AU667907B2 - Cutting disk - Google Patents

Description

OPI DATE 13/12/93 APPLN. ID 40522/93111111 IIIIIIII AOJP DATE 24/02/94 PCT NUMBER PCT/AU93/00227 11111 11111111111111 AU9340522 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 93/22897 A01D 34/73 Al (43) International Publication Date: 25 November 1993 (25.11.93) (21) International Application Number: PCT/AU93/00227 (81) Designated States: AT, AU, BB, BG, BR, CA, CH, CZ, DE, DK, ES, FI, GB, HU, JP, KP, KR, KZ, LK, LU, (22) International Filing Dat.: 14 May 1993 (14.05.93) MG, MN, MW, NL, NO, NZ, PL, PT, RO, RU, SD, SE, SK, UA, US, VN, European patent (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), Priority data: OAPI patent (BF, BJ, CF, CG, CI, CM, GA. GN, ML, PL2431 15 May 1992 (15.05.92) AU MR, NE, SN, TD, TG).

(71) Applicant (for all designated States except US): HARTLEY Published BLADES PTY, LTD. [AU'AU]; Section 615 Hundreth, With international search report.

Muddla Wirra, S.A. 5400 With amended claims.

(72) Inventor; and Inventor/Applicant (for US only): EGGLETON, Allan, Benjamin [AU/AU]; 7 Cameron Tce., Mallala, S.A. 5502

(AU).

(74) Agent: WYK, Paul, 118 King William Street, Adelaide, S.A. 5000 (AU).

(54)Title: CUTTING DISK Ii 1 1 (57) Abstract A cutting disk for cutting vegetation from a ground surface. The cutting disk has a dish shaped body with at least one cutting edge defined within a slot in the dish. The slot and cutting edge urge the cut vegetation to be carried onto the cutting disk. Preferably wings are provided at a periphery of the disk so as to urge cut vegetation towards the middle of the disk. Radially extending walls and a central boss on the disk, act on the trajectory of the cut vegetation carried on the disk to redirect the vegetation radially outwardly, and thereby dispose of the cut vegetation.

S".cr/Au 9 3 0 0 2 2 7 RECEIVED o 4 MAR 199L 1 CUTTING DISK This invention relates to a cutting disk for use with a rotary cutter. Such a cutting disk is suitable for use with any cutting apparatus such as forexample a rotary lawn mower, and the invention encompasses an apparatus with a cutting disk.

The cutting disk according to this invention might be used for cutting a number of different types of vegetation and included in such vegetation are lawns, assorted grasses and any other vegetation that can be cut by a rotary blade.

For simplicity however the specification will, in parts, refer to grass.

1 0 A problem with the cutting of grass with conventional grass cutting apparatuses such as lawnmowers is an inefficiency in the removal of the cut grass.

Generally lawnmowers are provided with cutting blades in the form of sharpened blades equally spaced apart and extending away from the 1 5 periphery of a dish-shaped supporting body which is adapted for rotation, so that on rotation the blades slash through the vegetation that is to be cut. The blades are shaped with a view to imparting lift to the vegetation that is cut but only every provide a limited amount of lift because the blade have a very small surface area that acts to lift.

2 0 Furthermore the blade that cuts a particular tuft of grass does not act to lift that particular tuft of grass. The tendency of grass that is struck by a blade is to fold up when partly severed and to a certain extent an upper portion of the grass is given a downward component to its trajectory. Grass when cut also tends to adhere, to some extent, to the blade thereby inhibiting the lifting effect. Any lifting pressure that is exerted by reason of the shape of the blade therefore has a number of opposing factors to overcome.

Grass that is lifted off the ground is forced towards a catcher or catchment area by reason of the momentum imparted to the grass by the rotation of the blade.

The amount of time for which the blades contact the grass is only very small 3 0 and thus not all of the grass has sufficient momentum imparted on it to carry the cut grass to the catcher or catchment area.

i It is an object of the present invention to provide a cutting disk which will AMENDED SHEET TPfIA/A'j ,4 PC'IAU 9 0 2 2 7 RECEIVED o MAR 19 2 obviate or minimize any one of the foregoing disadvantages in a simple yet effective manner or at least provide the public with a useful choice, In one form the invention could be said to reside in a cutting disk for cutting vegetation from a ground surface said cutting disk having a dish shaped body 1 5 said body having formed therein at least one cutting edge within a slot in the i said dish the slot being an open slot extending inwardly from a periphery of ii the dish, said slots and cutting edge so positioned that cut vegetation is j carried onto the dish shaped body wherein said body includes impeller means adjacent to and downstream of the cutting edge, relative to the 1 0 direction of rotation of the cutting disk, said impeller. means positioned to i impart an inward trajectory to the cut vegetation so as to urge the cut vegetation toward the middle of the disk.

