GB2100561A - Rotary cultivators - Google Patents

Abstract

A rotary cultivator (10) comprises a pick tine rotor (16) which co-operates with a spring tine stator (20) positioned so as to hold the soil against the action of the rotor (16). This results in an element of shear being introduced into the soil cultivation process taking place during operation of the cultivator.

Description

SPECIFICATION Rotary cultivators The present invention relates to rotary cultivators and in particular, but not exclusively, to powerdriven rotary cultivators.

Currently available power-driven cultivators are subject to certain disadvantages, e.g. a tendency to smear the surface of the soil, to produce too fine a tilth, and to have an unnecessarily high power requirement. They are also difficult to set correctly for wet conditions in so far as too great a ground reaction from the cultivator rotor can result in wheel skid at the towing tractor.

According to the broadest aspect of the present invention there is provided a rotary cultivator comprising a set of first soil-working members which co-operate with a set of rotatable second soilworking members so as to shear soil held at least to some extent by said first members against the action of the second members. This shearing effect will take place in addition to the cultivation effects normally individually associated with the two sets of members and other cultivation mechanisms such as impact and compression may also be present.

In preferred embodiments, the second members will rotate in the same sense as any landwheels present in the cultivator. Alternatively however they could rotate in the opposite sense.

Conveniently, the cultivator will have the set of rotatable second members power-driven but it is envisaged that in some embodiments useful results may also be obtained by having these members land-driven, e.g. driven by direct contact with the soild or by a conventional or other drive from a landwheel of the cultivator.

The shear action referred to above is thought to provide a better soil breakdown that can normally be achieved with conventional designs of rotary cultivators and it also results in better trash incorporation and in a more suitable tilth, i.e. neither too fine nor too coarse, across the width of the machine.

In particular, but not exclusively, the present invention provides a rotary cultivator comprising rotatable soil-cutting "rotor" members which operate in a region of soil at least to some extent responsive to the presence of non-rotatable soilengaging "stator" members so as in operation of the cultivator to produce a shearing effect on soil in said region.

In preferred embodiments, the operative portions of the rotor members will enter the soil slightly behind the operative portions of the stator members.

Conveniently, the rotor members comprise Lblades or spikes etc., e.g. of the sort conventional to existing rotary cultivators. Alternatively the rotor members may comprise pick tines or serrated discs etc., e.g. of the sort conventional to existing disc harrows.

Conveniently, the stator members comprise tines of the sort conventional to existing rigid tine or spring tine cultivators for example. Conveniently, the operative portions of the stators are inclined at between, say, 1 and 40 to the horizontal (values of around 20 being preferred) so that they lift the soil as they pass through it.

It is also envisaged that in modifications of the above embodiments of the invention, the stator members would be removed so that the remaining rotor members become the first members and a second set of rotor members would be added to rotate in the contrary direction to the first set of rotor members so as in operation to urge soil towards said first set. Thus in these alternative embodiments of the present invention, the rotary cultivator comprises a set of rotatable first soil-working members which co-operate with a set of second soil-working members rotatable so as in operation to urge soil towards the first members. In these alternative embodiments, the members of the second set of rotor members could take any of the forms available for the members of the first set.

It has been found that in the power driven version of the cultivator of the present invention, the absorption of rotor thrust by the stationary tines has resulted in a more balanced arrangement than is available with conventional designs of rotary cultivator, i.e. the p.t.o. power of the tractor used to drive the rotor has been more suitably related to the draft power of the tractor used to pull the cultivator over the ground and this has resulted in less likelihood of wheel skid in wet conditions and smearing. Moreovear the greater efficiency of the machine allows lower rotor speeds to be used than in conventional rotary cultivators thereby reducing the power requirement and more especially the excessively high power requirement previously associated with low forward speeds.Typically, for normal forward speeds for example, the rotor speed would be reduced from the 200 r.p.m. (good soil) to 260 r.p.m. (bad soil) associated with current designs of rotary cultivator to 150 r.p.m. and 180 r.p.m. respectively, with a roughly proportionate saving in power.

These reduced rotor speeds also mean that the performance ofthe rotor will be less affected by its relationship to the forward speed of the machine making the rotor speed setting less critical than heretofore.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure l is a side view, partly broken away, of a first embodiment of the invention in which rotor members of pick-tine form co-operate with springtine stator members; Figure 2 is a plan view of the embodiment of Figure 1; Figure 3 is a side view, partly broken away, of a second embodiment of the invention in which the spring-tine stator members of the first embodiment have been replaced by rigid tines; and Figures 4a-4d show a side and perspective views of alternative designs of rotor and rotor members for use in the embodiments of Figures 1 and 2 or Figure 3.

