AU7179400A - Grass mower - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention title: Grass Mower The following statement is a full description of this invention, including the best method of performning it known to us: dxbm M0110815856v1 999995 22.11.2000 FIELD OF THE INVENTION This invention relates to a grass mower as well as a hub for it and for a brush cutter.

BACKGROUND OF THE INVENTION Grass mowers of the petrol driven type are generally bulky and heavy and it is an object of the present invention to provide a mower which is inexpensive, light in mass and therefore easy to operate, and which can be provided with a wide cut. Other objects and advantages of the invention will be become apparent as this specification proceeds.

The conventional brush cutter has a hub to the periphery of which strip of nylon or the like are attached. The hub is driven by a motor and the strips are spin at speed to cut grass and other vegetable matter.

The resistance offered by the hub to the air uses a substantial proportion of the power of the motor which could otherwise be used to drive a cutter of greater effective diameter i.e. the strips may be longer. In one form of hub there are curved reinforcing members which are believed to assist in the removal of the cut grass by virtue of the induced current of air, but which do present a large surface area to the air and thereby seem to require power of proportion to the benefit gained.

Another problem of the conventional hub is the difficulty of replacing worn or broken strips.

Some hubs require the strips to be bent into difficult curves and which therefore require considerable finger strength. The configuration of the attachment means of the strips often results in premature wear or damage to the strips.

It is another object of the present invention to provide a hub which presents a minimum resistance to air and which also provides simple, inexpensive and efficient formations for attaching the strips.

THE INVENTION According to the invention a grass mower includes a cowling adapted to receive a brush cutter in grass mowing relationship.

In a preferred form of the invention the shaft of the brush cutter extends through the top of the cowling and is secured thereto. The securing means may include a collar and retaining screw so that the cutter may be adjusted as to height above the ground. The collar may also include means for correct alignment of the shaft of the cutter for example it may have a ridge which corresponds with a slot in the shaft of the cutter, or vice versa.

As the rotor of a brush cutter is normally at an angle to the shaft, the angle of attachment of the cutter will have to be calculated according.

In a refinement of the invention an air cushion may be provided and this can be operated by the motor of the brush cutter.

It will be appreciated that the mower will be extremely light and very easy to use.

The brush cutter may easily be removed from the cowling should it be required for special use, such as edging.

Another advantage of the present invention is that it is not necessary to sweep up grass cuttings, as the brush cutter reduces the mown grass into a highly particulate form which S mulches easily.

S" .i According to a further aspect of the invention a hub for a brush cutter includes a flat plate with peripheral radial eyelets with contiguous peripheral holes having diameters smaller than the width of the enlarged ends of the cutting strips and slightly greater than the diameters of the strips, the eyelets being adapted to receive the strips from the holes for the strips to extend outwardly in cutting configuration.

In one form of the invention, the hub has a raised central zone to provide a gap between the top surface thereof and the motor.

In an example of the invention the eyelets comprise short tubes which are welded or otherwise affixed in detents formed around the periphery of the hub, the holes being located at a suitable distance from the eyelets to ensure a gentle curve of the strips between the holes and the eyelets.

An embodiment of the invention is described below with reference to the accompanying drawings, in which: Figure 1 is a side view of an arrangement according to the invention; Figure 2 is a bottom view of the arrangement; Figure 3 is a front view of the means of attachment of the brush cutter; Figure 4 is a plan view of a hub according to the invention; And Figure 5 is a sectional side view thereof.

In the drawings, a grass cutter includes a cowling 10 which has handles 12 and wheels 14.

ooooo A brush cutter 16 is attached to the cowling at an angle to suit the angle of the rotor 20. The attachment comprises a ferrule 22 which includes a sleeve 24 with a tightening screw 26.

:The ferrule receives the shaft 30 of the brush cutter, which can be adjusted as to the height of cut required.

The rotor 20 is provided with plastic cutting straps 40 which effect a very efficient cutting operation and which reduce the grass cuttings to a fine particular material which mulches easily.

In the Figures 4 and 5 the hub has a central raised zone 50 to provide a gap between the top of the hub and the bottom of the motor (not shown).

-4- A pair of eyelets 52 are located in detents 54 on the periphery of the hub and are welded or otherwise secured in position. These eyes take the form of the short tubes.

Contiguous with the eyelets are holes 56 which receive the cutting strips 58. These strips have enlarged rear portions 60 which are wide enough to be retained on the underside of the holes and whose diameter is smaller than the holes so that they can pass therethrough.

Thereafter, they are curved as at 62 and thence pass through the eyelets.

The replacement of the strips is very easily achieved and the replacement equally so.

*o oooo

Claims (10)

1. A grass mower including a cowling adapted to receive a brush cutter in grass mowing relationship.

2. The grass mower according to claim 1 in which the shaft of the brush cutter extends through the top of the cowling and is secured thereto.

3. The grass mower according to either of the above claims in which the securing means includes a collar and retaining screw so that the cutter may be adjusted as to height above the ground.

4. The grass mower according to claim 3 in which the collar also includes means for correct alignment of the shaft of the cutter. The grass mower according to claim 4 in which the collar has a ridge which corresponds with a slot in the shaft of the cutter, or vice versa.

6. The grass cutter according to any of the above claims in which an air cushion is provided which is operated by the motor of the brush cutter.

7. A hub for a brush cutter inclues a flat plate with peripheral radial eyelets with contiguous peripheral holes having diameters smaller than the width of the enlarged ends of the cutting strips and slightly greater than the diameters of the strips, the eyelets being adapted to receive the strips from the holes for the strips to extend outwardly in cutting configuration.

8. A hub according claim 7 which has a raised central zone to provide a gap between the top surface thereof and the motor.

9. i A hub according to claim 7 or 8 in which the eyelets comprise short tubes which are welded or otherwise affixed in detents formed around the periphery of the hub, the holes being located at a suitable distance from the eyelets to ensure a gentle curve of the strips between the holes and the eyelets. A grass mower including a brush cutter with a hub according to any of claims 7 to 9. o.. 0 0 .0.0 00.0 0* 0 00*00 0 V.00, 00. 0. 0.

11. A hub and strips arranged substantially as described with reference to Figures 4 and -7- A grass cutter substantially as described with reference to Figures 1 to 3.

13. A grass cutter according to claim 12 having a hub and strips according to claim 11. DIRK JACOBUS VAN DER WALT 23 November 2000 a a. a a a. a a. -8-