WO2013030534A1

WO2013030534A1 - Cultivator

Info

Publication number: WO2013030534A1
Application number: PCT/GB2012/052025
Authority: WO
Inventors: Arthur Philip Harvey BROCK
Original assignee: Brock Arthur Philip Harvey
Priority date: 2011-08-26
Filing date: 2012-08-20
Publication date: 2013-03-07
Also published as: GB201604049D0; GB2533507A; EP2747539A1; GB2493964B; GB201114746D0; GB2493964A; GB2533507B

Abstract

A cultivator (1) comprises a drawbar (2), a main frame (3), at least one sub frame (14a) to (8c) and at least two wheels (19,22) wherein: the cultivator (1) has a longitudinal direction and a width direction with the drawbar (2) attached at a front end of the main frame (3) so that the cultivator can be towed in the longitudinal direction; the main frame (3) comprises at least two parallel longitudinal frame side members (5a, 6a) spaced from each other in the width direction, each side member having a plurality of first engaging members (7); wheels (19, 22) are mounted on a sub frames (17a) having a plurality of second engaging members (53) arranged to engage with the first engaging members (7) at a plurality of different locations on the main frame (3), to permit the wheels (19, 22) to be mounted to the main frame (3) at any one of a plurality of different locations in the longitudinal direction.

Description

Cultivator

The present invention relates to a cultivator to be towed behind a tractor. An increase in the draught power available from modern tractors has resulted in the development of large cultivators, carrying multiple types of tools, enabling the cultivator to perform a number of operations on a single pass. This reduces the number of passes over a field, for example between harvesting and sowing, saving time and reducing compaction of the field.

The significant draught power that can be applied to a cultivator, particularly when working compacted or heavy soil, requires large cultivators to have a strong, substantially rigid, frame structure to convey this power to the tools working the soil. Typically, the frame comprises a central spine extending from the drawbar to a set of transport wheels, with tools being mounted on spars extending transversely from the spine, or mounted on sub frames supported by spars mounted transversely from the spine, with the spars or sub frames sometimes being foldable to a vertical position, to permit transport of the cultivator on roads or through gateways. The considerable forces exerted upon the frame and the requirement for the frame to be rigid, so that the spars extending from the central spine do not flex or bend, requires the spine to be very strong and this can account for the majority of the weight of the cultivator. Excessive weight is undesirable because, where the transport wheels or guide wheels are used to control the working depth, this will itself cause compaction of the soil. It is thus preferable that the cultivator is relatively light.

Large cultivators are also expensive relative to a single packer, harrow, set of tines or similar and they also require a large storage space. In addition the range of cultivators a manufacturer or supplier can offer is also often limited, so it is common to configure a standard frame of a cultivator so that it can perform a specific task on a specific soil type. This is normally achieved by bolting appropriate tools on to a frame at desired locations. The cultivator will then only be used for the selected task or similar tasks and even then a particular configuration may not be optimised for all soil types that may be encountered. For example if the soil is particularly compacted or heavy (wet) it may clog. However, the work involved in reconfiguring the cultivator means that this is not normally practical. It may also not be possible to increase the spacing between tools or fit different tools on the cultivator, being restricted by the frame structure available for bolting various tools to and the length of frame available between the drawbar and the transport wheels, or behind the transport wheels, where these are located towards the middle of the frame.

It is an object of the present invention to provide an improved cultivator.

According to a first aspect of the present invention, there is provided a cultivator comprising a drawbar, a main frame, at least one sub frame and at least two wheels, wherein: the cultivator has a longitudinal direction and a width direction with the drawbar attached at a front end of the main frame so that the cultivator can be towed in the longitudinal direction; the main frame comprises at least two parallel longitudinal frame members spaced from each other in the width direction, each frame member having a plurality of first engaging members; the wheels are mounted on a sub frame, the sub frame having a plurality of second engaging members arranged to engage with the first engaging members at a plurality of different locations on the main frame, to permit the wheels to be mounted to the main frame at any one of a plurality of different locations in the longitudinal direction.

A cultivator in accordance with the present invention provides a frame that can be configured for a specific job or soil type and is not limited to having the wheels in any specific location on the main frame. For example the wheels can be mounted towards the centre of the frame so that tools can be mounted behind the wheels and work the soil compressed by the wheels. This may permit a packer to be mounted to the rear of the frame. Alternatively, the wheels may be mounted to the rear of the frame with the tools mounted between the frame and the drawbar, or the wheels may be located in any intermediate position, as required. Preferably, the cultivator further comprises a plurality of sub frames at least some of which have a plurality of tools attached thereto, which sub frames each have second engaging members so that they can be mounted to the main frame at any one of the plurality of locations in the longitudinal direction. This feature of the invention enables the first engaging members on the longitudinal frame members to mount either the wheels or tools at a location on the longitudinal frame members. Where the first engaging members are equally spaced, which for example may be at 100 mm spacing, then either the wheel carrying sub frame or a tool carrying sub frame may be placed at any desired location. This may permit a minimal clearance between successive tools in the longitudinal direction to be achieved, where soil conditions permit and thus permit a maximum number of tools to be carried by the cultivator for any particular soil conditions or type of soil.

Preferably, the first engagement members extend over at least half the length of the respective longitudinal frame members.

A cultivator in accordance with the present invention may also enables a plurality of tools mounted on a sub frame to be removed, inserted or moved in the main frame of the cultivator as a single block, simply by moving the appropriate sub frame. Thus, for example, a first sub frame may carry discs angled in a first direction with a second sub frame carrying discs angled in a second direction with subsequent sub frames carrying staggered tines. With such an arrangement, the tools may be closely spaced if the soil type permits but if the soil should be particularly wet for example and additional spacing required between the tools, then the sub frames can be repositioned upon the longitudinal frame members without having to release the tools from the sub frames.

