Patent Application
20190269061
This document relates to a disc tool for an agricultural implement, to an agricultural implement comprising such a disc tool, and to a method for manufacturing such a disc tool.
The disc tool is of the type that is specially suited to breaking up field residues, for example from oil-yielding plants, but also from maize or other crops, and that provides working depths of down to ca. 10 cm.
It is known to cultivate soil with the aid of disc tools in order to achieve different types of soil improvement. For some types of crops, it is desirable to carry out relatively shallow soil cultivation, about 1-3 cm, while plant residues situated on the soil surface are chopped up, ground or mechanically crushed in some other way.
Such soil cultivation is normally sought across the full width of the agricultural implement, i.e. not only sideways from mutually separate tracks.
Particularly in the cultivation of rape, it is desirable to crush rape plant residues, including stalks and seed capsules, in order to reduce the risk of diseases.
A known disc tool of this kind is disclosed in SE537123 C2. This tool has protruding parts which extend radially out toward the periphery and which have cutting edges extending 15-75 degrees relative to the plane of the disc tool.
In some circumstances, the disc tool disclosed in SE537123 C2 can accumulate plant residues, such as straw and weeds, which means that the cultivation has to be interrupted in order for the tools to be cleaned.
There is a need for tools that can satisfy the same function but have less need of cleaning and can at the same time be manufactured at low cost.
It is therefore an object to make available an improved disc tool for breaking up field residues.
The invention is defined by the accompanying independent claims. Embodiments are set out in the dependent claims, in the following description and in the accompanying drawings.
According to a first aspect, a disc tool is made available for breaking up field residues, comprising a central hub portion, which is designed for mounting the disc in a tool holder in order to make the disc rotatable about a rotation axis, and a cultivating portion, which is located radially outside of and adjoins the hub portion. The cultivating portion moreover comprises a plurality of substantially straight cutting edges which are located at the periphery of the disc tool. The cultivating portion has a plurality of undulations which, with an axial extent decreasing toward the inside, run from the cutting edges to the hub portion. The cutting edge is designed such that 90-98% of a track formed by the cutting edge consists of straight track portions.
Here, “track” signifies the track that is formed by the actual disc tool when it rolls with its rotation axis substantially at right angles to the ground. It will be appreciated that, depending on the design involved, such a track can consist either of straight portions interrupted by curved portions or of straight portions interrupted by an absence of tracks.
The expression “substantially straight” means that the cutting edges are straight when viewed in at least one plane.
When dimensions are given as angles in relation to a central angle, this signifies an angle taken at the center of the disc tool.
The radial direction is a direction from the center of the disc tool and at right angles to the rotation axis of the disc tool.
The axial direction is parallel to the rotation axis of the disc tool.
The circumferential direction is a direction that follows the periphery of the disc tool.
A direction of travel is the direction that the agricultural implement normally follows when in use.
A disc tool according to what has been described above has been found to be very good at breaking up field residues, while at the same time being able to be manufactured at low cost and having a reduced tendency to accumulate field residues.
The disc tool, viewed in a circumferential direction at the periphery of the disc tool, can have adjacent cutting edges at an angle to each other of up to 75°-115°, preferably 85°-115°, 95°-105° or 100°-105°.
The disc tool can further comprise a recess which extends radially inward from the periphery and which is located at an imaginary intersection between two cutting edges.
The recess can extend radially inward by a distance corresponding to 10-60% of a radius of the disc.
The recess can extend corresponding to a central angle of up to 1°-25°, preferably 2°-15° or 2°-10°.
The cutting edges, viewed along the periphery, can have angles alternating, by the same amount +/−5°, with respect to the hub portion.
The cutting edges can have an angle of up to 30°-55° relative to a plane which is at right angles to the rotation axis of the disc tool, preferably 30°-50° or 35°-45°.
The cutting edges can be beveled, such that each cutting edge has a material thickness that decreases outward to the edge.
A plane which is at right angles to the rotation axis can be defined by a transition portion where the radially outer portion of the hub portion meets the radially inner portion of the cultivating portion, and the cultivating portion can be located 30-70% on one axial side of said plane and 70-30% on the other axial side of said plane.
The undulations can, at the periphery of the disc tool, have an axial extent of up to 8-18 cm, preferably 8-15 cm or 9-12 cm.
According to a second aspect, an agricultural implement for soil cultivation is made available, comprising a plurality of disc tools according to what has been described above.
The disc tools can be arranged such that the rotation axis, i.e. the rotation axis of the respective disc tool, has an angle of 70°-80° relative to a direction of travel.
The rotation axes of the disc tools can be mutually parallel but not coincident.
The disc tools can be arranged along first and second transverse rows, wherein the disc tools on a respective row are arranged at substantially the same distance from each other and with parallel rotation axes, and wherein the disc tools on one of the rows are offset sideways by a distance of up to 80-120% of said mutual distance relative to the disc tools on a second of the rows.
Said mutual distance can be 80-120% of the axial extent of one of the disc tools, preferably 90-110% or 95-105%.
The rotation axes of the disc tools of the first row can be non-parallel to the rotation axes of the disc tools of the second row.
The rotation axes of the two rows preferably have angles of the same amount with respect to the direction of travel.
A third aspect concerns a use of the agricultural implement according to what has been described above for breaking up field residues, the disc tools providing an average working depth of less than 10 cm, preferably less than 5 cm.