Thus in use vegetation that is cut does not fall onto the ground surface, but is lifted up onto the dish and is maintained above the ground level.

i 15 In a preferred form the body is solid and thus has no perforations. This form of ii the invention enhances the lifting action of the dish shaped body.

*1 For ease of manufacture and to maximize the cutting action of the disk the slot is an open slot extending from a periphery of the dish.

In a second preferred form the cutting disk has a central boss and a wall on an upper surface of the body the wall extending substantially radially in the body, said wall being downstream of said cutting edge and said impeller means, said wall and boss both being positioned to create positive air pressure such that the cut vegetation is caused to be urged radially out of the disk. The cut vegetation once it has been lifted on top of the disk is thereby thrown back out.

Preferably a lift means is also positioned adjacent to and downstream of the cutting edge, and acts to impart an upward component trajectory to the cut vegetation. The upward trajectory imparts a lift onto the cut vegetation so that by the time that the cut vegetation is thrown off of the cutting disk it is more 3 0 likely to have a higher position than the incoming vegetation.

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YI ii'- C~nun~ a, ,c~ PCIA 9 3 0 0 2 2 7 RECEIVED O 4 MAR

I

3 The disk is preferably in close proximity to a housing of a cutting apparatus, and the wall acts as a means of diverting the trajectory of the cut grass back to the centre of the disk and the trajectory from there is diverted outwardly to facilitate the flinging of the cut vegetation into the catcher or catchment area.

In one form the wall has a sloping side extending away from the direction of rotation. The sloping side imparts a greater lift on the cut grass. The sloping ;i side has the effect of further enhancing the collection of the grass from the site of cutting.

/i For a better understanding the invention will now be described with reference I 1 0 to two embodiments, wherein ji FIG. 1 is a plan view from below of one embodiment of the invention, i FIG. 2 is a plan view from above of the embodiment shown in FIG. 1, FIG. 3 is a side elevation of the embodiment shown in FIG. 1, and FIG. 5 is a part cut away view of the blade mounted within a lawnmower.

1 5 The cutting disk according to the illustrated embodiment of the invention has a dish shaped body 1 with eight cutting edges 2 extending inwardly from a i periphery of the body and within a slot 3. The body of the cutting disk is formed from a metal such as mild steel. The direction of rotation of the disk is shown by arrow 4. Eight wings 5 are provided at the periphery of the body I 20 and extend upwardly. These are formed by deforming the body of the disk by turning up the mild steel from the side of the slot that is upstream from an adjacent cutting edge.

Four walls 6 made from a strip of curved metal are welded onto the upper surface of the cutting disk, as seen in FIG 2.

A central boss 7 is located at the centre of the cutting disk and is adapted for attachment to a drive means and in this example are adapted for attachment to the drive of a lawnmower.

The body of the cutting disk can be seen in the illustrations to be continuous <T OAMENDED SHEET

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_1 j PCi/U 9 3 0 0 2 27 RECEIVED 4 1AR 1994 4 except for the slots, and has no perforation other than the slots.

The cutting edges are formed from wear resistant strips of metal and thus have a wear resistant slurface.

When positioned within a cutting apparatus such as the lawnmower 8 shown in FIG. 5, the cutting disk is held in relatively close proximity to a housing 9 at thie periphery of the cutting disk 10. This positioning enhances the capacity of the blade to urge grass into the middle of the cutting blade, At the rear of the illustrated lawnmower, can be seen a duct 11 communicating with a catcher, through which duct the cut grass can be thrown.

1 0 For the first embodiment in use the cutting disk is rotated in the direction shown by arrow 4, grass is severed by the cutting edge 2, the cut portion of the grass falls on top of the disk and is urged to an interior portion of the disk by wings 5 which act to pump the grass inwardly under air pressure. The wings also have a lifting effect on the cut grass. Walls 6 divert the path of the cut 1 5 grass toward the central boss. The central boss is somewhat raised and acts to divert the grass back away from the interior of the cutting disk. The general lifting of the firstly by the wings and secondly by the sloping wall, act on the path of the cut grass so that on being ejected it is generally raised above the incoming grass. To some extent the pathway of the grass through the blade could be described as cyclonic.

This embodiment is found to be far more effective in the removal of grass from a cutting site. t provides a far greater lifting effect firstly by reason of the provision of a solid disk, and secondly by reason of the lifting effect caused by the wings 5. Furthermore the cut grass is in contact with the cutting disk for a far greater time than with conventional lawnmower blades and thus the momentum imparted on the cut grass is greater leading to a more effective deposition of cut grass into a catcher.

It is found that if a greater lifting effect is required the walls 6 can be provided with a sloping slide extending in the direction of rotation so as to impart a 3 0 further lift on the cut grass.

A' The whole cutting disk may be made of a number of suitable materials for example the body may be moulded, from a suitably hard plastic.

