GB2153192A - A soil cultivating implement with a ground contacting roller assembly - Google Patents

Abstract

In a soil cultivating implement comprising a plurality of power- drivable soil working members having rigid tines 5 or other soil working tools, the implement is sustained from the ground surface by a roller assembly 16 which assembly is vertically displaceable relative to that of the remainder of the implement to govern the maximum depth of penetration of said soil working tools into the ground and which performs a further crumbling action upon the soil already worked by said tools and to distribute that soil as uniformly as possible throughout the working width of the implement. The roller assembly 16 comprises two parallel rollers, which may be driven, that are located one behind the other in the intended direction of operative travel A of the implement, each roller having a central tubular part in the form of a sleeve 15 which bears against the ground surface during operation. Each sleeve 15 carries a plurality of groups of teeth 17 that are of hollow formation, each tooth being formed by the interconnection of rimmed pairs of substantially symmetrically identical plates 18. <IMAGE>

Description

SPECIFICATION Ground rollers This invention relates to ground roller assemblies in soil cultivating implements or machines, the term "implement(s)" alone being substituted for "implement(s) or machine(s)" throughout the remainder of this document for the sake of brevity.

At least one ground roller often forms a part of many known soil cultivating implements and is required to sustain the implement from the ground surface, to govern the maximum depth of penetration of soil working tools of the implement into the ground surface which is possible, and to crumble still further the soil worked by those tools whilst simultaneously distributing the crumbled soil as uniformly as possible throughout the working width of the implement and/or gently compressing that worked soil. To achieve this combination of operational requirements, the roller must have high rigidity, must contact the ground over a relatively large area and must be designed so that it will produce both further soil crumbling and lateral spreading of that soil.

The ground rollers of known soil cultivating implements are usually constructed to give a result which is a compromise between the requirements discussed above and, often, at least one of their functions is performed to a less than really satisfactory extent.

An object of the present invention is to provide a ground roller assembly in an implement of this kind which assembly will meet the requirements referred to previously to a significantly improved extent. According to one aspect of the invention, there is provided a ground roller assembly in a soil cultivating implement, wherein that assembly comprises two rollers located substantially one behind the other in the intended direction of operative travel of the implement with at least one of those rollers having a central tubular part which bears upon the ground surface in the use of the implement.

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 comprising a roller assembly in accordance with the invention, the implement being shown connected to the rear of an agricultural tractor, Figure 2 is a side elevation as seen in the direction indicated by an arrow II, Figure 3 is an incomplete section, to an enlarged scale, taken on the line Ill-Ill in Figure 1, Figure 4 is a plan view as seen in the direction indicated by a arrow IV in Figure 3, Figure 5 corresponds to Fig.1 but illustrates an alternative roller assembly and means by which that assembly may be mechanically driven, Figure 6 is a side elevation as seen in the direction indicated by an arrow VI in Figure 5, and Figure 7 is an incomplete section, to an enlarged scale, taken on the line VII-VII in Fig.5.

Referring to the accompanying drawings, and initially to Figs. 1 to 4 thereof, the soil cultivating implement that is illustrated includes a roller assembly 1 6 that will be described in detail below, the implement being in the form of a rotary harrow that is intended primarily, but not exclusively, for the preparation of seed beds in previously cultivated soil.

The implement has a hollow box-section frame portion 1 that is of elongate configuration, its longitudinal axis extending substantially horizontally transverse and usually, as illustrated, substantially horizontally perpendicular, to the intended direction of operative travel of the implement that is indicated in Figs. 1 ,2, 5 and 6 of the drawings by an arrow A. A plurality, of which there are twelve in the example that is being described, of substantially vertical, or at least upwardly extending, shafts 2 are rotatably journalled in bearings carried by upper and lower walls of the frame portion 1 so as to be power-rotatable about their individual longitudinal axes which relatively parallel axes are advantageously, but not essentially, spaced apart from one another at regular intervals having magnitudes of substantially 25 cms.

A lower end portion of each shaft 2 projects downwardly from beneath the bottom of the hollow frame portion 1 and is there provided with a corresponding rotary soil working member that is generally indicated by the reference 3 (Fig.2). Each rotary soil working member 3 comprises a substantially horizontal carrier 4 having two substantially symmetrically identical arms which radiate from a central hub of the carrier 4 that is firmly but releaseably secured to the splined or otherwise keyed downwardly projecting portion of the corresponding shaft 2 by means which includes a washer and a nut co-operating with a short lowermost screw-threaded part, the nut preferably being provided with known means that will prevent it from working loose when the implement is in operation.The outer ends of the two arms of each carrier 4 are integrally or rigidly provided with corresponding sleeve-like holders in which upper fastening portions of soil working tools in the form of rigid metallic tines 5 are firmly but releaseably secured by means which includes a nut (see Fig.2) co-operating with a short screwthreaded uppermost part of the fastening portion concerned, this part projecting a short distance above a mouth at the upper end of the sleeve-like holder in question.

