GB1587736A - Soil cultivating implements - Google Patents

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 that will hereinafter be referred to principally only as "implements" for the sake of brevity, such implements being of the kind which comprise a plurality of soil working members arranged in a row that extends transverse to the intended direction of operative travel of the implement so as to be rotatable about corresponding non-horizontal axes, at least one ground roller being disposed to the rear of the row of soil working members with respect to said direction with said roller extending throughout substantially the whole of the working width of the row of soil working members.

According to the invention, there is provided a soil cultivating implement of the kind set forth, wherein two ground rollers are provided whose intended axes of rotation are disposed one behind the other in said direction at locations to the rear of said row of the soil working members, said two rollers being of different effective diameters and both of them being bodily pivotable, in common, relative to a frame portion of the implement by the displacement of carriers to which the rollers are connected.

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 plan view of a soil cultivating implement in accordance with the invention connected to the rear of an agricultural tractor Figure 2 is a side elevation as seen in the direction indicated by an arrow II in Figure I, Figure 3 is a plan view, to an enlarged scale, showing one lateral side of an implement in accordance with the invention which implement has, however, an alternative construction to the implement of Figures 1 and 2 of the drawings, Figure 4 is a side elevation as seen in the direction indicated by an arrow IV in Figure 3, and Figure 5 is again a side elevation as seen in the direction indicated by the arrow IV in Figure 3 but illustrates a modification of the implement of Figures 3 and 4 of the drawings.

Referring to Figures 1 and 2 of the drawings, the soil cultivating implement that is illustrated therein has a hollow box-section frame portion 1 that extends substantially horizontally transverse, and usually substantially horizontally perpendicular (as illustrated), to the intended direction of operative travel of the implement that is indicated throughout the drawings by an arrow A. A plurality (of which there are twelve in the embodiment that is illustrated) of substantially vertical, or at least non-horizontal, shafts 2 are rotatably journalled in bearings carried by upper and lower walls of the frame portion 1 in such a way that said shafts 2 lie in a single row in parallel relationship with one another at regularly spaced apart intervals which are preferably, but not essentially, such that the longitudinal axes thereof are spaced apart from one another by distances of substantially 25 cms. Each of the rotatable shafts 2 projects downwardly beyond the bottom of the hollow frame portion 1 and there carries a corresponding soil working member that is generally indicated by the reference 3. Each soil working member 3 comprises a substantially horizontally disposed support or carrier 4 that is fastened, at its centre, to the corresponding shaft 2, the opposite ends of the support or carrier 4 being provided with sleeve-like holders in which fastening portions of rigid soil working tines 5 are firmly but releasably secured so that soil working portions of the tines 5 project downwardly into the earth that is to be cultivated by the implement when the latter is in use (see Figure 2).

The opposite ends of the hollow box section frame portion 1 are closed by corresponding substantially sector-shaped side plates 6 that are substantially vertically disposed in parallel relationship with each other and parallel or substantially parallel relationship with the direction A. The longer upright edges of the side plates 6 are disposed at the rear ends of those side plates with respect to the direction A, said side plates 6 being provided, close to their upper leading corners, with substantially horizontally aligned pivots 7 which define an axis that is parallel to the length of the frame portion 1 and thus perpendicular or substantially perpendicular to the direction A. Arms 8 are turnable upwardly and downwardly alongside the two plates 6 about the corresponding pivots 7, said arms 8 extending generally rearwardly with respect to the direction A from the pivots 7. The rear ends of the arms 8 are located behind the rear edges of the side plates 6 with respect to the direction A and each such rear end has the leading end of a corresponding carrier 9 secured to it in such a way that, as can be seen in Figures 1 and 2 of the drawings, each carrier 9 extends in substantial, but not exact, rectilinear rearward prolongation of the corresponding arm 8. Each carrier 9 has a corresponding support plate 10 fastened to it so as to project downwardly towards the ground therefrom, lower regions of the two support plates 10 being perpendicularly interconnected by a substantially horizontal shaft 12 whose longitudinal axis is contained in a plane that is parallel or substantially parallel to a plane which contains the longitudinal axes (axes of rotation) of all twelve of the shafts 2. A compacting roller that is generally indicated by the reference 11 is mounted in a freely rotatable manner on the shaft 12 and comprises a large number of substantially identical soil consolidating members in the form of discs 13. The discs 13 extend in side-by-side relationship along the shaft 12 and each of them is freely rotatable in either direction, independently of its fellows, around said shaft 12. The curved surface of the roller 11 that is afforded principally by the discs 13 thus defines a large number of angular more or less V-shaped recesses, the roller 11, and thus each of the discs 13, preferably having an effective diameter of substantially 30 cms.

