Agricultural implements comprising a straw harrow

Abstract

An agricultural implement (1), comprises an implement frame (10, 11, 12, 13, 14, 101) and a straw harrow (100). The straw harrow (100) comprises a supporting body (102), which is rotatably mounted relative to the implement frame (10, 11, 12, 13, 14, 101) about a rotation axis (Ar), and which supports a plurality of straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) projecting generally radially and / or tangentially outwardly from the supporting body (102). At least some of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) comprise a mounting portion (10211), a working portion (10213, 10214, 10215, 10216, 10217) and a spring portion (10212), such that the working portion (10213, 10214, 10215, 10216, 10217) is resiliently movable relative to the mounting portion (10211). The spring portion (10212) is at least partially recessed into the supporting body (102). There is further disclosed a method of operating a straw harrow as well as a straw harrow tine.

Description

[0001] AGRICULTURAL IMPLEMENTS COMPRISING A STRAW HARROW

[0002] Technical field

[0003] The present disclosure relates to agricultural implements comprising a straw harrow, to methods of operating such agricultural implements and to straw harrow tines which can be used in such agricultural implements.

[0004] Background

[0005] Subsequent to harvesting a crop, it is desirable to distribute crop residues, which are left on the field, evenly over the field, since an uneven distribution may lead to variations in the soil chemistry across the field as the crop residues decompose. Such variations may cause uneven germination and growth of subsequent crops.

[0006] While some harvesters are designed to distribute crop residues somewhat evenly, most harvesters still do not achieve an optimal distribution of crop residues. Hence, there remains a potential for increasing yield by further enhancing crop residue distribution.

[0007] To this end, straw harrows have been used for some time. Such straw harrows are conventionally designed with a plurality of relatively slender straw harrow tines, which are distributed over the length and width of the straw harrow, e.g. as illustrated in WO2023 / 282831A2.

[0008] However, as it may be desirable to provide an agricultural implement, such as a cultivator, with tines, discs, or both, a seeder or a planter, with several functions, and as there is limited space available in the longitudinal direction of the agricultural implement, there was a need for a more compact straw harrow.

[0009] DE102004028912A1 suggests to address this need by providing a straw harrow comprising a supporting body, which is rotatably mounted relative to an implement frame about a rotation axis and which supports a plurality of straw harrow tines that project generally radially outwardly from the supporting body. There is also disclosed a drive arrangement for such a straw harrow.

[0010] However, a straw harrow such as the one disclosed in DE102004028912A1 has proven to be fragile and so has not yet achieved any significant commercial success. As the general need for a more compact straw harrow remains, there is a need to provide such a more reliable compact straw harrow.

[0011] It is an objective of the present disclosure to provide an agricultural implement comprising an improved straw harrow functionality, which is compact, yet effective.

[0012] The invention is defined by the appended independent claims. Embodiments are set forth in the dependent claims, in the following description and in the drawings.

[0013] According to a first aspect, there is provided an agricultural implement, comprising an implement frame and a straw harrow. The straw harrow comprises a supporting body, which is rotatably mounted relative to the implement frame about a rotation axis, and which supports a plurality of straw harrow tines projecting generally radially and / or tangentially outwardly from the supporting body, wherein at least some of the straw harrow tines comprise a mounting portion, a working portion and a spring portion, such that the working portion is resiliently movable relative to the mounting portion. The spring portion is at least partially recessed into the supporting body.

[0014] The agricultural implement may be a dedicated straw harrow implement, or a combination implement comprising the straw harrow and at least one further type of ground engaging tool. The further type of ground engaging tool may be selected from a group consisting of levelling tools, harrow tines, cultivator tines, mixing tools, cutting tools, reconsolidating tools, packing tools, planting or seeding devices, and fertilizer- or pesticide dispensing devices.

[0015] The term "mounted relative to the implement frame" covers embodiments where the supporting body is mounted directly to the implement frame and embodiments where the supporting body is mounted to a subframe, such as to a dedicated straw harrow frame and / or to a side section frame, which, in turn, is mounted to the implement frame.

[0016] By providing the spring portion in a recess into the supporting body, it is possible to achieve a combination of a very resilient straw harrow tine which operates about a very compact hub, such that the risk of straw, soil and other debris interfering with the supporting body is minimized.

[0017] The spring portion may comprise at least one helical portion.

[0018] The provision of a helical portion increases the resilience of the straw harrow tine. Ideally, this spring portion is at least partially recessed into the supporting body.

[0019] At least part of the working portion may extend from the spring portion in a direction which is substantially tangential relative to the rotation axis.

[0020] The working portion may comprise a concave portion which is inwardly concave towards the rotation axis.

[0021] This concave portion may be arranged such that a direction from the spring portion and outwardly along the concave portion points along the direction of rotation of the supporting body.

[0022] The working portion may comprise a convex portion, arranged radially outwardly of the concave portion, which is inwardly convex towards the rotation axis.

[0023] The working portion may comprise a first straight portion connecting the concave portion and the convex portion.

[0024] The first straight portion may extend at an angle of about 70-90 degs, preferably about 75-85 degs relative to a radial direction from the rotation axis.

[0025] The extension of the first straight portion is defined when the tine is in a nonbiased state, i.e. a state wherein it is not being subjected to any external forces.

[0026] The working portion may comprise a second straight portion, arranged radially outwardly of the convex portion.

[0027] The second straight portion may extend at an angle of about 10-40 degs, preferably about 20-30 degs, relative to a radial direction from the rotation axis.

[0028] The extension of the second straight portion is defined when the tine is in a non-biased state, i.e. a state wherein it is not being subjected to any external forces.

[0029] The mounting portion, the working portion and the spring portion may present a substantially constant cross section.

[0030] The mounting portion, the working portion and the spring portion may be formed from a single piece of material, in particular a metal wire. The supporting body has a closed cross section, such as a circular cross section.

[0031] The agricultural implement may further comprise a drive motor, for rotatably driving the supporting body, or a brake device, for braking a rotation of the supporting body.

