GB1578944A - Soil cultivating implements - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO SOlL CULTIVATING IMPLEMENTS (71) We, C. VAN DER LELY N.V., of 10 Weverskade, Maasland, The Netherlands, a Dutch Limited Liability Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to soil cultivating implements of the kind that comprise a plurality of rotatably mounted soil working members each of which includes at least one tine having a portion fastened in a holder.

According to the invention, there is provided a soil cultivating implement of the kind set forth, where in each tine fastening portion is fixed in its appointed position by a key which co-operates with a flat formed on said fastening portion, the key being arranged in a bore which is located at that side of the corresponding holder which is closest to the axis of rotation of the soil working member of which said holder forms a part.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying drawings, in which: Figure 1 is a plan view of a soil cultivating implement in accordance with the invention connected to the rear of an agricultural tractor, Figure 2 is a section, to an enlarged scale, taken on the line II-II in Figure 1 Figure 3 is a section, to an enlarged scale, taken on the line IlI-III in Figure 2, Figure 4 is a part-sectional elevation as seen in the direction indicated by an arrow IV in Figure 3, Figure 5 is a side elevation as seen in the direction indicated by an arrow V in Figure 4, and Figure 6 is a part-sectional elevation, to the same scale as Figures 3 to 5, illustrating the construction and use of a tool that may advantageously be employed in removing tine fastening members or keys of the implement from their effective positions.

Referring to the accompanying drawings, the soil cultivating implement or machine that is illustrated somewhat diagrammatically in Figure 1 has a hollow boxsection frame portion I that extends substantially horizontally transverse, and usually substantially horizontally perpendicular, to the intended direction of operative travel of the implement which is indicated by an arrow A in the same Figure.

A plurality (in this case, twelve) of substantially vertical or at least non-horizontal shafts 2 are rotatably journalled in bearings carried by upper and lower walls of the hollow frame portion 1, the shafts 2 being arranged in a single transverse row with their longitudinal axes (axes of rotation) spaced apart from one another at regular intervals which preferably, but not essentially, have magnitudes of substantially 25 centimetres. Each shaft 2 projects downwardly from beneath the bottom of the hollow frame portion 1 and the downwardly projecting portion thereof is provided with a corresponding rotary soil working member that is generally indicated by the reference 3 and that will be further described below. Two shield plates 4 are arranged at short distances beyond the opposite ends of the single transverse row of the rotary soil working members 3, the two shield plates 4 usually being substantially vertically disposed in substantially parallel relationship with the direction A. Each shield plate 4 is connected by a pair of arms to pivotal mountings on the top of the hollow frame portion 1, said pivotal mountings defining an axis that extends substantially horizontally parallel to the direction A. The lower edge of each shield plate 4 is arranged for sliding movement over the ground surface in- the direction A, and in the opposite direction during manoeurving, and the pivotal connections of the plates 4 to the hollow frame portion 1 enable said plates to move upwardly and downwardly when the implement is in use to match un dulations in the surface of the ground over which the implement is travelling. The shield plies 4 co-operate with the adjacent soil working members 3 in cultivating the soil, minimise ridging of the soil at the opposite edges of the broad strip of land that is worked by the implement and act to prevent stones and other potentially injurious objects from being flung laterally of the path of travel of the implement by its rapidly rotating soil working members 3.

The opposite ends of the hollow frame portion 1 are closed by corresponding substantially vertical side plates 5 that are parallel to one another and substantially parallel to the direction A, each side plate 5 having a corresponding arm 6 arranged alongside it so as to be turnable upwardly and downwardly about the axis of a corresponding substantially horizontal pivot 6A which is located close to the front of the side plate 5 concerned with respect to the direction A. The arms 6 extend rearwardly from the corresponding, and aligned, pivots 6A alongside the respective plates 5 and project by some distance beyond the rearmost edges of those side plates 5. The side plates 5, also, project by short distances rearwardly beyond the remainder of the hollow frame portion 1 and, in the rearwardly projecting portions thereof, a plurality of holes are formed at equal distances from the axis defined by the aligned pivots 6A. Each arm 6 is formed with at least one hole at the same distance from said axis and that hole can be brought into register with any chosen one of the holes in the rearwardly projecting portion of the corresponding side plate 5 by turning the arm 6 concerned upwardly or downwardly about its pivot 6A. Horizontal locking pins 8 are provided for entry through the holes in the arms 6 and the chosen holes in the side plates 5 to retain said arms 6 in a corresponding angular position about the axis defined by the pivots 6A. Substantially horizontally disposed bolts may be employed in substitution for the locking pins 8. The rearmost ends of the two arms 6 carry substantially horizontally aligned bearings between which a rotatable supporting member of the implement in the form of an openwork ground roller 7 is rotatably mounted.