The rearmost ends of the two carriers 9 with respect to the direction A are secured to opposite end regions of a tubular beam 9A that extends substantially horizontally parallel to the shaft 12 and to the transverse length of the hollow frame portion 1. The opposite extremities of the tubular beam 9A are provided with corresponding obliquely downwardly and rearwardly projecting arms 9B between the lowermost and rearmost ends of which a second roller 14 is mounted in a freely rotatable manner. The second roller 14 comprises a central axially extending support or carrier along which, at regular intervals, substantially vertically disposed hexagonal support plates are mounted so as to extend parallel to one another and parallel or substantially parallel to the direction A.

Elongate strip-shaped elements 15 are wound helically around the longitudinal axis of the second roller 14 and are conveniently, as illustrated, connected to the centres of the straight edges %f the hexagonal support plates. Each strip-shaped element 15 has an outwardly directed edge of saw-toothed or other serrated configuration (see Figure 1), the second roller 14 having an overall diameter of substantially 15 cms (i.e. substantially half the effective diameter of the compacting roller 11) and the distance between the two rollers 11 and 14 in substantially the direction A being about half the diameter of the second roller 14 (i.e. said distance having a magnitude of substantially 7.5 cms. in the embodiment that is being described).

Each of the shafts 2 that are rotatably mounted in the hollow frame portion 1 is provided, inside that frame portion, with a corresponding straight-toothed or spurtoothed pinion 16, said pinions 16 being arranged in a single row in such a way that the teeth of each of them are in mesh with those of the neighbouring pinion 16, or with those of both of the neighbouring pinions 16, in said row. One of the centre pair of shafts 2 in the row of twelve such shafts has an upward extension through the top of the hollow frame portion 1 into a gear box 17 that is fastened in position on top of the frame portion 1. The shaft extension carries a bevel pinion (not visible) inside the gear box 17 which pinion has its teeth in driven mesh with those of a further bevel pinion (not visible) mounted on a shaft (also not visible) that extends substantially horizontally parallel to the direction A. The rear end of this shaft and the rear end of an overlying and parallel shaft 18 both project through the rear wall of the gear box 17 into a changespeed gear 1 7A that is mounted at the back of the gear box 17. The ends of the two shafts that project into the change-speed gear 17A are both splined or otherwise keyed for cooperation with the matchingly splined or keyed hubs of interchangeable and/or exchangeable pairs of straight-toothed or spurtoothed pinions of different sizes. The particular pair of pinions that is chosen for use in the change-speed gear 17A, and the arrangement thereof that is selected on the splined or otherwise keyed shaft ends, dictates the transmission ratio between the shaft 18 and the underlying and parallel shaft that is not visible in the drawings and thus the speed at which all of the soil working members 3 will be rotated in response to a substantially constant speed of input rotation that is applied to the leading end of the shaft 18.

