WO2023183973A1

WO2023183973A1 - A folding towable harrow

Info

Publication number: WO2023183973A1
Application number: PCT/AU2023/050232
Authority: WO
Inventors: Shane Peter KELLY; Matthew KEEN
Original assignee: Haidnay Innovation Company Pty Ltd
Priority date: 2022-03-29
Filing date: 2023-03-29
Publication date: 2023-10-05

Abstract

A towable harrow is disclosed. The harrow includes: a main frame having a plurality of ground-engaging wheels; a left side frame and a right side frame, each side frame connected to the main wheeled frame so as to allow folding of the side frames inwardly; a tail frame connected to the main wheeled frame so as to allow folding of the tail frame inwardly about a tail pivot axis; at least one harrow chain supported by one or more of the frames; a tail frame actuator mechanism, the tail frame actuator mechanism including: a linear actuator, the linear actuator having a rod and a cylinder; a main frame connector, the main frame connector connecting the cylinder to the main frame at a first actuating pivot, the first actuating pivot spaced apart from the tail pivot axis; a tail frame connector, the tail frame connector connecting the cylinder to the tail frame at a second actuating pivot, the second actuating pivot spaced apart from the tail pivot axis; wherein extension of the rod actuates folding of the tail frame inwardly to a folded configuration and wherein retraction of the rod actuates folding of the tail frame outwardly to a deployed configuration.

Description

A FOLDING TOWABLE HARROW

TECHNICAL FIELD

[0001] The present disclosure relates to agricultural equipment. In a particular form, the present disclosure relates to towable harrows.

BACKGROUND

[0002] Harrows used in agriculture, for instance chain harrows having disc chains or prickle chains are typically towed behind a vehicle such as a tractor. Such harrows are used for a variety of purposes, such as breaking up the soil, breaking up sods, furrowing the soil, depositing material back in to the ground, levelling the ground and/or breaking up or uprooting weeds or stubble.

[0003] In order to improve efficiency, harrows have become larger in width and hence size. Larger harrows are typically more difficult to transport when not in use, especially on public roads.

[0004] There is thus a need to provide a wide harrow capably that is more easily transported when not in use.

SUMMARY

[0005] According to a first aspect of the disclosure, there is provided a towable harrow including: a main frame having a plurality of ground-engaging wheels; a left side frame and a right side frame, each side frame pivotally connected to the main wheeled frame so as to allow folding of the side frames inwardly; a tail frame pivotally connected to the main wheeled frame so as to allow folding of the tail frame inwardly about a tail pivot axis; a left rear harrow chain extending between the left side frame and the tail frame; a right rear harrow chain extending between the right side frame and the tail frame; a tail frame actuator mechanism, the tail frame actuator mechanism including: a linear actuator, the linear actuator having a rod and a cylinder; a main frame connector, the main frame connector connecting the cylinder to the main frame at a first actuating pivot, the first actuating pivot spaced apart from the tail pivot axis; a tail frame connector, the tail frame connector connecting the cylinder to the tail frame at a second actuating pivot, the second actuating pivot spaced apart from the tail pivot axis; wherein extension of the rod actuates folding of the tail frame inwardly to a folded configuration and wherein retraction of the rod actuates folding of the tail frame outwardly to a deployed configuration.

[0006] In one form, the main frame connector includes: a main frame connector frame end and a main frame connector cylinder end, the main frame connector frame end pivotally connected to the main frame at the first actuating pivot; and the tail frame connector includes: a tail frame connector frame end and a tail frame connector cylinder end, the tail frame connector tail frame end pivotally connected to the tail frame at the second actuating pivot.

[0007] In one form, the float mechanism facilitating rotational float of the tail frame with respect to the main frame without movement of the rod with respect to the cylinder while the tail frame is in the deployed configuration.

[0008] In one form, the float mechanism includes a floating mode and a non-floating mode, wherein the non-floating mode is operable to prevent shock loads during folding of the tail frame.

[0009] In one form, the float mechanism includes a slot and a slot pivot within the tail frame actuator mechanism, the slot and the slot pivot forming one or other of the first or second actuating pivots, and wherein the slot pivot is slidably moveable within the slot from a first slot end to a second slot end.