The opposite ends of the hollow frame portion 1 are closed by corresponding side plates 6 which are disposed substantially vertically parallel to one another and to the direction A, it being evident from Fig.2 of the drawings that each of the symmetrically identical side plates 6 has a much larger area than does the end of the frame portion 1 to which it is secured, each side plate 6, in particular, being extended upwardly by a significant distance above the substantially flat top of the frame portion 1.The two side plates 6 are provided, close to their upper leading corners, with respect to the direction A, with substantially horizontally aligned strong pivots 7 and each pivot 7 has the leading end of a corresponding arm 8 mounted thereon at the side of the respective plate 6 which faces the centre of the implement, each arm 8 extending generally rearwardly from its pivot 7 to a location well behind the frame portion 1. Each arm 8 includes a straight leading portion 9 which, although not shown as being horizontally disposed in Fig.2 of the drawings, may be considered as extending substantially horizontally rearwards from the corresponding pivot 7, the precise angular disposition of the portion 9 depending upon the setting of the corresponding arm 8 about that pivot 7.The rearmost end of each leading arm portion 9 is rigidly secured to the leading and upper end of a corresponding rear portion 10 of straight configuration that is inclined quite steeply downwardly and rearwardly from the leading portion 9 concerned to its free end. It will be seen from Fig. 2 of the drawings that the rigid junction between the two portions 9 and 10 of each arm 8 is located well to the rear of the hollow frame portion 1 with respect to the direction A.

Adjustment means that is generally indicated by the reference 1 OA is provided to enable a chosen angular setting of each arm 8 about the axis defined by the aligned strong pivots 7 to be determined. The adjustment means 1 0A may, as illustrated, be of a kind which is generally known per se, each of them comprising a spindle having a manually rotatable crank handle at its upper end, the spindle being screw-threaded throughout the greater part of its length and the lowermost end thereof, which is not screw-threaded, being connected to a lug which projects rearwardly from the frame portion 1, adjacent the neighbouring end thereof, so as to be rotatable relative to that lug without significant axial displacement but with the facility to move the longitudinal axis of the spindle angularly to some extent about its connection to the lug.

The major portion of the shank of the spindle, which is screw-threaded, is entered through a matchingly internally screw-threaded bore formed transversely through a block that is mounted on the leading portion 9 of the neighbouring arm 8 so as to be turnable relative to that arm portion 9 about a substantially horizontal axis that is substantially parallel to the axis defined by the pivots 7, the blocks being disposed nearer to the junctions between the portions 9 and 10 of the arms 8 than they are to the corresponding pivots 7.It will readily be apparent that, upon manually rotating the spindle of either mechanism 1 or, the corresponding arm 8 will be turned upwardly or downwardly, depending upon the direction of such rotation, about the axis defined by the pivots 7, this adjustment being infinitely variable between the limits set by the opposite ends of the screw-threaded portion of the shank of the spindle concerned. If considered necessary, means which is not shown in the drawings may be provided to clamp each arm 8 firmly but releaseably to the immediately neighbouring frame portion side plate 6 in order to relieve the adjustment mechanism 1 0A of the stresses to which it would otherwise be subject during operative progress in the direction A.

Two pivots 11 which will normally be substantially horizontally aligned in a direction parallel to the single row of rotary soil working members 3 are mounted at substantially the lowermost and rearmost ends of the two arm portions 10 and have corresponding substantially symmetrically identical carriers 1 2 turnably mounted on them so that the two carriers 1 2 will normally extend substantially horizontally parallel to one another and to the direction A, projecting forwardly and rearwardly from the pivots 11 by equal distances.

The forwardly and rearwardly projecting portions of the two carriers 1 2 are each provided with a corresponding housing 1 3 for a corresponding substantially horizontal bearing and it will be apparent from the drawings that, normally, the two leading bearings that correspond to the leading portions of the two carriers 1 2 will be substantially horizontally aligned in parallel relationship with the axis defined by the pivots 11 as will also be the two bearings that correspond to the rear portions of the two carriers 1 2. Each pair of bearings which corresponds to a transversely aligned pair of bearing housings 1 3 receives substantially horizontal stub shafts 1 4 at the opposite ends of a respective roller of the aforementioned roller assembly 16, each roller being individually designated "16" in the drawings for the sake of convenience. The stub shafts 14 are secured to plates (not visible) at the opposite ends of a tubular sleeve 1 5 forming a central axially extending part of the roller 1 6 concerned.

