BACKGROUND TO THE INVENTION Proper preparation of soil is an essential element of successful cultivation of plants and crops. This includes working and adequate mixing of soil to a sufficiently deep level in order to enhance the propagation of roots.

Ploughs are well known and widely used in preparing and cultivating ground for planting seeds or seedlings. Conventional ploughs have stationary shares or plough formations that are fixed to a frame. The frame is then moved, causing the ploughshares or plough formations to dislodge and overturn the soil. The ploughing depth and mixing efficiency obtained with this configuration is not always adequate, due to the fixed geometrical constraints and the limited cutting edge speed associated with this configuration.

An enhanced type of earth working system incorporates a rotating plough member, usually in the form of a rotating drum or rotating discs, from which plough formations extend. The rotating action of the plough member provides for more efficient ploughing as well as for enhanced mixing of soil. The depth of ploughing and mixing can furthermore be regulated should the rotating plough member be mounted on a pivotable arm. The rotating member is however often driven by a chain and sprocket type drive that can be unreliable given the harsh conditions that it is exposed to. The rotating drum and associated plough formations are furthermore prone to clogging due to moist soil encountered at deeper levels. The occurrence of clogging is furthermore exacerbated when the earth working system is used in soil having clay- type characteristics.

WO 02/21897 in the name of Jacobus Stofberg discloses an earth working apparatus consisting of at least one rotatable member that has a number of discs mounted thereon. The discs are spaced apart, and disposed parallel to one another, with each disc having a set of dislodging members for use in dislodging earth. The spacing apart of the discs result in gaps being formed between adjacent discs, thus resulting in the set-up being susceptible to clogging and to rocks and other solids getting stuck in the gaps. The obstruction of the gaps between the discs adversely affects the efficiency of the apparatus as the displacement of soil is hampered thereby. The design of the disc and dislodging member interface is further of such a nature that rocks and other solids can easily get stuck between the dislodging member and the disc, thus further affecting the working of the apparatus.

OBJECT OF THE INVENTION ft is an object of this invention to provide an earth working apparatus that, at least partially, alleviates the abovementioned disadvantages.

SUMMARY OF THE INVENTION According to this invention there is provided an earth working apparatus comprising at least one rotatable member having a plurality of discs mounted thereon, the discs being spaced apart and situated parallel to each other so as to define gaps between adjacent discs, ploughing members extending from the discs, and a de-clogging member configured to prevent the obstruction of the gaps.

A further feature provide for the rotating member to be a rotating drum.

Another feature of the invention provide for the de-clogging member to be stationary mounted relative to the rotating drum, and for the de-clogging member to include a support beam mounted longitudinally relative to the drum.

Further features provide for the support beam to have baffle plates extending there from ; for the baffle plates to extend into the gaps between the discs of the drum; for the baffle plates to be dimensioned so as to closely resemble the cross-sectional profile of the gaps; for the baffle plates to have bottom ends that terminates adjacent to an outer surface of the drum; and for the baffle plates to form an obtuse angle with an outside surface of the drum.

A yet further feature provides for a plurality of ploughing members to be mounted on the periphery of the discs.

Further features provide for the ploughing members to have connection ends for connection to the discs and cutting ends for engaging the soil; for the ploughing members to be of a tapered configuration from the connection ends to the cutting ends; for connection extensions to extend outwardly from the discs; for the ploughing members to be connected to the connection extensions; and for the ploughing members to be orientated substantially tangentially relative to the discs.

Another feature of the invention provides for the ploughing members to have wing members extending laterally there from.

Another aspect of the inventions provide for the rotating drum to be driven by a motor operatively connected thereto.

The motor may be a hydraulic motor, and the hydraulic motor may be driven by pumping pressurised fluid from a fluid source to the motor.

It is furthermore provided for the earth working apparatus to be connectable to a connection arm that connects the apparatus to a vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a schematic three-dimensional view of the earth working apparatus according to the invention; Figure 2 shows a perspective view of the de-clogging member; Figure 3 shows a cross-sectional side view of the earth working apparatus of Figure 1; Figure 4 shows a perspective view of the discs and ploughing members of the earth working apparatus of Figure 1; and Figure 5 is a perspective view of an alternative embodiment of a ploughing member in accordance with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings, in which like numerals indicate like features, an earth working apparatus according to the invention is indicated by reference numeral 10.

