;
Force on bucket teeth – 14,200 kgf;
Cycle time – with a straight shovel and loader: 16 seconds; with a backhoe: 20 seconds.

Reviews about excavators “EO-4121”

In any case hydraulic excavators are more productive and easy to operate than excavators with cable control. Therefore, the development and introduction of the excavator EO-4121 significantly improved the production of excavation work on Soviet construction sites.

The price of a used “EO-4121” excavator

There are no new excavators of the brand EO-4121 today, because the production of this model was completed almost three decades ago. For the same reason there are very, very few used excavators on the secondary market – their purely physical age on the street is too old. “The EO-4121 from the 80s is offered for 80-100 thousand rubles for spare parts. The more expensive ones are offered for up to 300-350,000 rubles. The cost of conducting a labor lesson on the machine EO-4121 is in the range of 1,000 rubles (+/- a few hundred).

The analogues of model EA-4121 are excavators MPT-71, EA-4225 and EA-4125, newer and more perfect earthmoving machines, which came to replace it.