GB2136662A - Soil cultivating implements - Google Patents

Abstract

In a soil cultivating implement of the kind in which a row of soil working members 3 extends substantially horizontally perpendicular to the intended direction of operative travel A of the implement with each soil working member 3 rotatable about the upright axis of a corresponding shaft 2, and with a longitudinal element 14 located immediately in advance of carriers 4 of soil working tines 5 of said members, that element 14 co-operates with the members 3 in crumbling the soil and spreading it uniformly and, should a stone or other hard object become momentarily trapped between its lower rear surface and at least one of the carriers 4, said element 14 will be temporarily displaced substantially only upwards by the co-operation of sliders 13 with guide members 12 secured by supports 11 to a hollow frame portion 1 of the implement, such displacement being against the resilient opposition of springs 17. An alternative construction is described in which the element 14 is upwardly displaceably connected to the frame portion 1 by spring-loaded parallelogram linkages and further alternative is described in which the longitudinal element occupies a fixed position relative to the frame portion 1 but in which the rear surface of that element, that faces the carriers 4, is of convex shape and resilient formation. <IMAGE>

Description

SPECIFICATION Soil cultivating implements This invention relates to soil cultivating implements or machines, such as rotary harrows, of the kind which comprise 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 or machine with each soil working member power-rotatable about a substantially vertical, or at least upwardly extending, axis and exhibiting a carrier supporting at least one downwardly projecting soil working tool, and there being an elongate longitudinal element arranged in advance of the soil working members with respect to said direction of travel and at substantially the same horizontal level as that of the soil working member carriers, the implement or machine also comprising means which will allowthe longitudinal elementto be temporarily displaced from its normal operative position at any time during the use of the implement or machine. The term "implement(s) or machine(s)" is shortened to "implement(s)" alone throughout the remainder of this document for the sake of brevity.

In the use of implements of this known kind, the longitudinal element co-operates with the immediately following rotary soil working members in crumbling the soil to produce, for example, a good seedbed in which the well crumbled soil is uniformly distributed throughout the working width of the implement.The longitudinal element engages stones and other hard objects brought to the ground surface by the implement, or already lying upon that surface, and urges them downwardly into the soil, any stone or the like which nevertheless becomes momentarily jammed between the element and at least one rotating soil working member being prevented from causing damage to the element and/or to the carrier(s) and its/their tool(s) by virtue of the displacability of the element which allows it to move forwardly for a moment and facilitate release of the stone or the likewihout any bending or breakage of implement parts.

When working soil to a considerable depth, an accumulation of soil builds up in front of the longitudinal element and, with a known implement whose longitudinal element is displaceable substantially only forwardly in a more or less horizontal direction, this accumulation can severely restrict, or even completely prevent, such displacement, thus considerably reducing, if not eliminating, the antidamage protection offered by the longitudinal element. This can be a serious working disadvantage, particularly when the soil to be cultivated contains an above average quantity of stones.

An object of the invention is to allowthe longitudinal element to be displaced in a way which will give the required anti-damage protection without restriction even when the working conditions are such that an accumulation of soil is formed in advance of that element. According to one aspect of the invention, there is provided a soil cultivating implement of the kind set forth, wherein the longitudinal element is provided with guide members which allow it to be displaced from its normal operative position, during the use of the implement, in substantially only an upward direction.

According to a second aspect of the invention, there is provided a soil cultivating implement which comprises 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 soil working member power-rotatable about a substantially vertical, or at least upwardly extending, axis and exhibiting a carrier supporting at least one downwardly projecting soil working tool, and there being an elongate longitudinal element arranged in advance of the soil working members with respect to said direction of travel and at substantially the same horizontal level as that of the soil working member carriers, wherein the rear of the longitudinal element, which faces said soil working members, is of resilient formation.

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 somewhat diagrammatic plan view of a soil cultivating implement constructed in accordance with the invention, Figure 2 is a section, to an enlarged scale, taken on the line ll-ll in Figure 1, Figure 3 is a similar section to Figure 2 but illustrates an alternative embodiment, and Figure 4 is again a similar section to Figure 2 but illustrates a construction in accordance with the second aspect of the invention.

