WO2021080493A1

WO2021080493A1 - Agricultural implement and method of operating agricultural implement

Info

Publication number: WO2021080493A1
Application number: PCT/SE2020/051018
Authority: WO
Inventors: Rune Rommedahl; Crister Stark
Original assignee: Väderstad Holding Ab
Priority date: 2019-10-24
Filing date: 2020-10-21
Publication date: 2021-04-29
Also published as: SE1951211A1; SE543731C2

Abstract

This document discloses an agricultural implement (1) for drilling and/or tillage, comprising a frame (10) extending along a direction of travel (F), a traction coupling (14), arranged at a front portion of the frame (10), and at least one support wheel unit, arranged at a distance from the traction coupling. The agricultural implement has a first set (11a, 11b) of ground- engaging tools, which are arranged along a transverse direction of the agricultural implement, and a second set (12a, 12b) of ground-engaging tools, which are arranged along the transverse direction, and which are of another tool type than tools forming part of the first set of tools. Tools forming part of the first set (11a, 11b) of tools are arranged in front of tools forming part of the second set (12a, 12b) of tools, so that ground on which the agricultural implement is being driven is tilled first by at least one of the tools of the first set (11a, 11 b) and then by at least one of the tools of the second set (12a, 12b). A first subset (11 a) of the first set of tools (11a, 11b) is carried by a first tool carrier (111 a), which is pivotably attached to the frame in front of said support wheel unit, and a second subset (11 b) of the first set of tools (11 a, 11b) is carried by a second tool carrier (111 b), which is pivotably attached to the frame behind said support wheel unit. The document also discloses a method of operating the agricultural implement.

Description

AGRICULTURAL IMPLEMENT AND METHOD OF OPERATING AGRICULTURAL IMPLEMENT

Technical Field

This document discloses an agricultural implement and a method of operating the agricultural implement. More precisely, this document discloses an agricultural implement and a method that reduce the risk that a towing device of a traction vehicle connected to the agricultural implement is to be subjected to so-called “negative hook load”.

Background It is desirable to design agricultural implements with ever greater working width in order to be able to increase the productivity of the agricultural implements. This is true for both agricultural implements for tillage and agricultural implements for drilling, where both are examples of agricultural implements with ground-engaging tools. Non-limiting examples of the tools can be in the form of levelling implements, harrow tines, cultivator tines, harrow discs, furrow openers, seed discs, openers for fertilizer or pesticides and flattening or hoeing tools.

On the other hand, it is desirable to be able to transport the agricultural implement on public roads, which means limits on, for example, how wide and how high the agricultural implement is permitted to be when it is driven on public roads. Therefore, it is necessary to be able to fold up the agricultural implement.

One way of attaining as great a working width as possible and being able to drive the agricultural implement on public roads is to fold tool-carrying frame portions of the agricultural implement both upward and forward. This can, however, mean that the agricultural implement becomes tail-heavy, especially if it involves a seed drill, where a seed container, during folding of the agricultural implement, is empty. Such a tail-heavy agricultural implement can lead to negative hook load on the traction vehicle, which should be avoided or at least be mitigated or minimized, since traction couplings are not normally designed to withstand negative hook loads.

Therefore, there is a need for solutions in order to mitigate such tail heaviness of the agricultural implement and in order to reduce the risk of negative hook load on the traction coupling from occurring.

Summary

One object is thus to provide an improved agricultural implement, and in particular an agricultural implement where the risk of tail-heaviness and/or the emergence of negative hook load is reduced.

The invention is defined by the attached independent patent claims. Embodiments are set forth in the attached dependent patent claims, in the description that follows and in the accompanying drawings.

According to a first aspect, an agricultural implement for drilling and/or tillage is provided, comprising a frame extending along a direction of travel, a traction coupling, arranged at a front portion of the frame, and at least one support wheel unit, arranged at a distance from the traction coupling, a first set of ground-engaging tools, which are arranged along a transverse direction of the agricultural implement, a second set of ground-engaging tools, which are arranged along the transverse direction, and which are of another tool type than tools forming part of the first set of tools, wherein the tools forming part of the first set of tools are arranged in front of the second set of tools, so that ground on which the agricultural implement is being driven is tilled first by at least one of the tools of the first set and then by at least one of the tools of the second set, a first subset of the first set of tools being carried by a first tool carrier, which is pivotably attached to the frame in front of said support wheel unit, and a second subset of the first set of tools being carried by a second tool carrier, which is pivotably attached to the frame behind said support wheel unit.