[0010] In one form, the slot is defined by a pair of spaced apart parallel walls, at least one of the walls orientated such that during folding, while on a substantially horizontal surface, the second actuating pivot remains in the first slot end.

[0011] In one form, the at least one slot wall is orientated at between 85 and 95 degrees with respect to a line-of-force that arises within the tail frame connector during folding when the force within the tail frame connector transitions from tension to compression while the main frame is on a horizontal surface.

[0012] In one form, the float mechanism includes float-lock assembly, the float-lock assembly arranged and constructed to provide the floating and non-floating modes.

[0013] In one form, the float-lock assembly includes a tail frame float-lock element on the tail frame and a tail frame connector float-lock element on the tail frame connector. [0014] In one form, the tail frame float-lock element includes a stopper surface and, wherein the tail frame connector float-lock element includes a follower surface, the stopper surface and the follower surface mutually arranged and constructed to provide the floating and non-floating modes.

[0015] In one form, the stopper surface is on the tail frame and the follower surface is on the tail frame connector.

[0016] In one form, the follower surface is disengaged from the stopper surface in the deployed condition and is engaged with the stopper surface during at least a defined tail frame folding arc, whereby engagement of the follower surface with the stopper surface prevents sliding movement of the second actuating pivot with respect to the tail frame.

[0017] In one form, the slot and tail frame actuator mechanism are dimensioned such that the rotational float is at least plus or minus 5 degrees, whereby within the float rotation, the tail frame is pivotally moveable with respect to the main frame without substantial resistance from the tail frame actuator mechanism.

[0018] In one form, the cylinder ends of the main frame and tail frame connectors pivot about a cylinder pivot.

[0019] In one form, the tail frame actuator mechanism includes a pair of main frame connectors, a pair of tail frame connectors and a pair of linear actuators.

[0020] In one form, the linear actuator is a hydraulic actuator.

[0021] In one form, the left and right harrow chains include discs.

[0022] According to a second aspect of the disclosure, there is provided a folding towable harrow including: a main frame having a plurality of ground-engaging wheels; a left side frame and a right side frame, each side frame pivotally connected to the main frame so as to allow folding of the side frames inwardly; a tail frame pivotally connected to the main wheeled frame so as to allow folding of the tail frame inwardly about a tail pivot axis; at least one harrow chain supported by one or more of the main frame, the left side frame and the tail frame; a tail frame actuator mechanism, the tail frame actuator mechanism including: a linear actuator, the linear actuator having a rod and a cylinder; a main frame connector, the main frame connector connecting the cylinder to the main frame at a first actuating pivot, the first actuating pivot spaced apart from the tail pivot axis; a tail frame connector, the tail frame connector connecting the cylinder to the tail frame at a second actuating pivot, the second actuating pivot spaced apart from the tail pivot axis; wherein extension of the rod actuates folding of the tail frame inwardly to a folded configuration and wherein retraction of the rod actuates folding of the tail frame outwardly to a deployed configuration.

BRIEF DESCRIPTION OF DRAWINGS

[0023] Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:

[0024] Figure 1 is a plan view of a towable harrow according to the disclosure in an unfolded, operable, condition;

[0025] Figure 2 is a perspective view of the harrow of Figure 1;

[0026] Figures 3, 4 and 5 are perspective views of the harrow of Figure 1 in progressively more folded conditions;

[0027] Figures 6 is a perspective view of the harrow of Figure 1 in a completely folded condition;

[0028] Figures 7 is a side view of the harrow of Figures 1 and 6 in a completely folded condition;

[0029] Figure 8 is a similar view to that of Figure 7, but shows a portion of the harrow of Figures 7 in a close up view;

[0030] Figures 9, 10, 11, 12 and 13 shows a portion of the harrow and the linear actuator component of the harrow of Figures 1 and 2 progressively folding from an unfolded to a partially folded position up to 45 degrees to a partially folded position up to 90 degrees to a partially folded position up to 135 to a fully folded position; [0031] Figures 14 and 15 shows a portion of the harrow and the linear actuator component illustrating a first float mechanism;

[0032] Figure 16 shows a tail frame portion of the harrow of Figures 1 tol3;

[0033] Figures 17A and 17B show a portion of the harrow without a float mechanism;

