GB2136261A - Soil Cultivating Implements - Google Patents

Abstract

In a soil cultivating implement of the kind in which a row of soil working members 3A extends substantially horizontally perpendicular to the intended direction of operative travel A of the implement with each soil working member 3A rotatable about the upright axis a of a corresponding shaft 2, a drive transmission from a rotary input shaft 41 to each of the soil working members 3A comprises a toothed coupling 31, 32, 33 between said input shaft 41 and all of the shafts 2. The toothed coupling 31, 32, 33 comprises a composite pinion 30A exhibiting an inner pinion 31 secured by splines and welding to the upper end of the corresponding shaft 2 and a surrounding annulus 32 having internal teeth in mesh with the external teeth of the inner pinion 31. The annulus 32 also has external teeth and is fastened directly to the bottom of an overlying bevel pinion 33 by bolts 34. An alternative construction of the toothed coupling 31, 32, 33 is described in which the bevel pinion has an integral lower collar provided with external teeth that mesh with internal teeth carried by an annular fastened to a disc secured to the upper end of the shaft 2. <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 plurality of soil working members that are rotatable by a transmission about corresponding substantially vertical, or at least upwarly extending, axes. 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 majority of implements of this kind, the transmission includes a shaft to which rotation is passed from the power take-off shaft of a tractor or other moving and operating vehicle and from which former shaft all of the soil working members are driven so that, as a consequence, very robust transmission members are necessary in association with this shaft which latter combines the resistance to rotation in the soil of all of the soil working members. An object of the present invention is to augment this strength by a construction in which the area of drivetransmitting tooth contact of pinions associated with said shaft is enlarged as compared with known arrangements.According to the inventoin, there is provided a soil cultivating implement of the kind set forth, wherein said transmission comprises a toothed coupling through which said soil working members are drivable, the toothed coupling exhibiting both internal and external teeth and the diameter of the external teeth being greater than that of a shaft to be driven by the toothed coupling.

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 constructed in accordance with the invention shown connected to the rear of an agricultural tractor, Figure 2 is a section, to an enlarged scale, taken on the line Il-Il in Figure 1, Figure 3 is a section taken on the line Ill-Ill in Figure 2, Figure 4 is an underneath plan view as seen in the direction indicated by an arrow IV in Figure 2, Figure 5 is a section to the same scale and taken on the same line as that of Figure 2 but illustrates an alternative construction in accordance with the invention, and Figure 6, is an underneath plan view as seen in the direction indicated by an arrow VI in Figure 5.

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 appropriate thinning of the seedlings, if required, can grow on to maturity. Referring now to Figures 1 to 4 of the accompanying drawings, the soil cultivating implement that is illustrated therein is in the form of a rotary harrow and comprises a hollow boxsection 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 two relatively spaced ball bearings 3 (Figure 2) that are located respectively towards the upper end, and towards the lower end, of each shaft 2. Each upper ball bearing 3 is accommodated in a corresponding bearing housing 4 that fits in an opening in the flat bottom of the hollow frame portion 1, each bearing housing 4 having a flange 4A that lies above the margin of the corresponding opening in the bottom of the frame portion 1 and to which margin it is firmly but releasably secured by a ring 5 and a plurality of small vertically disposed bolts 6.Each ring 5 surrounds the corresponding bearing housing 4 beneath the bottom of the hollow frame portion 1 and in vertical register with the flange 4A of that housing and each bolt 6 is entered through a hole in the corresponding ring 5, a hole in the margin of the corresponding opening in the flat bottom of the frame portion 1 and into a screw-threaded opening in the flange 4A of the housing 4 concerned. A spacing sleeve 7 surrounds each shaft 2 between a seal provided immediately beneath the corresponding upper ball bearing 3 and a corresponding abutment washer arranged immediately above the respective lower ball bearing 3.

Each lower ball bearing 3 is arranged in a corresponding bearing housing 9 which bearing housing 9 is secured by small vertically extending bolts 9A to the substantially horizontal limb 10 of a beam 11 that is of L-shaped cross-section, said beam 11 also having a substantially vertical limb 12 that is located at the front of the beam 11 with respect to the direction A so as to project upwardly from the substantially horizontal limb 10 of that beam 11.The beam 11 extends substantially horizontally parallel to the frame portion 1 at a level beneath that of the latter and its opposite ends are welded to corresponding side plates 13 that extend substantially vertically parallel to the direction A and to one another with each side plate 1 3 closing the corresponding end of the elongate frame portion 1 (see Figure 1). It will be apparent from Figure 2 of the drawings that each side plate 1 3 extends both forwardly beyond, and rearwardly behind, the rest of the hollow frame portion 1, considered in the direction A, as well as projecting downwardly therebelow by a considerable distance.

