Cutting system for a cutting apparatus

Abstract

The invention relates to a cutting system for a cutting apparatus of an agricultural machine, the cutting system comprising: a finger bar having mower fingers fastened thereon; and a knife having knife blades fastened to a knife bar; the knife being guided so as to move back and forth relative to the finger bar; the knife blades comprising a blade separation T; and the knife performing a back and forth movement with a stroke H.

Description

[0001] Cutting system for a cutting unit

[0002] The application relates to a cutting system for a cutting unit of an agricultural machine comprising a finger bar with mowing fingers attached thereto, wherein the mowing fingers are arranged at a distance A from one another, and a knife with knife blades attached to a knife rail, wherein the knife is guided back and forth relative to the finger bar, wherein the knife blades have a blade pitch T and wherein the knife executes a reciprocating movement with a stroke H.

[0003] US 6,510,681 B2 discloses a cutting system with knife blades mounted on a knife rail. Crescent-shaped guard fingers provide a cutting surface for the knives during horizontal reciprocating movement. According to one embodiment of the cutting system, a combination of a stroke of four and a half inches, a spacing of three inches between the guard fingers, and a spacing of two and a quarter inches between the knife blades is disclosed.

[0004] When cutting crops with such cutting systems, the knife blades first push the crop sideways to the next mower finger, where the counterblade is located to cut the crop. The combination of the blade pitch T, the blade stroke H, and the distance A between the mower fingers, among other factors, influences the performance of the cutting system.

[0005] One task may be to propose an improved cutting system with respect to the blade pitch T and the stroke H of the knife.

[0006] The object is solved by the subject matter of claim 1. Embodiments are specified in the subclaims.

[0007] The cutting system for a cutting unit of an agricultural machine comprises a finger bar with mowing fingers attached thereto and a knife with knife blades attached to a knife rail, wherein the knife is guided back and forth relative to the finger bar, wherein the knife blades have a blade pitch T and wherein the knife executes a back and forth movement with a stroke H. The stroke H corresponds to at least one and a half times, i.e. 1.5 times, the blade pitch T. The blade pitch T has a value between 58.5 millimeters and 63.5 millimeters.

[0008] The mowing fingers are each arranged at a distance A from each other. According to one embodiment, the distance A corresponds to the blade pitch T. The small distance A between the mowing fingers compared to the prior art reduces the achievable filling area related to the blade length, i.e. the area between the blades that can be filled with crop. Also related to the blade length, an increased number of cuts is made, as two cuts are made per stroke. Tests with different combinations of blade pitch T, stroke H of the blade and distance A between the mowing fingers have shown, with comparable load on a blade drive and comparable properties of the crop to be cut, that with a blade pitch T between 58.5 millimeters and 63.5 millimeters, particularly high driving speeds of the harvester can be achieved due to the increased performance of the cutting system.This results in an increased hectare output, i.e. the harvested area in hectares per hour, with a cutting unit of the same width, or in the possibility of achieving a comparable area output to that achieved with state-of-the-art systems using an attachment with a smaller working width.

[0009] According to one embodiment, the blade pitch T has a value of approximately 61 millimeters. This value corresponds to approximately 2.4 inches. Common cutting units are divided into segments, each five feet (5 ft) long in the longitudinal direction. 60 knife blades with a blade pitch T of 2.4 inches also advantageously extend over a longitudinal length of five feet.

[0010] The stroke H, for example, corresponds to 1.9 times to 2.1 times the blade pitch T. With a blade pitch of 2.4 inches, this corresponds to a stroke H between 115.8 millimeters and 128.0 millimeters. For example, the stroke H is 122.2 millimeters, or twice the blade pitch T. The theoretical value of twice the stroke H compared to the blade pitch T for a cutting system with double cutting per stroke is generally not required in practice, since the second cut per stroke is already completely completed as soon as a front end of the cutting edge has passed a corresponding counter cutting edge on the mowing finger.

[0011] According to a further embodiment, the blade pitch T has a value of approximately 61 millimeters. This value corresponds to approximately 2.4 inches. Tests have shown the highest hectare performance of the cutting unit with this blade pitch. According to a further embodiment, the blade pitch T has a value of approximately 60.0 millimeters.

[0012] According to a further embodiment, the knife has a mass M of less than 20 g / cm, in particular less than 18 g / cm, and particularly preferably approximately 15.85 g / cm, which corresponds to 1.07 pounds per foot (lb / ft), based on its length along a longitudinal axis. The mass of the knife includes the blades, the knife back, and the fastening elements for mounting the blades to the knife back. The connecting section or knife head provided for connection to the drive is not included in the mass M of the knife based on its length along the longitudinal axis.

