The present invention relates to cutting apparatus, and to methods of manufacture and operation of such apparatus. Embodiments of the present invention are particularly suitable for use in trimming grass and similar vegetation.

Many homeowners own a variety of apparatus for maintaining and caring for their lawns, with each device having a particular application. For instance, homeowners may own both a lawn mower and machine for trimming small areas of grass, such as a strimmer. The lawn mower is used for cutting relatively large areas of the lawn, using a rotary blade. Most lawn mowers collect the grass that is cut.

Strimmers or the like are typically used to cut smaller areas of grass, and particularly those areas that are inaccessible to mowers (e.g. within a small enclosed space or on a slope). Strimmers may also be utilised to cut grass that is too long to cut with a lawn mower, or grass that requires cutting adjacent to a lawn boundary or obstacle. Strimmers are typically electrically powered grass trimmers, that utilise a nylon cutting cord which rotates rapidly on a spindle. The cord is prone to breaking. A number of strimmers utilise a cord release mechanism to automatically release additional cord from a spool, when the cutting portion breaks. However, such mechanisms are usually unreliable.

Additionally, strimmers do not collect the grass as it is cut. This necessitates subsequent additional collection of the grass, e.g. using a rake and/or a garden vacuum.

It is desirable to minimise the number of tools required by a homeowner, so as to minimise purchase cost and storage space.

It is an aim of the embodiments to address one or more problems of the prior art, whether described herein or otherwise.

According to a first aspect of the present invention there is provided a cutting apparatus for coupling to an inlet tube of a vacuum machine, the cutting apparatus comprising: a rotary cutting assembly arranged to be driven by airflow from the vacuum machine.

Such an apparatus allows an existing vacuum machine, such as a garden vacuum, to be adapted for use in cutting. As the cutting assembly is driven by airflow

from the vacuum machine, no complex mechanical coupling is required to transfer power from the vacuum machine to drive the rotary cutting assembly. Additionally, as the cutting apparatus is arranged for coupling to the inlet tube of the vacuum machine, grass or other items cut by the rotary cutting assembly can readily be collected utilising the vacuum machine.

Preferably the cutting apparatus comprises a fan positioned for rotation by the airflow, and coupled to the rotary cutting assembly for driving the rotary cutting assembly.

The rotary cutting assembly may be arranged to rotate in a first direction, with the cutting apparatus comprises an array of static vanes for direction of the airflow in a rotational direction opposite to the first direction.

Preferably the rotary cutting assembly comprises at least one cutting blade defining a first cutting edge for cutting of material.

Preferably the cutting blade has a surface orientated for driving the rotary cutting assembly by the airflow.

The cutting apparatus may comprise at least one static cutting element defining a second cutting edge, positioned adjacent the rotational path of said first cutting edge, for cutting material between said first and second cutting edges.

The cutting edge may be curved, and may extend over an arc of at least 45° relative to the rotational axis of the rotary cutting assembly.

Preferably the cutting apparatus is arranged to substantially enclose an end of the inlet tube of the vacuum machine, for directing all of the airflow into the inlet tube through the cutting apparatus.

The cutting apparatus may comprise a guard arranged to substantially enclose the rotary cutting assembly, the guard defining a plurality of slots.

Each slot may have a width of 6mm or less.

The guard may be dome-shaped, with each slot extending within a plane parallel to the rotational axis of the rotary cutting assembly.

Alternatively, the guard may be dome-shaped, with each slot extending within a plane transverse to the rotational axis of the rotary cutting assembly.

Preferably, at least 40% of the surface area of the guard defines a continuous surface.

The cutting apparatus may comprise the vacuum machine for generating an airflow.

The vacuum machine may be garden vacuum.

According to a second aspect of the present invention there is provided a method of manufacturing a cutting apparatus for coupling to an inlet tube of a vacuum machine, the method comprising providing a rotary cutting assembly arranged to be driven by airflow from the vacuum machine; and providing an attachment for coupling the apparatus to the inlet tube.

According to a third aspect of the present invention there is provided a method of operating a cutting apparatus coupled to an inlet tube of a vacuum machine, the cutting apparatus may comprise a rotary cutting assembly arranged to be driven by airflow from the vacuum machine, the. method may comprise holding the cutting assembly adjacent grass or other vegetation for cutting of said grass or other vegetation.

