GB1591940A

GB1591940A - Soil cultivating implements

Info

Publication number: GB1591940A
Application number: GB24380/78A
Authority: GB
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1977-08-09
Filing date: 1978-05-30
Publication date: 1981-07-01
Also published as: DE2834670A1; FR2399789A1; IT1097930B; NL7708761A; IT7826438A0; FR2399789B1

Description

(54) IMPROVEMENTS IN OR RELATING TO SOIL CULTIVATING IMPLEMENTS (71) We, C. VAN DER LELY N.V., of 10, Weverskade, Maasland, The Netherlands, a Dutch Limited Liability Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to soil cultivating implements or machines of the kind which comprises at least one group of soil working members that is in the form of a row of those members which extends substantially perpendicular, or at least transverse, to the intended direction of operative travel of the implement or machine, the soil working members being carried by a subsidiary frame portion so as to be rotatable about corresponding non-horizontal axes when the implement or machine is in use and said frame portion being upwardly and downwardly displaceable, during such use, relative to a main frame portion that is provided with means to enable it to be coupled to a tractor or other operating vehicle of the implement or machine. The expression "implement(s) or machine(s)" will be shortened to "implement(s)" alone throughout the remainder of this specification for the sake of brevity.

According to the invention, there is provided a soil cultivating implement of the kind set forth, wherein the upward and downward displaceability of the subsidiary frame portion which carries said group of soil working members is provided by a linkage which is disposed wholly or principally in front of that frame portion with respect to said direction of operative travel, and wherein said linkage is constructed and arranged in such a way that, during operation of the implement, the axes of rotation of the soil working members of said group will always be maintained in attitudes in which they slope upwardly and rearwardly from the ground surface relative to the direction of travel of the implement at that time.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a rear elevation of the centre and of the right-hand side of soil cultivating implement in accordance with the invention; Figure 2 is a side view as seen in the direction indicated by an arrow II in Figure 1; Figure 3 is a rear elevation as seen in the direction indicated by an arrow III in Figure 2 but illustrates only certain parts of the implement, and Figure 4 is a plan view as seen in the direction indicated by an arrow IV in Figure 1.

Referring to the accompanying drawings, the soil cultivating implement that is illustrated therein comprises a central main frame portion 1 that includes two frame beams 2 and 3 that are located one behind the other with respect to the intended direction of operative travel of the implement which is indicated by an arrow A in Figure 2 of the drawings. The two frame beams 2 and 3 both extend substantially horizontally transverse, and usually (as illustrated) substantially horizontally perpendicular, to the direction A. The two beams 2 and 3 are rigidly interconnected by a pair of spaced tie beams 4 which tie beams 4 both extend substantially horizontally parallel to the direction A. The opposite ends of both the beam 2 and the beam 3 all carry, at their tops, a total of six lugs 5, there being one lug 5 per end of the beam 2 and two lugs 5 per end of the beam 3. Pivot pins 6 which are substantially horizontally aligned with one another in the direction A in two pairs, turnably connected the ends of two beams 7 to the lugs 5 at the ends of the beams 2 and turnably connect the ends of two beams 8 to the pairs of lugs 5 that are at the opposite ends of the beam 3. Each beam 7, and the corresponding beam 8 which is to the rear thereof, with respect to the direction A, form parts of a corresponding supporting structure 9, there thus being two of the supporting structures 9 which lie at oppo site sides of the central main frame portion 1, both supporting structures 9 being in substantially perpendicular, or at least, transversc, relationship with the direction A when the implement is disposed for use. The leading beam 7 of each supporting structure 9 is at a lower horizontal level than is the corresponding rear beam 8 (sce Figure 2) and is of larger cross-sectional area. In fact, each leading hollow frame beam 7 is of substantially square cross-section whereas each rear frame beam 8 is of substantially oblong cross-section, the beams 8 being more robust in construction than are the beams 7. That end of each frame beam 7 which is closest to the central main frame portion 1 is provided with an upwardly directed part which includes a substantially vertically disposed plate 10 of irregular quadrilateral shape.

