| WO/2011/095757 | BRUSH BAR FOR A SURFACE TREATING APPLIANCE |
| WO/2000/051461 | METHOD FOR MOUNTING A DRUM AS WELL AS A DRUM AND AN AXLE FOR A BRUSH ROLLER |
| WO/2007/144066 | BRUSH AND SWEEPING DEVICE WITH BRUSH |
| CLAIMS 1. Brush element for use in a brush of a sweeping machine for the purpose of removing for instance dirt and/or weeds from or out of a surface, the brush element comprising: - a piece of wire cable, such as a piece of steel wire cable, with at least two wires which wears during use; - a layer which binds the wires of the wire cable and which is arranged at least round the wires and wears during use so as to expose the wire cable, and - at least one tear inhibitor associated with the layer and acting on the layer, which allows tearing of the layer substantially in accordance with wear of the wire cable, characterized in that the tear inhibitor is integrated in, on or under the layer. 2. Brush element as claimed in claim 1, wherein the tear inhibitor comprises at least one annular thickened portion of the material of the layer. 3. Brush element as claimed in at least one of the claims 1 and 2, further comprising at least one tear inhibitor of another material more tear-resistant than a material of the layer. 4. Brush element as claimed in at least one of the foregoing claims, wherein the layer is arranged at least on the wire cable by injection moulding, for instance in a mould. 5. Brush element as claimed in at least one of the foregoing claims, wherein the layer is formed from a material of a type such that at least the outer end of the brush element to be placed into contact with the street or the like has a predetermined flexibility. 6. Brush element as claimed in at least one of the foregoing claims, wherein the layer is manufactured from at least one material selected from the group comprising: natural and/or synthetic rubber; and plastic such as polyethylene. 7. Brush element as claimed in at least one of the foregoing claims, wherein the layer is manufactured from at least one biodegradable material . 8. Brush element as claimed in claim 7, wherein the material for the layer is selected from the group comprising: potato starch; biodegradable polyesters such as static, aliphatic aromatic copolyesters based on the diverse monomers of butanediol, polyesteramide (BAC); adipic acid and terephthalic acid; polyactic substances, including the A and the D variants, such as polyactic acid; compositions and substances based on polyhydroxybutyrate (PHB) and compositions and substances based on polyhydroxyalkanoate (PHA) ; and other substances such as starch. 9. Brush element as claimed in at least one of the foregoing claims, wherein at least two tear inhibitors are arranged at a distance from each other along the brush element. 10. Brush element as claimed in claim 7 or 8, wherein at least three tear inhibitors are arranged at a distance from each other along the brush element. 11. Brush element as claimed in claim 10, wherein the distance between the tear inhibitors corresponds to a rate of tearing of the layer and a rate of wear of the wire cable. 12. Brush element as claimed in at least one of the foregoing claims, wherein at least one longitudinal strengthening rib is arranged along the wire cable. 13. Brush element as claimed in at least one of the foregoing claims, wherein a web-like or net-like sleeve is arranged in, on or under the layer. 14. Brush element as claimed in claim 13, wherein the sleeve forms an integral part of the layer. 15. Brush element as claimed in at least one of the foregoing claims, wherein the layer comprises recesses and the tear inhibitor forms a reinforcement at the position of the recesses. 16. Brush element as claimed in claim 15, wherein the recesses are associated with centering means in an injection mould for the purpose of holding the wire cable centered in the mould during injection moulding of the layer round the wire cable. 17. Brush for a sweeping machine for removing dirt and/or for instance weeds from a surface, such as a street or the like, which brush comprises a brush body which is drivable in a movement and on which at least one brush element as claimed in a foregoing claim is arranged. 18. Sweeping machine for removing weeds from a street or the like, which sweeping machine comprises a brush as claimed in claim 17 and a drive for the brush and propelling means for displacement over a ground surface. 19. Brush element for use in a brush of a sweeping machine for removing dirt and/or weeds from or out of a surface, the brush element comprising: - a piece of wire cable, such as a piece of steel wire cable, and - a layer which binds the wires of the wire cable and which is arranged at least round the wires and wears during use so as to expose the wire cable, characterized in that the layer is manufactured from at least one biodegradable material. |
The present invention relates to a brush element for use in a brush of a sweeping machine for the purpose of removing weeds from the street or the like. In addition, the invention relates to a brush for a sweeping machine, the brush being provided with one or more brush elements according to the invention. Finally, the invention also relates to a sweeping machine comprising at least one brush according to the invention. Known brush elements usually consist of a piece of (steel) wire cable, i.e. a piece of cable consisting of strands of steel wire twisted together. In order to prevent rapid bending of the steel wires, or the brush elements beginning to unravel whereby they are no longer able to remove sufficient dirt and/or for instance weeds from a street, pavement or like surface, different solutions have been proposed.
