IE44149B1 - Improvements in or relating to rotary harrows - Google Patents

Abstract

Soil cultivating implements are disclosed of the kind which have a frame that is at least partly supported by ground wheels during operation of the implement and which also have at least one group of soil working or cultivating members that are rotatable about upwardly extending axes, the group being carried by the frame in a row that extends in a direction which is transverse to the intended direction of operative travel of the implement. At least two groups of the soil working or cultivating members are carried by the frame in side-by-side relationship and at least one group is upwardly tiltable relative to at least one other group to bring the implement from a working position to a position that is suitable for the inoperative transport thereof.

Description

This invention relates to rotary harrows of the kind which comprise a frame that is at least partly supported by ground wheels during operation of the harrow and which also comprises at least one group of soil working members that are rotatable about nonhorizontal axes, said groups being arranged in a row that extends transverse to the intended direction of operative travel of the harrow.

According to the invention, there is provided a rotary harrow of the type comprising a frame that is at least partly supported by groups of ground wheels during operation of the harrow, and which also comprises groups of soil working members that are rotatable about non-horizontal axes, each group of soil working members being arranged in a row extending transversely of the intended direction of operative travel of the harrow, wherein there are two groups of-wheels disposed at opposite sides of an imaginary vertical plane of substantial symmetry of the harrow that extends parallel to its intended direction of operative travel, said ground wheels being adjustable in level relative to other parts of the harrow to bring the latter from a working position to a position that is suitable for the inoperative transport thereof and vice versa, and wherein at least two groups of soil working members are provided and are carried by the frame in end-to-end relationship, at least one of said two groups being upwardly pivotable relative to at least the other groups thereof as a step in bringing the harrow from said working position to said position that is suitable for the operative transport thereof. - 2 44149 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:5 Figure 1 is a plan view of a rotary harrow in accordance with the invention connected to the rear of an agricultural tractor, a seed drill being provided at the rear of the harrow.

Figure 2 is a side elevation, as seen in the direction indicated by an arrow II, in Figure 1, an operative position of the harrow being illustrated in full lines and an inoperative transport position thereof in broken lines, Figure 3 is a partial front elevation of the harrow to an enlarged scale as compared with Figures 1 and 2, Figure 4 is a plan view as seen in the direction indicated by an arrow IV in Figure 3, and Figure 5 is a section taken on the line V-V in Figure 4.

Referring to the accompanying drawings, the rotary harrow that is illustrated therein comprises a frame having two beams 1 and 2 major portions Ί of which are forwardly convergent, with respect to the intended direction of operative travel of the harrow which is indicated in Figures 1 and 2 by the reference A. The frame beams 1 and 2 are substantially horizontally disposed and include rear portions 3 that are in 44^48 substantially parallel relationship with one another and with the direction A. The leading ends of the major portions 4 of the beams 1 and 2, which portions are both straight, are interconnected at their junction point by a fork 5 whose two limbs are substantially horizontally disposed, in vertically spaced apart relationship, so as to project forwardly from the beams 1 and 2 with respect to the direction A. A substantially horizontal beam 6 perpendicularly interconnects the rear portions 3 of the beams 1 and 2 close to the rearmost ends of said portions 3. A hollow box-section frame portion 7 is connected to the lower surfaces of the two frame beams 3 so as to extend substantially parallel to the frame beam 6 at a location which is a short distance in advance of that beam 6 with respect to the direction A. The connection between the hollow frame portion 7 and the portions 3 of the two beams 1 and 2 is effected by upright substantially triangular plates 8 that are fastened to the top of the hollow frame portion 7 at four locations which are close to the front and rear of the frame portion 7 with respect to the direction A and close to the opnosite ends of that frame portion. The rear substantially parallel portions 3 of the two frame beams 1 and 2 are provided, at locations that are respectively in front of, and behind, the corresponding plates 8, with four obliquely upwardly and outwardly inclined arms 9, the upper and outer ends of the four arms 9 being pivotally connected to four corresponding vertical plates 11 by four pivot pins 10 which are aligned, in two pairs, so as to define two parallel axes that are both substantially parallel to the direction A and that pass above the hollow frame portion 7 quite close to the opposite ends of the latter.