That corner of each plate 10 which is furthest from the beam 7 to which a lower edge region of that plate is secured is turnably connected by one of the pivot pins 6 to the lug 5 which is at the top of the neighbouring end of the leading frame beam 2 of the central main frame portion 1.

The two frame beams 7 and 8 of each supporting structure 9 are interconnected by two spaced beams 11 that are parallel to one another and whose obliqucly extending longitudinal axes are contained in corresponding substantially vertical planes that are parallel or substantially parallel to the direction A. Substantially vertically disposed support plates 12 are secured to the two beams 7 of the two supporting structures 9 at location which arc towards the opposite ends of both beams 7. It can be seen in Figure 2 of the drawings that each support plate 12 extends both above and beneath the beam 7 concerned and projects rearwardly of that beam 7 to some extent with respect to the direction A. Upper and lower pivot pins 13 turnably connected the leading ends of upper and lower pairs of links 14 to locations that are close to the top, and to the bottom, of each support plate 12.

The rearmost ends of the pairs of links 14, with respect to the direction A, are turnably connected by further upper and lower pivot pins 15 to upper and lower locations on a corresponding substantially vertical support 16. The four supports 16 are fixedly secured, in two pairs, to the tops of corresponding hollow box-section subsidiary frame portions 17 which subsidiary frame portions 17 both extend, when the imple mcnt is in use as illustrated in full lines in the accompanying drawings, substantially horizontally transverse, and usually (as illustrated) substantially horizontally perpendicular, to the direction A. It will be clear from the drawings that the pivots 13 and 15 and the links 14 form parts of dual pivotable linkages which, in the embodiment that is being described, are in the form of parallelogram linkages 18 which linkages allow the subsidiary frame portions 17 to move upwardly and downwardly relative to the corresponding supporting structures 9 which latter lie generally above the two subsidiary frame portions 17. It will be particularly noted from Figure 2 of the drawings that the leading upper and lower pivot pins 13 of each dual parallelogram linkage 18 are not exactly vertically one above the other but are so disposed that their longitudinal axes can be interconnected by a line a which is inclined to the strictly vertical in such a way that an imaginary point on the line a near the bottom of the implement is further advanced with respect to the direction A than is a second imaginary point on the same line a but that is near the top of the implement. The angle of inclination of the line a to a strictly vertical plane A-A (Figure 2) advantageously has a magnitude of between 3 and 5 inclusive. Each dual parallelogram linkage 18 is so constructed that the longitudinal axes of the rear pivot pins 15 which correspond to each two pairs of links 14 can be interconnected by a second line a (Figure 2) which is parallel to the corresponding first line a that has just been discussed and that is, therefore, similarly inclined to the plane A-A.

Each leading frame beam 7 of each supporting structure 9 is connected to a bracket which depends from the corresponding rear frame beam 8 by two parallel and closely spaced apart strips 19A, said strips 19A being parallel or substantially parallel to the direction A and being so positioned that the outer support 16 (i.e. the support 16 which is furthest from the central frame portion 1) of the corresponding subsidiary frame portion 17 is slidably sandwiched between them. Each pair of strips 19A thus affords a guide which prevents, or at least greatly minimises, movement of the corresponding subsidiary frame portion 17 in directions that are transverse to the direction A when the implement is in use. Moreover, the strips 19A serve as stops to prevent the subsidiary frame portions 17 from moving too far upwardly, or downwardly, relative to the structures 9 since the upper and lower edges of said strips 19A limit upward and downward movements of the rear pivot pins 15 of the dual parallelogram linkages 18 and of the upper and lower links 14 thereof. Flexible but inextensible members in the form of chains 19B are provided alongside the two supports 16 which are closest to the central frame portion 1 and these chains 19B afford limiting members which act to prevent the ends of the subsidiary frame portions 17 concerned from moving too far downwardly relative to the corresponding structures 9.