It is particularly advantageous if the sub frames are lowered into the main frame, permitting a loader or other similar farm equipment to lift the sub frames into or out of position. Preferably, a locking mechanism is employed for locking the sub frames in position on the main frame, which locking mechanism may be used without the use of tools. The locking mechanism may comprise hooks mounted on the sub frames which hooks attach under the longitudinal frame members to secure the sub frames in place, with a locking pin provided to ensure the hooks do not unintentionally release.

Preferably, the first engaging members are in the form of a rack and each sub frame is the form of a beam having a plurality of teeth at each end arranged to engage with racks of respective longitudinal frame members. This permits sub frames to be interchangeable and located at different positions on the main frame in different configurations. It permits tools or the wheels to be moved on the main frame simply by unlocking and lifting the appropriate sub frame out of the main frame and repositioning it. Alternatively a sub frame may be substituted with another sub frame carrying a different set of tools.

Preferably, each longitudinal frame member comprises a strip of flat steel plate arranged in a vertical plane so that it may flex in the width direction of the cultivator, the longitudinal frame members being connected towards their front ends to a substantially rigid front cross member attached to the drawbar. This permits a draught force exerted on the drawbar to be transferred via the front cross member to the longitudinal frame members with the longitudinal frame members, having a high tensile strength, transferring the draught force to the sub frames and any tools attached thereto. Because the longitudinal frame members have a significant depth in the vertical direction they resist flexing in the vertical direction and thus maintain the tools at a desired height relative to the drawbar, transport wheels or any guide wheels supporting the frame. They also resist rotation of the sub frames as tools work the soil. Thus the frame may flex in the width direction of the cultivator whilst still maintaining the tools in a desired position and propelling them through the soil. However by permitting the frame to flex in the width direction the frame can be significantly lighter than a frame employing a central rigid spine with a number of spars mounted transversely thereto on which the tools are mounted.

Advantageously, the main frame comprises a central section and two side sections, (or wings), each of the central and side sections comprising two longitudinal frame members with a front cross member and at least one sub frame extending there between, with the longitudinal frame members of the central section being hinged to adjacent longitudinal frame members of respective adjacent side sections to permit the side sections to be folded on the main section.

This arrangement permits tools and wheels mounted on the side sections to be raised for transportation purposes. Preferably the central section is twice the width of the side sections and the side section can be folded through at least 135° to lie above the central section. Folding the side sections flat, or almost flat on top of the central section minimises transportation width, relative to folding the side sections through 90°, where the tools would protrude to the sides in a dangerous manner. In addition, if the wheels or any packer in contact with the ground extend to the edges of the central section then this provides a particularly stable arrangement. Thus, in this mode, a particularly stable and narrow configuration may be provided for transportation purposes. It may also permit the side sections to be folded and the cultivator then used to obtain maximum draught force on any tools, such as sub soilers mounted on the central section, for example when breaking up tramlines or performing headland operations.

Each of the main and side sections of the main frame may have a set of wheels mounted on a respective sub frame, the cultivator further comprising rams connected between the central section wheel carrying sub frame and respective side section wheel carrying sub frames, wherein the rams are arranged to act between the respective wheel carrying sub frames to cause the side section sub frames to be folded or extended, folding or extending the side sections of the main frame to which the wheel carrying sub frames are engaged. In this manner, the wheel carrying sub frames not only act as a platform through which the wheels can be connected to the longitudinal frame members, but also permit the strength of these wheel carrying sub frames to function as cross members on which rams act to fold the side sections of the main frame. Preferably, the total tread width of the wheels is greater than 50% of the width of the frame. With tread width in excess of 50% of the frame width, the wheels themselves may perform a rolling operation, with the pressure exerted by each wheel significantly reduced compared to a typical two wheeled cultivator. If the tread width is greater than 50% of the width of the frame, it also ensures the frame is a particularly stable platform for tools, being less affected by irregularities, such as tramlines, in the soil surface. Preferably, the cultivator comprises a ram acting to raise or lower the wheels relative to the sub frame, permitting the height of the sub frame to be controlled and thus the depth of tools mounted on the cultivator to be controlled.

The cultivator may comprise a packer mounted to the rear of the frame, which packer can be fixed in a lowered position so that when the wheels are raised the packer supports at least a portion of the weight of the cultivator, applying a positive pressure to the packer. Alternatively, the packer can be set to float, where it does not support the weight of the cultivator. Advantageously, the or each wheel carrying sub frame can be released from the main frame, the sub frame raised so that the first and second engaging members disengage and the wheel carrying sub frame can be then be slid along the main frame . Thus, if it is desired to move the wheels in the main frame, the wheels may be raised such that the second engaging members hang from the first engaging members, permitting any locking means to be released, with the wheels then lowered acting to lift the second engaging members out of the first engaging members. The wheel carrying sub frame may then be slid to a new position. This may be assisted if a rigid tool, for example a bar connected to a forklift loader, is engaged with the wheel carrying sub frame, or components attached to the sub frame, to prevent rotation of the sub frame. Thus 'lowering' the wheels will then cause the sub frame to be raised out of the main frame. If this method is used, the forklift may then be manoeuvred to slide the wheels and sub frame forward or backwards within the main frame to a desired position where the sub frame can again engage the main frame and be locked in place. According to a second aspect of the present invention there is provided a cultivator comprising a drawbar, a main frame, at least one sub frame and at least two wheels, wherein: the cultivator has a longitudinal direction and a width direction with the drawbar attached at a front end of the main frame so that the cultivator can be towed in the longitudinal direction; the main frame comprises at least two parallel longitudinal frame side members spaced from each other in the width direction, each side member having a plurality of first engaging members; the wheels are mounted on a sub frame, the sub frame having a plurality of second engaging members arranged to engage with the first engaging members at a plurality of different locations on the main frame, to permit the wheels to be mounted to the main frame at any one of a plurality of different locations in the longitudinal direction. According to this aspect of the invention, the tine located on a transverse beam forward of the beam may be positioned closely behind a preceding tool such as disc. In addition, forward mounted and rear mounted tines may be alternately mounted on the same beam to provide a staggered pattern, whilst minimising the frame structure necessary to make this possible.