The particular angular positions of the arms 6 that are chosen about the axis defined by the pivots 6A determine the level of the axis of rotation of the roller 7 relative to that of the hollow frame portion 1 and thus the maximum depth to which the soil working members 3 of the implement that are carried by said frame portion 1 can penetrate into the ground when the implement is in use.

Each of the shafts 2 is provided, inside the hollow frame portion 1, with a corresponding straight-toothed or spur-toothed pinion 9, the size and arrangement of the pinions 9 being such that each of them has its teeth in mesh with those of its neighbour, or those of both of its neighbours, in the single row of pinions 9. Thus, each pinion 9, together with the corresponding shaft 2 and soil working member 3, will revolve, during the use of the implement, in a direction that is opposite to the direction of rotation of the or each immediately neighbouring assembly of parts 9, 2 and 3 (see the small arrows in Figure 1 of the drawings). One of the centre pair of shafts 2 in the row thereof has an upward extension through the top of the hollow frame portion 1 into a gear box 10 that Is mounted on top of the frame portion 1.

This shaft extension carries a bevel pinion that is in driven mesh with a further bevel pinion mounted on a substantially horizontal shaft (not visible) that extends substantially parallel to the direction A. The gear box 10 also comprises a second substantially horizontal rotary input shaft 12 that lies above the substantially horizontal shaft that has just been mentioned in parallel relationship therewith, the leading end of said shaft 12 projecting forwardly from the front of the gear box 10 in substantially the direction A. The rearmost end of the shaft 12 and the rearmost end of the underlying parallel shaft that is not visible in the drawings both project through the rear of the gear box 10 into a changespeed gear 11 that is mounted at the back of said gear box 10. The shaft ends that project into the change-speed gear 11 are both splined or otherwise keyed to receive the matchingly splined or keyed hubs of a pair of straight-toothed or spur-toothed pinions that is chosen from at least two co-operating pairs of such pinions which are of different sizes. The particular pair of pinions that is chosen, and the arrangement thereof which is employed with respect to the shaft ends that project into the changespeed gear 11, dictates the transmission ratio between the rotary input shaft 12 of the gear box ]0 and the underlying and parallel shaft and thus the speed at which all of the rotary soil working members 3 will be driven in response to a substantially constant input speed of rotation applied to the leading end of the shaft 12. As can be seen in Figure 1 of the drawings, the splined or otherwise keyed leading end of the shaft 12 is arranged to be placed in driven connection with the rear power take-off shaft of an agricultural tractor or other operating vehicle through the intermediary of a telescopic transmission shaft 13, that is of a construction which is known per se, having universal joints at its opposite ends. The front of the hollow frame portion 1 with respect to the direction A is provided, substantially midway between the planes of the side plates 5, with a coupling member or trestle 14 that is of substantially triangular configuration when seen in front or rear elevation. Locations that are close to the top of the coupling member or trestle 14 are connected by strengthening tie beams 15 to well spaced apart points at the top and rear of the frame portion 1 with respect to the direction A, said tie beams 15 diverging both downwardly and rearwardly from the coupling member or trestle 14 to the frame portion 1. The coupling member or trestle 14 is constructed and arranged for co-oeration with the rear threepoint lifting device or hitch of an agricultural tractor or other operating vehicle in the manner that is illustrated somewhat diagrammatically in Figure 1 of the drawings.