[0013] The knife blades, for example, each have a center line, with the knife blades arranged next to each other along a longitudinal axis of the cutting system. The blade pitch T can be defined as the distance between the center lines of two adjacent knife blades. The center lines are orthogonal to the longitudinal axis and divide the knife blade into two halves. The mowing fingers can each have a fingertip, with the mowing fingers arranged next to each other along the longitudinal axis. The distance A can be defined as the distance between the fingertips. In the case of multiple blades, several blades are designed as a single piece, known as double blades or triple blades. Multiple blades have a center line per knife tip. The blade pitch T refers to the individual blades, not to the multiple blade as a whole. In the case of multiple mowing fingers, several mowing fingers are designed as a single piece, known as double fingers or triple fingers.Multiple mowing fingers have one fingertip per mowing finger. The distance A refers to the individual mowing fingers, not to the multiple mowing fingers as a whole. The distance A can correspond to the blade pitch T, whereby the mowing fingers can be provided in at least two variants with different finger lengths in the working direction.

[0014] According to a further embodiment, a drive drives the blade, with a speed of the drive being, for example, between 450 and 750 revolutions per minute, and with the blade performing one of the reciprocating movements with the stroke H for each rotation of the drive. The speed of the drive can be approximately 540 revolutions per minute, with the blade then performing approximately 1080 strokes per minute. Especially when cutting grass, the speed of the drive can be approximately 700 to 750 revolutions per minute.

[0015] According to a further embodiment, the load on the drive due to the centrifugal force of the blade at a drive speed of 540 revolutions per minute is less than or equal to the load on the drive due to the centrifugal force of a reference blade of a reference cutting system at a drive speed of 600 revolutions per minute. More generally, the drive speed can be 90 percent of the speed of the drive of the reference cutting system. With regard to properties that influence the load on the drive, the reference cutting system corresponds to the claimed cutting system, except for the following parameters of the reference cutting system:

[0016] - a blade pitch Tref of 76.2 millimeters or 3 inches,

[0017] - a stroke Href of 84.6 millimeters or 3.33 inches

[0018] - a mass Mref of the reference meter, relative to its length along the longitudinal axis, of at least 21 g / cm, in particular of 22.33 g / cm or 1.5 pounds per foot (lb / ft).

[0019] The drive load is to be understood as a theoretical load due to centrifugal force of the knife or the reference knife when idling, i.e. without any crop being cut and without taking friction into account. The reference cutting system corresponds to the claimed cutting system in all properties, except for the stated parameters and properties determined by the parameters. For example, the reference cutting system with a blade pitch Tref of 76.2 millimeters or 3 inches has a smaller number of blades for an identical cutting unit width. For a cutting unit segment 5 feet wide, the reference knife has 48 blades, while the knife of the claimed cutting system can have 60 blades. With regard to properties not related to the differing parameters, the reference cutting system corresponds to the claimed cutting system. For example, the drive kinematics used are identical.The load is related to the length of the knife in the longitudinal direction and for the reference knife, for example, is 3.73 N / cm or 113.69 Newton per foot (N / ft).

[0020] According to a further embodiment, the mowing fingers are made of sheet metal. The mowing finger can have a blade gap that forms counter-cutting edges for the knife blades. Compared to a forged finger, the mowing finger made of sheet metal with a blade gap eliminates the hold-down device. According to a further embodiment, the mowing fingers can be provided in at least two variants with different finger lengths in the working direction. The mowing fingers of the shorter variant or all mowing fingers can be open at the blade tip, whereby the blade tips can extend beyond the mowing finger.

[0021] The knife blades have a top side and a bottom side. A surface of the bottom side can be composed of a flat surface arranged in a plane and a recessed area extending above the plane, wherein a height of the knife blade corresponds to a maximum distance between the top side and the flat surface in a direction normal to the plane. A material thickness of the knife blade can be, at least in some regions, less than the height of the knife blade, wherein the material thickness of the knife blade corresponds to a distance between the top side and the bottom side. The knife blades can thus advantageously be manufactured with reduced mass while maintaining the same height of the knife blade.

[0022] According to a further embodiment, it is provided that the knife blades can be fastened to the knife rail both with the top side facing the knife rail and with the bottom side facing the knife rail

[0023] A surface of the upper side can, for example, be composed of an upper flat surface arranged in an upper plane and an upper side region extending outside the upper plane. The surface of the upper side adjacent to a rear edge of the respective knife blade can be formed at least partially by the upper flat surface. As a result, the surface of the upper side advantageously rests against the knife rail with a portion of the upper flat surface. The knife blades can be attached to the knife rail alternately with the upper side facing the knife rail and the underside facing the knife rail.