[0032] The agricultural implement may further comprise a transmission operatively connecting the drive motor, or the braking device, to the supporting body.

[0033] The transmission may be configured such that when advancing the agricultural implement along a working direction, the supporting body is caused to rotate in a forward direction, such that radially outermost portions of each of the straw harrow tines, when positioned at a lowermost point of its rotation about the rotation axis, have a ground speed that is lower than that of the implement frame but greater than zero.

[0034] The transmission may comprise a worm gear having a toothed wheel fixedly connected to the supporting body and a spiral thread wheel fixedly connected to the drive motor.

[0035] By using a thus configured worm gear type transmission, forces applied to the straw harrow tines, so as to cause a torque about the rotation axis, will not be transferred to the drive motor.

[0036] The agricultural implement may further comprise a freewheel configured to disengage the drive motor or brake device from the supporting body when a forward travel velocity of the agricultural implement is less than a forward velocity of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis.

[0037] Hence, the freewheel will protect the worm gear from being damaged in the event of a sudden stop of the agricultural implement, or in the event of the agricultural implement being reversed.

[0038] The transmission may be configured such that when advancing the agricultural implement along a working direction, the supporting body is caused to rotate in a forward direction, such that radially outermost portions of the straw harrow tines, while positioned below the axis of rotation, have a ground speed that is lower than that of the implement frame but greater than zero. The agricultural implement may be configured such that, when one of the straw harrow tines is at a lowermost point of its rotation about the rotation axis, the convex portion is rearwardly convex relative to the working direction.

[0039] According to a second aspect, there is provided an agricultural implement, comprising an implement frame and a straw harrow. The straw harrow comprises a supporting body, which is rotatably mounted relative to the implement frame about a rotation axis and which supports a plurality of straw harrow tines projecting generally radially outwardly from the supporting body, a drive motor, for driving the supporting body, and a transmission for operatively connecting the drive motor to the supporting body. The transmission comprises a worm gear having a toothed wheel fixedly connected to the supporting body and a spiral thread wheel fixedly connected to the drive motor.

[0040] The agricultural implement may further comprise a freewheel configured to disengage the drive motor from the supporting body when a forward travel velocity of the agricultural implement is less than a forward velocity of radially outermost portions of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis.

[0041] The transmission may be configured such that when advancing the agricultural implement along a working direction, the supporting body is caused to rotate in a forward direction, such that radially outermost portions of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis, have lower ground speed than the implement frame.

[0042] According to a third aspect, there is provided an agricultural implement, comprising an implement frame and a straw harrow. The straw harrow comprises a supporting body, which is rotatably mounted relative to the implement frame about a rotation axis and which supports a plurality of straw harrow tines projecting generally radially outwardly from the supporting body, a drive motor, for driving the supporting body, or a brake device for braking a rotation of the supporting body, and a freewheel configured to disengage the drive motor or braking device from the supporting body when a forward travel velocity of the agricultural implement is less than a forward velocity a radially outermost portions of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis. The agricultural implement may further comprise a transmission for connecting the drive motor or braking device to the supporting body.

[0043] The transmission may be configured such that when advancing the agricultural implement along a working direction, the supporting body is caused to rotate in a forward direction, such that radially outermost portions of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis, have lower ground speed than the implement frame.

[0044] According to a fourth aspect, there is provided a method of operating an agricultural implement, comprising an implement frame and a straw harrow. The straw harrow comprises a supporting body, which is rotatably mounted relative to the implement frame about a rotation axis and which supports a plurality of straw harrow tines projecting generally radially and / or tangentially outwardly from the supporting body. At least some of the straw harrow tines comprise a mounting portion, a working portion and a spring portion, such that the working portion is resiliently displaceable relative to the mounting portion. The method comprises causing the agricultural implement to move in a working direction at a predetermined ground speed, while causing the agricultural implement to move in the working direction at the predetermined ground speed, using a drive motor or a braking device to cause the supporting body to rotate such that radially outermost portions of each of the straw harrow tines when positioned at a lowermost point of its rotation about the rotation axis, have a ground speed that is lower than that of the implement frame but greater than zero, and causing the supporting body to be mechanically disconnected from the drive motor in the event the ground speed of the agricultural implement falls below that the ground speed of the radially outermost portions of each of the straw harrow tines, when positioned at a lowermost point of its rotation about the rotation axis, or if the ground speed of the agricultural implement becomes zero or negative.

[0045] According to a fifth aspect, there is provided a straw harrow tine comprising a mounting portion, a working portion, and a spring portion, providing a torsion axis, such that the working portion is resiliently movable relative to the mounting portion, wherein the mounting portion extends non-tangentially out of the spring portion, and wherein the mounting portion and the working portion extend from the spring portion at angles with respect to the torsion axis which differ by less than 60 degs. A "straw harrow tine" is sometimes referred to as a "spring tine".

[0046] The mounting portion extending "non-tangentially out of the spring portion" implies that the mounting portion is bent further outwardly than what would be the case if it was merely bent out to be tangential.

[0047] The angles with respect to the torsion axis are in a plane that is perpendicular to the torsion axis.

[0048] The straw harrow tine as defined is capable of being mounted with the spring portion recessed into a supporting body, which may be fixed or movable, while allowing for a substantial deflection of the working portion.

[0049] The working portion may comprise a concave portion which is inwardly concave towards the mounting portion, and a convex portion, arranged radially outwardly of the concave portion, which is bent in a direction opposite of a bending direction of the concave portion.

[0050] The concave portion may be situated closer to the spring portion than the convex portion, as seen along the working portion.

[0051] The working portion comprises a first straight portion connecting the concave portion and the convex portion.

[0052] The working portion may comprise a second straight portion, arranged radially outwardly of the convex portion.

[0053] The first and second straight portions may extend in a common plane.

[0054] The first and second straight portions may extend in respective directions which form an angle of about 90-140 degs, preferably 100-130 degs.

[0055] The spring portion may comprise at least one helical portion.

[0056] The helical portion may present the torsion axis, which may be approximately perpendicular to the common plane. Hence, the torsion axis may coincide with a central axis of the helix.

