GB2283651A - Rotary mower - Google Patents

Abstract

A rotary mower has a sledge guard 11 and a rotary blade 14 wherein the leading cutting edge is downwardly bevelled. Added safety can be achieved by leaning the cutting edge back form radial, (51) Fig. 7 to give a spreading effect. The blade is far less dangerous by not being designed to force cut material in an upward direction. <IMAGE>

Description

PRECAUTIONARY ROTARY MOWING This invention relates to precautionary safety measures and the cutting principle of rotary mowers.

Rotary mowers have to propel their cutting blades at a great speed in order to cut a soft pliable herbage such as grass ect.

Because it does not have a shear blade like the cylinder mower or like the old agricultural mowers, the shape of the blade has varied but the principle of having the sharp edge at the bottom side of the blade has remained the same, this makes the blade very dangerous, and does not cut the grass to its full potential considering the action of the blade is of a whiplash principle.

The most important part of a mower is the blade, the rest of the mower is there to help the blade to perform its function, but when a mower is advertised we read, deluxe grass catcher, self propelled, safety engine brake, height adjustment and so on, but never, high performance cutting blade with inherant safety feature this invention is aimed in that direction, there are numerous safety features fitted to rotary mowers, all are designed to protect the operator from this dangerous blade, but none of these have been to make the blade itself safer, and most are designed to prevent access from the side, but not from below.

There is a need in the market for a safer blade, safety measures on the market at present do not cover that need, blade breaks?.

No one can anticipate as accident, therefore one can only apply the brake after the event, plastic blades?. These are putting the rotary mower into the toy section, they should and can be a precision cutting machine, the trend for vacuum collection of the cut material has influenced the design of the blades, ie. blades are being raised at the rear to propel the cut material upwards into the vacuum system, the airofoil designed blade, this is designed to create a force on the topside of the blade to propel the cut material into the vacuum system, both of these have made the blade more dangerous, so the design is at the expence of safety, if it is necessary to propel the cut foliage in an upward direction, it would be preferable to attatch a plastic (or other soft material), propeller type blade to the centre drive housing to follow the cutting blade, this could be designed specifically to scoop up the cut foliage and propel it upwards into the vacuum system, leaving the cutting blade just to cut the grass.

FOOTNOTE: The word "Slope" will be used throughout this text when referring to the leading front side of the blade which has been ground.

To give the blade a sharp edge.

According to the present invention, precautionary rotary mowing, there is provided a safer cutting blade and a sledge guard, wheerin safety of the operator and the whiplash principle have been taken into account, the mower is provided with a blade which has the sharp edge at the topside of the blade this relating to the safety aspect, affords the operator a greater chance of not receiving severe lasserations as is known to happen when an operator accidentaly pulls the mower on top of his or her foot, this is because of the slope, this is a very important factor, it is the slope that is the distinguishing factor beteen what is already known, and this invention, it is designed to do the exact opposite to what is in production now, which is it draws the blade downwards when it strikes a solid object, this invention is designed to push the blade upwards, away from the stricken object, thus reducing the amount of injury, this blade is also designed so that the cutting edge which is at the topside of the blade does not receive the amount of wear that is inflicted on a blade with the sharp dege at the bottom side, also no modification of the machine is necessary to incorporate the blade or sledge guard, so they can be fitted to machines in use as well as new machines.

Taking the whiplash principle, this can best be explained by pointing out that vegetation is anchord in the soil, thus when it is struck by a blade which is sharp at the bottom side, the sharp edge hits the vegetation, the top part of the vegetation is forced backward and is cushioned by the slope which is on the topside, thus preventing a clean cut, with this invention, when the sharp edge strikes the vegetation, the top part of the vegetation is forced backward allowing the sharp edge to make a clean cut because the slope is on the bottom side.

The sledge guard is designed to give added safety from below, it protects a persons foot from coming into contact with the blade from front and sides, it also prevents the bladefrom scalping when mowing the edges of the lawn being of V shape it spreads and flips the grass as the blade cuts, and running so close to the soil it spreads any wormcasts before the rear roller pans them, as can be seen the rear part of the cutting radius is not covered, this is to allow the blade free access to cut any uncut foliage this guard consists of 4 bars, the two outside shorter bars protect the outside, side radius while the two inside longer bars protect the front and rear radius, the angle of the vee can be variable also the bar spacing, it may be necessary to add more bars to the formation on the larger machines, this guard gives free access for the removal of the blade so the guard can be of a fixed nature or can be made detatchable, the bars should be made of a substantial material taking into account the wear factor and the need for rigidity, but should not be so thick as to prevent the mower cutting at its lowest setting.

This guard is of enormous benefit to the larger machines who have to contend with extreme mowing conditions, undulating and potholed surfaces also where there are surface tree roots, it allows you to mow right over them without causing any damage, the present blades with the sharp edge at the bottomside of the blade do not conform to this guard as they tend to use the bars as a shear blade, this could lead to problems.

This includes the airofoil shaped blade, the tilted blade, which can be adjustable or be in a fixed position enables the operator to tilt the blade upwards when working in very stoney conditions this not only makes the blade safer but protects the cutting edge from damage, also it allows the blade to pass over the stones and not catapult them in all directions.