[0024] According to a further embodiment, the knife blades have a constant blade angle with a value between 20° and 27°. The blade angle corresponds to a half-angle of the angle formed by the blade tip. A perpendicular to the longitudinal axis in a plane of the knife blade and a straight line along a cutting edge of the knife blade enclose the blade angle. The blade angle is, for example, 21°. Furthermore, the knife blades can have a first constant blade angle in some sections and a second constant blade angle that differs from the first blade angle in some sections, wherein the transition between the sections can be discontinuous at a kink. Alternatively, the transition between the sections can be gradual, so that at least in the region of a transition section, a curved cutting edge without a constant blade angle results.

[0025] According to a further embodiment, the knife blades have two cutting bevels, one of the cutting bevels being arranged on the upper side and the other cutting bevel on the underside. The cutting bevels can, in particular, completely overlap in the region of a knife tip. Since the cutting bevels are arranged on different sides of the knife blade, the overlap is made possible. The overlap advantageously results in a narrower knife tip and, with the same blade angle, a greater length of the cutting section in the working direction of the knife blade. The knife can have knife blades in at least two variants with different lengths of the cutting section in the working direction and / or different blade angles. Exemplary embodiments are described below with reference to the accompanying drawings. The statements do not limit the general concept of the invention.

[0026] It shows

[0027] Figure 1 is a partial view of a cutting system according to an embodiment;

[0028] Figure 2 is a side view of the cutting system according to Figure 1;

[0029] Figure 3 is a partial view of a knife of the cutting system according to Figure 1;

[0030] Figure 4 is a partial view of a cutting system according to another embodiment;

[0031] Figure 5 is a partial view of a knife of the cutting system according to Figure 4;

[0032] Figure 6 is a partial view of a non-claimed reference cutting system;

[0033] Figures 7 to 11 show a knife blade for the cutting system in different views;

[0034] Figures 12 and 13 show a variant of the knife blade in different views;

[0035] Figures 14 and 15 show another variant of the knife blade in different views;

[0036] Figures 16 to 18 show another variant of the knife blade in different views;

[0037] Figure 19 is a comparative illustration of variants of the knife blades according to Figures 12, 14 and 16;

[0038] Figure 20 is a diagram comparing achievable travel speeds with the knife blade variants shown in Figure 19; Figure 21 is another diagram comparing achievable travel speeds with the knife blade variants shown in Figure 19.

[0039] Figure 1 shows an embodiment of a cutting system for a cutting unit of an agricultural machine in a schematic partial representation. Figure 2 shows the cutting unit in a side view. Figure 3 shows a detail of a blade 14 of the cutting unit. Figures 1 to 3 are described together below. The cutting system comprises a finger bar 19 with mowing fingers 18 attached thereto, wherein the mowing fingers 18 are each arranged at a distance A from one another, and the blade 14 with knife blades 10 attached to a knife rail 22, wherein the knife 14 is guided back and forth relative to the finger bar 19, wherein the knife blades 10 have a blade pitch T and wherein the knife 14 executes a reciprocating movement with a stroke H. The distance A can correspond to the blade pitch T, while the stroke H corresponds approximately to twice the blade pitch T, which can also be referred to as a double stroke.The blade pitch T has a value between 58.5 millimeters and 63.5 millimeters.

[0040] The knife blades 10 each have a knife tip 11, wherein the knife blades 10 are arranged next to one another along a longitudinal axis L. The blade pitch T is defined as a distance between center lines C of two adjacent knife blades 10 that are orthogonal to the longitudinal axis L, see Figure 5. The mowing fingers 18 each have a fingertip 20, wherein the mowing fingers 18 are arranged next to one another along the longitudinal axis L and wherein the distance A is defined as a distance between the fingertips. A drive 21 can drive the knife 14, wherein a speed of the drive 21 is between 450 and 750 revolutions per minute and wherein the knife 14 executes one of the reciprocating movements with the stroke H for each revolution of the drive. The speed of the drive 21 can be, for example, 540 revolutions per minute.

[0041] The knife 14 comprises, for example, a knife rail 22, which is also referred to below as the knife back 22. A plurality of knife blades 10 are fastened to the knife rail 22. The knife blades 10 are arranged and fastened to the knife back 22 next to one another along the longitudinal axis L. The knife back 22 is connected to a connecting section 25. The connecting section 25 serves to couple the knife 14 to the knife drive 21 for moving the knife 14 back and forth along the longitudinal axis L. The knife blades 10 can each be connected to the knife back 22 via one and / or more fastening elements 26, such as screws and / or nuts. Other possibilities for fastening the knife 14 are known to those skilled in the art.

