A tillage tool and use of a tillage tool

Abstract

Disclosed is a tillage tool (1) comprising, a main frame (2) arranged to be propelled over a ground surface (3) in a travel direction (4) and a boom (5) rotatably connected to the main frame (2), wherein a boom rotational axis (6) of the boom (5) is arranged askew in a boom angle (BOA) in relation to the travel direction (4). Furthermore, the tillage tool (1) includes two or more tool arms (7) each comprising a bracket (8) having a longitudinal bracket extent (BRE) with a first bracket end (9) and a second bracket end (10) arranged at opposite ends of the longitudinal bracket extent (BRE) of the bracket (8), and a ground engaging blade (11) having a longitudinal blade extent (BLE) with a first blade end (12) and a second blade end (13) arranged at opposite ends of the longitudinal blade extent (BLE) of the ground engaging blade (11). The two or more tool arms (7) are each connected to the boom (5) at the first bracket end (9) so that the second bracket end (10) is extending radially away from the boom (5), wherein the first blade end (12) of the ground engaging blade (11) is connected to the bracket (8) at the second bracket end (10) so that the second blade end (13) is extending further radially away from the boom (5) than the second bracket end (10), and wherein the longitudinal blade extent (BLE) is arranged askew in a blade angle (BLA) in relation to the longitudinal bracket extent (BRE) so that the longitudinal blade extent (BLE) is aligned with the travel direction (4) within a tolerance of plus / minus 15⁰, preferably within plus / minus 10⁰ when the bracket (8) is extending radially in the travel direction (4). Use of a tillage tool (1) is also disclosed.

Description

[0001] A TILLAGE TOOL AND USE OF A TILLAGE TOOL

[0002] Field of the invention

[0003] The invention relates to a tillage tool comprising a main frame arranged to be propelled over a ground surface in a travel direction and a boom including two or more tool arms, wherein the boom is rotatably connected to the main frame. The invention further relates to use of a tillage tool.

[0004] Background of the invention

[0005] Tillage tools - such as ploughs, cultivators, harrows and the like - are used in agriculture or botany for overturning, loosening and agitating soil, typically by dragging a blade-like object through the soil by use of a tractor. However, it requires much energy to pull a traditional plough blade or the tines of a harrow through the soil and in relation to traditional ploughs further disadvantages are that they typically only turn over the soil - which can lead to insufficient aeration and mixing of the soil - and the bottom of the plough blade can form a denser or more compacted layer in the ground through which it is difficult or impossible for crop roots to penetrate.

[0006] An alternative could therefore be to use disc harrows, disc ploughs or discers in that it requires less energy to pull these tools through the soil. However, forming these tools big enough for deeper primary tillage is difficult and costly, and the compacted soil left under the depth of disking can impact root growth. And a common problem with both tillage tools comprising blades being pulled through the soil and disc tools are that they create continuous ridges or furrows that can lead to washing and erosion.

[0007] Thus, from the patent US 3,107,737 it is known to provide a tillage implement comprising wheels consisting of a plurality of identical, elongated, longitudinally arcuate teeth circumferentially spaced around a cylindrical hub so that the wheels may rotate when pulled across the soil to make the teeth penetrate the soil surface so that each tooth overturn a part of the soil. However, this design is complex and costly. It is therefore an object of the present invention to provide for a cost-efficient tillage tool overcoming the above disadvantages.

[0008] The invention

[0009] The invention provides for a tillage tool comprising, a main frame arranged to be propelled over a ground surface in a travel direction and a boom rotatably connected to the main frame, wherein a boom rotational axis of the boom is arranged askew in a boom angle in relation to the travel direction. Furthermore, the tillage tool includes two or more tool arms each comprising a bracket having a longitudinal bracket extent with a first bracket end and a second bracket end arranged at opposite ends of the longitudinal bracket extent of the bracket, and a ground engaging blade having a longitudinal blade extent with a first blade end and a second blade end arranged at opposite ends of the longitudinal blade extent of the ground engaging blade. The two or more tool arms are each connected to the boom at the first bracket end so that the second bracket end is extending radially away from the boom, wherein the first blade end of the ground engaging blade is connected to the bracket at the second bracket end so that the second blade end is extending further radially away from the boom than the second bracket end, and wherein the longitudinal blade extent is arranged askew in a blade angle in relation to the longitudinal bracket extent so that the longitudinal blade extent is aligned with the travel direction within a tolerance of plus / minus 15°, preferably within plus / minus 10° when the bracket is extending radially in the travel direction.

[0010] Tillage, and especially primary tillage, can induce much strain on the tool arms and it is therefore advantageous that the tool arms are connected to the boom so that the tool arms can easily be changed if damaged - e.g. by rocks in the soil, fatigue failure or other. And likewise, the ground engaging blade will be strained and worn when cutting through and digging up the soil causing the blade to be a wear part. It is therefore advantageous that the blade is connected to the bracket so that the blade may easily be changed when worn out without having to change the entire tool arm. Furthermore, making the tool arms comprise both a bracket and a blade is advantageous in that it hereby is possible to form the bracket from a more flexible material such as some kind of spring steel making the it less likely that the tool arm is damaged if the tool arm engages stones, rocks or the like during use, while at the same time enabling that the blade can be made from another material more durable in relation to the constant wear when being pushed through the soil.

[0011] Furthermore, arranging the boom askew in a boom angle in relation to the travel direction and arranging the longitudinal blade extent of the ground engaging blade askew in a blade angle in relation to the longitudinal bracket extent so that the longitudinal blade extent is aligned with the travel direction within a tolerance of plus / minus 15°, preferably within plus / minus 10° when the bracket is extending radially in the travel direction - i.e. when the bracket is substantially horizontal and pointing forward in the direction of travel - is advantageous in that the blade hereby will engage the surface of the soil and subsequently perform a both longitudinal and transversal motion through the soil that will prevent formation of furrows, it will ensure aeration and mixing of the soil while at the same time reducing the energy needed to pull the tillage tool, in that the carving motion of the blade through the soil generates less resistance than traditional tillage tools. Accordingly, it is possible to form the tillage tool wider that traditional tillage tools or use less energy (e.g., a smaller tractor) to tillage the same width. And the carving motion of the blade also enables that the blades can be formed so long that the tillage tool can be used for primary tillage - i.e. tillage down to a depth of 15-45 cm depending to soil type, crops and other.