With a blade with a sharp edge at the topside of the blade, causing the blade to revolve quicker, or, having multiple blades increases its safety by making it more impenetrable, causing a blade to be thicker increases its safety because it has a longer slope, causing the blade to revolve quicker reduces the need for a long sharpened edge, reducing the angle of the slope below 45degs. causes it to be less safe, increasing the angle above 45 degs. makes it safer, the slope can be multy faceted, convex or concave, the sharpened edge can lean forward from the radial line, or can lean backward from the radial line, having added features to the blade, ie.being raised at the rear to propel the cut foliage in a desired direction makes it more dangerous, a blade with an airofoil shape is more dangerous because of the height of the slope, the sharp edge of the blade can be any distance from the top surface of the blade to the bottom surface of the blade, but the closer to the top surface the safer it becomes, this invention can be applied to any machine with rotating blades, whether electrically powered or combustion driven machines.

A specific embodyment of the invention will now be described by way of example with reference to the accompanying drawing in which:- Fig. 1. shows in perspective a side elevation, partly broken away of a mower cutting grass, illustrating blade and guard.

Fig. 2. shows a view of the underside of a mower illustrating the position of blade and guard.

Fig. 3. shows an end view of a blade now in production in comparison to the new blade.

Fig. 4. shows an end view of a new blade, illustrating the blade in tilted position.

Fig. 5. shows an end view of a blade now in production with raised rear portion.

Fig. 6. shows an end view of a blade now in production with an airofoil shape.

Fig. 7. shows 2 blades, illustrating top, how the cutting section of the blade can lean forward of the radial line, and bottom how the cutting section can lean back from the radial line.

Refering to the drawing Fig.l. this shows a mower cutting grass, illustrating how the blade 14.which has the sharp cutting edge at the topside of the blade is able to cut the grass clean because the slope 10 is below the cutting level, 12. illustrates the cut foliage, 11 and llA shows the guard illustrating its mowing position in relation to ground level and blade position, 16 shows the front wheel of the mower, 17 shows the rear roller.

Fig.2. is the view of the underside of a mower, illustrating how the bars are in a vee formation spreading out to the rear, indicated by the front wheels 16 and the rear roller 17 it will be seen by this view that the blade 14 is rotating in an anticlockwise direction the aforesaid benefits can clearly be seen from this view, Fig. 3, demonstrates the difference between the old design and the new design, the old design at the bottom shows the sharp tutting edge 21, at the bottom side, and the slope 20 above the cutting line, both exerting a downward thrust, the new blade top, shows the cutting edge 15 at the topside of the blade and the slope 10 below the cutting line, both exerting an upward thrust. Fig. 4 shows a new blade 14 illustrating the same blade in tilted position 28, Fig. 5 shows an old blade which is raised at the rear to propel cut foliage in an upward direction to conform to the vacuum system Fig. 6. shows an airofoil shaped blade 40, 14 illustrates an old blade for comparison it can be seen that the sharp edge 21 is at the bottom side the same as the old blade, 41 indicates the slope, 42 indicates the height of the slope, Fig. 7 this shows two blades the top one 50 indicates the blade leaning forward from the radial line, this gives the blade a gathering effect the bottom one 51 indicates the blade leaning back from the radial line giving a spreading effect.

Claims (18)

CLAIMS.

1. Precautionary rotary mowing comprising a blade, a tilted blade, and a sledge guard.

2. Precautionary rotary mowing as claimed in claimed in Claim 1.wherein the blade whatever shape or size will have the sharp edge at the topside of the blade.

3. Precautionary rotary mowing as claimed in Claim 1 or Claim 2 wherein the length of the sharpened portion will be determined by the R.P.M.

4. Precautionary rotary mowing as claimed in Claim l.wherein the slope can be of any shape.

5. Precautionary rotary mowing as claimed in Claim 4 wherein the angle of the slope can be varied.

6. Precautionary rotary mowing as claimed in Claim 4 or in Claim 5 wherein the slope will be designed to create a lifting force beneath the blade.

7. Precautionary rotary mowing as claimed in any proceeding claim wherein the tilt can be variable by adjustment or fixed in manufacture.

8. Precautionary rotary mowing as claimed in Claim 7 wherein the variable tilt blade will be in two equal halves and will be provided with means of attachment to the centre drive houseing.

9. Precautionary rotary mowing as claimed in Claim 8 wherein the centre drive houseing will have means provided for secureing and adjusting the tilt.

10. Precautionary rotary mowing as claimed in Claim 1, wherein the sledge guard will be provided with bars that run in a vee formation from the front of the mower spreading out to the rear of the mower.

11. Precautionary rotary mowing as claimed in Claim 10 wherein the number of bars in the guard can be varied.

12. Precautionary rotary mowing as claimed in Claim 10 wherein the size and the shape of the bars can be varied.

CLAIMS.

13. Precautionary rotary mowing as claimed in Claim 10 wherein the composition of the bars will be of suficient strength for rigidity and wear.

14. Precautionary rotary mowing as claimed in Claim 10 wherein the guard can be of a detatchable design or can be as a fixed component.

15. Precautionary rotary mowing as claimed in Claim 10, wherein the mower will be provided with means for attatchment of the sledge guard.

16. Precautionary rotary mowing as claimed in Claim 10 wherein the angle of the vee can be variable.

17. Precautionary rotary mowing as claimed in any previous claim wherein the guard will be attatched to the underside of the mower allowing the mower to cut at its lowest setting.

18. Precautionary rotary mowing substantially as described herein with reference to Figures 1 - 7 of the accompanying drawing.