[0034] Figures 18, 19 and 20 show a portion of the harrow and the linear actuator component of a further alternative embodiment which also provides a float mechanism;

[0035] Figures 21A and 21B show a portion of the harrow and the linear actuator component of a further alternative embodiment which also provides a float mechanism;

[0036] Figures 22A to 22D show progressive actuation of the linear actuator component of Figures 21 A and 21B;

[0037] Figures 23 and 24 show schematically alternative arrangements a tail frame actuator mechanism of the towable harrow of the invention; and

[0038] Figures 25A to 25D show an alternative embodiment including a float-lock assembly in different positions as the tail frame folds from the deployed condition of Figure 25A to a folded position of Figure 25D.

DESCRIPTION OF EMBODIMENTS

[0039] Referring to Figures 1 and 2, there is shown a towable harrow according to the disclosure in a plan view and in an unfolded, operable, condition. The towable harrow 10 includes: a main frame 100 having a plurality of ground-engaging wheels 110; a left side frame 200 and a right side frame 300, each side frame pivotally connected to the main wheeled frame so as to allow folding of the side frames 200 inwardly.

[0040] The left side frame 200 and the right side frame 300 are offset from each other to provide compact folding. The left and right side frames include inner 210, 310 and outer side frames 260, 360. The left side frame 200 includes a ground engaging wheel 290 and the right side frame 300 includes a ground engaging wheel 390. [0041] The folding towable harrow 10 also includes a tail frame 400 pivotally connected to the main wheeled frame so as to allow folding of the tail frame 400 inwardly about a tail pivot axis 415. The axis 415 is illustrated in Figures 2, 3 and 4. The tail frame 400 has ground engaging wheels 480, as is shown in Figures 2 and 4 for instance. In Figure 2, the ground engaging wheels 480 are positioned to engage the ground, whereas in Figure 4, the ground engaging wheels 480 are elevated with the tail frame 400 partially folded.

[0042] In the embodiment illustrated, the main frame 100 has four ground-engaging wheels 110 as indicated on Figure 2, however in other embodiments, more or less wheels may be used.

[0043] The main frame 100 and the side frames 200 are constructed from steel, employing hollow sections. However, any suitable materials may be used.

[0044] Harrow chains are suspended from the frames, as is illustrated in Figures 1 and 2 for instance. For example, a left rear harrow chain 280 extends between the left side frame and the tail frame 400 and a right rear harrow chain 380 extends between the right side frame 300 and the tail frame 400. Further harrow chains, being left front harrow chain 280’ and right front harrow chain 380’, are also provided. Each of the harrow chains 280, 380, 280’ and 380’ includes a plurality of discs and a chain with a plurality of links. The discs generally face forward. This facilitates a greater ability to engage the soil and to furrow the soil. The harrow chains are generally of the type illustrated and described in the US patent US7607489B2, the contents of which is hereby incorporated by reference.

[0045] A tail frame actuator mechanism 500 is provided, as is indicated on Figures 1 and 2. A particular embodiment of the tail frame actuator mechanism 500 is shown in close-up illustrations of Figures 9 to 13. It can be seen in these Figures that the tail frame actuator mechanism 500 includes: a linear actuator 600, the linear actuator having a rod 660 and a cylinder 610 (the rod 660 visible in Figures 10 to 12 in which it is extended to various degrees). A main frame connector 510 connects the cylinder 610 to the main frame 100 at a first actuating pivot 511. The first actuating pivot 511 is spaced apart from the tail pivot axis. A tail frame connector 560 also connects the cylinder 610 to the tail frame 400 at a second actuating pivot 561. The second actuating pivot 561 is also spaced apart from the tail pivot axis. Extension of the rod 660 actuates folding of the tail frame 400 inwardly and retraction of the rod 660 actuates folding of the tail frame 400 outwardly.

