EP0084345A2 - Brush attachment for a vacuum cleaner - Google Patents

Abstract

The brush (1) has a brush bearer (2) and brush elements (4) which are inserted in receiving chambers (3) of the brush bearer (2), the latter being constructed as a brush roller and the brush elements (4) being arranged in a helical manner on the brush bearer (2). In order to guarantee as low wear as possible on the brush elements (4), each brush element (4) consists of a bar-type brush head (5) made of material which is highly resistant to wear and a brush foot (6) which can be inserted in the receiving chamber (3) of the brush bearer (2). The brush head (5) is designed as a rectangular metal bar, whereas the brush foot (6) consists of an elastic plastic material. On one side, the brush head (5) is embedded in the brush foot (6). In order to form an intended bending point (7), the brush foot (6) has a cross-sectional constriction (9) outside the receiving chamber (3). <IMAGE>

Description

The invention relates to a brush for a brush attachment of a vacuum cleaner, with a brush holder designed as a brush roller and brush elements used in receiving chambers of the brush holder, the brush elements being arranged helically on the brush holder.

A "classic" brush attachment, i.e. H. a brush attachment with a fixed brush provided with tufts of bristles practically exerts a so-called "sweeping effect". The surface of the carpet is essentially cleaned of dust and dirt. Modern brush attachments do not have a fixed brush, but rather a rapidly rotating brush with a brush holder in the form of a brush roller, which can be set in rotation by a drive. With such a modern brush attachment not only larger dirt particles can be picked up from the floor - "sweeping effect" - so that they can be easily vacuumed off, but the poles of the carpet or carpet can be opened by the brush elements of the rapidly rotating brush holder, so that they can also move deeper between them Carpet loops of dirt that have penetrated are thrown out and can easily be carried away by the suction flow. With such a modern brush attachment, in addition to the classic "sweeping effect" (carpet sweeper), an additional "gatekeeper effect", which is very important for the cleaning effect of a carpet, is achieved.

The present invention relates in particular, although not exclusively, to the design of a brush for an electrical brush attachment of the type explained above.

In the known brush from which the invention is based, the brush roller is made of wood. The receiving chambers for the brush elements are simple blind holes into which the brush elements are glued. Tufts of bristles made of natural bristles, possibly with Perlon or other synthetic fibers, are used as brush elements. Because of the "gatekeeper effect" explained at the beginning, it is necessary to press the brushes of a brush attachment of the type explained above relatively firmly onto the floor. Leading to the fact that the bristle brush elements wear out quickly. This wear manifests itself in the fact that the length of the bristle tufts decreases rapidly and that the bristle tufts are spread apart.

In order to compensate for the previously explained wear effect in previously known brushes, it is known to provide mostly electronically operating wear indicator devices and manually actuable lowering devices, with the aid of which the brush can be lowered depending on wear until the brush elements are completely worn out and the brush must be replaced. Such wear indicators and manually operable lowering devices are technically and economically up wendi ^g. In addition, the decreasing length of the tufts of bristles means that the deflection at the tip of the tufts of bristles decreases with increasing wear and thus the effective contact pressure becomes higher.

Starting from the previously described prior art, the invention has for its object to provide a brush in which there is practically no wear of the brush elements, so that wear indicators and manually operated lowering devices of the type explained above do not have to be provided when they are used.

The brush according to the invention, in which the above-mentioned object is achieved, is first characterized in that each brush element consists of a bow-like or sheet-like brush head made of highly wear-resistant material and a brush foot that can be inserted into the receiving chamber of the brush holder. According to the invention, bristle tufts are no longer used as brush elements, but rather specially designed elements which consist of the brush head and brush base. The brush head of each brush element is designed so as to be bow-shaped or sheet-like that both the "sweeping effect" explained at the beginning and the "gatekeeper effect" explained at the beginning can be optimally achieved. It has been shown in studies that the bow-like or sheet-like design of the brush head is almost an optimum here. This brush head can easily be made of highly wear-resistant material. The special design of the brush head leads to the fact that this can not necessarily be optimally attached to the brush holder. This is where the function of the brush foot occurs, which can be optimized with regard to the attachment to the brush holder.

There are, of course, a large number of possibilities for the design of the brush head within the framework of the inventive concept explained above. By way of example only, it should be stated that the brush head can be designed as a preferably rectangular metal bracket, that the brush head can also be designed as a metal tongue or finally as a plastic bracket or plastic tongue.