[0012] In this context, the term “main frame” should be understood as a beam construction, a lattice construction, a frame or other kind of stiff structure which may carry the boom and e.g. additional equipment. In this context, the term “ground engaging blade” should be understood as a tooth, hoe, shovel, plough, tyne or any other kind of object which may be used for agitating the ground.

[0013] In an aspect of the invention, the ground engaging blade comprises a curvature so that the second blade end of the ground engaging blade is bent downwards when the bracket is extending radially in the travel direction.

[0014] Providing the ground engaging blade with a downwards arcing curvature as seen when the bracket is extending radially forward in the travel direction during normal use of the tillage tool is advantageous in that the blade hereby penetrates the soil more “cleanly”, meaning that the tip of the blade hereby initially penetrates the soil and the curvature ensures that more of the rest of the blade continues into the hole formed by the tip (because the blade tillage tool is also traveling forward during use) thereby reducing the force needed for the entire blade to penetrate the soil and local compression of soil is reduced.

[0015] In an aspect of the invention, a radially outer part of the ground engaging blade is provided with a bend having a blade radius of between 25% and 95%, preferably between 35% and 85%, and most preferred between 45% and 75% of a blade tip radius of the ground engaging blade to form the curvature, wherein the blade tip radius is the distance between the boom rotational axis and a radially outermost tip of the ground engaging blade.

[0016] If the blade radius of the blade is too little in relation to the blade tip radius, the tip of the blade will attack the soil surface in an angle pointing away from the travel direction and the upper side of the blade will press against the soil during the blades travel through the soil making it more difficult for the blade to penetrate the soil and more difficult to control the correct operation depth of the blade in the soil. Furthermore, this will also lead to local soil compression and excess force needed to operate the tillage tool at a correct soil depth. However, if the blade radius of the blade is too big in relation to the blade tip radius, the tip of the blade will attack the soil surface in an angle pointing in the travel direction and the lower side of the blade will press against the soil during the blades travel through the soil also making it more difficult for the blade to penetrate the soil and making it more difficult to control the correct operation depth of the blade in the soil. Furthermore, this will also lead to local soil compression and excess force needed to operate the tillage tool at a correct soil depth. Accordingly, the present relationship ranges between blade radius and blade tip radius are advantageous in relation to operation of the tillage tool and subsequent quality of the processed soil.

[0017] In an aspect of the invention, the bracket is extending radially in a forward rotational direction as seen when the main frame is propelled in the travel direction during normal use of the tillage tool.

[0018] Making the bracket extend radially in a forward rotational direction - i.e. forward in relation to a radius extending from the boom rotational axis to the root of the bracket at the outer surface of the boom as seen in the direction of the boom rotational axis - is advantageous in that this makes it easier for the blade to penetrate and travel through the soil without locally compressing the soil.

[0019] In an aspect of the invention, the bracket is extending radially in the forward rotational direction in a bracket angle of between 4° and 65°, preferably between 6° and 55°, and most preferred between 8° and 45°, wherein the bracket angle is measured between the longitudinal bracket extent of the bracket and a root radius extending between the boom rotational axis and a root of the bracket’s longitudinal bracket extent at the first bracket end.

[0020] If the bracket angle is too little or too big it is difficult to form and arranged the blade so it does not attack the soil surface in skew angle pointing which will cause the upper or the lower side of the blade to press against the soil during the blades travel through the soil making it more difficult to control the correct operation depth of the blade in the soil, which also can lead to local soil compression and excess force needed to operate the tillage tool at a correct soil depth. Accordingly, the present bracket angle ranges are advantageous in relation to operation of the tillage tool and subsequent quality of the processed soil.

[0021] In an aspect of the invention, the two or more tool arms are angularly evenly distributed around the boom.

[0022] Providing the boom with more than one tool arm angularly evenly distributed around the boom is advantageous in that more tool arms will cause more interaction with the soil per boom rotation and thereby lead to a more efficient tillage tool. And distributing the tool arms angularly evenly around the boom will ensure a more even and controlled soil interaction.

[0023] In an aspect of the invention, the tillage tool includes three or more tool arms which are angularly evenly distributed around the boom.

[0024] Providing the boom with at least three tool arms angularly evenly distributed around the boom is advantageous in that this ensures that at least one tool arm is engaging the soil at all times when the tillage tool is propelled across the soil surface, which will ensure that the soil engaging tool arm will drive the rotation of the boom at all times during normal use of the tillage tool.

[0025] In an aspect of the invention, the two or more tool arms are mutually angularly displaced around the boom and arranged at the same axial position on the boom to form a tool arm circle.

[0026] Arranging several mutually angularly displaced tool arms around the boom at the same axial position on the boom is advantageous in that the tool arms hereby easier can drive the rotation of the boom when the tillage tool is dragged across the soil surface and because this ensures better tillage of the soil.

[0027] In an aspect of the invention, the tool arm circle comprises between two or fourteen, preferably between four and twelve, and most preferred between six and ten tool arms.

[0028] If the tool arm circle comprises too few tool arms the tillage tool becomes too inefficient and if the tool arm circle comprises too many tool arms the tillage tool becomes too expensive - in relation to efficiency - and the risk of unwanted buildup of material between the tool arms increases due to the smaller gap between the tool arms. Furthermore, if the tool arm circle comprises too many tool arms it becomes too difficult to get the individual blades to penetrate the ground correctly because the tool arm circle starts functioning as a wheel. Accordingly, the present ranges are advantageous in relation to efficiency and cost.

[0029] In an aspect of the invention, the boom comprises at least two tool arm circles wherein the at least two tool arm circles are axially displaced in relation to each other on the boom.

[0030] Providing the boom with two or more axially displaced tool arm circles is advantageous in it hereby is possible to tillage a wider part of the field in one go.

[0031] In an aspect of the invention, the boom angle is between 25° and 85°, preferably between 35° and 80°, and most preferred between 45° and 75°, wherein the boom angle is the smallest angle measured between the travel direction and the boom rotational axis.

[0032] If the boom angle is too big, the transversal movement of the blade during its travel though the soil is reduced and the risk of generating significant furrows is increased. However, if the boom angle is too little the main frame becomes unnecessarily big and the tillage efficiently of the tool arms are reduced. Thus, the present boom angle ranges are advantageous in relation to efficiency and cost.

[0033] In an aspect of the invention, the tillage tool comprises a further boom rotatably connected to the main frame, wherein the further boom comprises two or more further tool arms, wherein a further boom rotational axis of the further boom is arranged askew in a further boom angle, wherein the further boom angle is a mirror of the boom angle around a plane perpendicular to the travel direction.