AMENDED SHEET r- L PCT/AU 9 0 0 2. 7 RECEIVED o4 MAR 199L; The simple provision of a cutting disk with slots 3 a cutting edge 2 but no means to lift and force grass into the interior of the cutting disk also has a beneficial effect in :erms of lifting the grass from the cutting surface. The efficiency of the redirection of grass once on top of the blade is somewhat diminished however, this embodiment still overcomes the difficulties caused by conventional rotary grass cutting blades.

It is further to be understood that the number of cutting edges can be varied, and it may be desired only to have one cutting edge..

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Claims (14)

1. A cutting disk for cutting vegetation from a ground surface said cutting disk having a dish shaped body said body having formed therein at least one cutting edge within a slot in the said dish the slot being an open slot extending inwardly from a periphery of the dish, said slots and cutting edge so positioned that cut vegetation is carried onto the dish shaped body wherein said body includes impeller means spaced rearward of the cutting edge, with respect to the direction of rotation of the cutting disk, said impeller means positioned to impart an inward trajectory to the cut vegetation so as to urge the 1 0 cut vegetation toward the middle of the disk.

2. A cutting disk as in claim 1 wherein the body is continuous except for said slots and thus otherwise has no perforations.

3. A cutting disk as in any one of the preceding claims wherein one side of said slot has a wear resistant surface to form the cutting edge. 1 5

4. A cutting disk as in claim 1 wherein the impeller includes at least one wing extending upwardly from the dish and extending rearwardly away from the slot, said wing being angled inwardly to the Interior of the dish In the direction of rotation of the cutting disk.

A cutting disk as in claim 4 wherein said wing is so positioned to impart an upward component of trajectory to the cut vegetation.

6. A cutting disk as in either claim 4 or 5 wherein said wing extends inwardly from the periphery, and is spaced rearward of a said cutting edge,

7. A cutting disk as in claim 1 having on an upper surface a central boss and at least two radially extending walls dividing the upper surface of the cutting disk into two compartments each bounded by the central boss, and radially by a forward face of one of said walls and a rearward face of the other of said walls, wherein each of said compartments includes a respective one of said cutting edges within one of said slots, and a wing extending upwardly Rfrom the dish and extending rearwardly away from each of the slots, said wing jR4 0 being angled inwardly to the interior of the dish in the direction of rotation of AME D SUET PEA/AU Pr/AU 9 3 0 02 2 7 i' CEIVED 22 MAR 1994 7 the cutting disk, said wing, said rearward face, said boss, and said forward face positioned so as to act together as an impeller and thereby acting to impart a cyclonic effect on vegetation cut by said disk.

8. A cutting disk as in claim 7 wherein the walls each have a sloping side extending upwardly away from the direction of rotation.

9. A cutting disk as in any one of claims 4 to 8 wherein the body is formed of sheet metal and wherein the wings are provided by an upward deformation of the body of the cutting edge.

A cutting apparatus including a cutting disk as-defined in any one of the preceding claims, said cutting disk being supported for rotation In a cutting position within a housing, and said apparatus including a drive means coupled with the disk for rotation of the disk.

11. A cutting apparatus as in claim 10 wherein the cutting disk is so supported to be in close proximity with an inside surface of said housing and 1 5 so as to bias the cut vegetation to be retained on said cutting disk.

12. A cutting disk for cutting vegetation from a ground surface said cutting disk having a dish shaped body, a central boss, and at least two radially extending walls dividing the upper surface of the cutting disk into two compartments each compartment bounded by the central boss, and radially by a forward face of a respective one of said walls and a rearward face of a respective other of said walls, each compartment including a respective wing extending upwardly at a periphery of the dish and being angled inwardly to the interior of the dish in the direction of rotation of the cutting disk, a respective cutting edge formed within an open slot extending inwardly from a periphery of the dish and being forward and spaced apart from said wing, said cutting edge formed to deliver cut vegetation onto the compartment and said wings, walls and central boss being positioned collectively to draw cut grass into an interior of the compartment before throwing cut vegetation radially 3 0 away from the compartment. T

13. A cutting disk in claim 12 wherein said wings, walls and central boss are positioned collectively to impart a counter rotational cyclonic effect on cut IPEA/AU AME D SHEET t w i,, I SPTA9 02 PCr/AU 9 3 0 02 2 7 RECEIVED 2 2 MAR 1994 vegetation delivered into the compartment, to thereby throw cut vegetation radially away from the compartment.

14. A cutting disk as in claim 12 wherein the body is continuous except for said slots and thus otherwise has no perforations. A cutting disk as in claim 12 wherein one side of said slot has a wear resistant surface to form the cutting edge. 1 0 16. A cutting disk as in claim 12 wherein the walls and wings each have a sloping side extending upwardly away from the direction of rotation. i i I i i i Ij t ii f i i i i ii i f 1 j i i i i i i j r i B *1 AMENDED SHEET IPEA/AU