Preferably, each tine mounting comprises a mounting plate and a carrier for the tine, wherein the mounting plate is mounted on the transverse beam of the cultivator, the mounting plate having the carrier pivotally connected thereto and located forward of the beam, in which carrier the tine is held, the spring acting between the mounting plate and the carrier to urge the carrier against a stop where the tine is located in a desired working position, the carrier, in use, pivoting against the action of the spring when the tine exerts a sufficient force on the carrier, for example when the tine hits an obstruction.

The spring may be a compression spring located above the position of the beam, transverse to the beam, the spring being held at a forward end by the mounting plate with an aft end of the spring being held in place by a linkage, the linkage being pivotally connected at spaced locations to both the spring and a mounting plate, the mounting further comprising a connecting rod connected at a forward end to the carrier and at an aft end to the linkage, whereby rotation of the carrier causes the connecting rod to rotate the linkage and compress the spring. In the above discussion of a tine mounting, reference has been made to a mounting plate in the singular. However, it will be appreciated that the mounting plate by which the tine mounting is mounted on a transverse beam could comprise a single component or multi components which, for example may be bolted together. Thus, the term 'mounting plate' as used in the context of this specification is to be interpreted to encompass any structure that comprises a surface for abutting against a transverse beam of a cultivator and the term 'mounting plate' is also to encompass structures comprising two or more components which are each arranged to abut the transverse beam. A cultivator in accordance with the above mentioned aspect of the present invention may be particularly advantageously employed in combination with a cultivator in accordance with the first aspects of the invention. The cultivator may comprise a plurality of sub frames each with a plurality of second engaging members by which the sub frames may be mounted to the main frame by the first engaging members at any one of the plurality of locations in the longitudinal direction, wherein at least some of the sub frames are in the form of transverse beams and have tine mountings in accordance with the second aspect of the invention mounted thereon. This arrangement of tine mountings may maximise the number of sub frames and tools that can be carried by a the cultivator main frame.

According to the third aspect of the present invention there is provided a cultivator comprising: a frame to which tools can be attached, a set of wheels; an axle supporting at least one wheel; a trailing arm connecting the axle to the frame; and a ram acting directly or indirectly between the frame and axle to raise and lower the wheels relative to the frame, the cultivator further comprising a scraper located behind the at least one wheel and/or a multipoint linkage for attaching farm implements, the scraper and/or multipoint linkage being supported by a hub on the axle, the cultivator further comprising a linkage

mechanism arranged to retain the scraper and/or multipoint linkage with a desired vertical alignment, irrespective of the position of the wheel relative to the frame.

In accordance with the third aspect of the present invention, there is provided a cultivator wherein a scraper blade and/or multipoint linkage (which for example may be a traditional three point linkage) may be arranged to maintain a set height relative to the bottom of a wheel of the cultivator and be maintained at a set orientation, even though the wheel is mounted to the frame by a trailing arm and the wheel may be raised or lowered relative to the frame. Thus, provided the wheel is in contact with the ground, irrespective of the height of the frame to the ground, the scraper and/or the multipoint linkage will be retained in at a set height relative to the ground. This is advantageous in enabling a scraper to be set very close to the ground, thus removing soil from the wheel as it is raised from the ground and thus depositing that soil in the region from which it was originally displaced. Where a multipoint linkage is employed then, a farm implement, such as a drill, may be mounted on the multipoint linkage, maintained at a set height above the ground and at a set inclination to the ground, with the weight of that implement being carried on the wheel. This arrangement is particularly advantageous where multiple wheels are employed to support the cultivator and the combined tread width of the wheels is greater than 50% of the width of the main frame. In this manner, the weight of any implement mounted on the multipoint linkage may be dispersed across the complete tread width, minimising compaction of the soil by the wheels. This will also ensure any irregularities in the soil surface cause a minimum displacement of the implement. The linkage mechanism may comprise said first lower trailing arm extending from a lower point on the frame to a hub on the axle of the wheel and a first upper trailing arm extending from a higher point on the frame to a pivot point above the hub, the first lower and first upper trailing arms being linked by a first cross member pivotally connected to both the first upper and first lower trailing arms at points between their ends, the geometry of the trailing arms and first cross member being arranged to maintain the pivot point above the hub substantially a constant distance above and substantially vertically in line with the hub, the linkage mechanism further comprising upper and lower extension arms extending rearward respectively of the pivot point above the hub and the hub to a second cross member to which they are pivotally connected at vertically separated points to form a substantially parallel linkage, wherein the scraper and/or multipoint linkage are supported by the second cross member. Preferably, a ram is provided for the linkage mechanism which ram is connected directly or indirectly between the frame and linkage mechanism to control the height of the scraper and/or multipoint linkage relative to the bottom of the wheel, irrespective of the position of the wheel relative to the frame. The linkage mechanism ram is preferably arranged such that when actuated it will lift or lower the scraper and/or multipoint linkage and at its full extent of travel in one direction will determine the scraper and/or multipoint linkage height relative to the bottom of the wheel. In this manner, the ram may be arranged to set an implement on the multipoint linkage, or the scraper, to a desired position simply by the ram being set to the limit of its travel in one direction. Preferably a manual adjuster is also provided to control the height relative to the bottom of the wheel of the scraper and/or multipoint linkage when the linkage mechanism ram is at its limit of travel, for this manual adjustment permits the linkage mechanism to be adjusted when a particular implement, for example a seed drill, is mounted on the multipoint linkage so that the implement is mounted at a desired height.