According to this invention the earth working apparatus includes at least one rotatable member in the form of a drum 14 having a number of discs 15 and ploughing members 32 connected thereto, and a de-clogging member 16 configured to prevent the obstruction of gaps between the discs.

Referring to Figure 1 the earth working apparatus 10 is shown connected to a vehicle 50 for providing forward movement of the earth working apparatus 10. The apparatus is connected to the vehicle by means of a connecting arm 48 that can pivot about an axis on the vehicle in order to control the depth displacement of the apparatus 10. Two hydraulic cylinders 49 are attached to the connecting arm 48, for controlling the pivotal movement of the arm 48 and thus earth working apparatus 10 relative to the vehicle 50.

The earth working apparatus 10 comprises a drum 14 having a plurality of annular discs 15 mounted thereon. Ploughing members 32 extend from the annular discs 15. The discs 15 are positioned substantially parallel to one another so as to result in annular gaps being formed between adjacent discs 15.

Figure 4 shows an embodiment of the discs 15 and ploughing members 32 in more detail. The discs are of annular configuration, thus enabling the discs to be mounted on the drum (not shown). The discs may include connection extensions 30 extending outwardly from the discs for receiving the ploughing members 32. Each ploughing member 32 has a connection end 34 and a cutting end 36, and each ploughing member tapers from the connection end towards the cutting end. The ploughing members are mounted substantially tangentially relative to the outer periphery of the discs, with the cutting ends pointing in the direction of rotation. In other embodiments the ploughing members may be mounted substantially perpendicular relative to the outer peripheries of the discs (as is shown in figure 1), or may be angularly displaced between tangential and perpendicular orientations relative to the discs (not shown).

The discs further need not include the connection extensions 30, and the ploughing members 32 may be directly connected to peripheral zones of the discs.

A de-clogging member 16, shown in figure 2, is attached to the connecting arm 48, and is stationary relative to the rotating drum 14. The de-clogging member includes extensions 20 that extend from a support structure 22, said extensions being aligned with the gaps between the discs 15. The support structure 22 is disposed substantially parallel relative to the axis of rotation of the drum 14. A mounting plate 24 is furthermore attached to the support structure 22 for mounting the de-clogging member 16 to the connecting arm 48.

A plurality of baffle plates 28 are connected to the extensions 20 extending from the support structure 22. These baffle plates are configured and dimensioned to fit in the gaps between the spaced-apart discs 15 mounted on the drum 14. If viewed in cross-section, as shown in Figure 3, it can be seen that the baffle plates 28 are angularly displaced from a perpendicular orientation relative to the outside surface of the drum 15. The drum, as viewed in Figure 3, rotates in an anti-clockwise direction, and the baffle plates 28 prevent build-up of soil and other obstructions in the gaps between the discs during rotation. The baffles 28 may alternatively be orientated substantially perpendicular relative to the drum.

A further embodiment of a ploughing member 32 in accordance with the invention is shown in figure 5. The ploughing member 32 includes a connection end 34 and a cutting end 36, and the ploughing member tapers down in cross-section from the connection end towards the cutting end so as to facilitate efficient dislodging of soil.

The connection end 34 of the ploughing member 32 includes apertures 37 for connecting the ploughing member to the connection extensions 30 extending from the discs 15. The ploughing member 32 in addition includes two opposed wing members 35 that extend from sides of the ploughing member, thus further increasing the dislodging area of the ploughing member.

The inventor believes hat the apparatus 10 can be used to solve some of the problems associated with known technology. The apparatus can be used to work soil to a sufficiently deep level, whilst the de-clogging member will prevent a build-up of soil and rocks in the gaps between the discs. The de-clogging member will also improve the degree of mixing obtained while working the soil. It has been shown during field tests that the de-clogging member substantially increases the efficiency of the apparatus.

It will be appreciated that the examples shown are only some embodiments of the invention, and many variations in detail are possible without departing form the scope of the invention. For example, the connecting arm 48 can be of fork-shaped in order to engage the drum 14 from the sides, and the ploughing members may be of any configuration wherein at least part of each ploughing member extends beyond the periphery of the discs.