The soil cultivating implements which will be described, and that are illustrated in the accompanying drawings, are intended primarily, but not exclusively, for use in preparing seedbeds from previously worked soil in which seedbeds seeds can germinate and, after appropiate thinning of the seedlings, if required, can grow on to maturity. Referring now to Figures 1 and 2 of the accompanying drawings, the soil cultivating implement that is illustrated therein is in the form of a rotary harrow and comprises a hollow box-section frame portion 1 of elongate configuration whose longitudinal axis extends substantially horizontally transverse and usually, as illustrated, substantially horizontally perpendicular, 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 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 lie in a single row that is parallel to the transverse length of the hollow frame portion 1,the longitudinal axes/axes of rotation of the twelve shafts 2 being parallel to one another and being spaced apart at regular intervals which advantageously, but not essentially, each have a magnitude of substantially 25 cms. Each shaft 2 projects downwardly from beneath the bottom of the hollow frame portion 1 and is there provided with a coresponding soil working member that is generally indicated by the reference 3 (Figure 2).Each soil working member 3 comprises a substantially horizontally disposed support or carrier 4 defining arms that project in diametrically opposite directions from the shaft 2 concerned and whose outer ends have fastening portions of corresponding soil working tools in the form of rigid tines 5 firmly but releasably secured to them by means which includes corresponding pairs of bolts. The tines 5 have soil working portions which are of downwardly tapering formation and these portions project into the ground, when the implement is in use, to an extent that is adjustable in a manner which will be described below.

The opposite ends of the hollow frame portion 1 are closed by corresponding side plates 6 which extend substantially vertically parallel to one another and to the direction A. Upper leading portions of the two side plates 6 are provided with horizontally aligned pivots 7 about which respective arms 8 are upwardly and downwardlyturnable alongside said plates and against the surfaces of those plates 6 which face the centre of the implement. Each arm 8 extends generally rearwardly, with respect to the direction A, from the corresponding pivot and is of a downwardly and rearwardly offset construction (not visible in the drawings) towards the rear end thereof which projects well behind the frame portion 1 with respect to the direction A.

Substantially the rearmost and lowermost ends of the two arms 8 carry substantially horizontally aligned bearings in which stub shafts at the opposites ends of a ground roller 9 are received in a freely rotatable manner. The construction of the ground roller 9 is not the subject of the present invention but said roller is advantageously of cylindrical shape and an open-work, cage-like construction exhibiting a plurality of elongate rods that extend helically around the longitudinal axis of the roller 9 so as principally to define its skeletal ground-engaging surface. Rear portions ofthetwo side plates 6that project behind the remainder of the frame portion 1 with respect to the direction A are formed with curved rows of holes with the centre of curvature of each row coinciding with the substantially horizontal axis that is defined by the aligned pivots 7.Each arm 8 is formed with at least one hole at the same distance from that said axis and, upon bringing the holes, or chosen holes, in the arms 8 into register with chosen holes in the rear portions of the side plates 6 by turning the arms 8 upwardly or downwardly about the pivots 7, bolts 10 can be entered horizontally through the aligned holes and be tightened to retain the ground roller 9 at a corresponding bodily level relative to that of the frame portion 1 and rotary soil working members 3 as long as may be required. It will be realised that the implement bears upon the ground principally by way of the roller 9 so that it is this bodily level which is the major factor in determining the maximum depth of penetration of the tines 5 into the soil that is possible whilst the implement is in operation.

The front of the frame portion 1, with respect to the direction A, is provided at two locations with corresponding forwardly directed supports 11, said locations being mid-way between the second and third soil working members 3 counting from either end of the single row thereof when the implement is viewed in the direction A. That part of each support 11 which lies in advance of the front of the hollow frame portion 1 defines an upright guide member 12 that is vertically or substantially vertically disposed with a major portion of the length thereof extending downwardly from the part of the support 11 that is actually secured to the top of the hollow frame portion 1.Each guide member 12 is of U-shaped or channel-shaped cross section and is so disposed that the limbs of the U or channel project towards the centre of the implement from the base thereof which faces the neighbouring free end of the hollow frame portion 1. A slider 13 is arranged inside each guide member 12 so as to be readily movable upwardly and downwardly in that guide member without, however, being able readily to become detached therefrom. Each slider 13 projects downwardly from beneath the bottom of the corresponding guide member 12 and has its lower end welded or otherwise rigidly secured to a longitudinal element 14 that extends, as can be seen in Figure 1 of the drawings, throughout substantially the whole of the combined working width of the twelve, in the example that is being described, soil working members 3.The longitudinal element 14 may conveniently be in the form of a hollow beam of square (as illustrated) or other quadrilateral cross section that is so secured to the two sliders 13 that one diagonal of the square cross sectional is substantially vertical whilst the other diagonal thereof is substantially horizontal. As can be seen in Figure 2 of the drawings, the longitudinal element 14 is located at substantially the same horizontal level as are the carriers 4 of the twelve soil working members 3.

