GB2133262A - Soil cultivating implements - Google Patents

Abstract

In a soil cultivating implement, such as a rotary harrow, of the kind which comprises a hollow frame portion 1 extending substantially horizontally perpendicular to the intended direction of operative travel of the implement and a plurality of soil working members supported thereby so as to be rotatable about the axes of corresponding substantially vertical shafts, each member comprises at least one straight tine 13 formed from rod material and a circular cylindrical fastening portion 12 which is received in the hollow interior of a holder 10 where it is fastened by a headed wedge 15 of straight configuration that extends parallel or substantially parallel to the longitudinal axis of the tine 13 in aligned recesses formed in upper rear regions of said fastening portion 12 and the holder 10. Each time 13 also comprises a soil working portion 14 having front and rear ribs, with respect to the intended direction of operative rotation B of the corresponding soil working member, the upper ends of said ribs bearing against the lower end of the corresponding holder 10. <IMAGE>

Description

SPECIFICATION Soil cultivating implements This invention relates to soil cultivating implements or machines, such as rotary harrows intended for the preparation of seedbeds, of the kind which comprises a frame portion movable over the ground and a plurality of soil working members that are rotatable about substantially vertical, or at least upwardly extending, axes, each such member including a carrier to which at least one soil working tool is connected by way of a corresponding holder.

An object of the present invention is to be able to secure the soil working tools, such as tines, of implements of the kind set forth in their holders in a particularly simple, reliable and inexpensive manner. Accordingiy, the present invention provides a soil cultivating implement of the kind set forth, wherein each soil working tool is fixed in its holder by a wedge that extends parallel or substantially parallel to the longitudinal axis or centre line of that tool.

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 in accordance with the invention shown connected to the rear of an agricultural tractor, Figure 2 is a part-sectional view, to an enlarged scale, the section being taken on the line 11-11 in Figure 1, and Figure 3 is an elevation as seen in the direction indicated by an arrow Ill in Figure 2.

Referring to the accompanying drawings, the soil cultivating implement that is illustrated therein is in the form of a rotary harrow and comprises an elongate hollow frame portion 1 that extends substantially horizontally transverse and usually, as illustrated, substantially horizontally perpendicular, to the intended direction of operative travel of the implement that is indicated in Figure 1 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 cm. Each shaft 2 projects downwardly from beneath the bottom of the hollow frame portion 1 and is there provided with a corresponding 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 having two arm-like portions 5 that project in substantially diametrically opposite directions from a central hub 6 of the carrier which hub 6 has internal splines arranged to co-operate with matching external splines on a downwardly projecting portion of the corresponding shaft 2 to prevent the carrier and the shaft from being rotationally displaceable relative to one another.

Axial displacement of each carrier 4 relative to the corresponding shaft 2 is prevented in a known manner that is not the subject of the present invention but which includes providing a screwthreaded lowermost end portion of each shaft 2 with a co-operating retaining nut that, when installed, is prevented from becoming loose by the provision of a split pin or the like entered through a transverse bore in the screw-threaded shaft portion and through aligned openings in the nut itself.

Each substantially horizontally extending armlike portion 5 has a flat lower surface whereas the top thereof is provided with a substantially central upright rib 7 which extends lengthwise of the portion 5 concerned from the hub 6 to the outer end of that portion, each rib 7 being substantially regularly tapered, as seen in plan view and as is visible in Figure 3 of the drawings, from the hub 6 concerned to the outer end of the portion 5 above which it lies. Each rib 7 also decreases in its vertical extent considered from the hub 6 concerned to the outer end thereof and this feature can be seen best in Figure 2 of the drawings from which it will also be apparent that each rib 7 is rounded off at its radially outermost end so that the upper surface thereof meets the top of the corresponding portion 5 at the radially outer end of that portion 5.Each portion 5 is formed, at opposite sides of the corresponding rib 7, with a hole through which the shank of a corresponding bolt 8 is entered (preferably upwardly, as illustrated) to secure a fastening portion 9 of a corresponding tine holder 10 to the arm-like portion 5 concerned. The upper ends of the two bolts 8 of each pair are, of course, provided with corresponding fastening nuts and may also carry washers or the like (not shown) designed to prevent the bolts 8 from working loose during the operation of the implement. The outward taper of each rib 7, and particularly the rounding off of the radially outer end thereof, tends to facilitate ready disengagement of temporarily adhering weeds, root remnants and the like.