[0057] The mounting portion, the working portion and the spring portion may present a substantially constant cross section.

[0058] The mounting portion, the working portion and the spring portion may be formed from a single piece of material, in particular a metal wire.

[0059] The mounting portion may be bent radially outwardly from the spring portion through at least 70 degs, preferably at least 90 degs or at least 100 degs, in particular 110-130 degs relative to a tangent of the spring portion where the mounting portion connects to the spring portion.

[0060] The mounting portion may extend non-tangentially from the spring portion, in the sense that a first tangent of the mounting portion taken closest to the spring portion, intersects the spring portion, as seen in a plane that is perpendicular to the torsion axis.

[0061] The mounting portion may be concave and the working portion may comprise a concave portion, wherein an angle difference between tangents taken along a radius of the mounting portion at the mounting portion and at the working portion diminishes in a direction away from the spring portion.

[0062] The angle difference, at a radius taken closest to the spring portion may be less than 60 degs.

[0063] The angle difference, at a radius taken farthest from the spring portion may be less than 40 degs.

[0064] The straw harrow tine may comprise the mounting portion, a first spring portion and a first working portion arranged on a first side of the mounting portion and a second spring portion and a second working portion arranged on a second side of the mounting portion.

[0065] The first and second spring portions may provide cylindrical torsion springs, spring axes of which being approximately parallel, and optionally approximately coinciding.

[0066] The first spring portion and the first working portion may be symmetrically arranged relative to the second spring portion and the second working portion.

[0067] The first and second working portions may diverge.

[0068] The first and second working portions may extend parallel with each other.

[0069] Fig. 1 is a schematic perspective view of a front portion of an agricultural implement 1.

[0070] Fig. 2 is a schematic side view of the agricultural implement 1.

[0071] Fig. 3 is a schematic perspective view of a straw harrow 100.

[0072] Fig. 4 is a schematic top view of the straw harrow 100.

[0073] Fig. 5 is a schematic side view of the straw harrow 100. Fig. 6a is a schematic side view of the rotatable part of the straw harrow 100.

[0074] Fig. 6b is a schematic side view corresponding to fig. 6b, illustrating a maximum deflection of one of the straw harrow tines.

[0075] Fig. 7a is a schematic partial exploded perspective view of the straw harrow 100.

[0076] Fig. 7b is a schematic perspective view of the straw harrow tine attachment.

[0077] Figs 8a-8b schematically illustrate a straw harrow tine.

[0078] Fig. 9 schematically illustrates an alternative agricultural implement.

[0079] Detailed description

[0080] Figs 1 and 2 schematically illustrates an agricultural implement 1 having an implement frame 10, 11, 12, 13, 14, 15, a traction vehicle connector 161, one or more ground supports 15, 121, 131, 141, and at least one set of soil working tools 111. The agricultural implement is configured to operate in a predetermined working direction Dw, which is a direction that is generally horizontal and parallel with soil surface.

[0081] The implement frame 10, 11, 12, 13, 14, 15 may be designed in a variety of ways, with some non-limiting examples being mentioned below.

[0082] Most frames will include longitudinally extending frame members, which extend substantially along the working direction Dw, and transverse frame members, which extend substantially across, such as perpendicular to, the working direction Dw. In the case of a towed implement, such as the one illustrated in figs 1 and 2, there may also be provided a draw bar 16 with the traction vehicle connector 161 provided at its distal end.

[0083] As a first example, the implement frame may be designed as a single, fixed and non-folding frame section.

[0084] As a second example, the implement frame may be designed with two frame sections, of which one or both may be foldable between e.g. a working position and a transport position. The frame sections may be configured in a side by side arrangement, with folding axis being substantially horizontal and parallel with the working direction Dw.

[0085] As a third example, the implement frame may be designed with three frame sections, of which one or two may be foldable between e.g. a working position and a transport position. The frame sections may be configured in a side by side arrangement, with folding axis / axes being substantially horizontal and parallel with the working direction Dw.

[0086] As a fourth example, the implement frame may be designed with four frame sections, of which three or four may be foldable between e.g. a working position and a transport position. The frame sections may be configured in a side by side arrangement, with folding axis / axes being substantially horizontal and parallel with the working direction Dw.

[0087] As a fifth example, the implement frame may be designed with five frame sections, of which four or all, may be foldable between e.g. a working position and a non-active position, such as a transport position. The frame sections may be configured in a side by side arrangement, with folding axis / axes being substantially horizontal and parallel with the working direction Dw.

[0088] In addition to the side-by-side frame arrangements mentioned above, each lateral frame section may be provided with one or more front frame sections, which may be foldable, or at least adjustable, relative to its associated lateral frame section, and which may be foldable with the lateral frame section, as the case may be. Such folding axis may be horizontal and substantially perpendicular to the working direction Dw.

[0089] In addition to the side-by-side frame arrangements mentioned above, each lateral frame section may be provided with one or more rear frame sections, which may be foldable relative to the lateral frame section and which may be foldable with the lateral frame section, as the case may be. Such folding axis may be horizontal and substantially perpendicular to the working direction Dw.

[0090] In the present example, the agricultural implement is designed with a longitudinally extending main frame 10, to which may be movably connected one or more first tool-carrying subframes 11, each of which carries a plurality of soil working tools 111, and which may be height adjustable relative to the main frame 10 by means of a first subframe actuator 112.

[0091] The subframe 11 may also be foldable relative to the main frame 10, such as between a working state and a transport state. Such folding may be controlled by a fold actuator 113. The set of soil working tools 111 may be mounted to one or more of the frame sections, in particular such that each tool operates in one row with little or no overlap with rows operated in by adjacent tools. Tools operating in immediately adjacent rows may be longitudinally spaced from each other along the working direction Dw, such that the risk of blockage of the agricultural implement is reduced.

[0092] The tools 111 may be resiliently mounted to the frame 10, 11, such that they can yield and return to their working position in the event an obstacle is struck.