[0042] The knife blades 10 each have a cutting section 27 and a fastening area 9 with a rear edge 8, which are arranged successively along a working direction P. A working direction P is oriented perpendicular to the longitudinal axis L and corresponds, for example, to a direction of travel of an agricultural machine. Viewed in the working direction P, the cutting sections 27 of the knife blades 10 protrude forward from the knife back 22. The knife blades 10 are each arranged in contact with the knife back 22 via the fastening area 9. The rear edges 8 of the knife blades 10 can protrude rearward beyond the knife back 22 in the working direction P. Cutting edges 3 are formed on the cutting section 27 of the respective knife blade 10 and are aligned at an angle to one another such that they taper to a point in the working direction P.A straight line along the cutting edge 3 encloses a constant blade angle K between 20 degrees and 27 degrees, in particular of approximately 21 degrees, with the working direction P.

[0043] In the illustrated embodiment, the knife blades 10 are all aligned identically, namely with a bottom side 2 facing the knife spine 22. All top sides 1 of the knife blades 10 face away from the knife spine 22.

[0044] Figure 4 shows a schematic partial view of the cutting system according to a further embodiment. Figure 5 shows the knife 14 of the cutting system according to Figure 4. Figures 4 and 5 are described together. In Figure 5, the blade pitch T is indicated as the distance between the center lines C, orthogonal to the longitudinal axis L, of two adjacent knife blades 10. The structure largely corresponds to the embodiment according to Figure 1 and will not be described again. Identical components are provided with identical reference numerals. The embodiment shown differs in the arrangement of the knife blades 10. These are arranged alternately on the knife back 22. The top side 1 and the bottom side 2 alternately face the knife back 22.

[0045] Figure 6 schematically shows a reference cutting system that is not under stress. The reference cutting system corresponds to the stressed cutting system in terms of properties that influence the drive load, except for the following parameters of the reference cutting system:

[0046] - a blade pitch Tref of 76.2 millimeters or 3 inches,

[0047] - a stroke Href of 84.6 millimeters or 3.33 inches and

[0048] - a mass Mref of the reference meter, relative to its length along the longitudinal axis, of at least 21 g / cm, in particular of 22.33 g / cm or 1.5 pounds per foot (lb / ft).

[0049] The reference cutting system corresponds to the claimed cutting system in all properties, except for the stated parameters and properties determined by the parameters. For example, the reference cutting system with a blade pitch Tref of 76.2 millimeters or 3 inches has a smaller number of blades while maintaining the same cutting unit width. For a cutting unit segment 5 feet wide, the reference blade has 48 blades, while the blade of the claimed cutting system can have 60 blades. With respect to properties unrelated to the differing parameters, the reference cutting system corresponds to the claimed cutting system. For example, the drive kinematics not shown here are identical.

[0050] A load on the drive 21 of the embodiments according to Figures 1 and 4 due to a centrifugal force of the respective knife 14 is less than or equal to the load on the drive due to the centrifugal force of a reference knife 14' of the reference cutting system according to Figure 6 at a drive speed of 600 revolutions per minute. Figures 7 to 11 show another exemplary knife blade 10 in various views. Figure 7 shows the knife blade 10 in a view of an upper side 1. Figure 8 shows the knife blade from Figure 3 in a side view rotated by 90 degrees, in which the position of the knife tip 11 from the front and the trailing edge 8 at the rear, as well as the overall flat shape of the knife blade 10 with the upper side 1 and a lower side 2 can be seen. Figure 9 shows a section along the line AA from Figure 7 at a double magnification.Figure 10 shows a view of the underside 2 of the knife blade 10 and Figure 11 shows a view of the rear edge 8 rotated by 90 degrees compared to Figure 7 in an enlarged representation.

[0051] Figures 7 to 11 are referred to together below. The knife blade 10 has two cutting edges 3 for cutting crop material, each of which has an outer edge forming a cutting edge. At the knife tip 11, which in the exemplary embodiment is rather blunt, the cutting edges 3 converge approximately and thus form the approximately triangular shape of the front part of the knife blade 10. This part of the knife blade 10 has an approximately triangular recess 5 with a surrounding edge region 7. The direction of movement of the knife 14 with the knife blade 10 for cutting the crop material is transverse to the working direction P (Figure 2), in particular approximately at right angles thereto, and in the installed position horizontal or slightly angled, which corresponds to the plane of the drawing in Figure 3. The approximately triangular cutting edge section 27 of the knife blade 10 is adjoined by the fastening region 9, which is approximately rectangular in view and terminates at the rear edge 8.The fastening area 9 has fastening means 17 for mounting the knife blade 10, which is mounted on the knife bar (22, Figure 1).

