Harrow implement

Abstract

The present invention relates to an agricultural implement, in particular a harrow implement. In one aspect, there is provided an implement suitable for use as a harrow, the implement including: a. a bar adapted to support a plurality of spaced apart tines along the length of the bar, and b. a mounting for securing the bar directly or indirectly onto a towing vehicle, wherein said mounting incorporating a linkage assembly adapted to permit up-and-down movement of the bar; the linkage assembly connected at one end to a harrow bracket and at its other end to a drawbar bracket, each bracket configured and adapted to permit a limited arc of rotation independently of the other bracket, the plane of rotation of each bracket being substantially perpendicular to the length of the bar supporting the tines.

Description

[0001] HARROW IMPLEMENT

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an agricultural implement, in particular a harrow implement.

[0004] BACKGROUND

[0005] Many different types of harrow are available for use either as independent implements or in combination with other implements, such as seed drills. In a typical application, a spring-tine harrow or a chain harrow is used behind a seed drill (conventional or direct drill) to close the ground after the drill.

[0006] To function efficiently in smoothing the ground, the harrow should maintain a good firm contact with the ground at all times; this can be achieved either by spring-biasing the harrow into contact with the ground or by the weight of the harrow itself. However, if the harrow encounters obstacles in the soil, (e.g. large stones), the harrow must be able to move out of contact with the obstacle rather than snagging and possibly breaking. One such harrow is described in New Zealand Patent NZ 542203. One of the drawbacks with the harrow described in NZ 542203 is the harrow maintains contact firmly with the ground and if the vehicle towing the harrow goes uphill suddenly or rolls back suddenly the following harrow tines are forced into the ground and are very prone to snapping or breaking off. There is no ability to relieve the downward pressure on the tines.

[0007] Accordingly, it is an object of the present invention to provide a harrow implement suitable for use as a harrow which is capable of maintaining excellent contact with the ground even if the ground contours are irregular, but which can move out of contact with the ground as the vehicle towing the harrow moves into an uphill gradient or rolls backward without damage to the implement.

[0008] SUMMARY OF THE INVENTION

[0009] In one aspect, there is provided an implement suitable for use as a harrow, the implement including:

[0010] a. a bar adapted to support a plurality of spaced apart tines along the length of the bar, and

[0011] b. a mounting for securing the bar directly or indirectly onto a towing vehicle, said mounting incorporating a linkage assembly adapted to permit up-and-down movement of the bar; the linkage assembly connected at one end to a harrow bracket and at its other end to a drawbar bracket, each bracket configured and adapted to permit a limited arc of rotation independently of the other bracket, theplane of rotation of each bracket being substantially perpendicular to the length of the bar supporting the tines.

[0012] In one example, the linkage assembly includes a linkage bar that extends between the harrow bracket and the drawbar bracket.

[0013] In one example, the linkage assembly includes a linkage bar that extends between the harrow bracket and the drawbar bracket and a wire cable that extends between the harrow bracket and the drawbar bracket.

[0014] In one example, the linkage assembly further includes a biasing means connected to the harrow bracket, the biasing means biasing the harrow bracket towards the drawbar bracket, when in use. In one example, the biasing means is connected at one end to the linkage bar at a point intermediate the harrow bracket and the drawbar bracket and at the other end to the harrow bracket.

[0015] In one example, the linkage assembly is configured to allow the harrow bracket to independently rotate up to about 110 degrees relative to the drawbar bracket.

[0016] In one example, the linkage bar is an I-bar.

[0017] In one example, the harrow bracket and the drawbar bracket each comprise a pair of parallel flanges, arranged one on each side of the linkage bar of the linkage assembly, each of the flanges being pivotally connected to the linkage bar and wherein the pivotal movement is in a plane parallel to the longitudinal axis of the linkage bar.

[0018] In one example, the implement further includes a biasing means proximate the drawbar bracket that may be optionally actuated to increase the downward torque on the linkage assembly to increase the downward pressure on the tines, when in use.

[0019] Further aspects of the present invention will become apparent from the accompanying Figures and detailed description, which are provided by way of non-limiting example.

[0020] DESCRIPTION OF THE FIGURES

[0021] By way of example only, a preferred embodiment of the present invention is described in detail with reference to the accompanying Figures, in which:- Figure 1 shows a rear perspective view of one example of an implement having tines and a linkage assembly suitable for being towed behind a vehicle;

[0022] Figure 2 shows a top view of the implement shown in Figure 1;

[0023] Figure 3 shows a side view of the implement shown in Figures 1 and 2;Figure 4 shows a front-end perspective view of the implement shown in Figures 1 to 3 with the tines removed.

[0024] Figure 5 shows a side perspective view of the linkage assembly.