[0034] The transversal movement of the blade during its travel though the soil will push the boom in a direction transversal to the travel direction. However, by providing the tillage tool with a further boom arranged in a further boom angle which is a mirror of the boom angle around a plane perpendicular to the travel direction the transversal pull of the two booms will counteract each other.

[0035] In an aspect of the invention, the further tool arms are mutually angularly displaced around the further boom and arranged at the same axial position on the boom to form a further boom tool arm circle and wherein the further boom tool arm circle is displaced from a tool arm circle of the boom as seen in the travel direction.

[0036] Displacing the further boom tool arm circle axially from a tool arm circle of the first boom, so that the further boom tool arm circle is displaced from a tool arm circle of the first boom as seen in the travel direction, is advantageous, in that more soil is hereby processed in the same go whereby the tillage tool becomes more effective.

[0037] In an aspect of the invention, the first blade end of the ground engaging blade is connected to the bracket at the second bracket end by means of releasable mechanical connection means. Connecting the ground engaging blade to the bracket by means of releasable mechanical connection means is advantageous in that this enables fast and easy exchange of blades if they are worm out or damaged.

[0038] In this context the term “connection means” should be understood as any kind of connector suitable for releasably connecting the ground engaging blade to the bracket. I.e., the term includes any kind of screws, bolt, wedging mechanism, interlocking geometry, clamping mechanism or other or any combination thereof.

[0039] In an aspect of the invention, at least a radially outer part of the ground engaging blade tapers off towards the second blade end.

[0040] Making the blade taper off so that the free end is pointy is advantageous in that the blade hereby may penetrate the soil surface more easily while the body of the blade gets wider and thereby stronger the further into the soil the blade is digging thereby reducing the risk of the blade bending or braking while at the same time ensuring smooth travel through the soil.

[0041] In an aspect of the invention, the boom is connected to the main frame so that the boom rotational axis is substantially parallel with the ground surface during normal use of the tillage tool.

[0042] Arranging the boom so that it is substantially parallel with the ground surface during normal use of the tillage tool is advantageous in that all the tool arms hereby can be formed identical to ensure a uniform tillage.

[0043] In an aspect of the invention, the main frame comprises vehicle connections means arranged for connecting the tillage tool to a motor vehicle to propel the main frame over the ground surface in the travel direction. Providing the main frame with vehicle connections means is advantageous in that the tillage tool hereby easily can be connected to a motor vehicle - such as a tractor - so that the tillage tool may be pulled across the ground to till the soil.

[0044] In an aspect of the invention, the longitudinal blade extent is arranged askew in the blade angle in relation to the longitudinal bracket extent in that a blade centreline extending along the middle of the longitudinal blade extent of the ground engaging blade is arranged askew in the blade angle in relation to a bracket centreline extending along the middle of the longitudinal bracket extent of the bracket. Hereby is achieved an advantageous embodiment of the invention.

[0045] In an aspect of the invention, the blade angle between the longitudinal blade extent and the longitudinal bracket extent is between 10° and 70°, preferably between 17° and

[0046] 60°, and most preferred between 25° and 50°, wherein the blade angle is measured between the longitudinal blade extent and the longitudinal bracket extent on the side radially furthest away from the boom rotational axis.

[0047] If the blade angle is too big it becomes too difficult to perform primary tillage in that the blade and / or the bracket must be longer and thereby more vulnerable. However, if the blade angle is too little it becomes too difficult to penetrate the soil correctly and ensure a smooth travel of the blade through the soil. Thus, the present blade angle ranges are advantageous in relation to durability and function.

[0048] In an aspect of the invention, the bracket and / or the ground engaging blade comprise fixation means enabling that the longitudinal blade extent of the blade can be arranged askew in the blade angle in relation to the longitudinal bracket extent on both sides of the longitudinal bracket extent.

[0049] Making the bracket and / or the ground engaging blade comprise fixation means designed so that the blade can be arranged askew in relation to the longitudinal bracket extent to both sides is advantageous in that the same brackets and blades hereby can be used on booms being askew in both directions thereby simplifying logistic, manufacturing and reducing costs.

[0050] In this context the term “fixation means” should be understood as any kind of fixator suitable for connecting a ground engaging blade to a bracket. I.e., the term includes any kind of screws, bolt, wedging mechanism, threaded holes, interlocking geometry, clamping mechanism or other or any combination thereof.

[0051] In an aspect of the invention, an outer boom radius of the boom is between 5% and 80%, preferably between 10% and 60%, and most preferred between 15% and 40% of a bracket tip radius of the bracket, wherein the bracket tip radius is the distance between the boom rotational axis and an radially outermost tip of the bracket and wherein the outer boom radius is the distance between the boom rotational axis and a radially outermost extent of the boom at which the first bracket end of the bracket is connected to the boom.

[0052] If the outer boom radius is too little in relation to the bracket tip radius it becomes too difficult or impossible to fit enough tool arms around the boom at the same axial location and the tillage tool thereby becomes less efficient. Furthermore, a relatively small outer boom radius means that the tool arms will have to be longer which in turn means that particularly the brackets will have to be bigger and stronger to ensure sufficient strength - thereby increasing cost. However, if the outer boom radius is too big in relation to the bracket tip radius it is difficult to form the bracket so that they have the necessary flexibility so that they do not break or bend when the blade meets excess resistance - e.g., in the form or rocks, particularly compact soil or other. Furthermore, if the bracket becomes too short the risk of material build-up between the brackets will increase in that material will more easily be compacted between the brackets due to the short distance between the soil surface and the radially outermost extent of the boom. Thus, the present relationships between outer boom radius and bracket tip radius are advantageous in relation to efficiency and functionality. In an aspect of the invention, a blade width of the blade at a part of the ground engaging blade extending further radially away from the boom than the second bracket end is between 10% and 85%, preferably between 20% and 78%, and most preferred between 35% and 70% of a bracket width of the bracket, wherein the blade width is the width of the ground engaging blade as measured in a direction transversal to the longitudinal blade extent and wherein the bracket width is the width of the bracket as measured in a direction transversal to the longitudinal bracket extent.

[0053] The blade is intended to be the wear part but if the blade is too wide in relation to the bracket the risk of the bracket breaking or bending if unexpected resistance is met is too high. Furthermore, if the width difference between the blade and the bracket is too little it becomes too difficult to control correct operational dept of the tillage tool because some of the bracket could also dig into the ground. However, if the blade is too narrow in relation to the bracket the bracket becomes unnecessarily wide and costly. Thus, the present width relation ranges present an advantageous relationship between function and cost.