The two rollers, their carriers 1 2 and the arms 8 afford the roller assembly 1 6 in the example that is being described with reference to Figs. 1 to 4 of the drawings, the roller assembly 1 6 bearing upon the ground surface in such a way that said surface principally supports the two tubular sleeves 1 5 and thus governs to a large extent the maximum depth to which the tines 5 of the soil working members 3 can penetrate into the soil when the implement is in use since it is the bodily level of the roller assembly 1 6 relative to that of the frame portion 1 and soil working members 3 which is the primary factor in determining the horizontal level of the frame portion 1 and members 3 as the implement moves operatively in the direction A.As previously discussed, the adjustment mechanism 1 0A can be employed to change this setting if and when required. In addition, soil which has previously been worked by the immediately foregoing members 3 is engaged by the two rollers of the assembly 1 6 which rollers perform a further crumbling action upon that soil with crushing of any stubborn lumps of soil not dealt with by the rotary members 3, the two rollers of the assembly 1 6 furthermore assisting in distributing the worked soil substantially uniformly throughout the combined working width of the twelve (in this embodiment) soil working members 3.

Each tubular sleeve 1 5 is preferably, as illustrated, of circular cross-section but this is not essential and a polygonal cross-section could, if desired, be used as an alternative for either both or only one of the two rollers of the assembly 16. In the example that is being described, each circular cross-section tubular sleeve 1 5 has an external diameter of substantially 1 5 cms. and the sleeves 1 5 of the two rollers are spaced apart from one another in the direction A by a distance which is such that the minimum surface-to-surface measurement is at least substantially equal to the external diameter of one of them (see Figs. 3 and 4 of the drawings).

The tubular sleeve 1 5 of each roller 1 6 carries a large number of teeth or tines 1 7 that will hereinafter be referred to as teeth alone for the sake of brevity. As can be seen clearly in both Figs. 1 and 4 of the drawings, the teeth 1 7 are secured to the external surface of the corresponding sleeve 1 5 in groups of three which groups are spaced apart from one another along the sleeve concerned by a distance which is preferably substantially equal to the external radius of one of the sleeves 1 5. The groups of teeth 1 7 are spaced apart from one another by the same distances on both of the rollers 1 6 and the general plane of each group is substantially vertically perpendicular to the longitudinal axis/axis of rotation a of the corresponding roller 1 6 and thus parallel or substantially parallel to the direction A, the groups of teeth 1 7 on the two rollers 1 6 being so arranged that, except at one end of each roller, the general plane of any selected group of teeth 1 7 of one roller 1 6 is substantially exactly mid-way between the general planes of two groups of teeth 1 7 on the other roller 1 6. It will be apparent from Fig. 3 of the drawings that the radial projection of each tooth 1 7 from the respective tubular sleeve 1 5 is nearly, but not quite, equal to the magnitude of the closest approach between the outer surfaces of the two sleeves 1 5 as measured in the direction A.

Thus, during operation, the outer end of each tooth 1 7 repeatedly passes very close to the external surface of the sleeve 1 5 of the other roller 1 6. The three tines 17 of each group are spaced apart from one another at 120 intervals around the corresponding axis a and, when the corresponding sleeve 1 5 is of polygonal, rather than circular, cross-section, the spacing of the groups of teeth 1 7 lengthwise along the roller 1 6 concerned is advantageously equal to the radius of an imaginary circle circumscribing the cross-section of the polygon in question.In the example that is being described, each group of teeth 1 7 occupies the same angular position about the respective axis a as does every other group on the same roller 1 6 but this is not essential and, if preferred, each group may be turned about the axis a concerned by the same angle relative to the or each of its neighbours so that, in the finished roller, the teeth 1 7 will extend in three helical rows around the tubular sleeve 1 5 in question.

Each of the teeth 1 7 is formed from two plates 1 8 that are substantially symmetrically identical to one another relative to an imaginary substantially vertical plane that is perpendicular to the axis of rotation a concerned.

Each pair of plates 1 8 has perpendicularly bent-over rims that are firmly secured to one another, preferably by welding. The inner or root end of each tooth 1 7 is curved to match the curvature of the outer surface of the sleeve 1 5 to which it is secured and said tooth has a curved rear edge with respect to the intended direction of operative rotation B (Figs. 2 and 3) of the roller 1 6 concerned. As can be seen best in Fig.3, each tooth subtends an angle of marginally less than 120 at the corresponding axis a and its radially outermost end is curved so as to lie substantially on an imaginary circle (shown in Fig.3) centered upon said axis a.This curved outer end, as shown in Fig.3, subtends an angle of substantially 30 at the axis a and forms part of a substantially planar rim 1 9 that is produced by securing tongue-like parts of the corresponding pair of plates 1 8 to one another in surface-to-surface relationship.