[0046] The tail frame actuator mechanism 500 is able to handle high loads and also provides the long travel necessary to achieve the folding from the deployed condition shown in Figure 1 to the ready -for- towing on road condition shown in Figures 6, 7 and 8. The geometry of the tail frame actuator mechanism 500 as described above and as is shown in the drawings allows the use of a relatively short stroke cylinder. Such a cylinder 610 mounted as described above is capable of producing the strongest hydraulic action when lifting the tail frame from the ground level position shown in Figures 1, 2 and 9 to the transport position shown in Figures 6, 7 and 8. One reason that the mounting of the linear actuator as described above results in the more powerful extension stroke is that there is a maximum area of piston surface area exposed to hydraulic pressure available for the initial lifting of the tail frame from the ground level position shown in Figure 1, 2 and 9 to the partially lifted position shown in Figure 10. More broadly, linear hydraulic actuators produce more force during extension than during retraction and the tail frame actuator mechanism 500 of the disclosure takes advantage of this characteristic.

[0047] The linear actuator 600 is a double acting hydraulic cylinder. In other embodiments, alternative linear actuators may be used, for instance electric linear actuators.

[0048] The tail frame actuator mechanism 500 and in particular, the rod of its hydraulic cylinder, is protected during harrowing by virtue of its positioning and configuration as illustrated in Figures 2 and 8. As can be seen in Figure 9, the rod 660 is fully retracted during harrowing and therefore it is less susceptible to scratching or other damage that may otherwise arise from clods of earth, stones and dust. Similarly, the bearing surfaces within the cylinder 610 are protected.

[0049] Various mounting options for the hydraulic cylinder 600 are possible, however trunnion mounting offer advantages wherein the trunnions form part of the hydraulic cylinder 600 and provide attachment points for the cylinder end 514 of the main frame connector 510 and for the cylinder end 564 of the tail frame connector 562 as is shown in Figure 9 for instance.

[0050] Figure 9 also shows cylinder end 514 of the main frame connector 510, cylinder end 564 of the tail frame connector 562 and the cylinder 610 meeting a common pivot point 650 on the cylinder.

[0051] Folding of the harrow 10 is shown progressively in Figures 2 to 6 and in close-up Figures 10 to 13.

[0052] The first folding step is shown in moving from the configuration shown in Figure 2 to the configuration shown in Figure 3. Hydraulic actuation of cylinders 220 and 320 causes folding. These cylinders drive their pistons respectively inwards thereby moving the side frames 200 and 300 upwardly and inwardly to the positions shown in Figure 3. In the position shown in Figure 3, a greater proportion of the weight of the chains 280 and 380 is supported by the now elevated ends, 295 and 395. This is also shown in Figure 5. This can reduce the load on the linear actuator 600 of the tail frame actuator mechanism 500 during the next folding stage described below. In some embodiments, there can be a delay in the tail frame actuation until some load has been taken by raising the side frames at least to some extent.

[0053] The next stage of the folding sequence is shown in the transition from Figure 3 to Figure 4. In these Figures, the tail frame pivot axis 415 about which the tail frame 400 pivots is shown.

[0054] The tail frame 400 is lifted by forces produced in the tail frame actuator mechanism 500 described above. As the rods 660 of the linear actuators 600 are pushed outwards from their cylinders 610, the tail frame 400 is folded upwardly and inwardly to the position shown in Figures 3 and 4. From the position shown in Figure 3, the folding continues so that the tail frame 400 finishes in the position shown in Figure 5.

[0055] The final stage of folding is shown in the progression from Figures 5 to 6. This final folding stage is achieved by actuation of the cylinders to 270 and 370 (those cylinders are identified in Figures 2 and 6 in their extended and retracted conditions respectively). Once in this folded condition, the harrow can be towed on a roadway or in other areas having restricted widths and/or lengths.

[0056] As can be seen in the Figures described above, the tail frame actuator mechanism includes a pair of main frame connectors 510, a pair of tail frame connectors 560 and a pair of linear actuators 600, each actuator being substantially the same or being identical and interchangeable. In other embodiments, a different number of linear actuators 600 may be used. For instance, in some embodiments, a single linear actuator 600 may be employed with consequential inclusion of other mounting arrangements.

[0057] Figures 10 to 13 show in further detail the tail frame actuator mechanism 500 described above progressively folding the tail frame inwardly to a folded configuration by extension of the rod 660 of the linear actuator 600. Figures 10 to 13 also show a float mechanism which allows the tail frame 400 to follow the terrain independently of the main frame 100 as is explained as follows.

