AU658675B2

AU658675B2 - Cutting blade assembly

Info

Publication number: AU658675B2
Application number: AU27002/92A
Authority: AU
Inventors: George Michael Stickney
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-10-15
Filing date: 1992-10-14
Publication date: 1995-04-27
Anticipated expiration: 2012-10-14
Also published as: AU2700292A

Description

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AUSTRALIA

Patents Act 658675 COMPLETE SPECIFICATION

(ORIGINAL)

Application Number: Lodged: Class Int. Class Complete Specification Lodged: Accepted: Published: Priority Related Art:

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Applicant(s): GEORGE MICHAEL STICKNEY 3 Leith Court Sunbury, Victoria, 3429

AUSTRALIA

Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: "CUTTING BLADE ASSEMBLY" Our Ref: 307680 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 1 7 c CUTTING BLADE ASSEMBLY This invention relates to cutting blades, and is particularly but not exclusively concerned with a cutting blade assembly for cutting grass. A cutting blade assembly according to the invention is especially suited for use on a rotary lawnmower and it will be convenient to describe the invention with particular reference to that exemplary application. It is to be appreciated however, that the invention can be used in other applications.

Conventional rotary lawnmowers incorporate a rotating cutter disc supporting a pair of diametrically opposed cutting blades. These blades move in a common cutting plane as the cutter disc is rotated to cut the grass as the lawnmower is 1 moved across a lawn. The lawnmower can cut and spread the grass cuttings on the lawn. Alternatively the lawnmower can include a catcher arrangement for catching the grass cuttings.

There are advantages in spreading the grass cuttings on the lawn. Firstly, the grass cuttings act as a mulch for •92" the lawn. Furthermore, it is not necessary to periodically interrupt the mowing of the lawn to unload the catcher arrangement. The problem of disposal of the grass cuttings is also avoided. However, problems can arise if excessive amounts of grass cuttings are spread on the lawn.

2. 5- It is therefore an object of the present invention to provide a cutting blade assembly which at least subtantially overcomes the above drawback.

i--Wah this in mindL, the Prq!cnt inventisn provides a cutting bladk assembly suitable for use with a rotary lawnmower, said ssembly comprising a first blade having a first cutting edge a a second blade adjacent the first blade and having a second cut jng edge, wherein the second cutting edge is positioned on a dif irent plane to the first cutting edge.

The term "cutting directio refers to the direction in which the blades move during use whe utting.

The present invention also p vides a rotary lawnmower having cutting blade assemblies as de ribed above.

39f .The first blade mav be in the form of Pan nnaal-g _6_ I t4 J 2 K:rl With this in mind, the present invention provides a cutting blade assembly suitable for use with a rotary lawnmower, said assembly comprising a first blade having a first cutting edge and a second blade adjacent the first blade and having a second cutting edge, wherein the second cutting edge is positioned on a different plane to the first cutting edge, and wherein at least one of said blades includes a deflector vane located on an edge of said one of said blades opposite to that of said cutting edge, said deflector vane being adapted to deflect cut material to a designated area.

The term "cutting direction" refers to the direction in which the blades move during use when cutting.

The present invention also provides a rotary lawnmower having cutting blade assemblies as described above.

The first blade may be in the form of an elongate r r rrr r r o r ro

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2a strip member and may have a cutting end and a mounting end at the opposing ends thereof. The cutting end may include primary cutting edge along at least a portion of ond side thereof. A portion of the opposite side of the cutting end may be bent at an angle from the general plane of the first -FOcm *tI- eblade to aodeflecting vane thereon.

The second blade may also be in the form of an elongate strip member having opposing cutting and mounting ends. A second cutting edge may be provided along at least a portion of the side of the cutting end and a deflecting vane may also be provided.

The second blade may be positioned at an angle S. relative to the first blade so that the secondary cutting edge of the second blade is positioned either behind, level with, or in front of the primary cutting edge relative to the cutting directio:, of the blades.

The blade assembly may also include provision for additional blades, the number being limited only by the size of the blade assembly and the cutting/mulching effect required. The additional blades, in a similar manner to the first and second blades, may include a cutting end and a mounting end at opposing ends thereof and may include a cutting edge along at least a portion of one side thereof and a deflecting vane. Additional blades may be positioned at an angle to the first and second blades, or may be positioned between these blades at varying angles to suit the prevailing conditions.