“Support wheel unit” means a set of wheels that can comprise one or more wheels, which can be arranged directly on a main frame forming part of the frame, or on any form of support frame or rocker arm. “Ground-engaging tools” can be fixed or rotating, for examples furrow openers, fertilizer openers, levelling tools, flattening tools, cultivator tines, packer rollers, compactor wheels, cutting rollers, etc.

“Set of tools” means a group of tools which are of the same kind and have the same function, for example, by means of them being positioned in such a way on the agricultural implement that they fulfil the same function.

For example, a set of tools can be mounted on one and the same carrier and in a given position in relation to other sets of tools.

Different sets of tools can have tools of various types. Alternatively, two longitudinally separated sets of tools can consist of tools of the same type.

“Subset” means a number of tools included in the first set of tools, but that are fewer than a total number of tools included in the first set of tools.

A transverse direction can be perpendicular to the direction of travel (F). Alternatively, the transverse direction can deviate by up to 45 degrees to the direction of travel, viewed in a horizontal plane.

Preferably, all tools included in the first set of tools are of one and the same type, for example levelling tools, harrow tines, harrow discs, compactor wheels or tools with a breaking-up function.

Preferably, all tools included in the second set of tools are of one and the same type, for example levelling tools, harrow tines, harrow discs, compactor wheels, tools with a breaking-up function, furrow openers, seed discs or row units, each being designed to open a seed furrow, to place seed in the seed furrow and to seal the seed furrow and possibly also to compact the seed placed in the seed furrow.

By arranging a subset of the first set of tools in front of the support wheel unit, part of the weight is transferred to in front of the support wheel unit, and as a result, negative hook load on the traction coupling is mitigated.

In view of that, it becomes possible to make the sets of tools located behind the support wheel unit shorter, viewed in the direction of travel, which contributes to making it possible for the weight behind the support wheel unit to be reduced and for the lever with which the sets of tools act to be reduced. This also contributes to reducing the risk of negative hook load on the traction coupling. For example, the support wheel unit can comprise one or more pairs of wheels, where each pair of wheels comprises one wheel on either side of the frame. As an additional alternative, the support wheel unit can comprise one or more support frames or rocker arms, which in turn can carry wheel axles.

All tools in the second set can be carried by at least a third tool carrier, which is pivotably attached to the frame behind said support wheel unit.

The agricultural implement can have a centre line, which is parallel to the direction of travel, the first tool carrier extending in at least one direction laterally out from the centre line, with a first distance that is less than half the maximum width of the agricultural implement, a first end of the second tool carrier being located substantially at said first distance from the centre line and a second end of the second tool carrier being located at said distance from the centre line corresponding to half the width of the agricultural implement.

The second distance can be defined as half the maximum width of the agricultural implement minus the first distance.

“The second tool carrier being located substantially at said first distance” means that an overlap can exist between the tool carriers, which overlap can be sufficient in order to ensure that all the ground which the agricultural implement is passing over can be tilled, even when the agricultural implement is turning.

The first tool carrier can be pivotable in a horizontal plane, between a working mode and a transport mode.

The first tool carrier can be pivotable in a forward direction in relation to a pivot axis about which the tool carrier is pivotable.

The first tool carrier can be pivotable about a substantially vertical axis which is located in front of the support wheel unit.

The first tool carrier can comprise a first portion, extending in a first horizontal transverse direction from the centre line, so that its one end is located at the centre line and so that its other end is located at said first distance from the centre line, and the first tool carrier comprising a second portion, extending in a second, opposite, horizontal transverse direction from the centre line, so that its one end is located at the centre line and so that its other end is located at said first distance from the centre line.

The first tool carrier can comprise a first portion, which, in the working mode, extends from a centre of the agricultural implement, viewed in a transverse direction and along a direction which is substantially perpendicular to the direction of travel, and a second portion, which, in the working mode, extends from said centre of the agricultural implement and along a direction which is substantially perpendicular to the direction of travel.

Each of the tool carriers can comprise one or more portions which are movable or pivotable in relation to each other. Any one of such portions, for example a centre portion, can be fixed in relation to the frame, wherein at least one portion arranged laterally of such centre portion can be pivotable.

The support wheel unit can comprise a wheel bogie unit, which comprises a front pair of wheels and a rear pair of wheels, wherein the agricultural implement can further comprise a setting device, for controlling at least one of the front pair of wheels and the rear pair of wheels, and wherein the setting device can be adjustable so that substantially all of the load applied on the wheel bogie unit is taken up by the rear pair of wheels.