The four plates 11 are arranged in two pairs and each pair is secured to a corresponding one of two hollow box-section frame portions 12 that are both of similar construction to the hollow frame portion / and that, when the harrow is in use, have their longitudinal axis of the central hollow frame portion 7 and in perpendicular, or substantially perpendicular, relationship with the direction A. The two hollow frame portions 12 are, of course, turnable upwardly and downwardly about the axes defind by the corresponding pairs of pivot pins 10 relative to the central frame portion 7. Each pair of plates 11 is provided, very close to the tops of those plates, with transverse pieces 13 that project towards one another from the plates 11 concerned in perpendicular relationship with the planes of those plates. Upright plates 14 are mounted at the six ends of the three hollow frame portions and 12 and supports 15, which serve as tie beams, extend 44140 between each pair of transverse pieces 13 and the upright plate 14 which is at the outermost end of the same hollow frame portion 12 as that which is provided with the plates 11 that carry said transverse pieces 13. There is a total of four of the supports 15 and it will be seen from the drawings that they are arranged in corresponding pairs that are gently convergent from the transverse pieces 13 to the respective upright plates 14. Moreover, when the harrow is disposed in its operative position, each pair of supports 15 is inclined downwardly at a small angle to the horizontal from the corresponding transverse pieces 13 to the corresponding upright plate 14. Each hollow frame portion 12 is provided, at a location which is approximately one-quarter of the way along that portion 12 towards the central frame portion 7 from the outermost end thereof, with a vertical plate 16 (Figure 1), each plate 16 extending rigidly between the top of the frame portion 12 concerned and the lower surfaces of the two overlying supports 15. The fronts of the two vertical plates 16 with respect to the direction A are both secured to the rear ends of corresponding' forwardly convergent tubular supports 17 whose leading ends carry corresponding substantially horizontal sleeve bearings 18. The sleeve bearings 18 at the leading ends of the tubular supports 17 with respect to the direction A are considerably closer to an imaginary vertical plane of substantial,but not exact, symmetry of the harrow which extends parallel to 44140 the direction A than are the vertical plates 16 at the rearmost ends of said tubular supports 17. A horizontal beam 21 is detachably secured to the tops of the convergent portions 4 of the two frame beams 1 and 2 so as to extend perpendicular to the direction A and so as to project for equal distances from the opposite side of the imaginary vertical plane of substantial symmetry of the harrow that has just been referred to.

The opposite ends of the beam 21 carry corresponding forks 20 whose vertically disposed limbs are spaced apart from one another in the direction A and each fork 20 has a corresponding one of the two sleeve bearings 18 turnably mounted between its limbs by a corresponding horizontal pivot pin 19 whose axis is coincident with that defined by one pair of the four pivot pins 10 that is located behind it relative to the direction A. Thus, the pins 10 at the inner ends of the outer pivotably mounted hollow frame portions 12 and the corresponding pivot pins 19 are located one behind the other with respect to the direction A. It will be noted that the horizontal beam 21 is located substantially midway between the opposite ends of the convergent portions 4 of the frame beams 1 and 2.

Stub shafts 22 that are horizontally aligned in a direction that is perpendicular to the direction A are turnably mounted in bearings bolted to the lower surfaces of the rear substantially parallel portions 3 of the two beams 1 and 2 at locations which are immediately behind 44148 the frame beam 6 with respect to the direction A (see particularly Figures 4 and 5 of the drawings).

The aligned stub shafts 22 project towards one another from their bearings and their inner ends are secured to corresponding arms 23 which project upwardly and rear-wardly therefrom with respect to the direction A.

The rear ends of the two arms 23 are secured to a strip-shaped beam 24 which serves as an axle beam for the rotary mountings of two ground wheels 25 whose axes of rotation are substantially horizontally coincident in a direction that is substantially perpendicular to the direction A. As can be seen in outline in Figure 1 of the drawings, the rotary mountings of the two ground wheels 25 are adjustable towards and away from one another along Opposite end regions of the beam 24 so that the distance between said ground wheels 25 and/or the positions thereof relative to the path of travel of the whole harrow can be adjusted to facilitate use of the harrow in various row cultures. Each stub shaft 22 is provided, between its bearings and the corresponding arm 23, with an upwardly and forwardly inclined arm 26 whose upper end is pivotally connected to the free end of the piston rod of a corresponding hydraulic piston and cylinder assembly 27. Each of the two assemblies 27 extends substantially parallel to the direction A and has the leading base end of its cylinder pivotally connected to a coresponding arm 28 that projects upwardly from the portion 3 of the frame beam 1 or 2 concerned, the lower ends of the arms 28 being turnable relative to said beam portions 3 about an axis that is substantially horizontally parallel to the frame beam 6. The upper end of each pivotally mounted arm 28 is connected at a level above that of the corresponding assembly 27, to the top of a corresponding upright arm 29 by a helical tension spring 28A that is substantially, although not exactly, parallel to the direction A. The two upright arms 29 are rigidly secured to the frame beam 6 at locations close to the opposite ends of that frame beam. Two pairs of lugs 30 project rearwardly from the back of the frame beam 6 at positions which are spaced only short distances inwardly from the opposite ends of said frame beam and these serve for the connection to the harrow of a seed drill 59 or other tool or implement in a manner that will be further described below. The two pairs of lugs 30 are spaced at equal distances from the midpoint of the beam 6.

