AU2006315092A1

AU2006315092A1 - Ground aerator

Info

Publication number: AU2006315092A1
Application number: AU2006315092A
Authority: AU
Inventors: Greg Cali; Salvatore Cartellone
Original assignee: BLADE RUNNA Pty Ltd
Current assignee: BLADE RUNNA Pty Ltd
Priority date: 2005-11-17
Filing date: 2006-11-17
Publication date: 2007-05-24
Also published as: WO2007056819A1

Description

WO 2007/056819 PCT/AU2006/001731 -1 GROUND AERATOR BACKGROUND TO THE INVENTION 5 This invention relates to devices for aeration of ground areas such as lawns, and in particular to an aeration device for attachment to existing equipment such as a lawn mower. A wide range of aeration devices exist, such as described in US 5,101,910 and US 10 4,899,828. In general terms these devices have a roller assembly with a series of spikes which penetrate the ground. The spikes create holes which allow fresh air to circulate more effectively through the top soil. Reference to any prior art documents in this specification is not an acknowledgment that the documents form part of the common general knowledge. 15 The known aeration devices are generally not designed for attachment to a lawn mower, and generally lack one or more suitable characteristics. In particular, many of the existing devices do not permit a convenient height adjustment and do not use ground spikes of an optimum shape. Many of the aerator devices also cause significant damage to the surface 20 of the lawn and cannot be used on a regular basis to renew the aeration effect. SUMMARY OF THE INVENTION It is an object of the invention to provide an improved aerator, or at least to provide an 25 alternative to existing aerator systems. In one aspect the invention resides in A lawn mower, including: cutting blades, an engine which drives the cutting blades, and a set of ground wheels, mounted together on a chassis, and an aerator attached or attachable to a forward portion of the chassis, wherein the 30 aerator includes: a roller assembly having at least one roller with an axle and a plurality of WO 2007/056819 PCT/AU2006/001731 -2 radial ground spikes, each spike having a holding portion which engages the axle and holds the spike in a fixed orientation on the roller. In another aspect the invention resides in an aerator device for a lawn mower, including: a 5 frame attachable to the equipment, a roller assembly having at least one roller with an axle and a plurality of radial spikes, and an adjustment mechanism which determines the height of the roller assembly in relation to the frame, wherein the adjustment mechanism includes a pair of parallel plates in frictional contact through a bearing and fastened together at a pivot, one plate being attached to the roller assembly and the other plate attached to the 10 frame. In a further aspect the invention resides in an aerator device for a lawn mower or similar equipment, including: a frame attachable to the equipment, and a roller assembly having at least one roller with an axle and a plurality of radial spikes, wherein each spike has a shape 15 including two concave edges which join to form a point for penetrating the ground. In a still further aspect the invention resides in an aerator device for a lawn mower or similar equipment, including: a frame attachable to the equipment, and a roller assembly mounted on the frame having at least one roller with an axle and a plurality of radial 20 spikes, wherein each spike has a holding portion which engages the axle and holds the spike in a fixed orientation on the roller. The invention may also be said to reside in any alternative combination of features that are indicated in this specification. All equivalents of these features are included whether or 25 not explicitly set out. LIST OF FIGURES Preferred embodiments of the invention will be described with respect to the drawings, of 30 which: Figure 1 shows an aeration device attached to a lawn mower, WO 2007/056819 PCT/AU2006/001731 -3 Figure 2 shows a roller assembly for the aeration device, Figures 3a, 3b give front and end views of the assembly, Figure 4 is an exploded view of roller components, and Figure 5 shows alternative roller components. 5 DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings it will be appreciated that the invention may be implemented in a variety of different ways. This description is given by way of example only. 10 Figure 1 shows an aerator device 10 attached to a lawn mower. The device may be provided for fitting to an existing mower or similar equipment, or may be permanently incorporated in the equipment. The device is preferably fitted at the front of the equipment and is independently adjustable in height. A removable shield 11 and a handle 12 for 15 manual adjustment of the device are shown in this view. The lawn mower in this example has a conventional construction, including a chassis 5 with four wheels 6, an engine 7 and cutting blades (not shown) which are driven by the engine, but may take a variety of structures. The mower is typically but not necessarily pushed by hand. 20 Figure 2 shows internal components of the device 10 in Figure 1, without the shield 11 and without an external part of the handle 12. The device includes a frame 20 and two coaxial rollers 21 each having multiple teeth or spikes 22. The rollers are mounted on the frame which may in turn be mounted on the mower by way of attachment bars 23. These bars may also serve to attach the shield 11. Each roller supports a sequence of spikes spaced 25 apart by separators 24 forming a roller assembly. Handle 12 is connected to each end of the roller assembly in this example. Many variations are possible in the numbers and arrangement of the rollers, spikes and other components. The components are generally made of steel. 30 In Figure 2, a height adjustment mechanism is indicated to allow adjustment of the spikes in relation to frame 20, and thereby to enable variation in the depth of ground penetration WO 2007/056819 PCT/AU2006/001731 -4 by the spikes 22. Brackets 25 in the form of plates are provided at each end of the roller assembly. Frame portions 27, also typically plates, are provided parallel to respective plates 25, and generally in contact. Each pair of plates 25, 27 is able to mutually rotate about a pivot connection 26, generally by manual urging of the handle 12. A bearing 28 5 such as a pin or ball on each bracket 25 engages one of a series of apertures or indents 29 on the respective frame portion 27, and secures the roller assembly in a required position about the pivot points. Figures 3a and 3b give plan and end views of the frame and roller assembly shown in 10 Figure 2. Each roller 21 has a series of ground spikes 22 mounted in a helical pattern, at angular separations of 60 degrees. Other patterns and separations are possible. The pattern is intended to provide a regular spacing of aeration holes and also to enable relatively uniform resistance to movement of the device over the ground. The rollers each have the same pattern of spikes in this example. 15 The spikes preferably have a planar structure with concave edges 31, 32 which meet in a point 33. It is considered that concave edges are more effective than convex or straight edges. Typically the radius of each curved edge is about twice the length of the spike, measured from the centre of the axle, although a range of +/-50% is considered acceptable. 20 The planar form of the spike creates a small slot in the ground to a depth of several centimetres or more, and is intended to minimise any additional damage to the surface of the lawn. Figure 3a also shows the adjustment mechanism in cross section. A ball bearing is 25 contained by a main aperture in the plate 25 at either or both ends of the roller assembly. Plate 27 on one side of each plate 25 and plate 30 on the other side of plate 25 retain the bearing within the aperture. Plate 27 typically has a single smaller aperture or indent adjacent the main aperture in plate 25 for this purpose. Plate 27 includes the series of apertures 29 to provide the range of adjustments. Other adjustment mechanisms may also 30 be provided, such as a pin which engages an aperture in plate 25.