Then referring first to Figures 1 and 2 of the drawings, a rotary cultivator 10 according to the present invention comprises a frame 12 supported by trailing landwheels 14 and carrying a rotor 16 adapted to be power driven in the same rotational sense as the landwheel 14.

The soil working members on the rotor 16 are provided by pick-tines 18 which are arranged to enter the ground slightly in front of a line of stator spring tines 20 also mounted on the frame 12. It will be observed that the operative portions of the stator tines are inclined at about 20 to the horizontal so as to provide a lifting effect on the soil as already described in general terms.

The arrangement is completed by a three point linkage (not shown) for connecting the cultivator with the tractor (not shown) which is to pull the machine over the ground and which is to provide the p.t.o. for driving the rotor 16 as above described.

The relative widths and spacings of the cooperating rotor and statortines (as viewed in Figure 2) is an important practical detail of any cultivator constructed in accordance with the present invention. With the arrangement of Figure 2, for example, there would be 15 to 20 stator tines each of some 11/2 inches to 31/2 inches width (i.e. measured in a direction across the width of the machine) with adjacent stator tines separated by 1 inch to 4 inches respectively. In this case there would be a similar number of rotor tines of 11/2 inches to 2 inches width and the same inter-tine spacing with each rotor tine positioned so as to lie in a plane mid-way between the two co-operating stator tines. The total width of such a machine might be about 10 feet, say.

As already indicated, the embodiment of Figure 3 differs from that of Figures 1 and 2 only in that rigid statortines 24 have ' een used instead of spring tines 20 and with this exception the same numerals have been used to indicate corresponding parts in the two embodiments.

Figures 4a-4d indicate some of the alternative designs of rotor element which can be used in place of pick tines 18 in the embodiments of Figures 1 and 2 and Figure 3, namely a spike tine 26 and an L-blade 28. Also illustrated is a serrated disc 30 which can be used to replace the entire rotor 16 rather than just its tines. A pick tine 18 is included for completeness. It will be appreciated of course that these various items are not to scale.

Claims (9)

1. A rotary cultivator comprising a set of first soil-working members which co-operate with a set of rotatable second soil-working members so as to shear soil held at least to some extent by said first members against the action of the second members.

2. A cultivator as claimed in Claim 1 in which the second members will rotate in the same sense as any landwheels present in the cultivator.

3. A cultivator as claimed in Claim 1 or Claim 2 in which the set of rotatable second members is power driven.

4. A rotary cultivator comprising rotatable soilcutting rotor members which operate in a region of soil at least to some extent responsive to the presence of non-rotatable soil-engaging stator members so as in operation of the cultivator to produce a shearing effect on soil in said region.

5. A cultivator as claimed in Claim 4 in which the operative portions of the rotor members will enter the soil slightly behind the operative portions of the stator members.

6. A cultivator as claimed in Claim 4 or Claim 5 in which the rotor members comprise L-blades, spikes, pick tines or a serrated disc.

7. A cultivator as claimed in any of Claims 4to 6 in which the stator members comprise rigid tines or spring tines.

8. A cultivator as claimed in Claim 7 in which the operative portions of the stators are inclined at between 15 and 40 to the horizontal (values of around 20 being preferred).

9. A cultivator substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2 of the accompanying drawings.

9. A rotary cultivator comprising a set of rotatable first soil-working members which co-operate with a set of second soil-working members rotatable so as in operation to urge soil towards the first members.

10. A cultivator substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2 of the accompanying drawings.

11. A cultivator substantially as hereinbefore described with reference to, and illustrated in Figure 3 of the accompanying drawings.

12. A cultivator as claimed in any of Claims 1 to 11 in which the first members are substantially as described with reference to, and as illustrated in, Figures4a,4b,4cor4d of the accompanying drawings.

New claims or amendments to claims filed on 5th November 1981 Superseded claims 1-10 New or amended claims: CLAIMS

1. A rotary cultivator comprising rotatable soilengaging rotor members which operate in a region of soil at least to some extent responsive to the presence of non-rotatable soil-engaging stator members so as in operation of the cultivatorto produce a shearing effect on soil in said region.

2. A cultivator as claimed in Claim 1 in which the rotor members will rotate in the same sense as any landwheels present in the cultivator.

3. A cultivator as claimed in Claim 1 or Claim 2 in which the rotor members are power driven.

4. A cultivator as claimed in any preceding claim in which the operative portions of the rotor members will enter the soil slightly behind the operative portions of the stator members.

5. A cultivator as claimed in any preceding claim in which the rotor members comprise L-blades, spikes, pick tines or a serrated disc.

6. A cultivator as claimed in any preceding claim in which the stator members comprise rigid tines or spring tines.

7. A cultivator as claimed in any preceding claim in which the operative portions of the stator members are inclined at an angle of between 15 and 40 to the horizontal.

8. A cultivator as claimed in Claim 7 in which the angle is around 20 .