IE20150273A1 - Apparatus for aerating grassland - Google Patents

Abstract

An apparatus for aerating grassland comprising a frame adapted to be attached to a vehicle, a plurality of vertically arranged cutting discs mounted on the frame for forming fissures in the ground, each cutting disc mounted at a distal end of a respective cantilevered arm, each respective cantilevered arm being pivotally mounted on the frame to permit independent vertical displacement of each disc, wherein each cantilevered arm is associated with a respective biasing means acting against the respective arm to bias the respective disc mounted thereon in a downwards direction with respect to the frame. <Figure 1>

Description

Compaction of grassland is a common problem caused by the movement of livestock and heavy machinery on the ground. Compaction reduces the grazing potential of the grassland. Not only is drainage and root development adversely affected by compaction of the ground, but the ability of the grass to utilise fertiliser is also affected. A lack of oxygen in the soil around the roots of the grass means the availability of mineralised Nitrogen from organic material in the soil is diminished. Furthermore, slurry applied to compacted grassland will not be absorbed readily, leading to run off into waterways.

Prior art devices for aerating grassland typically comprise spiked rotors arranged to cut into the ground (such as that disclosed in US 3,993,143) and/or tines which extend laterally through the ground beneath the surface to lift and loosen the soil (such as that disclosed in GB 2 118 411). However, such prior art attempts to aerate grassland have encountered problems of unduly damaging or disturbing the surface growth of grass and of bringing stones and other material to the surface, which can cause damage to mowers used to cut the grass during harvesting for silage unless collected.

According to the present invention there is provided an apparatus for aerating grassland comprising a frame adapted to be attached to a vehicle, a plurality of vertically arranged cutting discs mounted on the frame for forming fissures in the ground, each cutting disc being mounted at a distal end of a respective cantilevered arm, each respective cantilevered arm being pivotally mounted on the frame to permit independent vertical displacement of each disc, wherein each cantilevered arm is associated with a respective biasing means acting against the respective arm to bias the respective disc mounted thereon in a downwards direction with respect to the frame.

In one embodiment said plurality of discs are mounted in two or more rows, wherein the discs in a leading row are laterally offset with respect to the discs in a trailing row such that the discs in the trailing row are interposed between the discs in the leading row.

Preferably each disc has a substantially circular profile. Preferably each disc is aligned with the normal direction of travel of the apparatus. Each disc may be mounted on the respective cantilevered arm to be freely rotatable. In one embodiment each disc may be rotatably mounted on a transversely extending stub axle provided at a distal end of the respective cantilevered arm.

In one embodiment each biasing means may comprise a pneumatic or hydraulic ram adapted to bias the respective arm, and the respective disc mounted thereon, in a downwards direction with respect to the frame. The pneumatic or hydraulic rams may be coupled to one or more accumulators containing a compressible fluid, wherein the pressure within the or each accumulator may be varied to adjust the biasing force exerted by the rams coupled thereto.

In one embodiment the biasing means may each comprise a hydraulic ram, said rams being coupled to a common accumulator comprising a reservoir containing a moveable wall or piston dividing the reservoir into a first chamber on a first side of said moveable wall or piston and a second chamber on a second side of said moveable wall or piston, said first chamber containing hydraulic fluid and being in communication with an extend line of each ram, said second chamber containing gas under pressure, wherein the pressure of the gas in said second chamber may be adjusted to vary the biasing force exerted by each ram on the respective cantilevered arm upon which the respective ram acts.

Preferably each cantilevered arm is provided with means to raise the arm and associated cutting disc to a raised inoperative position when the apparatus is not in use, for example during road transport. The lifting means of each cantilevered arm may be defined by the respective ram defining the biasing means of the respective cantilevered arm, said ram comprising a double acting ram.

Each biasing means may comprise or incorporate a spring adapted to bias the respective cantilevered arm, and associated disc, in a downwards direction.

In one embodiment a height adjustment roller may be mounted on the frame for adjusting the cutting depth of the discs. Preferably the height of the roller is adjustable with respect to the frame to adjust the cutting depth of the discs. The height of the roller may be adjustable by means of an actuator. Such actuator may comprise a hydraulic ram. Preferably the height adjustment roller is mounted at a rear end of the frame, behind the discs in the normal direction of motion of the apparatus. The roller may be provided with a plurality of spikes or other projections extending from an outer surface thereof.

Preferably the frame of the apparatus is adapted to be mounted on a three point linkage of a vehicle.

In one embodiment each disc may be dimensioned to achieve a ground penetration of at least 200mm. The diameter of each disc may be approximately 750mm. Each disc may have a width of approximately 12mm.

Preferably each disc has a sharpened peripheral cutting edge. Each disc may have a serrated peripheral cutting edge.

In one embodiment, each cantilevered arm may comprise a trailing arm having a leading end pivotally mounted on the frame and a trailing end upon which a respective cutting disc is mounted. Alternatively, each cantilevered arm may comprise a leading arm having a rear end pivotally mounted on the frame and a forward end upon which a respective cutting disc is mounted.

