Cutting element, use of it and mobile cutting device with it

Description

[0001] The present invention relates to a cutting element which is designed such that blades of grass or other organic blade materials on a vegetation surface can be cut, comprising a base body which is formed by a base body material, and cutting bodies formed on opposite sides of the base body.

[0002] The present invention further relates to a use of a cutting element for cutting grass blades or other organic blade materials on a vegetation surface.

[0003] Finally, the present invention relates to a mobile cutting device, in particular a combine harvester or robotic lawnmower, comprising a rotor and at least one cutting element fastened thereto in such a way that blades of grass or other organic blade materials on a vegetation surface can be cut by the cutting element by rotation of the rotor.

[0004] A cutting element of the type mentioned above is already known, for example, in the form of a lawnmower blade from EP 3 273 766 A1, i.e., as a cutting element for cutting blades of grass. These can be cut by such a cutting element; the corresponding plant fibers are thus cut and thus separated from the vegetation, in this case, a lawn. This is different from the machining of metals or the like, where, in the manner of a plow and thus a correspondingly shaped cutting element penetrates a metal to produce a chip. The corresponding cutting body of the suitable cutting elements is therefore rather blunt and usually optimized for chip removal. When cutting blades of grass and other organic blade materials, however, the sharpness of the cutting bodies is more important to produce a clean cut.

[0005] In the previously known lawnmower blade, overload protection is implemented by a long slot into which a rotor pin engages eccentrically. The lawnmower blade can thus pivot around the pin and slide along it upon impact with a stone. After such a rotation, another of its cutting elements is then actively arranged to cut the grass blades, without having to change the direction of rotation of the rotor that drives the lawnmower blade.

[0006] JP H04 106925 U relates to a cutting tool attached to a lawn mower.

[0007] US 2014 / 130473 A1 relates to a rotating device comprising a metallic body.

[0008] EP 2 810 548 A1 relates to a cutting element for a mowing machine.

[0009] WO 2019 / 096539 A1 relates to a cutting tool with a cutting area made of a hard metal.

[0010] US 2014 / 013915 A1 concerns a steel plate for a strip-shaped punching knife.

[0011] The risk of breakage is reduced accordingly. However, this does not change the fact that the cutting elements of the familiar lawn mower blade are subject to normal wear and tear when cutting grass blades and other organic material.

[0012] The object of the present invention is therefore to provide a cutting element of the type mentioned at the outset, a use of the type mentioned at the outset and a mobile cutting device, in particular a combine harvester or robotic lawnmower of the type mentioned at the outset, each with a longer service life in the region of the cutting body or bodies compared to the prior art.

[0013] The object is achieved by a cutting element according to claim 1. Advantageous further developments thereof are specified in the claims dependent on claim 1.

[0014] The cutting element, which is designed such that blades of grass or other organic blade materials on a vegetation surface can be cut, comprises a base body which is formed by a base body material, and cutting bodies formed on opposite sides of the base body, wherein at least one of the cutting bodies is formed by a cutting body material which is different from the base body material, is sintered and harder than the base body material, wherein the sintered cutting body material is formed by a hard metal or cermet and the higher hardness thereof is based on hard material particles therein.

[0015] This is advantageous because such a cutting element is hard where wear reduction is important, i.e., in the area of ​​one of the cutting elements, and softer where the cutting element's flexibility is important to prevent breakage, i.e., in the area of ​​the base body. The latter measure provides a dampening effect on collision energy.

[0016] Cemented carbide and cermet are both composite materials in which the hard material particles, which make up the predominant component of the composite material, form a skeleton or framework structure whose interstices are filled with a more ductile metallic binder. The hard material particles can in particular be formed at least predominantly from tungsten carbide, titanium carbide and / or titanium carbonitride, although other hard material particles, in particular carbides of elements from groups IV to VI of the periodic table, can also be present in smaller quantities. The ductile metallic binder usually consists at least predominantly of cobalt, nickel, iron or a base alloy of at least one of these elements. However, other elements can also be dissolved in the metallic binder in smaller quantities.A base alloy is understood to mean that this element forms the predominant component of the alloy. The most commonly used material is cemented carbide, in which the hard material particles are at least predominantly composed of tungsten carbide and the metallic binder is a cobalt or cobalt-nickel-based alloy; the weight fraction of the corresponding tungsten carbide particles is in particular at least 70 weight percent, preferably more than 80 weight percent.

[0017] In the context of the present disclosure, skeletal structure means that the hard material particles, for example hard material particles formed essentially by tungsten carbide, form a coherent particle network where any hard material particle touches at least one other hard material particle.