WO 2007/056819 PCT/AU2006/001731 -5 Figure 4 shows components of the rollers 21 in Figure 3 in an exploded format. Spikes 22 and spacers 24 may be retained on the rollers in a variety of ways. Each roller includes an axle 40 with a shaped outer surface, provided by a hexagonal cross section in this example. A range of angular or semi-angular cross sections may be provided. Pin 41 on one roller 5 engages cavity 42 on the other roller by way of bearings 43 to maintain the rollers in coaxial alignment. Nuts 47 located between and at each end of the roller assembly fasten the rollers together and to the frame 20. Figure 5 shows an alternative arrangement of components for retaining the spikes and 10 spacers on the rollers. A groove 50 and circlip 51 are provided at each end of each axle. The circlips are fitted to the grooves once the spikes and spacers have been loaded onto the axles. In this view the groove and circlip combinations can only be seen at the left hand ends of the axles. 15 Figures 4 and 5 show how spikes 22 and separators 24 are mounted on the axles 40 and interact with their outer surfaces. This holds the spikes in fixed patterns on the rollers. Each spike has an aperture portion 45. An inner perimeter 46 of the aperture portion matches the outer surface of the respective axle. During assembly of the rollers, the spikes are individually oriented so that the sharp portions 44 follow the helical pattern described 20 above.

Claims

1. A lawn mower, including: cutting blades, an engine which drives the cutting blades, and a set of ground 5 wheels, mounted together on a chassis, and an aerator attached or attachable to a forward portion of the chassis, wherein the aerator includes: a roller assembly having at least one roller with an axle and a plurality of radial ground spikes, each spike having a holding portion which engages the axle and holds the 10 spike in a fixed orientation on the roller.

2. A mower according to claim 1 wherein the aerator further includes a height adjustment mechanism formed by at least two parallel plates, one plate containing a bearing in contact with the other plate. 15

3. A mower according to claim 1 wherein each ground spike has two concave edges which meet at a point.

4. An aerator device for a lawn mower, including: 20 a frame attachable to the equipment, a roller assembly having at least one roller with an axle and a plurality of radial spikes, and an adjustment mechanism which determines the height of the roller assembly in relation to the frame, 25 wherein the adjustment mechanism includes a pair of parallel plates in contact through a bearing and fastened together at a pivot, one plate being attached to the roller assembly and the other plate attached to the frame.

5. An aerator according to claim 4 wherein the bearing is a ball contained by an 30 aperture in one plate and moved between consecutive indents on the other plate by manual pressure applied transversely to the plates. WO 2007/056819 PCT/AU2006/001731 -7

6. An aerator according to claim 5 further including a third plate in parallel with and adjacent to the one plate containing the bearing but opposite to the other plate containing the indents, thereby urging the bearing into the indents. 5

7. An aerator device for a lawn mower or similar equipment, including: a frame attachable to the equipment, and a roller assembly having at least one roller with an axle and a plurality of radial spikes, 10 wherein each spike has a shape including two concave edges which join to form a point for penetrating the ground.

8. An aerator according to claim 7 wherein the concave edges of each spike have a radius of curvature which is approximately twice the length of the spike. 15

9. An aerator according to claim 7 wherein the shape of each spike is planar and includes an aperture which matches the cross section of the axle.

10. An aerator device for a lawn mower or similar equipment, including: 20 a frame attachable to the equipment, and a roller assembly having at least one roller with an axle and a plurality of radial spikes, wherein each spike has a holding portion which engages the axle and holds the spike in a fixed orientation on the roller. 25

11. A device according to claim 10 further including a plurality of separators located between the spikes to provide a predetermined spacing of spikes along the axle.

12. A device according to claim 10 wherein the holding portion of each spike includes 30 an aperture which surrounds the axle and which matches the cross section of the axle. WO 2007/056819 PCT/AU2006/001731 -8

13. A device according to claim 10 wherein the axle has an angular cross section, such as hexagonal, which prevents rotation of the spikes about the axle.

14. A device according to claim 10 wherein the spikes are distributed with a helical 5 variation along the roller.

15. A device according to claim 10 wherein the roller assembly has two rollers joined end to end on a common axis. 10

16. A device according to claim 10 wherein the roller assembly includes an adjustment mechanism which determines the height of the roller above ground.