[0052] The surface of the underside 2 is composed of a flat surface 4 arranged in the plane E (cf. Figure 7) and the recess region 6 extending above the plane E, as can be seen in Figures 5 and 6. The height Z of the knife blade 10 corresponds to the maximum distance between the upper side 1 and the flat surface 4 in a normal direction N to the plane E, as shown in Figure 7. A surface of the upper side 1 is in turn composed of an upper flat surface 15 arranged in an upper plane OE (Figure 7) and an upper side region 16 extending outside the upper plane OE. The material thickness M of the knife blade 10 corresponds to the distance between the upper side

[0053] 1 and the underside 2, which is measured in the normal direction N. The material thickness M of the knife blade 10 is, at least in some areas, less than the height Z of the knife blade 10, as shown by way of example using a measuring point in Figure 20. The lower plane E and the upper plane OE are preferably aligned parallel to one another and spaced from one another by the height Z of the knife blade 10.

[0054] The flat surface 4 can be a surface whose planarity, also referred to as planarity, is greater than that of the recess region 6. Any points on the flat surface 4 are thus spatially arranged in the plane E. The recess region 6 also forms a surface that can be more uneven in comparison, i.e. curved or arched, so that points on the surface of the recess region 6 are spatially arranged in different planes. The flat surface 4 comprises a plurality of partial surfaces. In the area of ​​the cutting edges 3 of the knife blade, the surface of the underside 2 has a partial surface 4A of the flat surface 4. On the surface of the underside

[0055] 2, wear marks 12 for determining wear on the cutting edge can be arranged directly on the partial surface 4A arranged in the region of the cutting edges 3. A further partial surface 4B of the flat surface 4 of the surface of the underside 2 is arranged around the recess 5, in the edge region 7 of the recess 5. A plurality of partial surfaces 4C of the flat surface 4 are arranged on the surface of the underside 2 at the rear edge 8 of the knife blade. Finally, a partial surface 4D of the flat surface 4 is arranged in the fastening region 9.

[0056] Preferably, a plurality of upper partial surfaces 15C of the upper planar surface 15 are arranged on the trailing edge 8 of the knife blade on the surface of the upper side 1, wherein the upper partial surfaces 15C are each arranged opposite the recess region 6 at the trailing edge 8 on the underside 2. The upper partial surfaces 15C are each interrupted along the trailing edge 8 by the upper side region 16, wherein the partial surfaces 4C on the underside 2 are each opposite the upper side region 16, so that the upper partial surfaces 15C are arranged along the trailing edge 8 alternating with the partial surfaces 4C on the underside 2. This allows the knife blade 10 to be mounted both with the underside 2 facing the knife bar (22, Figure 2) and with the upper side 1 facing the knife bar.The reduced area at the rear edge 8, which results from the wave shape visible in Figure 7, also advantageously reduces the friction with respect to guide elements (not shown) supporting the knife blade 10 to the rear.

[0057] In Figures 12 and 13, which are described together, a variant of the knife blade 10 is shown in a side view and in a perspective view. The representation is schematic and serves to explain embodiments of the cutting edges 3. Features of the surfaces and the trailing edge, as shown in Figures 7 to 11, are not shown here, but can be combined with the features described below. The knife blade 10 according to Figures 12 and 13 has the cutting section 27 with two cutting edges 3 and the fastening area 9 with holes as fastening means 17. A cutting bevel 28 of each cutting edge 3 is arranged only on the upper side 1. The cutting bevels 28 form the cutting edge on the outer edge with the underside 2 of the knife blade. The blade constant blade angle K is between 20 degrees and 27 degrees.

[0058] In Figures 14 and 15, which are described together, a further variant of the knife blade 10 is shown in a side view and in a perspective view. Features of the surfaces and the trailing edge, as shown in Figures 7 to 11, are not shown here, but can be combined with the features described below. The knife blade 10 according to Figures 14 and 15 has the cutting section 27 with two cutting edges 3 and the fastening area 9 with holes as fastening means 17. The cutting bevels 28 of the cutting edges 3 are arranged only on the upper side 1 of the knife blade 10 and each have a kink 29. The cutting bevels 28 form the cutting edge at the outer edge with the underside 2 of the knife blade. A first constant blade angle K1 of, for example, 21 degrees is less acute than a second constant blade angle K2 of, for example, 15 degrees.