A first known configuration is known from NL-A- 8702064. Each brush element is provided here in longitudinal direction with a number of clamping rings arranged at a distance from each other. A drawback of this known solution is that the clamping rings break loose from the brush elements during operation, which can result in hazardous situations, for instance for users and also bystanders.
Another known solution is to place a piece of plastic hose round the steel wire cable, for instance by pulling it over the cable, and attaching it to an outer end of the steel wire cable using a clamping bush. At this outer end the brush element is also fixed to a disc which can for instance be driven rotatably by drive means in a sweeping machine. A drawback of this known solution is that during operation the plastic hose tears close to the clamping bush, this causing imbalance of the brush.
Known from applicant's own disclosure NL-1018918 is that a brush element is formed from a cable with a layer binding wires of the cable . From the publications acknowledged as most closely related prior art, US-4 , 144, 610 and WO-2008/077, 777, it is known to arrange a first jacket of polyethylene and a second jacket of polyurethane round the wire cable, for instance by means of extrusion, in order to prevent unravelling of wire cable with the second jacket.
The present invention has for its object to improve a brush element for use in a brush of a sweeping machine for removing dirt and/or for instance weeds from the street or a like surface. It has been found that, even when a layer binding the wires of the cable is applied, this can tear, and does so at a rate which can be far different from the wear to the wires of the cable. The wires can thus still become exposed along a considerable length, and the wires can still become unravelled to an undesirable extent. It is an object of the present invention to obviate or at least alleviate this phenomenon, substantially without applying considerably thicker layers or more expensive, higher-grade plastics and/or environmentally-unfriendly materials as in the closest prior art, as this would adversely affect the effectiveness and the effect on the environment.
For this purpose the brush element, the brush and the sweeping machine according to the invention are characterized not only in that the brush element comprises a piece of wire cable and a binding layer on the wires of the cable, but also in that at least one tear inhibitor is provided in association, preferably close association, i.e. in integrated manner in, on or at the layer.
The layer is connected to the wire cable along a considerable part of the length of the brush element and imparts thereto a holding- together effect, so reducing to a minimum the danger of in any case detachment, and in particular breaking loose with force. In addition, the tear inhibitors maintain the cohesion between the layer and the wire cable, even if the layer itself is already torn over some distance.
The use of less high-quality materials in the layer has become possible by applying the tear inhibitor (s) . Less wear-resistant materials can particularly be applied, while the highly wear- resistant materials according to the known art usually have a great environmental impact. Softer materials can thus usually be applied, particularly with and due to the use of the tear inhibitor (s) , and the choice of environmentally- friendly biodegradable materials herein provides per se a solution to the problem underlying the present invention. With or without tear inhibitor (s) materials can be applied which can be more brittle, but which can also be as hard and stiff as the plastics applied in the known art, wherein the use of particularly the biodegradable materials provides a solution.
In a possible embodiment discrete tear inhibitors are arranged or provided distributed along the length of the brush element. Conversely, a single tear inhibitor can be arranged along at least part of the length of the brush element, for instance in the form of a net or the like. The rate at which the tear inhibitors then give way under the pressure of the sweeping, and allow further tearing of the layer, can then correspond or be made to correspond to a rate at which the wire cable of the brush elements wears, without appreciable unravelling occurring here .
