IMPROVEMENTS TO PLOUGHS, ARRANGEMENTS AND IMPLEMENTS THEREFOR AND METHODS OF CULTIVATION USING SAME

Abstract: A tool arrangement for use in an agricultural plough employs a rotatable share (2) with a cutting rim (43) designed to penetrate soil to a shallow depth in order to skim trash as the arrangement is moved over the soil surface (S). A soil share (4) is positioned behind the skimming share (2) and is set at different angle to penetrate the soil at one side of the path of the skimming share (2) and to displace soil to bury the trash.

Description: IMPROVEMENTS TO PLOUGHS, ARRANGEMENTS AND IMPLEMENTS THEREFOR AND METHODS OF CULTIVATION USING SAME TECHNICAL FIELD This invention relates in general to ploughs as used in agriculture ; in particular the invention is concerned with post-harvest straw incorporation ploughs and to various too l arrangements f rames and sub- assemblies for use with ploughs . BACKGROUND TO THE INVENTION Following the harvest of a crop it is necessary to cultivate the soil prior to planting the next crop. Typical cultivation operations are ploughing, harrowing and sub-soiling. Many crops during their growth-cycle produce not only that part of the crop which the farmer wishes to harvest and to use as feed stock, sell or otherwise, but also other parts which are considered by the farmer as waste product in so much as that they will not be of immediate benefit to him or be of no benefit at all. For example, in the case of potatoes only the tuber itself is of any use. The leaves, stem and roots are waste. Unwanted plant matter or waste product is often referred to as "straw" or "trash". The method traditionally favoured for dealing with waste product has been by burning the unwanted parts of the crop after harvesting the wanted produce. This is usually carried out in situ on the field at or near the place where this crop grew. The burning method has been favoured for a number of reasons, primarily because the job can be completed at very little expense. After burning, the ground is left in a suitable condition for planting the next crop. This particularly applies to subsequent cultivation operations which can be adversely affected by an excess of plant matter remaining on or near the ground surface. Recent and further proposed changes in legislation, however, require the burning method to be discontinued. Although several alternative methods for dealing with the unwanted plant material exist, there are two main methods in common use. One method comprises the removal of the majority of unwanted plant matter from the field (straw removal). The other method involves destruction of the majority of unwanted plant matter in situ (straw destruction). Straw removal is labour intensive, costly, and not altogether effective. Straw destruction, on the other hand, may be accomplished in a variety of ways, ranging from chemical and bacterial methods to mechanical methods and is implemented for a variety of reasons. Chemical and bacteriological methods change the chemical composition and structure of the material whilst mechanical methods reduce the physical size or bulk of material. In general these straw destruction methods may be used in combination with each other, and as such may be referred to as straw incorporation. The main purpose of straw incorporation is to remove most or all of the unwanted plant material from the ground and attempt to bury or partly bury most of this matter in the soil. Another purpose is to stop this unwanted material becoming entangled in equipment used during cultivation or other operations carried out by the farmer in preparation for the next crop. It can be advantageous to bury or partly bury unwanted plant matter since the material tends to be reduced in quantity by the natural processes occurring in the soil. This can also provide nutrients for the following crops. This also effects the immediate micro¬ climate of these future crops. Such an excess of' material in a ground surface can also cause adverse conditions for the following crops, for instance, by means of bacteriological and/or chemical reactions or by restricting the growth of new shoots. Straw incorporation is often carried out using an agricultural instrument known as a mould-board plough which inverts this top layer and thus buries the surface matter. In this arrangement, the plough share, that is, the part of the device which turns over the soil, is fixed relatively to a frame and during use large forces act upon the share and the frame. This combined with the very nature of ploughing requires a relatively large input of energy in order to achieve straw incorporation. This results in the need for high powered agricultural machinery. An alternative method to the mould-board plough is the disc plough. The disc plough has rotating shares which turn over the soil and are more energy efficient than the fixed share mould-board plough. Unfortunately the problem with the rotating share plough is that it tends to be less accurate in the manner in which the soil is turned over. This results in incomplete straw incorporation. Both types of prior art ploughs tend to invert a sod of soil with the plant matter almost intact, which is not desirable. Ideally trash should be mixed with a small amount of soil which is subsequently buried beneath a shallow layer of soil containing substantially little trash. A further characteristic of prior types of plough is that since material is moved to one side there is a resultant force which moves the implement and thus the direction. As a result it is quite difficult