A plurality (in this case, twelve) of shafts 19 whose axes are non-horizontally disposed when the implement is in use are arranged in a single row in each of the two sub sidiary frame portions 17, the longitudinal axes of the shafts 19 that correspond to each subsidiary frame portion 17 being spaced apart from one another at regular intervals which advantageously, but not essentially, have magnitudes of substantially 250 millimetres. Each shaft 19 projects downwardly from beneath the bottom of the corresponding subsidiary frame portion 17 and there has a hub at the centre of a substantially horizontally disposed support or carrier 20 firmly but releasably secured to it by means which conveniently comprises co-operating splines and a fastening nut (see Figure 2) that is mounted on a short screwthreaded lowermost extremity of the shaft 19 concerned. Means, such as a split pin or the like, is preferably provided to prevent each fastening nut from working loose when the implement is in use. The opposite ends of each support or carrier 20 integrally, or at least rigidly, carry corresponding substantially cylindrical sleeve-like tine holders in which fastening portions at the upper ends of a corresponding pair of rigid soil working tines 21 are firmly but releasably secured. Each tine 21 has a soil working portion that projects downwardly into the ground, when the implement is in use, from substantially the lowermost end of the corresponding holder. Preferably, the fastening portion and soil working portion of each tine 21 are both straight and are inclined to one another, at the junction between them, by a small angle of, for example, 8". The tines 21 are arranged in their holders so that the soil working portions thereof trail rearwardly from the top to bottom with respect to the intended directions of operative rotation of rotary soil working members 22 which are afforded by the supports or carriers 20, the tine holders and the tines 21.

Means (not illustrated) is provided to prevent each tine 21 from turning about the longitudinal axis of its fastening portion once that fastening portion is firmly secured in the corresponding holder. It will be apparent that, since the soil working members 22 are secured to the lowermost ends of the shafts 19, their axes of rotation correspond with those of said shafts 19. Each individual soil working member 22 preferably has dimensions which are such that it will work a strip of land, extending in the direction A, that has a width of substantially 300 millimetres so that, with the preferred spacing of substantially 250 millimetres between the longitudinal axes of immediately neighbouring shafts 19 that has been mentioned above, the strips of the soil which are worked by immediately neighbouring members 22 will overlap one another to form, in effect, a single broad strip of worked soil that corresponds to the subsidiary frame portion 17 concerned. The neighbouring ends of the two subsidiary frame portions 17 are so close to one another when the implement is in use that the two broad strips of land which are worked thereby at least adjoin, if not actually overlap, one another so that the implement is capable or working a single substantially unbroken broad strip of land which, with the dimensions that have been referred to in respect of the described and illustrated embodiment, will have a width of substantially 6 metres.