The integration of the tear inhibitor has, among others, production engineering advantages . During production a mould can be applied for the purpose of arranging the layer. The mould can hold the tear inhibitor (s) when material for forming of the layer is carried into the mould. The layer can be arranged with a co-extrusion process, and segments or parts of the layer can then be formed from a material which differs from the rest of the layer and which can be fed at intervals to an extruder. The tear inhibitor (s) can comprise at least one annular thickened portion on, in or under the layer. Compared to a layer alone, the thickened portion per se can then, with a minimum of additional use of material, provide for an effective limitation of tearing of the layer. In yet another embodiment the brush element according to the invention further comprises at least one tear inhibitor of another material which is more tear-resistant than a material of the layer.
The layer of plastic is preferably arranged on the wire cable by injection moulding, for instance in a mould. The piece of wire cable is placed in a cavity in an injection moulding machine and plastic is then moulded around the wire cable in the injection moulding cavity. At least one tear inhibitor can be arranged in the cavity prior to or during the injection moulding. Another material can be applied in an extrusion process. After cooling, a wire cable bound by the layer with tear inhibitors is obtained, and thereby a brush element according to the present invention. The plastic is preferably of a type such that at least the outer end of the brush element to be placed into contact with the street or the like has a predetermined flexibility. During operation the brush element can thus properly follow the surface of the street, pavement and the like. In a preferred embodiment the plastic is formed from at least one of the materials from the group comprising: rubber, either natural or synthetic rubber; polyethylene and other materials. Polypropylene in particular is sufficiently wear-resistant and gives the final brush element the desired flexibility. The improved tear-resistance is provided by the tear inhibitors.
A brush element according to the invention very preferably has the feature that the layer is manufactured from at least one biodegradable material selected from the group comprising: potato starch; biodegradable polyesters such as static, aliphatic aromatic copolyesters based on the diverse monomers of butanediol, polyesteramide (BAC) ; adipic acid and terephthalic acid; polyactic substances, including the A and the D variants, such as polyactic acid; compositions and substances based on polyhydroxybutyrate (PHB) and compositions and substances based on polyhydroxyalkanoate (PHA) ; and other substances such as starch. Many other biodegradable materials can be applied within the scope of the invention, which can then optionally be of natural or synthetic origin. Material of the layer worn away from the brush element then results in a negligible environmental impact, this resulting in great advantages compared to other materials often having a high environmental impact such as have formerly been applied. A brush element according to the present invention preferably also has the feature that at least two tear inhibitors are arranged at a distance from each other along the brush element. The distance between the tear inhibitors can then be selected in accordance with the rate at which the layer tears and the rate at which the wire cable wears.
A brush element with a layer of biodegradable material preferably comprises at least three tear inhibitors. Such materials are generally less wear-resistant and/or tear-resistant. For materials with less resistance to wear and tear, such as some, if not many, of the biodegradable materials, it is then preferably the case that more tear inhibitors have to be arranged than if materials are applied, in general more synthetic materials, which are better able to withstand these mechanical influences . The use of more tear inhibitors can then result in a better matching of the tearing rate of the layer and the wearing rate of the wire cable. It is strongly recommended here that the distance between the tear inhibitors corresponds to a rate of tearing of the layer and a rate of wear of the wire cable. Unravelling of the wire cable can then be optimized, and the tear inhibitors give way at a rate at which the wire cable wears .
In yet another preferred embodiment of the invention at least one longitudinal strengthening rib is arranged along the wire cable. This contributes in positive manner toward a less rapid detaching of the layer from the wire cable.
On the basis of the same or similar considerations and objectives, the brush element according to the invention can also be provided with a web-like or net-like sleeve in, on or under the layer. In such an embodiment it is favourable when the sleeve forms an integral part of the layer, just as the tear inhibitors preferably also form an integral part of the layer.
In another preferred embodiment the layer comprises recesses and the tear inhibitor forms a reinforcement at the position of the recesses. Such recesses can for instance be associated with centering means in an injection mould for the purpose of holding the wire cable centered in the mould during injection moulding of the layer round the wire cable. The tear inhibitors then have a dual function: influencing the rate at which the layer tears and preventing any increase in the inherent weaknesses of these recesses .