[0018] It is particularly advantageous if at least two of the cutting bodies are made of the sintered cutting body material, because this further reduces wear, for example, when reversing the cutting direction of the cutting element. This is possible because the sintered cutting bodies are formed on opposite sides. Even more preferably, the cutting bodies on all opposite sides of the base body are formed from the sintered cutting body material, i.e., cemented carbide or cermet.

[0019] The base body is advantageously plate-shaped and has a larger surface area than the cutting elements in a plate plane of the base body, as this further reduces the risk of fracture of the sintered cutting element, i.e., the cemented carbide or cermet. Accordingly, the base body in the cutting plane provides sufficient damping of the sintered cutting element made of cemented carbide or cermet when it collides with a hard object, such as a stone.

[0020] For the purposes of the present disclosure, the terms "opposite sides" and the like refer in particular to the sides of the base body which are parallel or diagonally opposite one another, such as the corresponding sides of a square, rectangle, triangle, trapezoid or parallelogram, and also the sides of shapes which substantially correspond to the aforementioned shapes.

[0021] The term hardness refers to the resistance to penetration of a harder test specimen into the cutting body material and the base body material.

[0022] By sintering the at least one cutting body, it can advantageously be formed independently of the base body because the corresponding green body can be formed before sintering. This, in addition to reducing wear, improves cutting performance by adapting the geometry of the cutting body. This contrasts with applying the cutting body using a deposition process, where the cutting body inherits the shape of the base body in the area of ​​the side on which it is to be formed.

[0023] Because the cutting bodies are formed on opposite sides of the base body, the sintered cutting body made of hard metal or cermet is actively cutting during a cutting movement of the cutting element, while another of the cutting bodies, which is optionally formed from the sintered cutting body material, is passive in cutting. Upon reversing the cutting movement, the sintered cutting body made of hard metal or cermet is passive in cutting and the other cutting body is active in cutting. According to the present disclosure, the cutting element can therefore cut the grass blades or other organic blade material in two different cutting directions, for example, clockwise and vice versa.Because the cutting bodies are formed on opposite sides, the sintered cutting body made of cemented carbide or cermet is actively cutting during the cutting movement, while another cutting body, which is optionally formed from the sintered cutting body material, is passive in cutting. When the installation position of the cutting element is changed and the cutting movement is maintained, the sintered cutting body made of cemented carbide or cermet is passive in cutting, while the other cutting body is actively cutting. The installation position can be achieved by rotating the base body, in which its original underside is rotated upward and its original top side is rotated downward, i.e., the base body is turned around a rotation axis that lies in the cutting plane.Alternatively or additionally, the installation position can be realized by a centric or eccentric rotation of the base body relative to a center of mass of the base body, i.e., by a rotation about an axis perpendicular to the cutting plane. In the latter case, the base body is set into a longitudinal movement by the rotation, for example, in the manner of an eccentric, so that the two installation positions are symmetrical to each other, as is also possible with centric rotation without longitudinal movement of the base body.

[0024] The other organic stalk materials include in particular other grasses, such as cereals, in particular wheat, rye, barley, oats and maize, but also sugar cane, reeds and the like.

[0025] According to a further development of the cutting element, the hard material particles of the cemented carbide are essentially formed by tungsten carbide. This is advantageously a particularly hard material, which further reduces wear and thus increases the service life. The weight proportion of the corresponding tungsten carbide particles, which can also be referred to as tungsten carbide grains, with respect to the overall composition of the sintered cutting body material made of the cemented carbide is preferably in the range from 70 weight percent up to and including 99 weight percent, even more preferably from 80 weight percent up to and including 99 weight percent, most preferably from 85 weight percent up to and including 99 weight percent; a range from 88 weight percent up to and including 99 weight percent is also conceivable and possible.However, other additional hard material particles formed by carbides or carbonitrides of metals from groups IV to VI of the periodic table are also conceivable and possible.

[0026] According to a further development of the cutting element, a binder is formed in the spaces between the hard material particles of the cemented carbide or cermet, consisting of cobalt, nickel, and / or iron, or a base alloy of one of these elements. A base alloy of a metal means that this metal forms the main component of the alloy. In addition to the elements mentioned, other elements can be dissolved in the binder in smaller quantities.

[0027] According to a further development of the cutting element, the sintered cutting body made of cemented carbide or cermet is integrally bonded to the base body. This is advantageous because the sintered cutting body made of cemented carbide or cermet can be replaced with another, similarly constructed cutting body by loosening the corresponding connection, should such a replacement become necessary despite the increased wear resistance. "Integrally bonded" means, for example, that the sintered cutting body made of cemented carbide or cermet is soldered, glued, or welded to the side of the base body.

