AU714212B2

AU714212B2 - Brush-cutting tool

Info

Publication number: AU714212B2
Application number: AU68019/96A
Authority: AU
Inventors: Peter Thorne
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-10-03
Filing date: 1996-10-03
Publication date: 1999-12-23
Anticipated expiration: 2016-10-03
Also published as: AU6801996A

Description

Regulation 3.2 -1-

AUSTRALIA

Patents Act 1990 C4F'IMP1[,E: rE 03P1E XF I C!2!P IC)1jS OSZLn lz 3P_7kM1D Rz7p F:

APPLICANT:

NUMBER:

FILING DATE: PETER THORNE PN5 760 3/10/95 Invention Title: BRUSH-CUTTING

TOOL

The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 "BRUSH-CUTTING TOOL" FIELD OF THE INVENTION This invention relates to a brush-cutting tool.

BACKGROUND ART A brush-cutting tool including a circular hub and a nylon cord is well known. As the hub spins on the shaft of a brush-cutter, the nylon cord assumes a radial orientation due to centrifugal force and acts as the cutting member. A major drawback with nylon cord brush-cufftting tools is that the cord lacks robustness and must be regularly replaced. Furthermore, nylon cord brush-cutters struggle to cut through tougher weeds and other vegetation.

:15 Also known is a brush-cutting tool including a circular hub and a fixed radial blade member. Whilst such arrangements can generally deal with tougher weeds and are more robust than the nylon cord cutters, they suffer a number of disadvantages including the undesirable tendency to transmit impact shock to the brush-cutter in the event that the blade member strikes a rock or the like.

Also known are grass mowers having a hub with blade members mounted thereto.

SSUMMARY OF THE INVENTION This invention in one aspect resides in a brush-cutting tool including:a hub adapted to be mounted on the shaft of a brush-cutter for rotation therewith; a link member pivotably mounted with respect to the hub; and a blade member pivotably mounted with respect to the link member wherein the link member is pivotably mounted with respect to the hub for relative rotation about a first axis and the blade member is pivotably mounted with respect to the link member for relative rotation about a second axis, the first and second axes being spaced and 3 parallel and wherein the hub, link member and blade member lie in a common plane, the plane being perpendicular to the first and second axes.

Preferably, the hub, link member and blade member jointly define a leading edge adapted to cut vegetation, and wherein the leading edge is shaped such that cut vegetation may slide outwardly along the leading edge.

BRIEF DESCRIPTION OF THE FIGURES In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein:- S• FIG 1 is a plan view of a brush-cutting tool according to the invention; FIG 2 is a perspective view of the brush-cutting tool of FIG 1;o1 5 FIG 3 is a perspective view of a second brush-cutting tool according to the invention; FIG 4 is a plan view of the brush-cutting tool of FIG 3; and FIG 5 is an elevation view of the brush-cutting tool of FIG 3.

:20 BEST MODE

S

With reference to the FIGS in which the same numerals have been used to identify the same features in both embodiments, brush-cutting tool 2 includes hub 4 and blade members 6 pivotably mounted to the hub by link members 8.

It will be noted that link members 8 include a pair of spaced arms which straddle hub 4 and blade member 6. The components are riveted together for pivotable movement.

Hub 4 includes a central aperture 10 which, in use, receives the spigot or shaft of the brush-cutter. The aperture is not threaded and therefore is compatible with all brush-cutters.

The hub 4 of the first embodiment is generally diamond shaped whilst the hub 4 of the second embodiment is generally round in shape with diametrically opposed lobes.

Due to the shape of hub 4, link members 8 and blade members 6 may pivot through a substantial angle relative to hub 4 before abutting or impacting hub 4. This is important in avoiding the transmission of impact shocks to the gearbox of the brushcutter pursuant to the blade member striking a rock or the like.

It will also be noted that the brush-cutting tool as a whole is substantially planar and that the components of the brush cutting tool pivot relative to each other about axes which are perpendicular to the plane. As a result, when blade member 6 rebounds from striking a rock or the like, it strikes hub 4 rather than striking the shaft of the brushcutter.

The hub, by virtue of its shape, assists in cutting and greatly reduces tangling in long grass. When tangling does occur, it is relatively easy to clear. If brush-cutting tool 2 was rotated in a clock-wise direction, peripheral edge (of the hub) 14, peripheral edge (of the link member) 16 and peripheral edge (of the blade member) 18 together define the leading or cutting edge of the tool.

The leading or cutting edge is substantially smooth or devoid of obstructions or e protrusions which would prevent vegetation which is cut by the tool from sliding outwardly along the leading edge due to centrifugal force. This feature is important in a shedding vegetation and preventing tangling of the tool.

The tool is preferably made of steel although it could made of other material S such as plastics. In one embodiment the hub and link members are steel however the blade member is plastics and is replaceable.

Due to the symmetry of the tool it can be rotated in either direction. This means the tool can be reversed when one leading edge becomes worn. The trailing edge then becomes the new leading edge.

It has been found that the blades do not require sharpening. Rather the leading edge of the blade which is initially square in section wears to a curved shape which, if anything, is sharper.

It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

9*

Claims

2. A brush-cutting tool as claimed in claim 1, wherein the hub includes two diametrically opposed lobes, each lobe including mounting means for pivotably mounting a link member.
3. A brush-cutting tool as claimed in claim 1, wherein the link member includes a pair of spaced arms which straddle the hub and the blade member. .0 *0 20 4. A brush-cutting tool as claimed in claim 1, wherein the hub, link member and V blade member jointly define a leading edge adapted to cut vegetation, and wherein the leading edge is shaped such that cut vegetation may slide outwardly along the leading 0 edge.
5. A brush-cutting tool as claimed in claim 4, wherein there is a smooth transition between the portion of the leading edge defined by the hub and the portion of the leading edge defined by the link member.
6. A brush-cutting tool as claimed in claim 4 or 5, wherein there is a smooth transition between the portion of the leading edge defined by the link member and the portion of the leading edge defined by the blade member.
7. A brush-cuffing tool substantially as herein described with reference to the FIGS. 4. .4 9 4 4 04s4 S S 4. S S. *0 4O S S. SS S 55 S SS .4 5 4,0. 0 S. ~d 050 *5 0 S. @0 S