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We are never guaranteed to have a good summer here in Ireland. This one seems to be following suit. Unpredictable weather makes harvesting cereal crops very difficult. If it gets very wet then the situation can drastically change. Prepare for the worst and hope for the best.
This applies in particular to the combine harvester. Dry conditions and low moisture are easy going for most combines. Damp straw, high moistures and wet ground exert all sorts of pressures on the workings of a combine harvester and the operator. Grain quality and harvesting at the correct time are big concerns for the grower after the year's husbandry.
Much can be done to make the combine hum sweetly along. Newer machines tend to be looked after by the dealer with yearly servicing and inspections. Older machines run on tighter budgets can all too often be run on a wing and a prayer or a hammer and chisel.
There is much that can be done to prepare a combine for the season ahead. For those less adept at things mechanical, even a thorough inspection could identify a problem before it becomes a real problem mid-harvest.
If the operator's manual can be found, there is an enormous amount of valuable information within it. All settings and adjustments crucial for smooth and trouble-free running are contained within the elusive guide.
The most common type of combine harvester used here is a walker machine. Typical cutting widths of older machines are somewhere between 10ft and 16ft. The ages of many out there are counted in decades, with an odd one hovering around the half-century mark. With some careful inspection and maintenance, most are capable of doing what is asked of them very efficiently.
Walker-type combine harvesters have evolved from stationary threshing sets. Add an engine, driven and steered wheels, a grain tank and unloading auger plus a header to a threshing set and you have a combine harvester.
So regardless of brand, size or age, all employ roughly the same principles of operation.
Here we take a look at a middle-aged machine starting at the front and working our way through the machine and out the back. On many machines, there are guides stickers or indicators around the body of it to show how much to tighten belts or where to check for grease.
With these plus the operator's manual and our guide, it is hoped that we can shed some light on the dark art of keeping a combine harvester running.
Words of caution first though - if in doubt, don't take the chance. That applies to all aspects of checking, maintaining, servicing or running a combine. A combine utilises a huge variety of drive systems to operate its workings. A modern Claas Lexion has up to 4,000 components.
If you're worried about costs, get a quote beforehand. An experienced dealer or mechanic should be able to give you a rough quote for the check-over and another quote for work needing to be done.
As mentioned earlier, the current-day walker-type combine harvester has evolved from stationary threshing sets of past times. The engineering has evolved so what we get today is a very sophisticated machine.
Machine design differs from manufacturer to manufacturer but at their core, the main elements remain the same. At the front is a header with reel, knife and auger which feeds a neck chain, which in turn feeds a threshing drum.
The threshing drum separates the grain and straw. Straw climbs the walkers until ejected out the rear of the combine. The grain undergoes a thorough cleaning and separation in the shaker-shoe. The heavier grains fall to the bottom, where they are transferred to the tank by an elevator with rubber paddles while the light grains and chaff are blown out the back by a fan. Once the tank is full, the grain is then transferred to a trailer by an auger.
So in a combine harvester, regardless of brand, there is a lot going on. On many, you can find almost every type of drive mechanism employed in agriculture. These include chains and sprockets using both precision and plain chain, belts and pulleys using single-, double-side and multiple-banded belts, bearings including plain, self-aligning, thrust, spherical roller, timber, and so on.
Sophisticated hydraulic, hydrostatic drives, variable speed belt and pulley drives, electrics and electronics systems are all part of modern day combine harvesters. Not forgetting the engine, which can come from any number of suppliers, either air- or liquid-cooled.
Checks
It is always advisable to run up a combine harvester first before attempting to do any work on it after winter storage. During the winter, it may have become home to a variety of rodents and their families. The larger variety in particular you do not want to come face to face with when working on same.
Running up a combine harvester beforehand with the header in place may show up any bearings that are beginning to fail, loose chains or belts. Obviously do not attempt to check any element of a running machine with anything other than your eyesight.
With it stopped and ignition/start system isolated you can begin your checks. A failing bearing will generate heat, which can easily be felt.