Each of the three hollow frame portions 7 and 12 has a plurality of corresponding substantially vertical or at least non-horizontally, extending shafts 31 rotatably mounted therein in a single row, the longitudinal axes of the shafts 31 being spaced apart from one another ! I 4414 9 at regular distances which preferably, but not essentially, have magnitudes of substantially 25 centimetres. In the embodiment which is being described, there are twelve of the shafts 31 in respect of each of the three hollow frame portions 7 and 12. The shafts 31 are rotatably journalled in bearings carried by upper and lower walls of the hollow frame portions 7 and 12 and each shaft 31 projects from beneath the bottom of the corresponding frame portion. The lowermost end of the downwardly projecting portion of each shaft 31 is secured to the midpoint of a corresponding horizontal or substantially horizontal tine support 32, said tine support 32 having sleevelike holders at its opposite ends in which fastening portions of two correspond!ng rigid and downwardly extending tines 33 are firmly but releasably secured in a manner which it is not necessary to describe for the purposes of the present invention. Each pair of tines 33 constitutes, together with the corresponding support 32 and its tine holders, a rotary soil working member 35. Each of the shafts 31 is provided, inside the corresponding hollow frame portion 7 or 12, with a straight-toothed or spur-toothed pinion 34, the pinions 34 being so arranged that each one of them has its teeth in mesh with those of its neighbour, or both of its neighbours, in the single row thereof that corresponds 44148 to the hollow frame portion 7 or 12 concerned.

In each of the two outer hollow frame portions 12, one of the centre pair of shafts 31 has an upward extension through the top of said frame portion into a gear box 36 that is bolted into the top of that frame portion. Bevel pinions (not visible in the drawings) located inside each gear box 36 place the upward extension of the corresponding shaft 31 in driven connection wi,th a substantially horizontal shaft (not visible) that extends parallel to the length of the frame portion 12 concerned and thus substantially perpendicular to the direction A. One end of the substantially horizontal shaft that has just been referred to projects into a change-speed gear 37 together with one end of a corresponding overlying and parallel rotary input shaft 38 of the gear box 36.

It is not necessary to describe the change-speed gears 37 in detail for the purposes of the present invention but it should be noted that, in each change-speed gear 37, the ends of the corresponding two substantially horizontal shafts are splined or otherwise keyed to receive the hubs of pairs of interchangeable and/or exchangeable straight-toothed or spur-toothed pinions. The transmission ratio between the input shaft 38 of the gear box 36 and the underlying row of shafts 31 will depend upon the pinion arrangement selected in the 44140 corresponding change-speed gear 37 and this arrangement thus governs the speed of rotation of the soil working members 35 that are driven from each gear box 36 during the operation of the harrow. The two gear boxes 36 and their rotary input shafts 38 are arranged substantially symmetrically at the opposite side of the imaginary vertical plane of substantial symmetry of the harrow that extends parallel to the direction A and each input shaft 38 is coupled by a corresponding universal joint 36 to one end of a corresponding telescopic transmission shaft 40. The telescopic transmission shafts 40 extend from the universal joints 39 towards the opposite sides of a gear box 42 that is mounted on top of the central frame portion 7 and into which projects an upward extension of one of the central pair of shafts 31 that corresponds to said frame portion 7, The gear box 42 is thus mounted just to one side of the vertical plane of substantial symmetry of the harrow that extends parallel to the direction A. The central gear box 42 has a rotary input shaft 34 that projects from the front thereof in substantially the direction A, the projecting end of said shaft 43 being splined or otherwise keyed' to enable it to be driven in the manner that will be described below. Two rotary output shafts 41 project from opposite sides of the central gear 44148 box 42 and are horizontally aligned in a direction parallel to the length of the hollow frame portion 7 and thus in a direction that is substantially perpendicular to the direction A. The input shaft 43 of the gear box 42 directly drives the two input shafts by way of co-operating bevel pinions (not visible) that are contained inside the gear box 42 and said shafts 41 are drivingly connected, in turn, to the inner ends of the two telescopic transmission shafts 40 by way of corresponding universal joints 40A. The rear of the central gearbox 42 with respect to the direction A carries a change-speed gear 44 and the rearmost end of the rotary input shaft 43 projects into said change-speed gear 44, together with the rearmost end of an underlying and parallel shaft that is not visible in the drawings, the latter non-i1 lustrated shaft being drivingly connected by bevel pinions to the aforementioned upward extension of one of the centre pair of shafts 31 that corresponds to the hollow frame portion 7. The ends of the two shafts that project rearwardly into the change-speed gear 44 are both splined and are arranged to receive chosen pairs of interchangeable and/or exchangeable pinions in the manner as has already been briefly explained in relation to the two change-speed gears 37.