[0025] Figure 6 shows a side perspective view of the linkage assembly having one side of the harrow bracket and the drawbar bracket removed to show the components of the linkage assembly and showing the biasing means in a compressed state.

[0026] Figure 7 shows a side view of the implement shown in Figures 1 and 2 with the biasing means shown in a partially extended state;

[0027] Figure 8 shows a side view of the implement shown in Figure 7 with the biasing means shown in a further extended state;

[0028] Figure 9 shows a side view of the mounting arrangement of the tines to the bar.

[0029] Figure 10 shows a side view of a tension mechanism that is optionally added to the implement assembly to provide further adjustable tension on the harrow tines.

[0030] DETAILED DESCRIPTION

[0031] As used herein throughout the description and appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0032] As used herein throughout the description and the appended claims, the term "about" and "approximately" is intended to mean ± 10 % of the stated value.

[0033] As used herein, the term "substantially" is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially perpendicular includes perpendicular), as understood by a person of ordinary skill in the art. In any disclosed embodiment, the terms "substantially," "approximately," and "about" may be substituted with "within [a percentage] of what is specified, where the percentage includes 0.1, 1, 5, and 10 percent.

[0034] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising" and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

[0035] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.Referring to the accompanying Figures, an agricultural implement 1 consists of a rigid, straight bar 2 which carries a number of equidistantly spaced pairs of tines 3. The bar 2 is carried by a support bracket, hereinafter referred to as the harrow bracket 4.

[0036] The bar 2 may be of any suitable cross-sectional shape and may be hollow or solid. The length of the bar 2 may extend the full width of the implement, especially if the implement is relatively narrow; preferably, however, the whole implement comprises two or more bars 2, each bar being carried on its own harrow bracket 4. Typically, each bar is about 1 to 2 metres long.

[0037] Each Tine 3 is rigidly mounted to the bar 2 by a clamp 5 of known type. With reference to Figure 9, each Tine 3 is made of spring steel and includes a coiled portion 6, the free end 6a of which is clamped in the clamp 5. The other end 7 of the coiled portion 6 extends downwards at a small angle to the vertical and terminates in a long foot portion 8 or 9 which extends at a small angle to the horizontal and extends at an obtuse angle to the direction of movement of the implement in use. For each pair of tines 3, the foot 8 of one tine extends in the opposite direction to the foot of the other tine 9 (best seen in Figure 2).

[0038] Although the above described tines are believed to give optimum results for the implement, the implement described may also be used with any of a number of known types of straight tines or spring tines secured to the bar.

[0039] Referring in particular to Figs. 3 - 6, a linkage assembly 10 is shown that provides a linkage between the bar 2 and a towing vehicle (not shown). The linkage comprises a first or harrow bracket 4 and a second or drawbar bracket 11, the brackets being spaced apart by an I-bar 12. With reference to Figure 6, the I-bar 12 is mounted on its side, so that the I-bar 12 connects to each of the brackets 4 and 11 at a lower pivot connection point, 13 and 14 respectively and through an upper slot connection 15, 16 respectively on each bracket. Each upper slot connection 15 and 16 on each bracket allows the I-bar 12 to move in an arc relative to the corresponding fixed pivot point 13 and 14 of the I-bar 12 on the lower end of each bracket. The linkage assembly may further comprise a cable 17 that extends from the harrow bracket 4 to the drawbar bracket 11. Preferably the cable extends from the lower end of harrow bracket 4 to the lower end of drawbar bracket 11. Preferably, the cable is a wire cable.

[0040] The brackets 4, llwill be described in more detail. Each harrow bracket 4 includes flanges 18 and 19 which are mounted to each side of one end of the I-bar 12. Each drawbar bracket 11 includes spaced apart flanges 20 and 21 that are mounted to each side of the drawbar end of the I-bar 12. With reference to Figure 6, the I-bar 12 is pivotally attached to each bracket at each of the lowerends of the I-bar 12 at point 13 and 14 respectively. The connection is by way of a fastener of known type extending through the flange 19 (not shown in Figure 6), through the lower pivot point 13 of the I-bar 12 and then through the flange 18 on the other side of the I-bar 12. The fastener is configured to allow rotation of the I-bar 12 about the pivot point 13. At the upper end of the bracket 4 the connection to the I-bar 12 is an arcuate shaped slot 22a, 22b respectively cut through each flange 18 and 19 through which a fastener at the upper point 15 of the I-bar 12 extends. The connection is by way of a fastener of known type extending through the arcuate slot 22b on flange 19 (not shown in Figure 6), through the upper point 15 of the I-bar 12 and then through the arcuate slot 22a on flange 18 on the other side of the I-bar 12. Each arcuate slot 22a and 22b is configured to provide controlled and limited rotation of the top end of the I-bar 12 of up to about 50 degrees as illustrated about the upper point 15 relative to the lower pivot point 13 of the I-bar 12. Each arcuate slot 22a and 22b extends across the face of each flange 18 and 19 respectively. It is to be appreciated that the brackets could be configured to allow for greater degrees of rotation by extending the flanges and it is envisaged that up to about 110 degrees of rotation of the brackets, in particular the harrows bracket, could be achieved. It is to be appreciated that while the curved slots have been shown as regular arcs, it is further envisaged that these slots could also be further extended in a more linear direction towards the drawbar end of the assembly to allow the harrows to be raised up even further, for example when the harrows are being towed up hills.