[0028] According to a further development of the cutting element, the sintered cutting body made of hard metal or cermet is bonded to the base body by melting at least the base body material through the action of an energy beam. This provides a particularly stable connection between the cutting body and the base body. The energy beam can be, for example, a laser beam or an electron beam.

[0029] According to a further development of the cutting element, the sintered cutting body made of hard metal or cermet has a wedge angle which is less than or equal to 60° and greater than 0°, preferably less than or equal to 45° and greater than or equal to 15°. This makes the sintered cutting body made of hard metal or cermet particularly sharp; the individual values ​​of these ranges, i.e. all wedge angles from greater than 0° up to and including 60°, are also disclosed here. The cutting edge of the sintered cutting body made of hard metal or cermet thus formed can be symmetrical, with a cross-section shaped as an equilateral or isosceles triangle, or asymmetrical, with a cross-section shaped, for example, as a right-angled triangle. Symmetrical cutting edges have particularly stable cutting properties, while asymmetrical ones have particularly sharp cutting properties.

[0030] According to a further development of the cutting element, the hard material particles have an average grain size of 0.5 µm to 2 µm, preferably 0.8 µm to 1.3 µm. This is particularly advantageous for cutting grass blades or other organic blade materials on the vegetation surface, because the grain size range of 0.5 µm to 2 µm, preferably 0.8 µm to 1.3 µm, makes the cutting body material harder and more wear-resistant, as well as increasing the fracture stress. The cutting body material can therefore be manufactured with a sharper cut, cutting the grass blades more precisely and staying sharp for longer. This is further improved if the hard material particles of the cemented carbide are primarily made of tungsten carbide.The weight fraction of the tungsten carbide particles can in particular be in the range from 70 weight percent up to and including 99 weight percent, even more preferably from 80 weight percent up to and including 99 weight percent, most preferably from 85 weight percent up to and including 99 weight percent; a range from 88 weight percent up to and including 99 weight percent is also conceivable and possible.

[0031] For the purposes of the present disclosure, "essentially formed by tungsten carbide" means that at least 90% of the hard material particles are formed by tungsten carbide, preferably 95%, most preferably 99%. The same applies to cases in which the hard material particles are essentially formed by another hard material phase.

[0032] In this disclosure, grain size is measured as "linear intercept length" according to the international standard ISO 4499-2:2008(E). EBSD (electron back-scatter diffraction) images were used as the basis. The measurement methodology for such images is described, for example, in: KP Mingard et al., "Comparison of EBSD and conventional methods of grain size measurement of hard metals," Int. Journal of Refractory Metals & Hard Materials 27 (2009) 213-223.

[0033] According to a further development of the cutting element, the sintered cutting body made of the hard metal or cermet is formed as a one-piece cutting bar, which extends essentially along the entire side of the base body on which it is formed. This is a particularly expedient measure that increases cutting performance. Preferably, at least the cutting body opposite the cutting bar formed in this way is also made of the sintered cutting body material, i.e., the hard metal or cermet, and shaped as such a cutting bar.

[0034] According to a further development of the cutting element, at least one of the sides of the base body is essentially straight, concave when viewed from the outside, or forms a V-shape with the opposite side of the base body, with the sintered cutting body made of hard metal or cermet being formed on the side thus shaped. These are particularly expedient shapes of the base body or of the sintered cutting body made of hard metal or cermet. In the case of the concave side and the V-shape, the mass of the cutting element can advantageously be reduced. This increases the service life because the collision energy is correspondingly reduced when the cutting element collides with a stone or the like. Two of the opposite sides of the base body can also be formed essentially parallel to one another, with the sintered cutting body being formed on one of these sides.

[0035] According to this further development of the cutting element, in the case of the V-shape, for example, the base body is essentially triangular in shape, a recess provided in the base body, into which a pin of a rotor can engage, is essentially triangular in shape, the corners of the recess are rounded and these are arranged symmetrically around a center of gravity of the base body.

[0036] According to a further development of the cutting element, the base body material is formed from steel. This is advantageous because steel has a particularly good combination of ductility, toughness, and strength, thus reducing the risk of fracture of the sintered cutting body material while maintaining sufficient dimensional stability of the cutting element, especially when its hard material particles are formed from tungsten carbide and the binder is formed from cobalt, nickel, and / or iron, or a base alloy of one of these elements. Cobalt or the base alloy thereof is particularly advantageous.

