Grain harvester Niva SK 5 – description and properties

Niva SK 5 combine harvester

The Niva ST-5 combine harvester is a self-propelled harvester with a capacity of 5 kg/s, which has been produced in the USSR since 1970. At one time, the Niva SK-5 harvester was the most popular in the USSR and was a kind of “visiting card” of Soviet agricultural machinery. Now it has been replaced by more modern ones, such as the Akros 530 harvester.

It was born after a deep modernization of an older model SK-4, which worked in the fields since 1960. Production of the combine continues under the brand name Niva Effect 5 and in our time, and its popularity among domestic farmers is still very high. Many such harvesters continue to successfully mow and harvest bread on Russian fields, which confirmed the high quality of Rostselmash products.

Photo of Niva SK-5 harvester

With “Time in Step” designers Rostselmash went the way of increasing the convenience of the combine and abandoned the asceticism of the Soviet era. The cab of the new Niva SK 5 combine harvester, which was originally designed in the Spartan spirit, pleasantly surprises with its comfort. It became airtight and made of modern soundproof materials, which provides necessary conditions for effective work of the combine operator, which is coordinated with the work of others at the wheel of the MTZ-320 Belarus tractor.

Combine harvester Niva SK-5

Photo of Niva SK-5 combine harvester

1. Reel 2. cutting unit 3. Harvester 4. Finger-cleaner 5. Inclined chamber 6. Receiving racket 7. Stone operator 8. Dressing machine 9. Prefix c-Deci 10. Main deck 11. Jackpost 12. Straw-substitute (mere ) board 14. Finger (notched) grate 15. Top sieve 16. Extension of upper sieve 17. Bottom sieve 18. Name board 19. Grain augers 20. Spike auger 21. Grain elevator 22. Grain elevator 23. (Distributor shaft) Spike cutter 24. Extension board

Working principle

The rotating drum tilts the stalks, the cutting device cuts them, and the drum puts them on the cone snail. The snail inserts the crop and advances it with the finger device into the intake chamber, the floating conveyor of the intake chamber advances you into the threshing and separating device (MSU). The intake sieve absorbs the crop and brings it to the drum. Stones fall into the stone catcher under the action of the blades of the receiving grid. If the chamber of the stone trap is clogged with loose mass, the cut plants slide along it and get into the gap between the drum and the deck by the blades of the receiving racket, and the stones break through this cushion and fall to the bottom of the stone trap. The drum grinds the mass across the deck with its whips. The whips, striking the ears, dislodge the grain, which falls into the holes of the deck. To break the grain less, the whips have notches – riffs – attached to them, and they replace the direct impact with a sliding blow. The grain is less traumatized by this blow. As the reefs move the mass to the side, one side of the combine is overloaded, and the other underloaded. To prevent this, the beaters are set alternately with the left and right notches (reefs). As the drum rotates at high speed (about 1000 rpm for wheat), it accelerates the mass on the deck, the speed of the mass increases and its thickness decreases. To get a quality thermos, it is necessary to have constant contact between the beater, the ear and the deck, so that the gap at the MSU exit decreases (for wheat the entrance is 18 mm, the middle 14 mm, the exit 2 mm). . The ears, moving on the deck, hit the rung and release the grain, so that 100% of the grain in the MSU is threshed and about 80% is separated from the straw (separated). The remaining 20% of the loose grains go into the straw walker together with the straw and the stray ears. The grain passes through the deck, while the chaff and chaff fall onto the transport cleaning board. The crusher bits knock the straw off the drum and guide it to the beginning of the straw walker. The straw, loose grains and chaff are discharged onto the chute, loosened and transported back to the loader by the tiered surface and the circular movement of the wedges. As the mass loosens, the heavier ears (like straw) and grains fall down, the openings in the wedges and along the sloping floor move the wedges onto the cleaning conveyor, and the straw falls into the loader. Grain piles (grains, chaff, piles and small waste) arrive on the vibrating platform from the MSU and straw walker. Thanks to the gradient surface and the back and forth motion of the vibrating plate, the pile is moved back to the finger bed. The fine particles (grain, chaff and small ears) fall through the finger sieve and reach the beginning of the upper sieve, while the coarse particles leave the finger sieve and reach the middle of the upper sieve. The upper sieve consists of louvers, they are 2/3 open. All grains and small ears fall through them, and large ears go to the extension of the upper sieve, the chaff is blown by the blower into the fork, the ears lowered to the extension fall through their louvers and fall into the snail. All grains and small ears falling on the lower sieve are transported back by the stepped surface (diaphragm) and circular movements. Since the shutters are 1/3 open, only the grains fall through them and hit the slanting board, while the ears drop down and fall into the volute. The grain rolls down the slanting board and into the grain snail. The ezalchen from the back of the recess goes to the manager, then to the upper write-off (distribution) snail. From there, it goes to Jack Beater,