The side plates 13 of the hollow frame portion 1 are of substantially quadrilateral shape (see Figure 2), the leading edges thereof with respect to the direction A being straight throughout substantially the whole of their lengths and being upwardly and forwardly inclined, relative to the same direction, from bottom to top. The substantially straight rear edge of each side plate 1 3 is vertically or substantially vertically disposed and, at its lower end, is joined to the rearmost end of the corresponding horizontal or substantially horizontal lowermost edge of the same plate 13 by a short bevelled edge.

A lower end portion of each substantially vertical shaft 2 projects downwardly beneath the bottom of the corresponding lower bearing housing 9 and is axially splined. The hub-like carrier 14 of a corresponding soil working member that is generally indicated by the reference 3A is internally splined to match the external splines of the lower portion of the corresponding shaft 2 and said carrier 14 is retained on that portion of the co-operating shaft 2 by a nut 1 7 that co-operates, inside a lower recess 18 of the carrier 14, with a washer 1 5 and a short screw-threaded lowermost portion 16 of the shaft 2 concerned which portion 1 6 is of significantly smaller diameter than is the remainder of the shaft 2.The lower part of each hub-like carrier 14 in which the corresponding recess 1 8 is formed is preferably of angular shape and may conveniently, as in the example that is being described, be of square shape (see Figure 4). The upper part of each carrier 14 is, however, of circular cross-section and, as can be seen in Figure 2 of the drawings, its exterior is of very gently upwardly tapering frusto-conical configuration. Two opposite walls of the lower square cross-section portion of each carrier 14 are formed with diametrically opposed pairs of upper and lower holes that define axes which are substantially horizontally perpendicular to the longitudinal axis/axis of rotation a (Figure 2) of the shaft 2 concerned, one such axis being close to the top of the corresponding recess 1 8 whilst the other axis is close to the bottom thereof.Bolts 19 are entered through the aligned holes which define the upper and lower substantially horizontal axes that have just been mentioned and releasably secure central fastening portion 21 of two soil working tools in the form of corresponding strip shaped tines 20 to the diametrically opposed flat outer surfaces of that part of the carrier 14 through which the upper and lower bolts 1 9 are entered.

The strip-shaped material from which the tines 20 are formed is preferably, but not essentially, spring steel, the fastening portions 21 of the tines 20 of each soil working member 3A being in parallel or substantially parallel relationship with the corresponding axis a. The lower end of each fastening portion 21 is integrally connected by a I bend having a magnitude of substantially 300 to a corresponding downwardly and outwardly inclined soil working portion 22 that is straight throughout its length.The upper end of each tine fastening portion 21 is integrally joined to a straight upwardly and outwardly inclined soil working portion 24 by a bend having a magnitude of substantially 450. The end of each portion 24 which is remote from the corresponding fastening portion 21 is integrally joined by a further bend having a magnitude of substantially 900 to a downwardly and outwardly directed soil working portion 25 whose outermost free end is located at substantially the same horizontal level as is the integral junction between the upper end of the corresponding tine fastening portion 21 and the lower end of the corresponding soil working portion 24.It will be apparent from the drawings that the two tines 20 of each soil working member 3A are of symmetrycally identical construction and that, at any level, the stripshaped material of any tine 20 is in tangential relationship with an imaginary circle centered upon the corresponding axis a at the same horizontal level.The two integrally interconnected upper soil working portions 24 and 25 of each tine 20 together afford an upper operative portion that is generally indicated by the reference 23 and it will be noted from the drawings that the free end of the upper soil working portion 25 of each tine 20 is substantially in line with the free end of the corresponding lower soil working portion 22 in a direction that is parallel to the axis a concerned so that, as a consequence, the working widths of the lower parts of the tines 20 of the soil working members 3A that are afforded by their soil working portions 22 are substantially, if not exactly, equal to the working widths of the upper soil working parts of the same soil working members 3A that are afforded by the upper operative portions 23.