[0037] According to a further development of the cutting element, the base body has at least one recess designed to fasten the cutting element to a rotor. This allows the cutting element to be advantageously operated with a mobile cutting device, for example a combine harvester, mobile robotic lawnmower, or another hand-held cutting device that has the rotor. The recess can be formed by one or more bores that break through the base body so that a pin of the rotor can be inserted through the cutting element, wherein the cutting element is in particular freely rotatably engaged with the pin, eccentrically relative to the center of gravity of the cutting element. The cutting element can thus be oriented outwards by the centrifugal force caused by rotation of the rotor.If several recesses are provided, for example, two, three, four, or five, especially in the case of corresponding bores, it is therefore expedient for these to be arranged eccentrically and at the same time symmetrically around a center of gravity of the cutting element. If a recess is formed, it can be formed by several bores that intersect at a center of gravity of the cutting element.

[0038] According to a further development of the cutting element, the recess is formed between two opposite sides of the base body, with the sintered cutting body made of hard metal or cermet being formed on one of these sides. This advantageously reduces the mass of the cutting element because a separate area, for example, in the form of a projection of the base body, is avoided. This reduces the collision energy and thus increases the service life.

[0039] However, it is also conceivable and possible for this projection to be realized in another embodiment, whereby the recess, or at least one of them, is formed outside the opposite sides on which the cutting bodies are formed. The advantage of this is that the effective cutting length in the longitudinal direction of the cutting body(s) is increased.

[0040] According to a further development of the cutting element, the recess has at least two rounded regions. Each of the rounded regions forms a pivot bearing for rotating the cutting element around a rotor pin. The rounded regions are connected to one another by a differently shaped connecting side of the recess. The sintered cutting body made of hard metal or cermet is formed on the side of the base body opposite the connecting side or one of the rounded regions. This allows the cutting element to be rotated particularly advantageously around the pin in order to align it using centrifugal force and, at the same time, to be flexibly supported on it in the event of a collision between the sintered cutting body made of hard metal or cermet and a hard object, which in the latter case increases the service life.On the other hand, the cutting element, and thus the base body, can slide on the journal from one rounded area to the other rounded area along the differently shaped side of the recess. As a result, when the sintered cutting body made of hard metal or cermet collides with a stone during rotation of the rotor, part of the rotary motion of the cutting body is converted into a translational motion, similar to an eccentric. After a full rotation around the journal, the sintered cutting body made of hard metal or cermet is passive in terms of cutting, and an opposing cutting body, which may also be formed from the sintered cutting body material, is active in terms of cutting, or vice versa.It is particularly advantageous if the recess formed in this way is symmetrical about the center of gravity of the cutting element, for example symmetrical in the sense of a rotation of 180°, 90° or even higher rotational symmetry, so that after a corresponding rotation the recess is aligned with itself; the axis of rotation pierces the center of gravity of the cutting element and is perpendicular to the cutting plane.

[0041] One or more of the rounded areas form the respective pivot bearing, in particular because they surround the pin in sections.

[0042] A pin, for example, is formed by a cylindrical element within the meaning of the present disclosure; a rotor, for example, is formed by a disc-shaped body, where the pin is eccentrically connected to the disc and a designated axis of rotation pierces this body centrally perpendicular to the disc plane. If the pin is cylindrical, the rounded area(s) is / are preferably formed following such a shape when viewed from within the recess.

[0043] According to a further development of the cutting element, the connecting side is convexly curved in the direction of view, and one of the rounded areas is located opposite the side of the base body on which the sintered cutting body made of hard metal or cermet is formed. The pin can then slide along the convex connecting side. This is particularly advantageous when the base body is essentially triangular, three rounded areas are provided, and these are accordingly connected by a total of three of the convex connecting sides, thus the recess has the shape of a triangle with rounded corners and, viewed from the inside, convex sides.This allows a total of three cutting elements to be formed on opposite sides of the base body, at least one of which is the sintered cutting element made of hard metal or cermet. In the event of a collision, the cutting elements can switch from an active cutting position to a passive cutting position to protect the cutting element, because the recess is designed for corresponding rotational and longitudinal movement. It is particularly advantageous if the recess formed in this way is symmetrical around the center of gravity of the cutting element.