Reference to Figure 2 of the drawings will make it clear that, when the implement is in operation, the longitudinal axes of the twelve shafts 19 which correspond to each subsidiary frame portion 17 are contained in a plane B-B which is parallel to the corresponding lines m and which is thus inclined to the aforementioned strictly vertical plane A-A by a small angle which will preferably have a magnitude of between substantially 3" and substantially 5" inclusive. Since the plane B-B that can be seen in Figure 2 of the drawings in parallel to the corresponding lines a, the point at which it intersects the ground surface is further advanced, with respect to the direction A, than is an imaginary point on said plane which is near to the top of the implement. Since the tow subsidiary frame portions 17 are in end-to-end relationship when the implement is in use, what has been said concerning the relative dispositions of the lines a and planes A-A and B-B is usually true, during operation, for both subsidiary frame portions 17 and all twentyfour of the soil working members 22. The ends of the two subsidiary frame portions 17 which are remote from the central main frame portion 1 are provided with corresponding shield plates 24 each of which shield plates, when the implement is in use, occupies a position substantially corresponding to that which is illustrated for one of them in Figure 2. Thus, each shield plate 24 is substantially vertically disposed in parallel or substantially parallel relationship with the direction A, the shape thereof being such that its lower edge can slide forwardly in the direction A during operation or rearwardly with respect to that direction during manoeuvring. The upper edge of each shield plate 24 is connected by a corresponding arm 23, which is bent into the shape that is shown in the drawings, to two brackets that are mounted on top of the subsidiary frame portion 17 concerned and that are formed with openings which are substantially horizontally aligned in a direction which is parallel or substantially parallel to the direction A. A straight por tion of the arm 23 concerned is entered turnably through the aligned openings in the two brackets and it will be clear from a sludy of the drawings that this allows the corresponding shield plate 24 to turn upwardly and downwardly about the longitudinal axis of said arm portion to match undulations in the surface of the ground that may be met with by the lower edge of the shield plate 24 during operative progress in the irection A. The shield plates 24 co-operate with the neighbouring rotary soil working members 22 at the opposite ends of the row of twenty-four such members in ensuring that soil located close to the edges of the broad strip of land which is cultivated by the implement is as well crumbled or otherwise worked as is soil with its disposed closed to the centre of the broad strip. The shield plates 24 minimise ridging of the soil at the margins of the broad strip of worked land and also prevent stones and other hard objects from being flung laterally of the path of travel of the imple ment by the tines 21 of the rapidly rotating soil working members 22. The danger of injury or damage to bystanders, livestock and property from this cause is thus very grcatly reduced, if not entirely eliminated.

The rear frame beams 8 of the two supporting structures 9 both carry, close to their opposite ends. upright supports 25 that are of hollow formation and inside which cor responding carriers 26 are upwardly and downwardly displaceable in such a way that the extent of projection of said carriers 26 from the lower open ends of the upright supports 25 is adjustable. This adjustment is effected by manually rotating crank handles 27 that are mounted at the upper ends of the supports 25. The assemblics 25, 26 27 are well known per se and, in any case, do not require detailed description for the purpose of the present invention. The lower ends of the two carriers 26 which project from the bottoms of the two upright supports 25 which correspond to each supporting structure 9 are interconnected by a corresponding beam 28 which, when the implement is in operation, extends substantially horizontally perpendicular, or at least transverse, to the direction A. Each beam 28 has a length which is greater than the spacing between the corresponding carriers 26 and thus projects beyond those carriers to locations which are substantially in registcr, in the direction A, with the opposite ends of the corresponding subsidiary frame portion 17. Arms 29 project substantially vertically downwards from the opposite ends of each beam 28 and their lower ends carry substantially horizontally aligned bearings between which a corresponding open-work ground roller 30 is mounted in a frcely rotatable manner There are thus two of the rollers 30 each of which comprises a central axially extending and preferably tubular support to which a plurality of substantially circular and substantially vertically disposed support plates are fastened at regularly spaced apart intervals The support plates are formed, close to their peripheries, with a plurality, such as eleven, of regularly spaced apart holes and elongate elements 31 which are of either rod or tubular formation are entered lengthwise through the holes in the successive support plates along the roller 30 concerned in such a way that, as can be seen in Figure 4 of the drawings, said elements 31 extend in shallow helically wound relationship around the central support, and thus the axis of rotation, of the roller 30 concerned The rollers 30 are bodily upwardly and downwardly adjustable in position relative to the corresponding supporting structures 9 by appropriate manipulation of the corresponding crank handles 27, said rollers 30 acting as rotatable supporting members of the structures 9, and thus of the corresponding soil working members 22, and also acting, in their own right, as soil working members which will crush any exceptionally unbroken lumps of soil that may be left lying upon the ground surface by the foregoing soil working members 22, the soil work by those members 22 being distributed, levelled and gently compressed to some extent by the rollers 30 The front of the central main frame por tion 1, with respect to the direction A, is provided with a coupling member or trestle 32 that is of substantially triangular configuration as seen in front (Figure 1) or rear elevation The coupling member or trestle 32 comprises two horizontally spaced apart lower coupling points an a single upper coupling point that are constructed and arranged for use, in a manner that is generally known per se, in connecting the central main frame portion 1 of the implement to the three-point lifting device or hitch at the rear of an agricultural tractor or other operating vehicle Substantially the apex of the coupling member or trestle 32 is indirectly connected to locations that are close to the opposite ends of the rear frame beam 3 of the central main frame portion 1 by downwardly and rearwardly divergent tie strips 33 The tie beams 4 that interconnect the front and rear frame beams 2 and 3 of the central main frame portion 1 are provided, towards their rear ends, with up wardly divergent supports 34 The two upwardly divergent supports 34 are interconnected towards, but not at, their upper ends by a substantially horizontal beam 35 (Figure 1) which extends substantially perr pendicular, or at least transverse, to the direction A. The front, with respect to the direction A, of the transverse beam 35 has two hooks 37 pivotally connected to it by substantially horizontal pins 36, that are substantially parallel to the direction A, said hooks 37 and pins 36 being located close to the opposite ends of the beam 35 in positions which are such that said hooks 37 project across the fronts of the two supports 34 and normally have their lower edges in downwardly abutting contact with stops 38 that are fastened to the fronts of the two supports 34. The hooks 37 are arranged to co-operate retainingly with anchorages 39, in the form of beams, which anchorages 39 extend between the plates 10 and further parallel plates 40 carried by the rear beams 8 of the two supporting structures 9. Such co-operation takes place when the two supporting structures 9, and the parts which they carry, are tilted upwardly about the axes defined by the pivot pins 6 into the broken line positions which are illustrated in Figure 1 of the drawings. When the implement occupies the position that is shown partly in broken lines in Figure 1 of the drawings, its width is very considerably reduced as compared with the position that is shown in full lines, such broken line position being suitable for inoperative transport of the implement when supported by the three-point lifting device or hitch at the rear of an agricultural tractor or other vehicle.