[0058] The float mechanism facilitates movement of the tail frame with respect to the main frame over the range of positions shown in Figures 14 and 15. The position shown in Figure 14 may occur as the main frame wheels 110 travel into a depression while the tail wheels 480 remain relatively elevated.

Conversely, the position shown in Figure 15 may occur as the main frame wheels 110 travel over a raised surface or hump while the tail wheels 480 remain relatively lower. [0059] Referring to Figures 14 and 15 again, it can be seen that the slot and tail frame actuator mechanism are dimensioned such that the rotational float is at least plus or minus 5 degrees. This allows the tail frame to be pivotally moveable with respect to the main frame without substantial resistance from the tail frame actuator mechanism when in the deployed condition.

[0060] The float mechanism facilitates rotational float of the tail frame with respect to the main frame without movement of the rod with respect to the cylinder while the tail frame is in the deployed configuration.

[0061] The float mechanism includes a floating mode and a non-floating mode, wherein the non-floating mode is operable to prevent shock loads during folding of the tail frame.

[0062] Figure 16 shows a tail frame portion of the harrow of Figures 1 to 13 incorporating part of the float mechanism. The float mechanism includes a slot 420 and a slot pivot within the tail frame actuator mechanism, the slot and the slot pivot forming one or other of the first or second actuating pivots 511, 561.

[0063] Referring to Figure 16, it can be seen that the slot 420 is defined by a pair of spaced apart parallel walls 425. The walls 425 are orientated such that during folding, while on a substantially horizontal surface, the second actuating pivot remains in the first slot end 421.

[0064] Referring now to Figures 17A and 17B, an alternative embodiment is shown without the float mechanism of Figure 9 to 15. With this embodiment, higher forces are transmitted through the components of the towable harrow. The hydraulic circuits and porting may, to some extent ameliorate this in some embodiments.

[0065] Returning float mechanisms, two different examples of float mechanism can be seen in Figures 9 to 16 on the one hand and in Figures 18 to 20 on the other hand. In both cases, the slot pivot is slidably moveable within the slot from a first slot end 421 to a second slot end 422, as is clearly shown in Figures 14 and 15.

[0066] When on level ground, the pivot will sit approximately halfway between the slot ends 421, 422, as is shown in Figures 9 and 18. [0067] The slot and tail frame actuator mechanism are dimensioned such that a float of at least plus or minus 5 degrees is achieved, whereby within the float, the tail frame is pivotally moveable with respect to the main frame without resistance from the tail frame actuator mechanism. In some embodiments, such as those illustrated in Figures 14 to 15 and in Figures 18 to 20, plus or minus 10 degrees is achieved.

[0068] With the embodiment shown in Figure 9 to 15 and in Figure 16, at least one of the slot walls 425 is orientated at between 85 and 95 degrees with respect to a line-of-force within the tail frame connector when the force within the tail frame connector transitions from tension to compression while the harrow is in the process of folding on a horizontal surface. Specifically, it is the slot wall 425 nearest the tail frame connector 560 that is orientated at between 85 and 95 degrees with respect to a line-of-force within the tail frame connector when the force within the tail frame connector transitions from tension to compression while the harrow is in the process of folding on a horizontal surface.

[0069] Referring to Figure 25A, an embodiment of the disclosure is shown where the float mechanism includes float-lock assembly. The float-lock assembly is arranged and constructed to provide the floating and non-floating modes described above. The float-lock assembly includes a tail frame float-lock element 750 on the tail frame and a tail frame connector float-lock element 740 on the tail frame connector.

[0070] The tail frame float-lock element includes a stopper surface 741 and the tail frame connector floatlock element includes a follower surface 751. The stopper surface and the follower surface are mutually arranged and constructed to provide the floating and non-floating modes described above. The stopper surface is on the tail frame and the follower surface is on the tail frame connector.

[0071] The follower surface is disengaged from the stopper surface in the deployed condition as can be seen in Figure 25A and is engaged with the stopper surface during at least a defined tail frame folding arc, as shown in Figures 25C and 25D. In those Figures, it can be seen that engagement of the follower surface with the stopper surface prevents sliding movement of the second actuating pivot with respect to the tail frame. This prevents shock loads which otherwise could damage the structure and potentially cause safety risks.