Each guide member 12 is internally provided, between its limbs, with a pin 15 on one end of which is secured to the top of the corresponding slider 13 and the opposite end of which projects upwardly through a plain hole in a stop plate 16 forming a horizontal top of the guide member 12 concerned. A helical compression spring 17 surrounds each pin 15 between the top of the coresponding slider 13 and the bottom of the corresponding plate 16 and thus tends to urge that slider 13 downwardly in the respective guide member 12. An upper portion of the length of each pin 15 is formed with a screw-thread and this screw-thread receives a co-operating nut and washer immediately above the corresponding stop plate 16wherethe pin 15 concerned projects upwardly through the plain hole in that stop plate.

The length of the sliders 13 is such that the springs 17 tend to maintain the longitudinal element 14 at substantially the level of the soil working member carriers 4 as shown in Figure 2 of the drawings but the nuts which co-operate with the upper ends of the pins 15 can be moved lengthwise of those pins 15 to some extent to increase or decrease the degree of compression of the springs 17 and raise or lower the element 14 relative to the frame portion 1 and soil working members 3. It will also be noted from Figure 2 of the drawings that, when the element 14 has the preferred shape and disposition that has been referred to above, a substantially horizontal digonal between its opposed corners is located at substantially the level of the tops of the twelve soil working member carriers 4.

The front of the hollow frame portion 1, with respect to the direction A, is provided with a coupling member or trestle 18 that is located mid-way between the general planes of the frame portion side plates 6 and that is of substantially isosceles triangular configuration as seen in front or rear elevation. The coupling member or trestle 18 defines two lower horizontally spaced apart coupling points for pivotal co-operation with the lower lifting links of a three-point lifting device or hitch carried by a tractor or other propelling and operating vehicle and also, at substantially its apex, a single upper coupling point for connection to the free end of the upper adjustable-length lifting link of the same lifting device or hitch.Downwardly and rearwardly divergent tie beams strengtheningly connected substantially the apex of the coupling member or trestle 18 to two widely spaced apart points at the top and rear of the hollow frame portion 1.

Each shaft 2 is provided, inside the hollow frame portion 1, with a corresponding straight- or spurtoothed pinion 19, the twelve (in this embodiment) pinions 19 being of such a size that the teeth of each such pinion 19 are in mesh with those of the or each immediately neighbouring pinion 19 in that 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 20 that is fastened in position immediately above the frame portion 1. Bevel pinions and shafts within the gear box 20 place this upward extension of one of the shafts 2 in driven connection with a substantially horizontal shaft that is parallel to the direction A and which has a splined or otherwise keyed leading end that projects forwardly from the front of the gear box 20 in that direction to enable it to be placed in driven connection with the power take-off shaft of an operating tractor or other vehicle (not shown) by way of a telescopic transmission shaft (also not shown) that is of a construction which is known per se having universal joints at its opposite ends.The rear of the gear box 20, with respect to the direction A, is provided with a change-speed gear 21 whose construction is not the subject of the presentinven- tion. It suffices to say that pairs of intermeshing toothed pinions of different sizes can be interchanged in the change-speed gear 21 or can be exchanged for co-operating pairs of other sizes, to vary the transmission ratio between the forwardly projecting rotary input shaft of the gear box 20 and the upward extension of said one of the shafts 2 from which all of the soil working members 3 are driven. This allows the soil working members 3 to be revolved at faster or slower speeds in response to a more or less standard speed of input rotation which is applied to the rotary input shaft of the gear box 20 when the implement is in use.

In the use of the soil cultivating implement that has been described with reference to Figures 1 and 2 of the drawings, its coupling member or trestle 18 is connected to the three-point lifting device or hitch at the rear of a n an agricultural tractor or other propelling and operating vehicle and, before work commences, the adjustments that may, if required, be made include raising or lowering the bodily level of the ground roller 9 relative to that of the soil working members 3 and altering the transmission ratio inside the change-speed gear 21 to increase or decrease the rate of revolution of the soil working members 3.