[0093] The main frame 10 may also be height adjustable, e.g. between a working state and a headland-state, where all tools are raised from soil engagement so as to facilitate turning. To this front ground support 121 may be carried by a front support frame 12, which may be adjustable by means of a front actuator 122.

[0094] The tools 111 may thus be adjustable with respect to height relative to the implement frame and / or the implement frame may be height adjustable relative to the ground.

[0095] The agricultural implement 1 may be connectable to a traction vehicle by the draw bar 16, such that the agricultural implement 1 is towed by the traction vehicle.

[0096] Alternatively, the agricultural implement may be connectable to a traction vehicle by a two- or three-point hitch, such that the agricultural implement may be wholly or partially carried by the traction vehicle.

[0097] The agricultural implement may comprise one or more ground supports, such as wheels and / or packing rollers.

[0098] A further set of tools may optionally be arranged forwardly of the set of soil working tools as seen in the working direction Dw. Examples of such tools may be levelling tools, mixing tools or cutting tools. Such further set of tools may be mounted on the same frame section as the set of soil working tools, or on one or more front frame sections.

[0099] In the illustrated example, there is provided such a front frame section in the form of a straw harrow section 100.

[0100] Alternatively, or additionally, another further set of tools 131 may optionally be arranged rearwardly of the set of soil working tools 111 and optionally carried by a second subframe 13, which may be height adjustable relative to the main frame 10 by means of a third actuator 132. Examples of such tools may be reconsolidating tools, packing tools, planting or seeding devices, fertilizer or pesticide dispensing devices or further straw harrows.

[0101] A rear ground support 141, such as one or more wheels or rollers, may optionally be supported by a third subframe 14, which may be height adjustable relative to the main frame 10 by means of a fourth actuator 142.

[0102] Hence, the actuators 122, 142 may be operated in connection with the raising and lowering of the entire agricultural implement, such as in connection with a turn on a headland, or otherwise when it is desirable to disengage all tools from the soil.

[0103] The traction vehicle may be a traditional wheeled or tracked tractor, which may be manually or robotically controlled, or a gantry type traction vehicle which may be configured to carry and / or tow the agricultural implement 1.

[0104] Alternatively, the agricultural implement may be integrated with the traction vehicle.

[0105] The agricultural implement may be a cultivator-type implement or a harrowtype implement. However, it is also possible to provide the agricultural implement in the form of a seeder or a planter, in particular a precision planter.

[0106] Referring to figs 3-5, there is illustrated a schematic perspective view of the straw harrow section 100. In the illustrated example, the straw harrow section 100 comprises a straw harrow subframe 101, which may be adjustably mounted to the implement frame, e.g. such that it may be raised or lowered as desired.

[0107] The straw harrow section's subframe 101 may be height adjustable relative to the main frame 10 by means of an actuator 105.

[0108] It is possible to provide the straw harrow section 100 with one or more support wheels (not shown), which may be used to maintain a predetermined distance from the ground to the supporting body 102.

[0109] A straw harrow supporting body 102 is rotatably mounted to the straw harrow subframe 101, such that an rotation axis Ar of the straw harrow supporting body 102 extends substantially horizontally and transversely, such as perpendicular, to the working direction Dw.

[0110] The straw harrow supporting body 102 carries a plurality of straw harrow tines 1021, which extend generally radially and or tangentially outwardly from the straw harrow supporting body 102. A drive unit 104 is provided for causing the straw harrow supporting body 102 to rotate relative to the straw harrow subframe 101, in particular at an angular velocity that causes the radially outermost parts of the straw harrow tines 1021, when situated below the axis of rotation, and in particular at their lowermost point of a rotation turn, to provide a velocity relative to the ground over which the agricultural implement travels that corresponds to approximately 10-40 %, in particular 10-15 %, 15-20 %, 20-25 %, 25-30 %, 30-35 % or 35-40 %, of the velocity relative to the ground at which the agricultural implement travels along the working direction Dw.

[0111] The rotational velocity of the supporting body 102 may be adjustable to maintain a predetermined velocity ratio between the agricultural implement and the supporting body 102.

[0112] Preferably, the relative velocity may be adjustable, e.g. to accommodate for variations in the amount of crop residues present on the field.

[0113] It is possible to provide a sensor for detecting the amount of crop residues present, such that the relative velocity may be automatically adjusted.

[0114] Hence, the drive unit 104 may be configured to cause the straw harrow supporting body 102 to rotate in a rotation direction R, along with the working direction Dw, but at a lower velocity, such that the straw harrow will pick up crop residues to slowly release them as the agricultural implement travels across the field.

[0115] Consequently, a rotation vector ("right hand rule") of the supporting body 102 can be said to extend across the working direction, concentrically with the rotation axis Ar, and from left to right, e.g. as seen in fig 4, 6a-6b.

[0116] To this end, the drive unit 104 may be controlled to provide a rotation of the straw harrow supporting body 102 that is proportional to the velocity at which the agricultural implement travels along the working direction Dw.

[0117] The drive motor 104 may comprise an electric or hydraulic motor 1041 as well as a transmission 1042.

[0118] Alternatively, a brake device (not shown) may be used , whereby the rotation of the supporting body 102 is braked so as to be lower than the ground speed of the agricultural implement. Such a brake device may act directly on the supporting body 102 or via a transmission. In particular, the transmission 1042 may comprise a worm wheel type transmission, which is advantageous for limiting the forward speed of the straw harrow supporting body 102 to that provided by the drive unit 104. The threaded worm gear may be connected to the motor and a toothed wheel may be connected to the rotatable straw harrow supporting body 102.

[0119] By providing a worm wheel type transmission 1042 with an appropriate gear ratio, it is possible to provide a self-locking function, such that external forces that would cause the supporting body 102 to rotate are not transferred to the drive unit 104.

[0120] Referring to fig. 7a, the transmission 1042 may be combined with a freewheel 103, which may be configured to allow the straw harrow supporting body 102 to rotate freely in a direction opposite to a drive direction.