The two supporting structures 9, and the parts which they carry, are tilted upwardly into the positions thereof that are shown in broken lines in Figure 1 of the drawings by a hydraulic piston and cylinder assembly 41 whose arrangement can be seen best in Figure 3. The cylinder of the assembly 41 is substantially horizontally disposed at a location just beneath the rear frame beam 3 or the central main frame portion 1 and has opposed piston rods which project from its opposite ends. The free ends of the piston rods of the assembly 41 are pivotally connected to corresponding plates 42 that are welded or otherwise rigidly secured to the bottoms of the rear beams 8 of the two supporting structures 9 at the ends of those beams 8 which are closest to the central main frame portion 1. Flexible but inextensible members in the form of chains 43 interconnect brackets mounted at the upper ends of the upwardly divergent supports 34 and further brackets which are secured to the anchorages 39 which interconnect the plates 10 and the further plates 40 of the two supporting structures 9. The chains 43, when they become taut, prevent the supporting structures 9 and the parts which they carry from turning too far downwardly relative to the central main frame portion 1 about the axes which are defined by the respective pairs of pivot pins 6. A gear box 45 is mounted in the middle of the central main frame portion 1 and is secured to underlying supports 44 which supports, in turn, are secured to the two tie beams 4.

The gear box 45 includes a shaft 46 which extends substantially horizontally parallel to the direction A and whose leading splined or otherwise keyed end projects forwardly from the front of the gear box so that the shaft 46 can serve as a rotary input shaft.