[0044] According to a further development of the cutting element, the connecting side is essentially straight and lies opposite the side of the base body on which the sintered cutting body made of hard metal or cermet is formed. The pin can then slide along the straight connecting side. This is particularly advantageous when the base body is essentially rectangular or square, two rounded areas are provided and these are accordingly connected by a total of two of the straight connecting sides, i.e. the recess has the shape of a rectangle or square with rounded corners and straight sides. In the case of a rectangle, the recess is therefore elongated, approximately in the sense of a longitudinal bore with rounded corners. In both cases, the straight connecting sides preferably run essentially parallel to the side of the base body on which the sintered cutting body made of hard metal or cermet is formed.In both cases, a total of two cutting elements can be formed on two opposite sides of the base body, at least one of which is the sintered cutting element made of cemented carbide or cermet. In the event of a collision, the cutting elements can switch from an active cutting position to a passive cutting position to protect the cutting element, because the recess is designed for corresponding rotational and longitudinal movement. It is particularly advantageous if the recess formed in this way is symmetrical around the center of gravity of the cutting element.

[0045] This development is further improved if two of the opposite sides of the base body are formed substantially parallel to each other, the sintered cutting body made of the hard metal or cermet is formed on one of these sides and the recess is formed elongately such that its long sides extend substantially parallel to the substantially parallel side of the base body.

[0046] The object is also achieved by the use according to claim 14, i.e., the use of at least one cutting element according to claim 1 or a claim dependent thereon or the developments or embodiments of the cutting element disclosed here for cutting blades of grass or other organic blade materials on a vegetation surface. The cutting element is thus used for cutting these materials, wherein the sintered cutting body made of hard metal or cermet is preferably cutting-active or becomes cutting-active by changing the installation position of the cutting element, whether by rotation about a rotational axis perpendicular or parallel to the cutting plane. When used for cutting blades of grass, this can also be considered lawn mowing.Even more preferably, the cutting element is used together with a rotor of a mobile cutting device, to which it is attached in a wing-like manner, in particular to a pin thereof, most preferably it is attached to the pin eccentrically, for example freely rotatable and alignable by centrifugal force.

[0047] The object is also achieved by the mobile cutting device, in particular a combine harvester or robotic lawnmower, according to claim 15.

[0048] The mobile cutting device, in particular the robotic lawnmower, comprises a rotor and at least one cutting element fastened thereto according to claim 1 or a dependent claim thereon or the developments or embodiments disclosed here such that, by rotating the rotor, blades of grass or other organic blade materials on a vegetation surface can be cut by the cutting element. The mobile cutting device can be, for example, a mower, for example a combine harvester, and the robotic lawnmower can be, for example, a self-propelled one with a chassis, a drive therefor, a chassis, the rotor, and a drive therefor, which is particularly preferably designed for lawn mowing.In the case of the robotic lawnmower, the cutting element is attached to the rotor in a vane-like manner, in particular to a pivot thereof. Most preferably, it is attached to the pivot eccentrically, for example, freely rotatable and alignable by centrifugal force. It is conceivable and also possible for the mobile cutting device to be designed to be directly hand-operated, for example, as a pair of lawn shears.

[0049] Further advantages and benefits of the invention will become apparent from the following description of embodiments with reference to the accompanying figures.

[0050] The figures show: Fig. 1: a perspective schematic representation of a cutting element with a rectangular base body, cutting bodies formed on two opposite sides thereof, and an elongated recess according to the prior art; Fig. 2: a perspective schematic representation of a cutting element with a rectangular base body made of steel, cutting bodies made of a sintered hard metal formed on two opposite sides thereof, and an elongated recess according to a first embodiment; Fig. 3: a perspective schematic representation of a cutting element with a rectangular base body made of steel, cutting bodies made of a sintered hard metal formed on two opposite sides thereof, and a round recess according to a second embodiment; Fig.Fig. 4: a perspective schematic representation of a cutting element with a rectangular base body made of steel, cutting bodies made of a sintered hard metal formed on two opposite sides thereof, and two round recesses according to a third embodiment; Fig. 5: a perspective schematic representation of a cutting element with a trapezoidal base body made of steel, cutting bodies made of a sintered hard metal formed on two opposite sides thereof, and two round recesses according to a fourth embodiment; Fig. 6: a perspective schematic representation of a cutting element with a rectangular base body made of steel, cutting bodies made of a sintered hard metal formed on two opposite sides thereof, a plate-shaped extension of the base body, and a round recess therein according to a fifth embodiment; Fig.Fig. 7: a perspective schematic representation of a cutting element with a triangular base body made of steel, cutting bodies made of a sintered hard metal formed on three opposite sides thereof, and three recesses according to a sixth embodiment; and Fig. 8: a perspective schematic representation of a cutting element with a triangular base body made of steel, cutting bodies made of a sintered hard metal formed on three opposite sides thereof, and a recess in the shape of a triangle with rounded corners and, viewed from the inside, convex sides according to a seventh embodiment.