The forwardly projecting splined or otherwise keyed end of the rotary input shaft 43 of the gear box 42 is driven from the rear end of a telescopic transmission shaft 46 through the intermediary of a universal joint 45, the leading end of said shaft 46 being, in turn, driven from the rear end of a short rotary shaft 47 by a further universal joint 47A. As can be seen in the drawings, the short rotary shaft 47 extends substantially horizontally parallel to the direction A and is rotatably journalled in a horizontal bearing 48 that is mounted on top of the beam 21 midway between the convergent portions 4 of the two frame beams 1 and 2. When the harrow is in use, the leading splined or otherwise keyed end of the shaft 47 is 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 further telescopic transmission shaft 48A having universal joints at its opposite ends. The leading plate 11 of the pair of those plates that corresponds to one of the hollow frame portions 12 has the free end of the piston rod of a double-acting piston and cylinder assembly 49 pivotally connected to substantially its uppermost point. The base of the cylinder of the same assembly 49 is pivotally connected to one end of a strip 50 that extends substantially horizontally perpendicular to the direction A on top of a horizontal base portion of a bracket 51, the limbs of said bracket 51 diverging steeply downwardly away from its base and having their free ends rigidly secured to the rear substantially parallel portions 3 of the two frame beams 1 and 2.

A second substantially symmetrically arranged doubleacting piston and cylinder assembly 49 pivotally interconnects the opposite end of the strip 50 and the top of the leading plate 11 that corresponds to the other of the two hollow frame portions 12.

Each of the six upright plates 14 at the opposite ends of the three hollow frame portions 7 and 12 has a corresponding arm 52 arranged alongside it, the two arms 52 that correspond to each of the three hollow frame portions 7 and 12 being turnable upwardly and downwardly relative to the plates 14 carried by that frame portion about substantially horizontally aligned strong pivots that are disposed at the fronts of said plates 14 with respect to the direction A (see particularly Figure 5). Each plate 14 is formed, near its rearmost edge, with a curved row of holes that are equidistant from the axis defined by the corresponding pair of strong pivots and each arm 52 is formed with a single hole that is at the same distance from said axis and which can thus be brought into register with any chosen one of the holes in the immediately adjacent plate 14 by turning that arm 52 to an appropriate angular position about the corresponding strong pivot. Horizontal bolts 54, or equivalent horizontal locking pins, are provided for entry through the holes in the arms 52 and the selected holes in the plates 14. A rotatable supporting member in the form of an open-work ground roller 53 is rotatably mounted between rearmost downwardly directed portions of each pair of arms 52 and it will be seen that the particular angular positions of the arms 52 relative to the corresponding frame portions 7 and 12 that are fixed by the bolts 54 or equivalent locking pins dictate the levels of the substantially horizontal axes of rotation of the three rollers 53 relative to those of the corresponding hollow frame portions 7 and 12 and thus the maximum depths of penetration of the tines 33 into the soil that are possible during the operation of the implement. Two substantially vertical shield plates 55 that both extend substantially parallel to the direction A are located immediately beyond those two ends of the outer hollow frame portions 12 that are furthest remote from one another, said shield plates 55 being shaped so that lower edge regions thereof will slide over the ground surface in the direction A (see Figure 2) and being arranged so that the plates will be able to turn upwardly and downwardly to match undulations in the surface of the soil that they may meet with during the operation of the harrow. -1644149 To this latter end, each shield plate 55 is pivotally connected by a corresponding pair of arms 56 (Figure 1) to a pair of mountings on the top of the corresponding hollow frame portion 12, the pivotal connections being such as to define substantially horizontal axes that are substantially parallel to the direction A.