[0054] In an aspect of the invention, a bracket tip radius of the bracket is between 15% and 90%, preferably between 25% and 75%, and most preferred between 35% and 65% of a blade tip radius of the ground engaging blade, wherein the bracket tip radius is the distance between the boom rotational axis and an radially outermost tip of the bracket and wherein the blade tip radius is the distance between the boom rotational axis and a radially outermost tip of the ground engaging blade.

[0055] If the bracket tip radius is too little in relation to the blade tip radius it becomes too difficult to design the bracket so that it provides the necessary flexibility if unexpected resistance is met. Furthermore, if the bracket is too short the risk of material build-up between the brackets will increase in that material will more easily be compacted between the brackets. However, if the bracket tip radius is too big in relation to the blade tip radius the brackets become unnecessarily long and expensive, and it becomes more difficult or impossible to fit enough tool arms around the boom at the same axial location of the tillage tool in relation to the length of the blade and the tillage tool thereby becomes less efficient. Thus, the present relationships between bracket tip radius and blade tip radius are advantageous in relation to cost, efficiency and functionality.

[0056] The invention further relates to use of a tillage tool according to any of the preceding claims for ploughing soil.

[0057] When ploughing, the soil should be overturned down to a depth of between 10-35 cm, typically around 13-23 cm, depending on the specific soil, the crops to be planted, subsequent soil treatment, and other, and since the tillage tool according to the present invention requires much less pulling force to overturn soil from this dept, the present tillage tool is particularly advantageous for overturning soil from this depth due to the smooth penetration of the soil and the blades motion through the soil.

[0058] Figures

[0059] The invention will be described in the following with reference to the figures in which. fig. 1 illustrates a tillage tool, as seen from the top, fig. 2 illustrates a cross section of a boom, as seen from the side, fig. 3 illustrates a bracket, as seen from the back, fig. 4 illustrates a cross section through a bracket, as seen from the side, fig. 5 illustrates a ground engaging blade, as seen from the side, and fig. 6 illustrates a ground engaging blade, as seen from the front.

[0060] Detailed description

[0061] Fig. 1 illustrates a tillage tool 1, as seen from the top.

[0062] In this embodiment the tillage tool comprises a main frame 2 forming the support structure for the entire tillage tool. In this embodiment the main frame 2 is a welded steel structure but in another embodiment the main frame could also or instead be formed by several subparts assembled by means of screws, bolts, rivets or other connection means and / or the main frame 2 could also or instead be made from aluminium, stainless steel or another metal and / or the main frame 2 could also or instead be made from another material such as plastic, a fiberglass reinforce composite material, wood or other.

[0063] In this embodiment the main frame 2 is provided with vehicle connections means 20 in the form of connection arms so that the tillage tool may be connected to a motor vehicle 21 - in this case a tractor - so that the main frame 2 may be propelled over the ground surface in in a travel direction 4. However, in another embodiment the vehicle connections means 20 could be formed in a multitude of other ways known to the skilled person depending on the specific motor vehicle, the specific tillage tool design, the specific task or other. Or in another embodiment the tillage tool 1 could be provided with its own drive system so that the tillage tool 1 would be self-propelled.

[0064] In this embodiment the tillage tool 1 is provided with a boom 5 - which in the following will be referred to as the first boom 5 - and a further boom 16 - which in the following will be referred to as the second boom 16 - arranged behind the first boom 5. However, in another embodiment the tillage tool 1 would only be provided with a single boom 5 or the tillage tool 1 could be provided with more than two booms 5, 16 - such as three, four, five, eight or even more booms 5, 16 - arranged at least partly in continuation of each other in the travel direction 4 and / or arranged at least partly side by side.

[0065] In this embodiment the booms 5, 16 are rotatably connected to the main frame 2 by means of bearings 23 arranged at either ends of the booms 5, 16 to ensure easy rotation of the booms 5, 16. However, in another embodiment the booms 5, 16 could be suspended by more or less bearings 23 or the rotational connection could be ensured without bearing simply by supporting the booms 5, 16 in a slightly oversized hole in the main frame 2 or other. In this embodiment the bearings 23 are standard spherical roller bearings but in another embodiment the bearings could be ball bearing, roller bearing, needle bearings, plain bearing or other or any combination thereof.

[0066] In this embodiment the boom rotational axis 6 of the first boom 5 is arranged askew in a boom angle BOA of 60° in relation to the travel direction 4 - as seen from above during normal use of the tillage tool 1 - and a further boom rotational axis 24 of the second boom 16 is arranged askew in a further boom angle FBA being a mirror of the first boom angle BOA around a plane perpendicular to the travel direction 4 - as seen from above during normal use of the tillage tool 1 and measured on the same side in relation to the travel direction as the boom angle BOA. I.e., in this embodiment the further boom angle FBA is 120° - so that the internal angle between the boom rotational axis 6 the further boom rotational axis 24 is 60° - but in another embodiment the boom angle BOA could be smaller - such as 54°, 47°, 40°, or even smaller - and the corresponding further boom angle FBA would then be 126°, 133°, 140°, or even bigger. Or in another embodiment the boom angle BOA could be bigger - such as 68°, 76°, 83°, or even bigger - and the corresponding further boom angle FBA would then be 112°, 104°, 97°, or even smaller. However, in another embodiment further boom angle FBA would not be an exact mirror of the first boom angle BOA - i.e., in another embodiment the boom angle BOA and the further boom angle FBA could be offset from a mirror of each other by e.g. plus / minus 5-20 degrees. For example, the boom angle BOA could be 65° and the further boom angle FBA be 105° degrees e.g., to reduce the risk of furrow formation or to better till the soil.

[0067] In this embodiment, two tool arms 7 are mutually angularly displaced around the first boom 5 at different axial locations to form axially evenly displaced tool arm circles 15 - called first tool arm circles 15 in the following - and two tool arms 7 are mutually angularly displaced around the second boom 16 at different axial locations to form axially evenly displaced further boom tool arm circles 18 - called second tool arm circles 18 in the following. In this embodiment both the first boom 5 and the second boom 16 are shown with only two tool arms 7 in each tool arm circles 15, 18 to simplify the illustration but in a preferred embodiment each tool arm circles 15, 18 would comprise more tool arms 7 in each tool arm circles 15, 18 as will be discussed in detail in relation to fig. 2. In this embodiment each of the booms 5, 16 comprises twelve tool arm circles 15, 18 giving the tillage tool 1 an effective width of around 4.5 meters which is easily drawn by a normal sized modem tractor 21. However, in another embodiment each boom 5, 16 could comprise more tool arm circles 15, 18 - such as 15, 18, 24 or even more -, or each boom 5, 16 could comprise less tool arm circles 15, 18 - such as 10, 8, 4 or even down to one tool arm circle 15, 18 -, e.g., depending on the specific use, available motor vehicle 21, the specific soil or other.