Figures 2 to 5 inclusive of the drawings illustrate the construction and arrangement of one of the rotary soil working members 3 in greater detail and it will be seen from those drawings that each member 3 comprises a horizontally or substantially horizontally disposed tine carrier or support 16 that is formed with a central internally splined hub whose splines co-operate with matching external splines on the downwardly projecting portion of the shaft 2 to which the member 3 concerned is to be secured, the lowermost extremity of said shaft 2 being formed as a short screwthreaded part which receives a washer and a nut that can be tightened to retain the hub in its appointed axial position on the shaft 2. A split pin or the like is preferably, as illustrated, provided to ensure that the nut will not work loose during the operation of the implement. The op posite ends of the tine carrier or support 16 that is illustrated in Figures 2 to 5 of the drawings are formed integrally with substantially cylindrical sleeve-like tine holders 17. Each holder 17 projects by a short distance above the top (disregarding the hub) of the carrier or support 16 with which it is integral and by a significantly greater distance downwardly beyond the bottom of that carrier or support. Each holder 17 has an axially extending internal bore of circular cross-section that is of constant diameter throughout its length and that is open at both its upper and lower ends. Each bore receives the cylindrical fastening portion 18 of a corresponding rigid soil working tine 19, the uppermost end of said portion 18 being substantially flush with the upper end of the holder 17 concerned. The lowermost end of each tine fastening portion 18 projects by a very short distance from beneath the lowermost end of the corresponding holder 17 and is then slightly narrowed so as integrally to join a soil working portion 20 of the same tine 19 which latter portion 20 projects downwardly into the soil when the implement is in use. Both the fastening portion 18 and the soil working portion 20 of each tine 19 are straight but it will be seen from Figures 3 and 5 of the drawings that the longitudinal axes of said two portions are inclined to one another at the junction between them by a small angle which preferably, but not essentially, has a magnitude of substantially 8 , the tines 19 being arranged, for most purposes (as illustrated), in such a way that the soil working portions 20 thereof are swept back rearwardly from top to bottom with re spect to the intended directions of operative rotation of the corresponding soil working members 3 so as to trail rearwardly relative to those directions.

The soil working portion 20 of each tine 19 commences, at its junction with the corresponding fastening portion 18, with a circular or substantially circular cross-section but, as one moves downwardly along said portion 20 towards the lowermost free end or tip thereof, the cross-section progressively changes in shape until a basically, but not truly, rhombic cross-section is achieved near the lowermost free end or tip of the portion 20 This basically rhombic cross-section is not, as will be seen in Figures 2, 4 and 5 of the drawings, anywhere near truly rhombic because the leading corner thereof with respect to and intended direction of operative rotation of the corresponding member 3 is shaped to provide a rib 21 whilst the two radially innermost and outermost corners (with respect to the axis of rotation a of the corresponding member 3) are formed as ribs 22 which have rounded edges. Moreover, the soil working portion 20 of each tine 19 is formed throughout substantially three quarters of its length, commencing from the lowermost free end or tip thereof, in each of the what would otherwise be four flat sides of the basically rhombic crosssection, with a concave groove 23. As seen in Figure 4 of the drawings, each tine portion 20 tapers downwardly towards its lowermost free end or tip whereas, as seen in Figure 5 of the drawings, there is only a slight downward taper which is very much less pronounced than when viewed in Figure 4.

The fastening portion 18 of each tine 19 is formed, just above the middle of its length, with two diametrically opposed recesses 24 each of which defines a corresponding internal flat 25. Each flat 25 has a length in a direction that is parallel to the length of the corresponding tine fastening portion 18 which is equal to substantially one quarter of the length of that portion 18 and, as viewed lengthwise of the longitudinal axis of each tine fastening portion 18 (Figure 3), each flat 25 subtends an angle of substantially 60 at that axis. Each flat 25 is arranged to cooperate with a bevelled flat 25A on a corresponding fastening key in the form of a basically cylindrical cotter pin 26. Each holder 17 is formed with a cylindrical bore 27 that extends perpendicular to the longitudinal axis (axis of rotation) a of the corresponding shaft 2 in tangential relationship with an imaginary circle centred upon that axis a. Each bore 27 is at that side of the corresponding holder 17 which is closest to the axis of rotation a of the soil working member 3 concerned. As can be seen in the drawings, the bores 27 open laterally into the central bores of the holders 17 that receive the tine fastening portions 18 at locations which register with the recesses 24 in those portions 18.

Each cotter pin 26 is formed at one end with a screwthreaded portion 28 of reduced diameter and that portion 28 receives a washer 29 and a fastening nut 30 which will maintain the cotter pin 26 concerned in its appointed fastening position after said pin 26 has been tapped into that position by a hammer or the like and the nut 30 has been tightened by a spanner or wrench. The co-operation between the bevelled flat 25A of each cotter pin 26 that protrudes from the corresponding bore 27 into the central bore of the associated holder 17 and the flat 25 in the adjoining recess 24 of the tine fastening portion 18 that is lodged in said central bore of the holder 17 very firmly and effectively secures the tine fastening portion 18 in its holder 17 once the cotter pin 26 concerned has been urged fully home into the cooperating bore 27 and the nut 30 has been fully tightened. Parallel planes which contain the two flats 25 of the two recesses 24 in each of the tine fastening portions 18 are inclined at substantially 5 to a plane that contains the longitudinal axis of that fastening portion and also the longitudinal axis of the corresponding soil working portion 20. Similarly, the general plane of the bevelled flat 25A on each cotter pin 26 is inclined at substantially 5 to a plane which contains the longitudinal axis b of the bore 27 in which said cotter pin is disposed, the latter plane being parallel to the longitudinal axis a of the associated shaft 2. The two bores 27 of each soil working member 3 are, of course, disposed with their longitudinal axes b in perpendicular relationship with the longitudi- nal axis of the associated shaft 2 and both of said axes b are thus tangential to an imaginary circle centred upon said axis a.

