Abstract
A cutting element is configured such that it may be used to cut grass stalks or other organic stalk materials in a vegetation area. The cutting element has a main body formed from a main body material and cutting bodies formed on opposite sides of the main body which have a longer service life in the region of the cutting body relative to the prior art. At least one of the cutting bodies 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. The sintered cutting body material is formed by a hard metal or cermet and the higher hardness thereof is based on hard material particles present therein.
Claims
1-15. (canceled)
16. A cutting element configured to cut grass stalks and other organic stalk materials in a vegetation area, the cutting element comprising: a main body formed from a main body material; and cutting bodies formed on opposite sides of said main body, at least one of said cutting bodies being formed from a cutting body material which is distinct from said main body material, is sintered and is harder than said main body material, wherein said cutting body material is formed by a hardmetal or cermet and a higher hardness thereof is based on hard material particles present in said cutting body material.
17. The cutting element according to claim 16, wherein said hard material particles of said hardmetal are formed from tungsten carbide.
18. The cutting element according to claim 16, further comprising a binder disposed in interspaces between said hard material particles of said hardmetal or said cermet and is formed from cobalt, nickel and/or iron or an alloy based on one of said cobalt, said nickel or said iron.
19. The cutting element according to claim 16, wherein said at least one cutting body made of said hardmetal or said cermet is joined to said main body by an atomic-level connection.
20. The cutting element according to claim 16, wherein said at least one body made of said hardmetal or said cermet is joined to said main body by an atomic-level connection where at least said main body material has been melted by an action of an energy beam.
21. The cutting element according to claim 16, wherein said at least one cutting body made of said hardmetal or said cermet has a wedge angle of not more than 60° and more than 0°.
22. The cutting element according to claim 16, wherein said hard material particles have an average grain size of 0.5 μm to 2 μm.
23. The cutting element according to claim 16, wherein: at least one side of said main body is straight or forms a V-shape with an opposite side of said main body; and said at least one cutting body formed from said hardmetal or said cermet at said side of said main body being straight or having said V-shape.
24. The cutting element according to claim 16, wherein said main body material is formed from steel.
25. The cutting element according to claim 16, wherein said main body has at least one recess formed therein and configured for securing the cutting element to a rotor.
26. The cutting element according to claim 25, wherein said recess has at least two rounded regions, said rounded regions each form a pivot bearing for rotation of the cutting element around a pin of the rotor, said rounded regions are joined to one another by a distinctly formed connection side of said recess and said at least one cutting body made of said hardmetal or said cermet is formed at a side of said main body which is opposite a connection side or one of said rounded regions.
27. The cutting element according to claim 26, wherein said connection side has a convex curvature from an external point of reference and in that one of said rounded regions is opposite said side of said main body at which said at least one cutting body made of said hardmetal or said cermet is formed.
28. The cutting element according to claim 26, wherein said connection side is straight and is opposite said side of said main body at which said at least one cutting body made of said hardmetal or said cermet is formed.
29. The cutting element according to claim 16, wherein said at least one cutting body made of said hardmetal or said cermet has a wedge angle of not more than 45° and not less than 15°.
30. The cutting element according to claim 16, wherein said hard material particles have an average grain size of 0.8 μm to 1.3 μm.
31. A method of cutting vegetation, which comprises the step of: providing the cutting element according to claim 16; and cutting grass stalks or other organic stalk materials in a vegetation area using the cutting element.
32. A mobile cutting apparatus, comprising: a rotor; at least one said cutting element according to claim 16, said at least one cutting element attached to said rotor in order that rotation of said rotor allows grass stalks or other organic stalk materials in a vegetation area to be cut by said at least one cutting element.
33. The mobile cutting apparatus according to claim 32, wherein the mobile cutting apparatus is a combine harvester or a robotic mower.
Description
[0046] In the figures:
[0047] FIG. 1: shows a perspective schematic representation of a cutting element having a rectangular main body, cutting bodies formed at two opposite sides thereof and an elongate recess according to the prior art;
[0048] FIG. 2: shows a perspective schematic representation of a cutting element having a rectangular main body made of a steel, cutting bodies made of a sintered hardmetal formed at two opposite sides thereof and an elongate recess according to a first embodiment;
[0049] FIG. 3: shows a perspective schematic representation of a cutting element having a rectangular main body made of a steel, cutting bodies made of a sintered hardmetal at two opposite sides thereof and a round recess according to a second embodiment;
[0050] FIG. 4: shows a perspective schematic representation of a cutting element having a rectangular main body made of a steel, cutting bodies made of a sintered hardmetal formed at two opposite sides thereof and two round recesses according to a third embodiment;
[0051] FIG. 5: shows a perspective schematic representation of a cutting element having a trapezoidal main body made of a steel, cutting bodies made of a sintered hardmetal formed at two opposite sides thereof and two round recesses according to a fourth embodiment;
[0052] FIG. 6: shows a perspective schematic representation of a cutting element having a rectangular main body made of a steel, cutting bodies made of a sintered hardmetal formed at two opposite sides thereof, a plate-shaped extension of the main body and a round recess therein according to a fifth embodiment;
[0053] FIG. 7: shows a perspective schematic representation of a cutting element having a triangular main body made of a steel, cutting bodies made of a sintered hardmetal formed at three opposite sides thereof and three recesses according to a sixth embodiment; and
[0054] FIG. 8: shows a perspective schematic representation of a cutting element having a triangular main body made of a steel, cutting bodies made of a sintered hardmetal formed at three opposite sides thereof and a recess in the shape of a triangle having rounded corners and sides that are convex when viewed from inside according to a seventh embodiment.