[0068] In this embodiment, all the second tool arm circles 18 of the second boom 16 are displaced from all the first tool arm circles 15 of the first boom 5 - as seen in the travel direction 4 - so that the tillage tool 1 will process the soil more efficiently over the entire width of the tillage tool 1. However, in another embodiment some or all of the second tool arm circles 18 could be aligned with the first tool arm circles 15 e.g., to process the soil better. In this embodiment all the tool arms 7 on the first boom 5 are more or less identical and all the tool arms 7 on the second boom 16 are also more or less identical. However, in another embodiment the tool arm design on each boom 5, 16 could vary - e.g., depending on the specific use or other. In this embodiment each tool arm 7 comprises a bracket 8 having a longitudinal bracket extent BRE between a first bracket end 9 and a second bracket end 10, and a ground engaging blade 11 having a longitudinal blade extent BLE between a first blade end 12 and a second blade end 13. In this embodiment the tool arms 7 are connected to boom 5 at the first bracket end 9 and the first blade end 12 of the blade 11 is connected to the bracket 8 at the second bracket end 10 so that the second blade end 13 is extending further radially away from the booms 5, 16 than the second bracket end 10. In this embodiment fig. 1 is disclosing the tool arms 7 on the front side of the booms 5, 16 in a position where the brackets 8 are extending radially in the travel direction and the tool arms 7 on the back side of the booms 5, 16 in a position where the brackets 8 are extending radially away from the travel direction. I.e., in fig. 1 all the brackets 8 are extending in a horizontal direction parallel with the underlying ground surface. It should be noted that the expression “the bracket 8 is extending radially in the travel direction 4” is not in any way limited to the longitudinal bracket extent BRE of the bracket being parallel with the travel direction 4. This expression also covers that the longitudinal bracket extent BRE is extending in the general direction of the travel direction 4 as long as the longitudinal bracket extent BRE is horizontal and parallel with the underlying ground.

[0069] In this embodiment the longitudinal blade extent BLE of the blades 11 is arranged askew in a blade angle BLA in relation to the longitudinal bracket extent BRE in that a blade centreline extending along the middle of the longitudinal blade extent BLE of the ground engaging blade 11 is arranged askew in the blade angle BLA in relation to a bracket centreline extending along the middle of the longitudinal bracket extent BRE of the bracket 8. In this embodiment the longitudinal blade extent BLE is arranged askew in a blade angle BLA of around 37° in relation to the longitudinal bracket extent

[0070] BRE - measured on the side radially furthest away from the boom rotational axis 6. However, in another embodiment the blade angle BLA could be bigger - such as 40°, 45°, 55° or even bigger - or the blade angle BLA could be smaller - such as 34°, 30°, 24° or even smaller - e.g., depending on the boom angle BOA and / or the further boom angle FBA, the specific use or other. Thus, in this embodiment the longitudinal blade extent BLE is offset 7° in relation to the travel direction 4 (because the boom rotational axis 6 of the booms 5, 16 are arranged askew in a boom angle BOA of 60° and 120° in relation to the travel direction 4. However, in another embodiment the longitudinal blade extent BLE could be parallel with the travel direction 4, the longitudinal blade extent BLE could be offset more in relation to the travel direction 4 - such 9°, 11°, 13° or even more to both sides -, or the longitudinal blade extent BLE could be offset less in relation to the travel direction 4 - such 6°, 4°, 2° or even less to both sides - depending on the specific blade design, the specific use or other.

[0071] As explained in relation to figs. 3-6 the blades 11 and the brackets 8 can be designed in a multitude of ways but to ensure that the tool arms meets extra resistance when the bracket 8 reaches the soil surface - to control the processing dept better - it is advantageous that the bracket 8 is wider than the blade 11 so that substantially only the part of the blade 11 extending radially further from the boom 5 than the second bracket end 10 is digging into the soil. Thus, in this embodiment the blade width BLW of the ground engaging blade 11 radially just above the second bracket end 10 is around 75 mm and the bracket width BRW of the bracket 8 is around 150 mm. Thus, in this embodiment the part of the ground engaging blade 11 just extending further radially away from the boom 5 than the second bracket end 10 is 50% of the bracket width BRW of the bracket 8. However, in another embodiment the transversal width BLW of the blade 11 could be wider - such as 58%, 64%, 72% or even more of the transversal width BRW of the bracket 8 -, or the transversal width BLW of the blade 11 could be narrower - such as 46%, 42%, 33% or even less of the transversal width BRW of the bracket 8.

[0072] Fig. 2 a cross section of a boom 5, as seen from the side.

[0073] In this embodiment the boom 5 is provided with eight tool arms 7 angularly evenly distributed around the boom 5 to form a tool arm circle 15. However, in another embodiment at least some of the tool arms 7 would not be angularly evenly distributed around the boom 5. In another embodiment the tool arm circle 15 would comprise more tool arms 7 - such as nine, thirteen, fifteen or even more - or the tool arm circle 15 would comprise less tool arms 7 - such as seven, five, three or even less -, e.g., depending on the specific use, the design of the tool arms 7 or other. In an embodiment each tool arm circle 15 could comprise as little as one tool arm 7 each if e.g. the boom 5 comprised several tool arm circles 15 and the tool arms 7 was angularly displaced to form a helix around the boom 5.

[0074] In this embodiment the ground engaging blade 11 is provided with a curvature so that the second blade end 13 of the ground engaging blade 11 is bent downwards when the bracket 8 is extending radially in the travel direction 4 as the blade 11 indicated by the numerical “11” in fig. 2. In this embodiment the curvature is a simple circular arc but in another embodiment the curvature could be a part of a parabola, a part of a hyperbola or another complex curvature or any combination thereof. In this embodiment the entire radially outer part 14 of the ground engaging blade 11 - i.e., the part of the blade extending radially further from the boom 5 than the second bracket end 10 of the bracket 8 - is provided with a bend having a blade radius BLR of around 59% of the blade tip radius BLTR - i.e., the distance between the boom rotational axis 6 and the radially outermost tip of the ground engaging blade 11 - in that in this embodiment the blade tip radius BLTR is around 51 cm and the blade radius BLR is around 30 cm. However, in another embodiment the blade radius BLR could be bigger in relation to the blade tip radius BLTR - such as 66%, 71%, 79% of the blade tip radius BLTR or even bigger - or the blade radius BLR could be smaller in relation to the blade tip radius BLTR - such as 55%, 49%, 41% of the blade tip radius BLTR or even smaller -, e.g., depending on the specific use, the specific blade design, the specific tool arm design or other.

