AU684123B2 - Cutter assembly for lawn mowers - Google Patents

Description

Our Ref: 531768 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT o e o s o Applicant(s): Address for Service: Invention Title: Rover Mowers Limited 155 Fison Avenue EAGLE FARM QLD 4007

AUSTRALIA

DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Cutter assembly for lawn mowers The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 -1- CUTTER ASSEMBLY FOR LAWN MOWERS This invention relates generally to lawn mowers and more particularly, to an improved cutter assembly for use in lawn mowers of the rotary type and to parts associated with the cutter assembly. Whilst reference is made to mowers for lawn this is not to be taken as a limitation on the scope of the invention as it will be apparent that the apparatus could be used for cutting other grasses and types of crops and the like.

Cutter assemblies for rotary lawn mowers which are currently known generally comprise a rotatable cutter mounting element to which is mounted a series of cutter blades. The rotatable mounting element is disposed in a chamber within a lawn mower housing which includes a discharge outlet through which lawn cuttings are directed to a catcher or away from the chamber.

One of the problems associated with rotary lawn mowers of this type is that when the grass is wet it is relatively difficult for the mower to be able to efficiently discharge 15 the wet lawn clippings from the chamber through to the outlet. The clippings tend to remain in the chamber and block the outlet. Fan blades have been used in the past to encourage air flow from the cutting region in the chamber towards the discharge outlet.

One form of such fan blades currently in use are generally rectangular in shape and are mounted in the region of the chamber above blade mounting element. Fan blades of this 20 type have not proven to be particularly efficient and generally lead to an increase in noise when the mower is in operation.

It is an object of the present invention to provide an improved cutter assembly *.and/or fan blade device for use therewith which alleviates one or more of the aforementioned problems.

According to one aspect of the present invention there is provided a fan blade device suitable for use with a cutter assembly for lawn mower, the cutter assembly including a rotatable cutter mounting member having a plurality of cutters secured thereto, the cutter mounting member when in use being rotatable about an axis of rotation, the fan blade device when in an operative position being operatively connected to the cutter p:\wpdocs1dys\spccie\rovetdys '4 blade device when in an operative position being operatively connected to the cutter mounting member and including a generally upright section which in the operative position of the fan blade device extends from the cutter mounting member generally in a direction ger.eraly parallel to the axis of rotation and a trailing section which in the operative position extends rearwardly from the upright section with respect to the direction of rotation of the cutter mounting member.

According to another aspect of the present invention there is provided a cutter assembly for a lawn mower including a housing having a chamber therein and a discharge outlet for discharging material from the chamber, the cutter blade assembly including a mounting member which, in use, is mounted for rotation within the chamber, at least one cutter blade operatively connected to the mounting member and at least one fan blade device as described above operatively connected to the mounting member, the fan blade device being configured so that when the mounting member rotates it causes clippings to be transferred towards the discharge outlet, there further being provided an aperture in the mounting member behind at least one or more of the fan blade with respect to the direction of rotation thereof It is believed that the fan blade device when in use, creates an air flow sufficient to S 20 e or aid in the removal of grass clippings or other material and/or by striking the clippings.

e• The cutter mounting element may be in the form of a bar or a rotatable disc-like e member. Preferably, the cutter mounting element is in the form of a domed disc-like element with the cutters which project from the disc-like element at its peripheral edge when in its normal operative position and the or each fan blade device is disposed on the upper side.

Preferably, two fan blade devices are provided which are preferably diametrically oppositely disposed with respect to the central axis of rotation and towards or adjacent the peripheral edge of the cutter disc. Because of this arrangement it is believed they inhibit the entrapment of material such as string or the like to wrap around the drive shaft of the 7 mower to which the cuter assembly is operatively connected.

S T p:Xwpdocdys~specie\531768,spe dl I ~i~BU yB~IUI ~ar*ul loslr^ -I -3- Preferably, an aperture is provided in the disc behind each fan blade with respect to the direction of rotating the disc. It is believed the apertures substantially eliminate an)y vacuum created and consequential reduction of power. The apertures also tend to reduce noise during operation of the mower.

As mentioned earlier each fan blade device may comprise a generally upright section and a trailing section extending rearwardly with respect to the direction of rotation and are disposed towards the outer free end of the upright section. The upright section is believed to create suction and the rearwardly extending section is believed to create lift.

Preferably, the trailing section is generally triangular in shape and extends beyond the peripheral edge of the cutter disc or mounting arm. In the assembled position there is only a small clearance between the outer edge of the blade and the inner surface of the chamber within the mower body. The fan blades may be formed in any suitable fashion and from any suitable material such as metal.

Preferred embodiments of the invention will hereinafter be described with reference to the accompanying drawings in which Figure 1 is a schematic perspective view of a cutter assembly; S 20 Figure 2 is a perspective view of a fan blade device according to the present invention; Figure 3 is a first side elevation of the fan blade device shown in Figure 2; Figure 4 is a second side elevation of the fan blade device shown in Figures 2 and 3; Figure 5 is an end elevation of the fan blade device shown in Figures 2 to 4; Figure 6 is a plan view of the cutter assembly shown in Figure 1; Figure 7 is a first side elevation of the cutter assembly shown in Figures 1 and 6; and Figure 8 is a second side elevation of the cutter assembly shown in Figures 1, 6 and 7 shown at right angles to the side elevation view shown in Figure 7.