A pair of wheels comprises at least one wheel on the left-hand side of a centre line parallel to the direction of travel of the agricultural implement and at least one wheel on the right-hand side of the centre line, which have a common geometrical axis of rotation.

A wheel bogie unit comprises at least two pairs of wheels which are mounted adjacent each other, in the longitudinal direction, with an axle spacing below, for example, 3 metres, 2.5 metres or 2 metres. A wheel bogie unit can, but does not have to, comprise a support frame, which can be moveable in relation to a main frame. Wheels and axles forming part of a wheel bogie unit can thus be mounted directly to the main frame of the agricultural implement.

By setting the wheel bogie unit so that all load is taken up by a rear pair of wheels, the horizontal axis about which torque affecting the load on the traction coupling is acting is moved rearward, so that the traction coupling obtains a greater lever and a load located behind the wheel bogie unit obtains a smaller lever. Thus the risk of negative hook load on the traction coupling is reduced.

It will be appreciated that the equivalent can be utilized for wheel bogie units comprising more than two pairs of wheels, for example 3- or 4-axle wheel bogie units. In the case of such applications, therefore only the rear pair of wheels can be lowered, or all pairs of wheels except the rear can be raised, in order to apply all load to the rear pair of wheels.

Furthermore, it will be appreciated that a wheel bogie unit can be provided with so-called bogie bands, which are known per se and can run across two or more wheels. Bogie bands can be made from rubber or from metal.

The wheel bogie unit can comprise a rocker arm, which carries a front wheel and a rear wheel, wherein the rocker arm can be pivotable in relation to the frame about a horizontal geometrical axis which is perpendicular to the direction of travel, and wherein the geometrical axis can be arranged between the geometrical axes of rotation for said front and rear wheel respectively, wherein the setting device can comprise a limiting device, for limiting the pivotability of the rocker arm in relation to the frame, so that the rocker arm is prevented in at least one direction from pivoting in relation to the frame.

The limiting device can comprise an actuator, for example a hydraulic actuator, which is configured to provide a force between the frame and a rocker arm portion located at a distance from the transverse geometrical axis.

The limiting device can comprise an arm, which has a proximal end, which is pivotably attached in relation to the frame, and a distal end, with which the hydraulic actuator is connected, so that the hydraulic actuator is operable between the frame and the distal end of the frame, wherein the arm can have a bearing portion which is aligned with the rocker arm, and wherein the arm can be adjustable using the actuator between a first position, where the rocker arm is pivotable about the transverse geometrical axis and a second position, where the rocker arm is at least partly prevented from pivoting about the transverse geometrical axis.

The distal end of the arm can extend rearward in relation to the transverse geometrical axis, so that a rocker arm portion located behind the transverse geometrical axis is prevented from moving upward, in the second position.

The actuator and the arm can be configured to press a rear portion of the rocker arm downward, so that at least 80% of a load applied on the wheel bogie unit is distributed on said rear wheel, preferably at least 90% or substantially 100%.

The setting device can comprise an actuator acting between the rear pair of wheels and the frame.

The setting device can comprise an actuator acting between the front pair of wheels and the frame.

The agricultural implement can comprise at least one transverse frame portion, which carries a ground-engaging tool.

The frame can comprise a main frame and at least a side frame portion arranged pivotably in relation to the frame.

Said side frame portion can be pivotable in relation to the main frame about at least one axis which is substantially parallel to the direction of travel.

The frame can comprise a support frame arranged pivotably in relation to the main frame.

Said support frame can be pivotable about at least one axis which is substantially horizontal and perpendicular to the direction of travel.

Said side frame portion can be pivotably attached in relation to the support frame about at least one axis which is substantially parallel to the direction of travel.

Said side frame portion and/or said support frame can carry a number of ground-engaging tools.

According to a second aspect, a method of operating an agricultural implement for drilling and/or tillage is provided, which agricultural implement comprises a main frame extending along a direction of travel, a traction coupling, arranged at a front portion of the frame, and at least one support wheel unit, arranged at a distance from the traction coupling, a first set of ground-engaging tools, which are arranged along a transverse direction of the agricultural implement, a second set of ground-engaging tools, which are arranged along the transverse direction, and which are of another tool type than the tools forming part of the first set of tools. The method comprises from a working mode, folding a subset of the first set of ground-engaging tools, and then folding the second set of tools and a remaining subset of the first set of tools.

Said subset of the first set of ground-engaging tools can be folded in front of the support wheel unit, and said second set of ground-engaging tools and said remaining subset of the first set of tools can be folded behind said support wheel unit.

