The Disc Mower

Introduction.

Why a new mower? After having seen how little optimal other types of agricultural equipment are, I was curious about the state of the art with the mower. That became an interesting experience.
The scythe comes into use approx. 400 B.C. as a handy and energy efficient tool for cutting grass. The sickle bar mower as we still know it from combines was invented in the early1800 in USA and in the later years the disc mower are almost controlling the market.

What is wrong with the disc mower?

After having done a thorough study of the mode of operation, the grass stubble, the mowed grass and the whole technical solution as ĒeveryoneĒ use, my opinion about what is wrong can in short be summed up in this way: Almost everything. Let us start with looking at how a typical area looks like after use of a disc mower. (Some better and some worse).

The destruction of the stubble and the utility plants

The disc mower cuts and tears the stalks to pieces. First a picture of the area seen from a little distance. What we can observe is how large length difference there is on the stubble. It should have been quite equal high and been cut quite even. With so uneven stubble high will we already here could suspect a major harvest loss because if the shortest stubble is correct the longest isnít. After this disc mower it looks more like the grass have been pulled out of the field. When we look at the close-up the result is even more discouraging. Here we can explicit see that the grass is splintery along the stalk in up to a couple of inches distance. The whole part of the grass that has been splintered is wasted because it will obstruct new growth and make the plants loosing much humidity. The part that is destroyed will in addition only fade away and be reduced harvest that is lost. Then to the part we do not see directly on the picture but what if possible might bee even more seriously. You can not tear and pull in plants in this way without destroying parts of the fine plant root system. Maybe on weed such as couch grass but not on utility plants like timothy and other common hey plants. When you look at the color of the splintered plant stubble you immediately see that it has a withered color showing that the grass doesnít feel good.
The new growth will start later and the plants will grow slower. These factors gives you quite sure a 10-20% reduction in harvest. At the same time as the weed faster takes over and the field must be seed again. A perfect mower like we want to make must cut the grass in a clean cut in an even height without tearing the roots of the plants in pieces. And this has a larger significance than you may think. If you with todayís disc mower have an earning on your grass harvest on 20 %, you will already here have the possibility of getting twice the profit because none of the working expenses will increase.

Picture 1 Do we want to have it this way? A field with very varying stubble height where the stubble bear impression of that grass has been shuffled forward before cutting and where therefore to much of what should have been harvested is left behind. The reason for this is not that a bad amateur has been here. This field has been mowed by a contractor that run large areas every year so therefore may be it is the equipment that is not good enough.

Cutting and splintering of plants that already are cut

What happens with the plants after they have been cut with todayís disc mower? Now the loss should have been over, but no. The grass must pass over a large area filled with running knives that try to splinter the grass as efficient as possible and many of the from wall to wall thrown pieces will fall on the ground and thereby increase the part of the harvest that get lost. It is not quite accidental that the disc mowers have skirt that goes quite to the ground even if it presses the grass down so that the knives thereby hurt the grass extra efficient. Remove it and you will fast understand why it is there. A perfect mower must therefore be designed in such a way that it doesnít need skirt that will shuffle the grass by the front of the machine. The machine must separate the grass and the knives so that the knives are unable to cut the grass several times before it leaves the mower.

Picture 2 Close-up of the same stubble as in picture 1. Here you can clearly see the devastation of the disc mowers knives. The stalks is almost teared of and splintered lengthwise in stead of being cut straight of. The cut are visible but think of the treatment the fine root system has got in the severe jerk these plants have been through.

Collection of the grass

My father, who was a farmer his entire life, pointed often out that he didnít liked the existing tractor mowed hay turning equipment that you have to use to collect the hay because they teared off much of the blades that therefore got lost by falling on the ground. And as he pointed out; it is here the best hey quality is. Our new mower will therefore have transport band that collect the grass into strings that efficient can be picked up by the round baler without further treatment before it comes into the baler and thus is secured against further loss and that soil can be rubbed into the grass.

Width and placing of the mower

It is a bit strange to me that front mounted mowers with large cutting width on 20 Ė 25 ft. (7-8 m) with transport bands that collects all in one string under the tractor, has not taken over the market yet. The benefits with such a solution are plenty:

  1. It will be much better to drive. All of us that have experienced how much less tiring it is to drive a self propelling combine in comparison with a towed combine know that. It is like a dream to steer along the edge when the cutting take place in front of you and out on the side in front of you in stead of behind aside of you so that you the whole time must sit in a back bend twisted position. This can wear out the back on everybody because it will be long hours in the season.
  2. By placing the mower in front of the tractor the place in the back will be free so that you can bring with you the round baler in the same operation. Ordinary back mounted mowers is today as known 6-10 ft. (2-3 m). One drive with the new mower will then replace: 3 drive with mower, 2 drives with hay collector to collect the grass, 1 drive with round baler and 1 drive if you have baler without packer. 1 drive in stead of 7. Think what that will mean in reduced driving strain on the grass roots. And last but not least you will reduce the working time.
  3. You can organize the driving in the most appropriate way like what you do when driving a combine. You do not have to drive down grass when you drive round the field the first round. This is especially important if you have many or small fields or fields with open ditches or dikes. If you have steep fields it might be very favorable to do the driving on the field in a special manner in order to drive as safe and efficient as possible.
  4. Apropos steep fields. Few bases in the world feel more slippery than a tractor wheel on newly cut grass in a steep. Those of us who have experienced to get grass under the tractor wheel know that. With a front mounted, wide mower with transport band that collect the grass safely between the wheels the wheels will always have safe grip and the risk for sliding will be avoided.
  5. A mower mounted in the front will also give weight on the front wheels. They will therefore steer and draw well even with a huge round baler mounted behind. The front wheels will not dig loose grass roots even with driving along the steep. Use of steering brakes that also will contribute to hard strain on the roots can be avoided.
  6. Possibility for using twin wheels. An extra wide front mounted mower with collecting transport band makes it possible to use twin wheels without trampling the newly cut grass down into the soil. Under very soaked conditions and pressure weak soil this can be quite important in order not to destroy the grass roots and thus the new growth.
  7. The possibility to use very wide low pressure tires with special pattern for grass that damages the roots much less than ordinary tractor wheels. The crop increase. This because you can do much more with the same tractor and therefore divide the costs for the tires on much larger areas.
  8. It will also give the possibility to use twin wheels so that the tractor becomes more stabile and thus reduce the overturn danger.
  9. It is not necessary to drive so far out on the edge of the field and still collect the grass by means of the transport bands.
  10. It will be extra favorable for the grass if you do the grass packing immediately after cutting because then the CO2-forming and thus the preservation of the grass will be the very best. Fresh grass will when dark (and that we have when it is compressed in a large round ball) fast begin to use oxygen and produce CO2. If it then also is packed immediately the CO2 will give a perfect hermetic preservation of the entire grass ball.
  11. You will be less weather dependant. You can drive as long as possible. Even with long lasting bad weather everything that has been cut and packed preserved and nothing will be destroyed.
  12. The grass will be collected without the wheels running over it and therefore you avoid getting earth into the grass. Earth in the grass is harmful for the animals that have to eat the grass.
  13. You can utilize the entire capacity on the round baler because such a large cutting width can give optimal feeding of the baler without to large driving speed.
  14. The grass strings will of course always be optimum placed for the feeding into the baler because it has been cut in the very same driving. The only things you need are to follow the edge of the uncut grass.
  15. Minimum loss because everything is collected in a string that the baler can pick up immediately after it has been cut and before it has got he time to sink down into the stubble. Thus the loss will be next to nothing.
  16. 16. Automatic stubble high control. Simplifies the work to an extent that you will be much less exhausted and that is important because the days often will be long in the season. To get an optimal crop it is important that the mower leave behind a stubble high like the one you have set all the time. Even this will increase the total crop.

The solution must of course be shaped so that it satisfies the following demands:

  1. The mower must be easy to fold together in such a way that the transport width is small. You must of course be able to maneuver the equipage on narrow district- and harvest roads.
  2. The folding must be possible to be done from the driverís seat because the fields often are small and the hours long. In this way we can avoid crushing- or other strain injuries.
  3. In addition you can by folding the machine together and turn it down again from the driverís seat save a lot of time if you have to drive on many fields. You can in this way rationally harvest many small fields.
  4. You donít even have to change between different equipment and tractors. Many of the injuries in the farming business happen during changing of equipments.
  5. If you do rental driving you often get paid per made ball. Then it is important to be able to make many balls from many fields since your earnings are directly dependant of the number of balls.
  6. If you in addition have equipment that harvest maximum of the grass with minimum destruction of the plant roots you will be preferred among the customers buying rental driving because they to get more harvest with maximum quality.
  7. Our mower will be unique in weight. This new mower will weight only between 1/3 and 1/6 of todayís mowers if you compare with the same cutting width. This because the mower is quite new developed and strengthen calculated from the forces it will have to stand. Parts of the machine where it accidentally can be overloaded will be equipped with safety couplings in such a way that the design doesnít have to be more heavily dimensioned than necessary during normal duty. Since weight represents costly metal we can thus produce the mower at a more reasonable price.
  8. Lighter tractor. The weight of the tractor must be in a reasonable proportion to the equipment weight. The new mower with cutting width of approx 24feet (7.5m) will have a weight of 1700 lbs (770 kgs) versus todayís disc mowers at calculated to the same width will weight 6600-15400 lbs (3-7 metric tons). It is obvious that you can use a smaller and thus less costly tractor. Less soil pressure damages.
  9. Less power demand. Our new mower will need much less tractor power because the cutting knives will be shaped quite different so they cut the grass much more correct.
  10. The cutting edges will be delivered in hard metal. That is 10 times harder than the steel other manufacturers are using. Our knives will therefore keep its sharpness at least 100 times longer than the knives the others are using. This you can conclude from how long i.e. saw blade with hard metal tips keep its sharpness in comparison with ordinary steel saw blade. We can allow ourselves to use knives with hard metal edge because we use so considerably less steel in the other parts of the mower. (An apropos to this; A supplier of hard metal parts we contacted had little belief in that we should be able to enter the market delivering knives with hard metal edges to mowers until he heard that we would produce the entire machine our self. The reason for this mistrust to our possibility was that he had tried to offer hard metal knives for use in a machine for cutting wood where today only hardened steel knives are in use (like in disc mowers). He thought that hard metal from their experience with cutting wood fiber was the supreme best solution. The producer of the machine became furious by the suggestion because it would ruin his sale of spare knives. Maybe this is the reason hard metal knives is not taken for granted in disc mowers already long time ago.) The hard metal producer therefore got strong belief in our suggestion about using knives with hard metal edge since we also shall deliver the entire mower and therefore have decided not to use sale of knives and other spare parts as a substantial part in our earning policy.
  11. The engine power must also be sufficient even when the knives begin to be unsharp in the time before they must be replaced. By using hard metal the sharpness will be kept the entire time and we will avoid periods with dull knives.
  12. Besides I think that the propulsion system must be shaped much simpler to reduce the production costs and get reduced weight.
  13. Light that makes it safe and without problems to drive late in the evening also in the autumn when the twilight starts earlier than in the middle of the summer. Therefore we will, as the only supplier, equip our mower with due working head lights outermost on each side at the same way as on todayís combines.
  14. I have always liked to see what I do. Therefore I think that it is strange that the other manufacturers have made machines where you canít see what happens at the knives even if the reason is obvious that plant parts and plant sap will splash around. This tells me that the process must be wrong and suboptimal. I am of the opinion that the cover on a mower ought to be made of coarse-meshed netting that protect against contact but doesnít obstruct you from paying attention. Think if someone had introduced similarly covered cutting board on combines. My word, which would be a calamity.
  15. Why must the most disc mower look so badly inside? That is because the discs are built in and completely closed from sun light and wind that can dry up the insides from plant sap and dew and other humidity. Grass remaining and dirt fastens inside on the tight walls and skirts and make perfect growing conditions for an embers existing of rust, bacteria and microbes of many different kinds that stick to the surface and practically speaking never dries up through the season. That makes the machines a mare to maintain. This in addition to that you must buy and carry with you lots of extra steel weight and skirt material as if the disc mower doesnít weight enough beforehand. As a minimum at least the cover should have been made of coarse-meshed netting so that sun and wind could get inside and dried the machine as with the earlier sickle mowers. This will of coarse we do on the new mower.

Less working expenses and increased profit

How much you could earn extra by changing to a better mower you must evaluate yourself. But it will be a lot when you sum up the losses from all potential loss sources you have here. It is of course almost obvious that the work expenses will be strongly reduced when the need for tractor hours and power need will be strongly reduced. In addition the investment costs will also be reduced.

Reflections

It is with a little bit of concern that I continue to put agricultural equipment under the magnifying glass and expose how poor the existing machines are. When I started with the evaluation of the disc mower I was not prepared on finding so many weaknesses. We are from advertisements, brochures and commercials from the huge manufacturing companies all the time been told that the machines are almost perfect. Different agricultural magazines donít wish to take up this theme. I believe that they feel it little bit ticklish and that they feel afraid of loosing advertisement income. Someone has indeed interpreted this as a criticism of the farmers which it absolute not is, because they are of course given no choice but buying the machines they are offered by the manufacturers. When I still are continuing this examination it is because only by getting the problems up on the table that it is possible to do something with them. It also is of great importance that someone is very pleased with this carefully study. When I started working with the disc mower the first statement I got was that I should have started with this long time ago, because he felt that the work with disc mower mostly consisted of repair and maintenance. The most important with agricultural machines is that the farmers get the very best equipment for doing their job. I got the feeling, as I studied these machines, that the agricultural machine manufacturers have more focus on how they can realize for as much money as possible and focus less on how to develop more optimum equipment for the farmers. Maybe this is a development that is a result of that the machine manufacturers today are owned by investors and investment companies which are not primarily guided by how they can make optimum agricultural equipment but from how they can earn as much money as possible. How to get the very best results on the bottom line as it so pretty is named. Then they cannot afford expenses for analyzes and creative tries. Then it will be safest to copy others, but in the long run that will only result in stagnation and poor solutions. It is actually a bit unbelievable that we donít see new products faster when the existing have so many weaknesses but it maybe become this way when the different manufacturers have copied each other uncritically because they have expected that the first knows what he did without more closely analyzing.
If we shall be able to start building up production of these new mowers, we must build the production from the ground. This will happen if the interests, among farmers, for this type of mowers are so large that it pays off to start an efficient production. The longer it goes, the more it is you as farmer that will suffer by the fact that your crop is lower than necessary every year.
If you are interested or have views please contact us on email: mailto:flagro@fladby.com so we can map the interest. The more that are interested the faster we can start the production. Flagroís internet: http://flagro.fladby.com

© Tron-Halvard Fladby/ 2006.05.31