The mounting end of the first blade may include means to facilitate mounting on the cutter disc of a rotary lawnmower. The mounting means may for example include an aperture extending through the mounting end. The aperture may be substantially circular and may be provided with diametrically opposed notches., The first blade may be secured to the cutter disc by a fastener bolt passing through the aperture, the bolt having lugs for engaging the notches for preventing or minimising pivotal movement of the first blade when assembled on the disc.

The mounting end of the second blade may include 3 .means for facilitating the support of the second blade 3/ adjacent the first blade and may include an aperture passing through the mounting end. The fastener bolt for mounting the first blade to the cutter disc may also pass through the second blade aperture to hnld the first and second blades together in adjacent relation on the cutter disc.

Additional blades may be mounted in a similar manner to the first and second blades, with an aperture passing through the mounting end. It may however, be too bulky to mount more than two blades on a fastener bolt and therefore, it may be necessary to fix additional blades to an additional fastener bolt(s).

Engagement means may also be provided between the o first, second and additional blades to hold the blades in the required positions. For example, aligned holes may be provided through both blades for accommodating a rivet or other fastener therethrough. Alternatively, or in addition, at least one lug or similar member may extend from a face of one of the blades for co-operating with a hole in the adjacent blade. It is also envisaged that one of the blades be secured 0. directly to the adjacent blade in the required position with the said adjacent blade including the mounting means for o° mounting to the cutter disc.

At least the respective cutting ends of the blades may be spaced apart when mounted together. The first and S second cutting edges may therefore be supported in different cutting planes, as may any additional blades. At least one of the blades may be bent to provide a bent leg portion so that the cutting ends are separated when the blades are mounted together. For example, the second blade may have a bent leg portion to hold the second blade cutting end below the first blade cutting end. The first blade can be at least substantially flat. It is also envisaged that the first blade have a bent leg portion for separating the respective cutting ends. The second blade can therefore be at least substantially flat. It is envisaged that where three blades are provided, at least two of the blades will have bent leg portions and so on as more blades are added. This arrangement ensures that there is no blade exposed below the level of the 39 "skirt" of the lawnmower when the cutting blade assembly is 4 mounted on the cutter disc.

Alternatively, or in addition, a spacer may be provided between blades to separate the respective cu'tting ends. It is also envisaged that the blades be arranged alternatively about the top and bottom sides of the cutter disk. For example, in the most simple arrangement of first and second blades, the first blade may be supportable on the top of the cutter disc with the second blade being supportable on the bottom of the disc adjacent the first blade.

The cutting blades on a conventional rotary lawnmower can be replaced with the cutting blade assembly of the present o' invention. A pair of these cutting blade assemblies may for example be mounted on the cutter disc in place of the cutting blades. In use, considering first the arrangement comprising ~first and second blades, the first cutting edges of the first blades move in a first cutting plane to initially cut the grass with the second cutting edges of the second blades following behind the first blades in a second cutting plane to cut the grass a second time. It has been found that it is optional as to whether the uppermost blade or the lowermost blade leads in the cutting direction. The deflecting vanes of the blades act as a suction fan when the cutting blade assemblie-3 are rotated to draw at least a substantial portion of the cut grass into a catcher arrangement on the lawnmower.

The suction force will increase with an increased number of deflecting vanes. Where the first blade is provided with a deflecting vane, the cuttings caught in the catcher are primarily cut by the first blades and the cuttings produced by the second blades are primarily spread onto the lawn as mulch material. As much of the grass is cut and caught, only a small amount is distributed as mulch material. This avoids the problem of excessive cuttings being distributed on the lawn. Also the volume of cuttings caught at any set period is reduced so that the catcher does not need to be unloaded as frequently. Furthermore, it has been found that the use of the cutting blade assembly of the present invention when cutting long grass reduces the load on the lawnmower.

Where two blades are each provided with a deflecting 39 vane, the percentage of grass caught in the catcher increases t over that caught by an assembly comprising a single blade having a deflecting vane.

It is also envisaged, that, in one embodiment, the deflector vane may be provided by one of the blades themselves, ie. in a two blade arrangement, the first blade would be located to cut the grass and the second blade would solely perform the function as the deflecting vane. Where more than two blades are used, any one, or any number of the blades may be assembled solely as deflecting vanes.