[0041] The flanges 18 and 19 are kept in a spaced apart arrangement by the I-bar 12 and by the harrow bar mounting system 23 positioned proximate the lower edge of each flange. The mounting system 23 comprises cutouts in each of flanges 18 and 19 through which the harrow bar 2 can extend and flanges 24 and 25 that extend on either side of the harrow bar, parallel to the axis of the harrow bar 2 and between flanges 18 and 19. The flanges 18 and 19 are adapted to secure flanges 24 and 25 through cut out slots into which the flanges 24 and 25 are secured. When in use a fastener 26 passes through flange 24, the harrow bar 2 and the flange 25 on the other side of the harrow bar. The fastener 26 preferably has a threaded fastening shaft onto which a nut can be tightened to secure and mount the midpoint of the harrow bar (perpendicular to the longitudinal axis of the bar) to the bracket 4.

[0042] Each drawbar bracket 11 includes flanges 20 and 21 that are mounted to each side of the drawbar end of the I-bar 12. With reference to Figure 6, the I-bar 12 is pivotally attached to the draw bar bracket at the lower ends of the I-bar 12 at pivot point 14. The connection is by way of a threaded fastener extending through the flange 21 (not shown in Figure 6), through the lower pivot point 14of the I-bar 12 and then through the flange 20 on the other side of the I-bar 12. The fastener is configured to allow rotation of the I-bar 12 about the pivot point 14. At the upper end of the bracket 11 the connection to the I-bar 12 is an arcuate shaped slot 27a, 27b respectively cut through each flange 20 and 21 through which a fastener at the upper point 16 of the I-bar 12 extends. The connection is by way of a threaded fastener extending through the arcuate slot 27b on flange 21 (not shown in Figure 6), through the upper point 16 of the I-bar 12 and then through the arcuate slot 27a on flange 20 on the other side of the I-bar 12. Each arcuate slot 27a and 27b is configured to provide controlled and limited rotation of the top end of the I-bar 12 of about up to 50 degrees of rotation about the upper point 16 relative to the lower pivot point 14 of the I-bar 12. Each arcuate slot 27a and 27b extends across the face of each flange 20 and 21 respectively. The flanges 20 and 21 are kept in a spaced apart arrangement by the I-bar 12 and by the end plate 28 which is positioned between and connected proximate the draw bar end of the bracket 11. The endplate 28 is formed with a plurality of mounting holes (not visible) to enable the bracket to be supported on a towing vehicle or on another implement, using clamps, mounting bolts or other suitable attachment means.

[0043] The linkage assembly may further comprise a cable 17 that extends from the harrow bracket 4 to the drawbar bracket 11. Preferably the cable extends from beneath pivot point 13 at the lower end of harrow bracket 4 to beneath the pivot point 14 of the lower end of drawbar bracket 11. The cable is mounted to the flanges by way of a threaded fastener or such like (17a, 17b) that extends between the respective flanges on each bracket, as shown in Figures 6, 7 and 8.

[0044] The linkage assembly may further include a biasing means 29 linkage includes a biasing means connected at one end 29a intermediate the flanges of the harrow bracket 4 by a fastening means 30 that passes between the flanges 18 and 19. The biasing means is preferably connected at its other end 29b to the I-bar 12 bar at a point intermediate the harrow bracket and the drawbar bracket. Preferably, the biasing means 29 biases the harrow bracket 4 towards the drawbar bracket 11 when the biasing means is under tension. Preferably the biasing means 29 is a coil spring.

[0045] The above described implement is set out and operated as follows: - the complete implement is made up of one or more bars 2, each bar 2 being supported by its own harrow bracket, which is in turn connected to a drawbar bracket through the above described linkage assembly. Each drawbar bracket is secured to the rear of a towing vehicle or to the rear of another implement, (e.g. a seed drill). Each bar 2 is provided with its own set of tines 3, mounted as described above. The implement is then towed over the ground to be worked. The linkage assembly of each implement and the pivoting action permitted by each I-bar 12 allow each section of the implement to follow the groundcontours accurately, while also permitting sufficient movement of the implement that any tines 3 encountering an obstacle on the ground can rise over the obstacle without damage to the tines 3 or the implement.