[0051] In the Fig. 1 bis 8 Identical, similar or equivalent elements are designated by identical reference numerals and a repeated description of these elements is avoided in the following description in order to avoid redundancies.

[0052] Fig. 1 shows a representation of a cutting element 1 according to the prior art. The cutting element 1 has a plate-shaped, rectangular base body 2. Two of the opposite long sides of the base body 2 each taper symmetrically outwards in a wedge shape. This accordingly forms two opposing cutting bodies 3, through which blades of grass as well as other organic blade materials such as grain, sugar cane, or reeds can be cut. For this purpose, an elongated recess 4 of the base body 2 is brought into engagement with a pin (not shown) of a rotor (not shown) of a cutting device (not shown), for example, a robotic lawnmower. If the rotor is rotated sufficiently fast, the cutting element 1 aligns radially outward with respect to a rotational axis of the rotor; the rotational axis here is perpendicular to the plate plane of the base body 2.The pin is located in one of the rounded areas of the recess 4, which are each formed by two rounded corners of the recess and form a pivot bearing for rotating the cutting element 1 on and around the pin. The cutting element 1 is therefore mounted eccentrically on the pin because the center of gravity of the cutting element 1 is located in the middle of the recess 4, which is therefore shaped symmetrically around the center of gravity of the cutting element 1. If one of the two cutting bodies 3 collides with a stone while cutting the blades of grass, the cutting element 1 is rotated around the pin and at the same time slides along the long sides of the recess 4, in the case of a thin pin on only one of these sides, towards the other rounded area of ​​the recess 4. The cutting body 3 which collided with the stone is then with respect to the direction shown in . Fig. 1 selected view on the other side, i.e. cutting passively, whereas the other cutting body 3, which was facing away from the stone, now takes the position of the cutting body 3 that collided with the stone, i.e. is positioned cutting actively.

[0053] In Fig. 1 It is particularly clearly visible that the cutting bodies 3 are monolithically connected to the base body 2 without any material seams, i.e., they are formed from the base body 2. The cutting bodies 3 and the base body 2 are therefore made of the same material.

[0054] Fig. 2 shows a representation of a cutting element 1' according to a first embodiment. The cutting element 1' has a plate-shaped, rectangular base body 2', corresponding to the cutting element 1. A wedge-shaped cutting body 3' is fastened to each of the opposite long sides of the base body 2' by means of an energy beam. However, it is also conceivable and possible for the cutting bodies 3' to be connected to the base body 2' by soldering. In contrast to the cutting bodies 3, the cutting bodies 3' are made of a sintered hard metal, are accordingly hard and wear-resistant, and are subsequently bonded to the base body 2', i.e., after their sintering; the hard material particles are formed by tungsten carbide, and the binder is cobalt. The base body 2', on the other hand, is made of steel, making it softer than the cutting bodies 3' and thus dampening the collision energy introduced into the cutting bodies 3' by means of dissipation.The functioning of the elongated recess 4' formed in the base body 2', whose long sides are arranged parallel to the sintered cutting bodies 3' or the corresponding sides of the base body 2' and whose rounded areas are connected to one another by these and act as a pivot bearing for the pin, corresponds to that of the recess 4 from the prior art.

[0055] In Fig. 2 It can be seen that the cutting elements 3' each taper symmetrically outward in a wedge shape, thus forming correspondingly symmetrical cutting edges. The wedge angle of these is less than 45° in each case.

[0056] Fig. 3 shows a representation of a cutting element 1" according to a second embodiment. The cutting element 1" differs from the cutting element 1' only in that a recess 4" in the base body 2' is different from the recess 4'. The recess 4" is round, as is obtainable by a single vertical bore with respect to the plate plane of the base body 2". The recess 4", like the recess 4', where it has the two rounded areas, serves as a pivot bearing into which the pin engages. Upon collision of one of the sintered cutting bodies 3' with the stone, the cutting element 1" is rotated around the pin, after which, after a full rotation (360°), the collided sintered cutting body 3' continues to be active in cutting.A change from the cutting-active cutting body 3' to the previously cutting-passive cutting body 3', because facing away from the stalk material, can be achieved by detaching the cutting element 1" from the pin, then rotating it by 180° about a rotation axis which is oriented parallel to one of the long sides of the base body 2", and finally connecting it to the pin in this position so that it can rotate freely.