In the use of the rotary harrow that has been described, the fork 5 is connected to a tow bar at the rear of an agricultural tractor or other operating vehicle and the hydraulic piston and cylinder assemblies 27 and 49 are placed in operative connection with the hydraulic system of the same tractor or other vehicle by way of ducts that are not illustrated in the accompanying drawings. The leading end of the telescopic transmission shaft 48A is placed in driven connection with the rear power take-off shaft of the same tractor or other operating vehicle by way of a universal joint which is not visible in the drawings so that the rotary soil working members 35 that correspond to the three hollow frame portions 7 and 12 may be driven from said tractor or other operating vehicle by way of the previously described transmission. Before work commences, the maximum depths to which the tines 33 of the members 35 can penetrate into the soil are set by bringing the axes of rotation of the three 441^9 rollers 53 to -appropriate levels relative to the three hollow frame portions 7 and T2 by entering the bolts 54 or equi-valent locking pins through appropriate holes in the upright end plates 14 of said frame portions 7 to 12. Moreover, the piston rods of the hydraulic assemblies 27 are set in positions of extension relative to their cylinders which will maintain the common axis of rotation of the two ground wheels 25 at a desired level relative to that of the central hollow frame portion 7. It will be noted'that, in this connection, the two pivotably mounted arms 28 can bear against stops 57 which are carried by the rear substantially parallel portions 3 of the two frame beams 1 and 2 at locations which are just in front of said arms 28. Before a cultivating operation actually commences, the adjustments that will be made will include attention to the three change-speed gears 37 and 44 to ensure that the three groups of rotary soil working members 35 will revolve at a desired speed in response to a more or less standard input speed of rotation that is applied to the shaft 43 of the central gear box 42. The speed of rotation that will be chosen for the members 35 will depend upon the nature and condition of the soil that it is to be cultivated and the consistency which it is desired that it should have at the end of the operation. The three change-speed gears 37 and 44 will, almost invariably, be adjusted to give the same speeds of rotation for all of the members 35 of the three groups but it is noted that under exceptional operating conditions, one of the three change-speed gears could be set for a speed of rotation of the corresponding group of members 35 that is different to the speeds of rotation of the other two groups or all three change-speed gears 37 and 44 could be set for different speeds of rotation of the corresponding groups of members 35. Only very rarely indeed will the operating circumstances make different speeds of rotation amongst the three groups of members 35 desirable and, in the vast majority of operations, all of the members 35 of the three groups will rotate at the same speed.

Due to the intermeshing arrangement of the pinions 34 inside the three hollow frame portions 7 and 12, each pinion 34, and the corresponding soil working members 35, will, during a cultivating operation, rotate in the opposite direction to that of its immediate neighbour, or to those of both its immediate neighbours, in the same group of members 35. In the embodiment of Figures 1 to 5 of the drawings which is being described, there are three groups of the soil working members 35, each group comprising twelve of the members 35 so that there is a total of thirty-six of those members that are arranged, at least as seen in the plan view of Figure 1 of the drawings, in a single row that extends substantially perpendicular to the direction A. Actually, the row of thirty-six members 35 will not be truly straight during the operation of the implement, except at random momentary occasions, because of the upward and downward pivotal movements of the outer frame portions 12 and the corresponding groups of members 35 that will take place about the two axes that are defined by the two sets of pivot pins 10 and 19 relative to the central hollow frame portion 7. Since the free ends or tips of the two tines 33 of each soil working member 35 are spaced apart from one another by a distance which is a little in excess of the regular spacing (preferably substantially 25 centimetres) between the axes of rotation of the shafts 31 in each group of members 35, said members work overlapping strips of soil during operative progress of the harrow in the direction A and a single broad strip of worked soil results. The three groups of members 35 substantially adjoin or overlap one another so that no major discontinuities in the broad strip of worked soil are caused in line, in the direction A, with the junctions between the hollow frame portion 7 and the two hollow frame portions 12. Generally speaking, the harrow cultivates the soil in such a way that the surface of the strip which has been cultivated thereby is uninterrupted throughout its width. The two shield 44148 plates 55 at the opposite ends of the row of thirtysix members 35 serve to minimise ridging of the soil at the margins of the strip that is worked by the harrow and also co-operate with the neighbouring members 35 in preventing loose stones and other potentially dangerous items from being flung laterally of the path of travel of the harrow by the rapidly moving tines 33.