[0046] Figures 1 to 6 all show the harrow bracket 4 and drawbar bracket 11 at their respective lowest rotational positions in their respective slots. In this position the harrow bar 2 remains parallel to the face plate of the draw bar bracket 11.

[0047] With reference to Figure 7 the harrow bracket 4 and drawbar bracket 11 are at their respective middle rotational positions in their respective slots. As the l-bar 12 raises through its rotational position it pulls the harrow bracket 4 forward and tightens the cable 17 keeping the harrow bar 2 parallel to the face plate of the draw bar bracket 11.

[0048] With reference to Figure 8, the independent rotation of the upper brackets about the I-bar 12 allows and enables release of tension on the tines 3 when the implement experiences a roll back event. In such an event, the cable 17 can slacken and allow the harrow bracket 4 to pivot independently to the drawbar bracket 11. The backwards force on the harrow bracket 4 overrides the biasing means / spring 29 and the harrow bracket 4 can undergo a controlled rotation through up to about 50 degrees. This independent rotation of the brackets helps to avoid damage to the tines and the linkage assembly caused by a towing vehicle rolling back, reversing or shifting into a steep uphill gradient.

[0049] With reference to Figure 10, a tension mechanism 31 that is optionally added to the implement assembly to provide further adjustable tension or torque on the harrow tines is shown. The mechanism 31 provides a locking handle 32 that is connected to a locking pin (not shown), which can be engaged into any one of a range of tension holes 33 to provide additional downward pressure or torque onto the tines 3. If the locking handle 32 and the locking pin are disengaged, the harrows can float along the ground surface under their own weight. The locking handle 32 extends to a pivot point 34 and then into a slot 35. The locking handle being connected to one end of a biasing means 36. The other end of the biasing means 36 is connected to a lever 37, which lever is pivotally connected to the lower end of the I-bar 12 at pivot point 14 proximate the drawbar mounting end of the assembly 1. Increasing the bias on the I-bar 12 at pivot point 14 forces the I-bar 12 to exert further torque and therefore pressure on the tines. This further torque or pressure can be released when the bias is released.

[0050] Where reference has been made to integers having known equivalents thereof, those equivalents are herein incorporated as if individually set forth. Although the invention has been described inconnection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is appreciated that further modifications may be made to the invention as described herein without departing from the spirit and scope of the invention.

Claims

CLAIMS1. An implement suitable for use as a harrow, the implement including:a. a bar adapted to support a plurality of spaced apart tines along the length of the bar, andb. a mounting for securing the bar directly or indirectly onto a towing vehicle, said mounting incorporating a linkage assembly adapted to permit up-and-down movement of the bar; the linkage assembly connected at one end to a harrow bracket and at its other end to a drawbar bracket, each bracket configured and adapted to permit a limited arc of rotation independently of the other bracket, the plane of rotation of each bracket being substantially perpendicular to the length of the bar supporting the tines.

2. The implement as claimed in claim 1, wherein the linkage assembly includes a linkage bar that extends between the harrow bracket and the drawbar bracket.

3. The implement as claimed in claim 1 or claim 2, wherein the linkage assembly includes a linkage bar that extends between the harrow bracket and the drawbar bracket and a wire cable that extends between the harrow bracket and the drawbar bracket.

4. The implement as claimed in any one of claims 1 to 3, wherein the linkage assembly further includes a biasing means connected to the harrow bracket, the biasing means biasing the harrow bracket towards the drawbar bracket, when in use.

5. The implement as claimed in claim 4, wherein the biasing means is connected at one end to the linkage bar at a point intermediate the harrow bracket and the drawbar bracket and at the other end to the harrow bracket.

6. The implement as claimed in any one of claims 1 to 5, wherein the linkage assembly is configured to allow the harrow bracket to independently rotate up to about 110 degrees relative to the drawbar bracket.

7. The implement as claimed in any one of claims 2 to 5, wherein the linkage bar is an I-bar.

8. The implement as claimed in any one of claims 2 to 7, wherein the harrow bracket and the drawbar bracket each comprise a pair of parallel flanges, arranged one on each side of the linkage bar of the linkage assembly, each of the flanges being pivotally connected to the linkage bar and wherein the pivotal movement is in a plane parallel to the longitudinal axis of the linkage bar.

9. The implement as claimed in any one of claims 1 to 8, further including a biasing means proximate the drawbar bracket that may be optionally actuated to increase the downwardtorque on the linkage assembly to increase the downward pressure on the tines, when in use.

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