[0057] Fig. 4 shows a representation of a cutting element 1‴ according to a third embodiment. The cutting element 1‴ differs from the cutting element 1" only in that two of the round recesses 4" are formed in the base body 2', diametrically opposed to each other and equidistant from the center of gravity of the cutting element 1‴, and that sintered cutting bodies 3" analogous to the sintered cutting bodies 3' each taper outward in a wedge shape, asymmetrically, thereby forming correspondingly asymmetrical cutting edges. The wedge angle of these is in each case less than 45°.

[0058] With the cutting element 1‴, a change from an active cutting body 3" to a previously passive cutting body 3" can be realized analogously to the cutting element 1", whereby the pin is engaged with the same recess 4" before and after the change. Alternatively, the change can also be realized by the cutting element 1‴ being released from the pin, being rotated by 180° about an axis of rotation that is perpendicular to the plate plane of the base body 2', and then the pin is inserted into the other of the recesses 4". The sintered cutting bodies 3", which consist of the material of the cutting bodies 3' and, like these, are integrally connected to the base body 2', connect to the base body 2' due to their asymmetrical shape at the Fig. 4 shown side of it in a flush manner, so that the cutting element 1‴ can also lie flat on the rotor in the area of ​​the sintered cutting bodies 3".

[0059] Fig. 5 shows a representation of a cutting element 1ʺʺ according to a fourth embodiment. The cutting element 1ʺʺ has a trapezoidal base body 2", which, like the base body 2', is made of steel. On the inclined sides thereof, the sintered cutting bodies 3' are materially connected to the base body 2", as in the other embodiments. The inclined sides form a V-shape. The round recess 4" is formed outside the center of gravity of the cutting element 1ʺʺ, so that in the cutting element 1ʺʺ, too, a centrifugal force-induced alignment thereof occurs radially outwards when the rotor rotates. The change from the cutting-active sintered cutting body 3' to a previously cutting-passive sintered cutting body 3', which then becomes cutting-active, is realized correspondingly for the cutting element 1".

[0060] Fig. 6 shows a representation of a cutting element 1ʺ‴ according to a fifth embodiment. In contrast to the cutting element 1", this has a rectangular, plate-shaped base body 2‴ with a plate-shaped, narrower extension 5 therefrom, which is located outside the sides of the base body 2‴, to which the sintered cutting bodies 3' are integrally connected; the base body 2‴ is formed from the steel of the other embodiments. The change from a cutting-active sintered cutting body 3' to a previously cutting-passive sintered cutting body 3', which then becomes cutting-active, is realized correspondingly for the cutting element 1". The round recess 4" is formed outside the center of gravity of the cutting element 1‴ʺ, so that in the cutting element 1ʺ‴, too, a centrifugal force-induced alignment thereof occurs radially outwards when the rotor rotates.

[0061] Fig. 7 shows a representation of a cutting element 1" according to a sixth embodiment. A plate-shaped base body 2" of the cutting element 1" is designed in the shape of a triangle with straight, cut-off corners. On the three main sides of the base body 2" which form a V-shape in pairs, a total of three of the sintered cutting bodies 3' are integrally connected to the base body 2" as in the other embodiments. Three of the round recesses 4" are arranged symmetrically around the center of gravity of the cutting element 1"‴. The change from a cutting-active sintered cutting body 3' to a previously cutting-passive sintered cutting body 3', which then becomes cutting-active, is realized by each recess 4" as such, corresponding to the cutting element 1', and alternatively by a change from the recess 4", which is originally in engagement with the pin, to another of the recesses 4''.Since each of the recesses 4" is formed outside the center of gravity of the cutting element 1‴ʺ, the cutting element 1‴‴ is also aligned radially outwardly due to centrifugal force when the rotor rotates for each engagement in one of the recesses 4".

[0062] Fig. 8 shows a representation of a cutting element 1‴ʺʺ according to a seventh embodiment. The cutting element 1‴ʺʺ differs from the cutting element 1‴‴ only in that a recess 4‴ is formed in the base body 2ʺʺ, the three corners of which are rounded and the three sides of which are convexly curved when viewed from the inside of the recess 4ʺʺ. Each of the rounded corners acts as a pivot bearing for the pin, corresponding to the recess 4", and is arranged opposite one of the sintered cutting bodies 3'. In the event of a collision, in which one of these cutting bodies 3' collides with a stone, the pin can slide along one of the convex sides until it engages with another of the rounded corners there. In accordance with the recess 4', such a sliding movement in combination with a rotation around the pin then causes one of the previously passive cutting bodies 3' to become active in cutting, and vice versa.