Referring to the drawings the assembly 1 generally comprises a circular disc-like body 2 having a series of mountings 3 for cutter blades (not shown), the disc-like body p.%pdoc dys\spciexovcr\dys _I i"4~C-II~PLF( IIIC~XIIP~ -4being rotatable about a central axis A-A. The disc includes s domed section 5 and a mounting section 6 by which it is mounted for rotation within a chamber in the mower housing as is normal practice. Tile mounting section to may be secured to a drive shaft of a drive means. The drive means such as an electric or internal combustion motor is arranged to rotate the disc in the conventional fashion.

On the upper surface of the disc there is provided two fan blade elements 7, each fan blade element comprising a mounting flange portion 8, by which the fan blade elements are mounted to the disc using bolts 12, an upright portion 9 and a triangular shaped trailing portion 10. As best seen in Figures 3 and 4 the upright portion 9 of the fan blade element has inclined edges 9a and 9b extending from the trailing portion towards mounting flange portion 8. As best seen in Figures 1 and 8 when the fan blades 7 are mounted to the disc 2 at least part of the rearwardly extending portion 10 of the blades 7 extends beyond the peripheral edge of disc 2. Two fan blades 7 are provided these being disposed diametrically from one another. Although only two fan blades are shown, it will be appreciated that more than two or even a rxingle fan blade could be S: provided.

Apertures 11 are formed in the disc 2 there being an aperture behind each of the fan blades 7 with respect to the direction of rotation of the disc 2. The positioning of the apertures tends to lend to more efficient and quieter operation.

•When in operation the disc rotates and the cutter blades cut the lawn in conventional fashion. The law clippings tend to pass between the peripheral edge of the disc and the inner surface of the chamber. The fan blades tend to draw the clippings into the region above the disc and from there they are discharged through the discharge outlet.

It has been found that by using the fan blades as shown, wet clippings tend not to clog the chamber and as such the mower can be readily operated in wet conditions.

Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or am!;t of the invention.

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Claims (9)

1. A fan blade device suitable for use with a cutter assembly for lawn mower, the cutter assembly including a rotatable cutter mounting member having a plurality of cutters secured thereto, the cutter mounting member when in use being rotatable about an axis of rotation, the fan blade device when in an operative position being operatively connected to the cutter mounting member and including a generally upright section which in the operative position of the fan blade device extends from the cutter mounting member generally in a direction generally parallel to the axis of rotation and a trailing section which in the operative position extends rearwardly from the upright section with respect to the direction of rotation of the cutter mounting member.

2. A fan blade device according t0 claim 1, wherein said trailing section extends beyond a peripheral edge of the cutter mounting member when the fan blade device is in the operative position.

3. A fan blade device according to claim I or claim 2, wherein said trailing section is generally triangular in shape with one edge portion of the triangular shaped section being operatively connected to said upright section.

4. A fan blade device according to any preceding claim wherein said trailing section 1: is operatively connected to said upright section along an edge portion of said upright section remote from the cutter mounting member when in the operative position.

5. A fan blade device according to any preceding claim including a mounting flange extending laterally from said upright section which in the operative position is secured to the cutter mounting member.

6. A cutter assembly for a lawn mower including a housing having a chamber therein and a discharge outlet, the cutter blade assembly including a mounting member which, in use, is mounted for rotation within the chamber, at least one cutter blade operatively I; ^t connected to the mounting member and at least one fan blade device according to any I, 5%pdocuXsdspesi j 53 Il~p preceding claim operatively connected to the mounting member, the fan blade device being configured so that when the mounting member rotates it causes clippings to be transferred towards the discharge outlet, there further being provided an aperture in the mounting member behind each fan blade with respect to the direction of rotation thereof.

7. A cutter assembly according to claim 6, wherein said mounting member includes a disc-like body which in the normal operative position has an upper surface the or each said fan blade device being operatively connected to said upper surface.

S. A fan blade device substantially as hereinbefore described with reference to the accompanying drawings.

9. A cutter assembly substantially as hereinbefore described with reference to the accompanying drawings. o 5 a *a. DATED this 26th day of August, 1997 ROVER MOWERS LIMITED By Their Patent Attorneys DAVIES COLLISON CAVE V'p -a 1 Arr~ o p\ylplotsl'dysi'Spci5176(8 spelt -c r I~ ABSTRACT A fan blade device for use with a cutter assembly for lawn mower, the cutter assembly including a rotatable cutter mounting member having a plurality of cutters secured thereto. The fan blade device when in an operative position is operatively connected to the cutter mounting member and includes a generally upright section which in the operative position of the fan blade device extends from the cutter mounting member generally in the direction of the axis of rotation of the cutter mounting member. The fan blade device has a trailing section which in the operative position extends rearwardly from the upright section with respect to the direction of rotation of the cutter mounting member. o 0 ee e ee e o* p\wpdocsdys speci\rovcr\dys