Embodiments 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 perspective view of a vacuum machine and a cutting apparatus in accordance with an embodiment of the present invention;

Figures 2A-2F are respectively a first side view, a first perspective view from the end of the apparatus adjacent the vacuum machine in normal use, a second perspective view from the end of the apparatus distant from the vacuum machine in normal use, a second side view, an end view of the end adjacent the vacuum machine ("top view") in normal use, and an end view of the apparatus distance from the vacuum machine ("bottom end view") in normal use, all of the cutting apparatus illustrated in Figure 1 ;

Figures 3 A-3F are views of the cutting apparatus as illustrated in Figures 2A- 2F, with the outer guard removed;

Figures 4A-4D are respectively a perspective view, a side view, a top view and a bottom view of the rotary cutting assembly of the cutting apparatus illustrated in Figures 1-3F.

Figures 5A-5D are respectively a perspective view, a side view, a top view and a bottom view of the static cutting assembly of the cutting apparatus shown in Figures 1-3F;

Figures 6A-6C are respectively a perspective view, a side view and a top view of the fan of the cutting apparatus illustrated in Figures 1-3F;

Figures 7A-7C are respectively a first side view, a second side view orthogonal to the first side view, and an end view of the shaft of the cutting apparatus illustrated in Figures 1-3F;

Figures 8A-8C are respectively a perspective view, a side view and a top view of the array of static vanes of the cutting apparatus illustrated in Figures 1-3F;

Figures 9A-9E are respectively a perspective view, a first side view, a second side view, a top view and a bottom view of the outer guard of the cutting apparatus illustrated in Figures 1-3F;

Figures 10A- 1OC are respectively a side view, a bottom end view, and a top end view of a cover for application to the outer guard illustrated in Figures 9A-9E; and

Figures 1 IA-I IF are views of the cutting apparatus as illustrated in Figures 2A-2F, with the cover illustrated in Figures 10A- 1OC located in a first position.

Figure 1 shows a perspective view of a garden vacuum 2 (also commonly referred to as a lawn vacuum, lawn blower, or leaf blower or vacuum).

Garden vacuum 2 is arranged to provide an airflow by sucking air in through an inlet tube (shown in Figure 1 as nozzle 6), with the air subsequently being blown out through an outlet orifice (illustrated as side port 8 in Figure 1).

The airflow is provided by a bladed fan driven by either an electric or gas motor. The motor and fan are enclosed in the housing 4.

Garden vacuum 2 is portable, and suitable for carrying by a single person. To facilitate manipulation of the garden vacuum, a handle 5 is provided on the housing 4.

Often, the direction of the fan can be changed, so as to allow the vacuum to operate as a blower i.e. to provide a positive pressure airflow from nozzle 6, rather than the negative pressure airflow typically used to suck material into the nozzle 6.

This particular garden vacuum 2 includes a collection system 10 for collecting material that has been sucked into nozzle 6. Collection system 10 is connected to the

housing 4 by a port coupling 20. Collection system 10 includes a dust cover 30 constructed of a non-porous fabric material, that prevents airflow therethrough. A collection bag 40 is located within dust cover 30. Collection bag 40 is arranged to collect material sucked into nozzle 6, and blown out of side port 20. Collection bag 40 is typically formed of a porous material, to allow the exit of airflow.

The cutting apparatus 100 is shown positioned adjacent the inlet end of the nozzle 6. In use, the cutting apparatus 100 is coupled to the inlet end of the nozzle 6. In the embodiment shown, cutting apparatus 100 comprises a screw thread 102, to allow the cutting apparatus 100 to mate with a corresponding screw thread within the end of nozzle 6. However, any attachment may be used to secure the cutting apparatus 100, so as to mate with the inlet tube of the garden vacuum 2. hi use, the cutting apparatus 100 is mounted on the inlet tube or nozzle of garden vacuum 2, such that the rotary cutting assembly of the cutting apparatus is rotated by airflow into the garden vacuum. The inlet tube or nozzle 6 is cylindrical, and extends along a longitudinal axis. The rotational axis of the cutting assembly is substantially coaxial with the longitudinal axis of the inlet tube, when in use. The rotary cutting assembly cuts material (e.g. grass or other vegetation) as it rotates, with the cut material being sucked into the garden vacuum, and deposited in the collection system 10.