Each rim 1 9 extends forwardly (with respect to the corresponding direction B) along the outer end of the tooth 1 7 concerned, from the rearmost extremity of that end, and is prolonged by way of a fairly sharp substantially 90= bend into the leading straight edge of the same tooth 1 7, again with respect to the direction B concerned.The leading edge of each tooth rim 1 9 that has just been mentioned is not radially disposed with respect to the corresponding axis a but is inclined to an imaginary radial line by an angle a having a magnitude that is preferably not less than 10 and not more than 15=. The leading straight edge of each tooth rim 1 9 terminates at the external surface of the corresponding tubular sleeve 15.

The opposite or trailing edge of each tooth 17, with respect to the direction B concerned, does not exhibit the rim 1 9 and is smoothly curved outwardly and forwardly (with respect to the direction B) from the external surface of the sleeve 1 5 to the rearmost extremity of the outer end of the tooth 1 7 concerned, the curve under consideration extending into the rim 1 9 only where that rim 1 9 coincides with the outer end of the tooth.As seen in Fig.3, a chord K interconnecting the outer surface of the tubular sleeve 1 5 under consideration and the radially outer end of the rear curved edge of one of the teeth 1 7 is inclined to a line extending radially from the axis a to the lastmentioned end of that rear curved edge by an angle ss which preferably is not less than 20 nor more than 30', a magnitude of substantially 25 being preferred.

The three teeth 1 7 of each group are, as can be seen in Fig.3 of the drawings, identically arranged one after the other considered rotationally around the corresponding axis a.

Thus, the leading straight edge of each tooth 17, relative to the corresponding direction B, exhibits the rim 1 9 and is therefore a "sharp" edge whereas the rear curved edge thereof, with respect to the same direction, does not exhibit the rim 19, except effectively at its outer end, and is therefore a relatively "blunt" edge since the flat sides of the two plates 18 of each tooth 1 7 are in parallel but relatively spaced apart relationship with one another except where they are bent over for relative interconnection and except where the rims 19 are formed. Thus, each tooth 1 7 is internally hollow.

Each shaft 2 is provided, inside the hollow frame portion 1, with a corresponding straight- or spur-toothed pinion 20, the twelve pinions 20, in this embodiment, being of such a size that the teeth of each of them are in mesh with those of the or each neighbouring pinion 20 in the single row thereof. One of the centre pair of twelve shafts 2 in the single row of twelve shafts has an upward extension through the top of the hollow frame portion 1 into a gear box 21 that is firmly but releaseably bolted in position, or otherwise mounted, on top of said frame portion 1.The gear box 21 includes a rotary input shaft 23 whose splined or otherwise keyed end projects substantially horizontally forwards from the front of that gear box in substantially the direction A where it can be placed, as illustrated, in driven connection with the rear power take-off shaft of a tractor or other operating vehicle by way of an intermediate telescopic transmission shaft 24, which is of a construction that is known per se, having universal joints at its opposite ends. Shafts and bevel pinions within the gear box 21 place the rotary input shaft 23 in driving connection with the upward extension of said one of the shafts 2 that has been mentioned above and the back of the gear box 21, with respect to the direction A. is provided with a change-speed gear 22 whose construction is not the subject of the present invention.It suffices to say that the change-speed gear 22 has a readily removable cover beneath which the splined or otherwise keyed ends of two shafts are accessible to co-operate with the matchingly internally splined or otherwise keyed hubs of two straight- or spur-toothed pinions whose sizes are such that their teeth will mesh with one another and dictate a corresponding transmission ratio between the two shafts concerned. The two pinions can be interchanged on the shaft ends or can be exchanged for at least one other pair of cooperating pinions of different relative sizes so that any chosen one of a number of different transmission ratios is available enabling the soil working members 3 to be rotated at faster or slower rates without having to alter the driving speed of rotation which is applied to the leading end of the rotary input shaft 23.

The top and front of the hollow frame portion 1, with respect to the direction A, are provided with a coupling member or trestle 25 which exhibits coupling points arranged to enable the implement to be connected to the three-point lifting device or hitch at the rear of the same agricultural tractor or other vehicle that is both to move the implement in the direction A and to operate the same. The construction and arrangement of the coupling member or trestle 25 may be known per se and are illustrated somewhat diagrammatically in Figs. 1 and 2 of the drawings.

When the implement is to be used in performing a cultivating operation with a view to.

for example, producing a seed bed, the coupling member or trestle 25 is connected to the three-point lifting device or hitch of the tractor which is both to move and operate it and adjustments that may, if necessary, be made before work commences include operating the mechanism 1 0A to change the maximum depth of penetration of the rigid tines 5 into the soil which is possible and/or altering the transmission ratio in the change-speed gear 22 to cause the soil working members 3 to revolve at a faster or slower speed. These adjustments will usually be made in the light of the nature and condition of the soil that is to be dealt with and the particular purpose for which that soil is required after its cultivation.