The two arm-like portions 5 of each carrier 4 are each provided at the front thereof, with respect to the intended direction of operative rotation B (Figures 1 and 3) of the soil working member 3 concerned, with an upwardly and forwardly (relative to same direction B) inclined shield 5A. The shields 5A lie in advance of the nuts which co-operate with the bolts 8, with respect to the direction B, and thus tend to protect those nuts from direct collisions with potentially damaging stones and other hard objects. Any such stone or other hard object encountered by the oblique leading surface, relative to the direction B, of any shield 5A tends to be pushed downwardly into the soil that is being worked by the implement.The fastening portion 9 of each tine holder 10 has a flat upper surface which abuts against the flat lower surface of the corresponding arm-like portion 5 throughout a relatively large area of contact and the radially inner flat end of each fastening portion 9 bears against a matching flat on an otherwise substantially cylindrical portion of the hub 6 concerned. It will be realised that this portion of each hub 6 thus has two diametricaily opposed flats whose surfaces contact the inner ends of the corresponding fastening portions 9, each such contact surface being in substantially tangential relationship with an imaginary cylindrical surface whose longitudinal axis coincides with the longitudinal axis of the respective shaft 2.

The lower surface of each fastening portion 9 is provided with a corresponding centrally positioned rib 11 that extends radially with respect to the longitudinal axis of the corresponding shaft 2, said rib 11 lying between the heads of the corresponding pair of fastening bolts 8. The radially outermost end of each rib 11 is integrally or rigidly secured to the corresponding tine holder 10 at substantially the top of that tine holder.

Although being of sleeve-like formation, each tine holder 10 is of angular shape having front and rear surfaces, with respect to the intended direction of operative rotation B of the corresponding soil working member 3, that are inclined generally downwardly and rearwardly relative to that direction B, the radially outer edges of the front and rear surfaces meeting an angular outer side surface whose shape can be seen in Figure 3. The top of each tine holder 10 is substantially flat but is inclined downwardly and outwardly with respect to the corresponding shaft 2 away from its angularjunction with the outer end of the corresponding fastening portion 9.This construction provides increased clearance between immediately neighbouring soil working members 3 of the implement when it is in use and thus enables stones and other hard objects to pass between the members 3 with a reduced risk of damage to those members.

The hollow interior of each sleeve-like tine holder 10 receives a fastening portion 1 2 of a corresponding soil working tool in the form of a tine 1 3. The axial length of this hollow interior may advantageously have a magnitude of substantially 80 mm. It will be seen from Figure 2 of the drawings that each tine 13 is formed from a length of metallic rod that is of basically circular cross-section but a lower soil working portion 14 of which also defines two diametrically opposed ribs that lie at the front and rear of each tine with respect to the intended direction of operative rotation B of the corresponding soil working member 3.The ribs of the soil working portions 14 enhance the soil crumbling action of the tines 13 and it will be seen from Figures 2 and 3 of the drawings that the upper ends of each pair of ribs abut against the lower end of the corresponding tine holder 10. Each tine 1 3 is straight throughout its length, and the hollow interior of each holder 10, and thus the longitudinal axis of any tine 13 whose fastening portion 12 is installed in that holder 10, trails rearwardly with respect to the corresponding direction B (see Figure 3). The opposite ends of each tine 1 3 are perpendicular to the longitudinal axis of the tine and the rod material from which the tines 13 are formed advantageously has a diameter of substantially 22 mm in the example that is being described, excluding the ribs exhibited by the soil working portions 14 of the tines.