The forwardly projecting end of the shaft 46 is intended to be placed in driven connection with a rear power take-off shaft of an agricultural tractor or other operating vehicle of the implement by way of an intermediate telescopic transmission shaft (not shown), which is of a construction that is known per se, having universal joints at its opposite ends. The shaft 46 extends through the gear box 45 and its rear end, together with the rear end of an underlying and parallel shaft that is not visible in the drawings, projects into a change-speed gear 47 which is mounted at the back of the gear box 45 with respect to the direction A. It is not necessary to describe or to illustrate the construction and arrangement of the change-speed gear 47 in any detail for the purposes of the present invention and it suffices to say that the shaft ends which project into the change-speed gear 47 are both splined and are arranged interchangeably to receive the matchingly splined hubs of a pair of co-operating pinions of different sizes. Preferably, at least one other pair of pinions of other different sizes is provided which can be exchanged for the first mentioned pair. It will be appreciated that the pair of pinions which is selected for use in the change-speed gear 47, and the arrangement thereof that is made on the shaft ends in question, dictates the transmission ratio between the rotary input shaft 46 and the underlying and parallel shaft that is not visible in the drawings. The latter shaft idirectly drives all of the rotary soil working members 22 when the implement is in use so that the speed of rotation of those members can be changed, by employing the change-speed gear 47, without it being necessary to alter the speed of driving rotation that is applied to the input shaft 46 by way of a bevel pinion transmission. The free opposite ends of the output shaft 48 of the gear box 45 are connected by universal joints to the ends of corresponding telescopic transmission shafts 50 and the other ends of said shafts 50 are in turn, connected by further universal joints to input shafts 51 of two gear boxes 52. When the implement is in use, the input shafts 51 of the gear boxes 52 are substantially horizontally disposed whereas the telescopic transmission shafts 50 extend obliquely between the opposite ends of the shaft 48 and said input shafts 51 (see Figure 1 - full line position). The two gear boxes 52 are mounted on top of the two subsidiary frame portions 17 at locations which are close to the centres of those two frame portions. la fact, as can be seen in the drawings, each gear box 52 lies above a corresponding one of the rotary soil working members 22 and the shafts 19 which correspond to those two soil working members 22 both have upward extensions through the tops of the corresponding subsidiary frame portions 17 into the gear boxes 52 concerned. Bevel pinions (not visible) within the gear boxes 52 place the upward shaft extensions which have just been mentioned in driven connection with the rotary input shafts 51 of the two gear boxes 52. Each shaft 19 carries, inside the corresponding subsidiary frame portion 17, a straighttoothed or spur-toothed pinion, the size and arrangement of the pinions being such that the teeth of each of them are in mesh with those of the or each immediately neighbouring pinion that corresponds to the same subsidiary frame portion 17. Thus, when the implement is in use, each pinion, together with the corresponding shaft 19 and soil working member 22, will revolve in the opposite direction to the or each immediately neighbouring pinion of the same subsidiary frame portion 17.

In the use of the soil cultivating implement that has been described, its coupling member or trestle 32 is connected to the three-point lifting device or hitch at the rear of an agricultural tractor or other operating vehicle and the leading end of the rotary input shaft 46 or the gear box 45 is placed in driven connection with a power take-off shaft at the rear of the same tractor or other operating vehicle. Adjustments which may, if necessary, be made before work commences include changing the speed at which the soil working members 22 will revolve, in response to a substantially standard speed of rotation applied to the input shaft 46, by appropriate alteration to the change-speed gear 47. The rollers 30 may, if required, be bodily raised or lowered in position relative to the supporting structures 9, these adjustments being made primarily in regard to the nature and condition of the soil that is to be dealt with and the particular purpose for which that soil is required after cultivation. As previously discussed, the soil working members 22 work overlapping strips of soil during operative progress in the direction A to produce two broad strips of worked land which at least adjoin, if not actually overlap. one another thus forming the two strips which correspond to the two subsidiary frame portions 17 and corresponding groups of soil working members 22 into a single substantially unbroken broad strip of worked land. Due to the arrangement of the dual parallelogram linkages 18 which has been described above, the axes of rotation of the soil working members 22 will be contained in the plane B-B during operative progress in the direction A, said plane B-B being inclined to the strictly vertical plane A-A by an angle of between 3 and 5 inclusive in such a way that each axis of rotation extends upwardly and rearwardly with respect to the direction A from the ground surface at said inclination to the strictly vertical. This arrangeme subject to the presure of oil or other fluid pressure medium. Advantageously, a member (not shown) that is actuable from the .driving seat of the agricultural tractor or other operating vehicle is connected to the two hooks 37 so that said hooks can be lifted, by that member, out of their retaining engagement with the two anchorages 39 when the implement is to resume operation at a new site or after manoeuvring. The hydraulic piston and cylinder assembly 41, which is preferably but not essentially of a double-acting construction, is then operated to withdraw the two piston rods inwardly into the cylinder so that the two supporting structures 9 are gently returned downwardly and outwardly back into the working position that is shown in full lines in the drawings. It is not essential for the assembly 41 to be of a double-acting construction.