As the implement is moved operatively in the direction A over land that is to be cultivated, each pinion 20, shaft 2 and soil working member 3 will be revolved in the opposite direction to the or each immediately neigh bouring assembly due to the inter-meshing relationship of neighbouring pinions 20, this direction of rotation being indicated for two such immediately neighbouring assemblies by small arrows at the foot of Fig. 1 of the drawings.Each soil working member 3 produces a corresponding strip of worked soil that extends in the direction A but, since those members 3 are so constructed and arranged that the width of each such individual strip of land is the same as, or marginally greater than, the spacing between neighbouring axes of rotation of the soil working members 3, the twelve, in this embodiment, strips will overlap, or at least adjoin, one another to form a single broad strip of worked soil extending in the direction A. When the preferred dimensions referred to above are employed, this broad strip of work soil will have a width of substantially, but not necessarily exactly, three metres. It will be evident that larger or smaller working widths could be produced by increasing or decreasing the number of rotary soil working members 3.

In addition to supporting the implement from the ground surface during its operative progress in the direction A, the freely rotatable rollers 1 6 themselves work the soil, particularly dealing with any lumps thereof exceptionally missed by the members 3 and producing a substantially uniform distribution of the worked soil throughout the combined working width of the members 3 and the similar and substantially coinciding working width of the roller assembly 1 6. The two rollers 1 6 sustain the implement from the ground surface primarily by the engagement of the outer surfaces of their tubular sleeves 1 5 with that ground surface, the sleeves 15, as previously mentioned, preferably being of circular crosssection and each roller 1 6 advantageously having a diameter (including its teeth 17) of substantially 35 cms.

Those curved and relatively blunt edges of the teeth 1 7 which are rearmost with respect to the directions of rotation B, meet relatively high resistance to displacement of the soil and this resistance, in fact, produces that rotation in the directions B as the implement moves forwardly in the direction A.As the leading edges, with respect to the directions B, of the teeth 1 7 are of relatively sharp formation, due to the provision of the rims 19, they tend, together with the outer ends of those teeth 17, to cut into the soil so that said teeth 1 7 will normally penetrate into the ground until its surface is substantially flush with the lowermost locations on the outer surfaces of the two sleeves 1 5. This cutting effect is improved by the fact that the leading rimmed edge of each tooth 17, with respect to the corresponding direction B, trails outwardly and rearwardly relative to the same direction from the sleeve 1 5 concerned to its curved junction with the outer end of the tooth at the aforementioned angle (Fig.3) as compared with a truly radial line.The curved relatively blunt and opposite relatively sharp edges of each tooth 1 7 facilitate rapid penetration of that tooth into the ground until the outer surface of the respective tubular sleeve 1 5 comes into contact with the ground surface and, due to the resistance of the penetrated soil to the passage of the curved relatively blunt edge therethrough, substantially uninterrupted rotation of each roller 1 6 about the corresponding axis a is ensured at a substantially uniform rate which is, of course, proportional to the rate of travel in the direction A.

Since the teeth 1 7 on one roller 1 6 move between the teeth 1 7 on the other roller 16, any significant accumulation of jammed soil and/or of some other agricultural debris will not take place between the teeth 1 7 of neighbouring groups since such momentarily jammed soil and/or agricultural debris is rapidly pushed away from its jammed position by the teeth 1 7 of the other roller 16.

Figs. 5 to 7 of the drawings illustrates a second embodiment of a soil cultivating implement having a roller assembly 1 6 constructed in accordance with the invention.

Many parts that are similar, of identical, to parts which have already been described above with reference to Figs. 1 to 4 of the drawings are indicated in Figs. 5 to 7 of those drawings by the same reference numerals as in the preceding Figures and will not be described in detail again.

In this embodiment, the two rollers 1 6 are supported, at their opposite ends, by corresponding carriers 29, the irregular substantially hexagonal shape of one of which is clearly illustrated in Fig. 6 of the drawings.

Each carrier 29 is connected by pivotally mounted upper and lower links 26 and 27 to a leading region of an upwardly extending frame portion side plate 28 that, apart from its shape, substantially corresponds to one of the previously described side plates 6. The pivots by which the links 26 and 27 are coupled to the side plates 28 and carriers 29 all extend substantially horizontally parallel to the single row of rotary soil working members 3 and, as seen in Fig. 6, are at the four corners of a pivotable quadrilateral linkage that, in the embodiment which is being described, is a parallelogram linkage.