Said leading end of the shaft 18 projects forwardly in substantially the direction A from the front of the gear-box 17 and is splined or otherwise keyed to enable it to be placed in driven connection with the power take-off shaft at the rear of an agricultural tractor or other operating vehicle through the intermediary of a telescopic transmission shaft 19, which is of a construction that is known per se, having universal joints at its opposite ends. A central region of the front of the hollow frame portion 1 is provided with a coupling member or trestle 20 that is of generally triangular configuration as seen in front or rear elevation, said coupling member or trestle 20 being constructed and arranged for connecting the implement to the threepoint lifting device or hitch at the rear of the same agricultural tractor or other operating vehicle whose power take-off shaft is employed to drive the rotary soil working members 3 of the implement. Substantially vertically disposed shield plates 21 A that are in parallel or substantially parallel relationship with the direction A are provided at locations immediately beyond the opposite ends of the row of soil working members 3, each shield plate 21 A being connected by a corresponding pair of arms to a pair of pivots that are mounted on top of the hollow frame portion 1 so as to define an axis that is substantially horizontally parallel to the direction A. The lower edges of the shield plates 21 A are designed to slide either forwardly or rearwardly with respect to the direction A over the ground surface and the pivots by which said plates 21A are indirectly connected to the frame portion 1 enable the shield plates to move upwardly and downwardly during the operation of the implement to match undulations in the soil that is being cultivated thereby. The shield plates 21 A co-operate with the soil working members 3 at the opposite ends of the row thereof in cultivating the soil and minimising ridging thereof at the opposite edges of the broad strip of land that is worked by the implement and also greatly minimise, if not entirely prevent, stones and other potentially injurious or damaging items from being flung laterally of the path of travel of the implement by the rapidly moving tines 5 of the members 3. A protective and soil-levelling beam 21B of L-shaped cross-section is secured to arms in such a position that it extends substantially horizontally perpendicular to the direction A at a location just in front of the upper parts of all of the soil working members 3. The beam 21B is, in fact, arranged so as to be capable of yielding forwardly with respect to the direction A against the opposition of two helical tension springs that are mounted above the top of the hollow frame portion 1 in the manner that is illustrated somewhat diagrammatically in Figure 1 of the drawings. The yieldability of the beam 21B enables it to move forwardly to avoid damage in the event of a stone or other obstacle becoming momentarily jammed between its rear surface and at least one of the soil working members 3. Once such a stone or the like has been released upon forward movement of the beam 21B, its loading springs immediately return it to the undeflected position thereof that is illustrated in the drawings. A central region of the tubular beam 9A is provided with a pair of obliquely upwardly and rearwardly extending lugs 21 whose upper ends are pivotally connected by substantially horizontally aligned pins 22 to the limbs of a fork 24A. The base of the fork 24A is fastened to one end of a rod 24 which projects obliquely upwardly and forwardly with respect to the direction A towards the top of the coupling member or trestle 20. The rod 24 has a screw-threaded extension and a rod that is formed with an oppositely wound screwthread projects from a pivotal mounting at the top of the coupling member or trestle 20 towards said rod 24. The screwthreaded extension of the rod 24 and the rod that is formed with the oppositely wound screwthread are entered into opposite ends of a sleeve 25 that is formed internally with oppositely wound and matching screwthreads. Thus, in known manner, the sleeve 25 can be revolved around its own longitudinal axis to increase, or decrease, the distance of the fork 24A from the top of the coupling member or trestle 20 depending on the direction in which said sleeve 25 is turned.

One end of a bridge arm 23 is rigidly secured to the tubular beam 9A at a location close to the two lugs 21, said bridge arm 23 extending forwardly from the beam 9A to have its leading ends pivotally connected to a lug that is mounted on the frame portion I, the axis of the pivotal connection being coincident, or substantially coincident, with the substantially horizontal axis that is defined by the two pivots 7. Curved rows of holes 23B are formed close to the rear edges of the two side plates 6 at equal distances from the axis that is defined by the pivots 7 and the two arms 8 are formed with single holes which are spaced from said axis by the same distance as are the holes 23B. Bolts 23A or like fastenings are provided for entry through the single holes in the arm 8 and chosen ones of the holes 23B to maintain said arms 8, and the rollers 11 and 14 that they indirectly carry, in corresponding angular positions about the axis that is defined by the pivots 7. It will be appreciated that, when the bolts 23A are temporarily removed, rotation of the sleeve 25 about its own longitudinal axis in one direction or the other will cause the arms 8, carriers 9 and the bridge arm 23 to be turned either upwardly or downwardly about the axis that is defined by the pivots 7. If a greater degree of adjustability is required than is available by employing the holes 23B, said holes may be replaced by arcuately curved slots through which are entered clamping bolts equivalent to the bolts 23A.