For the method, said support wheel unit can comprise a wheel bogie unit, which comprises a front pair of wheels and a rear pair of wheels, wherein the method can comprise setting the wheel bogie unit so that substantially all of the load applied on the wheel bogie unit is taken up by the rear pair of wheels.

The wheel bogie unit can comprise a rocker arm, which carries a front wheel and a rear wheel, wherein the rocker arm can be pivotable in relation to the frame about a horizontal transverse geometrical axis, and wherein the rocker arm can be arranged between the geometrical axes of rotation for said front and rear wheel respectively, wherein the method comprises: limiting the rocker arm relative to the frame, so that pivoting in at least one direction about the horizontal transverse axis is prevented.

The method can further comprise increasing a vertical distance between the rear wheel and the frame, so that a greater part of a load applied on the wheel bogie unit is distributed on the rear wheel.

Said setting or limiting can be provided as a part of a folding operation, wherein at least one support frame portion and/or at least a side frame portion is folded in relation to the frame between a working mode and a transport mode.

Said setting or limiting can be provided during travel of the agricultural implement, so that a working depth for at least one ground-engaging tool carried by the agricultural implement is reduced.

In the method, the agricultural implement can be constructed such that the first set of tools is arranged in front of the second set of tools, so that ground on which the agricultural implement is being driven is tilled first by at least one of the tools of the first set and then by at least one of the tools of the second set. Furthermore, a first subset of the first set of tools can be carried by a first tool carrier, which is pivotably attached to the frame in front of said support wheel unit.

A second subset of the first set of tools can be carried by a second tool carrier, which is pivotably attached to the frame behind said support wheel unit. The agricultural implement can have a centre line, which is parallel to the direction of travel.

The first tool carrier can extend in at least one direction laterally out from the centre line, with a first distance that is less than half the maximum width of the agricultural implement.

A first end of the second tool carrier can be located substantially at said first distance from the centre line and a second end of the second tool carrier is located at a distance from the centre line corresponding to half the width of the agricultural implement.

Brief description of the drawings

Fig. 1 shows a schematic perspective view of an agricultural implement, viewed obliquely from the back.

Figs 2a-2c show schematic views of a wheel bogie unit.

Figs 3a-3b show schematic side views of a unit comprising a traction vehicle and an agricultural implement.

Fig. 4 shows a schematic view from above of an agricultural implement.

Fig. 5 shows a schematic view from above of an agricultural implement.

Fig. 6 shows a schematic view from the side of an agricultural implement.

Detailed description

Fig. 1 shows an agricultural implement in the form of a seed drill 1 , which comprises a frame 10, which has at least one longitudinal main frame 100 and at least one transverse frame portion 111a, 111b; 121a, 121b. The seed drill has at least one wheel 132, 133, a seed container 12 and a traction coupling 14, by means of which the agricultural implement can be coupled to a traction vehicle, such as a tractor, to be drawn in a direction of travel F.

In the example shown, the agricultural implement is formed by a seed drill, and especially a seed drill for volumetric feeding of seed.

The concepts shown herein can also be applied to precision seed drills and to other types of machines for feeding material, especially granular material, to the ground on which the agricultural implement is travelling.

Furthermore, the concepts shown herein can be applied to soil-working agricultural implements, for example cultivators, harrows and the like.

The agricultural implement frame 10 can comprise one or more side portions 102, which can be foldable between a working mode and a transport mode. For example, the agricultural implement can have two, three, four or five portions which in the working mode are located next to one another, and each can carry a plurality of ground-engaging tools, such as row units, but also furrow openers, fertilizer openers, levelling tools, flattening tools, cultivator tines, packer rollers, compactor wheels, cutting rollers, etc.

Such side portions can be foldable about one or more axes which are substantially parallel to the direction of travel and preferably horizontal.

Furthermore, the agricultural implement frame 10 can comprise one or more front portions and/or rear portions pivotable or foldable in relation to a centre portion. For example, a front portion can comprise levelling tools and a rear portion can comprise compacting tools, such as any form of packer.

For agricultural implements with two or more side portions 102, each side portion can have a front portion and/or a rear portion which can be foldable with the respective side portions.

The agricultural implement shown in Fig. 1 has a large number of row units 2, which are arranged along two separated rows in the direction of travel F. The row units in a front row can be laterally displaced relative to the row units in a row positioned behind, such that a greater row density can be provided than would be allowed by the width of the row units if all row units were located on the same row. The displacement can be in the region of 40- 60% of a distance between two adjacent row units in any of the rows. Specifically, Fig. 1 shows an agricultural implement comprising a wheel bogie unit 13, which will be described in more detail below.