Each substantially hexagonal carrier 29 has a shorter substantially horizontal upper edge and a longer relatively parallel and substantially horizontal lower edge, a substantially vertical straight leading edge whose lower end is connected to the leading end of the lower substantially horizontal edge by a downwardly and rearwardly inclined edge and also two relatively inclined rear edge portions the shorter and lower straight portion of which is upwardly and rearwardly inclined from the rear end of the lower edge and the longer straight portion of which is upwardly and forwardly inclined from the upper end of the edge portion that has just been mentioned to the rear end of the upper horizontal edge of the carrier 29.The straight upper rear edge portion is parallel or substantially parallel to the straight edge which obliquely interconnects the lower end of the substantially vertical leading edge and the leading end of the substantially horizontal lower edge. The junction between the lower end of the substantially vertical straight leading edge and the upper end of the upwardly and forwardly inclined leading edge and the junction between the two relatively inclined portions of the rear edge are at substantially the same horizontal level.

The two rollers of the roller assembly 1 6 of this embodiment have substantially exactly the same constructions as those of the first embodiment but each of them is rotatably mounted about the corresponding axis a in a position in which it is turned through 180 end-for-end as compared with the two rollers in the first embodiment, a comparison between Figs. 3 and 7 of the drawings immediately making this clear. In this embodiment the two rollers 1 6 are power-rotated about the corresponding axes a in the same directions B as in the first embodiment but it will immediately be realised that the relatively blunt and curved edges of the teeth 1 7 are now foremost with respect to the direction B and the relatively sharp straight edges thereof are rearmost with respect to the direction B.Aligned stub shafts 30 at the opposite ends of the tubular sleeve 1 5 of each roller 1 6 are rotatably received in the bearing housings 1 3 that are now supported by the carriers 29 but each stub shaft 30 at one end of each roller 1 6 is provided, at the side of said carrier 29 which faces the centre of the implement, with a corresponding toothed pinion 31. The two relatively spaced pinions 31 both have their teeth in driven mesh with those of a larger pinion 34 which is rotatably mounted on a horizontal stub shaft 33 at the same side of the carrier 29 concerned, the larger pinion 34 being principally above the two smaller pinions 31 as seen in Fig. 6 of the drawings.

the stub shaft 33 extends substantially horizontally parallel to the axes of rotation a of the two rollers 1 6 and the diameter of the larger pinion 34 may be as great as three times the diameter of each smaller pinion 31 although the embodiment which is being described does not exhibit this relationship.

The inter-meshing pinions 31 and 34 are contained in a somewhat flat gearbox 32 mounted at the side of the carrier 29 which faces the centre of the implement. The larger pinion 34 has its teeth in driven mesh with those of a considerably smaller pinion 35 which is also contained in an upper region of the gearbox 32 so as to be rotatable with a shaft 36, to which it is secured, about the longitudinal axis of the latter which axis again extends substantially horizontally parallel to the axes of rotation a of the two rollers 16.

However, the shaft 36 extends through an opening in the carrier 29 and into a further gear box 37 which is mounted on that surface of the carrier 29 that faces outwardly away from the centre of the implement, said gearbox 37 having a readily releaseable cover and functioning as a change-speed gear. The same shaft 36 is provided, inside the further gearbox 37, with a pinion 38 which lies alongside the pinion 35 but whose diameter is greater than that of the pinion 35. The pinion 38 has its teeth in driven mesh with those of a smaller pinion 39 carried by another parallel shaft 40 which extends from an upper region of the gearbox 37 through the carrier 29 and back for a short distance towards the centre of the implement (see Fig.5).It is emphasized that, to enable the transmission ratio in the further gearbox 37 to be varied, the cover of that further gearbox can quickly and easily be removed and the pinions 38 and 39 be interchanged on the two shafts 36 and 40 or be exchanged for at least one other pair of cooperating pinions of different sizes to both the pinions 38 and 39. This simple change-speed gear enables the rollers 1 6 to be powerrotated at any chosen one of a number of different speeds without having to change the driving speed of rotation that is applied to the shaft 40.

The end of the shaft 40 which is remote from the further gearbox 37 is splined or otherwise keyed and is connected (see Fig.5) by a telescopic transmission shaft 41 of known construction having universal joints at its opposite ends to a rotary output shaft 42 of the previously described gearbox 21 which gearbox 21 is modified so as to drive the rotary output shaft 42 that projects laterally from the side thereof that faces the carrier 29 which supports the gear boxes 32 and 37.

Apart from this modification, the gearbox 21 and the change-speed gear 22 which is located at the back thereof are identical to the previously described parts bearing the same reference numbers.