Where more than two blades are used, the above advantages are enhanced ie the mulching effect is increased, while the grass not mulched is more efficiently thrown into the grass catcher. The arrangement of the blades may be varied to determine the percentage of grass caught compared to grass mulched. The mulch is generally produced by the lower blade in a two blade arrangement, or by a combination of the lower blades where more than two blades are used. The blade or blades located between the uppermost and lowermost blades, assist in both the catching of the grass and also in mulching ~what is not caught.

To ensure that the cuttings produced by the blade(s) are spread as mulch material, a deflecting shield may also be included in the blade assembly. The deflecting shield may be in the form of a curved plate secured to the bottom of the uppermost blade. The shield may extend from the uppermost blade and around the rear edge of the next or successive blades. The shield is spaced away from the rear edges of the blades so that grass cut by the cutting edge of the next or successive blades would also be deflected towards the ground.

Where more than two blades are used, the shield may be located on a lower blade, but not the lowermost blade.

The deflecting shield serves to deflect a percentage of grass dippings downwardly from the blade arrangement for mulching purposes, thereby reducing the amount of grass passing through to the catcher. This enhances fertilisation of the mown surface and reduces the number of times the catcher need be emptied. This aspect is environmentally sound as less grass clippings are disposed of at garbage dumps.

39 It is also envisaged that all blades may be flat in 6 which case, separate suction fan means may be required to enable a portion of the cuttings to be caught. Alternatively, all blades may act as mulching blades to produce finely Cut grass cuttings as mulching material, where it is acceptable to spread all the grass cuttings on the lawn.

In order to assist in arriving at an understanding of the present invention, example cutting blade assemblies are illustrated in the attached drawings. As the drawings only illustrate example assemblies, their particularity is not to be understood as superseding the generality of the preceding description.

In the drawings: Figure 1 is an exploded perspective view showing a first example embodiment of the cutting blade assembly of the present invention; Figure 2 is a bottom view of the cutting blade assembly of Figure 1; Figure 3 is a partial cross-sectional side view of the cutting blade assembly of Figure 1; and Figure 4 is a perspective view of a second example embodiment of the cutting blade assembly of the present invention.

Figure 5 is a partial cross-sectional side view of a third example embodiment of the cutting blade assembly of the .2 present invention.

The same reference numerals are used for corresponding features in each example embodiment. Referring initially to Figures 1 to 3, the cutting blade assembly includes a first blade 1 and a second blade 2. The first blade 1 has a cutting end 4 and an opposing mounting end 3.

The second blade 2 similarly has a cutting end 5 and mounting end 6. The first blade cutting end 4 includes a first cutting edge 7 on one side thereof. The opposing side of the cutting end 4 is bent at an angle to the rest of the first blade 1 to provide a deflecting vane 8.

The second blade cutting end 5 includes a second cutting edge 11 on one side thereof. When the two blades are mounted adjacent to each other, the second cutting edge 11 in 39 this embodiment is located behind the first cutting edge 7 7 relative to the cutting direction of the blades as shown in Figure 2.

Bent leg sections 16, 17 are provided on the first and/or second blades 1, 2 to ensure that the respective cutting ends 4, 5 are spaced apart so that the first and second cutting edges 7, 11 can move in different cutting planes.

The first blade mounting end 3 has a substantially circular aperture 9 with diametrically opposed notches 10. A fastener bolt may be passed through the aperture 9 to secure the cutting blade assembly to the cutter disc of a lawnmower, the bolt including lugs for engaging the notches .An aperture 12 is also provided in the second blade mounting end 6 for accommodating the shaft of the fastener ~bolt so that the first and second blades 1, 2 can be mounted together on the cutter disc.

Further holes 13 are provided through the second blade 2 to assist in locating that blade 2 relative to the first blade 1.

Rivets 14 may for example be passed through corresponding holes in the first blade 1 and the holes 13 in the second blade 2 as shown in Figure 2. Alternatively, lugs 15 may protrude from the first blade 1 and engage the cooperating holes 13 in the second blade 2.

ae In another example embodiment of the cutting blade assembly as shown in Figure 4, the second blade 2 is separated from the first blade 1 by a spacer or bush 18 located between the mounting ends 3, 6 thereof. The spacer provides a clearance between the blades 1, 2 and the second blade 2 does not require the bent leg portion and can be a flat blade as shown in Figure 4. In this later embodiment, it is also envisaged that the first blade 1 be mounted on top of the cutter disc with the second blade 2 being mounted below the cutter disc and adjacent the first blade 1, the cutter disc acting as the spacer therebetween.