Then to the drum, for re-threshing. Grain The grain auger is fed to the elevator into the hopper. The straw entering the hopper is compressed by a condenser with an appertaining chamber. The inlet of the chamber is wide and the outlet is narrow, so the straw is compressed twice. The bruter directs the floors to the bottom of the cooper. When the cooper is full and the combine comes to a series of shocks, the combine operator presses the pedal, the shock is discharged. After threshing, the cooper closes automatically. Most harvesters now have a chopper instead of a mower. In the mower, the straw is chopped and scattered over the field or loaded into the vehicle along with the floor.

It is impossible to imagine the work of this model without such an element as the harvester of the NIVA SK-5 combine.

Technical characteristics of the NIVA SK-5 harvester	Characteristics	Measurement units
parameters
Dimensions (dimensions):	мм	7607
– length	мм	3930
– breadth	мм	4100
– altitude	кг	7400
weight)	engine brand
mmz/d 260.1.36	output	kWhp
114/155	л	300
Fuel capacity	Drum rotation speed	2900
rotating speed	Number of blades	64
PCS.	л	3000
Volume of storage hopper	Discharge rate	40
l/sec	м	2,6
dumping height	cleaning system
double – real	м	3,6
Straw set element length	м	4
Number of straw set elements	thresher
drum	м	0,6
Diameter of threshing apparatus	inclined chamber
sponsor	м	5

Threshing arm width

Combine harvester NIVA SK-5

Each combine harvester consists of five main parts: header, thresher, skies, chassis and engine. In addition, the combine harvester is equipped with a hydraulic system, drive mechanisms, controls and alarms. Combine 5 “NIVA” is an example of the classic scheme of the grain harvester, which holds three and planned and the opener.

Photo of the NIVA SK-5 combine harvester

Harvester crushes the mass of corn and transports it to the threshing apparatus of the combine. It contains a body, reaper, auger, drive and adjustment mechanisms. The body is hinged on a tilt chamber on the central hinges and suspensions. A length-adjustable hanger is used to prevent skewing of the turf relative to the drill. The base of the sod is a welded body. On the back there are removable supports that can take working or transport position. The working position of the support is used during installation, repair and storage. Below are copying shoes, which serve as a front support brains in direct author’s way of harvesting. The shoes can occupy one of 4 positions. Thus, the height of the stalks cut is adjusted.

Combine “NIVA” SK-5: technical characteristics

NIVA SK-5, one of the legends of domestic agricultural engineering. This little combine harvester was born more than 40 years ago and at one time was one of the most popular grain implements in the Soviet Union. Today Rostselmash produces a deeply modified version of this remarkable harvester. The new SK-5 has excellent production characteristics and is able to compete with foreign counterparts in its segment.

These harvesters are mainly used in small farms with small areas under crops. There, where the use of heavy, heavy-duty machinery is impractical. In these conditions, these machines are indispensable and as a consequence, the demand for them does not fall over the years.

History of the NIVA SK-5 combine harvester

Rostselmash factory is known all over the country, in the near and far abroad, and traces its history back to the beginning of the 20th century. From the assembly line of this special enterprise when “Niva SK-5” harvesters came out, now their modernized offspring are also produced there.

The history of this machine, which without exaggeration can be called outstanding, began in 1958. In June of this year, to be exact on the 12th of June, 27 brand new combine harvesters were given to the Ministry of Agriculture. These were the first SK-3 self-propelled combine harvesters, which were fully developed by the designers of Rustselmash.

Niva” SK-3 combine harvester

This event was of great importance. After all the enterprise had been producing only pull harvesters. Now the production of machines of completely different level, modern and productive was established in the country. In 1961 already 100,000 machines were produced.

The next stage in the development of the model took place in February 1962. The work began with the production of the updated SK-4, this model was 25% more productive than the previous one.

Combine “Niva” SK-4

1st degree diploma in 1963 in Leipzig, a medal in 1964 at the exhibition in Czechoslovakia and “Silver Cup” – the highest award in Hungary. Niva SK-4 is the most excellent grain harvester in the world.

Production of the last model of this series, “Niva SK-5”, started in 1973. This harvester was the basis for the creation of several highly specialized modifications, for example: a rice harvester to work on slopes up to 30 degrees.