Each tine 13 is retained in the operative position that is illustrated for one of them in Figures 2 and 3 of the drawings by the use of a corresponding wedge 1 5 that, when installed, is entered into aligned axially extending recesses formed in the upper end of the fastening portion 12 of the tine 13 concerned and in the upper end of the hollow interior of the co-operating tine holder 10 (see Figure 3), the aligned recesses being at the rear of the tine 1 3 and its holder 10 with respect to the corresponding direction B.The aligned recesses are straight and extend parallel to the axial length of the tine holder 10 and the installed tine 13 and each wedge 1 5 has an axial length which is substantially equal to half that of the hollow interior of the tine holder 10 and thus, in the embodiment that is being described, it advantageously has an axial length of substantially 40 mm. As seen in Figure 3 of the drawings, the illustrated wedge 1 5 has a leading edge which is parallel to the lengths of the aligned recesses but the rear edge of which is very gently inclined to the leading edge in a downwardly tapering direction.The upper end of each wedge 1 5 is provided with a head that is too large to enter the aligned recesses and which therefore, when the tine 13 concerned is installed in its holder 10, stands proud of the inclined upper surface of that holder together with a short length of the fastening portion 12 of said tine 13. Each wedge 1 5 co-operates with both of the aligned recesses in the corresponding tine fastening portion 1 2 and tine holder 10 and thus prevents the tine 1 3 from turning about its own longitudinal axis in the holder 10.The wedge 1 5 is located in an upper rear region of the tine fastening portion 1 2, with respect to the direction B, and it will be apparent that, in this region, said fastening portion 12 exerts only a relatively low pressure upon the tine holder 10 as the soil working portion 14 of the same tine moves through the soil in the direction B. The inclination of each installed tine 13 to a plane containing the longitudinal axis of the corresponding shaft 2 and a point on the longitudinal axis of the straight tine 13 concerned is preferably not less than substantially 8 and not more than substantially 100 and it will be noted from Figure 3 of the drawings that each holder 10 comprises more material at the front thereof, with respect to the direction B, that it does at the rear thereof since the holders 10, as well as the tines 13, inevitably suffer wear during operation which wear is much more marked at the front, in the direction of operative rotation, than it is at the rear.

The opposite ends of the hollow frame portion 1 are closed by corresponding side plates 1 6 (Figure 1) which are substantially vertically parallel to one another and to the direction A. The fronts of the side plates 16, with respect to the direction A, carry substantially horizontally aligned pivot bolts or other strong pivots 1 7 about which arms 1 7A are upwardly and downwardly turnable alongside the plates 1 6. The arms 1 7A extend rearwardly from the pivots 1 7 with respect to the direction A and their rearmost ends lie well behind the hollow frame portion 1 considered in the direction A.The rearmost ends of the two arms 1 7A carry substantially horizontal bearings in which the opposite ends of an open-work cage-formation ground roller 1 8 are rotatably journalled. The angular positions of the arms 1 7A about the axis defined by the pivots 1 7 can be changed, as may be required, by entering retaining members, such as bolts 19, in holes in the arms 1 7A themselves and chosen aligned holes in curved rows thereof that are formed in rear portions of the side plates 1 6 which project behind the frame portion 1 with respect to the direction A, the centres of curvature of these curved rows of holes being coincident with the axis defined by the pivots 1 7. The holes that are chosen for co-operation with the bolts 1 9 or the like determine the level of the axis of rotation of the ground roller 1 8 relative to that of the frame portion 1 and the single row of soil working members 3 and thus the maximum depth to which the tines 1 3 of those soil working members 3 can penetrate into the ground when the implement is in use.The construction of the ground roller 1 8 is not the subject of the present invention but it will be seen from Figure 1 of the drawings that it comprises a central preferably tubular shaft to which a plurality of regularly spaced apart support plates are secured so as to be parallel to one another and substantially parallel to the direction A.Elongate elements of tubular or solid rod formation are entered through regularly spaced apart holes around the edges of the preferably circular support plates of the roller 18 and preferably, as illustrated, extend helically around the axis of rotation of that roller to define skeletally a cylindrical ground-engaging surface so that, during use of the implement, the roller 18 will act in its own right as a soil working member which will crush any stubborn lumps or clods of earth that have resisted crumbling by the immediately foregoing soil working members 3 as well as performing a gentle levelling and consolidating action upon the ground surface.