With the preferred spacing between the axes of rotation of neighbouring shafts 31 that has been mentioned above, the harrow of Figures 1 to 5 of the drawings has an overall working width of substantially 9 metres since each of the three groups of members 35 has a working width of substantially three metres. These particular dimensions are not, of course, essential. Hollow frame portions and corresponding groups of the members 35 may be employed which have effective widths of 2.0 metres or 2.5 metres or widths greater than 3.0 metres, the number of members 35 per group being reduced or increased as required. If required, the detachably mounted horizontal beam 21 may be replaced by alternative beams which are similar except for their dimensions, such alternative beams, if required, being connected to the portions 4 of the frame beams 1 and 2 at locations and are further to the rear, or further to the front, with respect to the direction A, than is the beam 21. Figure 4 of the drawings - 21 shows two alternative fastening holes 51A for use with such alternative beams. Two arms 58 have their leading ends pivotally connected to the horizontal beam 6 by aligned pivot pins that co-operate with the pairs of rearwardly directed lugs 30. The arms 58 form parts of, or are provided for use with an agricultural implement that is arranged behind the rotary harrow with respect to the direction A. Figures 1 to 5 of the drawings illustrate the provision of a seed drill 59 as the agricultural implement but alternative implements can equally well co-operate with the rotary harrow. The seed drill 59 which is illustrated is pivotally connected to the beam 6 of the harrow by way of the arms 58 and comprises a horizontal beam 60 which, when the harrow and drill combination is in use, extends substantially perpendicular to the direction A and which has a plurality, such as twelve, of sowing units 61 connected to it at regularly spaced intervals along its length. The seed drill 59 is a precision seed drill whose construction and operation it is not necessary to describe for the purposes of the present invention, the sowing units 61 being units that are known per se.

As previously mentioned, each of the two groups of twelve soil working members 35 that corresponds to the two outer hollow frame portions 12 can pivot relative 414 9 to the hollow central frame portion 7, to match undulations in the surface of the ground, by turning upwardly and downwardly about the axis that is afforded by the corresponding pair of pivot pins 10 and the corresponding pivot pin 19, those three pivot pins being spaced apart from one another in the direction A with the pivot pin 19 foremost. The ground wheels 25 are bodily pivotable to a limited extent relative to the frame of the harrow about the axis defined by the substantially horizontal stub shafts 22. The arrangement is, in fact, such that the tension springs 28A tend to turn the ground wheels 25 bodily downwards towards the ground surface and oppose bodily upward displacements of said wheels. When the harrow is to be transported from one place to another with performing any working operation, the piston rods of the double acting hydraulic piston and cylinder assemblies 49 are retracted into their cylinders and this causes the two outer hollow frame portions 12, and the parts which they carry, to turn upwardly about the axes that are defined by the pivot pins 10 and 19 until they reach the positions that are shown in broken lines in Figures 2 and 3 of the drawings. It will readily be appreciated that this reduces the overall width of the harrow to little more than the width of the path of travel of the agricultural tractor in other vehicle which operates and tows it. In the case of the particular embodiment which is illustrated in Figures 1 to 5 of the drawings, the inoperative transport width of -234 414 9 the rotary harrow alone is substantially 4.0 metres.

When the outer hollow frame portions 12 have been tilted upwardly, the piston rods, of the two assemblies 27 are extended from their cylinders and this causes the two ground wheels 25 to be displaced bodily downwards with the result that the frame is raised relative to the ground surface. This position of the ground wheels 25 is shown in broken lines in Figure 2 of the drawings and it will be evident from a comparison between that position and the operative position that is also shown in the same Figure but in full lines, that the soil working members 35 of the central group thereof have their tines raised well clear of contact with the ground surface. The harrow can then be transported by towing it forwardly in the direction A.

The horizontal beam 60 of the precision seed drill 59 is, in fact, formed in three separate portions and it will be seen from Figure 1 of the drawings that the outer two of those three portions can be turned forwardly through substantially 90° about the axes that are defined by substantially vertical hinges 62, This greatly reduces the width of the seed drill for inoperative transport purposes and brings it to substantially the position thereof that is shown in broken lines in Figure 1 of the drawings, it being remembered that the outer -2444148 hollow frame portions 12 of the rotary harrow will already have been tilted upwardly about the axes defined by the pivot pins 10 and 19. Naturally, if the hollow frame portions or at least the central hollow frame portion 7, of the rotary harrow were of smaller width than in the embodiment that has been described, the overall transport width of that harrow alone would be smaller as would the overall transport width of a combination of the harrow with an implement such as a matchingly dimensioned seed drill. Under such circumstances, the overall transport width could be 3.0 metres or less.