It may be particularly advantageous to attach a drill to the multipoint linkage when the drill is arranged such that the sowing depth is set relative to the bottom of the wheel. This may permit the cultivator to be configured so that it may both till and drill, whereby a stubble field, for example, may tilled and sowed on a single pass. Having a sowing depth set by the wheels of the cultivator may permit a significant pressure to be applied to the seed coulters whilst maintaining them at a desired depth in the soil. It may also simplify the construction of the drill avoiding the need for individual depth control of the seed coulters of the drill. According to a fourth aspect of the invention there is provided a cultivator comprising a drawbar, a main frame, a plurality of sub frames having tools attached thereto and at least two wheels, wherein: the cultivator has a longitudinal direction and a width direction with the drawbar attached at a front end of the main frame so that the cultivator can be towed in the longitudinal direction; the main frame comprising at least two parallel longitudinal frame side members spaced from each other in the width direction, each side member having a plurality of first engaging members; the sub frames have second engaging members so that they can be mounted to the side frames at any one of a plurality of locations in the longitudinal direction; and each of said side members is formed from a strip of flat steel plate arranged in a vertical plane so that it may flex in the width direction of the cultivator, the side members being connected to a substantially rigid front cross member attached to the drawbar.

A cultivator in accordance with the fourth aspect of the invention is particularly advantageous because a significant reduction in the frame weight may be achieved relative to conventional rigid frames, for example employing a single spine with transverse spars rigidly mounted thereto.

The invention will now be described below, by way of example only, with reference to the accompanying drawings, of which:

Figure 1A is a plan view of a cultivator in accordance with the present invention;

Figure IB is a side elevation of the cultivator of Figure 1A;

Figure 2A is a plan view of the cultivator of Figure 1A, with an alternative tool configuration;

Figure 2B is a side elevation of the cultivator of Figure 2A;

Figure 3 A is a plan view of the cultivator of Figure 1 A, with a further alternative tool configuration;

Figure 3B is a side elevation of the cultivator of Figure 3A;

Figure 4 illustrates a folding mechanism of the cultivator of Figure la, extended;

Figure 5 illustrates the folding mechanism of Figure 4, folded;

Figure 6A is a cross section along the line 6A-6A of Figure 1A;

Figure 6B is a cross- section along the line 6B-6B of Figure 6A;

Figure 7A corresponds to Figure 6A showing the sub frame depicted in Figure 6A being removed;

Figure 7B is a cross section along the line 7B-7B of Figure 7A;

Figure 8 illustrates a parallel linkage mechanism associated with the wheels of the cultivator illustrated in Figures 1A to 3B with the wheels in a lowered position and the multipoint linkage lowered;

Figure 9 corresponds to Figure 8 but showing the multipoint linkage raised; Figure 10 corresponds to Figure 8 with the multipoint linkage lowered and the wheels raised;

Figure 11 illustrates a tine mounting in accordance with an aspect of the present invention, employed on the cultivator of Figure 1 A;

Figure 12 illustrates the tine mounting of Figure 11 with the tine partly retracted; and

Figure 13 illustrates how the mounting of Figure 12 may be modified to carry a rear mounted tine. Referring to Figures 1A and IB, a cultivator, indicated generally as 1 comprises a drawbar 2 and a main frame 3 comprising a central section 3a and side sections 3b and 3c. Each section 3a, 3b, 3c of the main frame 3 comprises respectively a box section steel cross member 4a, 4b, 4c and opposed pairs of frame side members 5a and 6a, 5b and 6b, 5c and 6c. Each side member 5a to 6c is formed from a flat steel plate which, as can be seen from Figures 1A and 6 A has steel blocks 7 welded along its lower edges at regularly spaced intervals, which blocks 7 are bridged by steel strip 8 to form racks 9 extending substantially along the entire lengths on the inside faces of the side members 5a to 6c.

The frame side members 5a and 6a of the central section 3a are joined to respective frame side members 6c and 5b of respective adjacent side sections 3b, 3c by frame hinges 10. The frame 3 is supported at its front end by a pair of depth control wheels 11 which may be set to a predetermined depth. Alternatively, these may be raised and the cultivator

1 supported by towing hitch 13 held by the drawbar of a tractor (not shown). The height of the frame 3, at its front end, can then be controlled by drawbar rams 12 acting between the cross member 4a and the drawbar 2, to raise or lower the frame 3 at its front end relative to towing hitch 13. The height can then be set relative to the tractor.

Although not shown, the towing hitch 13 may be pivotally connected to the drawbar

2 with a parallel linkage attached between the towing hitch 13 and the cross member 4a, to maintain the towing hitch 13 in a horizontal plane. This avoids any twisting action being placed on the tractor drawbar as the cultivator drawbar 2 is raised or lowered. With reference to Figure 1 and considering only the central section 3a of the main frame 3, between side members 5a and 6a there are connected a plurality of sub frames 14a to 18a. Each of the sub frames 14a to 18a may be locked in place in a longitudinal position by the ends of a respective sub frame 14a to 18a engaging with a respective rack 9, as will be described below with reference to Figures 6 A to 7B.

Sub frame 17a is a wheel carrying sub frame having wheels 19, 20, 21 and 22 connected thereto. The wheels 19 to 22 are connected in a manner describe below with reference to Figures 8 to 10 so that they may be raised or lowered with respect to the sub frame 17a. The sub frame 17a is connected to the main frame, thus when the wheels 19 to 22 are in contact with the ground raising or lowering the wheels 19 to 22 will cause the central section 3a of the main frame 3 to be lowered or raised accordingly.

Also attached to the wheel carrying sub frame 17a is a multipoint linkage 27a supported by axles of the wheels 19 to 22. This is described below with reference to Figures 8 to 10.

Sub frame 14a has a plurality of discs 28 bolted to it which are angled in a first direction and sub frame 15a has a plurality of discs 29 bolted to it in a second direction opposed to the first direction, so that lateral forces exerted by the two sets of discs 28 and 29 on the central section 3a of main frame 3 are balanced.