WHAT WE CLAIM IS: 1. A soil cultivating implement of the kind set forth, wherein the upward and downward displaceability of the subsidiary frame portion which carries said group of soil working members is provided by a linkage which is disposed wholly or principally in front of that frame portion with respect to said direction of operative travel, and wherein said linkage is constructed and arranged in such a way that, during operation of the implement, the axes of rotation of the soil working members of said group will always be maintained in attitudes in which they slope upwardly and rearwardly from the ground surface relative to the direction of travel of the implement at that time.

2. An implement as claimed in claim 1, wherein, when the implement is in operation on strictly horizontal ground, a plane which contains the axes of rotation of said group of soil working members is inclined to a strictly vertical plane which extends perpendicular, or at least transverse, to the intended direction of operative travel of the implement at an angle of between 3 and 5 , inclusive.

3. An implement as claimed in claim 1 or 2, wherein said linkage is a pivotable linkage.

4. An implement as claimed in claim 3, wherein said pivotable linkage is a dual pivotable linkage, the two portions thereof being located adjacent to the opposite ends of the subsidiary frame portion.

5. An implement as claimed in claim 3 or 4, wherein the pivotable linkage is a parallelogram linkage which is so constructed that upright lines interconnecting front pivot points and rear pivot points thereof, respectively, are in parallel or substantially parallel relationship with a plane which contains the axes of rotation of said group of soil working members.

6. An implement as claimed in claim 5, wherein the lower pivot points of said parallelogram linkage are in advance of the corresponding upper pivot points thereof with respect to the intended direction of operative travel of the implement.

7. An implement as claimed in any preceding claim, wherein the main frame portion has two supporting structures connected to its opposite sides, each supporting structure carrying a corresponding upwardly and downwardly displaceable subsidiary frame portion and each such subsidiary frame portion supporting a corresponing group of the rotary soil working members, and wherein the construction an arrangement of said subsidiary frame portions and supporting structures are such that, when the implement is in use, the subsidiary frame portions extend in end-to-end relationship so that the corresponding groups of soil working members cultivate overlapping, or at least substantially adjoining, strips of ground.

8. An implement as claimed in claim 7, wherein each subsidiary frame portion is upwardly and downwardly displaceable relative to the corresponding supporting structure by way of a corresponding linkage.

9. An implement as claimed in claim 7 or 8, wherein each supporting structure is pivotable relative to the main frame portion about a corresponding axis that extends substantially horizontally parallel to the intended direction of operative travel of the implement.

10. An implement as claimed in any one of claims 7 to 9, wherein each supporting structure is arranged so that it can be moved into a non-horizontally disposed position which is suitable for the inoperative transport of the whole implement.

11. An implement as claimed in claim 9 or in claim 10 when read as appendant to claim 9, wherein the two pivotable supporting structures are interconnected by a substantially horizontally disposed fluid pressure operable piston and cylinder assembly.