Practical tests have shown that the previously described brush according to the invention is not yet able to achieve optimum stability. Without further measures, the brush head breaks off the brush base too easily. For this reason, another teaching of the invention, which is of particular importance, is to provide a predetermined bending point on the brush head, on the brush foot and / or between the brush head and the brush foot. Such a predetermined bending point ensures that the alternating bending stresses that constantly occur during the brushing process, which are particularly significant at high speeds of a brush holder designed as a brush roller, are practically only effective in the area of the predetermined bending point. This predetermined bending point can be designed specifically to accommodate these alternating bending stresses. In addition, this predetermined bending point must be dimensioned so that the brush element has a suitable bending stiffness overall. The bending stiffness of the brush element is of crucial importance for the previously described "gatekeeper effect". A further advantage is achieved in the brush according to the invention in that the deflection of the brush elements remains completely unchanged. In the previously known brushes with tufts of bristles as brushing elements, a defined deflection that was unchanged over long periods of time could not be achieved because of the shortening of the brushing elements associated with the wear of the brushing elements. In the brush according to the invention, the constant bending stiffness of the brush elements in connection with the unchanged deflection of the brush elements leads to the result that the contact pressure the brush elements on the corresponding carpet remains constant. Finally, for the reasons explained above, the effective restoring force of the brush elements is also constant.

Is the brush head designed as a metal bracket; it is advisable to loop this metal bracket to form the predetermined bending point. The loop-shaped guidance of the metal bracket, i.e. H. in the case of a substantially rectangular metal bracket, one loop on two opposite sides of the metal bracket, leads to the fact that the alternating bending stresses are absorbed elastically in the areas of the loops. The spring stiffness depends on the size of the loops and varies depending on the direction of the alternating bending stresses.

As far as the brush foot is concerned, this too, like the brush head, may consist of an elastic plastic. If the brush base is made of an elastic plastic and the brush base has an area lying outside the receiving chamber of the brush holder, the brush base can have a cross-sectional constriction in the area outside the receiving chamber to form the predetermined bending point. The exact design of the cross-sectional constriction depends on the expected operating conditions and loads, but can be easily adapted to all requirements, especially when using an elastic plastic.

If the brush base is made of an elastic plastic, the brush head can be embedded on one side in the brush base. This is particularly advantageous in terms of production technology and application technology, in particular if the brush head is designed as a metal bracket or metal tongue. On the other hand, the brush head and the brush base can also be formed in one piece with one another, in particular if the brush head is designed as a plastic tongue. The latter naturally also applies if the predetermined bending point is provided as a separate part or in a separate part between the brush head and the brush base.

With regard to the choice of materials, there are only minor problems when using metal. Correspondingly elastic materials that meet operational requirements are widely known here. When using plastic, however, the problem of electrostatic charging must also be considered in addition to the questions of elasticity. Depending on the choice of material, the brush head and / or the brush base must be made of a tough plastic that cannot be charged electrostatically or practically not, preferably polyurethane, rubber, Teflon, a plastic that contains a lot of Teflon, or the like. The listing of rubber in this list makes it It is clear that natural substances may also be considered, provided they meet the requirements for elasticity, toughness, etc.

With regard to the choice of plastic, it is also of particular importance that the plastic should be capable of being injection molded, injection molded or extruded and should have a low coefficient of friction. In the latter point, teflon or a material that contains a lot of teflon is of particular advantage.

There are, of course, a large number of possibilities for fastening the brush base of a brush element in the corresponding receiving chamber of the brush holder, which can only be explained here in individual examples. For example, the brush foot can be fixed in the receiving chamber by an obliquely driven nail. On the other hand, the brush foot can also have laterally projecting fastening widenings, through which nails can then be driven more or less vertically into the material of the brush holder. Furthermore, an embodiment is also possible in which the brush holder has steps extending in the radial direction, to which the brush base of the respective brush element can be attached by nails which are driven in substantially tangentially. Finally, it is of course also conceivable that the brush base of a brush element is pressed or clamped into the receiving chamber of the brush holder or glued therein.

The individual brush element in the brush according to the invention can be functionally divided into three areas. The actual "sweeping effect" is achieved in the work area, which essentially comprises the brush head. In the bend area, the brush element is designed so that, in connection with the brush head, ie the work area, the "gatekeeper effect" can be realized in an optimal manner. In the bending area, the brush element is designed so that it can withstand the alternating bending stresses that occur for very long periods of time. Finally, in the holding area, the bending element of the brush according to the invention is designed such that it can be optimally connected to the brush holder in terms of fastening technology. The three clearly distinguishable functional areas in the brush element of the brush according to the invention are realized in such a simple manner that even large-scale production of the brush according to the invention is economically possible.