Sub frame 16a has a plurality of tine mountings secured to it with some tines 30 mounted forward of the sub frame 16a and some of the tines 31 mounted aft of the sub frame 16a so that the tines are in a staggered pattern to discourage clogging between the tines. These tines and mountings are described below with reference to Figures 11 to 13.

Sub frame 18a has five sub-soilers 32 mounted to it in a forward facing V-pattern.

In the embodiment illustrated in Figures 1A and IB a packer, illustrated generally as 33a, is mounted to the back of the frame side members 5a and 6a. In side elevation, the packer 33a is the same as packer 33c attached to the main frame side section 3c, which is shown in Figure IB.

With reference to Figure IB each frame side member 5a, 6a, 5b, 6b and 5c, 6c has a packer mounting bracket 34 pivotally mounted thereto by pin 35 engaging in a recess in the top of the respective frame side member5a to 6c, such that the packer mounting bracket 34 may pivot about pin 35 in a clockwise direction, as shown in Figure IB. Alternatively, a second pin 36 may be inserted through the respective packer mounting bracket 34, locking the mounting bracket 34 in the position shown in Figure IB. Each of the packers 33a to 33c, seen in Figure 1A, has two lower arms 37 extending to a lower connection point of a respective mounting bracket 34 and has a ram 38, (two rams 38 in the case of central packer 33a), extending between the packer and a corresponding cross beam 39a to 39c, each cross beam terminating in a pair of pins 35. As will be appreciated from Figure 1A, each of the main frame side sections 3b and

3c has equivalent sub frames, wheel arrangement, discs, tines, sub-soilers and packer as the main frame central section 3a, described above, which function in the same manner as those on the central section 3a of the main frame 3. Referring to Figure IB, the depth of the main frame 3 can be controlled at the front end of the cultivator 1, either by depth control wheels 11 or drawbar rams 12 acting on the drawbar of a tractor. Similarly, the height of the frame and thus the depth of the tools towards the rear of the frame can be controlled by the vertical height of the wheels 19 to 26 relative to the main frame 3. In addition, with pins 36 inserted in the packer mounting bracket 34 such that they are locked in place, a positive weight may be applied to the packers 33a to 33c by respective rams 38. Depending on the application, it may be desirable to raise the wheels 19 to 26 completely such that cultivator 1 is supported at the rear purely by the packers 33a to 33c. Where it is not necessary to tow the cultivator on a metalled surface, it may desirable to remove sub frames 17a to 17c together with wheels 19 to 26 and replace them with other tools within the frame. In an alternative arrangement (not shown) to that of Figures 1A and IB, with the wheels 19 to 26 supporting the weight of the cultivator 1, pins 36 securing the packer mounting brackets in place may be removed and the rams 38 fully extended, such that the packer mounting brackets 36 will rotate clockwise relative to the position in Figure IB and the packers 33a to 33c will be free floating. In this mode, the packer mounting plate upper pins 35 will be secured to the frame 3 by a locking means (not shown). However, when the locking means is released the packers 33a to 33c may, if required, be lifted off the rear of the frame. Because each of the sub frames 14a to 18c can be released from respective frame side members 5a and 6c, it is possible to reconfigure the cultivator 1 simply by moving the sub frames with the respective tools mounted thereon within the main frame 3. For example, in the arrangement depicted in Figures 2A and 2B an eleven leg trailed V- formation sub-soiler has been provided within the main frame 3 by moving sub frames 18a, 18b and 18c of Figures 1A to the positions shown in Figure 2A, with the wheel carryings sub frames 17a to 17c moved aft. In this embodiment, packers 33a to 33c are connected to respective multipoint linkages 27a to 27c connected to the wheel carrying sub frame 17a to 17c. In this arrangement, the lower arms 37 of the packers, illustrated in Figure 1A, have been removed and the packer multipoint linkage arms 40 connected to respective multipoint linkages 27a to 27c, discussed in more detail below with reference to Figures 8 to 10.

As a further example, the cultivator 1 could be configured as illustrated in Figures 3A and 3B, with drills 41a to 41c attached to respective multipoint linkages 27a to 27c, each drill comprising a respective drill frame 42a to 42c, each supporting a plurality of coulters 43 and a harrow 44. The central drill 41a having two hoppers 45 mounted above it for supplying seed or the like to coulters 43 on all the frames 42a to 42c. The hoppers 45 have a gap between to permit the main frame to be folded as described below with reference to Figures 4 and 5. As most clearly shown in Figure 3B, the multipoint linkage 27c, as explained below with reference to Figures 8 to 10, can be maintained at a set height relative to a hub 46 of wheel 26. This therefore permits the multipoint linkage 27c to be set at a desired height for a particular drill 41 and the pitch of drill frame 42 can then be set by manual adjuster 47 so that coulters 43 penetrate the soil to a desired depth, controlled by the wheel 26 riding over the soil surface. In this manner accurate depth control of the coulters 43 may be achieved while applying a significant downward force to ensure they reach the desired depth in the soil.

Referring now to Figures 4 and 5, , there is illustrated the mechanism by which the cultivator 1 of Figure 1 A may be folded, with the side sections 3b and 3c of the main frame 3 folded onto central section 3a. With specific reference to Figure 4 there is illustrated a rear view of the wheel carrying sub frames 17a, 17b and 17c of Figure 1A, with the wheels and associated linkages omitted for clarity. The wheel carrying sub frames 17a, 17b and 17c are each locked to respective pairs of frame side members 5a and 6a, 5b and 6b, 5c and 6c. The central wheel carrying sub frame 17a supports two rams 48 which act, via linkage mechanisms 49, on the wheel carrying side sub frames 17b and 17c. When the rams 48 contract, the sub frames 17b and 17c will first be raised and then folded inwardly being forced to rotate about hinges 10 joining adjacent side member frames 6a and 6b, 5a and 6c to which the sub frames 17a to 17c are attached, until the sub frames and thus the main frame 3 adopts the position shown in Figure 5. As shown in figure 1A, identical rams 48 and linkage mechanisms 49 are also mounted on the front cross members 4a to 4c so that the four rams 48, operated together, fold the main frame 3 of the cultivator 1 both from the front and from the location of the wheel carrying sub frames 17a to 17c. A significant advantage of this arrangement is that the relatively heavy sub frames necessary to mount the wheel to the main frame can also be utilised as the structure to fold the side sections 3b and 3c onto the central section 3a of main frame 3.