Each of the frame portion side plates 1 3 is provided, close to its leading edge, with an outwardly directed pivot 26, the two pivots 26 being substantially horizontally aligned in a direction that is parallel to the transverse length of the frame portion 1 itself. An arm 27 is upwardly and downwardly turnable about each pivot 26 alongside the outer surface of the corresponding side plate 1 3 and the rearmost ends of the two arms 27, which are located well behind the frame portion 1 in the direction A, carry substantially horizontally aligned bearings between which a ground roller 28 (Figure 1) is arranged in a freely rotatable manner. The construction of the ground roller is not the subject of the present invention but it preferably has an open-work, cage-like formation. Arcuately curved rows of holes 29 are formed in lower rear regions of the two frame portion side plates 13 with each hole 29 in each row at the same distance from the axis which is defined by the substantially horizontally aligned pivots 26. Each arm 27 is formed with at least one hole at the same distance from that axis and bolts 29A are provided for entry through a chosen hole 29 in each row and the hole, or one of the holes, in the corresponding arm 27. This enables the roller 28 and the arms 27 by which it is carried to be bodily displacable upwardly and downwardly about the axis defined by the aligned pivots 26, the bolts 29A being employed to maintain the roller 28 at any chosen bodily level relative to that of the frame portion 1 and soil working members 3A as long as may be required.It is this bodily level which principally determines the maximum depth of penetration of the soil working members 3A into the soil which is possible when the implement is in use.

With the exception of that one of the centre pair of shafts 2 which is shown in Figure 2 of the drawings, all of the other eleven shafts 2 are each provided, above the corresponding upper bearing housing 4, with a straight- or spurtoothed pinion 30 (Figure 1) whose hub, at its lower end, abuts against the top of the bearing housing 4 concerned, said pinion 30 being firmly and reliably secured to the corresponding shaft 2 by internal splines of its hub which co-operate with external splines at the upper end of the shaft 2 and by a circular welding seam.The provision of the co-operating splines ensures that, before the welding seam is made, each pinion 30 can be accurately positioned on the corresponding shaft 12 in a very simple manner that provides a very strong result whilst significantly accelerating the assembly procedure as compared with known assembly procedures designed to produce a similar result The pinions 30 are of such a size that each of them is in mesh with the or each immediately neighbouring pinion 30 in the single row thereof except that the single shaft 2 which is illustrated in Figure 2 of the drawings has an alternative straight-toothed or spur-toothed pinion 30A secured to its upper end by co-operating internal and external splines and a welding seam.It will be apparent that, due to the intermeshing arrangement of the pinions 30 and 30A, each shaft 2, soil working member 3A and pinion 30 or 30A revolves, during the operation of the implement, in the opposite direction to the or each immediately neighbouring similar assembly.

The pinion 30A that can be seen best in Figures 2 and 3 of the drawings drivingly links both its own corresponding soil working member 3A and all of the other eleven soil working members 3A to a rotary input shaft 41 (Figure 2) of the implement that, in the use thereof, will be driven from the rear power take-off shaft of an agricultural tractor or other propelling and operating vehicle through the intermediary of a telescopic transmission shaft 44 (Figure 1) which is of a construction that is known per se having universal joints at its opposite ends. The pinion 30A is of composite formation comprising an inner straight- or spurtoothed pinion 31 whose internally splined hub is secured to the upper end of the corresponding shaft 2 in the same manner as the pinions 30 by co-operating with splines at the upper end of that shaft and by the provision of a welding seam.The composite pinion 30A also comprises an annulus 32 that is of the same external diameter as the pinions 30 and that has matchingly shaped external teeth. However, the annulus 32 is also provided with straight- or spur-teeth around its interior and these teeth mesh with those of the inner pinion 31 (see Figure 3). The diameter of the inner pinion 31 is substantially half that of the annulus 32 and of the pinions 30.