In the future, the SK-5 was repeatedly upgraded. Until our days it has survived under the name “Niva effect”.

Technical features of the “Niva” SK-5 harvester

• The letters SK in the name mean “self-propelled harvester”, and the number 5 is their productivity, 5 kg/s. Let’s look at the rest of its features:
• Dimensions Length/Width/Height – 7607/3930/4100 mm;
• Weight – 7400 kg;
• Dreschwerk – drum, rotation – 2900 rpm;
• Hopper volume – 3000 liters;
• Hopper discharge, speed/height – 40 hp. / 2,9 м;
• Solom a-Schüttler – 4 keys;
• Cutting width – 5 m;
• Knife – 64 pcs;

Camera – Sponsor.

Engine of “Niva” SK-5 harvester

Harvester engine is like any other device. It ensures the operation of all systems of the machine and its movement. The combine SK-5 was equipped with five different engines: ÑÌÄ-17Ê, ÑÌÄ-18Ê of 100 hp and ÑÌÄ-19Ê, ÑÌÄ-20Ê, ÑÌÄ-21 of 120 hp.

All models are four-stroke four-cylinder diesel engines of serial design. The last three models mentioned above are charged models. The air is forcibly cooled before being fed into the turbine, so that more fuel burns efficiently in the cylinder, and power can be significantly increased.

Modern “Niva-Effect” has a more powerful D-260 with 155 hp. This engine has lower fuel consumption and a longer service life. The engine has a good torque reserve, which ensures reliable operation even under high load.

Combine harvester with CVT “Niva” SK-5

The Niva is driven by a V-belt. This means that the torque is transmitted from the engine pulley to the gearbox pulley via a V-belt transmission by means of a variator.

The variator is used to change the transmission in the belt. This is done by axially shifting the guide block window using a hydraulic cylinder. By shifting the disc to the left or right, the width of the current changes. Accordingly, the belt either advances deeper, which reduces its diameter, or it is pressed against the surface of the current, which increases its diameter.

The variator is controlled from the cab by moving the piston handle of the hydraulic distributor. At full forward travel the maximum speed, at rear – minimum speed.

Undercarriage of “Niva” SK-5 harvester

The running gear of “Niva” SK-5 combine includes an axle with leading and steering wheels.

• leading axle. It contains:
• transmission
• clutch
• differential
• transmission with brake
• two final drives

Wheels.

The clutch is mounted on the receiver disc of the transmission input shaft. The clutch drive disc is attached to the bait shaft, and the release disc presses it against the inside of the pulley with 12 springs. When the clutch is disengaged, a special clutch presses on the release levers, disengaging the slave disc from the release disc and transferring the rotation to the transmission.

Transmission. Equipped with three shafts and a set of gears. Two movable gears (carriages) are attached to the drive shaft. The first engages 1st gear and reverse, and the second engages 2nd and 3rd gears. After engaging the gear, the locking mechanism locks the gears.

The steering wheel axle consists of: rigid beam, knuckles, trapezium with hydraulic cylinder, wheels.

Wheel hubs are attached to the ends of the beam with pivots and trunnions. Hubs are attached to half axles with cone bearings.

Niva” SK-5 harvester reaper

• The purpose of this cutterbar is to mow and transport the grain to the threshing machine. It can be equipped with a pickup unit, whose function is to pick up mowed stalks from the rollers. The width of the cutterbar may vary and consists of the following elements:
• The cutterbar body with the shoes. All the working elements of the cutterbar are attached to it. The body is suspended from the tilt chamber by a ball joint and special hangers connected by springs which balance the body. The cutting height is adjusted by the shoes and can be 50, 100, 130 and 180 mm. The pressure of the shoes on the ground is adjusted by tensile springs ranging from 25 to 30 kgf.
• Kitchen sink The role of the roller is to bring and support the stalks at the moment of cutting, and then send them to the auger. Its base is a shaft to which are attached crosses, on which are fixed rake. The latter, in turn, is a tubular shaft with spring-loaded fingers.
• cutting device. Its task is to cut the stalks when combining. The device consists of a finger bar with individual fingers and riveted reciprocating knife blades, friction plates, clamping knives and a drive mechanism. The knife is driven by an articulated telescopic gear mounted on the fixture body.
• The snail holds the flow of stalks and feeds them to the floating conveyor belt. It is a cylinder with spiral belts welded to it in the left and right directions, which move the mowed stalks to the center as they rotate. There is a finger mechanism in the center of the auger that pushes the crop onto the conveyor belt.
• floating conveyor belt. This mechanism accompanies the crop from the auger to the combine. The conveyor is located in an inclined body. It consists of shafts with sprockets, driven and driven. As well as roller sleeve chains with steel rods.