to maintain a straight path along a field. This unwanted effect has been countered by various methods and devices such as fixed plates of metal known as landsides or rotating discs or wheels which engage the soil and prevent movement away from the side to which the soil was moved. Unfortunately the problem with these side force counteracting devices is that a substantial amount of extra drag is caused. The total amount of energy required to move the implement forwards is therefore increased drastically. Due to this need for counter balancing, not only is the ploughing operation energy inefficient but in some cases, due to the nature of the soil, only high powered tractors can cultivate particular fields. The present invention seeks inter alia, to provide improved means for straw incorporation. DISCLOSURE Of THE INVENTION In one aspect the present invention provides an agricultural implement or tool arrangement having a number of rotatable tools for skimming soil or trash which are used in conjunction with other conventional fixed or rotating shares for soil displacement. According to the invention a tool arrangement According to the invention a tool arrangement comprises a rotatably mounted first or trash share with a cutting rim set at an angle partly to penetrate soil to a pre-determined first depth and to impart rotation of the first share as the arrangement is progressively moved along a soil surface in a towing direction and a soil share disposed behind and to one side of the first share relative to the towing direction, the soil share being set at a different angle to the cutting rim of the first share to penetrate the soil to a pre-determined second depth. The rotating share can predominantly displace trash and some soil to said one side and the soil share displaces further soil to cover the trash and create a furrow. One way of setting the cutting rim of the first share at an angle is to arrange the rotational axis of the first share at an angle to the vertical. A plough frame sub-assembly for towing behind a tractor can be used to mount the tool arrangement and a plough frame may include a number of such sub-assemblies with tool arrangements with several trash shares and several soil shares. Such further sub-assemblies may be positioned to the side or to the rear and the side of the first or leading plough sub-assembly. A plough frame in accordance with the invention may then comprise one or more rotatable trash skimming soil shares are set at different working angles relative to the direction of movement of the plough. The skimming tool or tools operate in one or more orientations to skim trash from the soil surface whilst advantageously mixing the trash with a small amount of soil and spreading the mixture into a furrow while the soil displacement tool or tools then cover the trash/soil mixture with a layer of soil. According to another aspect of the invention there is provided in or for a plough, a frame arrangement connectable to a piece of frame machinery, such as a tractor, for towing; said frame arrangement carrying as a sub-assembly at least one first or trash share and at least one soil share, wherein the first share is a rotatable member having a rim acting as a skimming edge and with an axis of rotation offset from a perpendicular to the direction of towing and said soil share cooperates with the trash share to cover the soil or straw/soil mixture previously positioned by the trash share. The first or trash share may be configured as a concave or cupped-disc or a top hat with a cupped edge. It is preferable that the trash share rotates about an axis which is inclined forwardly and τ,o one side. This sets the skimming edge at an angle to the towing direction and has been found to be particularly direction and has been found to be particularly effective. Another form of trash skimming device in accordance with the invention, is a planar disc with a frusto-conical cupped edge or a concave disc again set with its axis of rotation to the front and to the side of the vertical. A still further form of trash cutting device may comprise a concave disc and a blade or wall fixed above the rotating disc to scrape, remove, guide and deflect the loosened material to the rear and to one side. In accordance with another aspect of the invention, there is provided a trash skimming device in the form of a tool of general top-hat shape or a concave disc with a cupped cutting edge, the edge or rim being either wide or narrow in relation to the diameter of the crown. The tool can be positioned so that it has an axis of rotation which is canted to the front and to the side of the vertical with respect to a forward direction along which the device is moved. In operation this device skims the ground surface at a shallow working depth moving as much trash as possible with which a small amount of soil is incorporated therein. By reason of the axis of rotation being angled slightly forward, the material is collected at the leading edge, and since the axis is also angled to one side, the share is rotated by its engagement with the ground surface. The trash residue is then collected around the periphery of the cutting edge and deposited to one side. The rotatable shaped tool assists in achieving the desired high forward velocity as it tends not to displace the trash/soil to such an extent as prior art implements. It is also preferable that at least some or all of the shares following the trash shares or the primary trash shares may pivot in order to enable furrows to be directed to either side of a frame or