The agricultural implement has a main frame 100 and side frames 102. A support frame 101 is pivotably attached to the main frame 101 about a horizontal link which is substantially perpendicular to the direction of travel F. Pivoting of the support frame about the link is provided using a set of support frame actuators 21.

The side frames 102 are each pivotably attached to the support frame about horizontal links which are substantially parallel to the direction of travel F. Pivoting of the side frames about the link is provided using a set of side frame actuators 22, which can be formed of hydraulic cylinders and which act between the support frame 101 and the respective side frame 102.

By means of the above arrangement the side frames 102 can be folded to the support frame 101 , wherein the support frame 101 is then folded forward to the main frame 100.

Both the support frame 101 and the side frames 102 are arranged behind the wheel bogie unit 13.

The support frame 101 and the side frames 102 carry a pair of sets of tools 12a, 12b, which in the example shown is constituted by the row units 2. The row units 2 which constitute one of the sets of tools 12a are arranged along a first transverse beam 121a. The row units which constitute a second one of the sets of tools 12b are arranged along a second transverse beam 121 b, which is arranged behind the first transverse beam 121 a.

At the outermost portion of the first transverse beam in a lateral direction, a subset of a set of front implements 11 b is arranged, here in the form of levelling tools. This set 11 b is mounted along a transverse beam 111b, which extends across a part of the width of the agricultural implement.

The remaining subset of the set of front implements 11 a is arranged on a separate transverse beam 111a, which is pivotably arranged on the main frame 100 in front of the wheel bogie unit 13.

The first subset of the set of front implements 11 a is thus, for each side of the agricultural implement, arranged along the first transverse beam 111a, which is mounted in front of the wheel bogie unit 13 and which extends from the centre line C of the agricultural implement and outward, with a distance a1 which is less than half of the maximum width bmax of the agricultural implement. Typically, the distance a1 can be approximately 30-70% of half the maximum width of the agricultural implement (not counting any marker implements).

The second subset of the set of front implements 11 b is, for each side of the agricultural implement, arranged along the second transverse beam 111 b, which is mounted on the side frame 102 and extends a distance a2 which is approximately half of the maximum width of the agricultural implement minus distance a1 .

With reference to Figs 2a-2c, the wheel bogie unit 13 will now be described in more detail.

The wheel bogie unit 13 comprises, for wheels on each side, a rocker arm 131 , which carries at least two wheels 132, 133 for each side of the agricultural implement, and which is pivotably attached in relation to the main frame 100 about a transverse horizontal geometrical axis 134. The wheels 132, 133 have geometrical axes of rotation 1321 , 1331 , which are arranged in front of and behind the transverse horizontal geometrical axis 134.

A limiting device 135 is arranged to limit pivoting of the rocker arm 131 relative to the main frame 100, so that the rocker arm is prevented from pivoting relative to the main frame. In addition, the limiting device 135 can be arranged to load the rocker arm 131 so that the weight applied on the wheel bogie unit 13 only loads a rear wheel 133 of the wheels.

For example, the limiting device 135 can comprise an actuator 1350, for example a hydraulic actuator, acting between the main frame 100 and an arm 1351 , wherein the arm has a proximal end 1352 pivotably attached to the main frame 100 or to the rocker arm 131 and a distal end 1353 at which the actuator 1350 can be attached. Furthermore, the arm 1351 can have a contact surface (not shown) for contact against the rocker arm 131 , with which the arm can be aligned.

By means of activating the actuator 1350, illustrated in Fig. 2c, so that its plunger is projecting outward, the contact surface of the arm 1351 will bear against the rocker arm 131 and thus prevent this from pivoting in at least one direction.

By means of fully projecting the plunger, the rear portion of the rocker arm 131 can also be pressed downward, so that the rear portion is lowered in relation to the main frame 100, wherein the front wheel 132 is raised from engagement with the ground and all load on the wheel bogie unit 13 is placed on the rear wheel 133.

The corresponding operation can be carried out on the rocker arms on both sides.

By means of instead fully retracting the plunger, the rocker arm 131 can move freely.

Fig. 3a shows the wheel bogie unit 13 in its non-limiting position, wherein the load is evenly distributed on the front and the rear wheels 132, 133. As illustrated, slightly exaggeratedly, in Fig. 3a, this can lead to the traction coupling of the tractor being subjected to a negative hook load in a worst case scenario.