[0072] Figure 25B shown a point during upwards folding of the tail frame 400 during which the floatlock element transitions from its floating and non-floating modes. [0073] Referring now to Figures 21A and 21B, a portion of the harrow and the linear actuator component of a further alternative embodiment which also provides a float mechanism is shown. This alternative uses a further pivot and link member 490 and a blocking member 495 instead of a slot to provide float.

[0074] Figures 22A to 22D show progressive actuation of the linear actuator component of Figures 21 A and 21B from a partially folded condition in Figure 22A to a fully folded condition in Figure 22D.

[0075] Aside from the many float mechanism mentioned so far, the tail frame connector and/or main frame connector could arms could include a slot or a spring to provide the rotational float. The float could be on the front of the main (centre) frame, instead of on the rear, so that the trunnion arms and connection does not need to accommodate the float.

[0076] Lastly, referring to Figures 23 and 24, alternative arrangements for the tail frame actuator mechanism 500 are shown schematically.

[0077] In the arrangement of Figure 23, in contrast with the arrangement of Figure 9 where cylinder end 514 of the main frame connector 510, cylinder end 564 of the tail frame connector 562 and the cylinder 610 all meet at a common pivot point 650 on the cylinder, a pivot 590 about which the only the cylinder end 514 of the main frame connector 510, cylinder end 564 of the tail frame connector 562 is provided. A separate cylinder pivot 650 is provided on the cylinder 610. It is at this cylinder pivot 650 where the cylinder 610 connects to just the main frame connector 510.

[0078] In the arrangement of Figure 24, the cylinder rod 660 has a rod end pivot 680 that is separate from a tail pivot 410.

[0079] As can be seen from Figures 23 and 24, various alternative arrangements can be employed to achieve the benefits of the disclosure. It will be appreciated that numerous adjustments are possible, each of which will provide advantages and disadvantages for particular embodiments of the inventions.

[0080] One method of operating a towable harrow as described above includes the sequential steps of:

(1) folding the side frames inwardly; and

(2) extending the rod of the actuator from a retracted condition in which the rod is protected to an extended position, the extension of the rod folding the tail frame inwardly, whereby the step of folding the side frames inwardly lifts the left and right harrow chains, before extending the rod of the actuator, thereby reducing the load on the linear actuator that would otherwise arise.

[0081] Another method of operating a towable harrow as described above includes the sequential steps of:

(1) folding the side frames and the tail frame simultaneously.

[0082] The front chains are lifted off the ground as part of the folding sequence.

[0083] The folding towable harrows disclosed here provide significant efficiency advantages to farmers and machinery operators on farm while at the same time providing sufficiently narrow and short harrows in their folded states for legal on-road use. This is important as in many countries and localities there are restrictions on the size of vehicles and their trailers on public roads - for both practical and safety reasons. These restrictions typically include width and length restrictions. The folding sides and tails of the harrows disclosed herein allow for wide and long harrows to be deployed on farm while at the same time allowing a compact road-going trailer.

[0084] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0085] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0086] In some cases, a single embodiment may, for succinctness and/or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c. [0087] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.

Claims

1. A folding towable harrow including: a main frame having a plurality of ground-engaging wheels; a left side frame and a right side frame, each side frame pivotally connected to the main frame so as to allow folding of the side frames inwardly; a tail frame pivotally connected to the main wheeled frame so as to allow folding of the tail frame inwardly about a tail pivot axis; a left rear harrow chain extending between the left side frame and the tail frame; a right rear harrow chain extending between the right side frame and the tail frame; a tail frame actuator mechanism, the tail frame actuator mechanism including: a linear actuator, the linear actuator having a rod and a cylinder; a main frame connector, the main frame connector connecting the cylinder to the main frame at a first actuating pivot, the first actuating pivot spaced apart from the tail pivot axis; a tail frame connector, the tail frame connector connecting the cylinder to the tail frame at a second actuating pivot, the second actuating pivot spaced apart from the tail pivot axis; wherein extension of the rod actuates folding of the tail frame inwardly to a folded configuration and wherein retraction of the rod actuates folding of the tail frame outwardly to a deployed configuration.