In the operation of the soil cultivating implement that has been described with reference to Figs. 5 to 7 of the drawings, that implement operates in the same general way as has already been described above. In this case, the adjusting mechanism 1 0A that has been described above interconnects the upper links 26 of the two quadrilateral linkages and the lugs which project rearwardly from the back of the hollow frame portion 1 adjacent the opposite ends of that frame portion. The construction is otherwise substantially identical to that which has already been described.

it will be noted from Fig.6 of the drawings that each lower link 27 is of angular, rather than straight, formation to avoid the links 27 fouling the lugs of the mechanism 1 OA when a shallow working depth of the members 3 is required. When, as is illustrated, the two quadrilateral linkages are parallelogram linkages, the rollers 1 6 and soil working members 3 may be bodily displaced upwardly and downwardly relative to one another without significant, if any, tilting so that the tubular sleeves 1 5 of both rollers 1 6 may remain firmly in engagement with the ground surface to substantially the same extent.The telescopic transmission shaft 41 which interconnects the gearbox 21 and the further gearbox 37 ensures that both rollers 16 will be positively rotated, without interruption, no matter what depth setting of the soil working members 3 is established by manipulation of the adjustment mechanism 1 or.

As the rollers 1 6 of this embodiment rotate in the directions B, the curved and relatively blunt edges of their teeth 1 7 first make penetrating contact with the soil and the resistance to displacement of that soil by the teeth 1 7 will, it will be realised, tend to assist forward displacement of the complete implement in the direction A.Once again, the relatively sharp rims 1 9 assist the teeth 1 7 in penetrating into the soil to such an extent that the outer surfaces of the sleeves 1 5 come into supported contact with the ground and, as in the first embodiment, any momentarily adhering clods of earth and/or agricultural debris will almost always very quickly be shed because of the movement of the teeth 1 7 of one roller between the teeth 1 7 of the other roller to such an extent that the outer curved edges of said teeth come closely adjacent to the tubular sleeves 1 5 of the respective "other" rollers.The rollers 1 6 again also perform their additional soil working, and particularly lump crushing, function and greatly assist in the uniform distribution of the soil cultivated by the implement throughout the working width thereof. The positive rotation of the two rollers 1 6 from the power take-off shaft of the cooperating tractor or other vehicle ensures that any stone or the like that might become jammed between the teeth 1 7 of two neighbouring groups on one of the roller 1 6 is very positively displaced by the intervening teeth 1 7 of a group carried by the other roller sleeve 15.

If desired, a reverse gear, not shown, can be incorporated in the drive transmission to the two rollers 1 6 of the embodiment of Figs.

5 to 7 of the drawsings so that, when required, the two rollers 1 6 can be powerdriven in directions opposite to the directions B. There are operating circumstances in which the facility for reverse rotation of the rollers 1 6 could be advantageous. It is not essential that the two pinions 31 should be of equal sizes. Provided the corresponding bearing housings 1 3 are re-positioned under such circumstances, the two rollers 1 6 will revolve at different speeds. It is not, of course, essential that the two rollers 1 6 should both have the same diameter and a roller assembly comprising two rollers of dissimilar diameters may, if desired, be employed.

Whilst being of particular utility in a soil cultivating implement of the kind that has been described, a roller assembly 1 6 in accordance with the invention may form part of an alternative soil cultivating impiement construction. Purely for example, instead of there being a plurality of soil working members 3 that are rotatable about individual substantially vertical, or at least upwardly extending, axes, those members may be replaced by a single rotatably mounted and substantially horizontally disposed shaft which is perpendicular, or at least transverse, to the direction A, that shaft being provided fixedly or releaseably and interchangeably with a plurality of projecting soil working tools in the form of teeth, spikes, blades, tines or the like.

Certain features off the soil cultivating implement and roller assembly constructions that have been described and/or that are illustrated in the accompanying drawings will be set forth in the following claims as inventive features. However, it is emphasized that the invention is not necessarily limited to those features and that it includes within its scope each of the parts of each soil cultivating implement and roller assembly construction that has been described, and/or that is illustrated in the accompanying drawings, both individually and in various combinations.

Claims (22)

1. A ground roller assembly in a soil cultivating implement, wherein that assembly comprises two rollers located substantially one behind the other in the intended direction of operative travel of the invention with at least one of those rollers having a central tubular part which bears upon the ground surface in the use of the implement.

2. A roller assembly as claimed in claim 1, wherein the implement is constructed and arranged to be connected to a tractor or other vehicle that is to move the implement over the ground and includes a transmission by which said two rollers are power-drivable from a power take-off shaft of said tractor or other vehicle.

3. A roller assembly as claimed in claim 1 or 2, wherein the roller assembly is arranged so as to be displaceable in bodily level relative to that of the remainder of the soil cultivating implement.

4. A roller assembly as claimed in claim 3, wherein the assembly is connected to the remainder of the soil cultivating implement through the intermediary of a pivotable quadrilateral linkage.