Fig. 3b shows the wheel bogie unit 13 in its limiting position, with the front wheels 132 retracted and all load on the rear wheels. As a result, the lever of the traction coupling is extended, which contributes to reducing the risk of negative hook load on the traction coupling.

Fig. 4 schematically shows how a first set of tools 11a, 11b can be distributed between a first subset being carried in front of the wheel bogie unit 13 and a second subset being carried behind the wheel bogie unit 13 and more specifically, on the side frame portions 102.

Fig. 4 also illustrates the measurement a1 , which corresponds to the distance from the centre line C to the outer end of the first tool carrier 111a in a lateral direction.

Fig. 4 also illustrates the measurement a2, which corresponds to the distance from the inner end of the second tool carrier 111b and its outer end in a lateral direction.

Furthermore, the maximum total width bmax of the agricultural implement is illustrated. Normally, it can be appropriate to allow both subsets of the first set of tools 11a, 11 b to overlap slightly, preferably sufficiently to ensure tillage across the entire width even when the unit is turning. Such an overlap can be approximately 2-10%, preferably 3-7% or approximately 5%, of the distance from the centre line C to the outer end of the first tool carrier 111 a in a lateral direction, i.e. measurement a1.

Fig. 5 shows how the front tool carriers 111a can be arranged in a foldable manner in front of the wheel bogie unit 13. Specifically, the respective actuators 23, for example hydraulic cylinders, can be used for controlling the position of the front tool carriers 111a.

As will be seen in Fig. 5, the front tool carriers can be pivotable about respective, substantially vertical geometrical axes, which are located in front of the wheel bogie unit 13 viewed in the direction of travel.

As will be seen in Fig. 5, the front tool carriers can be divided into one, two or three sections, where any one of the sections can be fixed and at least one can be pivotable.

As will be seen in Fig. 5, the tool carriers 111a can be folded forward.

Fig. 6 shows how, with reference to the limiting device 135 shown in Figs 2a-2b, this can be utilized in order to, during travel, affect the drilling depth of a seed drill equipped with such a limiting device and the working depth for other types of tools and for only soil-working implements.

By means of operating the actuator 1350 so that the rear wheel 133 is pressed downward in relation to the frame 100, the rear portion of the frame 100 will be raised in relation to the ground and the drilling depth is thus reduced.

By means of instead retracting the actuator 1350, the rear portion of the frame can be lowered to the position where both wheels 132, 133 bear against the ground, wherein the frame is lowered and the drilling depth is thus increased.

Correspondingly, the limiting device 135 can be used in order to set the working depth of a soil-working agricultural implement, for example a harrow or a cultivator. The setting of the limiting device 135 can be synchronized with any additional support wheels, carrier rollers or packer rollers on the agricultural implement, in order to ensure that the depth of all tools is set correctly.

Claims

1. Agricultural implement (1 ) for drilling and/or tillage, comprising: a frame (10) extending along a direction of travel (F), a traction coupling (14), arranged at a front portion of the frame (10), and at least one support wheel unit, arranged at a distance from the traction coupling, a first set (11a, 11b) of ground-engaging tools, which are arranged along a transverse direction of the agricultural implement, a second set (12a, 12b) of ground-engaging tools, which are arranged along the transverse direction, and which are of another tool type than tools forming part of the first set of tools, wherein the first set (11a, 11b) of tools is arranged in front of the second set (12a, 12b) of tools, so that ground on which the agricultural implement is being driven is tilled first by at least one of the tools of the first set (11a, 11b) and then by at least one of the tools of the second set (12a, 12b), wherein a first subset (11 a) of the first set of tools (11a, 11b) is carried by a first tool carrier (111 a), which is pivotably attached to the frame (10) in front of said support wheel unit, and wherein a second subset (11 b) of the first set of tools (11a, 11b) is carried by a second tool carrier (111 b), which is pivotably attached to the frame (10) behind said support wheel unit.

2. Agricultural implement according to Claim 1 , wherein all tools in the second set (12a, 12b) are carried by at least a third tool carrier (121 a, 121b), which is pivotably attached to the frame (10) behind said support wheel unit.

3. Agricultural implement according to either Claim 1 or 2, wherein the agricultural implement has a centre line (C), which is parallel to the direction of travel (F), wherein the first tool carrier extends in at least one direction laterally out from the centre line (C), with a first distance (a1) that is less than half the maximum width (bmax) of the agricultural implement, wherein a second distance (a2) is defined as half the maximum width of the agricultural implement minus the first distance (a1), a first end of the second tool carrier being located substantially at said first distance from the centre line and a second end of the second tool carrier being located at said distance (a1+a2) from the centre line corresponding to half the width (bmax) of the agricultural implement.