Thus, the cutting apparatus allows a garden vacuum to be readily adapted for use in cutting material e.g. in performing the function of a strimmer. Consequently, a homeowner does not need to purchase a separate strimmer. As the cutting assembly is driven by airflow from the garden vacuum, no complex mechanical coupling is required to transfer power from the vacuum to drive the cutting assembly. Additionally, material cut by the cutting apparatus will be sucked into the garden vacuum, thus avoiding the need to utilise a separate machine for collection of the cut material.

Details of the cutting apparatus 100 will now be described with reference to Figures 2A-9E. In normal use, for cutting grass, the end of the cutting apparatus 100 coupled to the nozzle 6 will generally be held higher than the distal end of the cutting apparatus. This distal end of the apparatus is normally held adjacent the material to be cut, such that portions of the material extend through apertures into the cutting

apparatus 100, for cutting. For convenience only, the end of the cutting apparatus 100 coupled to the nozzle 6 will be described as the "top" end herein, with the distal end being the "bottom" end. This terminology is not to be taken as limiting in any sense. For instance, it will be readily appreciated that the cutting apparatus may be operated by a user holding the garden vacuum such that the cutting apparatus 100 extends above the height of the nozzle 6 e.g. for cutting leaves or other vegetation above head height.

The cutting apparatus 100 comprises a rotary cutting assembly 110 (as shown in detail in Figures 4A-4D). The rotary cutting assembly comprises three cutting blades 112a,b,c mounted upon a common, central shaft 114. The blades 112a,b,c are symmetrically mounted about the shaft 114. The shaft 114 extends along a longitudinal axis, and is rotatably mounted within the cutting apparatus. Each cutting blade defines a curved surface 116a,b,c, curving at an angle relative to the longitudinal axis of the common central shaft 114. Airflow over the curved surfaces of the cutting blades 112a,b,c creates a rotational force, which causes the rotary cutting assembly 110 to rotate (about the longitudinal axis of shaft 114).

Each cutting blade 112a,b,c defines a respective cutting edge 118a,b,c. The cutting edge is located at the end of the cutting blade distant from the central shaft, such that the cutting edge has the greatest possible angular velocity as the rotary cutting assembly 110 rotates. Each cutting edge 118a,b,c extends in an arc from a position substantially parallel to the longitudinal axis of the central shaft (at a position distant from the central shaft) to being substantially perpendicular to the longitudinal axis (at a position adjacent to the central shaft). In other words, the cutting edge extends over an arc of almost 90° relative to the rotational axis of the rotary cutting assembly. This curvature is desirable, as it maximises the range of angles at which the cutting assembly can be presented to material to be cut.

The rotary cutting assembly is mounted within a static cutting assembly 120. Static cutting assembly 120 is shown in more detail in Figures 5A-5D. Static cutting assembly 120 is fixedly mounted within the cutting apparatus 100 i.e. it does not rotate. Static cutting assembly 120 defines a plurality of static cutting elements 122a- 122f. Each element defines a respective cutting edge, which is positioned adjacent the rotational path of the cutting blades 112a,b,c. Each cutting edge of the static

cutting elements also extends along an arc, parallel to the arc of each of the cutting edges of the cutting blades 112a,b,c. Preferably, the separation between the cutting edges of the static cutting elements 112a,b,c,d and the rotational path circumscribed the cutting edges of the cutting blade 112a,b,c is less than 2mm, and even more preferably less than 1mm. As the rotary cutting assembly 110 rotates, material is cut by the shearing action between the cutting edges of the rotating cutting blades and the cutting edges of the static cutting elements. This shearing action can be viewed as a scissor-like action, similar to the cutting action used by a conventional rotary mower.

The static cutting assembly comprises a circular annular top 126, with the static cutting elements 122a- 122f extending arctuately from top 126 to a position 128, coaxial with, but distant from circular top 126. Position 128 defines the lower mounting point 124 of the rotating shaft 140 within the cutting apparatus.

Static cutting elements 122a-122f are not disposed symmetrically about the circumference of the circular top 126. Instead, the majority (five) of the cutting elements are disposed within a predetermined portion (in this example, a semi-circle) of the circular top 126. As will be described below, with reference to the cover illustrated in Figures 10A- 11 F, in preferred embodiments it is desirable that only a portion of the volume swept out by the rotating cutting blades is utilised for cutting, to make the most efficient use of the airflow passing through the cutting apparatus for rotation of the cutting assembly. A single, static cutting element 122f is provided within the other portion of the circular top 126, so as to rigidly support mounting position 128.