[0121] The freewheel 103 may be mounted between an output of the transmission 1042 and a drive shaft 1024 that is fixedly connected to the straw harrow supporting body 102. For example, an auxiliary drive sleeve 1043 may be provided for releasable connection between the drive shaft 1024 and the freewheel 103. A cover plate 1044 may cover the freewheel 103 and a fastener 1042, such as a nut, may fixate the cover plate, the freewheel 103 and the auxiliary drive sleeve 1043 to the drive shaft 1024.

[0122] Where a braking device is used, the freewheel may be mounted between the supporting body 102 and the braking device, such that the braking device may be disconnected when the agricultural implement is reversed or suddenly stopped, so as to protect the brake device.

[0123] The straw harrow subframe 101 is not essential, as the straw harrow supporting body 102 may instead be carried (i.e. rotatably mounted) by the implement frame.

[0124] Referring to figs 6a-6b, there is illustrated a side view of the straw harrow supporting body 102 and three straw harrow tines 1021a, 1021b, 1021c.

[0125] In the illustrated example, each straw harrow tine 1021a, 1021b, 1021c may be formed of a resiliently flexible elongate member, such as a metal wire, in particular of spring steel, and comprises a mounting portion 10211 for mounting of the straw harrow tine 1021a, 1021b, 1021c to the straw harrow supporting body 102; a spring portion 10212; and a working portion 10213, 10214, 10215, 10216, 10217 comprising an outer portion 10217, which presents a free end of the straw harrow tine 1021a, 1021b, 1021c and which, during operation of the straw harrow, interacts with the straw and soil.

[0126] The straw harrow supporting body 102 may be formed as a straight, elongate member, which may have a constant cross section. In particular, the straw harrow supporting body 102 may be formed from a metal tube, which may have a closed cross section, such as an oval, circular or polygonal cross section.

[0127] As a non-limiting example, a circular hollow tube having a diameter of about 100-150 mm may be used to provide a supporting body 102 having a width of up to about 3-3.5 m.

[0128] The straw harrow supporting body 102 may be formed with a plurality of openings or radial recesses 1022, which are sized and adapted for receiving at least part of the spring portion 10212 of at least some of the straw harrow tines 1021a, 1021b, 1021c. In the case where the straw harrow supporting body 102 is formed from a metal tube, it is, as a non-limiting example, possible to provide recesses 1022 in the form of cut-outs by means of laser cutting. Other cutting and / or drilling methods can also be used.

[0129] Turning to the description of the straw harrow tines, it is to be noted that, unless stated differently, the straw harrow tines are describe in an unbiased state, i.e. where they are not subjected to any external forces.

[0130] The mounting portion 10211 may comprise one or more bends, holes, loops, or the like, suitable for fastening the straw harrow tine 1021a, 1021b, 1021c to the straw harrow supporting body 102.

[0131] Optionally, an additional piece of material may be attached to the straw harrow tine 1021a, 1021b, 1021c for providing the mounting portion 10211.

[0132] Alternatively, or additionally, a clamping device 1023 may be provided for clamping the mounting portion 10211 to the straw harrow supporting body 102.

[0133] The mounting portion 10211 may be curved, such that it is inwardly concave towards the supporting body 102, with a bending radius that approximately corresponds to a curvature radius of the supporting body 102. A curvature radius Rc of the mounting portion 10211 may, as non-limiting examples, be about 50-70 mm, in particular 55-65 mm. The spring portion 10212 may, as illustrated, be provided as one or more turns of substantially helically configured portions of the elongate member, e.g. so as to provide a cylindrical or conical coil spring which is operational in torsional mode about a torsion axis At that is approximately parallel with the rotation axis Ar. However, other configurations for achieving a portion with resilient characteristics can be provided.

[0134] Referring to fig. 8a, the mounting portion 10211 may extend non-tangentially from the spring portion 10212, in the sense that a tangent T1 of the mounting portion taken closest to the spring portion 10212, intersects the spring portion 10212, as seen in a plane that is perpendicular to the torsion axis At.

[0135] The mounting portion 10211 may be formed in one piece with the spring portion and may be bent through at least about 70 degs, preferably at least about 100 degs, relative to a tangent TO at a position where the mounting portion 10211 connects to the spring portion 10212. In the illustrated example, the mounting portion 10211 is bent through about 120 degs, such that its innermost portion has a tangent T1 that is about 120 degs to the tangent TO, as seen in a plane perpendicular to the torsion axis At.

[0136] An inner portion 10213 of the working portion may extend tangentially from the spring portion 10212, in the sense that a tangent T2 of the inner portion 10213 closest to the spring portion 10212 is tangential to the spring portion 10212.

[0137] Moreover, with regard to the mounting portion 10211 a first angle difference between the mounting portion tangent T1 closest to the spring portion 10212 and a corresponding tangent T3 taken at the inner portion 10213, or at the concave portion 10214, along a first common radius rl with respect to the curvature radius Rc of the mounting portion 10211 may be less than about 60 degs, preferably about 10-60 degs, in particular about 10-20 degs, about 20-30 degs, about 30-40 degs, about 40-50 degs or about 50-60 degs. In the illustrated example, the first angle difference is about 35 degs.

[0138] A corresponding second angle difference between a mounting portion tangent T4, farthest from the spring portion 10212 and a corresponding tangent T5 taken at the inner portion 10213, or at the concave portion 10214, along a second common radius r2 with respect to the curvature radius Rc of the mounting portion 10211 may be about less than the angle difference defined above and preferably less than 40 degs, in particular about 10-20 degs, 20-30 degs or 30-40 degs. In the illustrated example, the second angle difference is about 25 degs.

[0139] Hence, the angle difference may diminish as the angular distance to the spring portion increases. From the spring portion 10212, the straw harrow tine 1021a, 1021b, 1021c may extend radially and / or tangentially outwardly from the straw harrow supporting body 102 in a variety of configurations, such as straight or curved.

[0140] In the illustrated embodiment, each straw harrow tine 1021a, 1021b, 1021c may comprise an inner portion 10213 which extends approximately tangentially from the straw harrow supporting body 102 and which via a curved first transition portion, which may be an essentially inwardly concave portion 10214, transforms to a first straight portion 10215, which extends along a direction that is between the tangential direction and a radial direction, as seen in a plane perpendicular to the rotation axis Ar.