Picker. Picks up the crop from the rollers and feeds it to the cutterbar platform. To install a pickup unit, the reel must be removed first. Used in case of split combine harvester.

Cabin and steering system of combine harvester “Niva” SK-5

In old Soviet-era models, conditions in the cab of the combine were very Spartan. There was forced ventilation, but it did not save from the heat, and then air conditioning became a pipe dream. However, it should be noted that the controls of the machine were located quite comfortably.

The steering column is directly in front of the operator. In the floor to the right of the column is a gear shifter, separate pedals for the brake, shock absorber pedal, clutch, and to the left is the parking brake. To the right of the seat are levers and switches to control various mechanisms and systems of combine harvester: cutterbar, thresher, hopper unloading, etc.

The seat is cushioned, with vertical and horizontal weight adjustment.

It should be noted that on modern models of combines cabin is much more comfortable. The upholstery and soundproofing are made of modern, high-quality materials. It is possible to install an air conditioner.

Steering.

The steering wheels are located behind the combine. The steering system is fully hydraulic with a hydraulic cylinder in the steering linkage.

Hydraulic system of the combine “Niva” SK-5

Combine has two hydraulic systems: the main and steering. The hydraulic system that drives the working parts of the combine is the main one. It consists of: a hydraulic pump NSH-32U, safety valves, directional control valve with seven outlets, two-way hydraulic cylinder of shaft variator, two hydraulic cylinders of reaper and reel lifting. Hydraulic control of air cleaning, stacker opening, hopper shaking.

In steering hydraulic system: NSH-10E pump, hydraulic distributor, dosing pump, power cylinder. Hydraulic tank for both systems 14 l.

SK-5 Niva harvester modifications

• Combine SK-5 Niva, repeatedly upgraded, consider the main modifications:
• SK-5A – has an engine with increased power of 120 horsepower.
• SK-5AM – power increased to 140 horsepower, gearbox shifted to the left.

SK-5M-1 – hydrostatic transmission was installed on this model.

• Niva” combine SK-5M-1
• SKP-5M-1 – could be equipped with a removable half-track for work on soils with high humidity.

SKK-5 – a steeply-sloping modification, capable of working on slopes up to 30 degrees.

A unique modification of the harvester for separation of pumpkin into pulp and seeds was recreated from a serial model by a group of enthusiasts.

Operation of “Niva” SK-5 harvesters

1. Over several decades of operation of these machines in our country and CIS countries accumulated a lot of experience. We just have to apply it to our analysis. Let’s see what experienced harvesters write about “Niva”.
2. I’ve been working with Niva for many years and I cultivate 300-400 hectares per year. Of these, 200 are my own, the rest are Kolyma’s. The combine harvester is 5 meters long, the engine is not supercharged. During a 12-hour shift I cultivate about 14-15 hectares a day. Many call such a volume impossible for “Niva”, but it is quite realistic, although, of course, it is not easy. Having turned on the air conditioner, it became much easier. And of significant disadvantages – only wear and tear belts, but it is not difficult to replace them.

I have a small area, 40 hectares, so I can do it in 3 days. I bought it 3 years ago, when I’m tired of renting a harvester every year, and it still makes me uncomfortable. It works for me 3-4 days a year, but my soul is calm, and it is worth a lot. But I took Niva only for very little money, which has long paid off. Machines are old, you often have to grab with your hands, but they do their job without faults. If you do everything on time, the car is usually unkillable.

Now let’s move on to the advantages and disadvantages:

• The pluses include:
• The machine has a relatively small size, which allows you to use it on small fields with difficult terrain.
• Good productivity and low losses.
• Good grain cleaning.
• Good maneuverability.

• Spare parts availability, low cost.

Wear of drive belts.

Very tedious process of setting the combine.

Buying a Niva SK-5 combine harvester: Equipment of your choice

The vast majority of these harvesters are already quite old, which can not but affect their condition. Therefore, pay attention to the condition of the frame and other structural elements, a lazy machine will cause a lot of problems in the future.

Check the mechanisms: the condition of the drum, open the side flaps, it is perfectly visible, you can assess the condition of the thresher and concave harnesses; Check the soil of the elevators, there should not be significant corrosion. Assess the condition of the engine and drive belt.

The price of a Niva harvester starts at about 100 on the aftermarket. Anything below that is disassembled one way or another. The price for a fresh harvester is about 1.3 – 1.4 million rubles.

Conclusion