5. A roller assembly as claimed in claim 4, wherein the pivotable quadrilateral linkage is a parallelogram linkage.

6. A roller assembly as claimed in any preceding claim, wherein each of said two rollers comprises said central tubular part and each of those central tubular parts carries a plurality of groups of projecting teeth, the teeth being formed from shaped plates so as to have hollow constructions.

7. A roller assembly as claimed in claim 6, wherein the construction of each tooth is such that one edge thereof is relatively blunt whilst the opposite edge thereof is relatively sharp.

8. A roller assembly in a soil cultivating implement, wherein the roller, or at least one roller, comprises a plurality of projecting teeth formed from shaped plates so as to have hollow constructions, one edge of each tooth being relatively sharp whilst the opposite edge thereof is relatively blunt.

9. A roller assembly as claimed in any one of claims 6 to 8, wherein each tooth is formed from two punched and substantially symmetrically identical plates, those plates including substantially perpendicularly bent-over rims and also including further rims which abut one another to form said relatively sharp edge of the tooth.

10. A roller assembly as claimed in claim 9, wherein said edge of each tooth which is of relatively sharp formation is a substantially straight edge, the outer end of the tooth also being of relatively sharp construction and the relatively blunt edge of the tooth being of substantially regularly curved shape, this latter edge being afforded throughout at least the majority of its length by the first-mentioned substantially perpendicularly bent-over rims of the plates from which the tooth is constructed.

11. A roller assembly as claimed in claim 10, wherein a chord to said substantially regularly curved edge of each tooth is inclined to a line extending radially from the intended axis of rotation of the corresponding roller to the junction between said curved edge and the outer end of the tine at an angle of not less than substantially 20 and not more than substantially 30 , the outer end of each tooth coinciding with an arc of an imaginary circle centered upon the same intended axis of rotation.

1 2. A roller assembly as claimed in any preceding claim, wherein the teeth are arranged in groups, or in said groups, and each group comprises three teeth which are spaced apart from one another around the intended axis of rotation of the corresponding roller at intervals of substantially 120 .

1 3. A roller assembly as claimed in claim 1 2 when read as directly or indirectly appendant to claim 8, wherein the relatively blunt edge of each tooth is directed towards the relatively sharp edge of the next tooth in the same group of teeth considered rotationally around the corresponding roller.

14. A roller assembly as claimed in any preceding claim, wherein the assembly comprises two rollers located substantially one behind the other in the intended direction of operative travel of the implement, the rollers being in parallel relationship with one another and the spacing between them being such that the minimum distance between the surfaces of central tubular parts thereof is equal, of substantially equal, to the diameter of one of those tubular parts.

1 5. A roller assembly as claimed in any preceding claim, wherein the roller, or at least one of the rollers, has a central tubular part whose external diameter has a magnitude of substantially 1 5 cms.

1 6. A rOller assembly as claimed in claim 6 or in any one of claims 7 to 1 5 when read as appendant to claim 6, wherein each tooth extends outwardly from the corresponding central tubular part by a distance whose magnitude is substantially equal to the external diameter of that tubular part.

1 7. A roller assembly as claimed in claim 6 or in any one of claims 7 to 1 6 when read as appendant to claim 6, wherein the assembly comprises two rollers located substantially one behind the other in the intended direction of operative travel of the implement, and wherein the groups of teeth carried by said two rollers are so disposed on central tubular parts of those rollers that a group forming part of one roller projects substantially mid-way between two groups forming part of the other roller, the outer end of each tooth being closely adjacent to the surface of the central tubular part of the other roller at its closest point of approach to that central tubular part.

1 8. A roller assembly as claimed in any preceding claim, wherein a transmission, or said transmission, by which the two rollers are power-rotatable is part of a drive transmission to soil working tools of the soil cultivating implement.

1 9. A roller assembly as claimed in claim 18, wherein the drive to the rollers includes a telescopic transmission shaft interconnecting a gearbox located substantially centrally of the implement and a gearbox located adjacent one axial end of each roller.

20. A roller assembly as claimed in claim 19, wherein the gearbox located adjacent one axial end of each roller includes a changespeed gear.

21. A roller assembly as claimed in any preceding claim, wherein the assembly is located at the rear of the remainder of the soil cultivating implement with respect to the intended direction of operative travel of that implement, the latter comprising a row of soil working members that extends substantially horizontally perpendicular, or at least transverse, to the intended direction of operative travel of the implement with each mem ber arranged so as to be rotatable about a corresponding substantially vertical, or at least upwardly extending, axis.

22. A ground roller assembly in a soil cultivating implement substantially as hereinbefore described with reference to Figs. 1 to 4 or with reference to Figs 5 to 7 of the accompanying drawings.