[0075] In this embodiment the brackets 8 are extending radially in a forward rotational direction in a bracket angle BRA of 20° measured between the longitudinal bracket extent BRE of the bracket 8 and a root radius RR extending between the boom rotational axis 6 and a root of the bracket’s longitudinal bracket extent BRE at the first bracket end 9. However, in another embodiment the bracket angle BRA could be smaller - such as 10°, 0°, -10° or even smaller - or the bracket angle BRA could be bigger - such as 30°, 40°, 50° or even bigger -, e.g., depending on the blade design, the specific use or other.

[0076] In this embodiment the first blade end 12 of the ground engaging blade 11 is connected to the bracket 8 at the second bracket end 10 by means of releasable mechanical connection means 19 - in this case in the form of bolts extending through through- going holes in the blade 11 and the bracket 8 and secured by means of a nut. However, in another embodiment the blade 11 could also or instead be connected to the bracket 8 by means of a snap-lock system, by interlocking geometry by means of welding or other.

[0077] In this embodiment the outer boom radius OBR of the boom 5 is around 7.5 cm and bracket tip radius BRR of the bracket 8 is around 30 cm so in this embodiment the outer boom radius OBR is around 25% of the bracket tip radius BRR. However, in another embodiment the boom radius OBR could be smaller and / or the bracket tip radius BRR could be bigger so that the boom radius OBR would only be 22%, 17%, 13% of the bracket tip radius BRR or even less, or the boom radius OBR could be bigger and / or the bracket tip radius BRR could be smaller so that the boom radius OBR would be 28%, 35%, 43% of the bracket tip radius BRR or even more - e.g., depending on the specific use, the specific bracket design or other. It could e.g., be advantageous to increase the outer boom radius OBR to form shorter brackets 8 to reduce the cost of the brackets 8 but if the brackets become too short it becomes difficult to form the brackets both sufficiently strong and flexible that they will flex without breaking or bending when the blade meets unexpected resistance during its travel through the soil.

[0078] In this embodiment the blade tip radius BLTR is around 51 cm and the bracket tip radius BRR is around 30 cm so in this embodiment the bracket tip radius BRR of the bracket 8 is around 59% of the blade tip radius BLTR of the ground engaging blade 11. However, in another embodiment the blade tip radius BLTR could be smaller and / or the bracket tip radius BRR could be bigger so that the bracket tip radius BRR would only be 51%, 45%, 33% of the blade tip radius BLTR or even less, or the blade tip radius BLTR could be bigger and / or the bracket tip radius BRR could be smaller so that the bracket tip radius BRR would be 61%, 68%, 77% of the blade tip radius BLTR or even more - e.g., depending on the specific use, the specific bracket design, the specific blade design or other.

[0079] When the tillage tool is placed on the soil and pulled forward in the travel direction 4, the tip 14 of the blades 11 will be pressed into the soil by the gravitational pull in the tillage tool and given the circular motion of the tool arms 7 and the translational motion from the forward travel, the blade 11 will dig into the soil and once it passes the boom rotational axis 6 it will create a downwards force that will force subsequent blades into the soil. Once the blades 11 are digging so deep that the bracket 8 is starting to touch the soil when the tool arm 7 is facing vertically downwards, the resistance increases due to the wider and straight bracket 8 and the tool arms will - due to this resistance - dig no deeper. However, in another embodiment the tillage tool 1 could be provided with wheels or runners controlling the processing depth of the blades 11 or the motor vehicle 21 pulling the tillage tool 1 could comprise means for controlling the tillage tools height over the soil. Thus, in this embodiment the tillage tool 1 is used for primary tillage in the form of ploughing in that the blades 11 will dig around 24 cm into the soil as illustrated by the difference between the rolling circumference radius RCR - which in this case is around 27 cm - and the blade tip radius BLTR - which in this case is around 51 cm. However, in another embodiment the blades 11, the brackets 8 or other could be designed differently so that the effective processing dept of the tillage tool 1 in the soil would be bigger - such as 27 cm, 31 cm, 38 cm or even deeper (also called deep ploughing or grubbing) - or the effective processing depth of the tillage tool 1 in the soil would be smaller - such as 18 cm, 13 cm, 8 cm or even less (also called harrowing, cultivating or other)

[0080] Fig. 3 a bracket 8, as seen from the back and fig. 4 illustrates a cross section through a bracket 8, as seen from the side.

[0081] In this embodiment the bracket 8 comprise fixation means 22 in the form of through going holes enabling that the ground engaging blade 11 can be securely and releasably connected to the bracket 8 by means of bolts and nut. However, in another embodiment the through going holes could comprise thread so that the blades 11 could be connected by means of bolts or screws. In this embodiment the bracket 8 comprises four fixation means 22 arranged symmetrically around the longitudinal middle of the bracket 8 even though the blade 11 only comprises two through going holes. I.e., in this embodiment the blade 11 can be connected to the bracket 8 so that the longitudinal blade extent BLE of the ground engaging blade 11 can be arranged askew in the blade angle BLA in relation to the longitudinal bracket extent BRE on both sides of the longitudinal bracket extent BRE. I.e., in this embodiment the same bracket 8 can be used on the first boom 5 and the second boom 16. However, in another embodiment the bracket 8 - and / or the blade 11 - could comprise more holes or other kinds of connect! on / fixati on means 19, 22 - e.g., to connect the blade 8 in different blade angles BLA on both sides of the longitudinal bracket extent BRE - or the bracket 8 would only comprise fixation means 22 for connecting the blade in a single blade angle BLA on only one side of the longitudinal bracket extent BRE.

[0082] In this embodiment the first bracket end 9 comprises connection holes 25 enabling that the bracket 8 can be connected to the boom 5, 16 by means of bolts extending through corresponding holes in the boom 5, 16 and secured by means of nuts. However, in another embodiment the bracket 8 could be connected to the boom 5, 16 by means of bolts or screws engaging corresponding threaded holes in the boom 5, 16, by means of interlocking geometry - e.g., dove tail grooves -, some sort of snap lock mechanism, welding or other.