plough sub- assembly mounting the arrangement. It is possible to have the trash shares set with their rotational axes parallel to one another but it is possible to provide groups of trash share each with parallel rotational axes and the axes of the groups of shares are inclined in different direction but preferably symmetrically. According to a further aspect of the invention there is provided a method of cultivation or ploughing using a plough tool arrangement composed of at least one rotatable trash share and at least one soil share set at different working angles and comprising the steps of disposing a forward-most cutting rim of the primary trash share angled towards one side and slightly into the soil and disposing the soil share rearwardly of the trash share and moving the arrangement progressively over the area to be ploughed at sufficient speed whereby the trash share is rotated by contact with the soil to remove and displace trash in an upper soil layer to one side and the soil share follows in the path cleared by the trash share and displaces further soil in order to cultivate said soil with a reduced amount of trash therein. The displaced soil can be repositioned to one side and on top of the previously displaced trash. It is preferable that the trash share is positioned to penetrate into the soil to a depth of approximately 15 cm and the soil share is positioned to penetrate into the soil to a depth of approximately 20 cm. The forward speed of the plough frame arrangement relative to the ground can be relatively high e.g. 8 km/h, but the actual speed is not important. In one embodiment, a secondary trash share follows the soil share and subsequently repositions the trash towards the ploughed side of the frame arrangement and into the path behind the soil share. It is possible for the soil shares and secondary trash shares to be angled backwards. This causes them to displace less material forwardly and more material rearwardly. This also tends to reduce the extent of soil being turned over intact and fashion across the path whilst reducing the draught. In operation the soil shares and the secondary trash shares displace material sideways and in so doing cover a previous path of trash and spread trash across a previously cleared furrow. BRIEF DESCRIPTION OF DRAWINGS The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description and the accompanying drawings, wherein: Figure 1 is a schematic plan view representation of a plough arrangement constructed in accordance with the invention; Figure 2 is a schematic front view perspective of the arrangement shown in Figure 1; Figure 3 is another schematic front view representation of the arrangement shown in Figure 1; Figure 4 is a schematic side view representation of part of the arrangement shown in Figure 1; Figures 5 to 8 are schematic plan view representations of further arrangements constructed in accordance with the invention; Figure 9 is a schematic plan view of a plough frame sub-assembly incorporating a tool arrangement in accordance with the invention; Figure 10 is a schematic side view of the sub- assembly depicted in Figure 9; Figure 11 is a schematic plan view of another plough frame sub-assembly incorporating a tool arrangement in accordance with the invention; Figure 12 is a schematic side view of the sub- assembly depicted in Figure 11; Figure 13 is a schematic plan view of a further plough frame sub-assembly incorporating a tool arrangement in accordance with the invention; Figure 14 is a schematic side view of the sub- assembly depicted in Figure 13; Figure 15 is a schematic front view of sub- assembly shown in Figures 13 and 14; Figure 16 is a schematic plan view of another tool arrangement constructed in accordance with the invention; Figure 17 is a schematic plan view of further plough frame sub-assembly incorporating a tool arrangement in accordance with the invention; Figure 18 is a schematic side view of the sub- assembly depicted in Figure 16; Figure 19 is a schematic plan view of a further tool arrangement constructed in accordance with the invention; and Figures 20, 21 and 22 are diagrammatic views serving to compare a prior art plough share with an equivalent tool of an arrangement in accordance with the invention. BEST MODES FOR CARRYING OUT THE INVENTION As shown in Figures 1 to 4, a tool arrangement for use with a plough has two trash shares 2 and two soil shares 4. The shares 2, 4 are each in the form of a concave disc with a central crown 41 and a rim 43. The diameter of the rim 43 of each disc 2 is typically 66 cms and the diameter of the rim 43 of each disc 4 is typically 81 cm. The rim 43 is offset from the crown 41 by a distance of 90 mm for each disc 2 and 115 mm for each disc 4. The discs 2 have spigots 20 projecting axially of the crown 41 which are rotatably supported on spindles 21. The axes of rotation P of the discs 2 are inclined to both a soil surface S to be treated and to the intended direction of motion of the plough and the tool arrangement which is indicated by arrow 8. The angle of inclination of each axis P in relation to a vertical plane normal to the direction of motion 8 is in the range 37£ ± 20 degrees and more preferably 37| ± 10 degrees, as viewed from the front (left-hand side of Figure 1) and 22 ± 10 degrees degrees as viewed from the side (bottom of Figure 1). The soil shares or discs 4 can be fixed in or adjustable about a position rearwardly and to one side of the trash shares or discs 2 with their crowns 41 facing away from the discs 2. In this embodiment each trash share 2 is followed