When the side sections 3b and 3c are folded onto the main section 3a, not only may the cultivator be more easily transported on the road or through gateways, but this may also be a convenient mechanism to transfer maximum draught power to the side sub-soilers 32 in the central section 3a of the frame, without the need to reconfigure cultivator 1. This may be desirable when breaking up trams lines or other heavy compacted areas. It is possible to work the cultivator in a folded state because when folded the side sections 3a and 3c are flat, or nearly flat, upon the main section 3a, lowering the centre of gravity relative to if the side sections of the main frame 3b and 3c had only been folded through 90°, with the various tools and wheels 23 to 26 still extend beyond the width of the central section 3a.

Referring now to Figures 6 A and 6B, there is illustrated the mechanism by which the sub frames 14a to 18c are mounted to the main frame 3, Figure 6A being a cross section along the line 6A-6A of Figure 1A. Each sub frame 14b is welded at its ends to a steel plate 50 having an extension portion 51 with an eye 52 therein which eye, when the sub frame is mounted on frame side member 6b, is above the level and side member 6b.

Along the bottom edge of steel plate 50 are cut a plurality of teeth 53 which engage with the track 9 formed by the steel block 7 and steel strip 8 welded thereto. Projections from the steel plate 50 have upper pins 55 passing therethrough on which locking members 56 are pivotally retained in place. The locking members 56 are in the form of hooks which, under the action of gravity, swing under the rack 9 and frame side member 6b preventing the sub frame 14b from being lifted from the frame side member 6b. The locking members 56 may themselves be locked in position by further pins 57 which can be manually inserted to lock the locking members 56 in place. Alternatively, the further pins 57 can be removed, the locking members 56 manually swung out from under the rack 9 and the further pins reinserted to prevent the locking members 56 reengaging under the racks 9. Hooks can then be engaged with the two eyes 52 at either end of the sub frame 14b and the sub frame 14b lifted as shown in Figures 7 A and 7B out of the frame 3, complete with any tools attached thereto or, in the case of wheel carrying sub frame 17a to 17c, complete with the wheels.

In the case of the wheel carrying sub frame 17a to 17c, these and the associated wheels 19 to 26 can be removed from, or repositioned in, the frame 3 by the wheels being fully raised such that the frame either rests on tools attached to the frame or on some other temporary supports. Then the appropriate sub frame can be unlocked in the same manner as the sub frame illustrated in Figures 7A to 7B and an appropriate means, such as a forklift with an extension tool attached, connected to a trailing arm or some other structure connected to the appropriate sub frame 17a to 17c to prevent rotation of the sub frame. The wheels may then be lowered raising the sub frame to the same position as the sub frame 14b is shown raised in Figures 17A to 17B, whereby the forklift may then be moved backwards or forwards causing the wheel carrying sub frame 17a, 17b or 17c and the wheels attached thereto to be slid either backwards or forwards within the frame 3, to any desired alternative location, or slid out of the back of the frame. The sub frames are replaced in the frame and locked in the frame in the reverse procedure to that described above.

Referring now to Figure 8, there is shown the wheel carrying sub frame 17c of Figure 1 and components attached thereto including: wheel 25; multipoint linkage indicated generally as 27c; wheel scraper 58; and a linkage mechanism 59 to 72.

The wheel 25 is principally attached to sub frame 17c via a first lower trailing arm 59. This supports a hub 60 extending between wheels 25 and 26 of Figure 1 A parallel to the sub frame 17c. Hub 60 retains an axle 61 passing through the hub and supporting the wheels 25 and 26. A first upper trailing arm 62 locates a pivot point 63 substantially above the hub 60 and cross member 64 causes the two trailing arms 59 and 62 to act substantially as a parallel linkage. Thus, when ram 65 acts between the sub frame 17c and first lower trailing arm 59 to raise or lower the wheel relative to the frame 3, the pivot point 63 remains substantially above the hub and at a substantially constant distance from the hub 60.

A second lower trailing arm 66 is pivotally connected to the hub and is free to pivot about the hub 60 independently of the first lower trailing arm 59. A second upper trailing arm 67 is connected to pivot 63. The second upper and lower trailing arms are connected at their other ends to plate 68 which forms the upper point of multipoint linkage 27c. The second lower trailing arm 66 is connected to the plate 68 by bar 69 on which it may pivot. The ends of the bar 69 form the lower two linkage points of the multipoint linkage 27c. A scraper 58 is also pivotally mounted on bar 69 but is prevented from freely rotating about the bar 69 by manual adjuster 70, which is adjusted to set the spacing between the scraper 58 and the wheel 25. Ram 71, shown fully extended in Figure 8, determines the position of vertical arm 72, which is pivotally connected to the second lower trailing arm 66. A second manual adjuster 73 extends between at the top of the vertical arm 72 to a point towards the rear of the second lower trailing arm 66 and is pivotally connected at both ends.

In the position illustrated in Figure 8, ram 71 is fully extended, whereby the height 'd' of the scraper and the multipoint linkage mechanism above the ground can be set by manual adjuster 73. When it is desired to raise the multipoint linkage 27c, ram 71 contracts, as shown in Figure 9 causing the second lower trailing arm 66 to rotate about the hub 60 raising the bar 69, plate 68 and scraper 58 as shown. The scraper 58, being prevented from rotation about the bar 69 by adjuster 70, travel about the circumference of the wheel keeping the same orientation relative to the adjacent surface of the wheel and thus maintaining the same spacing between the edge of the scraper 58 and the wheel 25. In contrast, plate 68 is free to pivot about bar 69 and because of the relative position of the hub 60 and pivot point 63, the second upper trailing arm 67 ensures that the plate 68 retains the same vertical orientation as the multipoint linkage is raised to the position shown in Figure 9.