Each shaft 2 is provided, inside the hollow frame portion 1 with a corresponding straight- or spur-toothed pinion 20 which is of such a size that its teeth are in mesh with those of the or each immediately neighbouring pinion 20 in the single row thereof. The shaft 2 which corresponds to one of the centre pair of soil working members 3 in the single row thereof has an upward extension through the top or cover plate of the hollow frame portion 1 into a gear box 21 that is mounted on top of said frame portion 1.Shafts and bevel pinions (not visible) inside the gear box 21 place the upward extension of the shaft 2 that has just been mentioned in driven connection with a rotary input shaft 23 of the gear box 21 whose leading splined or otherwise keyed end projects substantially horizontally forwards from the front of the gear box in substantially the direction A where it can be connected to the rear power takeoff shaft of an agricultural tractor or other operating vehicle by way of a telescopic transmission shaft 24, which is of a construction that is known per se, having universal joints at its opposite ends. The back of the gear box 21, with respect to the direction A, is provided with a change-speed gear 22 whose construction is not the subject of the present invention.It suffices to say that the splined ends of two shafts project into the casing of the change-speed gear 22 and can co-operate with the internally splined hubs of co-operating pairs of toothed pinions of different sizes. These pairs of pinions can be interchanged, or be exchanged for other pairs, to give different transmission ratios and thus allow the speed of rotation of the soil working members 3 to be increased or decreased in response to substantially the same speed of driving rotation that is applied to the rotary input shaft 23 of the gear box 21.The front of the hollow frame portion 1, with respect to the direction A, is provided with a coupling member or trestle 25 at a location substantially mid-way between the two frame portion side plates 16, said coupling member or trestle 25 being of approximately triangular configuration as seen in either front or rear elevation and being constructed for co-operation with the upper and lower lifting links of a threepoint lifting device or hitch mounted at the rear of the agricultural tractor or other vehicle which both moves and operates the implement when the latter is in use.

In the use of the soil cultivating implement that has been described, the coupling member or trestle 25 is connected to the lifting links of the three-point lifting device or hitch at the rear of the agricultural tractor or other vehicle which both moves and operates the implement and the rotary input shaft 23 of the gear box 21 is placed in driven connection with the rear power take-off shaft of the same tractor or other vehicle by way of the known telescopic transmission shaft 24 which has universal joints at its opposite ends. The speed at which the soil working members 3 will revolve in response to a predetermined speed of driving rotation applied to the input shaft 23 is increased or decreased, if necessary, before work commences by an appropriate adjustment of the change-speed gear 22. Similarly, the maximum depth to which the tines 1 3 can penetrate into the ground is increased or decreased, if required, by changing the bodily level of the ground roller 18 relative to that of the frame portion 1 and soil working members 3. The implement which is being described is intended primarily for use in preparing seedbeds from previously worked soil in which seedbeds seeds can germinate and, after appropriate thinning of the seedlings, if required, can grow on to maturity. The adjustments indicated will normally be made in the light of the nature and condition of the soil that is to be cultivated and the particular purpose for which that soil is required after treatment by the implement.As the implement moves operatively over the ground in the direction A, each oinion 20, shaft 2 and soil working member 3 will revolve in the direction B which direction is opposite to that of the or each immediately neighbouring similar assembly in the single row of twelve, in this embodiment, such assemblies. Each soil working member 3 works an individual strip of ground whose width is equal to, or a little greater than, 25 cm so that these individual strips of ground overlap or at least adjoin one another to produce a single broad strip of worked soil that will have a width of substantially, although not necessarily exactly, 3 metres when there are twelve of the soil working members 3. It will readily be apparent that greater or smaller working widths are possible by increasing or decreasing the number of rotary soil working members 3.The soil working portions 14 of the tines 13 move very rapidly through the soil and provide a well crumbled homogeneous seedbed and any stubborn lumps or clods of soil that remain unbroken by the tines 1 3 are usually crushed by the immediately following freely rotatable ground roller 1 8 which also gently levels and consolidates the worked soil. Even when working with very heavy soil, a seedbed that is entirely satisfactory for agricultural purposes can usually be obtained without difficulty.