by one of the soil shares 4. The discs 2, 4 may each have an uninterrupted rim 43 as shown but it is possible to provide cut-outs in the rims 43 of the discs 4. During use of a plough or a plough sub-frame mounting the tool arrangement shown in Figures 1 to 4 the arrangement travels behind a tractor or towing vehicle in the direction of arrow 8 and contact between the soil and the trash shares 2 causes these to rotate in the direction of arrow 10 about the inclined axes P. The rotating trash shares 2 generally penetrate the soil with part of the leading portions of their rims 43 to a depth of about 15-20 cm and cause just the top layer of soil to be removed together with a substantial amount of unwanted plant matter or trash from the surface. The trash shares 2 are designed to reposition material towards the unploughed side of the arrangement in a place advantageous to the following soil shares 4. The soil shares 4 generally invert the soil and trash positioned by the trash shares 2 and also penetrate the soil to a depth of approximately 15-20 cm. Each soil share 4 can be positioned to travel along a path onto which some of the trash has been previously positioned by the associated leading trash share 2. The soil shares 4 create furrows and in doing this the soil is displaced and broken up. This broken up soil is also moved to one side where it is positioned on top of the trash positioned by the trash shares 2. In multiple passes trash can be generally positioned in the furrows created by a previous soil share path. In the embodiment as described and illustrated the diameter of the spigot 20 of each disc 2, 4 can be 10 to 30% of the diameter of the rim 43. In a modified form suitable for the trash shares 2, the spigot 20 is enlarged or the crown 41 and the spigot 20 are enlarged to provided a tool with the shape of a top hat as depicted in the other Figures of the drawings. Throughout the following description and drawings like reference numerals are used to designate similar parts and functions and the various illustrations of shares of top hat shape are not intended to be limited to this design and the concave disc, for example, can be adopted instead. Figures 20, 21 and 22 compare a typical prior art disc 2a with a trash share 2 of the present invention. Figure 20 is a schematic view from above whilst Figures 21 and 22 are schematic views from the front showing in detail the cutting depth and width of the prior art disc compared with the trash share of the present invention. For the purpose of this comparison it has been assumed that the prior art disc 2c is angled at approximately 45° to the direction of travel and the trash share 2 is angled at around 10-15° that is leaning forward and to one side of the direction of travel. It can be clearly seen that a trash share according to the present invention will cover a wider width of the surface for a given depth and a given diameter than with a prior art disc 2c. Figure 5 depicts an arrangement with a primary trash share 2, a soil share 4 and a secondary trash share 6. The shares 4, 6 are concave discs whilst the share 2 is of top hat shape. The shares 4, 2 co-operate as described and the soil tends to move in the direction of arrow 12. The secondary share 6 follows in part of the path of the soil share 4 and repositions any remaining trash in the direction of the arrow 14 and into the furrow left by the operation of the soil share 4. Figure 6 shows an implementation of the invention wherein there are two trash shares 2 which are designed to rotate in a direction opposite to that of the trash shares 2 shown in the embodiments in Figures 1 to 5. The primary trash shares 2 clear the unwanted matter from in front of the single following soil share 4 by moving this matter towards the ploughed side of the implement and into a vacant furrow allowing the following soil share 4 to cover the trash with soil. In the arrangement according to Figure 5, the primary trash share 2 contra-rotates relative to action of the soil share 4 and the secondary trash share 6 due to their being angled towards different sides of the plough sub-assembly. The side forces due to the shares 2, 4 and 6 are therefore effectively cancelled out. In the arrangement of Figure 6 however, since the primary trash shares 2 and the soil shares 4 act in the same direction, the design is not so inherently counter¬ balanced. It is preferable that there is a second plough sub-assembly with further arrangements angled behind and to the unploughed side of the leading or first plough sub-assembly. Thus, by way of example. Figures 7 and 8 respectively show embodiments of the invention having two sub-assemblies according to Figures 5 and 6. Figure 9 depicts a sub-assembly with a frame 22 with supports 23 mounting two primary trash shares 2, two soil shares 4 and a secondary trash share 6. Since the primary trash shares 2 are angled to throw trash in a direction opposite to that of the soil shares 4 and the secondary trash shares 6, a side-force counter balancing effect is induced. Figure 10 is a side view of the embodiment as depicted in Figure 9 which shows the depths of penetration. Thus, the soil or ground level is designated S; the depth to which the primary trash shares 2 and the secondary trash share 6 operate is designated 18; and the depth to which the soil shares 4 operates is designated 30. Figures 11 and 12 show respectively the overhead view and the view from the front of an embodiment of the invention comprising three units based on the design shown in Figures 9 and 10. Figure 13, 14 