The cutting blades of the apparatus of the present invention cut through the compacted layers of soil to open up fissures for better drainage, more efficient use of nutrients and healthier grass, without removing or lifting any significant amounts of soil or grass from the ground. The use of the apparatus of the present invention will boost grass yield, reduce fertiliser expense, and will improve slurry matter retention and nutrient uptake by roots.

An apparatus for aerating grassland in accordance with an embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which :- Figure 1 is a side view of an apparatus for aerating grassland in accordance with an embodiment of the present invention; and Figure 2 is a plan view of the apparatus of Figure 1.

As illustrated in the drawings, an apparatus for aerating grassland in accordance with an embodiment of the present invention comprises a frame 2 having suitable mounting points 4 to enable the apparatus to be mounted on the three point linkage of a vehicle, such as a tractor. Two rows of vertically mounted cutting discs 6,8 are mounted on the frame 2 for cutting continuous fissures or cuts into the ground 1 to a depth of approximately 240mm, cutting through and beneath the compacted upper layer of soil in order to enhance drainage and allow oxygen to enter the soil around the roots of the grass.

As shown in Figure 2, there are nine cutting discs in total, five discs 6 in a first or leading row and four discs 8 in a second or trailing row. The discs 8 in the second row are laterally offset from the discs 6 in the first row such that the discs of the second row 8 are interposed between the discs 6 of the first row. It is envisaged that more or less discs may be provided, either in a single row or in multiple rows. However, the provision of two rows of laterally offset discs provide a particularly advantageous fissure spacing while providing sufficient room for the disc mounting hardware.

Each cutting disc 6,8 may comprise a circular disc of approximately 750mm diameter and having a thickness of approximately 12mm, with a sharpened peripheral cutting edge.

As can be seen in the drawings, each cutting disc 6,8 is independently mounted on the frame via a respective cantilevered trailing arm 10, pivotally mounted at a forward end thereof to the frame 2 for pivotal movement about a horizontal axis such that each cutting disc 6,8 is independently vertically displaceable with respect to the frame 2. This allows each cutting disc 6,8 to be deflected upwardly should the disc encounter an obstacle in the soil, such as a large stone. Each trailing arm 10 may be arranged to provide a range of vertical travel for each cutting disc 6,8 of approximately 300mm.

Each trailing arm 10 may have a curved substantially horizontally extending leading section 12 pivotally coupled to the frame 2 via a suitable bearing assembly, and a rearwardly and downwardly extending trailing section 14 having a stub axle 16 extending transversely from a distal end thereof upon which the respective cutting disc 6,8 is mounted via a suitable bearing assembly such that the respective cutting disc 6,8 is freely rotatable about a respective horizontal central axis.

A respective hydraulic ram 18 acts between the frame 2 and each trailing arm 10, preferably coupled to the curved leading section 12 of the respective arm 10, biasing each cutting disc 6,8 downwardly away from the frame 2 into the ground 1. In the embodiment shown, the extend line of each ram 18 is coupled to a common accumulator (not shown), comprising a reservoir having a moveable wall or piston dividing the reservoir into a first chamber containing hydraulic fluid communicating with the extend line of each ram and a closed second chamber containing gas (for example Nitrogen) under pressure.

The compressible gas contained in the second chamber of the accumulator acts as a resilient spring acting against the moveable wall or piston, to provide a biasing force acting to extend each ram 18 and thus bias each cutting disc 6,8 downwardly into the soil. The biasing force provided by each ram 18 can be adjusted by adjusting the pressure within the second chamber of the accumulator. In this way, the downwards biasing force acting against each cutting disc 6,8 can be adjusted to suit the soil conditions of the grassland to be aerated by the apparatus.

Each ram 18 may also be provided with or associated with a spring (not shown), acting to spring load each cutting disc 6,8 in a downwards direction. It is also envisaged that the rams 18 may be replaced by suitable springs to bias the trailing arms 10, and hence the cutting discs 6,8, in a downwards direction. Alternatively pneumatic rams may be provided for acting against the trailing arms 10 to bias the cutting discs 6,8 in a downwards direction.

In order to control the cutting depth of the cutting discs 6,8, a transversely extending roller 20 is mounted on the frame 2, preferably at a rear end of the frame 2. In the embodiment shown the drawings, the roller 20 is mounted on a sub-frame 22 coupled to the main frame 2 by a pair of rearwardly extending lateral arms 24,26 pivotally mounted on either side of the frame 2, a hydraulic ram 28 acting between the frame 2 and the sub-frame 22 to control the height of the roller 20 with respect to the main frame 2 of the apparatus.

The roller 22 may be provided with spikes 30 extending from the outer surface thereof to further aerate the surface layer of the soil of the grassland over which the apparatus is traversed.

