GB2455714A

GB2455714A - Vegetation Maintenance Apparatus

Info

Publication number: GB2455714A
Application number: GB0724547A
Authority: GB
Inventors: Christopher Martin Lole
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-12-18
Filing date: 2007-12-18
Publication date: 2009-06-24
Also published as: GB0724547D0

Abstract

Vegetation maintenance apparatus comprising a rotor 32, a number of operating elements 36, 38, 40 pivotally connected to the rotor 32 so that the pivot axis increases its distance from the rotational axis of the rotor with increasing distance from the vegetation bearing surface. The operating elements 36, 38, 40 comprise a mounting portion 54 which is pivotally connected to the rotor 32 and an operating portion 76 which is inclined towards the mounting portion 54 in such a way that the operating portion 76 lies parallel to the vegetation bearing surface. The rotor 32 may be provided with attachment members 44 to which the operating elements 36, 38, 40 are attached. The attachment members 44 comprise a first portion 46 secured to the rotor 32 and a second portion 48 to which the operating element36, 38, 40 is pivotally attached. The attachment member 44 may be constructed from a sheet material, which provides the inclination of the pivot axis of the operating member 76. The inclination of the attachment member 44 may cause an upward air flow when rotating.

Description

Title: Vegetation Maintenance Apparatus DescnDtion of Invention This invention relates to vegetation maintenance apparatus, of the kind which includes a rotor which in use is caused to rotate about an axis extending generally perpendicular to a surface bearing the vegetation which is to be maintained, the rotor carrying a number of operating elements which are pivotably connected to the rotor, for operating on the vegetation.

The invention has been devised, and hereafter will be described, in relation to a mowing machine for grass or other vegetation for example stubble, wherein a mowing head carries one or a number of rotors each of which has a rotational axis which, in being generally perpendicular to the ground on which the grass or other vegetation grows, extends more or less vertically when the machine is being used on flat level ground. Each rotor carries a number of operating (cutting) elements spaced circumferentially thereabout. The cutting elements, being pivotably connected to the rotor, extend radially outwardly therefrom under centrifugal force in use, to cut the vegetation. However, if an obstruction such as a stone is encountered by a cutting element, it is able to pivot backwardly with respect to the direction in which it is rotating with the rotor, so that it is less likely to be damaged from its encounter with the obstruction.

Hitherto, it has been usual to connect the cutting elements to the rotor about respective pivot axes which are substantially parallel to the axis of rotation of the rotor. A typical cutting element has been of cranked form, having a mounting portion at which the pivotable connection is made, an operating portion having a cutting edge, and an intermediate portion extending at an angle to both the mounting portion and operating portion, so that the operating portion can be closer to the ground than is the mounting portion and the mounting portion of the cutting element and the rotor can be spaced from the ground. Each cutting element may include a surface portion which is inclined so as to produce an upward flow of air in the vicinity of the cutting elements: this is advantageous because it lifts the blades of grass towards the cutting element, improving the efficiency of cutting.

Such known arrangements have disadvantages. One such disadvantage is that, although a cutting element can pivot backwardly when it meets an obstruction, because the axis about which it is pivotally connected to the rotor is parallel to the rotational axis thereof, the operating portion of the cutting element is still rotating at the same distance from the ground as previously, albeit at a smaller distance from the rotational axis of the rotor. Therefore it is still vulnerable to damage from a large obstruction. Also, when the cutting element has pivoted backwardly it is no longer able to partake in creating the upwards air flow in the vicinity of the cutting elements. The cutting elements might continue to rotate in contact with or very close to the ground surface, causing damage to the growth of grass.

It is broadly the object of the present invention to overcome or reduce these disadvantages of previously known arrangements of vegetation maintenance apparatus.

According to one aspect of the present invention, we provide vegetation maintenance apparatus including a rotor which in use is driven to rotate about an axis extending generally perpendicular to a surface having vegetation which is to be maintained, and a number of operating elements pivotably connected to the rotor for operating on the vegetation, wherein each of the operating elements is connected to the rotor for angular movement about a pivot axis which is inclined outwardly relative to the rotational axis.