In the brush according to the invention, the brush elements, as in the previously known brushes, are preferably arranged helically on the brush holder, so that the torque to be applied by the drive fluctuates as little as possible. In terms of production technology, it is particularly advantageous here if a plurality of brush elements are combined in one brush part and the brush part is fastened in a helical manner on the brush holder. This configuration is particularly recommended when using plastic. The brush holder must, of course, be provided with appropriate receiving chambers, whereby the alternatives previously explained for the individual brush elements also apply to the attachment of the brush part consisting of the plurality of brush elements to the brush holder.

Since wear of the brush elements does not occur or practically does not occur in the brush according to the invention, it is achieved beyond the extension of the operating life of a brush according to the invention that wear indicator devices etc. for lowering the brush attachment do not have to be provided. This represents a considerable technical and economic comparison einfachun ^g. In addition, both the. The "sweeping effect" and the "gatekeeper effect" are optimally fulfilled, although the economic outlay for producing the brush according to the invention is extraordinarily low owing to the skillful construction of the brush elements.

The following sequence of steps is recommended as a very advantageous possibility for producing brush elements for a brush of the type explained above.

First, a large number of U-shaped metal brackets or metal tongues are geometrically strung together and thus connected to one another. The geometric stringing together can be carried out by means of an elongated metal strip to which the metal brackets or metal tongues are soldered, clamped or otherwise fastened. The metal brackets or metal tongues are then provided at the end with the brush feet, for example encapsulated or cast with a corresponding plastic. After this joining process, the brush elements are then finally separated. Further manufacturing methods result from the patent claims 14 to 16.

• Fig. 1 in schematischer, stark vereinfachter Darstellung ein erstes Ausführungsbeispiel einer erfindungsgemäßen Bürste,
• Fig. 2 ein zweites Ausführungsbeispiel einer erfindungsgemäßen Bürste in einer Fig. 1 entsprechenden Darstellung,
• Fig. 3 ein Bürstelement für eine Bürste gemäß Fig. 2,
• Fig. 4 den Gegenstand nach Fig. 3 in einer Seitenansicht,
• Fig. 5 einen Metallstreifen mit einer Mehrzahl von Metallbügeln zur Herstellung von Bürstelementen,
• Fig. 6 ein Bürstelement, hergestellt mit einem Metallstreifen gemäß Fig. 5 und
• Fig. 7 ein weiteres Ausführungsbeispiel eines Bürstelementes für eine Bürste gemäß Fig. 2.

In the following, the invention is explained in more detail with reference to a drawing which only shows exemplary embodiments; it shows

• 1 is a schematic, highly simplified representation of a first embodiment of a brush according to the invention,
• 2 shows a second embodiment of a brush according to the invention in a representation corresponding to FIG. 1,
• 3 shows a brush element for a brush according to FIG. 2,
• 4 shows the object of FIG. 3 in a side view,
• 5 shows a metal strip with a plurality of metal brackets for producing brush elements,
• Fig. 6 is a brush element, made with a metal strip according to FIG. 5 and
• 7 shows a further embodiment of a brush element for a brush according to FIG. 2.

The ^g in Fi. 1 shown brush 1 is intended for a brush attachment of a vacuum cleaner, namely for an electric brush attachment. This brush 1 accordingly consists of a brush holder 2 designed as a brush roller and a multiplicity of brush elements 4 inserted in receiving chambers 3 of the brush holder 2. The brush elements 4 are arranged helically on the brush holder 2, which is indicated in FIG. 1.

As clearly shown in FIG. 1, each brush element 4 has a bow-like brush head 5 made of a highly wear-resistant material, namely metal, and a brush foot 6 that can be inserted into the receiving chamber 3 of the brush holder 2. The brush head 5 is designed as a substantially rectangular metal bracket. A predetermined bending point 7 is provided on the brush head 5. At the predetermined bending point 7, the alternating bending stresses of the brush element are recorded during operation. For forming the predetermined bending point 7 of the brush head is looped 5, ie in each case a loop 8 is found we ^g directed sides of the brush head 5 at both of the brush carrier. 2

1 further shows that the brush head 5 is embedded on one side in the brush base 6.

In the exemplary embodiment of a brush 1 according to the invention shown in FIG. 2, the brush head 5, as in the exemplary embodiment explained above, is designed as a rectangular metal bracket. The brush base 6 here consists of an elastic plastic and has a cross-sectional constriction 9 to form the predetermined bending point 7 in an area lying outside the receiving chamber 3.