Infinitely variable adjustability of the arms 8 about the axis defined by the pivots 7 is then available within the limits that are dictated by the opposite ends of the arcuately curved slots.

Figures 3 and 4 of the drawings illustrate an alternative form of soil cultivating implement in accordance with the invention in which substantially rectilinear strip-shaped carrier arms 26A replace the arms 8, carriers 9 and arms 9B, the rearmost ends of the two carrier arms 26A with respect to the direction A being perpendicularly interconnected by a transverse strip-shaped beam 27A that is parallel or substantially parallel to the transverse length of the hollow frame portion 1. In this embodiment, a larger diameter leading compacting roller 26 is provided followed, in the direction A, by a smaller diameter soil crumbling roller 28. As in the case of the first embodiment, the leading compacting roller 26 is located immediately to the rear of the soil working members 3 with respect to the direction A, its axis of free rotatability being afforded by a central shaft 28B that substantially horizontally inter-connects the two carrier arms 26A at the locations ofjunctions between two marginally inclined portions of each of the two arms 26A (see Figure 4). The compacting roller 26 is afforded by a large number of seperate, individually freely rotatable, soil consolidating members in the form of discs 27. Each disc 27 is formed principally from sheet metal or other sheet material and has a central spacing hub 28A by which it is rotatably mounted on the shaft 28B, the successive hubs 28A ensuring that the discs 27 remain in substantially fixed positions as regards their locations along the length of the shaft 28B. The edge of each disc 27 has a central flange and may therefore be considered to be substantially V-shaped as seen in cross-section. This is also true of the discs 13 of the roller 11 of Figure 1 and 2 of the drawings.

The smaller diameter soil crumbling roller 28 is rotatable about the axis of a central shaft 29A that inter-connects the carrier arms 26A at locations towards the rearmost ends of those arms, the longitudinal axis of the shaft 29A being in parallel relationship with that of the shaft 28B and the transverse length of the hollow frame portion 1. The roller 28, like the roller 26, is afforded by a large number of discs 29 but it will be seen from Figure 4 of the drawings that the central flange of each disc 29 has a sawtoothed or other serrated edge in contradistinction to the smooth uninterrupted edge of the flange of each disc 27. Each disc 29 is rotatable about the axis of the shaft 29A independently spacing hub 29B, the arrangement being such that said hubs 29B maintain the discs 29 in substantially fixed positions as regards their locations axially along the shaft 29A. The discs 29 of the smaller diameter roller 28 constitute scraping members and it will be clear from Figures 3 and 4 of the drawings that the two rollers 26 and 28 are arranged in overlapping relationship with the discs 27 extending into the spaces between the successive discs 29 and vice versa.

Support arms 30A project obliquely upwardly and rearwardly from the two carrier arms 26A at substantially the locations on those arms to which the opposite ends of the shaft 28B are secured, the upper rear ends of the support arms 30A being interconnected by a beam of L-shaped cross-section which beam carries a scraper blade 30B that is disposed for co-operation with the free edges of the flanges of the discs 27 when the roller 26 is in operative rotation. The beam of Lshaped cross-section that supports the scraper blade 30B is provided at a location substantially midway along its length with a pair of upwardly and forwardly inclined lugs 31A whose free ends are pivotally connected to the limbs of the previously described fork 24A by aligned pivot pins 3 1B which are equivalent to the previously described pivot pins 22.

Figure 5 of the drawings illustrates an alternative embodiment in which the central shaft 28B of the leading compacting roller 26 is rotatably mounted and has the discs 27 fixedly secured to it. Similarly, the central shaft 29A of the smaller diameter soil crumbling roller 28 is rotatably mounted and has the corresponding scraping discs 29 fixedly secured to it. The shafts 28B and 29A have ends that project through one of the carrier arms 26A and those ends are provided with larger and smaller sprocket wheels 31 and 33, respectively. An endless transmission chain 32 drivingly inter-connects the sprocket wheels 31 and 33 and the parts 31, 32 and 33 are contained within a protective casing 35 that is fastened to the adjacent carrier arm 26A.