The screwthreaded portion 28 of each cotter pin 26, together with tie respective washer 29 and fastening nut 30, are located at the rear of the corresponding holder 17 with respect to the intended direction of operative rotation of the soil working member 3 of which said holder 17 forms a part (see the arrow in Figure 3 of the drawings) and protection of these parts against damage by direct collisions with stones and other articles and excessive wear by abrasive soiling and the like is thus ensured. The fastening portion 18 of each tine 19 has two diametrically opposed recesses 24 and, whilst the tines 19 will usually be mounted in the illustrated positions in which their soil working portions 20 trail with respect to the intended directions of operative rotation of the soil working members 3 as discussed above, it may sometimes be desirable for them to be mounted in positions in which the soil working portions 20 are inclined forwardly from top to bottom so as to lead with respect to said directions of rotation.

Such positions are desirable for use in, for example, cultivation work on a stubble field. It will be apparent that it is only necessary temporarily to release the cotter pins 26, to turn the tines 19 through 1800 about the longitudinal axes of their fastening portions 18 and to re-engage the cotter pins 26 to bring them to these alternative working positions, the bevelled flats 25A on the cotter pins 26 then co-operating with the opposite flats 25 in the second recesses 24 of the cylindrical fastening portions 18.

In the use of the soil cultivating implement that has been described, its coupling member or trestle 14 is connected to the three-point lifting device or hitch at the rear of an agricultural tractor in the manner shown in outline in Figure 1 of the drawings and the rotary input shaft 12 of the gear box 11 is placed in driven connection with the rear power take-olf shaft of the same agricultural tractor or other operating vehicle through the intermediary of the known telescopic transmission shaft 13 that has universal joints at its opposite ends. Adjustments that may be necessary before work commences include setting the maximum depth to which he tines 19 of the soil working members , can penetrate into the soil by adjusting the level of the axis of rotation of the rolier 7 upwardly or downwardly relat;ve to the level of the hollow frame portion 1 employing the arms 6 and the locking pins or equivalent bolts in the manner that has been described above and setting the speed at which the soil working members 3 will revolve in response to a more or less constant speed of rotation applied to the input shaft 12 of the gear box 10 by an adjustment in the change-speed gear 11.

These adjustments will usually be made having regard to the nature and condition of the soil that is to be worked and the particular purpose for which that soil is required after cultivation. As the implement is moved operatively in the direction A by an agricultural tractor or other vehicle, drive applied to the rotary input shaft 12 of the gear box 10 causes the shafts 2 and soil working members 3 to revolve in the opposite directions that are indicated by the small arrows in Figure 1 of the drawings and, since each soil working member 3 has an effective working width which is a little greater than the spacing between the axes a of immediately neighbouring shafts 2 (preferably substantially 25 centimetres), the strips of land that are worked b) the individual members 3 overlap one another to form a single broad strip of worked soil that will have a width of substantially 3 metres in the case of the example that is being described when the preferred spacing between the longitudinal axes a is employed. The shield plates 4 occupy substantially the positions illustrated in Figure 1 of the drawings at this time and spaced elongate ele ments (not shown) at the circumference of the open ground roller 7 act to crush any lumps of soil that may be left upon the ground surface by the tines 19 of the foregoing soil working members, to level that worked soil and to distribute the latter evenly throughout the working width of the implement, these functions of the roller 7 being additional to its primary function as as rotatable supporting member of the implement. The formation of the tines 19 that has been described and illustrated enables said tines to be manufactured in a simple manner and the fastening of the tines in their operative positions that has been described and that is illustrated in the accompanying drawings enables said tines to be retained in those positions in a very reliable manner. Known fastening constructions and arrangements for tines in implements of the kind that is set forth at the beginning of this specification are, generally speaking, quite effective but do suffer from the disadvantage that the manufacturing cost is somewhat high. Moreover, when subject to very heavy stresses under adverse working conditions, the known fastening arrangements have shown some tendency to failure, the tines or like tools becoming loose during operation.