[0083] In this embodiment the bracket 8 is made from spring steel which is a term generally used in relation to a wide range of steels and the term spring steel is known to the skilled person - often known as carbon spring steel. These steels are generally low- alloy manganese, medium-carbon steel or high-carbon steel with a very high yield strength. However, in another embodiment the bracket 8 could also or instead be made from another metal - such as stainless steel, aluminium, titanium or other - and / or the bracket 8 could also or instead be made from a composite material - e.g. fibre reinforced, plastic, rubber or any combination thereof.

[0084] Except for the part of the bracket 8 being in contact with the boom 5 the bracket 8 is in this embodiment straight. However, in another embodiment this part of the bracket 8 could be formed with a curvature, a bend or other e.g., depending on the specific use, the specific connection method with the blade 11 or the boom 5, the specific blade or boom design or other.

[0085] Fig. 5 illustrates a ground engaging blade 11, as seen from the side, and fig. 6 illustrates a ground engaging blade 11, as seen from the front.

[0086] In this embodiment the longitudinal width of ground engaging blade 11 decreases all the way from the first blade end 12 to the second blade end 13 in that the blade tapers off all the way towards the second blade end 13. However, in another embodiment only the radially outer part 14 of the ground engaging blade 11 extending radially further away from the bracket 8 than the second bracket end 10 - i.e., the free protruding part of the blade 11 - would taper off towards the second blade end 13 or only an even smaller part of the longitudinal blade extent BLE would taper off towards the second blade end 13. In this embodiment both longitudinal sides of the blade taper off towards the second blade end 13 but in another embodiment only one side would taper off or the two sides would taper off at different angles. In this embodiment both sides are tapering off in straight lines but in another embodiment the tapering sides could comprise serration or other curves or other e.g. to ease the blades motion through the soil, to better cut through roots, or other.

[0087] In this embodiment the blade comprise connection means 19 in the form of two through going holes enabling that the ground engaging blade 11 can be securely and releasably connected to the bracket 8 by means of bolts and nut. However, in another embodiment the through going holes could comprise thread so that the blades 11 could be connected by means of bolts or screws. In this embodiment the blade 11 comprises two holes arranged along the longitudinal middle of the blade but in another embodiment the blade 11 could comprise another number of holes - such as one, three, five eight or even more, e.g., to enable that the blade could be connected in different angles to the bracket 8 - and / or the holes could be arranged differently on the blade 11 e.g., depending on the bracket and / or the blade design, on the specific use, or other.

[0088] In this embodiment the blade 11 is made from tempered steel, but in another embodiment the blade 11 could be made from carbon steel, boron steel, stainless steel or another steel material - e.g., heat-treated / hardened - and / or the blade 11 could also or instead be made from another metal - such as tungsten, aluminium, titanium or other - and / or the blade 11 could also or instead be made from a composite material - e.g. fibre reinforced, plastic, rubber or any combination thereof.

[0089] The invention has been exemplified above with reference to specific examples of main frames 2, booms 5, 16, brackets 8, ground engaging blades 11 and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims. Figure references

[0090] 1. Tillage tool

[0091] 2. Main frame

[0092] 3. Ground surface

[0093] 4. Travel direction

[0094] 5. Boom

[0095] 6. Boom rotational axis

[0096] 7. Tool arm

[0097] 8. Bracket

[0098] 9. First bracket end

[0099] 10. Second bracket end

[0100] 11. Ground engaging blade

[0101] 12. First blade end

[0102] 13. Second blade end

[0103] 14. Radially outer part of ground engaging blade

[0104] 15. Tool arm circle

[0105] 16. Further boom

[0106] 17. Further tool arm

[0107] 18. Further boom tool arm circle

[0108] 19. Releasable mechanical connection means

[0109] 20. Vehicle connections means

[0110] 21. Motor vehicle

[0111] 22. Fixation means

[0112] 23. Bearing

[0113] 24. Further boom rotational axis

[0114] 25. Connection holes

[0115] BOA. Boom angle

[0116] BRE. Longitudinal bracket extent

[0117] BLE. Longitudinal blade extent

[0118] BLA. Blade angle

[0119] BLR. Blade radius BLTR. Blade tip radius

[0120] BRA. Bracket angle

[0121] RR. Root radius

[0122] FBA. Further boom angle

[0123] OBR. Outer boom radius

[0124] BLW. Blade width

[0125] BRW. Bracket width

[0126] BRR. Bracket tip radius

[0127] RCR. Rolling circumference radius

Claims

Claims1. A tillage tool (1) comprising, a main frame (2) arranged to be propelled over a ground surface (3) in a travel direction (4), a boom (5) rotatably connected to said main frame (2), wherein a boom rotational axis (6) of said boom (5) is arranged askew in a boom angle (BOA) in relation to said travel direction (4), and two or more tool arms (7) each comprising, a bracket (8) having a longitudinal bracket extent (BRE) with a first bracket end (9) and a second bracket end (10) arranged at opposite ends of said longitudinal bracket extent (BRE) of said bracket (8), and a ground engaging blade (11) having a longitudinal blade extent (BLE) with a first blade end (12) and a second blade end (13) arranged at opposite ends of said longitudinal blade extent (BLE) of said ground engaging blade (11), wherein said two or more tool arms (7) are each connected to said boom (5) at said first bracket end (9) so that said second bracket end (10) is extending radially away from said boom (5), wherein said first blade end (12) of said ground engaging blade (11) is connected to said bracket (8) at said second bracket end (10) so that said second blade end (13) is extending further radially away from said boom (5) than said second bracket end (10), and wherein said longitudinal blade extent (BLE) is arranged askew in a blade angle (BLA) in relation to said longitudinal bracket extent (BRE) so that said longitudinal blade extent (BLE) is aligned with said travel direction (4) within a tolerance of plus / minus 15°, preferably within plus / minus 10° when said bracket (8) is extending radially in said travel direction (4).

2. A tillage tool (1) according to claim 1, wherein said ground engaging blade (11) comprises a curvature so that said second blade end (13) of said ground engaging blade (11) is bent downwards when said bracket (8) is extending radially in said travel direction (4).

3. A tillage tool (1) according to claim 2, wherein a radially outer part (14) of said ground engaging blade (11) is provided with a bend having a blade radius (BLR) of between 25% and 95%, preferably between 35% and 85%, and most preferred between 45% and 75% of a blade tip radius (BLTR) of said ground engaging blade (11) to form said curvature, wherein said blade tip radius (BLTR) is the distance between said boom rotational axis (6) and a radially outermost tip of said ground engaging blade (11).