In the use of the soil cultivating implement that has been described, its coupling member or trestle 20 is connected to the three-point lifting device or hitch at the rear of an agricultural tractor or other operating vehicle and the leading forwardly projecting end of the shaft 18 is placed in driven connection with the power take-off shaft at the rear of the same tractor or other vehicle by way of the known telescopic transmission shaft 19 that has universal joints at its opposite ends.

Adjustments that may, if necessary, be made before work commences including increasing or decreasing the speed of rotation of the soil working members 3 in response to a substan tially constant input speed of rotation ap plied to the shaft 18 by selecting an appropri ate transmission ratio in the change-speed gear 17A as briefly described above and increasing or decreasing the maximum depth to which the tines 5 of the soil working members 3 can penetrate into the ground by temporarily withdrawing the bolts or like fastenings 23A, rotating the sleeve 25 and replacing and retightening the bolts 23A when the holes in the arms 8 or 26A register with fresh holes 23B. It will be appreciated that this pivotal adjustment bodily changes the level of the rollers 11 and 14 or 26 and 28, in common, relative to the level of the frame portion 1 and thus controls the maximum extent of penetration of the tines 5 into the ground which is possible. The adjustments which have just been mentioned will usually be made in the light of the nature and condition of the soil that is to be cultivated and the particular purpose for which that soil is required after treatment. As the implement is moved operatively in the direction A by the agricultural tractor or other vehicle to which it is connected, the soil working members 3 revolve in the directions that are indicated by small arrows in Figures 1 and 3 of the drawings which directions are, it will be noted, such that each member 3 rotates in .the opposite sense to its immediate neigh bour, or both of its immediate neighbours, in the row of twelve members 3. The spacing between the two tines 5 of each member 3 is a little greater than is the distance between the axes of rotation of immediately neighbouring members 3 so that the strips of ground that are worked by the members 3 overlap one another to a small extent thus producing, in effect, a single broad strip of worked soil which will have a width of substantially 3 metres in the case of an implement having twelve of the members 3 with the dimensions that have been referred to above. The broad strip of soil that is worked by the row of twelve members 3 is consolidated by the immediately following compacting roller 11 in the embodiment of Figures 1 and 2 of the drawings and this consolidation tends to produce a significant increase in the success ful germination rate of seeds that are subse quently sown in the cultivated soil, this increase in the successful germination rate of subsequently sown seeds being particularly marked when the soil concerned is light soil which is usually of a somewhat dry and well draining nature. The second smaller diame ter roller 14 that is provided in the embodi ment of Figures 1 and 2 of the drawings at least partially obliterates the lines and other marks that are made in the surface of the soil by the flanges of the discs 13 that afford the roller 11, the roller 14 also acting to crush any unbroken lumps of soil that may have been left on the surface by the foregoing soil working members 3 and compacting roller 11. Due to its somewhat small diameter, the roller 14 will perform its obliterating and crumbling action efficiently even when the speed of operative travel of the implement in the direction A is very low.

When somewhat heavier soil is to be cultivated, it is preferable, although not essential, to employ the construction that has been described with reference to Figures 3 and 4 of the drawings in preference to the embodiment of Figures 1 and 2. There is a considerably increased tendency for heavier soils to adhere to the leading compacting roller 26 but such adhension is effectively prevented, or is reduced to such an extent that the compacting action of the roller 26 is not interfered with, by the co-operating smaller diameter roller 28 which roller 28, like the roller 14, also acts to crush any lumps of soil that may have been left lying upon the surface by the foregoing members 3 and compacting roller 26.