The top of the toothed annulus 32 is formed with a shallow recess (Figure 2) whose radial extent is substantially half the radial distance between the roots of the inner and outer teeth of the annulus 32 and whose depth is substantially 1/10th of the axial thickness of that annulus. The circular recess receives the outer milled edge of a downward projection forming part of a bevel pinion 33 which lies generally above the composite pinion 30A in axial alignment therewith and with said bevel pinion 33 firmly but releasably secured to the annulus 32 of the composite pinion 30A by three bolts 34 that are spaced apart from one another at 1200 intervals round the axis a (see Figures 2 and 3).The bevel pinion 33 has an internally shouldered hub and is arranged rotatably around the lower end of a fixed shaft 35 with the aid of upper and lower ball bearings 34A whose outer races abut against the opposite sides of the shoulder in said hub. A major portion of the length of the fixed shaft 35 lies above upper ball bearing 34A and is surrounded by a closely fitting bore in a downwardly tapering support 36 forming part of a gear box 37 that is mounted on top of the hollow frame portion 1 so as to extend throughout the fore and aft width of that frame portion 1 as measured in the direction A. The bottom of the gear box registers with a large opening in flat top or cover plates of the frame portion 1.During assembly, the annulus 32 which is fastened to the bevel pinion 33 by the bolts 34 is carried by the gear box 37, the shaft 2 that is shown in Figure 2 of the drawings and the shaft 35 being moved towards one another lengthwise of the axis a until the teeth of the inner pinion 31 mesh with the internal teeth of the annulus 32 after which the bolts that secure the gear box 37 to the hollow frame portion 1 and upper and lower parts of that frame portion 1 to one another can be installed and tightened. The inner pinion 31, the annulus 32 and the bevel pinion 33 together constitute a toothed coupling exhibiting both external and internal teeth and in which the effective diameter of the external teeth is considerably larger than that of the shaft 2 that is to be driven.In addition to facilitating quick and easy assembly of the gear box 37 to the frame portion 1 in the manner that has just been described, the toothed coupling gives a uniform distribution of the forces resisting rotation over as large a tooth contact area as possible which is of considerable importance since, as mentioned above, the composite pinion 30A drives not only its own corresponding soil working member 3A but all eleven of the other soil working members 3A.

The extreme lower end of the fixed shaft 35 is integrally formed with a flat shoulder 38 against which abuts the inner race of the lower one of the two vertically spaced apart ball bearings 34A. The upper end of the fixed shaft 35 protrudes from the top of the support 36 into a recess in the top of the gear box 37, the protruding end of said shaft 35 being formed with a short length of screwthread which receives a releasable matchingiy screw-threaded fastening ring or fastening nut 39.

The teeth of the bevel pinion 33 mesh, inside the gear box 37 with those of a smaller bevel pinion 40 which is releasably secured by cooperating splines and a screw-threaded fastening ring or nut to the inner end of the previously mentioned rotary input shaft 41 which shaft extends substantially horizontally parallel to the direction A. The shaft 41, whose forwardly projection end is splined, is rotatably supported in an internally stepped portion of the gear box 37 by horizontally spaced apart larger and smaller ball bearings 42 and 43. As previously mentioned, the leading splined end of the rotary input shaft 41 is placed in driven connection with the power take-off shaft of an agricultural tractor or other propelling and operating vehicle by way of the known telescopic transmission shaft 44 which has universal joints at its opposite ends.The hollow frame portion 1 is provided, at the front thereof relative to the direction A and mid-way across the width of the implement, with a coupling member or trestle 45 (Figures 1 and 2) that is of substantially triangular configuration as seen in front or rear elevation, tie beams which can be seen in Figure 1 of the drawings being provided strengtheningly to connect the coupling member or trestle 45 to well spaced apart locations at the top and rear of the hollow frame portion 1.The coupling member or trestle 45 is intended, as illustrated somewhat diagrammatically in Figure 1 of the drawings, for connecting the free ends of the two lower lifting links of a three-point lifting device or hitch mounted at the rear of the tractor or other vehicle to horizontally spaced apart coupling points at its foot and for connecting the free end of the upper adjustable-length lifting link of the same lifting device or hitch to its apex.