Claims (32)

1. I. A rotary harrow of the type comprising a frame that is at least partly supported by groups of ground wheels during operation of the harrqw, and which also comprises groups of soil working members 5 that are rotatable about non-horizontal axes, each group of soil working members being arranged in a row extending transversely of the intended direction of operative travel of the harrow, wherein there are two groups of wheels disposed at opposite sides of an imaginary vertical plane of substantial symmetry of the harrow that 10 extends parallel to its intended direction of operative travel, said ground wheels being adjustable in level relative to other parts of the harrow to bring the latter from a working position to a position that is suitable for the inoperative transport thereof and vice versa, and wherein at least two groups of soil working members are provided 15 and are carried by the frame in end-to-end relationship, at least one of said two groups being upwardly pivotable relative to at least the other groups thereof as a step in bringing the harrow from said working position to said position that is suitable for the operative transport thereof. 20

2. A harrow as claimed in claim 1, wherein three groups of soil working members are carried by the frame in end-to-end relationship, the two outer groups of the soil working members being located at opposite sides/ends of a central group thereof and being both 25 pivotable relative to said central group to bring the harrow from its working position to a position that is suitable for the inoperative transport thereof and vice versa. 44148

3. A harrow as claimed in claim 1 or 2, wherein at least one group of the soil working members is pivotable about an axis that extends substantially parallel to the intended direction of operative travel of the harrow and that is located at or near one end of said row.

4. A harrow as claimed in any preceding claim, wherein at least one group of the soil working members is pivotably supported at two relatively spaced points, said points being disposed ene behind the other with respect to the intended direction of operative travel of the harrow.

5. A harrow as claimed in any preceding claim, wherein each group of soil working members is carried by a corresponding frame portion that extends perpendicular, or at least transverse, to the intended direction of the operative travel of the harrow, said frame portions being in line with one another and the neighbouring ends of said frame portions being in the immediate proximity of one another when the harrow occupies its working position.

6. A harrow as claimed in claim 5, wherein at least one frame portion and the corresponding group of soil working members is pivotable relative to a further frame portion and its group of soil working members, the axis about which the pivotal movement can take place being afforded by at least one pivot point located at or near one end of one of the frame portions and a second pivot point that is disposed at or near one end of a support which is' fastened to the frame portion concerned at a location between the opposite ends of that frame portion.

7. A harrow as claimed in claim 6, wherein said support extends obliquely forwardly with respect to the intended direction of operative travel of the harrow from its fastening location to said frame portion and in a direction towards said imaginary vertical plane of substantial symmetry of the harrow that extends parallel to the intended direction of operative travel thereof.

8. A harrow as claimed in claim 5 or 7, wherein the location at which said support is fastened to the frame portion is spaced along that frame portion from the outer end thereof by a distance equal to substantially one-quarter of the total length of the frame portion.

9. A harrow as claimed in any one of claims 5 to 8, wherein the leading end of said support, with respect to the intended direction of operative travel of the harrow, is pivotally connected to a transverse frame beam in such a way that the pivot point is located on a line that extends parallel to the intended direction of operative travel of the harrow and that passes through, or near to, one end of the frame portion concerned. 4 414 9

10. A harrow as claimed in any one of claims 6 to 9, wherein the pivotable frame portion is provided with supports that are convergent, from locations close to the pivotal connection of the frame portion to a further frame portion, towards a point on the frame portion which is spaced from said locations, the convergent supports being inclined to the horizontal so as to extend downwardly away from said locations.

11. A harrow as claimed in any one of claims 6 to 10, wherein the or each upwardly pivotable group of soil working members is arranged to be tiltably displaced by a hydraulic piston and cylinder assembly that interconnects an end region of said frame portion and the frame of the harrow.

12. A harrow as claimed in any preceding claim wherein the frame comprises two beams that extend generally in the intended direction of operative travel of the harrow, said beams comprising rear portions that are substantially parallel to one another and forwardly convergent portions that are disposed in front of said rear portions with respect to said direction, the convergent portions both being substantially straight and the leading ends of said convergent portions comprising a coupling point for connecting the harrow to the tow bar of a tractor or other vehicle. - 29 44149

13. A harrow as claimed in claim 12 when read as appendant to claim 2, wherein the frame portion that corresponds to the central group of soil working members is connected to the substantially parallel rear portions of said frame beams.