In another example embodiment of the cutting blade assembly as shown in Figure 5, an additional third blade 19 is shown. Blade 19 includes bent leg section 20 and cutting edge 39 21. Third blade 19 is attached to first and second blades 1, 8 i I I _L~1 2 by common rivet 14.

Alternatively, third blade 19 may be spaced from first and second blades i, 2, whereby it may be attactked to the cutting disk by a further rivet or by other suitable attachment means. In a similar manner, further additional blades may be added, either to the same rivet 14, or to further attachment means located adjacent or near to the first attachment means. It should be understood that, while Figure shows each blade having a bent portion, one of the blades may be entirely flat.

Finally, it is to be understood that various modifications and/or alterations may be made to the cutting S .i blade assembly without departing from the ambit of the present invention as described herein.

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Claims

2. A cutting blade assembly according to claim 1 further comprising a third blade located adjacent said second blade, said third blade having a third cutting edge and being positioned on a different plane to the second cutting edge.
3. A cutting blade assembly according to claim 2, wherein said blades are arranged such that said third cutting edge is spaced in a Qirection from said second cutting edge and said second blade is spaced in the same direction from said first cutting edge.
4. A cutting blade assembly according to any one of claims 1 to 3, wherein at least one of said cutting blades 25 includes a bent leg to enable the cutting edges of adjacent blades to be spaced apart. A cutting blade assembly according to any one of claims 1 to 4, wherein said cutting blades are spaced apart by spacers. 30 6. A cutting blade assembly according to any one of claims 1 to 5, wherein said first blade is the uppermost blade.
7. A cutting blade assembly according to any one of claims 1 to 6, wherein said first blade is the lowermost blade.
8. A cutting blade assembly according to claim 7 wherein said deflector vane is formed by said second blade.
9. A cutting blade assembly according to claim 7, wherein said deflector vane comprises a lip disposed at an 4' 4 401 10 angle to the plane of the cutting blade. A cutting blade assembly according to claim 9, wherein said angle is between 00 and 900.
11. A cutting blade assembly according to any one of claims 1 to 10, wherein at least one of said blades includes a deflector shield located on said one of said blades, said deflector shield being adapted to deflect cut material in a designated direction.
12. A cutting blade assembly according to any one of claims 1 to 11, wherein said cutting blade assembly is attached by attachment means to a lawnmower cutting disc.
13. A cutting blade assembly according to claim 12, wherein each cutting blade has a mounting region spaced from its cutting edge for mounting to said cutting disc.
14. A cutting blade assembly according to claim 12 or claim 13, wherein at least one blade 's located on one side of said cutting disc and another blade is located on the other side of said cutting disc. A cutting blade assembly according to claim 13 or 2( claim 14, wherein said attachment means comprises passing a bolt through an aperture located in said mounting region, said aperture having at least one notch located at its periphery and said bolt having a corresponding lug to engage said notch, in order to prevent or minimise pivotal 25 movement of said cutting blade relativ- to said cutting disk.
16. A cutting blade assembly according to claim wherein said attachment means further comprises engagement means between adjacent blades to locate said blades 30 relative to one another.
17. A cutting blade assembly according to claim 16, wherein said engagement means comprises lugs extending from one cutting blade and adapted to engage an opening in an adjacent cutting bldde.
18. A cutting blade assembly according to claim 16, wherein said engagement means comprises permanently fixing adjacent blades together.
19. A lawnmower including the cutting blade assembly of any one of claims 1 to
40- 11- 4 x rr r r r r I I r ri Ir 1~111~ /'6i~F r i i I i (I Da"-dp -7jA' OurRef: IRN231151 abmln27O2.doc A lawnmower according to claim 20, when dependent upon any one of claims 1 to 18, wherein said deflector vane deflects cut material into an area suitable for the connection of a catcher arrangement. 21. A lawnmower according to claim 19 or claim 20, when dependent on any one of claims 11 to 18 wherein said deflector shield deflects cut material toward the ground upon which the lawnmower is cutting. 22. A cutting blade assembly substantially as herein described with reference to any one of the embodiments as illustrated in the accompanying drawings. DATED: 16 February 1995 PHILLIPS ORMONDE FITZPATRICK Attorneys for: GEORGE MICHAEL STICKNEY kAAA.46 k t^ oini oi i I I r Irr ar Ir ir r r I~rll~ 12