[0063] It is conceivable and also possible that the Fig. 2 bis 8 shown cutting elements 1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴ and 1‴ʺʺ, only one of the cutting bodies 3' or 3" is sintered and is formed by the hard metal.

Claims

1. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) configured such that it may be used to cut grass stalks or other organic stalk materials in a vegetation area, comprising a main body (2', 2", 2‴, 2ʺʺ) formed by a main body material and cutting bodies (3', 3") formed on opposite sides of the main body (2', 2", 2‴, 2ʺʺ), wherein at least one of the cutting bodies (3', 3ʺ) is formed by a cutting body material which is distinct from the main body material, is sintered and is harder than the main body material, characterized in that the sintered cutting body material is formed by a hardmetal or cermet and the higher hardness thereof is based on hard material particles present therein, wherein the hardmetal and the cermet are both composite materials in which the hard material particles, which make up the predominant constituent of the composite material, form a skeleton or framework structure, whose interspaces are filled by a binder that is more ductile in comparison.

2. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ. 1ʺʺʺ, 1‴) according to Claim 1, characterized in that the hard material particles of the hardmetal are substantially formed by tungsten carbide.

3. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) according to Claim 1 or 2, characterized in that a binder in interspaces between the hard material particles of the hardmetal or cermet is formed by cobalt, nickel and / or iron or an alloy based on one of these elements.

4. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) according to any of the preceding claims, characterized in that the sintered cutting body (3', 3") made of the hardmetal or cermet is joined to the main body (2', 2", 2‴, 2ʺʺ) by an atomic-level join.

5. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to any of the preceding claims, characterized in that the sintered cutting body (3', 3") made of the hardmetal or cermet is joined to the main body (2', 2", 2‴, 2ʺʺ) by an atomic-level join where at least the main body material has been melted by the action of an energy beam.

6. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) according to any of the preceding claims, characterized in that the sintered cutting body (3', 3") made of the hardmetal or cermet has a wedge angle of not more than 60° and more than 0°, preferably not more than 45° and not less than 15°.

7. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to any of the preceding claims, characterized in that the hard material particles have an average grain size of 0.5 µm to 2 µm, preferably 0.8 µm to 1.3 µm.

8. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) according to any of the preceding claims, characterized in that at least one of the sides of the main body (2', 2", 2‴, 2ʺʺ) is substantially straight or forms a V-shape with the opposite side of the main body (2', 2", 2‴, 2ʺʺ), wherein the sintered cutting body (3', 3") is formed from the hardmetal or cermet at the side of the main body (2', 2", 2‴, 2ʺʺ) having this shape.

9. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ,1‴ʺʺ) according to any of the preceding claims, characterized in that the main body material is formed by a steel.

10. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to any of the preceding claims, characterized in that the main body (2', 2", 2‴, 2ʺʺ) has at least one recess (4', 4", 4‴) configured for securing the cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) to a rotor.

11. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to Claim 10, characterized in that the recess (4', 4", 4‴) has at least two rounded regions, the rounded regions each form a pivot bearing for rotation of the cutting element (1', 1ʺ, 1‴, 1ʺʺ, 1‴ʺ,1ʺʺʺ, 1‴ʺʺ) around a pin of the rotor, the rounded regions are joined to one another by a distinctly formed connection side of the recess (4', 4ʺ, 4‴) and the sintered cutting body (3', 3ʺ) made of the hardmetal or cermet is formed at the side of the main body (2', 2ʺ, 2‴, 2ʺʺ) which is opposite the connection side or one of the rounded regions.

12. Cutting element (1', 1ʺ, 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to Claim 11, characterized in that the connection side has a convex curvature from an external point of reference and in that one of the rounded regions is opposite the side of the main body (2', 2", 2‴, 2ʺʺ) at which the sintered cutting body (3', 3") made of the hardmetal or cermet is formed.

13. Cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1ʺʺʺ, 1‴ʺʺ) according to Claim 11 or 12, characterized in that the connection side is substantially straight and is opposite the side of the main body (2', 2", 2‴, 2ʺʺ) at which the sintered cutting body (3', 3ʺ) made of the hardmetal or cermet is formed.

14. Use of at least one cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to any of Claims 1 to 13 for cutting grass stalks or other organic stalk materials in a vegetation area.

15. Mobile cutting apparatus, in particular a combine harvester or a robotic mower, comprising a rotor and at least one cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ) according to any of Claims 1 to 13 which is attached thereto in such a way that rotation of the rotor allows grass stalks or other organic stalk materials in a vegetation area to be cut by the cutting element (1', 1", 1‴, 1ʺʺ, 1‴ʺ, 1‴‴, 1‴ʺʺ).