In this particular embodiment, the rotation of the rotary cutting assembly by the airflow is achieved by use of both curved cutting blades 112a,b,c, and a fan 130. The fan 130 is illustrated in Figures 6A-6C. The fan 130 is coupled to the rotary cutting assembly 110 via a rotating shaft 140 (shown in detail in Figures 7A-7C). Rotation of the fan 130 thereby facilitates rotation of the rotary cutting assembly 110.

Fan 130 comprises five blades 132a-132e, symmetrically disposed about hub 134. Each blade 132a-132e is curved, so as to cause the fan to rotate by the airflow of the vacuum machine passing over the blade surfaces.

Both central hub 134 of fan 130 and central shaft 114 of the rotary cutting assembly 110 have a central aperture extending therethrough, for fixedly coupling

shaft 140 to fan 130 and assembly 110. Each central aperture is H-shaped, and arranged to couple with the corresponding protrusions of rotating shaft 140. Rotating shaft 140 thus, in the assembled apparatus, extends through both apertures. The first H-shaped portion 142 of shaft 140 thus extends through the aperture in hub 134, with the second H-shaped portion 144 extending through the corresponding aperture within shaft 114. The lower end 146 of the rotating shaft 140 is rotatably mounted at position 124 (e.g. on a bearing). A third portion 148 of the shaft 140, between the first and second portions 142, 144, is rotatably mounted within a collar, to allow the shaft 140 to spin freely about its axis (with corresponding rotation of both fan 130 and rotary cutting assembly 110).

As airflow from the vacuum machine moves through the cutting apparatus 100, the airflow causes cutting assembly 110 to rotate by acting on both the cutting blades 112a-112c and the fan 130. This results in a rotation of the airflow. To improve the efficiency of the interaction of the airflow with the fan 130, an array of static vanes 150 is located along the airflow path between the rotary cutting assembly 110 and the fan 130. The array of static vanes is illustrated in detail in Figures 8A- 8C. The array of static vanes 150 is fixedly mounted within the cutting apparatus 100. hi this particular embodiment, the array of static vanes is fixedly mounted to the circular top 126 of static cutting assembly 120. hi this particular embodiment, the array of static vanes 150 comprises two types of vanes 152, 156. Each vane is mounted upon a common annular mounting 154. Three static vanes 152 are provided, extending from the mounting 154 to the radial centre of the mounting. Vanes 152 support central collar 158. Collar 158, in the assembled apparatus, extends around the third portion 148 of shaft 140, to support the shaft. A larger number of the smaller vanes 154 (in the example shown, 33 of such vanes) are fixedly mounted on the circular inner periphery of the support 154, and extend radially towards the axial centre. Each vane 152, 154 is curved, so as to direct airflow in the opposite rotational direction from the direction that the airflow has been directed by the rotating rotary cutting assembly 110. As both rotary cutting assembly 110 and fan 130 rotate in a common direction, this ensures that the airflow arriving at the fan 130 impacts the blades of the fan 132a-132e at the correct angle so as to achieve the maximum possible rotation of the fan from the airflow.

Preferably, as a safeguard, a guard 160 extends around the rotary cutting assembly 110 and static assembly 120. In this particular embodiment, the remaining parts of the cutting apparatus 100 are mounted within the guard 160. Further, the attachment 102 for coupling the cutting apparatus 100 to the vacuum machine (e.g. garden vacuum 2) is provided on the outer surface of the guard 160. In this particular embodiment, the attachment is a screw thread 102. The guard 160 is substantially dome-shaped e.g. hemispherical. The guard 160 defines three different types of aperture 162, 164, 166. Each aperture is of width sufficient to prevent the ingress of fingers or electrical cable into the cutting apparatus, to prevent accidents. Advantageously, the apertures also prevent ingress of objects of relatively large diameter, that might damage the cutting blades.

Each type of aperture or slot 162, 164, 166 can be utilised for a different cutting purpose.