These adjustments will normally be made in the light of the nature and condition of the soil that is to be cultivated by the implement and the particular purpose for which that soil is required after the work has been completed. As the implement moves operatively in the direction A, the intermeshing relationship between the neighbouring pinions 19 ensures that each shaft 2, soil working member 3 and pinoin 19 will rotate in the opposite direction to the or each immediately neighbouring similar assembly.The distance between the two tines 5 of each soil working member 3 is either the same as, or a little greater than, the distance between the axes of rotation of immediately neighbouring shafts 2 so that, as a consequence, the twelve soil working members 3 will work overlapping, or at least adjoining, strips of ground that extend in the direction A thus producing a single broad strip of worked soil which, in the case of the embodiment that is being described, will have a width of substantially, although not necessarily exactly, 3 metres. It will be apparent that the working width of the implement could be increased or decreased by increasing or decreasing the number of rotary soil working members 3 in the single row thereof.

As the tines 5 move rapidly through the soil during advance of the implement in the direction A, streams of displaced soil are move forwardly by the tines 5, particularly where the tines 5 of two neighbouring soil working members are both moving forwardly relative to the direction A. Similarly, rearwardly moving streams of soil are produced, particularly where the tines 5 of two immediately neighbouring members 3 are both moving rearwardly with respect to the direction A. The soil tends to start breaking up immediately in advance of the soil working members 3 throughout all or most ofthe working width of the implement and, particularly when the tines 5 project deeply into the ground, a transverse accumulation of broken soil tends to build up just in fromt of those members 3 and as far forwardly therefrom as the bottom of the longitudinal element 14. This accumulation may also extend in front of the element 14 and is, of course, constantly being augmented by fresh soil and depleted by the removal of soil as the implement continues its advance, the tendency being for the volume of the accumulation to remain more or less comstant. The longitudinal element 14 and the soil working members 3 thus effectively co-operate with one another in a way which improves the degree of soil crumbling that is produced and that tends to improve the uniform spreading of the crumbled soil throughout the working width of the implement.

Any stones or other hard objects that may be brought to the soil surface by the tines 5 tend to encounter the leading surface of the element 14 that extends obliquely downwardly and rearwardly with respect to the direction A. This surface will, due to the continuing progress in the direction A, tend to push such stones or other hard objects downwardly beneath the surface of the worked soil.Stones and other hard objects thus rarely encounter the connections of the tines 5 to their carriers 4 so that damage from this cause is very significantly reduced, if not entirely eliminated, and it is very uncommon for for a stone or other hard object to become jammed between the contra-rotating carriers 4 of neighbouring soil working members 3, such jamming, ifthe stone or other hard object is not substantially immediately broken or otherwise released, being a potential cause of serious damage to the implement, and particularly the drive transmission to its soil working members 3.

It is possible for a stone or other hard object to find its way between at least one of the carriers 4 and the rear, relative to the direction A, of the longitudinal element 14. If this should momentarily occur, a force having at least a major forwardly directed compo next will be exerted upon the oblique lower rear surface of the longitudinal element 14 and this force will tend to deflect the element 14 substantially vertically upwards against the action of the corresponding compression spring or springs 17, the or each slider 13 moving upwardly in the corresponding guide member 12.The deflection of the longitudinal element 14 against the action of one or both of the springs 17 is sufficient to release the momentarily trapped stone or other hard object and, as soon as it no longer bears forcibly against the obliquely disposed lower rear surface of the element 14, the or each compressed spring 17 instantly restores sub stantiallythe position shown in Figure 2 of the drawings in which the upper rear edge of the lower rear surface of the element 14 is at substantially the same horizontal level as that of the tops of the soil working member carriers 4. Serious damage that is attributable to stones and other hard objects jammed between the rear of the element 14 and at least one of the rotating carriers 4 is thus substantially completely avoided.