By uinclined outwardly"1 we mean that the pivot axis increases its distance from the rotational axis with increasing distance from the vegetation-bearing surface.

Preferably, the pivot axis is also inclined forwardly relative to the rotational axis.

By "inclined forwardly", we mean that the pivot axis increases its distance ahead, having regard to the normal direction of rotation of the rotor in use, of the plane containing the rotational axis of the rotor and the pivotal connection of the operating element to the rotor, with increasing distance from the vegetation-bearing surface.

Apparatus in accordance with the invention has the advantage that, when an operating element is caused to be pivoted rearwardly if it encounters an obstruction, its end remote from the pivotal connection is caused to be lifted away from the vegetation-bearing surface, i.e. raised away from the ground surface in the case of a mowing machine. Therefore, the operating element, and indeed other components of the apparatus, are less vulnerable to damage. Whilst this effect would be achieved to some extent if the pivotal axis of the operating element were just to be inclined outwardly relative to the rotational axis of the rotor, a greater such effect is also obtained if the pivotal axis is also inclined forwardly as is preferred in the invention.

Each operating element may comprise a mounting portion with which the pivotal connection to the rotor is established, and an operating portion, the mounting and operating portions being inclined to one another. Such inclination, in the case of a cutting element for a mowing machine, is preferably such that the operating portion of the operating element, which has a cutting edge, lies generally parallel to the vegetation-bearing surface.

Preferably the rotor is provided with a number of attachment members each of which provides for the connection of the operating elements. Each attachment member preferably comprises a first portion secured to the rotor and a second portion for the pivotal connection of the respective operating element. Each attachment member may be of sheet material, with the first portion lying in a plane generally perpendicular to the axis of rotation of the rotor and the second portion inclined thereto to provide the inclination of the pivot axis of the operating member relative to the rotational axis of the rotor.

Preferably the second portion of the attachment member is inclined so as to cause an upward airflow in the vicinity thereof when rotating in the normal in-use direction.

In an apparatus having attachment members in accordance with the invention as above described, the configuration of the attachment members has the result that even when the operating elements are pivoted rearwardly if an obstruction is encountered, the upward airflow in the vicinity thereof is maintained by the attachment members as long as the rotor continues to rotate.

The apparatus may be a mowing machine and the operating elements include a cutting formation(s) on the operating portions thereof.

According to another aspect of the invention we provide an operating element for a vegetation maintenance apparatus in accordance with the first aspect of the invention, the operating element comprising a mounting portion and an operating portion, such portions being inclined to one another.

The operating portion may be provided with cutting formations at opposite edges which extend generally radially outward from the rotor when the operating element extends outwardly therefrom in normal use.

Whilst in the following description a mowing machine having only a single rotor is described, it will be appreciated that some mowing machines incorporate a number of rotors, e.g. three, four or five. It is common that not all those rotors rotate in the same direction as one another. If a cutting element used on one of the rotors has its cutting edge which is the leading edge on that rotor damaged, if the cutting element has both its leading and trailing edges formed as cutting edges, it may be used on a rotor rotating in the opposite direction.

Thereby, the service life of a cutting element can, in effect, be doubled with a consequent saving in the need for provision of replacement cutting elements.

The invention will now be described by way of example with reference to the accompanying drawings of which: Figure 1 is a perspective view, from one side, the rear, and above, of vegetation maintenance apparatus in the form of a mowing machine embodying the invention.

Figure 2 is a perspective view from the same side, the front and below, of the mowing machine of figure 1.

Figure 3 is a rear view of the mowing machine.

Figure 4 is perspective view, from one side and above, of a rotor assembly and cutting elements of the mowing machine.

Figure 5 is an exploded perspective view of the rotor assembly.