Picture 1
The cutter bar is where it all starts, and blunt or damaged knife sections will cause dragging and bulldozing, especially if the ground is soft. Traditional knife sections are riveted in place but newer, bolted versions are very handy and easy to replace when conditions are tough. Once the knife has cut the crop, it is the auger which then brings it to the middle and feeds it to the neck chain. Broken, bent or missing fingers and guides can cause uneven flow to the neck chain and ultimately the drum. In good harvesting conditions you might get away with it but when conditions are damp it could cause a blockage and unnecessary downtime.
Picture 2
The combine's neck chain and slats deliver the crop to the drum and concave. Both are extremely resilient but bent slats/feeder bars can cause uneven feed to the threshing mechanism and will cause the chain to wear and break prematurely. Straighten or fit new slats as required. Adjust both sides evenly so that the slats are just touching the neck floor half way up the neck.
Picture 3
Once the knife has cut the crop, it is the auger which then brings it to the middle and feeds it to the neck chain.
Picture 4
The condition of the rasp bars on the drum and the concave will ultimately determine how well the combine threshes the crop. Rounded bars in the concave and worn rasp teeth on the rasp bars reduce a combine?s threshing performance. A wet year and bulldozing could see a few stones make their way to the drum, so inspect both drum and concave for damage and clean out the stone trap in front of the drum regularly.
Picture 5
The combine harvesters many different types of drive mechanism, such as belts and chains, may need adjustment from year to year to keep them tight and running trouble-free. This is particularly important in a tough, wet year where if one element of the combine becomes overloaded and may stop, causing a major blockage.
Picture 6
Many manufacturers will have these guide stickers placed all over their machines as a guide to adjusting belts or other mechanisms properly.
Picture 7
The combine's shaker shoe is where the grain and trash get separated. Check that the frog-mouth sieves adjust and function accordingly.
It is important to seal the grain pan to minimise any losses as the grain is transferred from the drum to the elevator. Winter vermin like mice and rats like to chew the rubber seals at the side of both.
Picture 8
The walkers transfer the threshed straw out the rear of the combine. Cranks front and rear give the walkers their movement to transfer the straw rearwards while also shaking any grains out of the straw.
Each walker will have a bearing at the front and rear. These may be sealed ball bearing units or timber block units. All need to be checked for function and operation.
Picture 9
Transferring the clean grain to the tank and back to the drum are elevator chains that are equipped with rubber paddles. These rubber paddles are a target for rats that can quite literally make a meal of them. Damaged paddles cause grain to leak back down the elevator, overloading the chain and risking it breaking. These chains usually require adjustment annually as well.
Picture 10
There are multiple warning systems, even on very old combines, and it is important that these are working and their operation is checked on a daily basis.
Again especially important if the conditions are tough. Being checked here is the blocked straw walker switch. Many defective monitoring and control systems can be repaired rather than being replaced (or left). David King Electronics in the UK (www.dk-electronics.co.uk) or BREIZELEC in France (www.mantagua.fr) are two firms than can repair most display/control units.
Picture 11
It may seem obvious but it is incredible how many forget to blow out the combine's radiator or engine if air-cooled. A combine's engine spends most of its life revved flat out and works extremely hard, much harder than the average tractor engine. Any hiccup in servicing the engine or cooling system could have disastrous consequences.
Picture 12
Again, harsh conditions are tough on a combine's drive mechanism and a failure of a bearing or belt could easily cause a fire. Rats also love to chew on the armour and insulation covering electrical wires, of which there is no shortage of in modern combines.
There are numerous fire extinguisher options but I have unfortunately found that for the inexperienced user the powder extinguisher blue label is the best all-rounder for general, electrical and fuel fires. It is easy to use even for a panicked user, and smothers fires very effectively.
A 5kg extinguisher (or smaller) is ideal for the cab and a second 9kg at ground level is the ideal combination. Your local fire extinguisher supplier will advise, supply and check extinguishers annually.
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