GB2050782A - Plough - Google Patents

Abstract

A plough comprises a mulboard 12 for turning soil over into the adjacent furrow, a rotatable disc 21 for cutting the soil ahead of the mulboard to ease the passage of the mulboard and a dished rotatable disc 31 whose leading edge is aligned with that of the disc 21. The disc 31 deflects the top layer of soil cut by the disc 21 into the adjacent furrow before the mulboard turns the rest of the soil into the furrow. The rotation of the discs 21, 31 distributes wear uniformly around the periphery. <IMAGE>

Description

SPECIFICATION Plough This invention relates to ploughs. A plough comprises a mulboard which has a leading edge inclined in one direction and a trailing edge inclined in the other direction so that as the mulboard is drawn through the soil it turns the soil over. If the mulboard is drawn through the soil beside a furrow, it will turn the soil over into the furrow and leave a further furrow behind it. It is usual to provide a plurality of mulboards on a plough, in staggered formation, so that each mulboard turns soil over into the furrow left by the preceding mulboard.

The leading edge of the mulboard and its support present a fairly large cross-sectional area to be drawn through the soil, and if they are drawn through compacted soil, they tend to crumble the soil and build up a mound of soil in front of the leading edge. It is therefore usual to provide a cutting device in front of the mulboard which forms a slit in the soil through which the leading edge of the mulboard and its support can be drawn. This cutting device is usually in the form of a flat rotatable disc aligned with the top of the leading edge of the mulboard.

The turning-over action of the mulboard may only be sufficient to turn the soil over through about ninety degrees, so that weeds originally growing on the top surface of the soil are still exposed to the air and grow up the side of the soil turned over into the preceding furrow and quickly re-establish themselves. In order to ensure that weeds growing on the top surface of the soil to be ploughed are buried during the ploughing action, it has been proposed to provide a skimmer blade beside the cutting device in order to deflect the top layer of the soil into the preceding furrow before the mulboard turns over the lower layer into the furrow so that the original top surface of the soil is buried below the turned-over lower layer in the furrow.Such skimmer blades have the disadvantage that they wear very quickly, requiring frequent adjustment and replacement, and they also increase the drag of the soil against the plough.

It is an object of the present invention to provide a plough with a skimming device which is not subject to these disadvantages.

According to the invention there is provided a plough comprising a mulboard arranged to turn over soil into a furrow when drawn forwards through the soil, a rotatable disc mounted forwardly of the mulboard and aligned with the front end of the mulboard to cut a path through the soil for the mulboard and a dished rotatable disc mounted forwardly of the mulboard with its leading edge aligned with the front end of the mulboard and the leading edge of the first mentioned rotatable disc to deflect the top layer of soil into the furrow before the mulboard turns over the remainder of the soil.

The rotatable nature of the dished disc reduces the drag experienced by the plough, and the constantly changing leading edge of the disc presented to the soil reduces the wear it experiences. The dishing of the disc provides it with strength to deflect the top layer of soil into the furrow and enables it to present a leading portion in the vertical plane of forward movement while its rear portion is inclined to that plane in order to deflect the soil.

The dished disc is preferably mounted with its leading edge rearwardly of the leading edge of the first-mentioned disc and aligned therewith so that it acts on the top layer of soil which has already been cut by the first-mentioned disc. The dished disc is preferably mounted beside the first-mentioned disc.

An example of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view of a plough from the front and to one side, Figure 2 is a perspective view of the plough of Figure 1 from the one side, Figure 3 is a perspective view of the rear end of the plough from above and to the other side, and Figure 4 is a detail of the plough of Figure 1.

The plough illustrated in the drawings comprises a longitudinal frame 11 adapted to be mounted on a tractor (not shown) for drawing through the soil in the longitudinal direction. As shown most clearly in Figure 2, the plough comprises three mulboards 12 mounted in staggered formation on the frame 11.

Each mulboard 12 comprises a curved plate which is twisted along its length. The leading edge 13 of the mulboard 12 is approximately vertical at the top and curves outwardly at the bottom. The mulboard 12 twists along its length so that the top edge extends further in the outward direction relative to the bottom edge. As the mulboard 12 is drawn through the soil, the twisted shape causes the soil to be turned over.

At the bottom of the leading edge 13 of the mulboard 12, a ploughshare 15 is mounted to assist the cutting action of the mulboard into the com pacted soil. In front of the top edge of the leading edge 13 of the mulboard 12 is mounted a vertical flat disc 21 aligned with the top of the leading edge 13.

The disc 21 is mounted for rotation about its axis so that as the plough is drawn through the soil, the disc will rotate, clockwise as seen in Figures 1 and 2, to reduce drag and wear.

Beside the disc 21 is mounted a dished rotatable disc 31. As can be seen most clearly in Figure 3, the dishing of the disc 31 causes soil to be deflected from the plane of the disc 21 in the outwards direction of the mulboard 12. The disc 31 is only required to deflect the top layer of the soil, and so its lowest extent is higher than the lowest extent of the disc 21 and of the mulboard 12.

A disc 21 and 31 is provided for each mulboard 12, suitably aligned therewith.

The mulboard 12, disc 21 and the disc 31 are supported separately from the frame 11, the mulboard 12 by means of an arm 22 curved in the forward direction and supporting the mulboard 12 at its leading edge 13 and supporting the ploughshare 15. A bar 16 extends longitudinally back from the leading edge of the mulboard 12 and a rod 17 extends transversely from the bar 16to support the trailing edge of the mulboard 12. The discs 21 and 31 are mounted rotatably on arms 22 and 32 fixedly mounted on the frame 11.

The disc 31 acts on the top layer of soil which is a few inches deep, and since the centre of the disc must be above the general level of the soil, the diameter of the disc 31 should be at least eight inches and preferably between twelve and fourteen inches.

The reduced drag experienced by the discs, compared to other cutting and deflecting devices, can provide increased fuel economy or can increase the- number of furrows which can be ploughed buy a given tractor.

Claims (7)

1. A plough comprising a mulboard arranged to turn over soil into a furrow when drawn forwards through the soil, a rotatable disc mounted forwardly of the mulboard and aligned with the front end of the mulboard to cut a path through the soil for the mulboard and a dished rotatable disc mounted forwardly of the mulboard with its leading edge aligned with the front end of the mulboard and the leading edge of the first mentioned rotatable disc to deflect the top layer of soil into the furrow before the mulboard turns over the remainder of the soil.

2. A plough as claimed in claim 1 wherein the dished disc is mounted with its leading edge rear wardly of the leading edge of the first-mentioned disc and aligned therewith so that it acts on the top - layer of soil which has already been cut by the first-mentioned disc.

3. A plough as claimed in claim 1 or claim 2 wherein the dished disc is mounted beside the first-mentioned disc.

4. A plough as claimed in any one of claims 1 to 3 wherein the first-mentioned disc extends deeper than the dished disc.

5. A plough as claimed in any one of claims 1 to 4 comprising a plurality of mulboards arranged in staggered formation, each mulboard being provided with a said rotatable disc mounted forwardly thereof and a said dished disc.

6. A plough as claimed in any one of claims 1 to 5 comprising a ploughshare mounted at the bottom of the leading edge of the or each mulboard.

7. A plough substantially as herein described with reference to and as illustrated in the accom panying drawings.