Actuating means may be provided for raising the trailing arms to raise the cutting discs with respect to the frame to allow the apparatus to be transported on the road when not in use. In one embodiment the rams 18 used to bias the cutting discs 6,8 downwardly away from the main frame 2 may comprise double acting rams capable of selectively raising the trailing arms 10 and cutting discs 6,8 with respect to the frame 2 by means of a suitable hydraulic control system.

The invention is not limited to the embodiment(s) described herein but can be amended or modified without departing from the scope of the present invention.

Claims (5)

Claims

1. An apparatus for aerating grassland comprising a frame adapted to be attached to a vehicle, a plurality of vertically arranged cutting discs mounted on the frame for forming fissures in the ground, each cutting disc being mounted at a distal end of a respective cantilevered arm, each respective cantilevered arm being pivotally mounted on the frame to permit independent vertical displacement of each disc, wherein each cantilevered arm is associated with a respective biasing means acting against the respective arm to bias the respective disc mounted thereon in a downwards direction with respect to the frame.

2. An apparatus as claimed in claim 1, wherein said plurality of discs are mounted in two or more rows, wherein the discs in a leading row are laterally offset with respect to the discs in a trailing row such that the discs in the trailing row are interposed between the discs in the leading row.

3. An apparatus as claimed in any preceding claim, wherein each disc has a substantially circular profile.

4. An apparatus as claimed in any preceding claim, wherein each disc is aligned with the normal direction of travel of the apparatus. 5. An apparatus as claimed in any preceding claim, wherein each disc is mounted on the respective cantilevered arm to be freely rotatable. 6. An apparatus as claimed in claim 5, wherein each disc is rotatably mounted on a transversely extending stub axle provided at a distal end of the respective cantilevered arm. 7. An apparatus as claimed in any preceding claim, wherein each biasing means comprises a pneumatic or hydraulic ram adapted to bias the respective arm, and the respective disc mounted thereon, in a downwards direction with respect to the frame. 8. An apparatus as claimed in claim 7, wherein said pneumatic or hydraulic rams are coupled to one or more accumulators containing a compressible fluid, wherein the pressure within the or each accumulator may be varied to adjust the biasing force exerted by the rams coupled thereto. 9. An apparatus as claimed in claim 8, wherein said biasing means each comprise a hydraulic ram, said rams being coupled to a common accumulator comprising a reservoir containing a moveable wall or piston dividing the reservoir into a first chamber on a first side of said moveable wall or piston and a second chamber on a second side of said moveable wall or piston, said first chamber containing hydraulic fluid and being in communication with an extend line of each ram, said second chamber containing gas under pressure, wherein the pressure of the gas in said second chamber may be adjusted to vary the biasing force exerted by each ram on the respective cantilevered arm upon which the respective ram acts. 10. An apparatus as claimed in any preceding claim, wherein each cantilevered arm is provided with means to raise the arm and associated cutting disc to a raised inoperative position when the apparatus is not in use, for example during road transport. 11. An apparatus as claimed in claim 10, when dependent upon any of claims 7 to 9, wherein said lifting means of each cantilevered arm is defied by the respective ram defining the biasing means of the respective cantilevered arm, said ram comprising a double acting ram. 12. An apparatus as claimed in any preceding claim, wherein each biasing means comprises or incorporates a spring adapted to bias the respective cantilevered arm, and associated disc, in a downwards direction. 13. An apparatus as claimed in any preceding claim, wherein a height adjustment roller is mounted on the frame for adjusting the cutting depth of the discs. 14. An apparatus as claimed in claim 13, wherein the height of the roller is adjustable with respect to the frame. 15. An apparatus as claimed in claim 14, wherein the height of the roller is adjustable by means of an actuator. 16. An apparatus as claimed in claim 15, wherein said actuator comprises a hydraulic ram. 17. An apparatus as claimed in any of claims 13 to 16, wherein said height adjustment roller is mounted at a rear end of the frame, behind the discs in the normal direction of motion of the apparatus. 18. An apparatus as claimed in any of claims 13 to 17, wherein the roller is provided with a plurality of spikes or other projections extending from an outer surface thereof. 19. An apparatus as claimed in any preceding claim, wherein the frame is adapted to be mounted on a three point linkage of a vehicle. 21. An apparatus as claimed in any preceding claim, wherein each disc is dimensioned to achieve a ground penetration of at least 200mm. 22. An apparatus as claimed in claim 21, wherein the diameter of each disc is approximately 750mm. 23. An apparatus as claimed in any preceding claim, wherein each disc has a width of approximately 12mm. 24. An apparatus as claimed in any preceding claim, wherein each disc has a sharpened and/or serrated peripheral cutting edge. 25. An apparatus as claimed in any preceding claim, wherein each cantilevered arm comprising a trailing arm having a leading end pivotally mounted on the frame and a trailing end upon which a respective cutting disc is mounted. 26. An apparatus as claimed in any of claims 1 to 14, wherein each cantilevered arm comprising a leading arm having a rear end pivotally mounted on the frame and a forward end upon which a respective cutting disc is mounted.

5. 27. An apparatus for aerating grassland substantially as herein described with reference to the accompanying drawings.