Referring firstly to figures 1, 2 and 3 of the drawings, the illustrated mowing machine comprises a body indicated generally at 101 with a deck 12, upright side waIls 14, an upright front wall 16, and an inclined rear wall 18. The side walls 14 extend downwardly to approach very closely a ground surface on which the mowing machine is being used, while the front and rear walls 16, 18 extend less far. At the front end of the deck 12, there is provided a structure indicated generally at 20 for attaching the mowing machine to a tractor by a three-point attachment arrangement. Three-point attachment devices for tractors, and structure such as that indicated at 20, are well-known and therefore will not be described herein in any greater detail. At the rear of the deck 12, a supporting bracket 22 is provided for carrying, by means of a supporting arm 24, a wheel 26. The wheel 26 is carried by a fork and a shaft 28 which is supported relative to the arm 24 by a bearing, so that the wheel can pivot in the manner of a castor. The height of the supporting arm 24 is adjustable relative to the bracket 22, thereby adjusting the vertical setting of the wheel 26 and hence the cutting height of the mowing machine.

A cutting assembly, indicated generally at 30 in figures 2 and 3 of the drawings, and shown in greater detail in figures 4 and 5, is supported centrally beneath the deck 12. This includes a rotor 32 which is carried by a shaft (not shown) extending downwardly from a right-angle drive gearbox 34. An input shaft of the gearbox 34 is connected to a telescopic drive shaft 36 having universal joints at its opposite ends, of which a first universal joint 38 is adapted for connection to the power take-off (PTO) shaft of a tractor to which the mowing machine is coupled, while at the other end of the drive shaft a further universal joint disposed within a guard 40 connects to the input shaft of the gearbox.

In figure 4, the rotor 32 and components carried thereby are rotatable about a rotational axis 34 which extends vertically or very nearly so, i.e. generally perpendicular to the ground surface on which the mowing machine is being used. The rotor carries three cutting blade assemblies, equally circumferentially spaced about the rotor so that it is rotationally balanced. The cutting blade assemblies are indicated generally at 36, 38, 40.

The cutting blade assembly 36 comprises an operating element in the form of a cutting element 42, and an attachment element 44. The attachment element 44 comprises a first portion 46 which is secured to the rotor 32 and a second portion 48. The second portion 48 carries a pivot bolt 50 for the cutting element 42, the pivot bolt 50 passing through an aperture 52 (seen in figure 5) in a mounting portion 54 of the cutting element, with sufficient clearance to enable the cutting element to pivot around the axis of the bolt 50. A retaining locking nut 56 is applied to the end of the bolt 50 together with a bearing washer 58.

The first portion 46 of the attachment element 36 lies between upper and lower flange portions 58, 60 on upper and lower rotor body parts 62, 64 respectively, being retained by one pair of a total of six bolts as indicated at 66, which pass upwardly through the flanges 60, 58 and carry nuts 68 at their upper ends.

The first portion 46 of the attachment element 36 lies in a plane which is perpendicular to the rotational axis 34 of the rotor assembly.

The second portion 48 of the attachment element 36 is inclined to the first portion 46 thereof, a fold line 70 between the two portions being inclined to a radial line extending from the rotational axis 34 to the pivot bolt 50 by which the cutting element is connected to the attachment element. The inclination of the fold line 70 is such that the portion 48 of the attachment element is inclined downwardly from its innermost end to its outermost end, and the upper surface thereof faces slightly forwardly with respect to the normal direction of rotation of the rotor assembly, which is anti-clockwise as viewed from above and as indicated by the arrow 72 in figure 4. It will also be appreciated that the axis of pivot bolt 50 about the cutting element 42 is able to pivot relative to the attachment element 36 is inclined outwardly relative to the rotational axis 34 (i.e. the distance between the axes increases with increasing distance above the ground which is being mowed) and also is inclined forwardly with respect to the normal rotational direction 72 with increasing distance above the ground surface.

The cutting element 42 comprises, in addition to its mounting portion 54, an operating portion 76. This operating portion 76 is inclined to the mounting portion 54 about a fold line 78, such that the operating portion 76 lies more nearly parallel to the ground surface than does the mounting portion 54, although it will be appreciated that the upper surface of the operating portion 76 is inclined slightly forwardly. The leading and trailing edges of an outermost part of the operating portion 76 are bevelled at 80 to provide cutting edge portions, the rearmost bevelled cutting edge portion being seen more clearly in figures 4 and 5 in respect of the cutting elements of the arms 38 and which are of exactly the same configuration as the cutting arm 36.