Figure 10 illustrates how the wheel 25 may be raised or lowered relative to the frame and the position illustrated in Figure 8. The ram 65 is contracted, as shown in Figure 10, causing the upper 62 and lower 59 trailing arms to be raised, thus lowering the sub frame 17c and main frame 3. The hub 60 and pivot point 63 remain in the same position relative to each other and the ground. Because the second upper and lower trailing arms 67 and 66 depend from the hub 60 and pivot 63, the height 'd' of the scraper from the ground and the height and vertical orientation of the multipoint linkage 27c is maintained as the wheels are raised.

Referring now to Figure 11, there is illustrated a cross section along the line 11-11 of Figure 1A, showing in detail the tine mounting 74 of Figures 1A and IB. This mounting permits a tine 30 to be mounted forward of sub frame 16b so that it can be mounted closely behind discs 29, of the Figure 1A and IB embodiment. It also permits a second set of tines 31 to be mounted to the same sub frame 16b so that adjacent tines 30, 3 lean be arranged forward and aft of the sub frame 16b, in a staggered pattern.

With reference to Figure 11, the tine mounting comprises a mounting plate comprising a first portion 75a and second portion 75b secured to sub frame 16b by bolt 76.

Tine 30 passes through a carrier 77 pivotally connected about bolt 78. The carrier 77 also being pivotally connected by bolt 79 to connection arm 80 which is connected to a rear carrier 81 by bolt 82. The carrier 81 is also pivotally connected at point 83 to mounting plate 75a. The bolt 82 also secures the bottom of a spring 84 and associated rod 85 passing through the centre of the spring. The top of the spring 84 is retained in compression by a cap portion 86 acting against the mounting plate 75a. A nut threaded on rod 85 also acts against the mounting plate 75a and limits expansion of the spring 84. As illustrated in Figure 12, if the tine 30 encounters an obstruction 88 (or hard ground) the various components move in the direction of arrows 89 permitting the tine 30 be bent backwards compressing the spring 89.

The tine mounting illustrated in Figures 11 and 12 shares some of the same components as the tine mounting 89 illustrated in Figure 1A and 13 for the rear mounted tines 31 and this thus ensures that both the forward tines 30 mounted on mountings 74 and rear tines 31 mounted on mountings 89 have the same performance characteristics and minimise the number of different part types required to provide both forward and aft mounting on a single transverse beam.

As stated, illustrated embodiments of the invention are provided by way of example only and the skilled person will realise that many modifications can be made without departing from the scope of the appended claims.

Claims

1. A cultivator comprising a drawbar, a main frame, at least one sub frame and at least two wheels, wherein:

the cultivator has a longitudinal direction and a width direction with the drawbar attached at a front end of the main frame so that the cultivator can be towed in the longitudinal direction;

the main frame comprises at least two parallel longitudinal frame side members spaced from each other in the width direction, each side member having a plurality of first engaging members;

the wheels are mounted on a sub frame, the sub frame having a plurality of second engaging members arranged to engage with the first engaging members at a plurality of different locations on the main frame, to permit the wheels to be mounted to the main frame at any one of a plurality of different locations in the longitudinal direction.

2. A cultivator as claimed in Claim 1, further comprising a plurality of sub frames at least some of which have a plurality of tools attached thereto, which sub frames have second engaging members so that they can be mounted to the side members at any one of a plurality of locations in the longitudinal direction.

3. A cultivator as claimed in Claim 1 or 2, wherein each of said side members comprises a strip of flat steel plate arranged in a vertical plane so that it may flex in the width direction of the cultivator, the side members being connected to a substantially rigid front cross member attached to the drawbar.

4. A cultivator comprising a drawbar, a main frame, a plurality of sub frames having tools attached thereto and at least two wheels, wherein:

the cultivator has a longitudinal direction and a width direction with the drawbar attached at a front end of the main frame so that the cultivator can be towed in the longitudinal direction; the main frame comprises at least two parallel longitudinal frame side members spaced from each other in the width direction, each side member having a plurality of first engaging members;

the sub frames have second engaging members so that they can be mounted to the side frames at any one of a plurality of locations in the longitudinal direction; and

each of said side members is formed from a strip of flat steel plate arranged in a vertical plane so that it may flex in the width direction of the cultivator, the side members being connected to a substantially rigid front cross member attached to the drawbar.

5. A cultivator as claimed in any preceding claim, wherein the first engagement members are equally spaced over at least half of the length of the longitudinal frame members.

6. A cultivator as claimed in any preceding claim, wherein the sub frames are lowered into the main frame.

7. A cultivator as claimed in any preceding claim, further comprising locking mechanisms for locking the sub frames in position on the main frame without the use of tools.

8. A cultivator as claimed in any preceding claim, wherein the first engaging members are in the form of a rack and each sub frames is in the form of a beam having a plurality of teeth at each end arranged to engage with respective racks of respective side members.

9. A cultivator as claimed in any preceding claim, wherein the main frame comprises a central section and two side sections, each of the central and side sections comprising respective pairs of side members with a front cross member and at least one sub frame extending there between, with the longitudinal frame members of the central section being hinged to adjacent longitudinal frame members of respective adjacent side sections to permit the side sections to be folded on the main section.

10. A cultivator as claimed in Claim 9, wherein the central section is approximately twice the width of the side sections and the side section can be folded through at least 135° to lie above the central section.