12. An implement as claimed in claim 11, wherein said assembly is located beneath part of the main frame portion.

13. An implement as claimed in claim 7 or in any one of claims 8 to 12 when read as appendant to claim 7, wherein the main frame portion is also provided with retaining mechanism that is arranged automatically to maintain said supporting structures in the positions thereof that are suitable for inoperative transport of the whole implement.

14. An implement as claimed in claim 13, wherein the retaining mechanism comprises at least one pivotally mounted hook that is arranged to co-operate with an anchorage on the corresponding supporting structure.

15. An implement as claimed in any one of claims 7 to 14, wherein each supporting

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. subject to the presure of oil or other fluid pressure medium. Advantageously, a member (not shown) that is actuable from the .driving seat of the agricultural tractor or other operating vehicle is connected to the two hooks 37 so that said hooks can be lifted, by that member, out of their retaining engagement with the two anchorages 39 when the implement is to resume operation at a new site or after manoeuvring. The hydraulic piston and cylinder assembly 41, which is preferably but not essentially of a double-acting construction, is then operated to withdraw the two piston rods inwardly into the cylinder so that the two supporting structures 9 are gently returned downwardly and outwardly back into the working position that is shown in full lines in the drawings. It is not essential for the assembly 41 to be of a double-acting construction. WHAT WE CLAIM IS:

1. A soil cultivating implement of the kind set forth, wherein the upward and downward displaceability of the subsidiary frame portion which carries said group of soil working members is provided by a linkage which is disposed wholly or principally in front of that frame portion with respect to said direction of operative travel, and wherein said linkage is constructed and arranged in such a way that, during operation of the implement, the axes of rotation of the soil working members of said group will always be maintained in attitudes in which they slope upwardly and rearwardly from the ground surface relative to the direction of travel of the implement at that time.

structure and the main frame portion are interconnected by a member that is arranged to prevent said supporting structure from moving downwardly relative to said main frame portion beyond a predetermined limit.

16. An implement as claimed in any one of claims 7 to 15, wherein the subsidiary frame portions are provided, adjacent to their opposite ends, with means to prevent them from moving downwardly relative to the corresponding supporting structures beyond predetermined limits.

17. An implement as claimed in claim 16, wherein one of said limiting means for each subsidiary frame portion comprises at least one rigid member whereas the other limiting means comprises a flexible but inexten siblc member.

18. An implement as claimed in claim 17, wherein the flexible but inextensible limiting member is located adjacent to the end of the subsidiary frame portion concerned which is closcst to the main frame portion.

19. An implement as claimed in any one of claims 7 to 18, wherein a rotatable supporting member is arranged behind each group of soil working members with respect to the intended direction of operative travel of the implement, each supporting member being arranged to bear upon the ground surface during the operation of the implement.

20. An implement as claimed in claim 19, wherein each supporting member is bodily upwardly and downwardly displaceable in position relative to the corresponding supporting structure and is in the form of an open-work roller that extends throughout substantially the whole of the working width of the corresponding group of soil working members and whose soil engaging periphery is afforded principally by a plurality of elongate elements.

21. An implement as claimed in claim 20, wherein each roller is upwardly and downwardly displaceable in a vertical direction.

22. An implement as claimed in any one of claims 7 to 21, wherein each of the subsidiary frame portions is of hollow construction, the interior thereof accommodating parts of a drive transmission to the rotary soil working members of the corresponding group.

23. An implement as claimed in claim 22, wherein said drive transmissions to the two groups of rotary soil working members also include telescopic shafts that extend lengthwise of the two subsidiary frame portions, said telescopic shafts being coupled to further transmission members that are carried by the main frame portion, and wherein said further transmission members include a rotary input shaft that is connectible to the power take-off shaft of an agricultural tractor or other operating vehicle of the implement.

24. A soil cultivating implement of the kind set forth, substantially as hereinbefore described with reference to the accompanying drawings.