4. Agricultural implement according to any one of Claims 1 -3, wherein the first tool carrier (111a) is pivotable in a horizontal plane, between a working mode and a transport mode.

5. Agricultural implement according to any one of Claims 1 -4, wherein the first tool carrier (111a) is pivotable in a forward direction in relation to a pivot axis about which the tool carrier (111a) is pivotable.

6. Agricultural implement according to any one of Claims 1 -5, wherein the first tool carrier (111a) is pivotable about a substantially vertical axis which is located in front of the support wheel unit.

7. Agricultural implement according to any one of Claims 3-6, wherein the first tool carrier (111a) comprises a first portion, extending in a first horizontal transverse direction from the centre line (C), so that its one end is located at the centre line and so that its other end is located at said first distance (a1) from the centre line, and wherein the first tool carrier (111a) comprises a second portion, extending in a second, opposite, horizontal transverse direction from the centre line, so that its one end is located at the centre line and so that its other end is located at said first distance from the centre line.

8. Agricultural implement according to any one of Claims 1 -7, wherein the first tool carrier (111a) comprises: a first portion, which, in the working mode, extends from a centre of the agricultural implement, viewed in a transverse direction and along a direction which is substantially perpendicular to the direction of travel (F), and comprises a second portion, which, in the working mode, extends from said centre of the agricultural implement and along a direction which is substantially perpendicular to the direction of travel.

9. Agricultural implement according to any one of the preceding claims, wherein the support wheel unit comprises a wheel bogie unit (13), which comprises a front pair of wheels and a rear pair of wheels, wherein the agricultural implement further comprises a setting device, for controlling at least one of the front pair of wheels and the rear pair of wheels, wherein the setting device is adjustable so that substantially all of the load applied on the wheel bogie unit is taken up by the rear pair of wheels.

10. Agricultural implement according to Claim 9, wherein the wheel bogie unit comprises a rocker arm (131 ), which carries a front wheel (132) and a rear wheel (133), wherein the rocker arm (131) is pivotable in relation to the frame (10) about a horizontal geometrical axis (134) which is perpendicular to the direction of travel (F), and wherein the geometrical axis (134) is arranged between the geometrical axes of rotation (1321 , 1331 ) for said front and rear wheel (132,

133) respectively, and wherein the setting device comprises a limiting device (135), for limiting the pivotability of the rocker arm (131 ) in relation to the frame (10), so that the rocker arm (131) is iprevented in at least one direction from pivoting in relation to the frame (10).

11. Agricultural implement according to Claim 10, wherein the limiting device comprises an actuator, for example a hydraulic actuator (1350), which is configured to provide a force between the frame and a rocker arm (131) portion located at a distance from the transverse geometrical axis (134).

12. Agricultural implement according to either Claim 10 or 11 , wherein the limiting device comprises: an arm (1351), which has a proximal end (1352), which is pivotably attached in relation to the frame (10), and a distal end (1353), with which the hydraulic actuator (1350) is connected, so that the hydraulic actuator (1350) is operable between the frame (10) and the distal end (1353) of the arm (1351), wherein the arm (1351) has a bearing portion which is aligned with the rocker arm (131), and wherein the arm (1351) is adjustable using the actuator (1350) between a first position, where the rocker arm (131) is pivotable about the transverse geometrical axis and a second position, where the rocker arm (131) is at least partly prevented from pivoting about the transverse geometrical axis.

13. Agricultural implement according to Claim 12, wherein the distal end of the arm extends rearward in relation to the transverse geometrical axis, so that a rocker arm portion located behind the transverse geometrical axis is prevented from moving upward, in the second position.

14. Agricultural implement according to either Claim 11 or 12, wherein the actuator and the arm are configured to press a rear portion of the rocker arm downward, so that at least 80% of a load applied on the wheel bogie unit is distributed on said rear wheel, preferably at least 90% or substantially 100%.

15. Agricultural implement according to Claim 10, wherein the setting device comprises an actuator acting between the rear pair of wheels and the frame (10).

16. Agricultural implement according to either Claim 10 or 15, wherein the setting device comprises an actuator acting between the front pair of wheels (132) and the frame (10).

17. Agricultural implement according to any one of the preceding claims, wherein the agricultural implement comprises at least one transverse frame portion (111 a, 111 b; 121 a, 121 b), which carries a ground-engaging tool (11 a, 11 b, 12a, 12b).