The present invention provides simple and inexpensive fastening arrangements for the tines 19 which arrangements avoid, or at least very significantly reduce, the tendency to invoiuntary loosening under adverse working conditions or other circumstances of heavy stress. The fastening keys that are afforded by the cotter pins 26 in the example that has been described do not project from the bores 27 at the leading ends of those bores with respect to the intended directions of operative rotation of the corresponding soil working members 3 and, when one of said cotter pins 26 is to be removed from its bore 27, an extractor tool 31 that is illustrated in Figure 6 of the drawings may advantageously be employed to facilitate such removal. The nut 30 and washer 29 are first removed by employing a spanner or wrench with a pre-treatment by a wire brush and/or penetrating oil if this seems to be necessary. The extractor tool 31 comprises an arched bracket 32 which will embrace the tine holder 17 corresponding to the bore 27 in which is situated the cotter pin 26 that is to be removed.

One limb of the bracket 32 is formed with a circular hole 33 whose diameter is greater than that of each bore 27 whilst the other opposed limb of the bracket 32 is extended to form a sleeve 34 whose longitudinal axis is aligned with the centre of the hole 33, the internal bore of the sleeve 34 being screwthreaded. Pressing means in the form of a matchingly screwthreaded bolt 35 is entered in the bore of the sleeve 34 with its shank projecting therefrom towards the hole 33.

The shank of the bolt 35 is formed with a cylindrical recess 36 that extends axially into the shank from an open end thereof which is remote from the head of the bolt 35, the diameter of the recess 36 being such that it will receive the screwthreaded portion 28 of the cotter pin 26 that is to be removed therein, the mouth of the recess 36 bearing against the shoulder that is formed between the portion 28 of the cotter pin 26 and the main larger diameter body thereof. Once the washer 29 and nut 30 have been removed and the tool 31 has been arranged as shown in Figure 6 of the drawings, it is only necessary progressively to screw the bolt 35 into the sleeve 34 to force the cotter pin 26 axially out of the co-operating bore 27 through the hole 33 in the limb of the tool bracket 32 that is remote from the limb thereof that comprises the sleeve 34.

WHAT WE CLAIM IS: - 1. A soil cultivating implement of the kind set forth, wherein each tine fastening portion is fixed in its appointed position by a key which co-operates with a flat formed on said fastening portion, the key being arranged in a bore which is located at that side of the corresponding holder which is