In the use of the soil cultivating implement that has been described with reference to Figures 1 to 4 of the accompanying drawings, its coupling member or trestle 45 is connected to the threepoint lifting device or hitch of an agricultural tractor or other propelling and operating vehicle in the manner which has just been described and which is illustrated somewhat diagrammatically in Figure 1 of the drawings and the forwardly projecting splined end of the rotary input shaft 41 is placed in driven connection with the rear power take-off shaft of the same tractor or other operating vehicle employing the known telescopic transmission shaft 44 having universal joints at its opposite ends for that purpose.The intermeshing arrangement of the eleven pinions 30 and one composite pinion 30A ensures that, during operation of the implement, each shaft 2, soil working member 3A and pinion 30 or 30A will revolve about the corresponding axis a in the opposite direction to the or each immediately neighbouring similar assembly. Each soil working member 3A has an effective working width which is the same as, or a little greater than, the distance between immediately neighbouring axes a and, accordingly, the twelve strips of soil that are worked by the individual members 3A overlap, or at adjoin, one another to produce a single broad strip of worked soil which may advantageously have a width 3 metres when, as in the example that is being described, each soil working member 3A has an effective working width of substantially 25 cms.Other working widths are, of course, possible by employing smaller or greater numbers of the soil working members 3A in the single row thereof. Depending upon the depth setting for the soil working members 3A which is set, before work commences and if required, by bodily upward or downward adjustment of the ground roller 28 about the axis defined by the pivots 26, only the lower soil working portions 22 of the tines 20 may penetrate into the ground or both those portions 22 and the upper operative portions 23 of the same tines 20. Since the carrier 14 of each soil working member 3A is of hub-like formation, the fact that the carriers 14 also have to penetrate into the ground surface when the upper operative portions 23 of the tines are to work the soil presents no hindrance whatsoever to operation of the implement.

The particular working width of each soil working member 3A depends upon the shape and dimensions of the corresponding tines 20 and it has been found that when those tines have obliquely outwardly directed soil working portions as illustrated, by way of example, in Figure 2 of the drawings, the cyclic paths which they trace during the operation of the implement are such that the displaced soil can escape from the members 3A upwardly as well as laterally to such an extent as substantially completely to avoid the disadvantageous effect which is known as soilsmearing. It will be appreciated that the cyclic path of each soil working member 3A that has just been referred to is produced by a combination of rotation about the respective axis a together with forward progress in the direction A. An additional advantage of this construction of the soil working members 3A is that jamming of stones and other hard objects between the tines 20 of immediately neighbouring soil working members 3A very rarely, if ever, happens whilst the rate of wear of the soil working member carries 1 4 is very low.

The construction of the carriers 14 which has been described enables one of the shafts 2, the corresponding ball bearings 3, their housings 4 and 9 and the respective pinion 30 or inner portion 31 to be assembled from the top of the hollow frame portion when the or each flat top of cover plate of the latter is missing, some of said parts being entered downwardly through the corresponding opening which is formed in the flat bottom of the hollow frame portion 1. The bearings 3 and their housings 4 and 9 form a support for each shaft 2 and, when the parts just discussed have been installed, the lower bearing housings 9 will be entered in openings formed in the substantially horizontal limb 10 of the beam 11 and the flanges 4A of the upper bearing housings 4 will rest on top of the margins of the openings in the flat bottom of the hollow frame portion 1.The next assembly step is to install the flat top or cover plates of the frame portion 1 which lie at either side of the gear box 37 and finally to install that gear box 37 itself in the manner discussed above which engages the external teeth of the inner pinion 31 with the internal teeth of the surrounding annulus 32 to complete the composite pinion 30A. It is only then necessary to secure the gear box 37 in its installed position by means of the bolts whose positions can be seen in Figures 1,2 and 3 of the drawings. The tines 20 are secured to the carriers 14, after the installation procedure which has just been described, by using the bolts 1 9 to clamp their fastening portions 21 against the flat opposite surfaces of the lower part of each carrier 14 that defines the internal recess 1 8 thereof.The recess 1 8 facilitate ready installation and removal of the tines 20. The provision of the L-shaped cross-section beam 11 at a level well below that of the hollow frame portion 1 ensures a very effective rotary support of the shafts 2 in a simple manner and avoids any need for rotary support of the shaft 2 at the top of the hollow frame portion 1 and also any need to strengthen that top. Both assembly and disassembly of the implement are facilitated by the construction and procedure that has been described.