[0059] In Figures 16 to 18, which are described together, a further variant of the knife blade 10 is shown in a side view and in a perspective view. Features of the surfaces and the trailing edge, as shown in Figures 7 to 11, are not shown here, but can be combined with the features described below. The knife blade 10 according to Figures 14 and 15 has the cutting section 27 with two cutting edges 3 and the fastening area 9 with holes as fastening means 17. One of the cutting bevels 28 is arranged on the upper side 1 of the knife blade 10 and forms the cutting edge at the outer edge with the underside 2 of the knife blade 10, while the other cutting bevel 28 is arranged on the underside 2 of the knife blade 10 and forms the cutting edge at the outer edge with the upper side 1 of the knife blade 10. The two cutting edges are thus arranged offset in the normal direction in different planes.The at least partial overlap of the cutting bevels 28 in the area of ​​the knife tip 11 advantageously enables a narrower knife tip 11 than in the knife blade 10 according to Figure 12. The blade angle K is approximately 21 degrees, although this does not limit the exemplary embodiment. Preferably, the knife blade 10 has a constant blade angle K between 20 degrees and 27 degrees.

[0060] Figure 19 shows a comparative illustration of variants of knife blades 10. The knife blade designated 10A has a blade angle K of 21 degrees and a blade pitch T of two inches, which corresponds to the extension of the knife blade in the longitudinal direction L (see Figure 5). The knife blade 10A cannot be used with the cutting mechanism according to the invention. 10B designates the knife blade according to Figure 12, which has a blade angle K of 21 degrees and a blade pitch T of 2.4 inches. A length LP of the cutting section 27 in the working direction P is greater for the knife blade 10B than for the knife blade 10A, with the same blade angle K. 10D designates the knife blade according to Figure 16, which has a blade angle K of 21 degrees and a blade pitch T of 2.4 inches.Due to the overlap of the cutting bevels 28 in the area of ​​the knife tip 11, the length LP of the cutting section 27 in the working direction P is greater for the knife blade 10D than for the knife blade 10B, given the same blade angle K. 10C denotes the knife blade according to Figure 14, which has a first blade angle K1 of 21 degrees and a second blade angle K2 of 15 degrees. The blade pitch T is 2.4 inches. Due to the more acute blade angle K2, the length LP of the cutting section 27 in the working direction P is greater than for the knife blades 10B and 10D. The more acute second blade angle K2 leads to less favorable cutting behavior of the knife blade 10C in this area.

[0061] Figure 20 shows a diagram comparing achievable travel speeds with the knife blade variants shown in Figure 19. The stroke H is given in millimeters on the abscissa 30. The achievable travel speed of a harvester is given dimensionlessly on the ordinate 31. Curves 32, 33, 34, and 35 show that the achievable travel speed increases degressively with the stroke H, with the extent of the respective curve depending on the number of cuts per stroke and the shape of the blade. To make different blade shapes comparable, the load on the drive by the centrifugal force of the knife was standardized.

[0062] The curve 32 represented by dots represents the relationship between travel speed and stroke H with one cut per stroke. Point 36 in the curve 32 designates the achievable travel speed with a frequently used knife blade of a single-cutting reference cutting unit with a 3-inch blade pitch and a blade angle of 30 degrees with a stroke H of approximately 3.33 inches or 84.6 millimeters, which cannot be used with the claimed cutting system, but for example with the reference cutting system according to Figure 6. The achievable travel speed of the reference cutting unit is 100 percent.

[0063] Curve 33, shown with short lines, represents the relationship between travel speed and stroke H with two cuts per stroke. Point 37 on curve 33 designates the achievable travel speed of 162 percent of the reference cutting unit with a frequently used knife blade with a 2-inch blade pitch and a blade angle K of 21 degrees and a stroke H of 4 inches or 101.6 millimeters, which is mentioned as a comparison example and cannot be used with the claimed cutting system. Point 38 on curve 33 designates the achievable travel speed of 182 percent with the knife blade 10B according to Figures 12 and 19, which can be used with the claimed cutting system. The knife blade 10B has a blade pitch T of 2.4 inches and a blade angle K of 21 degrees and a stroke H of 4.8 inches or 121.9 millimeters.If the stroke H is in practice less than twice the blade pitch, the achievable travel speed is correspondingly lower on curve 33.