Within the scope of the problem formulated in the present invention a brush element according to the invention, as alternative or as addition to the tear inhibitor, has the feature that the layer is manufactured from at least one biodegradable material . Many biodegradable materials can be applied within the scope of the invention and can optionally have a natural or synthetic origin. Material of the layer worn away from the brush element then results in a negligible environmental impact, and this results in great advantages compared to other materials often having a very high environmental impact such as have formerly been applied. Further provided according to the invention is a brush for a sweeping machine for removing dirt and/or for instance weeds from a street or like surface, which brush comprises a brush body which is drivable in a movement and on which at least one brush element according to an aspect of the invention is arranged. Also provided according to the invention is a sweeping machine for removing dirt and/or for instance weeds from a street or the like, which sweeping machine comprises such a brush with at least one brush element according to the invention. The invention will now be further elucidated with reference to the accompanying drawings . In the drawings :
Figure 1 shows a schematic perspective view of a sweeping machine with a brush and brush elements according to the present invention; Figure 2 shows a brush for a sweeping machine with a number of brush elements according to the invention;
Figures 3, 4 and 5 each show a partially cut-away perspective view of another embodiment of a brush element according to the invention; Figure 6 shows a view of a brush element with a longitudinal thickened portion, being a rib or reinforcement as embodiment of a tear inhibitor according to the invention; and
Figure 7 and figures 8 and 9 show respectively a brush element and an associated production method in an alternative embodiment to the above embodiments.
Figure 1 shows a sweeping machine 10 with a brush 1 on a pivot arm 9. The sweeping machine 10 itself comprises a frame having thereon a cab 11 and a trailer 12 for carrying containers 13 thereon or therewith. The containers can contain herbicides, or preferably just flushing water. Alternatively or additionally, one or more than one of containers 13 can be utilized for temporary storage of dirt swept loose with brush 1. In such a case a suction nozzle (not shown) is arranged at the brush. The container or containers 13 can also contain spray water, wherein a spray nozzle (not shown) is arranged at brush 1 in order to spray the spray water at brush 1 and thus prevent dust formation. A conduit 14 runs between containers 13 via pivot arm 9 to brush 1. When brush 1 and sweeping machine 10 are applied in the context of weeds control, it is clearly advantageous to be able to apply herbicides, or just flushing water, to a surface which has been swept or is to be swept . These advantages then relate to keeping clean the surface, street or road where the sweeping machine has been employed. In addition to conduit 14, a hydraulic conduit can be arranged along pivot arm 9 for driving a hydraulic motor (not shown) at the brush for the purpose of rotary driving of brush 1. In an embodiment without containers 13 the conduit 14 can be the hydraulic conduit to the hydraulic motor. The pivot arm is arranged on cab 11 by means of a hinge 15 and can be placed in a desired position by means of pull rods 16 which can be driven in the direction of double arrows A to enable setting of the position of arm 9 and of brush 1 relative to the frame of sweeping machine 10. Pull rods 16 can be formed by cylinders.
Figure 2 shows a brush 1 for a sweeping machine 10 for removing dirt and/or for instance weeds from a street or like surface. Brush 1 comprises a rotatably drivable disc 2. Driving of disc 2 takes place by means of a transmission (not shown) extending along or in arm 9. Disc 2 is provided with a number of brush elements 3 arranged distributed over the periphery. Each brush element 3 has a free outer end 4 which is placed into contact with the street or pavement or other surface for the purpose of removing dirt and/or for instance weeds. The opposite outer end 5 of each brush element 3 is secured, for instance welded, to disc 2.
Figure 3 shows a possible embodiment of a brush element according to the invention. Brush element 3 comprises a piece of steel wire cable 6 received in a clamping bush 7. Clamping bush 7 is located at the outer end 5 of brush element 3 fixed to disc 2 of brush 1. Brush element 3 further comprises a layer 8, for instance of plastic, binding the steel wires of cable 6. This layer of plastic 8 is arranged round the piece of steel wire cable, for instance by means of injection moulding or extrusion or the like, such that the material of layer 8 lies between and around the steel wires of cable 6 and is, as it were, formed integrally therewith. Outer end 4 of brush element 3, which is placed into contact with the street or similar surface, is further provided during mounting of brush element 3 in brush 1 with a plastic layer 8 for the purpose of protecting the person attaching brush elements 3 to brush 1. This layer of plastic 8 will, through contact with the street or the like, wear rapidly and expose the outer end of steel wire cable 6 for removal of weeds or sweeping away other dirt. The plastic is preferably polyethylene or another plastic or other optionally natural material such as rubber, with properties such that at least the outer end 4 of brush element 3 is or remains to greater or lesser extent flexible so that it can follow the surface of the street, pavement, and particularly transitions therebetween. Polyethylene has the additional advantage of being relatively wear-resistant .