Figure 3 illustrates an alternative construction in which the longitudinal element 14, that may be similar or identical in formation and disposition to the element 14 of Figures 1 and 2, is displacably connected to the hollow frame portion 1 by two parallelogram linkages 23 located at substantially the same positions as are the supports 11 shown in Figure 1 of the drawings. Each of the two substantially identical parallelogram linkages 23 comprises an upright support 25 fixedly secured to the top of the hollow frame portion 1 and a more or less vertically extending carrier 26 whose lower end is welded or otherwise rigidly secured to the upper leading surface of the longitudinal element 14.Upper and lower links 24 have their opposite ends turnably connected by substantially horizontal pivots to the corresponding support 25 and carrier 26, these pivots being at the four corners of a parallelogram as seen in Figure 3 of the drawings. A helical tension spring 28 bears between an anchorage on each upper link 24 and an anchorage that is substantially vertically therebeneath at the top and front of the hollow frame portion 1 with respect to the direction A.Each carrier 26 has a substantially horizontally disposed and rearwardly directed stop plate 27 welded or otherwise rigidly secured to it in such a position that the lower surface of said stop plate bears against the upper surface of the top of the hollow frame portion 1 where it will remain, under the action of the tension spring 28, unless a force sufficient resiliently to stretch the or each spring 28 is exerted upwardly on the or each carrier 26. It will be apparent from Figure 3 of the drawings that, when the stop plates 27 bear on the top of the hollow frame portion 1, the longitudinal element 14 is disposed immediately in front of the soil working member carriers 4 with the junction between its rear lower surface and its rear upper surface at substantially the same level as that of the tops of those carriers 4, the links 24 being horizontally disposed at such times.

If, when the construction of Figure 3 of the drawings is employed, a stone or other hard object should become momentarily jammed between the front of at least one rotating carrier 4 and the oblique lower rear surface of the element 14, a forwardly directed force will be exerted upon the element 14 by the jammed stone or other object and a component of this force will be sufficient to deflect one or both of the carriers 26 upwardly againstthe action of one or both of the springs 28, such displacement being substantially only a vertical one by virtue of the construction of the parallelogram linkages 23 that maintain a fixed angular disposition of each carrier 26 relative to the corresponding support 25 whatever the extent of the angular deflection of the corresponding links 24.In a similar manner to the first embodiment, the upward deflection of the element 14 allows the momentarily jammed stone or other hard object to be released whereupon the springs 28, or one of them, causelcauses the undeflected position illustrated in Figure 3 substantially immediately to be regained.

In either of the embodiments that have been described, the element 14 may have an angular cross-section other than square or it may be of circular or substantially circular cross section. In this latter case, a lower rear part (with respect to the direction A) of the convex surface of the longitudinal element will face generally downwardly and rearwardly and said element will be so positioned that the upper extremity of this part of its cylindrically curved convex surface will be at substantially the same horizontal level as that of the tops of the soil working member carriers 4.

Figure 4 of the drawings illustrates an embodiment in accordance with a second aspect of the invention, two supports 11Awhich occupy substantially the same positions as are shown for the supports 11 in Figure 1 being bolted or otherwise rigidly secured to the top of the hollow frame portion 1 so as to project a short distance forwardly therefrom in the direction A.A carrier 30 projects substantially vertically downwards from the forwardly projection portion of each support 11A and the lower ends of the carriers 30 are welded or otherwise rigidly secured to a longitudinal element 29 that is of L-shaped cross-section, being arranged with one limb of the L extending obliquely upwardly and rearwardly with respect to the direction A from the 90C junction between the limbs whilst the other limb, which is of greater length as seen in cross section, extends downwardly and rearwardly from the same junction with respect to the direction A.

The integrally interconnected limbs of the preferably metallic beam or bar that principally affords the longitudinal element 29 have a filling 31 of resilient material arranged between them in such a way that said filling 31 presents a cylindrically curved convex surface that faces rearwardly towards the carriers 4 of the soil working members 3, the lowermost extremity of the filling 31 being at substantially the same horizontal level as are the bottoms of the carriers 4 whilst the uppermost extremity of the filling 31 is at a level well above that of the tops of the same carriers 4.The resilient filling 31 may be natural or synthetic rubber bonded or otherwise adhesively secured to the limbs of the angular beam or bar that principally affords the element 29 or said filling 31 may be a foamed or solid synthetic plastics material of sufficient resilience and durability either bonded or adhesively secured to the limbs of the beam or bar. Other angular shapes of said beam or bar may, if preferred, be employed.

Should a stone or other hard object become momentarily jammed between at least one of the rotating carriers 4 and the cushion-like resilient filling 31, serious damage will almost always be avoided because the convex surface of the filling 31 will deform resiliently forwards until continued rotation of the or each affected carrier increases the distance between it and said filling 31 allowing that filling to regain its natural uncompressed shape and the momentarily jammed stone or other hard object to be released and fall downward into the soil being worked by the members 3. The convex surface of the filling 31 tends, it has been found, to facilitate the quick release of a momentarily jammed stone or other hard object.It is not essential that the rear surface of the element 29 that faces the soil working member carriers 4 should be in the form of the resilient filling 31 and some other resilient, or at least elastic, structure may, if preferred, be used as an alternative. Moreover, the rigid longitudinal element 14 of the embodiments of Figures 1 to 3 of the drawings may, if desired be replaced by the element 29 of Figure 4 of the drawings or by some other longitudinal element exhibiting a rearwardly directed resilient, or at least elastic, structure.