[0141] In particular, the inner portion 10213 may extend from a point on the spring portion 10212, where the inner portion tangents a cylindrical body of the spring portion, as seen in a plane perpendicular to a torsion axis of the spring portion 10212. This inner portion may be straight, or slightly inwardly concave as seen in said plane.

[0142] The first transition portion 10214 may provide a curvature which is concave towards the straw harrow supporting body 102.

[0143] The first straight portion 10215 may extend at a first angle Al of about 70-90 degs, preferably about 75-85 degs, to the radial direction of the supporting body 102.

[0144] The first straight portion 10215 may extend at an angle A4 to a tangent taken where the inner portion 10213 tangents the spring portion 10212, which may be about 70-110 degs, preferably about 80-100 degs or about 85-95 degs.

[0145] The first straight portion 10215 may be spaced from the spring portion by at least one of the inner portion 10213 and the concave portion 10214.

[0146] Outwardly of the first straight portion 10215, there may be provided a second transition portion 10216, at which the straw harrow tine 1021a, 1021b, 1021c transforms into a second straight portion, which may form the outer portion The second transition portion 10216 may provide a curvature which is convex towards the straw harrow supporting body 102.

[0147] The second straight portion 10217 may extend at a second angle A2 of about 10-40 degs, preferably about 20-30 degs, to the radial direction.

[0148] The second straight portion 10217 may have a length which may be about 30-70 % of length of the first straight portion 10215.

[0149] The first and second straight portions 10215, 10217 may define a plane which is approximately perpendicular to a torsion axis of the spring portion 10212.

[0150] The entire working portion 10213, 10214, 10215, 10216, 10217 of the straw harrow tine may be situated in this plane.

[0151] The first and second straight portions 10215, 10217 may extend in respective directions which form an angle of about 90-140 degs, preferably about 100-130 degs.

[0152] Straw harrow tines 1021a, 1021b, 1021c may be formed from a metal wire, in particular of so-called "spring steel", having a substantially constant cross section, which may be curved, such as oval or circular, with a major diameter of about 4-9 mm, preferably of about 6-8 mm, and in particular of about 7 mm.

[0153] As is illustrated in fig. 6b, the design of straw harrow tines with the spring portion 10212, the inner portion 10213 and the first transition portion 10214 as described above enables the straw harrow tines 1021a, 1021a' to deflect in the rotation direction R such that their tips may move through an angle of about 40-50 degs about the rotation axis Ar.

[0154] Straw harrow tines 1021a, 1021b, 1021c may be formed as individual tines, or as "dual tines", wherein each tine comprises a pair of outer portions 10217, which may be mutually symmetrical.

[0155] Fig. 7b provides a detailed schematic view of a dual tine, comprising a first tine portion 1021-1, a second tine portion 1021-2 and a common mounting portion 10211, which may be integrally formed from a single piece of material. A first spring portion 10212-1 is associated with the first tine portion 1021-1 and a second spring portion 10212-2 is associated with the second tine portion 1021-2. Both spring portions 10212-1, 10212-2 may be recessed into the recess 1022 in the supporting body 102. The spring portions 10212-1, 10212-2 and tine portions 1021-1, 1021-2 may be symmetric about a plane that is perpendicular to the rotation axis Ar and which extends through a center of the mounting portion 10211, as seen along the rotation axis Ar.

[0156] Each tine portion 1021-1, 1021-2 may be designed in accordance with what was discussed with reference to figs 6a-6b.

[0157] Hence, while the mounting portion 10211 of each straw harrow tine 1021a, 1021b, 1021c may interact with a surface of the straw harrow supporting body 102, at least some of the spring portions 10212 of at least some of the straw harrow tines 1021a, 1021b, 1021c will, when mounted to the straw harrow supporting body 102, be received in such recesses 1022.

[0158] For example, where the spring portion 10212 comprises at least one turn of a helically configured portion of a straw harrow tine 1021a, 1021b, 1021c, some 20-80 %, preferably 30-70 % or 40-60 %, of the spring portion 10212 may be recessed into the straw harrow supporting body 102, assuming that the a winding axis of the spring portion 10212 is essentially parallel with the rotation axis Ar.

[0159] As is illustrated in fig. 8b, the working portions of the tine portions 1021-1, 1021-2 may diverge from each other, as seen in a plane comprising the torsion axis At of the spring portions.

[0160] Referring to fig. 9, there is schematically illustrated an agricultural implement in the form of a dedicated straw harrow having two straw harrow sections 100a, 100b arranged one after the other as seen in the working direction Dw. Such an agricultural implement may have one, two or more laterally arranged sections that may be foldable relative to each other, as described above.

[0161] Operation of straw harrows as described above is particularly advantageous when the working direction is at an oblique angle, in particular of about 20-70 degs, relative to a direction along which the straw ridges formed by a harvester extend.

Claims

CLAIMS1. An agricultural implement (1), comprising an implement frame (10, 11, 12, 13, 14, 101) and a straw harrow (100), the straw harrow (100) comprising: a supporting body (102), which is rotatably mounted relative to the implement frame (10, 11, 12, 13, 14, 101) about a rotation axis (Ar), and which supports a plurality of straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021- 2) projecting generally radially and / or tangentially outwardly from the supporting body (102), wherein at least some of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) comprise a mounting portion (10211), a working portion (10213, 10214, 10215, 10216, 10217) and a spring portion (10212), such that the working portion (10213, 10214, 10215, 10216, 10217) is resiliently movable relative to the mounting portion (10211), characterized in that the spring portion (10212) is at least partially recessed into the supporting body (102).

2. The agricultural implement as claimed in claim 1, wherein the spring portion (10212) comprises at least one helical portion.

3. The agricultural implement as claimed in claim 1 or 2, wherein at least part of the working portion (10213, 10214, 10215, 10216, 10217) extends from the spring portion (10212) in a direction which is substantially tangential relative to the rotation axis (Ar).