Each tine 13 is formed from a length of rod material and a circular cylindrical end thereof affords the fastening portion 12 whilst the integrally aligned soil working portion 14 also exhibits the front and rear ribs which extend from the fastening portion 1 2 to the free end of said soil working portion 14.The fact that the upper ends of the ribs abut against the lower end of the corresponding holder 10 ensures, in conjunction with the corresponding wedge 15, that the tine 13 is reliably mounted and will not move axially in the holder 1 0. The position of each wedge 1 5 is such that fouling thereof during operation of the implement is reduced to a minimum and, when required, any badly worn or damaged tine 13 can be removed and be replaced by a fresh tine, merely by using a suitable tool on the head of the corresponding wedge 1 5 to release that wedge 1 5 upwardly from the aligned recesses in which it is lodged. Despite the soil reaction forces which constantly vary in direction and magnitude as the tines 13 move through the ground, the wedges 1 5 reliably maintain the tines 1 3 in their appointed positions in a particularly simple and inexpensive manner.

Although certain features of the implement that have been described and/or that are illustrated in the accompanying 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 that has been described, and/or that is illustrated in the accompanying drawings, both individually and in various combinations.

Claims (12)

1. A soil cultivating implement of the kind set forth, wherein each soil working tool is fixed in its holder by a wedge that extends parallel or substantially parallel to the longitudinal axis or centre line of that tool.

2. An implement as claimed in claim 1, wherein each wedge is disposed in a region in which, when the implement is in operation, the soil working tool concerned exerts a minimum of pressure on the corresponding holder.

3. An implement as claimed in claim 1 or 2, wherein each wedge, the corresponding holder and a fastening portion of the corresponding tool are constructed and arranged so that, when the wedge is installed, it prevents the tool from moving turnably in the holder.

4. An implement as claimed in claim 2 or in claim 3 when read as appendant to claim 2 wherein each wedge is installed in an upper rear region of a fastening portion of the corresponding tool with respect to the intended direction of operative rotation of the soil working member concerned.

5. An implement as claimed in any preceding claim, wherein that surface of each wedge which faces a fastening portion of the corresponding tool is straight and in substantially parallel relationship with the longitudinal axis of that fastening portion whereas that surface of the wedge which cooperates with thecorresponding holder is gently inclined to said axis.

6. An implement as claimed in any preceding claim, wherein each wedge has a head that, when installed, protrudes above the top of the corresponding holder.

7. An implement as claimed in any preceding claim, wherein each wedge has an axial length whose magnitude is substantially half that of a hollow interior of the corresponding holder which receives a fastening portion of an installed soil working tool.

8. An implement as claimed in any preceding claim, wherein each soil working tool is in the form of a tine made from rod material.

9. An implement as claimed in claim 8, wherein that end of each tine which is to serve as a fastening portion thereof is of circular cylindrical configuration whereas the other end thereof has a different configuration.

10. An implement as claimed in claim 8 or 9, wherein a soil working portion of each tine exhibits ribs at both the front and rear thereof with respect to the intended direction of operative rotation of the corresponding soil working member.

11. An implement as claimed in claim 10, wherein the upper ends of said ribs abut against the lower end of the holder in which a fastening portion of the same tine is received.

12. A soil cultivating implement of the kind set forth, substantially as hereinbefore described with reference to the accompanying drawings.