Layer 8 comprises thickened portions 17 which, precisely because of the greater thickness compared to other parts of layer 17, have a greater tear resistance. For this reason the thickened portions are deemed tear inhibitors in the sense of the present invention. The thickened portions are arranged at mutual distances which are related to wear of cable 6 when it comes into contact with a street or road or other surface. The rate at which tearing in the layer progresses along tear inhibitors 17 can thus be made to correspond to wear of cable 6, this so as to prevent cable 6 being stripped of layer 8 and becoming exposed over distances such that cable 6 begins to unravel .
Figure 4 shows an alternative embodiment of a brush element 19. Tear inhibitors are formed therein by bands 18 which are incorporated into the thickness of layer 8 without thickened portions as in the embodiment of figure 3. Band 18 can be formed from a different material than the other parts of layer 8. The same material, but having for instance a higher density, can also be applied to form bands 18. The bands can be trained round cable 6 before the other parts of layer 8 are arranged, and an adhesion can be formed therebetween if for instance a thermoplastic material is applied and heated in order to cause fusion of layer 8 and bands 18. Other methods of integrating bands 18 or thickened portions 17, or later imparting a cohesion with layer 8 after layer 8 has been arranged, also fall within the scope of the present invention.
Figure 5 shows a further alternative embodiment which comprises a web-like sleeve 20, web 20 being arranged round a layer 8 in a brush element 21 according to the present invention. Sleeve 20 can form a continuously closed sheath all around or also - as shown in figure 5 - take a net or web form in order to save material . Sleeve 20 is preferably an integral part of the layer, although the invention is by no means limited hereto, and sleeve 20 can be a component which is separate from layer 8.
Figure 6 shows an alternative embodiment based on the embodiment of figure 4 with integrated tear inhibitors 18 in layer 8. Arranged on layer 8 and over tear inhibitors 18 is at least one longitudinal thickened portion 23, preferably of the same material as that of layer 8 and/or of bands 18 forming tear inhibitors. A single longitudinal thickened portion 23 can be arranged in the embodiment of a brush element 22 shown in figure 6, although diverse thickened portions 23 can also be arranged in longitudinal direction on or over or in the material of layer 8. If more than one thickened portion 23 is provided, thickened portions 23 are preferably distributed radially over the periphery of the thus formed brush element 22. Such a longitudinal reinforcement can of course also be applied in an embodiment such as that shown for instance in figure 3, whereby an embodiment can result similar to that of figure 5. If however thickened portions 17 or superposed bands 17 of figure 3 are connected or form a unit with thickened portions 23 in figure 6, there then results not a net or web form with an inclining orientation but one in which the bands are oriented radially round the periphery and thickened portions 23 have a purely longitudinal orientation.
It is likewise and equally possible per se to also arrange purely longitudinal thickened portions 23 in the embodiment of figure 5 in order to improve the cohesion of the tear inhibitors. The thickened portion 23 in figure 6 or any other above stated variant can also be incorporated in the interior of layer 8, for instance by choosing a suitable material during co-extrusion or injection of a suitable material variant in an injection mould. The advantage hereof is that the outer surface of layer 8 of the brush element is flat, smooth and round, this in contrast to the thickened portions 23 in figure 6.