[0064] The curve 34, represented by long dashes and dots, represents the relationship between travel speed and stroke H for two cuts per stroke. Point 39 on curve 34 designates the achievable travel speed of 210 percent with the knife blade 10C usable with the claimed cutting system according to Figures 14 and 19, with a 2.4 inch blade pitch, a first blade angle K1 of 21 degrees and a second blade angle K2 of 15 degrees with a stroke H of 4.8 inches or 121.9 millimeters. If the stroke H is less than twice the blade pitch in practice, the achievable travel speed is correspondingly lower on curve 34.

[0065] Curve 35, represented by medium-length lines, represents the relationship between travel speed and stroke H for two cuts per stroke. Point 40 on curve 35 indicates the achievable travel speed of 196 percent of the knife blade 10D usable with the claimed cutting system according to Figures 16 and 19, with a 2.4-inch blade pitch and a blade angle of 21 degrees and a stroke H of 4.8 inches or 121.9 millimeters. The achievable travel speed is lower than with knife blade 10C, whose acute blade angle K2 of 15 degrees, however, leads to poorer cutting performance. If the stroke H is less than twice the blade pitch in practice, the achievable travel speed is correspondingly lower on curve 35.

[0066] Figure 21 shows a further diagram comparing the achievable travel speeds with the knife blade variants according to Figure 19. The stroke H is given in millimeters on the abscissa 30', whereby the respective strokes H are identical to those in Figure 20. The ordinate 31' indicates an achievable travel speed without dimensions. The load on the drive is the same for all variants shown, so that a relative comparison is possible. For the curves 33', 34' and 35' of the knife blades according to Figure 19, a mass reduction of 30 percent has been taken into account compared to the corresponding curves 33, 34, 35 in Figure 20. The curve 32 of the reference system is unchanged. Point 36 in the curve 32 indicates the achievable travel speed of the single-cutting reference cutting system of 100 percent.

[0067] Point 37' on curve 33' indicates the achievable travel speed of 195 percent with the knife blade 10A according to Figure 19, which cannot be used with the claimed cutting system, taking into account the 30 percent mass reduction with otherwise identical parameters. Point 38' on curve 33' indicates the achievable travel speed of 217 percent with the knife blade 10B according to Figures 12 and 19, taking into account the 30 percent mass reduction with otherwise identical parameters. Point 39' on curve 34' indicates the achievable travel speed of 251 percent with the knife blade 10C according to Figures 14 and 19, taking into account the 30 percent mass reduction with otherwise identical parameters.Point 40' on curve 35' indicates the achievable travel speed of 234 percent of the knife blade 10D according to Figures 16 and 19, taking into account the 30 percent mass reduction with otherwise identical parameters. If the stroke H is less than twice the blade pitch T in practice, the achievable travel speed is correspondingly lower on the respective curves 33', 34', and 35'.

[0068] List of reference symbols

[0069] 1 top

[0070] 2 Bottom

[0071] 3 cutting edges

[0072] 4 Plane surface

[0073] 4A Partial areas of the plan area

[0074] 4B Partial areas of the plan surface

[0075] 4C Partial areas of the plan surface

[0076] 4D sub-areas of the plan surface

[0077] 5 recesses

[0078] 6 Recess area

[0079] 7 Edge area of ​​the recess

[0080] 8 Rear edge of the knife blade

[0081] 9 Mounting area

[0082] 10 knife blades

[0083] 11 knife tips

[0084] 12 wear marks

[0085] 14 knives

[0086] 14' reference meter

[0087] 15 Upper plan surface

[0088] 15C Upper partial surfaces of the upper plane surface at the trailing edge

[0089] 16 Top area

[0090] 17 Fasteners, hole

[0091] 18 mowing fingers

[0092] 19 finger bars

[0093] 20 fingertips

[0094] 21 Drive

[0095] 22 Knife rail, knife back 25 Connecting section

[0096] 26 Fastener, screw, nut

[0097] 27 Cutting section

[0098] 28 cutting bevel

[0099] 29 kink

[0100] 30, 30' abscissas

[0101] 31 , 31 ' ordinates

[0102] 32-35 Curve profiles

[0103] 33'-35' curves

[0104] 36-40 points

[0105] 37'-40' points

[0106] L Longitudinal axis

[0107] H Hub

[0108] T division

[0109] A distance

[0110] C Center line

[0111] Href Reference Hub

[0112] Tref reference division

[0113] Aref reference distance

[0114] OE Upper Level

[0115] E Level

[0116] N Normal direction

[0117] Z Height of the knife blade

[0118] P Working direction

[0119] M material thickness

[0120] K Blade angle

[0121] K1 First blade angle

[0122] K2 Second blade angle

[0123] LP Length of the cutting section in working direction

Claims

Cutting system for a cutting unit Claims 1 . Cutting system for a cutting unit of an agricultural machine, comprising a finger bar (19) with mowing fingers (18) attached thereto; a knife (14) with knife blades (10) attached to a knife rail (22), wherein the knife is guided back and forth relative to the finger bar, wherein the knife blades have a blade pitch T and wherein the knife executes a back and forth movement with a stroke H, wherein the stroke H corresponds to at least one and a half times the blade pitch T and wherein the blade pitch T has a value between 58.5 millimeters and 63.5 millimeters.