14. A harrow as claimed in either claim 12 or 13 when read as appendant to claim 9, wherein the beam to which the supports of the pivotable frame portions are pivotally connected is carried by the convergent portions of said frame beams.

15. A harrow as claimed in any preceding claim, wherein said two grounded wheels are disposed behind the groups of soil working members with respect to the intended direction of operative travel of the harrow.

16. A harrow as claimed in any preceding claim, wherein the .axes of rotation of said two ground wheels are substantially horizontally coincident and means is provided whereby the distance between said two ground wheels can be adjusted.

17. A harrow as claimed in any preceding claim, wherein said two ground wheels are arranged to be bodily displaceable together, upwardly and downwardly, relative to said frame.

18. A harrow as claimed in any preceding claim, wherein said two ground wheels are bodily displaceable in at least one direction against resilient opposition.

19. A harrow as claimed in any preceding claim, wherein said two ground wheels are bodily displaceable about an axis that extends substantially perpendicular to the intended direction of operative travel of the harrow, said axis being parallel or substantially parallel to the axes of rotation of the ground wheels themselves.

20. A harrow as claimed in claim 17 or in either claim 18 or claim 19 when read as appendant to claim 17 wherein said two ground wheels are bodily displaceable in a pivotal manner in at least one direction by a hydraulic piston and cylinder assembly and a spring extends between an arm that is pivotally connected to the frame and to said hydraulic piston and cylinder assembly and a fixed anchorage on said frame, said arm coming into contact with a stop when the ground wheels are bodily displaced upwardly by the hydraulic piston and cylinder assembly.

21. A harrow as claimed in claim 20, wherein said spring is arranged to urge the ground wheels bodily in a downward direction,

22. A harrow as claimed in any preceding claim, wherein a rotatable supporting member is arranged behind each group of soil working members, each rotatable supporting member extending throughout substantailly the whole of the working width of the corresponding group of soil working members.

23. A harrow as claimed in claim 22, wherein each rotatable supporting member is upwardly and downwardly displaceable in position, relative to a frame portion that carries the corresponding group of soil working 5 members, by means of arms located at or near the opposite ends of said frame portions.

24. A harrow as claimed in any preceding claim, wherein the rear of said frame with respect to the intended direction of operative travel of the harrow 10 is provided with at least one coupling point for the connection thereto of an implement that may be used in combination with the rotary harrow.

25. A harrow as claimed in any preceding claim, wherein the rotary drive to the soil working members of 15 the or each pivotable group thereof is effected by way of a driving shaft that is mounted on said frame and a shaft that extends lengthwise along a frame portion which supports the group of soil working members or a corresponding group thereof. 20 25. A harrow as claimed in claim 25 when read as appendant to claim 2, wherein the drive transmission to each pivotable group is effected via a gear box mounted on a non-pivotable frame portion of said frame that carries said central group of the soil 25 working members.

26. 27. A harrow as claimed in claim 25 or 26, wherein the drive transmission to the soil working members comprises a shaft that extends substantially parallel to the intended direction of operative travel of the 44140 harrow, said shaft being rotatably supported in a bearing carried by the frame.

27. 28. A harrow as claimed in claim 27, wherein, as seen in plan, the shaft that extends substantially 5 parallel to the intended direction of operative travel of the harrow substantially coincides with an imaginary vertical plane of substantial symmetry of the harrow that also extends parallel to said direction.

28. 29. A harrow as claimed in either claim 27 or 28 when 10 read as appendant to claim 9, wherein the driving shaft that extends substantially parallel to the intended direction of operative travel of the harrow is supported by the beam to which are pivotally connected the leading ends of the supports of the frame portions that carry the 15 pivotable groups of soil working members.

29. 30. A harrow as claimed in any preceding claim, wherein a drive transmission to each group of soil working members includes a corresponding change-speed gear. 20

30. 31. A harrow as claimed in any preceding claim, wherein the harrow had a width of between substantially 3.0 and substantially 4.0 metres inclusive when it is disposed in a position that is suitable for the inoperative transport thereof. 4 4140

31.

32. A harrow of the kind set forth, substantially as hereinbefore described with reference to the accompanying drawings.