11. A cultivator as claimed in Claim 9 or 10, wherein each of the sections of the frame has a set of wheels mounted on a respective sub frame, the cultivator further comprising rams connected between the central wheel carrying sub frame and respective side section wheel carrying sub frames, wherein the rams are arranged to act between the respective wheel carrying sub frames to cause the side section sub frames to be folded or extended, folding or extending the side sections of the main frame to which the wheel carrying sub frames are engaged

12. A cultivator as claimed in any preceding claim, wherein the total tread width of the wheels is greater than 50 percent of the width of the main frame.

13. A cultivator as claimed in any preceding claim, further comprising a ram acting to raise or lower the wheels relative to the sub frame.

14. A cultivator as claimed in any preceding claim, comprising a packer mounted to the rear of the frame, which packer can be fixed in a lowered position so that when the wheels are raised the packer supports at least a portion of the weight of the cultivator, or set to float, where the packer does not support the weight of the cultivator.

15. A cultivator as claimed in any preceding claim, wherein the wheels are mounted on a sub frame which can be released from the main frame, the sub frame raised so that the first and second engaging members disengage and the wheels and sub frame slid forwards or backwards in the main frame.

16. A cultivator as claimed in any preceding claim, wherein each sub frame comprises box section tube extending in the width direction, terminating at its ends in respective steel plates transverse to the tube and welded thereto, the plates having second engaging members formed along there lower edge for engaging with the first engaging members on respective side members.

17. A cultivator comprising a transverse beam having a plurality of tine mountings thereon, each tine mounting comprising a tine, a mounting attaching the tine to the transverse beam of the cultivator and a coil spring acting to maintain the tine in a working position, wherein each tine is held by a respective mounting such that the tine is either mounted forward or aft of the beam, with alternate tines mounted fore and aft along the length of the beam.

18. A cultivator as claimed in Claim 17, wherein each tine mounting comprises a mounting plate and a carrier for the tine, wherein the mounting plate is mounted on the transverse beam of the cultivator, the mounting plate having the carrier pivotally connected thereto in which carrier the tine is held, the spring acting between the mounting plate and the carrier to urge the carrier against a stop where the tine is located in a desired working position, the carrier pivoting against the action of the spring when in use the tine exerts a sufficient force on the carrier.

19. A cultivator as claimed in Claim 18, wherein the tine mountings for the tines mounted forward of the beam have the carrier plate located forward of the beam and wherein the spring is a compression spring located above the position of the beam, transverse to the beam, the spring being held at a forward end by a mounting plate with an aft end of the spring being held in place by a linkage, the linkage being pivotally connected at spaced locations to both the spring and a mounting plate, the mounting further comprising a connecting rod connected at a forward end to the carrier and at an aft end to the linkage, whereby rotation of the carrier causes the connecting rod to rotate the linkage and compress the spring.

20. A cultivator as claimed in any one of Claims 17 to 19, wherein the mountings for the tines mounted forward of the beam and the mountings for the tines mounted aft of the beam, share common components so that the tines mounted forward of the beam have the same performance characteristics as the tines mounted aft of the beam.

21. A cultivator as claimed in any one of Claims 1 to 16, comprising a plurality of sub frames which have second engaging members so that they can be mounted to the main frame at any one of a plurality of locations in the longitudinal direction, wherein the sub frames are in the form of transverse beams and have tine mountings in accordance with any one of Claims 17 to 20 mounted thereon.

22. A cultivator comprising: a frame to which tools can be attached, a set of wheels; an axle supporting at least one wheel; a trailing arm connecting the axle to the frame; and a ram acting directly or indirectly between the frame and axle to raise and lower the wheels relative to the frame, the cultivator further comprising a scraper located behind the at least one wheel and/or a multipoint linkage for attaching farm implements, the scraper and/or multipoint linkage being supported by a hub on the axle, the cultivator further comprising a linkage mechanism arranged to retain the scraper and/or multipoint linkage with a desired vertical alignment, irrespective of the position of the wheel relative to the frame.

23. A cultivator as claimed in Claim 22, wherein the total tread width of the wheels is greater than 50 percent of the width of the main frame.

24. A cultivator as claimed in Claim 22 or 23, wherein the linkage mechanism comprises said lower trailing arm extending from a lower point on the frame to the axle and a first upper trailing arm extending from a higher point on the frame to a pivot point above the hub, the first lower and a first upper trailing arms being linked by a first cross member pivotally connected to both the first upper and the first lower trailing arms at points between their ends, the geometry of the trailing arms and first cross member being arranged to maintain the pivot point above the hub substantially a constant distance above and substantially vertically in line with the hub, the linkage mechanism further comprising upper and lower extension arms extending respectively rearward of the pivot point above the hub and the hub to a second cross member to which they are pivotally connected at vertically separated points to form a substantially parallel linkage, wherein the scraper and/or multipoint linkage are supported by the second cross member.

25. A cultivator as claimed in Claim 24, further comprising a ram for the linkage mechanism connected directly or indirectly between the frame and the linkage mechanism to control the height of the scraper and/or multipoint linkage relative to the bottom of the wheel irrespective of the position of the wheel relative to the frame.

26. A cultivator as claimed in Claim 25, wherein the linkage mechanism ram is arranged such that when actuated it will lift or lower the scraper and/or multipoint linkage and at its full extent of travel in one direction will determine the scraper and/or multipoint linkage height relative to the bottom of the wheel.

27. A cultivator as claimed in Claim 26, further comprising a manual adjuster to control the height relative to the bottom of the wheel of the scraper and/or multipoint linkage when the linkage mechanism ram is at said full extent of travel.

28. A cultivator as claimed in any one of Claims 22 to 27, comprising a multipoint linkage and a drill attached to the multipoint linkage, the drill being arranged such that the sowing depth is set relative to the bottom of the wheel.

29. A cultivator as claimed in any one of Claims 1 to 16 or 20 , further comprising the features recited in any one of Claims 22 to 28 wherein at least one wheel, trailing arm and linkage mechanism are connected to a sub frame of the frame.