2. The folding towable harrow as claimed in claim 1, wherein the main frame connector includes: a main frame connector frame end and a main frame connector cylinder end, the main frame connector frame end pivotally connected to the main frame at the first actuating pivot; and wherein the tail frame connector includes: a tail frame connector frame end and an tail frame connector cylinder end, the tail frame connector tail frame end pivotally connected to the tail frame at the second actuating pivot.

3. The folding towable harrow as claimed in claim 1 including a float mechanism, the float mechanism facilitating rotational float of the tail frame with respect to the main frame without movement of the rod with respect to the cylinder while the tail frame is in the deployed configuration.

4. The folding towable harrow as claimed in claim 3 wherein the float mechanism includes a floating mode and a non-floating mode, wherein the non-floating mode is operable to prevent shock loads during folding of the tail frame. The folding towable harrow as claimed in claim 4 wherein the float mechanism includes a slot and a slot pivot within the tail frame actuator mechanism, the slot and the slot pivot forming one or other of the first or second actuating pivots, and wherein the slot pivot is slidably moveable within the slot from a first slot end to a second slot end. The folding towable harrow as claimed in claim 5, wherein the slot is defined by a pair of spaced apart parallel walls, at least one of the walls orientated such that during folding, while on a substantially horizontal surface, the second actuating pivot remains in the first slot end. The folding towable harrow as claimed in claim 6, wherein the at least one slot wall is orientated at between 85 and 95 degrees with respect to a line-of-force that arises within the tail frame connector during folding when the force within the tail frame connector transitions from tension to compression while the main frame is on a horizontal surface. The folding towable harrow as claimed in claim 5 wherein the float mechanism includes floatlock assembly, the float-lock assembly arranged and constructed to provide the floating and nonfloating modes. The folding towable harrow as claimed in claim 8 wherein the float-lock assembly includes a tail frame float-lock element on the tail frame and a tail frame connector float-lock element on the tail frame connector. The folding towable harrow as claimed in claim 9 wherein the tail frame float-lock element includes a stopper surface and, wherein the tail frame connector float-lock element includes a follower surface, the stopper surface and the follower surface mutually arranged and constructed to provide the floating and non-floating modes. The folding towable harrow as claimed in claim 10 wherein the stopper surface is on the tail frame and the follower surface is on the tail frame connector. The folding towable harrow as claimed in claim 11 wherein the follower surface is disengaged from the stopper surface in the deployed condition and is engaged with the stopper surface during at least a defined tail frame folding arc, whereby engagement of the follower surface with the stopper surface prevents sliding movement of the second actuating pivot with respect to the tail frame. The folding towable harrow as claimed in claim 5, wherein the slot and tail frame actuator mechanism are dimensioned such that the rotational float is at least plus or minus 5 degrees, whereby within the float rotation, the tail frame is pivotally moveable with respect to the main frame without substantial resistance from the tail frame actuator mechanism. The folding towable harrow as claimed in claim 2, wherein the cylinder ends of the main frame and tail frame connectors pivot about a cylinder pivot. The folding towable harrow as claimed in claim 2, wherein the tail frame actuator mechanism includes a pair of main frame connectors, a pair of tail frame connectors and a pair of linear actuators. The folding towable harrow as claimed in claim 1, wherein the linear actuator is a hydraulic actuator. The folding towable harrow as claimed in claim 1, wherein the left and right harrow chains include discs. A folding towable harrow including: a main frame having a plurality of ground-engaging wheels; a left side frame and a right side frame, each side frame pivotally connected to the main frame so as to allow folding of the side frames inwardly; a tail frame pivotally connected to the main wheeled frame so as to allow folding of the tail frame inwardly about a tail pivot axis; at least one harrow chain supported by one or more of the main frame, the left side frame and the tail frame; a tail frame actuator mechanism, the tail frame actuator mechanism including: a linear actuator, the linear actuator having a rod and a cylinder; a main frame connector, the main frame connector connecting the cylinder to the main frame at a first actuating pivot, the first actuating pivot spaced apart from the tail pivot axis; a tail frame connector, the tail frame connector connecting the cylinder to the tail frame at a second actuating pivot, the second actuating pivot spaced apart from the tail pivot axis; wherein extension of the rod actuates folding of the tail frame inwardly to a folded configuration and wherein retraction of the rod actuates folding of the tail frame outwardly to a deployed configuration.