Figures 5 and 6 of the drawings illustrates an alternative embodiment in which, however, many of the parts are very similar, or identical, to parts that have already been described with reference to Figures 1 to 4 of the drawings. Accordingly, such parts are indicated in Figures 5 and 6 by the same references as are used in Figures 1 to 4 and will not be described again in detail. In this embodiment, the lower axially splined end of each shaft 2 that projects from beneath the bottom of the corresponding bearing housing 9 is surrounded by an upwardly tapering upper portion of a corresponding carrier 46, each such carrier 46 having an internally splined upper recess which receives the lower end of the corresponding shaft 2 and a plain axially extending lower recess 48 which is smaller in diameter than is one of the previously described recesses 1 8 in the first embodiment.The upper and lower recesses are of substantially the same diameter and the longitudinal axis of each of them coincides with the corresponding axis a, said recesses being separated from one another by a centrally apertured wall 47 that extends substantially horizontally perpendicular to the axis a concerned. A screw-threaded stub at the extreme lowermost end of each shaft 2, which stub is of considerably reduced diameter as compared with the remainder of that shaft 2, is entered downwardly through the aperture in the corresponding wall 47 and receives the previously mentioned fastening nut 1 7 below that wall, said nut 1 7 preferably, but not essentially, being of a known kind which incorporates means tending to prevent it from being worked loose by vibration.

Substantially the lower half of each carrier 46, beneath the level of its internal wall 47, is of increased diameter and is of circular cross-section (see Figure 6). This lower half is formed with the corresponding lower recess 48 whose diameter is substantially the same as that of one of the shafts 2. Obliquely aligned bores are formed in upper and lower regions of the lower enlarged half of each carrier 46 at relatively oppositely sides of the corresponding axis a, each pair of bores defining an axia which is inclined at substantially 450 to the corresponding axis a and, consequently, said axes intersecting each other (as seen in Figure 5), at an angle of 900 at a point which also, as seen in Figure 5, intersects the corresponding axis a).The lower bores open from obliquely inclined mouths located at opposite sides of the corresponding axis a and at opposite sides of the downwardly directed mouth of the lower recess 48. Each pair of bores receives a corresponding soil working tool in the form of a tine 49 produces from a straight length of metallic rod. Each tine 49 projects both obliquely upwardly and obliquely downwardly from the bores in the lower half of each carrier 46, each tine 49 defining an upwardly projecting upper operative portion 50 and a downwardly projecting lower operative portion 51 with each projecting portion 51 being substantially, if not exactly, twice the length of each projecting portion 50.

The upper end of each upper operative portion 50 is bevelled at 450 so as to extend substantially horizontally perpendicular to the corresponding axis a whereas the lowermost end of each lower operative portion 51 is bevelled at 450 so as to extend substantially, if not exactly, vertically parallel to that axis a.

The tines 49 are prevented from moving either axially or rotationally in the bores of the lower halves of the carriers 46 through which they are entered by forming substantially horizontal openings in the walls of the carriers 46 so as perpendicularly to intersect the corresponding upper bores in those carriers, pins 52 being entered retainingly through said openings and through registering openings, of matching size, that are formed in the tines 49 themselves. It will be obvious from Figure 5 of the drawings that the diameters of the pins 52 and the openings which receive them are much smaller than those of the tines 49. The pins 52 may be prevented from working loose in any convenient known manner, the longitudinal axes of the openings which receive them being substantially horizontally perpendicular to the corresponding axis a.

In this embodiment, the toothed coupling which interconnects the rotary input shaft 41 and the shafts 2 that correspond to the respective soil working members 3A is again arranged principally inside the gear box 37 and comprises a circular disc 53 having a central hub which is mounted at the uppermost splined end of the corresponding shaft 2 by way of co-operating internal splines of the hub and a circular welding seam at the uppermost end of that hub. The disc 53 extends perpendicular to the longitudinal axis a of the shaft 2 concerned. The outer periphery of the disc 53 is secured by a plurality of regularly spaced apart bolts 54 to an annulus 55 whose base is formed with a recess shaped to match the periphery of the disc 53.The annulus 55 has external straight- or spur-teeth and is of the same diameter as one of the previously described pinions 30, said annulus 35 also comprising, however, radially inner straight- or spur-teeth which mesh with those of a circular collar 56 integrally forming a downward projection of a bevel pinion 57 whose upper bevel teeth are in driven mesh with those of the previously described smaller bevel pinion 40 carried by the rotary input shaft 41. It will be seen from Figure 5 of the drawings that the hub of the bevel pinion 57 is rotatably connected to a lower end region of the fixed shaft 35 in substantially exactly the same way as has already been described above with reference to the first embodiment, said shaft 35 being firmly but releasably mounted in the gear box 37 in axial alignment with the shaft 2 associated with the toothed coupling.The external teeth of the annulus 55 are, of course, in driving mesh with those of neighbouring pinions 30 corresponding to further soil working members 3A of the same implement.