2. Cutting system according to claim 1, characterized in that the blade pitch T has a value of 61 millimeters or 2.4 inches, the stroke H being greater than the blade pitch T by a factor of between 1.9 and 2.

1.

3. Cutting system according to one of the preceding claims, characterized in that the knife has a mass M of less than 20 g / cm, in particular less than 18 g / cm and particularly preferably less than 16 g / cm, based on its length along a longitudinal axis (L).

4. Cutting system according to one of the preceding claims, characterized in that the knife blades (10) each have a center line (C), wherein the knife blades are arranged next to one another along a longitudinal axis (L) of the cutting system, wherein the blade pitch T is defined as a distance between the center lines of adjacent knife blades.

5. Cutting system according to claim 4, characterized in that the mowing fingers (18) each have a fingertip (20), wherein the mowing fingers are arranged next to one another along the longitudinal axis (L), wherein the mowing fingers are each arranged at a distance A from one another, wherein the distance A is defined as a distance between the fingertips, wherein the distance A corresponds in particular to the blade pitch T, and wherein the mowing fingers are provided in at least two variants of different finger lengths in the working direction.

6. Cutting system according to one of the preceding claims, characterized in that a drive (21) drives the knife (14), wherein a speed of the drive is between 450 and 750 revolutions per minute and wherein the knife executes a reciprocating movement with the stroke H for each revolution of the drive.

7. Cutting system according to claim 6, characterized in that a load on the drive (21) by a centrifugal force of the blade (14) at a speed of the drive of 90 percent of a speed of a drive of a reference cutting system is less than or equal to the load on the drive (21) by the centrifugal force of a reference blade of the reference cutting system, wherein the reference cutting system corresponds to the cutting system with respect to properties that influence the load on the drive, except for the following parameters of the reference cutting system: - a blade pitch Tref of 76.2 millimeters or 3 inches, - a stroke Href of 84.6 millimeters or 3.33 inches, - a mass Mref of the reference meter, referred to its length along the longitudinal axis (L), of at least 21 g / cm, in particular of 22.33 g / cm or 1.5 lb / ft.

8. Cutting system according to one of the preceding claims, characterized in that the knife blades (10) have an upper side (1) and a lower side (2), wherein the knife blades are mounted on the knife rail (22) both with the upper side facing the knife rail and with the can be fastened with the underside facing the knife rail, wherein the knife blades (10) are fastened to the knife rail (22), in particular alternately with the top side (1) facing the knife rail (22) and the underside (2) facing the knife rail.

9. Cutting system according to claim 8, characterized in that a surface of the underside (2) is composed of a flat surface (4) arranged in a plane (E) and a recess region (6) extending above the plane, wherein a height of the knife blade (10) corresponds to a maximum distance (Z) between the upper side and the flat surface in a normal direction (N) to the plane.

10. Cutting system according to claim 9, characterized in that a material thickness of the knife blade (10) is at least partially less than the height (H) of the knife blade, wherein the material thickness of the knife blade corresponds to a distance between the upper side (1) and the lower side (2).

11. Cutting system according to one of the preceding claims, characterized in that the knife blades (10) have a constant blade angle (K), wherein the blade angle (K) has a value between 20° and 27°.

12. Cutting system according to claim 11, characterized in that the blade angle (K) has a value of approximately 21 °.

13. Cutting system according to one of the preceding claims, characterized in that the knife blades (10) have, in sections, a first constant blade angle (K1) and, in sections, a second constant blade angle (K2) different from the first blade angle (K1).

14. Cutting system according to one of the preceding claims, characterized in that the knife blades (10) have an upper side (1) and a lower side (2), wherein two cutting bevels (28) are provided and wherein one of the cutting bevels is arranged on the top side and the other cutting bevel is arranged on the bottom side.

15. Cutting system according to claim 14, characterized in that the cutting bevels (28) completely overlap in the region of a knife tip (11).

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