A fourth aspect concerns a method for manufacturing a disc tool for soil cultivation, which method comprises cutting a plane disc blank of metal to a substantially circular or polygonal shape, formation of a plurality of cutting edges along a periphery of the cut disc blank, and compression-molding of the cut disc blank such that a plurality of undulations are obtained which, with an axial extent decreasing toward the inside, run from the cutting edges to a central portion of the disc tool, and such that 90-98% of a track formed by the cutting edge consists of straight track portions.
The method can be carried out such that the resulting disc tool, viewed in a circumferential direction at the periphery of the disc tool, has adjacent cutting edges at an angle to each other of up to 75°-105°, preferably 80°-100° or 85°-95°.
The method can further comprise forming radial recesses which extend inward from the periphery and where adjacent cutting edges are to meet.
The method can further comprise heating the disc blank in conjunction with said compression molding.
The disc blank can be cut so as to form a circular disc blank.
Alternatively, the disc blank can be cut so as to form an equilateral polygon with 5-12 sides.
In such a polygon, two cutting edges can be formed for each side of the polygon.
Alternatively, one cutting edge can be formed for each side of the polygon.
The hub portion 10 can comprise a plane portion, which surrounds a fastening arrangement and of which the radially outermost portion adjoins the cultivating portion 11.
The cultivating portion 11 comprises a plurality of undulations 111, 112, which have an amplitude decreasing toward the hub portion 10. Specifically, the amplitude can decrease linearly in the direction toward the hub portion 10.
At the radially outermost portion of the cultivating portion 11 there is a cutting edge E1, E2, which can be formed by chamfering or grinding the piece of material from which the disc tool 1 is formed.
The cutting edge E1, E2 is configured such that most of its length, preferably at least 90% of its length, consists of straight portions E1, E2. These straight portions E1, E2 can be separated by curved portions, as is shown in
Here, “straight portions” means portions which are straight when viewed in at least one plane.
Specifically, the straight portions shown in
The straight portions have an angle of up to 30°-55° relative to a plane P which is at right angles to the rotation axis of the disc tool, preferably 30°-50°. The angle can most preferably be 35°-45°.
In the examples shown, the cutting edges of the disc tool, viewed along the periphery, can have angles alternating, by the same amount +/−5°, with respect to the plane P.
Each pair of adjacent straight portions E1, E2 has a mutual angle of up to 75°-115°, preferably 85°-115°, 95°-105° or 100°-105°. As will be seen, the angle between each pair of adjacent straight portions E1, E2 is about 90°.
The cutting edges E1, E2 can have a maximum axial amplitude of about 8-18 cm, preferably 8-15 cm. Specifically, the amplitude can be 9-12 cm.
Moreover, the cultivating portion 11 can be located 40-60% on one axial side of said plane P and 60-40% on the other axial side of the plane P.
The disc tool 1 in
The disc blank 1′, and the resulting disc tool 1, can have a diameter of up to about 400-700 mm.
Specifically, the tool shown in
The compression molding can proceed such that the disc blank 1′ is heated and is then pressed by a pair of tools comprising an upper part and a lower part, where undulations oriented in one axial direction are formed along a respective edge of one tool part and undulations oriented in another direction are formed along a respective edge of the other tool part.
The hub portion 20 may be identical to the hub portion 10 shown in
In the tool in
However, the cutting edges E1, E2 of the tool in
The recess 213, 214 can extend radially inward by a distance corresponding to 10-30% of a radius of the disc tool 2, preferably of a maximum radius of the disc tool 2.
The recess 213, 214 means that the stretching of the material that takes place at its outermost portion during the shaping of the disc tool 2 from the plane disc blank 2′ can be reduced, which means that it is possible to reduce the risk of cracks forming and of the finished disc tool 2 breaking.
The recess 213, 214 can extend corresponding to a central angle of up to 1°-25°, preferably 2°-15° or 2°-10°.
The disc tool 2 shown in
Recesses 213 between cutting edges E1, E2 that are formed from different sides of the pentagon can be larger than recesses 214 between cutting edges that are formed from one and the same side of the pentagon.
The hub portion 30 may be identical to the hub portions 10, 20 shown in
In the tool 3 in
In the tool 3 shown in
Moreover, the recesses 313 can extend over a central angle which is less than in the disc tool 2 in
The disc tool shown in
The disc blank 3′, and the resulting disc tool 3, can have a maximum crosswise dimension (corresponding to a diameter) of up to about 400-700 mm.
The cutting edges E1, E2 of the tool 3 in
As will be seen from
A plurality of such arms 101 can be arranged along a transverse beam 102 of the agricultural implement 100. The arms 101 are preferably arranged at substantially the same distance from one another and are distributed uniformly along at least 90% of the length of the beam 102.
Each disc tool 1 can be rotatable about an axis Ar, which can have an angle of up to 15°-20°, typically 17°, relative to the longitudinal direction of the beam 102. In the example shown, all of the disc tools 1 on one beam are arranged in the same direction and with parallel rotation axes Ar.
As will be seen from
Two such beams 102, 112 with disc tools 1 can be arranged such that the disc tools 1 on one beam 102 are offset in the transverse direction of the agricultural implement 100 relative to the disc tools 1 on the other beam 112. For example, the offset can be about 80-120% of the axial extent of the disc tools, preferably 100%+/−5%.
Moreover, the disc tools 1 on one beam 102 can have their rotation axes non-parallel to the disc tools 1 on the other beam 112.
For example, the disc tools 1 on one beam 102 can have their rotation axes Ar inclined relative to the longitudinal direction of the beam by about 15°-20° in one direction, and the disc tools on the other beam can have their rotation axes inclined relative to the longitudinal direction of the beam by about 15°-20° in the other direction.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1650815-2 | Jun 2016 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2017/050591 | 6/2/2017 | WO | 00 |
