PLOUGH

This invention relates to a plough suitable for inverting only a top layer of soil, for example to bury stalks of plants left after harvesting.

A crop which is increasingly grown in the early part of the year in Europe is oil seed rape, and after the early harvest of this crop, the ground may be reused for a second crop of another type. Harvesting of oil seed rape leaves thick stalks containing a high degree of sap which prevents their being burnt. It is therefore desirable to turn the earth so as to bury these stalks. However, full depth ploughing of the soil is too time-consuming and costly a process to be attractive to farmers, especially since full ploughing will have taken place before the rape was sown. Additionally, the harvesting of cereals leaves stubble which is desirably buried rather than burnt, since the practice of straw-burning is becoming increasingly objected to. This is difficult to achieve with conventional cultivators or ploughs.

FR-A-2,264,468 discloses a plough, mainly used in vineyards, having the features corresponding to the preamble of claim 1. DE-C-1,252,957 discloses a plough with a single beam and plough blades on it. Rotary members which rotate about horizontal shafts are provided above and before each plough blades.

The present invention provides a plough which may enable such soil turning to be undertaken more easily.

According to the invention, there is provided a plough having at least one pair of generally diverging support beams, each beam carrying a plurality of plough blades, the blades on each beam being arranged to turn earth and to move it towards the other beam, wherein the support beams diverge in a direction away from the front of the plough, characterised in that a pair of rotary members, are provided at the forward end of the diverging support beams in a central position and in which the rotary members are rotated about generally downwardly extending shafts in opposite relative directions to propel earth in generally left and right side ways directions into the path of the plough blades which fill in the earth removed by the rotary members.

In a preferred embodiment, scraping blades disc harrows, or any other surface-acting cultivating tools may be attached to the rear of the plough so that such tools follow between the pairs of beams to redistribute displaced earth so as to leave a generally flat surface. Preferably the tools are arranged to push earth back into the furrows formed by the two outermost (and rearmost) blades.

The plough of the invention enables a large area to be cultivated in one pass of the plough without creating difficulties of balance which may be experienced with a conventional reversible plough of great length. The plough achieves complete inversion of the top player of the earth, for example to a depth of 125 mm, with, consequently, a much lower power requirement than a conventional deep plough.

Reference is made to the drawings, which show a plough in accordance with a preferred embodiment of the invention, and in which:

• Figure 1 is a perspective view; and
• Figure 2 is a top plan view.

The plough comprises a generally horizontal wheeled frame 1 carrying a conventional draw bar arrangement 2. Extending obliquely across the main frame 1 are two support beams 4 and 5, which diverge away from the draw bar. Each beam 4 and 5 carries three conventional plough blades 6 arranged to turn earth and to move it inwardly of the frame towards the other beam of the pair. It will be appreciated that the frame 1 may readily be made larger so as to accommodate a larger number of blades on each support beam.

A pair of rotating spinners 7 are mounted on the front of the frame 1 between the beams 4 and 5. The spinners 7 are driven from a gear-box 8, in turn powered by a power take-off shaft of the towing tractor, and each has a plurality of rods extending from its periphery so as to define a generally frusto-conical shape, with the rods intermeshing as they enter the soil. One spinner can be mounted ahead of the other by a small degree for greatest efficiency of operation. The axes of rotation of the spinners preferably make an angle of approximately 45° therebetween. The spinners are rotated in opposite directions as indicated by the arrows A in Figure 2, so as to propel earth outwardly into the path of the plough 6 on each side.

It will be appreciated that any rotary member capable of propelling earth outwardly across the paths of the plough blades may be used in place of the spinners. Additionally, the gear-box 8 may be adaptable to give different drive ratios to ensure full and even distribution of soil of different types.

It has been found that a plough of the type described with reference to the drawings gives a very thorough inversion of the top layer of the earth, sufficient to bury completely any stalks left after harvesting, e.g. of oil seed rape, with on a single pass, but a ridged surface may be left at the outer extremities of the frame, and it is therefore preferred to attach to the rear ends of the frame a series of scraper blades (not shown) to urge earth back into the trenches or furrows left at the outer edges of the plough. Many different cultivating tools are available which could be used in place of the scraper blades to divert soil from the ridges into the trenches or furrows. No further working of the soil is then required before further sowing or planting takes place.