A first set of apertures 166 is provided at the tip or end of the dome-shaped guard 160. Three slots extend transversely, each slot being within a plane that extends substantially parallel to the longitudinal axis of the dome 160 (i.e. the rotational axis of the rotary cutting assembly 110). hi use, these slots 166 are particularly suitable for accurate trimming of grass or other vegetation in confined spaces. The cutting apparatus and vacuum machine would be held, such that the grass extends into slots 166, for cutting.

A first side of the dome is provided with a plurality of a second type of slot 162, with a second side of the dome provided with a plurality of a third type of slot 164.

The second type of slot 162 extends longitudinally i.e. they extend along the sides of the dome, with each slot extending within a plane parallel to the rotational axis of the rotary cutting assembly. These slots 162 are particularly suitable for use if the cutting apparatus is moved in a direction substantially parallel to the longitudinal axis of the nozzle 6 of the vacuum machine e.g. if the cutting apparatus is used in a similar fashion to a conventional lawn mower, with the cutting motion being performed in straight lines.

By way of contrast, slots 164 are curved, with each slot extending substantially arctuately around the sides of the dome, i.e. each slot substantially

extending substantially within a plane that is transverse to the rotational axis of the rotary cutting assembly/the longitudinal axis of the dome. Such slots 164 are particularly suitable for use if the cutting apparatus is operated by a user sweeping the cutting apparatus in arcs across grass or other similar vegetation.

It will be appreciated that, in typical use, only one of the sets of apertures 162 or 164 will be utilised at any one time. For instance, if the cutting apparatus was utilised with the guard in the orientation shown in Figure 9B, then typically slots 162 would be utilised, whilst if the cutting apparatus was with the guard in the orientation shown in Figure 9C, then the lower slots 164 would be utilised (e.g. to cut grass, on a horizontal surface).

In most applications, it is desirable that the airflow into the vacuum machine is utilised as efficiently as possible, to rotate the rotary cutting assembly at the maximum possible speed. This generally ensures a cleaner cut. Consequently, a cover 170 is preferably provided, as indicated in Figures 10A- 1OC. The cover is arranged to occlude (block) one set of apertures, so as to limit the effective total inlet area. This increases the velocity of the airflow into the vacuum machine, and thus the rotational speed of the cutting assembly 110. Figures 1 IA-I IF show the cover 170 located in a first position, occluding the slots 164. With the cover 170 in such a position, slots 162 or slots 166 could be utilised for cutting material. However, it will be appreciated that equally the cover could be fixed to the guard, so as to occlude slots 162, and to expose slots 164.

The above embodiment is described by way of example only. It will be appreciated that various alternative embodiments will be apparent to the skilled person as falling within the scope of the present invention.

For instance, whilst the present embodiment has been described with reference to a garden vacuum, it will be appreciated that a cutting apparatus as described herein can be coupled to any vacuum machine i.e. any machine arranged to create an airflow. Equally, the cutting apparatus could be formed as an integral part of a vacuum machine.

Although the guard 160 has been shown as being provided with a plurality of different types of slot, it will be appreciated that individual guards could in fact be formed containing only one type of slot over a predetermined portion of the surface

area of the guard. Such a guard could be removably coupled to the cutting apparatus, with different guards being used for different purposes.

The cutting apparatus, or any part thereof, could be formed of any suitable material, including plastic or metal. For instance, the cutting blades 112a,b,c (or at least the cutting edges thereof 118a,b,c) could be formed of any suitable rigid material that maintains an edge e.g. plastic or a metal such as aluminium.

Equally, while the cutting apparatus has been described as cutting using a shearing action between two edges, it will be appreciate that other forms of cutting action may be employed. For instance, the rotary cutting assembly could simply comprise one or more cutting blades, each arranged to cut material with a single cutting edge, rather than performing a shearing action between two edges. Alternatively, one or more cutting cords could be utilised, similar to the cutting cords mounted within a strirnmer. Such a cutting cord (or cords) could be mounted in a similar manner to those employed within the strimrner. Alternatively, one or more pieces of cord could be mounted within the cutting apparatus, with each cord extending between two fixed positions mounted on a rotating assembly.

In the above embodiment, the cutting apparatus is driven by airflow over both a fan and over the cutting blades. In an alternative embodiment, no additional fan is provided, with the cutting apparatus being driven solely by airflow over the blades of the rotating cutting assembly. Alternatively, the rotating cutting assembly could be driven solely by airflow over a fan.