[0055] In FIGS. 1 to 8, elements that are the same, similar or have the same effect are denoted by identical reference numerals and repeated description of these elements is avoided in the following description to avoid redundancies.
[0056] FIG. 1 shows a representation of a cutting element 1 according to the prior art. The cutting element 1 has a plate-shaped rectangular main body 2. Two of the opposite long sides of the main body 2 each symmetrically narrow outwards in a wedge shape. This accordingly forms two opposite cutting bodies 3 by which grass stalks or else other organic stalk materials such as cereals, sugar cane or reeds can be cut. To this end an elongate recess 4 of the main body 2 is brought into engagement with a pin (not show) of a rotor (not shown) of a cutting apparatus (not shown), for example a robotic mower When the rotor is rotated sufficiently fast the cutting element 1 aligns itself radially outwards relative to a rotational axis of the rotor; the rotational axis is perpendicular to the plate plane of the main body 2. The pin is disposed in one of the rounded regions of the recess 4, each of which is formed by two rounded corners of the recess and forms a pivot bearing for rotating the cutting element 1 at and around the pin. The cutting element 1 is thus eccentrically mounted on the pin since the center of mass of the cutting element 1 is in the center of the recess 4, said recess therefore being formed symmetrically around the center of mass of the cutting element 1. If one of the two cutting bodies 3 collides with a stone during cutting of the grass stalks, 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 region of the recess 4. The cutting body 3 that collided with the stone is then positioned on the other side, i.e. passive for cutting, relative to the view selected in FIG. 1, while the other cutting body 3, which had faced away from the stone, now takes the position of the cutting body 3 that collided with the stone, i.e. is active for cutting.
[0057] It is particularly readily visible in FIG. 1 that the cutting bodies 3 are monolithically joined to the main body 2 without a material seam, i.e. are formed from the main body 2. The cutting body 3 and the main body 2 and therefore made of the same material.
[0058] FIG. 2 shows a representation of a cutting element 1′ according to a first embodiment. Similarly to the cutting element 1, the cutting element 1′ has a plate-shaped rectangular main body 2′. A wedge-shaped cutting body 3′ is secured to each of the opposite long sides of the main body 2′ by the action of an energy beam. However, it is also conceivable and also possible for the cutting bodies 3′ to be joined to the main body 2′ by soldering. In contrast to the cutting bodies 3 the cutting bodies 3′ are made of a sintered hardmetal and are accordingly hard and wear-resistant and are subsequently, i.e. after the sintering, joined to the main body 2′; the hard material particles are formed by tungsten carbide and the binder by cobalt. By contrast, the main body 2′ is made of steel, is therefore softer compared to the cutting bodies 3′ and therefore damps collision energy introduced into the cutting bodies 3′ by dissipation therein. The operating principle of the elongate recess 4′ formed in the main body 2′, whose long sides are arranged parallel to the sintered cutting bodies 3′ or the corresponding sides of the main body 2′ and whose rounded regions are connected to one another and act as a pivot bearing for the pin, is the same as that of the recess 4 from the prior art.
[0059] In FIG. 2 it is apparent that the cutting bodies 3′ each symmetrically narrow outwards in a wedge shape and thus form corresponding symmetrical cutting edges. The wedge angle of these is in each case less than 45°.
[0060] 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 main body 2″ differs from the recess 4″. The recess 4″ is round, as obtainable by a single drilled hole perpendicular to the plate plane of the main body 2″. Similarly to the recess 4″, where this comprises the two rounded regions, the recess 4″ serves as a pivot bearing in which the pin engages. Upon collision of one of the sintered cutting bodies 3″ with the stone the cutting element 1″ is rotated about the pin, as a result of which after a full revolution (360°) the collided sintered cutting body 3″ remains active for cutting. A change from the cutting body 3″ active for cutting to the cutting body 3″ previously passive for cutting on account of facing away from the stalk material can be realized by detaching the cutting element 1″ from the pin and then rotating it by 180° about a rotational axis oriented parallel to one of the long sides of the main body 2 and finally joining it to the pin so as to be freely rotatable in this position.