and 15 show, respectively an overhead view, a side view and a view from the front of a further embodiment of the present invention. The primary trash shares 2 each comprise a rotatable concave disc 2 similar to Figures 1 to 4 with a deflector plate 2b shaped to fit just above the disc 2 to one side of its axis of rotation P. There is sufficient gap to allow rotation yet ensure that, in operation, most of the trash/soil mixture is displaced to the rear and to the side of the arrangement. In Figures 14 and 15 the references S, 18 and 30 correspond with those in Figure 10. Figure 16 shows a further embodiment of the invention wherein the primary trash shares 2 are concave discs and precede the secondary trash shares 6. These secondary trash shares 6 precede, in turn, the soil shares 4. The dashed lines depict an alternative configuration for a second ploughing pass in the opposite direction to a first or previous ploughing pass. The shares 2, 6, 4 are mounted for pivoting between the alternative operating positions. Reference numbers 28 denotes the pivot joints for the various plough shares. The pivotal paths of the secondary trash shares 6 and the soil shares 4 overlap and for the pivoting operation is best carried out sequentially upon reversal of the ploughing direction. In this arrangement, the two concave primary trash shares 2 throw material in an opposite direction to the secondary trash shares 6. The furrow set sub-assemblies are positioned side-by-side. Figure 19 shows an overhead view of an embodiment similar to that depicted in Figure 16 except that primary trash shares 2 are of top hat shape. In the various embodiments described and illustrated in Figures 1 to 16 and 19, where there are multiple trash shares 2, the inclined axes of rotation P are all parallel. This is not essential and indeed there can be advantage in arranging the shares 2 in co¬ operating groups with the axis of rotation P^ of one group being parallel to one another and the axes of rotation P2 of the other group also being parallel to one another but inclined in a different direction to the axes P^ of the first group. During use the groups of shares 2 then rotate in opposite directions. The inclination of the respective axes of rotation P^, P2 of co-operating pairs of shares 2 of the groups are preferably symmetrical to one another relative to a vertical plane A-A therebetween, as 'shown in Figures 17 and 18 which are based on a variation of the sub-assembly shown in Figure 9. The arrangement shown depicts only one variation in which the contrary inclination of two primary trash shares 2 as illustrated is merely exemplary and such a principle can be adopted in a variety of other practical arrangements. The sequence of operations of the arrangements and assemblies will now be described in more detail. The passing over of a primary trash share 2 followed by a soil share 4 and optionally a secondary trash share 6 completes an operation which will be referred to as a furrow pass. Each furrow pass has the effect of creating three paths in the field: 1. A path of displaced soil; 2. A furrow path with unwanted plant matter within it; and 3. A path of ground surface with a substantially reduced amount of unwanted plant matter on it. If the ploughing arrangement has two or more plough sub-assemblies then further furrow passes would be created, each making a furrow pass approximately one furrow pass width to the side of an adjacent furrow pass. The soil turned by the soil share 4 during the subsequent pass should be positioned substantially on top of the unwanted plant matter positioned by the previous pass, this sequence is then repeated across the field. If the ploughing direction is reversed at the end of each furrow pass or set of furrow passes then the shares 2, 4, 6 will have to be pivoted about their pivot axis 28 in order that the unwanted plant matter is positioned to the opposite side of the arrangement and thus towards the same side of the field as the previous pass. Conventional multiple ploughing implements are designed with the soil engaging devices diagonally arranged on the carrying frame. This enables a following device to reposition soil that it moves into the furrow behind the preceding device. Since certain multiple ploughing arrangements according to the present invention may be mounted side-by-side on the carrying frame, the overall length of the implement is much reduced compared to the conventional arrangement. The frame may accordingly be much lighter and has a centre of gravity more proximate the tractor. This reduces the loading on the tractor, both in.use and when non-working in a raised position for manoeuvring or transportation. The arrangements according to the present invention are also advantageous for a number of other reasons. The plough can be mechanically simple and hence relatively cheap. The simple implements and also devices are less prone to blockage than more complex devices may be. Secondly the plough is easily reversible and short in length. Thirdly the frame and sub-assembly arrangements can be made to produce counteracting forces resulting in little tendency to pull to one side in use. In the various arrangements and assemblies described above and illustrated in the drawings, the soil shares 4, the trash shares 2 and any secondary trash shares 6 or some of these are preferably pivotably mounted to take up alternative operating positions, upon reversal of the ploughing direction. It is to be understood that the scope of the invention is not limited to the preceding specific disclosures.