When still heavier soils in a sticky condition are to be dealt with, it is desirable to employ the embodiment that has been described with reference to Figure 5 of the drawings since the second smaller diameter soil crumbling roller 28 then has a considerably enhanced scraping effect upon the discs 27 of the leading compacting roller 26. In the embodiment of Figure 5 of the drawings, the second smaller diameter roller 28 is driven from the leading compacting roller 26 by way of the transmission chain 32, the pinions 31 and 33 being of such sizes that the circumferential speed of rotation of the smaller roller 28 is greater than that of the larger roller 26. The drive transmission between the rollers 26 and 28 ensures that the scraping effect of the discs 29 upon the discs 27 is considerably intensified, the crumbling action of the roller 28 also being increased as compared with the embodiment of Figures 3 and 4 of the drawings. It is noted that, in the embodiments of Figures 3 to 5 of the drawings, the scraper blade 30B also cooperates with the smaller diameter soil crumbling roller 28 in preventing the leading larger diameter compacting roller 26 from becoming blocked by adhering soil to an extent which would significantly interfere with its compacting effect.

WHAT WE CLAIM IS: 1. A soil cultivating implement of the kind set forth, wherein two ground rollers are provided whose intended axes of rotation are disposed one behind the other in said direction at locations to the rear of said row of the soil working members, said two rollers being of different effective diameters and both of them being bodily pivotable, in common, relative to a frame portion of the implement

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

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. working members 3 in response to a substan tially constant input speed of rotation ap plied to the shaft 18 by selecting an appropri ate transmission ratio in the change-speed gear 17A as briefly described above and increasing or decreasing the maximum depth to which the tines 5 of the soil working members 3 can penetrate into the ground by temporarily withdrawing the bolts or like fastenings 23A, rotating the sleeve 25 and replacing and retightening the bolts 23A when the holes in the arms 8 or 26A register with fresh holes 23B. It will be appreciated that this pivotal adjustment bodily changes the level of the rollers 11 and 14 or 26 and 28, in common, relative to the level of the frame portion 1 and thus controls the maximum extent of penetration of the tines 5 into the ground which is possible. The adjustments which have just been mentioned will usually be made in the light of the nature and condition of the soil that is to be cultivated and the particular purpose for which that soil is required after treatment. As the implement is moved operatively in the direction A by the agricultural tractor or other vehicle to which it is connected, the soil working members 3 revolve in the directions that are indicated by small arrows in Figures 1 and 3 of the drawings which directions are, it will be noted, such that each member 3 rotates in .the opposite sense to its immediate neigh bour, or both of its immediate neighbours, in the row of twelve members 3. The spacing between the two tines 5 of each member 3 is a little greater than is the distance between the axes of rotation of immediately neighbouring members 3 so that the strips of ground that are worked by the members 3 overlap one another to a small extent thus producing, in effect, a single broad strip of worked soil which will have a width of substantially 3 metres in the case of an implement having twelve of the members 3 with the dimensions that have been referred to above. The broad strip of soil that is worked by the row of twelve members 3 is consolidated by the immediately following compacting roller 11 in the embodiment of Figures 1 and 2 of the drawings and this consolidation tends to produce a significant increase in the success ful germination rate of seeds that are subse quently sown in the cultivated soil, this increase in the successful germination rate of subsequently sown seeds being particularly marked when the soil concerned is light soil which is usually of a somewhat dry and well draining nature. The second smaller diame ter roller 14 that is provided in the embodi ment of Figures 1 and 2 of the drawings at least partially obliterates the lines and other marks that are made in the surface of the soil by the flanges of the discs 13 that afford the roller 11, the roller 14 also acting to crush any unbroken lumps of soil that may have been left on the surface by the foregoing soil working members 3 and compacting roller 11. Due to its somewhat small diameter, the roller 14 will perform its obliterating and crumbling action efficiently even when the speed of operative travel of the implement in the direction A is very low. When somewhat heavier soil is to be cultivated, it is preferable, although not essential, to employ the construction that has been described with reference to Figures 3 and 4 of the drawings in preference to the embodiment of Figures 1 and 2. There is a considerably increased tendency for heavier soils to adhere to the leading compacting roller 26 but such adhension is effectively prevented, or is reduced to such an extent that the compacting action of the roller 26 is not interfered with, by the co-operating smaller diameter roller 28 which roller 28, like the roller 14, also acts to crush any lumps of soil that may have been left lying upon the surface by the foregoing members 3 and compacting roller 26. When still heavier soils in a sticky condition are to be dealt with, it is desirable to employ the embodiment that has been described with reference to Figure 5 of the drawings since the second smaller diameter soil crumbling roller 28 then has a considerably enhanced scraping effect upon the discs 27 of the leading compacting roller 26. In the embodiment of Figure 5 of the drawings, the second smaller diameter roller 28 is driven from the leading compacting roller 26 by way of the transmission chain 32, the pinions 31 and 33 being of such sizes that the circumferential speed of rotation of the smaller roller 28 is greater than that of the larger roller 26. The drive transmission between the rollers 26 and 28 ensures that the scraping effect of the discs 29 upon the discs 27 is considerably intensified, the crumbling action of the roller 28 also being increased as compared with the embodiment of Figures 3 and 4 of the drawings. It is noted that, in the embodiments of Figures 3 to 5 of the drawings, the scraper blade 30B also cooperates with the smaller diameter soil crumbling roller 28 in preventing the leading larger diameter compacting roller 26 from becoming blocked by adhering soil to an extent which would significantly interfere with its compacting effect. WHAT WE CLAIM IS:

1. A soil cultivating implement of the kind set forth, wherein two ground rollers are provided whose intended axes of rotation are disposed one behind the other in said direction at locations to the rear of said row of the soil working members, said two rollers being of different effective diameters and both of them being bodily pivotable, in common, relative to a frame portion of the implement

by the displacement of carriers to which the rollers are connected.

2. An implement as claimed in claim 1, wherein the larger diameter roller is located immediately to the rear of said row of the soil working members with respect to the intended direction of operative travel of the implement.

3. An implement as claimed in claim 1 or 2, wherein the effective diameter of the larger of said two rollers is substantially twice that of the smaller roller.

4. An implement as claimed in any preceding claim, wherein the larger diameter roller is constructed and arranged to act as a soil compacting roller.

5. An implement as claimed in any preceding claim, wherein the smaller diameter roller is constructed and arranged to act as a soil crumbling roller.

6. An implement as claimed in any preceding claim, wherein said two rollers are spaced apart from one another by a distance which is equal to substantially half the effective diameter of the smaller roller.

7. An implement as claimed in any preceding claim, wherein said carriers are pivotally arranged in such a way as to enable the two rollers to be bodily displaced, in common, upwardly or downwardly relative to said frame portion.

8. An implement as claimed in any preceding claim, wherein an adjusting mechanism that is located substantially midway across the width of the implement is provided for bodily pivoting the two rollers, in common, relative to said frame portion.

9. An implement as claimed in any preceding claim, wherein the smaller diameter roller comprises circumferentially mounted elongate elements that are formed or provided with outwardly directed serrations.

10. An implement as claimed in claim 9, wherein said elements extend helically around the intended axis of rotation of the smaller diameter roller.

11. An implement as claimed in any one of claims 1 to 5, wherein the smaller diameter roller comprises a plurality of scraping members arranged in side-by-side relationship, the smaller diameter roller occupying such a position relative to the larger diameter roller that, during operation of the implement, said scraping members overlap, and move between, a plurality of soil consolidating members of the larger diameter roller.

12. An implement as claimed in claim 11, wherein the scraping members are in the form of discs that are formed, or provided, with circumferential serrations.

13. An implement as claimed in any preceding claim, wherein said two rollers are interconnected by a drive transmission.

14. An implement as claimed in claim 13, wherein the drive transmission is constructed and arranged in such a way that, during the operation of the implement, the smaller diameter roller will rotate more rapidly than the larger diameter roller.

15. An implement as claimed in claim 13 or 14, wherein said drive transmission is located alongside one axial end of each roller.

16. A soil cultivating implement ofthe kind set forth, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings or with reler- ence to Figures 1 and 2 as modified by Figures 3 and 4 or as modified by Figures 3, 4 and 5 of the accompanying drawings.