18. Agricultural implement according to any one of the preceding claims, wherein the frame (10) comprises a main frame (100) and at least a side frame portion (102) arranged pivotably in relation to the main frame.

19. Agricultural implement according to Claim 18, wherein said side frame portion is pivotable in relation to the main frame (100) about at least one axis which is substantially parallel to the direction of travel (F).

20. Agricultural implement according to either Claim 18 or 19, wherein the frame comprises a support frame (101 ) arranged pivotably in relation to the main frame (100).

21 . Agricultural implement according to Claim 20, wherein said support frame (101 ) is pivotable about at least one axis which is substantially horizontal and perpendicular to the direction of travel (F).

22. Agricultural implement according to either Claim 20 or 21 , wherein said side frame portion is pivotably attached in relation to the support frame (101) about at least one axis which is substantially parallel to the direction of travel (F).

23. Agricultural implement according to any one of Claims 18-22, wherein said side frame portion and/or said support frame carries a plurality of ground-engaging tools.

24. Method of operating an agricultural implement (1 ) for drilling and/or tillage, which agricultural implement comprises: a frame (10) extending along a direction of travel (F), a traction coupling (14), arranged at a front portion of the frame (10), and at least one support wheel unit, arranged at a distance from the traction coupling, a first set of ground-engaging tools, which are arranged along a transverse direction of the agricultural implement, a second set of ground-engaging tools, which are arranged along the transverse direction, and which are of another type of tools than the first set of tools, wherein the method comprises: from a working mode, folding a subset of the first set of ground- engaging tools, and then folding the other set of tools and a remaining subset of the first set of tools.

25. Method according to Claim 24, wherein said subset of the first set of ground-engaging tools is folded in front of the support wheel unit, and wherein said second set of ground-engaging tools and said remaining subset of the first set of tools is folded behind said support wheel unit.

26. Method according to either Claim 24 or 25, wherein said support wheel unit comprises a wheel bogie unit, which comprises a front pair of wheels and a rear pair of wheels, wherein the method comprises setting the wheel bogie unit so that substantially all of the load applied on the wheel bogie unit is taken up by the rear pair of wheels.

27. Method according to Claim 26, wherein the wheel bogie unit (13) comprises a rocker arm (131 ), which carries a front wheel (132) and a rear wheel (133), wherein the rocker arm (131) is pivotable in relation to the frame (10) about a horizontal transverse geometrical axis (134), and wherein the rocker arm (131) is arranged between the geometrical axes of rotation (1321 , 1331 ) for said front and rear wheel (132, 133) respectively, wherein the method comprises: limiting the rocker arm relative to the frame, so that pivoting in at least one direction about the horizontal transverse axis (134) is prevented.

28. Method according to Claim 27, further comprising increasing a vertical distance between the rear wheel (133) and the frame, so that a greater part of a load applied on the wheel bogie unit is distributed on the rear wheel (133).

29. Method according to any one of Claims 26-28, wherein said setting or limiting is provided as a part of a folding operation, wherein at least one support frame portion (101) and/or at least one side frame portion (102) is folded in relation to the frame (100) between a working mode and a transport mode.

30. Method according to any one of Claims 26-29, wherein said setting or limiting is provided during travel of the agricultural implement (1), so that a working depth for at least one ground-engaging tool carried by the agricultural implement is reduced.

31. Method according to any one of Claims 24-30, wherein tools forming part of the first set (11a, 11b) oftools are arranged in front of tools forming part of the second set (12a, 12b) of tools, so that ground on which the agricultural implement is being driven is tilled first by at least one of the tools of the first set (11a, 11b) and then by at least one of the tools of the second set (12a, 12b), wherein a first subset (11 a) of the first set of tools (11a, 11b) is carried by a first tool carrier (111 a), which is pivotably attached to the frame in front of said support wheel unit, and wherein a second subset (11 b) of the first set of tools (11a, 11b) is carried by a second tool carrier (111 b), which is pivotably attached to the frame behind said support wheel unit, and wherein the agricultural implement has a centre line (C), which is parallel to the direction of travel (F), wherein the first tool carrier extends in at least one direction laterally out from the centre line (C), with a first distance (a1 ) that is less than half the maximum width (bmax) of the agricultural implement, and a first end of the second tool carrier being located substantially at said first distance from the centre line and a second end of the second tool carrier being located at a distance (a1+a2) from the centre line corresponding to half the width (bmax) of the agricultural implement.