Claims: CLAIMS 1. In or for a plough a tool arrangement comprising a rotatably mounted trash share (2) with a cutting rim (43) set at an angle partly to penetrate soil to a pre¬ determined first depth and to impart rotation to the trash share as the arrangement is progressively moved along a soil surface in a towing direction (8) and a soil share (4) disposed behind and to one side of the trash share relative to the towing direction, the soil share being set at a different angle to the cutting rim (43) of the trash share (2) to penetrate the soil to a pre¬ determined second depth whereby the rotating trash share predominantly displaces trash and some soil to said one side and the soil share displaces further soil to cover the trash and create a furrow. 2. A tool arrangement according to Claim 1, wherein the second depth is greater than the first depth. 3. A plough frame sub-assembly adapted to be towed along a soil surface on which there is mounted a tool arrangement according to Claim 1 or 2. 4. A plough frame included a number of sub-assemblies according to Claim 3. 5. A plough frame or frame sub-assembly according to Claim 3 or 4, wherein each tool arrangement comprises several trash shares (2) and several soil shares (4). 6. A plough frame or frame sub-assembly according to Claim 5, wherein each tool arrangement further comprises one or more secondary trash shares (6) disposed to one side of the soil share or soil shares (4). 7. A plough frame or frame sub-assembly according to Claim 5 or 6 wherein one or more of the shares (2, 4, 6) is pivotably mounted to take up alternative operating positions when the towing direction is reversed. 8. A plough frame or frame sub-assembly according to Claim 5, 6 or 7 wherein each trash share (2) is a concave disc or has the configuration of a top hat. 9. A plough frame or frame sub-assembly according to Claim 5, 6, 7 or 8 wherein the axes of rotation (PI) of the trash shares (2) are inclined in relation to a vertical plane perpendicular to the towing direction (8). 10. A plough frame or frame sub-assembly according to Claim 9, wherein there are groups of trash shares (2) each with parallel rotational axes (PI, P2) and the axes of the groups of shares are inclined in different directions. 11. A plough frame or frame sub-assembly according to any one of Claims 5 to 9, wherein the trash shares (2) are adapted to rotate in a direction contrary to the action of the soil shares (4). 12. A method of cultivation or ploughing using a tool arrangement composed of at least one rotatable trash share (2) and at least one soil share (4) set at different working angles and comprising the steps of disposing a forward-most cutting rim (43) of the trash share (2) angled towards one side and slightly into the soil and disposing the soil share (4) rearwardly of the trash share (2) and moving the arrangement progressively over the area to be ploughed at sufficient speed whereby the trash share (2) is rotated by contact with the soil to remove and displace trash in an upper soil layer to one side and the soil share (4) follows in the path cleared by the trash share and displaces further soil in order to cultivate said soil with a reduced amount of trash therein.

Inventors: GENT ANTHONY, TAYLOR KENNETH FREDERICK, GENT, ANTHONY, TAYLOR, KENNETH, FREDERICK
Applicants: GENT ANTHONY, TAYLOR KENNETH FREDERICK, GENT, ANTHONY, TAYLOR, KENNETH, FREDERICK
Application year: 1993
Main classification: A01B17
IPC codes: A01B17, A01B21