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

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. revolve in response to a more or less constant speed of rotation applied to the input shaft 12 of the gear box 10 by an adjustment in the change-speed gear 11. These adjustments will usually be made having regard to the nature and condition of the soil that is to be worked and the particular purpose for which that soil is required after cultivation. As the implement is moved operatively in the direction A by an agricultural tractor or other vehicle, drive applied to the rotary input shaft 12 of the gear box 10 causes the shafts 2 and soil working members 3 to revolve in the opposite directions that are indicated by the small arrows in Figure 1 of the drawings and, since each soil working member 3 has an effective working width which is a little greater than the spacing between the axes a of immediately neighbouring shafts 2 (preferably substantially 25 centimetres), the strips of land that are worked b) the individual members 3 overlap one another to form a single broad strip of worked soil that will have a width of substantially 3 metres in the case of the example that is being described when the preferred spacing between the longitudinal axes a is employed. The shield plates 4 occupy substantially the positions illustrated in Figure 1 of the drawings at this time and spaced elongate ele ments (not shown) at the circumference of the open ground roller 7 act to crush any lumps of soil that may be left upon the ground surface by the tines 19 of the foregoing soil working members, to level that worked soil and to distribute the latter evenly throughout the working width of the implement, these functions of the roller 7 being additional to its primary function as as rotatable supporting member of the implement. The formation of the tines 19 that has been described and illustrated enables said tines to be manufactured in a simple manner and the fastening of the tines in their operative positions that has been described and that is illustrated in the accompanying drawings enables said tines to be retained in those positions in a very reliable manner. Known fastening constructions and arrangements for tines in implements of the kind that is set forth at the beginning of this specification are, generally speaking, quite effective but do suffer from the disadvantage that the manufacturing cost is somewhat high. Moreover, when subject to very heavy stresses under adverse working conditions, the known fastening arrangements have shown some tendency to failure, the tines or like tools becoming loose during operation. The present invention provides simple and inexpensive fastening arrangements for the tines 19 which arrangements avoid, or at least very significantly reduce, the tendency to invoiuntary loosening under adverse working conditions or other circumstances of heavy stress. The fastening keys that are afforded by the cotter pins 26 in the example that has been described do not project from the bores 27 at the leading ends of those bores with respect to the intended directions of operative rotation of the corresponding soil working members 3 and, when one of said cotter pins 26 is to be removed from its bore 27, an extractor tool 31 that is illustrated in Figure 6 of the drawings may advantageously be employed to facilitate such removal. The nut 30 and washer 29 are first removed by employing a spanner or wrench with a pre-treatment by a wire brush and/or penetrating oil if this seems to be necessary. The extractor tool 31 comprises an arched bracket 32 which will embrace the tine holder 17 corresponding to the bore 27 in which is situated the cotter pin 26 that is to be removed. One limb of the bracket 32 is formed with a circular hole 33 whose diameter is greater than that of each bore 27 whilst the other opposed limb of the bracket 32 is extended to form a sleeve 34 whose longitudinal axis is aligned with the centre of the hole 33, the internal bore of the sleeve 34 being screwthreaded. Pressing means in the form of a matchingly screwthreaded bolt 35 is entered in the bore of the sleeve 34 with its shank projecting therefrom towards the hole 33. The shank of the bolt 35 is formed with a cylindrical recess 36 that extends axially into the shank from an open end thereof which is remote from the head of the bolt 35, the diameter of the recess 36 being such that it will receive the screwthreaded portion 28 of the cotter pin 26 that is to be removed therein, the mouth of the recess 36 bearing against the shoulder that is formed between the portion 28 of the cotter pin 26 and the main larger diameter body thereof. Once the washer 29 and nut 30 have been removed and the tool 31 has been arranged as shown in Figure 6 of the drawings, it is only necessary progressively to screw the bolt 35 into the sleeve 34 to force the cotter pin 26 axially out of the co-operating bore 27 through the hole 33 in the limb of the tool bracket 32 that is remote from the limb thereof that comprises the sleeve 34. WHAT WE CLAIM IS: -

1. A soil cultivating implement of the kind set forth, wherein each tine fastening portion is fixed in its appointed position by a key which co-operates with a flat formed on said fastening portion, the key being arranged in a bore which is located at that side of the corresponding holder which is

closest to the axis of rotation of the soil working member of which said holder forms a part.

2. An implement as claimed in claim 1, wherein each tine fastening portion is formed with at least one recess which defines said flat that is arranged to cooperate with said key.

3. An implement as claimed in claim 2, wherein each tine fastening portion has the corresponding recess formed substantially along its axial length.

4. An implement as claimed in claim 3, wherein each recess is closer to the free end of the corresponding tine fastening portion than it is to a junction of that portion with a soil working portion of the same tine.

5. An implement as claimed in any one of claims 2 to 4, wherein the flat that is defined by each recess has a width, measured in a direction parallel to the axial length of the corresponding tine fastening portion, which is equal to substantially one quarter of that axial length.

6. An implement as claimed in any preceding claim, wherein the flat on each tine fastening portion is inclined at an angle of substantially 5 to a plane containing the longitudinal axis of said fastening portion and also the longitudinal axis of a soil working portion of the same tine, said two portions of the tine being in inclined relationship.

7. An implement as claimed in claim 2 or in any one of claims 3 to 6 when read as appendant to claim 2, wherein each tine fastening portion is formed with two diametrically opposed recesses, the flats that are defined by said two recesses being in parallel or substantially parallel relationship with one another.

8. An implement as claimed in any preceding claim, wherein the or each flat on each tine fastening portion subtends an angle of substantially 60 at the longitudinal axis of that fastening portion.

9. An implement as claimed in any preceding claim, wherein the longitudinal axis of each bore is in tangential relationship with a circle centred upon the axis of rotation of the corresponding soil working member.

10. An implement as claimed in any preceding claim, wherein each key has a bevelled flat that is arranged to co-operate with the flat or one of the flats on the corresponding tine fastening portion.

11. An implement as claimed in claim 10, wherein the bevelled flat of each key is inclined to a plane containing the longitudinal axis of that key at an angle of substantially 5".

12. An implement as claimed in any preceding claim, wherein the diameter of each key is substantially the same as the diameter of each of said bores.

13. An implement as claimed in any preceding claim, wherein, when each tine is fixed in its appointed position, the top of the fastening portion thereof is substantially flush with the top of the corresponding holder.

14. A soil cultivating implement of the kind set forth substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.