The toothed coupling which comprises the parts 53, 55 and 57 provides the same advantages as have been mentioned in connection with the first embodiment and particularly ensures that the tooth contact area through which driving forces are transmitted, and forces opposing drive, which are sometimes very high, is as large as possible. All four of the three external and one internal sets of teeth that are exhibited by the toothed coupling have diameters which are considerably greater than the diameter of each shaft 2 which is to be driven.

The operation of the implement of Figures 5 and 6 of the drawings is similar to that which has already been described with reference to Figures 1 to 4 thereof. Its tines 49 can be made in a very simple manner from straight rod material which preferably, but not essentially, is of circular cross section. Once again, the fact that the tine carriers 46 themselves will have to penetrate beneath the surface of the soil if the upper operative portions 50 of the tines are to work that soil as well as the lower operative portions 51 thereof in no way hinders the performance of the implement due to the particular construction of the carriers 46.

Also, as in the case of the first embodiment, the assembly and disassembly of the implement can be effected both quickly and easily since the shafts 2, the tine carriers 46, the upper and lower bearing housings 4 and 9, the pinions 30 and the disc 53 can be installed downardly in a unitary manner followed by installation of the tines 49 and their retaining pins 52. The gear box 37 carrying the bevel pinion 57 is installed lengthwise of the corresponding axis a until the external teeth exhibited by the circular collar 56 of the pinion 57 mesh with the internal teeth of the annulus 55 after which a simple bolting operation is all that is required to complete the assembly.

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

Claims (26)

1. A soil cultivating implement of the kind set forth, wherein said transmission comprises a toothed coupling through which said soil working members are drivable, the toothed coupling exhibiting both internal and external teeth and the diameter of the external teeth being greater than that of a shaft to be driven by the toothed coupling.

2. An implement as claimed in claim 1, wherein said toothed coupling lies between a rotary input shaft and the remainder of the transmission to said soil working members.

3. An implement as claimed in claim 1 or 2, wherein the toothed coupling comprises a straight- or spur-toothed pinion arranged immediately beneath a bevel pinion, and wherein said straight- or spur-toothed pinion has its teeth in mesh with other straight- or spur-toothed pinions mounted on driving shafts of corresponding soil working members.

4. An implement as claimed in any preceding claim, wherein said toothed coupling is constructed and arranged to transmit drive to a shaft disposed substantially centrally of a row of shafts from which corresponding soil working members are drivable, and wherein the toothed coupling comprises teeth at substantially the level of the upper end of this substantially central drive shaft, those teeth being in driven mesh with teeth connected to a lower portion of a bevel pinion or of said bevel pinion.

5. An implement as claimed in claim 4, wherein the teeth located at substantially the level of the upper end of said substantially central drive shaft are the external teeth of an inner pinion of a composite pinion which also comprises a surrounding annulus having internal teeth in driving mesh with those external teeth, said annulus being secured to a lower portion of said bevel pinion and also exhibiting external straight- or spur-teeth that are arranged in driving mesh with those of pinions carried by drive shafts to other soil working members of the implement.

6. An implement as claimed in claim 4, wherein the teeth at substantially the level of the upper end of said substantially central drive shaft are in the internal teeth of an annulus carried by a disc that is secured to the upper end of said substantially central drive shaft, and wherein said internal teeth are in driven mesh with external teeth of a lower portion of said bevel pinion which they surround, said annulus also having external teeth in driving mesh with those of neighbouring pinions carried by drive shafts to other soil working members of the implement.

7. An implement as claimed in any one of claims 4, 5 or 6, wherein said bevel pinion is rotatable about the axis of a shaft fixed in a gear box carried on top of a hollow frame portion of the implement in which frame portion the drive shafts corresponding to the several soil working members of the implement are rotatably supported.

8. An implement as claimed in any one of claims 4 to 7, wherein said pinion, or said disc, that is carried at the upper end of said substantially central drive shaft is secured to that upper end by welding.