The brush element 4 according to FIG. 2, consisting of the brush head 5 and the brush base 6, can be seen more precisely in FIGS. 3 and 4. As shown in Fig. 3, the Brush head 5 embedded on one side in the brush base 6, essentially above the cross-sectional constriction 9 of the brush base 6. The brush head 5, designed as a substantially rectangular metal bracket, is inserted obliquely into the brush base 6, so that the free ends of the brush head 5 in the area of the Cross-sectional constriction 9 emerge laterally from the brush foot 6. These ends are bent there for better attachment. This construction leads to the fact that the stiffness of the spring formed by the brush base 6 in the direction of the arrow (FIG. 4) is greater than in the opposite direction of the arrow. The main bending direction is in the direction of the arrow, so that such a brush element 4 is to be arranged on the brush holder 2 in such a way that the movement of the brush head 5 takes place over a carpet in the opposite direction of the arrow in FIG. 4.

FIG. 5 shows a plurality of metal brackets 10 which are attached to an elongated metal strip 11. In each case a metal bracket 10 and the associated area of the metal strip 11 form a brush head 5 for a brush element 4. The brush feet 6 to the brush heads 5, each consisting of a metal bracket 10 and the corresponding area of the metal strip, are produced in that the ones connected to the metal strip 11 Areas of the metal bracket 10 and the associated areas of the metal strip 11 are encapsulated with a plastic of the appropriate shape. Then the metal strip 11 is then separated between the individual metal brackets 10, as a result of which the brush elements 4 are separated. 6 shows what such a brush element 4 looks like in the finished state.

In the brush element 4 shown in FIG. 6, in comparison to the brush element 4 shown in FIG. 4, it is striking that different bending directions do not exist, but rather that in both possible bending directions the spring formed by the brush foot 6 has the same rigidity.

Looking at Fig. 7, it can be seen that the brush head 5 is designed as a plastic tongue, that the brush base 6 is made of an elastic plastic and that the brush head 5, the brush base 6 and the predetermined bending point 7 are integrally formed with each other. Form

this brush element 4 is somewhat different from the shape of the previously explained brush elements 4, in order to ensure that the predetermined bending point 7 really lies in the area of the cross-sectional constriction 9, so that the alternating bending stresses only really or essentially occur here.

Claims (10)

1. Brush for a brush attachment of a vacuum cleaner, with a brush holder designed as a brush roller and brush elements used in receiving chambers of the brush holder, the brush elements being arranged helically on the brush holder, characterized in that each brush element (4) consists of a bow-like or sheet-like brush head (5 ) consists of highly wear-resistant material and a brush foot (6) which can be inserted into the receiving chamber (3) of the brush holder (2). 2. Brush according to claim 1, characterized in that the brush head (5) is designed as a preferably rectangular metal bracket or as a metal tongue, as a plastic bracket or as a plastic tongue. 3. Brush according to claim 1 or 2, characterized in that a predetermined bending point (7) is provided on the brush head (5), on the brush foot (6) and / or between the brush head (5) and the brush foot (6). 4. Brush according to one of claims 1 to 3, characterized in that the brush base (6) consists of an elastic plastic and preferably to form the predetermined bending point (7) in a region outside the receiving chamber (3) has a cross-sectional constriction (9) . 5. Brush according to claim 4, characterized in that the brush head (5) is embedded on one side in the brush base (6). 6. Brush according to claim 4, characterized in that the brush head (5), optionally the predetermined bending point (7) and the brush base (6) are integrally formed with one another. 7. Brush according to one of claims 1 to 6, characterized in that the brush head (5) and / or the brush base (6) made of an electrostatically not or practically not chargeable, tough plastic, preferably made of polyurethane, rubber, Teflon, strong Teflon-containing Plastic, etc., is or exist. 8. Brush according to one of claims 1 to 7, characterized in that a plurality of brush elements are combined in a brush part and the brush part is fastened in a helical manner on the brush holder. 9. A method for producing brush elements for a brush according to one of claims 1 to 8, characterized in that a plurality of U-shaped metal brackets or of metal tongues are strung together geometrically and are connected to one another in such a way that the metal brackets or metal tongues are provided with the brush feet at the ends and that the brushing elements are separated after the joining process. 10. A method for producing brush elements for a brush according to one of claims 5 to 8, characterized in that in each case a plurality of brush elements together, possibly combined to form a closed brush part, is produced by the injection molding process or the brush elements are extruded as an endless profile strip and that the brush elements are then cut to size and separated.

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