Although certain features of the implement embodiments that have been described and/or that are illustrated in the acompanying drawings will be set forth in the following claims as inventive features, 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 implement embodiment that has been described, and/or that is illustrated in the accompanying drawings, both individually and in various combinations.

Claims (19)

1. A soil cultivating implement of the kind set forth, wherein the longitudinal element is provided with guide members which allow it to be displaced from its normal operative position, during the use of the implement, in substantially only an upward direction.

2. An implement as claimed in claim 1, wherein, when the implement is disposed on flat horizontal ground, the displacability of the longitudinal element from its normal operative position that is allowed by the guide members is in substantially only a vertical direction.

3. An implement as claimed in claim 1 or 2, wherein the longitudinal element is displacable from its normal operative position against resilient opposition.

4. An implement as claimed in claim 3, wherein said guide members occupy fixed positions relative to a frame portion of the implement and each of them houses a corresponding slider which is fixed to the longitudinal element, said slider being upwardly displacable in the corresponding guide member against the opposition of a spring.

5. An implement as claimed in claim 4, wherein said spring is a compression spring arranged to bear between a stop plate of the corresponding guide member and a part of the respective slider.

6. An implement as claimed in claim 5, wherein said compression spring bears against the top of the corresponding slider.

7. An implement as claimed in any one of claims 1 to 3, wherein each guide member comprises at least one parallelogram linkage exhibiting pivotable links that lie one above the other and that are horizontally or substantially horizontally disposed when the longitudinal element occupies its normal operative position.

8. An implement as claimed in claim 7, wherein each parallelogram linkage tends to be maintained by a spring and a stop in the position in which its links are substantially horizontally disposed.

9. An implement as claimed in claim 7 or 8, wherein the guide members comprise two parallelogram linkages disposed in spaced apart relationship with one another.

10. An implement as claimed in any preceding claim, wherein the rear of the longitudinal element, with respect to the intended direction of operative travel of the implement, is of such a shape that said element will tend to be displaced upwardly when that rear has a displacing force exerted upon it.

11. An implement as claimed in claim 10, wherein said rear of the longitudinal element exhibits a part which is inclined downwardly and rearwardly with respect to the intended direction of operative travel of the implement.

12. An implement as claimed in claim 11, wherein the top of said part is located, when the element is in its normal operative position, at substantially the same horizontal level as are the tops of the carriers of said soil working members.

13. An implement as claimed in any preceding claim, wherein the longitudinal element is afforded by a profiled beam or bar of square, or at least quadrilateral, cross section, said beam or bar being so disposed that, in cross section, a line of connection between two corners thereof is substantially vertically disposed whereas a line connection between the other two corners is at substantially the same horizontal level as are the tops of the soil working member carriers when said longitudinal element is in its normal operative position.

14. An implement as claimed in any preceding claim, wherein the rear of the longitudinal element, which faces said soil working members, is of resilient formation.

15. A soil cultivating implement which comprises 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 soil working member power-rotatable about a substantially vertical, or at least upwardly extending, axis, and exhibiting a carrier supporting at least one downwardly projecting soil working tool, and there being an elongate longitudinal element arranged in advance of the soil working members with respect to said direction of travel and at substantially the same horizontal level as that of the soil working members, wherein the rear of the longitudinal element, which faces said soil working members, is of resilient formation.

16. An implement as claimed in claim 14 or 15 wherein the resilient formation of the rear of said longitudinal element is produced by providing resilient material at the rear of that element.

17. An implement as claimed in claim 16, wherein the resilient material exhibits a convex surface that faces the carriers of said soil working members.

18. An implement as claimed in any one of claims 14 to 17, wherein the longitudinal element comprises a beam or bar of L-shaped, or at least angular, cross section, and wherein a filling of resilient material is arranged between the limbs of said beam or bar to face rearwardly towards said soil working members.

19. A soil cultivating implement substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings, or Figures 1 and 3 of the accompanying drawings, or Figures 1 and 4 of the accompanying drawings.