GB2312615A - Liquid applicator - Google Patents

Abstract

An applicator for applying a liquid, such as a weedkiller, to ground vegetation has an applicator member 4 which can be moved over the ground surface and which has an absorbent structure 5 which makes wiping contact with the vegetation. The absorbent structure 5 is provided by bristles of a rotation brush and the liquid is fed to the bristles from sprays 6.

Description

APPLICATORS This invention relates to an applicator for automated application of liquid substances to ground vegetation.

Traditional methods of applying liquid chemical substances to ground vegetation involve spraying. This can be costly, due to wasteful use of the liquid, and also the procedure may be undesirable from an environmental point of view. Moreover, spraying may not be wholly suitable in the case where selective application of the liquid is required, as for example where a weed killer is to be applied selectively to weeds growing amongst wanted vegetation such as grass.

As an alternative to spraying, for the selective treatment of weeds growing amongst grass, it is known to use a wick applicator which may be towed behind a tractor or other vehicle. This applicator has a large diameter static tube filled with weed killer liquid. Absorbent wicks project through holes in the side wall of the tube and these are moistened with the liquid by capillary action. The moistened wicks brush across the projecting weeds as the applicator is drawn across the ground surface.

This known wick applicator is effective but there are serious limitations on the operating speed. It is necessary to keep the operating speed low to give time for the liquid to be transferred to the wicks Another known weed killer applicator has a drum which is rotatable about a horizontal axis. The drum is covered in an absorbent layer which is moistened by liquid sprays which are directed onto the external surface of the layer. The rotating moistened surface of the covered drum is wiped across projecting weeds as the applicator is drawn across the ground surface.

This known drum applicator can be operated at an acceptable speed but there are problems of control.

The absorbent surface may not give good liquid-transfer contact with the weeds, and it can be difficult to ensure that the surface is maintained sufficiently moist for rapid application without being so moist as to give rise to dripping.

An object of the present invention is to provide an improved applicator with which high rates of liquid application can be obtained in an efficient and convenient manner.

According to the invention therefore there is provided an applicator, for automated application of a liquid substance to ground vegetation, said applicator comprising an applicator member which is supported for movement over a ground surface, said member having an absorbent structure thereto for wiping contact with vegetation on said ground surface, and a liquid supply device for supplying said liquid substance to said absorbent structure, characterised in that the applicator comprises a rotatable brush having bristles forming the said absorbent structure.

With this arrangement it is possible to attain good contact between the applicator and the ground vegetation and application of liquid substance to such vegetation can be achieved at a high rate in an efficient and convenient manner. This is because the bristles of the rotatable brush facilitate liquid-transfer contact with the vegetation, and the absorbent body of bristles facilitates rapid, controlled delivery of liquid,.

The brush preferably comprises equally spaced bristles, or tufts of bristles projecting radially around the entire periphery of a central elongate core in the form of a rod or tube, such bristles being close together to define an essentially continuous or closed cylindrical brush surface.

The absorbency of the brush may be derived from the liquid-retaining properties of the inter-bristle spaces and/or from the absorbent properties of the bristle material. Most preferably an absorbent material, such as a natural fibrous material, e.g. the material known as tampico, is used.

The brush is preferably mounted for rotation about a level or horizontal (or substantially horizontal) axis, or an axis parallel (or substantially parallel) to the ground surface. The brush may be power rotated e.g. by connection to a motor or engine, or it may be arranged to be rotated as it is drawn over the ground surface by frictional engagement with such surface e.g. by drivable connection to a ground engaging wheel.

The brush is preferably mounted so as to be height adjustable relative to the ground surface. In this way the brush can be set at a suitable height to facilitate selective application of the liquid substance e.g. to weeds projecting above grass.

The applicator may be arranged to be towed behind, or pushed in front of, a suitable vehicle such as a tractor or all terrain vehicle (ATV).

Thus the applicator may comprise a body structure with an attached rigid link, the body structure providing a support for the rotatable brush and the link providing means for connection to the vehicle. Where one or more ground engaging wheels are provided these may be mounted on the body structure.

With regard to the liquid supply device this may take any suitable form but preferably comprises a spray device having one or more spray outlets positioned adjacent the brush and connected to a source of the liquid whereby the liquid is sprayed externally onto the brush to be absorbed by the bristles.