4. The agricultural implement as claimed in any one of the preceding claims, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a concave portion (10214) which is inwardly concave towards the rotation axis (Ar).

5. The agricultural implement as claimed in claim 4, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a convex portion (10216),arranged radially outwardly of the concave portion (10214), which is inwardly convex towards the rotation axis (Ar).

6. The agricultural implement as claimed in claim 5, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a first straight portion (10215) connecting the concave portion (10214) and the convex portion (10216).

7. The agricultural implement as claimed in claim 6, wherein the first straight portion (10215) extends at an angle (Al) of about 70-90 degs, preferably about 75-85 degs relative to a radial direction from the rotation axis (Ar).

8. The agricultural implement as claimed in any one of claims 5-7, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a second straight portion (10217), arranged radially outwardly of the convex portion (10216).

9. The agricultural implement as claimed in claim 8, wherein the second straight portion (10217) extends at an angle (A2) of about 10-40 degs, preferably about 20-30 degs, relative to a radial direction from the rotation axis (Ar).

10. The agricultural implement as claimed in any one of the preceding claims, wherein the mounting portion (10211), the working portion (10213, 10214, 10215, 10216, 10217) and the spring portion (10212) present a substantially constant cross section.

11. The agricultural implement as claimed in any one of the preceding claims, wherein the mounting portion (10211), the working portion (10213, 10214, 10215, 10216, 10217) and the spring portion (10212) are formed from a single piece of material, in particular a metal wire.

12. The agricultural implement as claimed in any one of the preceding claims, wherein the supporting body (102) has a closed cross section, such as a circular cross section.

13. The agricultural implement as claimed in any one of the preceding claims, further comprising a drive motor (1041), for rotatably driving the supporting body (102), or a brake device, for braking the a rotation of the supporting body (102).

14. The agricultural implement as claimed in claim 13, further comprising a transmission (1042) operatively connecting the drive motor (1041), or the braking device, to the supporting body (102).

15. The agricultural implement as claimed in claims 14, wherein the transmission (1042) is configured such that when advancing the agricultural implement (1) along a working direction (Dw), the supporting body (102) is caused to rotate in a forward direction (R), such that radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2), when positioned at a lowermost point of its rotation about the rotation axis (Ar), have a ground speed that is lower than that of the implement frame (10, 11, 12, 13, 14, 101) but greater than zero.

16. The agricultural implement as claimed in claim 14 or 15, wherein the transmission comprises a worm gear having a toothed wheel fixedly connected to the supporting body (102) and a spiral thread wheel fixedly connected to the drive motor (1041).

17. The agricultural implement as claimed in any one of claims 14-16, further comprising a freewheel (1044) configured to disengage the drive motor (1041) or brake device from the supporting body (102) when a forward travel velocity of the agricultural implement (1) is less than a forward velocity of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar).

18. The agricultural implement as claimed in claim 13 or 14, wherein the transmission is configured such that when advancing the agricultural implementalong a working direction, the supporting body is caused to rotate in a forward direction, such that radially outermost portions of the straw harrow tines, while positioned below the axis of rotation, have a ground speed that is lower than that of the implement frame but greater than zero.

19. The agricultural implement as claimed in any one of the preceding claims, wherein, when one of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) is at a lowermost point of its rotation about the rotation axis (Ar), the convex portion (10216) is rearwardly convex relative to the working direction (Dw).

20. An agricultural implement (1), comprising an implement frame (10, 11, 12, 13, 14, 101) and a straw harrow (100), the straw harrow (100) comprising: a supporting body (102), which is rotatably mounted relative to the implement frame about a rotation axis (Ar) and which supports a plurality of straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) projecting generally radially outwardly from the supporting body (102), a drive motor (1041), for driving the supporting body (102), and a transmission (1042) for operatively connecting the drive motor (1042) to the supporting body (102), characterized in that the transmission (1042) comprises a worm gear having a toothed wheel fixedly connected to the supporting body (102) and a spiral thread wheel fixedly connected to the drive motor (1041).

21. The agricultural implement as claimed in claim 20, further comprising a freewheel (1044) configured to disengage the drive motor (1041) from the supporting body (102) when a forward travel velocity of the agricultural implement (1) is less than a forward velocity of radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar).

22. The agricultural implement as claimed in claim 20 or 21, wherein the transmission (1042) is configured such that when advancing the agricultural implement (1) along a working direction (Dw), the supporting body (102) is caused to rotate in a forward direction (R), such that radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar), have lower ground speed than the implement frame (10, 11, 12, 13, 14, 101).

23. An agricultural implement (1), comprising an implement frame (10, 11, 12, 13, 14, 101) and a straw harrow (100), the straw harrow (100) comprising: a supporting body (102), which is rotatably mounted relative to the implement frame (10, 11, 12, 13, 14, 101) about a rotation axis (Ar) and which supports a plurality of straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021- 2) projecting generally radially outwardly from the supporting body (102), a drive motor (1041), for driving the supporting body (102), or a brake device for braking a rotation of the supporting body (102), and a freewheel configured to disengage the drive motor (1041) or braking device from the supporting body (102) when a forward travel velocity of the agricultural implement (1) is less than a forward velocity a radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar).

24. The agricultural implement as claimed in claim 23, further comprising a transmission (1042) for connecting the drive motor (1041) or braking device to the supporting body (102).

25. The agricultural implement as claimed in claim 24, wherein the transmission (1042) is configured such that when advancing the agricultural implement (1) along a working direction (Dw), the supporting body (102) is caused to rotate in a forward direction (R), such that radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar), have lower ground speed than the implement frame (10, 11, 12, 13, 14, 101).

26. The agricultural implement as claimed in any one of the preceding claims, wherein the rotation axis (Ar) extends substantially horizontally.

27. The agricultural implement as claimed in any one of the preceding claims, wherein the rotation axis (Ar) extends substantially horizontally and transversely to a working direction (Dw) of the agricultural implement.