Figure 7 shows a further variant. In this variant specific account is taken of the production process for arranging a layer 8 on or over cable 6, in particular with an injection moulding process wherein an injection mould is applied. This is because it is desirable in such an embodiment to align cable 6 centrally in the injection mould, or at least the cavity therein, in order to ensure that the material of layer 8 is well distributed around cable 6. As shown in figures 8 and 9, a mould 25 is applied here having centering protrusions 26 therein. Centering protrusions 26 provide for an alignment and centering of a cable 6 for the purpose of defining a space 27 in which the material for layer 8 can spread in order to cover cable 6 in the desired manner with the material for layer 8. Embodiments can be envisaged wherein protrusions 26 are located at a distance from the tear inhibitors, for instance tear inhibitors 17 in figure 3. The recesses which result from centering protrusions 26 then however represent weakening in layer 8. Such weakened portions, such as recesses 28 in the embodiment of a brush element 24 in figure 7, can serve to further regulate tearing and wear. When such recesses are formed just below a tear inhibitor, tearing will then usually follow the weakened portions formed by centering protrusions 26. This can be prevented with a configuration as shown in figure 7, which can be realized or obtained with mould 25 of figures 8 and 9. The tear inhibitor is thus formed here by providing an extra-large cavity 27 along the length of cable 6 and by positioning the centering protrusions therein. This results in a thickened portion 29 on the outer surface of brush element 24 in figure 7 with recesses 28 therein resulting from the presence of centering protrusions 26 in figures 8 and 9. These centering protrusions 26 are situated in mould 25 in an additional cavity 30 which forms bands 17 and with which thickened portions 29 in figure 7 can be manufactured. Protrusions 26 provide the recesses 28. The additional material of thickened portions 29 preferably at least compensates for the weakened portions 28, so that tearing or wear of layer 8 is at least not accelerated by the presence of recesses 28 at a position other than at or in the tear inhibitors. As noted, an alternative embodiment can also be applied wherein the weakened portions 28 lie above or just below tear inhibitors 17, depending on the manner in which synchronization or matching is realized or is intended between the rate of wear of cable 6 and tearing or wear of layer 8. In the embodiment of figure 7, be it with a mould other than that shown in figures 8 and 9, use can also be made of another configuration of layer 8, as is shown for instance in figure 4 or 5, and the pattern of the tear inhibitors in combination with the weakened portions resulting from the centering protrusions can be regulated in random manner.
It is further also noted that the material of in any case layer 8, and preferably also of tear inhibitors 9, is biodegradable. The skilled person is familiar with a wide diversity of materials for this purpose from which it is possible to choose. In a particular preferred embodiment use can be made of potato starch (as raw material} for the manufacture of layer 8. In such embodiments, in which many other materials can also be applied, material torn away or torn in or broken off layer 8 will not have any environmental impact. This is because the material of layer 8, and preferably also of the tear inhibitors, is of biodegradable material.
It is known that biodegradable material is usually less well able to withstand mechanical influences and loads. Particularly when used in the outside air, the biodegradable material of layer 8, and preferably also of the tear inhibitors, will regularly come into contact with rain and other factors which are conducive to or accelerate the process of biodegradation. It is therefore assumed that such materials have greater need of strengthening, and tearing or wear thereof must be countered in greater measure . It is precisely in such embodiments with biodegradable material as layer 8, and preferably also as the tear inhibitors, that it is therefore recommended to use more tear inhibitors than in the case of mechanically stronger materials, and it is precisely here that it is then advantageous to arrange at least one, preferably two and more preferably at least three tear inhibitors along the length of the brush elements. It is also the case here that, of the diverse embodiments of tear inhibitors, it makes no difference whether they are realized in the layer, on layer 8 or thereunder, as long as this is not a limitation imposed on the present invention, or at least this is not the case in the claims.
After examination of the foregoing many other alternative and additional embodiments will occur to the skilled person within the scope of the definitions of the appended claims, which then do not fall within the scope of protection of the present invention defined by the claims only when they differ considerably therefrom in letter or spirit. It is thus possible for a web- like embodiment of a tear inhibitor without thickened portions to be incorporated in the material of layer 8. The stated materials are in no way intended as limitation - all materials which can withstand wear to the desired extent can suffice for layer 8. The same materials can be applied for the tear inhibitors as for layer 8, albeit with other properties, such as the density thereof, or other materials can be applied for tear inhibitors 17, 18 and 20 than for layer 8. The brush elements need not necessarily comprise an outer end 4 encapsulated with material of layer 8, although this can have evident advantages for fitters. Nor do the brushes need to have a clamping bush 7 on the outer end 5 directed toward brush body 2; a layer 8 from top to bottom over, on or in cable 6 can suffice to produce a brush element according to the invention.
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