The arrangement may be such that the liquid is fed by gravity from the source to the (or each) spray outlet. Thus, the (or each) spray outlet may be linked by one or more tubes to a liquid container mounted at a higher position than the spray outlets. Alternatively or additionally the liquid may be fed by a pump or the like driven in any suitable manner. An electric pump may be used.

The liquid source may be mounted on the abovementioned body structure or the link or on the vehicle.

Most preferably, provision is made for controlling the supply of liquid to the brush so that this can be matched to the speed of operation thereby to ensure that the brush is kept sufficiently moist for good transfer to the vegetation but is not so moist that dripping occurs to an unacceptable level.

To achieve this control, a control system may be provided which gives rise to intermittent supply of liquid to the brush with provision being made for variation in the duration of each period of supply and/or in the duration of gaps between periods of supply. User controls may be provided for effecting this variation. The variation may be implemented by use of a valve or valves and/or by use of a pump which is switched on and off.

Appropriate timing control circuitry may be used in conjunction with the valve or pump control arrangement.

The user controls may comprise separate adjustment controls or a single control which adjusts more than one parameter at the same time.

The applicator of the invention may be used for applying an aqueous contact weedkiller to weed leaves, such as a glycophosphate. However it is to be understood that the invention is not restricted to this and the applicator may be used for the application of any suitable liquid substance to any kind of vegetation for any suitable agricultural or horticultural purpose. Thus, plant growth control substances, insecticides and other substances may be used.

The invention will now be described further by way of example only and with reference to the accompanying drawing which is a diagrammatic perspective view of one form of an applicator according to the invention.

The illustrated applicator is intended to be drawn behind a tractor or other agricultural vehicle (not shown).

The applicator has a generally box shaped elongate metal body structure 1 which is open at the bottom to define an upturned trough.

At each end there is a rigid, fixed rearwardly projecting arm 2 each of which has a respective ground engaging wheel 3 freely mounted at its trailing free end.

Within the body structure 1 there is an elongate cylindrical brush 4 which comprises a central rigid core supporting equally spaced, closely positioned radially extending bristles 5 made from an absorbent natural fibre, white tampico.

The brush is rotatably mounted at its ends and is connected at one end by a respective drive belt to the respective wheel 3 whereby the brush rotates with the wheels.

Within the body structure 1 above the brush 4 there is a row of equally spaced downwardly directed spray nozzles 6 spaced above the surface of the brush 4.

These nozzles 6 are connected to a common pipe 7 which is connected to a container 8 of liquid in a manner yet to be described.

Shaped rigid bars 9 are fixed at pivot joints 10 at one end to the rear of the body structure 1. The bars extend over the body structure 1 and project forwardly of the body structure 1. The bars are fixed to the front of the body structure via a rigid upstanding link 1 1 at an adjustable position thereon.

The front ends of the bars 9 are, in use, connected to the rear of the tractor or other vehicle, and the link 11 is adjusted so as to adjust the height of the brush 4 above the ground surface by pivoting the brush 4 up or down about the wheels 3 and the pivots 10.

The container 8 is mounted at a convenient position on the back of the vehicle. The container 8 is a large plastics container which is filled with the liquid substance to be applied to ground vegetation. The container 8 is closed and contains a controllable electric impulse pump which is connected via a control system to electric supply on the vehicle.

The control system incorporates an electronic timer and has associated therewith manual controls. Conveniently this control system may be mounted on the container 8, although it may also be mounted elsewhere on the vehicle.

The control system has an on/off switch and also acts to set parameters of intermittent operation of the pump. That is, the pump is switched on for short periods with intervals therebetween and the duration of the periods and the intervals is adjusted. Typically the pump may be switched on for 6 second periods with a selected interval of 15 seconds to 6 minutes therebetween.

In use, the system is switched on so that the liquid substance is sprayed onto the brush 4 to saturate this. The material of the brush 4 may be such that it changes colour with liquid absorbency so that the user can tell visually when it is saturated.

During this phase, the control system may be set to give constant spraying, or spraying for long periods and/or with short intervals. This may be pre-set or there may be a start up setting which automatically achieves the correct setting.