9. An implement as claimed in claim 8, wherein the upper end of said substantially central shaft is splined, and wherein a hub of said pinion or of said disc is matchingly internally splined, the splines being interengaged prior to welding said hub to said shaft.

10. An implement as claimed in any preceding claim, wherein the construction of the drive transmission and of a frame portion, or said frame portion, which partially accommodates that drive transmission is such that a shaft or said substantially central drive shaft, together wtih two relatively spaced bearings for the rotation of that shaft, a toothed pinion or annulus or said toothed pinion or annulus secured to the upper end of the shaft and a carrier of a corresponding soil working member can be unitarily installed into the implement from above by entering it through an opening formed ins aid frame portion.

11. An implement as claimed in any preceding claim, wherein each soil working member comprises a carrier, or said carrier, which is arranged at the lower end of the corresponding shaft, the carrier being constructed and arranged to support at least one soil working tool of the corresponding soil working member and being of a hub-like construction provided with a part to which the or each soil working tool is securable which part is of hollow formation.

12. An implement as claimed in claim 11, wherein the hollow part of each carrier is in coaxial relationship with the longitudinal axis of the corresponding drive shaft to the soil working member concerned, said carrier being secured to that drive shaft by fastening means located internally of the hollow part of the carrier.

13. An implement as claimed in any preceding claim, wherein each soil working member comprises a carrier provided with two soil working tools arranged in relatively crossing relationship.

14. An implement as claimed in any preceding claim, wherein each soil working member comprises an upper operative portion, a lower operative portion and a fastening portion, the or each lower operative portion being in outwardly inclined relationship with the corresponding fastening portion.

1 5. An implement as claimed in claim 14, wherein the fastening portions of the soil working tools lie between respective upper and lower operative portions thereof, said fastening portions being in parallel or substantially parallel relationship with the longitudinal axis of the corresponding soil working member.

1 6. An implement as claimed in claim 15, wherein the fastening portions of the soil working tools are secured to outer surfaces of the corresponding soil working member carriers, said outer surfaces being those of hollow hub-like parts of the corresponding carriers.

1 7. An implement as claimed in any one of claims 14 to 1 6 when read as appendant to claim 11, wherein said two soil working tools of each soil working member are disposed diametrically opposite to one another with respect to the intended axis of rotation of that soil working member, and wherein the fastening portions of each pair of tools are secured to the corresponding carrier by two bolts or like elongate fastening elements arranged one above the other and entered transversely through the hollow part of that carrier.

18. An implement as claimed in any one of claims 14 to 17, wherein each soil working tool is of strip-shaped formation and is so arranged with respect to the corresponding carrier that the flat side thereof is in tangential or substantially tangential relationship with an imaginary circle centred upon the intended axis of rotation of the corresponding soil working member.

19. An implement as claimed in claim 13 or 14, wherein each soil working tool comprises upper and lower operative portions which are located at relatively opposite sides of the intended axis of rotation of the corresponding soil working member.

20. An implement as claimed in claim 19, wherein each upper operative portion has a length which is substantially half that of the corresponding lower operative portion.

21. An implement as claimed in any one of claims 13, 14, 19 or 20, wherein when seen in a direction that is perpendicular to the intended axis of rotation of one of the soil working members, the fastening portions of the corresponding two soil working tools are in crossed relationship with one another.

22. An implement as claimed in claim 21, wherein the crossing fastening portions of said soil working tools are so positioned relative to the intended axis of rotation of the corresponding soil working member that an imaginary straight line will intersect that axis and the longitudinal axes of both fastening portions.

23. An implement as claimed in any one of claims 19 to 22, wherein each soil working tool is secured in a bore in the wall of the corresponding hub-shaped soil working member carrier by a transverse retaining pin.

24. An implement as claimed in any one of claims 19 to 23, wherein each soil working tool is in the form of a tine made from a length of rod.

25. An implement as claimed in claim 24, wherein the opposite ends of said rod are so bevelled that the upper end of the upper operative portion thereof is perpendicular or substantially perpendicular to the intended axis of rotation of the corresponding soil working member whereas the end of the lower operative portion thereof is so bevelled as to be in parallel or substantially parallel relationship with that axis.

26. A soil cultivating implement of the kind set forth substantially as hereinbefore described with reference to Figures 1 to 4 or to Figures 1, 5 and 6 of the accompanying drawings.