[0061] 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 main body 2′, namely diametrically to one another and equidistant to the center of mass of the cutting element 1′″, and in that sintered cutting bodies 3″ analogous to the sintered cutting bodies 3′ each asymmetrically narrow outwards in a wedge shape and thus form correspondingly asymmetric cutting edges. The wedge angle of these is in each case less than 45°.
[0062] The cutting element 1′″ can realize a change from a cutting body active for cutting 3″ to another cutting body 3″ previously passive for cutting similarly to the cutting element 1″, wherein the pin is engaged with the same recess 4″ before and after the change. Alternatively, the change can also be realized by detaching the cutting element 1′″ from the pin, rotating it by 180° about a rotational axis oriented perpendicular to the plate plane of the main body 2′ and thus inserting the pin into the other of the recesses 4″. The sintered cutting bodies 3″, which are made of the material of the cutting body 3′ and like these are joined to the main body 2′ by an atomic-level join, on account of their asymmetric shape each terminate flush with the main body 2′ at the side thereof shown in FIG. 4 so that the cutting element 1′″ can lie flat on the rotor even in the region of the sintered cutting bodies 3″.
[0063] FIG. 5 shows a representation of a cutting element 1″″ according to a fourth embodiment. The cutting element 1″″ has a trapezoidal main body 2″ which, like the main body 2′, is made of steel. On the sloping sides thereof, the sintered cutting bodies 3′ are joined to the main body 2″ by an atomic-level join similarly to the other embodiments. The sloping sides form a V-shape. The round recess 4″ is formed outside the center of mass of the cutting element 1″″, so that for the cutting element 1″″ too a centrifugal force-mediated alignment thereof radially outwards is effected upon rotation of the rotor. The change from the sintered cutting body 3′ active for cutting to a sintered cutting body 3′ which was previously passive for cutting and subsequently becomes active for cutting is realized similarly to cutting element 1″.
[0064] FIG. 6 shows a representation of a cutting element 1′″″ according to a fifth embodiment. In a departure from the cutting element 1″ this comprises a rectangular plate-shaped main body 2′″ having a plate-shaped narrower extension 5 thereof which is disposed outside the sides of the main body 2′″ at which the sintered cutting bodies 3′ are joined thereto by an atomic-level join; the main body 2′″ is made of the steel of the other embodiments. The change from a sintered cutting body 3′ active for cutting to a sintered cutting body 3′ which was previously passive for cutting and subsequently becomes active for cutting is realized similarly to the cutting element 1″. The round recess 4″ is formed outside the center of mass of the cutting element 1′″″, so that for the cutting element 1′″″ too a centrifugal force-mediated alignment thereof radially outwards is effected upon rotation of the rotor.
[0065] FIG. 7 shows a representation of a cutting element 1″″″ according to a sixth embodiment. A plate-shaped main body 2″″ of the cutting element 1″″″ is configured in the shape of a triangle with straight-cut corners. On the three main sides of the main body 2″″, pairs of which form a V-shape, altogether three of the sintered cutting bodies 3′ are joined to the main body 2″″ by an atomic-level join as in the other embodiments. Three of the round recesses 4″ are arranged symmetrically around the center of mass of the cutting element 1″″″. The change from a sintered cutting body 3′ which is active for cutting to a sintered cutting body 3′ which was previously passive for cutting and subsequently becomes active for cutting is realized by each recess 4″ as such similarly to cutting element 1″ and alternatively by changing from the recess 4″ that was originally engaged with the pin to another of the recesses 4″. Since each of the recesses is formed outside the center of mass of the cutting element 1′″″, the cutting element 1″″″ too experiences a centrifugal force-mediated alignment thereof radially outwards upon rotation of the rotor for each engagement in any of the recesses 4″.
[0066] FIG. 8 shows a representation of a cutting element 1′″″″ according to a seventh embodiment. The cutting element 1′″″″ differs from the cutting element 1″″″ only in that a recess 4′″ is formed in the main body 2″″ whose three corners are rounded and whose three sides have a convex curvature when viewed from inside from the recess 4″″. Each of the rounded corners acts as a pivot bearing for the pin similarly to recess 4″ and is arranged opposite one of the sintered cutting bodies 3′. In the case of a collision, where 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 the case of such a sliding motion in combination with a rotation about the pin one of the cutting bodies 3′ which was previously passive for cutting becomes active for cutting and vice versa similarly to recess 4″.
[0067] It is conceivable and also possible that only one of the cutting bodies 3′ or 3″ is sintered and formed by the hardmetal in the cutting elements 1′, 1″, 1′″, 1″″, 1′″″, 1″″″ and 1′″″″ represented in the FIGS. 2 to 8.