As the applicator is drawn across the ground surface where the vegetation is to be treated, the control system settings are adjusted so that less liquid is supplied and the moisture content of the brush is maintained at say 85% to 90%, this being a suitable level for achieving efficient treatment.

The user may adjust the controls himself by reference to the colour of the brush or there may be preset control positions related to the application conditions, such as speed of movement, density of vegetation, etc.

With this arrangement, application can be achieved in a particularly effective, efficient and convenient manner. The brush can be readily maintained at the desired degree of wetness without undue risk of dripping, and good contact can be maintained with the vegetation to ensure efficient transfer of liquid thereto. Thus, selective application can be effected rapidly and without undue wastage of materials.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Thus, although reference is made to operation at 85% to 90% of moisture saturation, it is to be understood that in use, the degree of saturation may well fall well below this, perhaps as low as 60% or 40%.

Even at such lower levels the applicator still operates efficiently and effectively. It is an important advantage of the brush described that it has a high saturation capacity without dripping and even at lower levels of saturation it still contains considerable liquid which is freely available for transfer to the vegetation and which can be quickly and easily replenished.

The invention is defined herein with reference to a ground surface.

It is to be understood that this terminology is intended to be interpreted in a generalised sense meaning a base reference surface and is not necessarily restricted to a ground surface in the sense of a solid earth or land surface.

Thus, whilst it is visualised that the invention will find particular application in the context of agricultural or horticultural land, the invention may also find application in the context of golf courses, parkland and other grassed land, as also cobbled or gravel or brick or paved surfaces or the like. Moreover, the invention may also be applied to water or marsh surfaces such as canals, lakes, swampland and the like, in which case instead of wheels the applicator brush may be simply suspended above the water surface or may be supported thereon on floats or the like.

The applicator may also be self propelled instead of being towed or pushed by a connected vehicle. It may also be towed or pushed by a tow rope mechanism or any other suitable alternative to a vehicle.

In the case where application is to be made to a wide area, multiple applicators may be linked end to end and this may be done in such a manner that they can be set differently relative to each other e.g. to follow a ground contour.

Claims (17)

1. An applicator for automated application of a liquid substance to ground vegetation, said applicator comprising an applicator member which is supported for movement over a ground surface, said member having an absorbent structure thereto for wiping contact with vegetation on said ground surface, and a liquid supply device for supplying said liquid substance to said absorbent structure, characterised in that the applicator comprises a rotatable brush having bristles forming the said absorbent structure.

2. An applicator according to claim 1 wherein the brush has equally spaced bristles, or tufts of bristles, projecting radially around the entire periphery of a central elongate core.

3. An applicator according to claim 1 or 2 wherein the bristles are formed from a natural fibrous material.

4. An applicator according to claim 3 wherein the natural fibrous material is Tampico.

5. An applicator according to any one of claims 1 to 4 wherein the brush is mounted for rotation about an axis substantially parallel to the ground surface.

6. An applicator according to any one of claims 1 to 5 including power means for drivably rotating the brush.

7. An applicator according to any one of claims 1 to 6 wherein the brush is drivably connected to a ground engaging wheel so as to be rotated as it is drawn over the ground surface.

8. An applicator according to any one of claims 1 to 7 wherein the brush is height adjustable relative to the ground surface.

9. An applicator according to any one of claims 1 to 8 having a body structure with an attached rigid link, the brush being mounted on the body structure, and the link being adapted for connection to a towing vehicle.

10. An applicator according to claim 9 having one or more ground engaging wheels mounted on the body structure.

11. An applicator according to any one of claims 1 to 10 wherein the liquid supply device comprises a spray device having one or more spray outlets positioned adjacent the brush and connected to a source of the liquid.

12. An applicator according to claim 11 wherein the, or each, spray outlet is linked by one or more tubes to a liquid container mounted at a higher position than the spray outlets.

13. An applicator according to claim 11 or 12 including a pump for pumping the liquid to the, or each, spray outlet.

14. An applicator according to any one of claims 11 to 13 including a control system for effecting intermittent supply of the liquid to, the or each spray outlet.

15. An applicator according to claim 14 wherein the control system is adjustable to adjust the duration of supply and/ar the duration of gaps between periods of supply of the liquid.

16. An applicator according to claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

17. An applicator according to any one of claims 1 to 16 when used with glycophosphate weed killer.