The rotor assembly further comprises an anti-scalping dish 84 whose lowermost point lies slightly beneath the normal operating level of the cutting elements of the assembly, to prevent the latter from digging into the ground if they come too close to it.

From consideration of the outward and forward inclination of the axis about which each of the cutting elements as 42 is pivotably connected to the respective attachment element as 36 by the pivot bolts as 52, it will be appreciated that if, in use, a cutting element encounters an obstruction of the ground and pivots backwards about the bolt 52, in doing so it is lifted above the ground level Thereby, the possibility of damage to the cutting element is substantially reduced. It will further be appreciated that, in addition to the downwards inclination of the second portions 48 of the attachment elements as 36, and the mounting portions as 54 of the cutting elements, the forward inclination thereof means that they act as fan blades creating upward air flow in use so that the vegetation which is being mowed, grass for example, is lifted to meet the cutting edges of the cutting elements. If the leading cutting edges of the cutting elements of the illustrated rotor assembly become damaged after long use, the cutting elements can be used on another rotor assembly whose normal direction of rotation is opposite to that illustrated, so that the undamaged rear cutting edges of the cutting elements then form the leading cutting edges of the other rotor assembly.

The above-described components of the mowing machine may be constructed of materials which are suitable for and generally used in corresponding components of machines known hitherto. In particular, the components of the rotor assembly, notably the cutting elements and their attachment members, may be of a suitable grade of sheet steel, formed to the required shape in suitable cutting and pressing operations. In known manner, the rotor assembly of the mowing machine may be provided with further attachment elements, with cutting elements at the outermost ends thereof, connected to the rotor in the opposite orientation to the cutting elements and attachment elements which have been illustrated, i.e. with the second portions of the attachment elements inclined upwardly rather than downwardly from the first portions so that the cutting elements at the ends thereon rotate some distance above the first cutting elements. These further cutting elements serve to chop vegetation cut by the first cutting elements, in a manner known for mowing machines.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for perlorming the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

Claims 1. A vegetation maintenance apparatus including a rotor which in use is driven to rotate about an axis extending generally perpendicular to a surface having vegetation which is to be maintained, and a number of operating elements pivotably connected to the rotor for operating on the vegetation, wherein each of the operating elements is connected to the rotor for angular movement about a pivot axis which is inclined outwardly (as herein defined) relative to the rotational axis of the rotor.
2. Apparatus according to claim I wherein the pivot axis is also inclined forwardly (as herein defined) relative to the rotational axis.
3. Apparatus according to claim I or claim 2 wherein each operating element comprises a mounting portion pivotably connected to the rotor, and an operating portion, the mounting and operating portions being inclined to one another.
4. Apparatus according to claim 3 wherein the operating portion of the operating element is inclined to the mounting portion thereof such that in normal use the operating portion or a part thereof lies generally parallel to the vegetation-bearing surface.
5. Apparatus according to any one of the preceding claims wherein the rotor is provided with attachment members to which the operating elements are pivotably connected.
6. Apparatus according to claim 5 wherein each attachment member comprises a first portion secured to the rotor and a second portion to which the respective operating element is pivotably connected.
7. Apparatus according to claim 6 wherein each attachment member is of sheet material, the first portion thereof lying in a plane generally perpendicular to the axis of rotation of the rotor, and the second portion inclined thereto to provide said inclination of the pivot axis of the operating member.
8. Apparatus according to claim 7 wherein the second portion of the attachment member is inclined so as to cause an upward airflow in the vicinity thereof when rotating in the normal in-use direction.
9. Apparatus according to any one of the preceding claims which is a mowing machine, and wherein the operating elements each include a cutting formation or formations on the operating portion thereof.
10. An operating element for a vegetation maintenance apparatus according to any one of the preceding claims, the operating element comprising a mounting portion and an operating portion, such portions being inclined to one another.
11. An operating element according to claim 10 for an apparatus according to claim 9, wherein the operating portion is provided with cutting formations at opposite edges which extend generally radially outwardly from the rotor when the operating element extends outwardly therefrom in normal use.
12. Vegetation maintenance apparatus, or an operating element therefore, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
13. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.