4. A tillage tool (1) according to any of the preceding claims, wherein said bracket (8) is extending radially in a forward rotational direction as seen when said main frame (2) is propelled in said travel direction (4) during normal use of said tillage tool (1).

5. A tillage tool (1) according to claim 4, wherein said bracket (8) is extending radially in said forward rotational direction in a bracket angle (BRA) of between 4° and 65°, preferably between 6° and 55°, and most preferred between 8° and 45°, wherein said bracket angle (BRA) is measured between said longitudinal bracket extent (BRE) of said bracket (8) and a root radius (RR) extending between said boom rotational axis (6) and a root of said bracket’s longitudinal bracket extent (BRE) at said first bracket end (9).

6. A tillage tool (1) according to any of the preceding claims, wherein said two or more tool arms (7) are angularly evenly distributed around said boom (5).

7. A tillage tool (1) according to any of the preceding claims, wherein said tillage tool (1) includes three or more tool arms (7) which are angularly evenly distributed around the boom (5).

8. A tillage tool (1) according to any of the preceding claims, wherein said two or more tool arms (7) are mutually angularly displaced around said boom (5) and arranged at the same axial position on said boom (5) to form a tool arm circle (15).

9. A tillage tool (1) according to claim 8, wherein said tool arm circle (15) comprises between two or fourteen, preferably between four and twelve, and most preferred between six and ten tool arms (7).

10. A tillage tool (1) according to claim 8 or 9, wherein said boom (5) comprises at least two tool arm circles (15) wherein said at least two tool arm circles (15) are axially displaced in relation to each other on said boom (5).

11. A tillage tool (1) according to any of the preceding claims, wherein said boom angle (BOA) is between 25° and 85°, preferably between 35° and 80°, and most preferred between 45° and 75°, wherein said boom angle (BOA) is the smallest angle measured between said travel direction (4) and said boom rotational axis (6).

12. A tillage tool (1) according to any of the preceding claims, wherein said tillage tool (1) comprises a further boom (16) rotatably connected to said main frame (2), wherein said further boom (16) comprises two or more further tool arms (17), wherein a further boom rotational axis (24) of said further boom (16) is arranged askew in a further boom angle (FBA), wherein said further boom angle (FBA) is a mirror of said boom angle (BOA) around a plane perpendicular to said travel direction (4).

13. A tillage tool (1) according to claim 12, wherein said further tool arms (7) are mutually angularly displaced around said further boom (16) and arranged at the sameaxial position on said boom (5) to form a further boom tool arm circle (18) and wherein said further boom tool arm circle (18) is displaced from a tool arm circle (15) of said boom (5) as seen in said travel direction (4).

14. A tillage tool (1) according to any of the preceding claims, wherein said first blade end (12) of said ground engaging blade (11) is connected to said bracket (8) at said second bracket end (10) by means of releasable mechanical connection means (19).

15. A tillage tool (1) according to any of the preceding claims, wherein at least a radially outer part (14) of said ground engaging blade (11) tapers off towards said second blade end (13).

16. A tillage tool (1) according to any of the preceding claims, wherein said boom (5) is connected to said main frame (2) so that said boom rotational axis (6) is substantially parallel with said ground surface (3) during normal use of said tillage tool (1).

17. A tillage tool (1) according to any of the preceding claims, wherein said main frame (2) comprises vehicle connections means (20) arranged for connecting said tillage tool (1) to a motor vehicle (21) to propel said main frame (2) over said ground surface (3) in said travel direction (4).

18. A tillage tool (1) according to any of the preceding claims, wherein said longitudinal blade extent (BLE) is arranged askew in said blade angle (BLA) in relation to said longitudinal bracket extent (BRE) in that a blade centreline extending along the middle of said longitudinal blade extent (BLE) of said ground engaging blade (11) is arranged askew in said blade angle (BLA) in relation to a bracket centreline extending along the middle of said longitudinal bracket extent (BRE) of said bracket (8).

19. A tillage tool (1) according to any of the preceding claims, wherein said blade angle (BLA) between said longitudinal blade extent (BLE) and said longitudinalbracket extent (BRE) is between 10° and 70°, preferably between 17° and 60°, and most preferred between 25° and 50°, wherein said blade angle (BLA) is measured between said longitudinal blade extent (BLE) and said longitudinal bracket extent (BRE) on the side radially furthest away from said boom rotational axis (6).

20. A tillage tool (1) according to any of the preceding claims, wherein said bracket (8) and / or said ground engaging blade (11) comprise fixation means (22) enabling that said longitudinal blade extent (BLE) of said ground engaging blade (11) can be arranged askew in said blade angle (BLA) in relation to said longitudinal bracket extent (BRE) on both sides of said longitudinal bracket extent (BRE).

21. A tillage tool (1) according to any of the preceding claims, wherein an outer boom radius (OBR) of said boom (5) is between 5% and 80%, preferably between 10% and 60%, and most preferred between 15% and 40% of a bracket tip radius (BRR) of said bracket (8), wherein said bracket tip radius (BRR) is the distance between said boom rotational axis (6) and an radially outermost tip of said bracket (8) and wherein said outer boom radius (OBR) is the distance between said boom rotational axis (6) and a radially outermost extent of said boom (5) at which said first bracket end (9) of said bracket (8) is connected to said boom (5).

22. A tillage tool (1) according to any of the preceding claims, wherein a blade width (BLW) of said ground engaging blade (11) at a part of said ground engaging blade (11) extending further radially away from said boom (5) than said second bracket end (10) is between 10% and 85%, preferably between 20% and 78%, and most preferred between 35% and 70% of a bracket width (BRW) of said bracket (8), wherein said blade width (BLW) is the width of said ground engaging blade (11) as measured in a direction transversal to said longitudinal blade extent (BLE) and wherein said bracket width (BRW) is the width of said bracket (8) as measured in a direction transversal to said longitudinal bracket extent (BRE).

23. A tillage tool (1) according to any of the preceding claims, wherein a bracket tip radius (BRR) of said bracket (8) is between 15% and 90%, preferably between 25% and 75%, and most preferred between 35% and 65% of a blade tip radius (BLTR) of said ground engaging blade (11), wherein said bracket tip radius (BRR) is the distance between said boom rotational axis (6) and an radially outermost tip of said bracket (8) and wherein said blade tip radius (BLTR) is the distance between said boom rotational axis (6) and a radially outermost tip of said ground engaging blade (11).

24. Use of a tillage tool (1) according to any of the preceding claims for ploughing soil.

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