28. A method of operating an agricultural implement, comprising an implement frame (10, 11, 12, 13, 14, 101) and a straw harrow, the straw harrow comprising: a supporting body, which is rotatably mounted relative to the implement frame (10, 11, 12, 13, 14, 101) about a rotation axis (Ar) and which supports a plurality of straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) projecting generally radially and / or tangentially outwardly from the supporting body, wherein at least some of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) comprise a mounting portion, a working portion (10213, 10214, 10215, 10216, 10217) and a spring portion (10212), such that the working portion (10217) is resiliently displaceable relative to the mounting portion (10211), the method comprising: causing the agricultural implement (1) to move in a working direction (Dw) at a predetermined ground speed, while causing the agricultural implement (1) to move in the working direction (Dw) at the predetermined ground speed, using a drive motor (1041) or a braking device to cause the supporting body (102) to rotate such that radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) when positioned at a lowermost point of its rotation about the rotation axis (Ar), have a ground speed that is lower than that of the implement frame (10, 11, 12, 13, 14, 101) but greater than zero, and causing the supporting body (102) to be mechanically disconnected from the drive motor (1041) in the event the ground speed of the agricultural implement (1) falls below that the ground speed of the radially outermost portions (10217) of each of the straw harrow tines (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2), whenpositioned at a lowermost point of its rotation about the rotation axis (Ar), or if the ground speed of the agricultural implement (1) becomes zero or negative.

29. A straw harrow tine (1021, 1021a, 1021b, 1021c, 1021-1, 1021-2) comprising: a mounting portion (10211), a working portion (10213, 10214, 10215, 10216, 10217), and a spring portion (10212), providing a torsion axis (At), such that the working portion (10213, 10214, 10215, 10216, 10217) is resiliently movable relative to the mounting portion (10211), wherein the mounting portion extends non-tangentially out of the spring portion, and wherein the mounting portion and the working portion extend from the spring portion at angles with respect to the torsion axis which differ by less than 60 degs.

30. The straw harrow tine as claimed in claim 29, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises: a concave portion (10214) which is inwardly concave towards the mounting portion (10211), and a convex portion (10216), arranged radially outwardly of the concave portion (10214), which is bent in a direction opposite of a bending direction of the concave portion (10214).

31. The straw harrow tine as claimed in claim 29 or 30, wherein the concave portion is situated closer to the spring portion than the convex portion, as seen along the working portion.

32. The straw harrow tine as claimed in any one of claims 29-31, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a first straight portion (10215) connecting the concave portion (10214) and the convex portion (10216).

33. The straw harrow tine as claimed in any one of claims 29-32, wherein the working portion (10213, 10214, 10215, 10216, 10217) comprises a second straight portion (10217), arranged radially outwardly of the convex portion (10216).

34. The straw harrow tine as claimed in claim 33, wherein the first and second straight portions (10215, 10217) extend in a common plane.

35. The straw harrow tine as claimed in claim 34, wherein the first and second straight portions (10215, 10217) extend in respective directions which form an angle of about 90-140 degs, preferably 100-130 degs.

36. The straw harrow tine as claimed in any one of claims 29-35, wherein the spring portion (10212) comprises at least one helical portion.

37. The straw harrow tine as claimed in claim 36, wherein the helical portion presents the torsion axis, which is approximately perpendicular to the common plane.

38. The straw harrow tine as claimed in any one of claims 29-37, wherein the mounting portion (10211), the working portion (10213, 10214, 10215, 10216, 10217) and the spring portion (10212) present a substantially constant cross section.

39. The straw harrow tine as claimed in any one of claims 29-38, wherein the mounting portion (10211), the working portion (10213, 10214, 10215, 10216, 10217) and the spring portion (10212) are formed from a single piece of material, in particular a metal wire.

40. The straw harrow tine as claimed in claim 39, wherein the mounting portion is bent radially outwardly from the spring portion (10212) through at least 70 degs, preferably at least 90 degs or at least 100 degs, in particular 110-130 degs relative to a tangent of the spring portion (10212) where the mounting portion (10211) connects to the spring portion.

41. The straw harrow tine as claimed in any one of claims 29-40, wherein the mounting portion (10211) extends non-tangentially from the spring portion (10212), in the sense that a first tangent (Tl) of the mounting portion taken closest to the spring portion (10212), intersects the spring portion (10212), as seen in a plane that is perpendicular to the torsion axis (At).

42. The straw harrow tine as claimed in claim 41, wherein the mounting portion (10211) is concave and wherein the working portion comprises a concave portion, wherein an angle difference between tangents (Tl, T3; T4, T5) taken along a radius of the mounting portion at the mounting portion (10211) and at the working portion (10213, 10214, 10215, 10216, 10217) diminishes in a direction away from the spring portion (10212).

43. The straw harrow tine as claimed in claim 42, wherein the angle difference, at a radius (rl) taken closest to the spring portion (10212) is less than 60 degs.

44. The straw harrow tine as claimed in claim 42, wherein the angle difference, at a radius (r2) taken farthest from the spring portion (10212) is less than 40 degs.

45. The straw harrow tine as claimed in any one of claims 29-44, wherein the straw harrow tine comprises the mounting portion (10211), a first spring portion (10212-1) and a first working portion arranged on a first side of the mounting portion and a second spring portion (10212-2) and a second working portion arranged on a second side of the mounting portion (10211).

46. The straw harrow tine as claimed in claim 45, wherein the first and second spring portions (10212-1, 10212-2) provide cylindrical torsion springs, spring axes of which being approximately parallel, and optionally approximately coinciding.M . The straw harrow tine as claimed in claims 45 or 46, wherein the first spring portion (10212-1) and the first working portion are symmetrically arranged relative to the second spring portion (10212-2) and the second working portion.

48. The straw harrow tine as claimed in any one of claims 45-47, wherein the first and second working portions diverge.

49. The straw harrow tine as claimed in any one of claims 45-48, wherein the first and second working portions extend parallel with each other.

50. The straw harrow tine as claimed in any one of claims 29-49, wherein the angles with respect to the torsion axis are in a plane that is perpendicular to the torsion axis.

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