Abstract:
The invention relates to a washing brush for cleaning objects, having a rotatably mounted brush head which can be driven, via a gear mechanism, by a drive wheel, which drive wheel can be subjected to the action of pressurized cleaning liquid. In order to develop the washing brush such that a high torque can be imparted to the brush head at low speed, it is proposed according to the invention that the gear mechanism comprise two internally toothed hollow wheels oriented coaxially in relation to one another, one of the hollow wheels being mounted in a rotatable manner and the other hollow wheel being fixed, and at least one externally toothed coupling element, which is in operative connection with the drive wheel and simultaneously meshes with the two hollow wheels, the two hollow wheels having different numbers of teeth.

Description:
[0001]     The present disclosure relates to the subject matter disclosed in international application number PCT/EP2004/011892 of Oct. 21, 2004 and German application number 103 51 880.0 of Oct. 29, 2003, which are incorporated herein by reference in their entirety and for all purposes. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a washing brush for cleaning objects, having a rotatably mounted brush head which can be driven, via a gear mechanism, by a drive wheel, which drive wheel can be subjected to the action of pressurized cleaning liquid.  
         [0003]     Such a washing brush is known from U.S. Pat. No. 4,461,052. It is used for cleaning an object, in particular a motor vehicle. With the aid of this washing brush, a cleaning liquid, preferably water, to which a chemical may be added in order to increase the cleaning action, can be applied to the surface which is to be cleaned and, at the same time, the surface can be mechanically scrubbed by means of the rotatable brush head. The washing brush is used as an accessory for high-pressure cleaning devices, with the aid of which the cleaning liquid can be pressurized. The pressurized cleaning liquid is fed to the washing brush and directed onto the drive wheel, so that the latter is made to rotate, it being possible for the rotary movement to be transmitted to the brush head via the gear mechanism.  
         [0004]     The abovementioned document U.S. Pat. No. 4,461,052 describes a washing brush in which use is made of a planet gear mechanism having a sun wheel driven by the drive wheel, having a rotatable, internally toothed hollow wheel connected to the brush head, and having at least one planet wheel meshing with the sun wheel and the hollow wheel. The planet gear mechanism allows the speed of the turbine wheel to be reduced, so that the speed of the brush head is lower than the speed of the drive wheel, which drive wheel is made to rotate by the pressurized cleaning liquid.  
         [0005]     It is desirable if a high torque can be imparted to the rotating brush head, so that the user can press the washing brush against the surface which is to be cleaned without there being any risk of the rotary movement of the brush head being interrupted.  
         [0006]     It is an object of the present invention to develop a washing brush of the type mentioned in the introduction such that a relatively high torque can be imparted to the brush head at low speed.  
       SUMMARY OF THE INVENTION  
       [0007]     This object is achieved according to the invention, in the case of a washing brush of the generic type, in that the gear mechanism comprises two internally toothed hollow wheels oriented coaxially in relation to one another, one of the hollow wheels being mounted in a rotatable manner and the other hollow wheel being fixed, and at least one externally toothed coupling element, which is in operative connection with the drive wheel and meshes with the two hollow wheels simultaneously, the two hollow wheels having different numbers of teeth.  
         [0008]     According to the invention, the washing brush uses a gear mechanism which has two internally teethed hollow wheels on which the at least one coupling element rolls simultaneously. A first hollow wheel is disposed in a fixed manner, and a second hollow wheel is mounted in a rotatable manner coaxially in relation to the first hollow wheel. The two hollow wheels have different numbers of teeth. Since the at least one coupling element meshes with the two hollow wheels simultaneously, this difference in the number of teeth results in the two hollow wheels moving relative to one another when the coupling element rotates. The rotatable hollow wheel thus executes a rotary movement which can be transmitted to the brush head. It has been found that large reductions in speed can thus be achieved, it being possible, at the same time, for a high torque to be transmitted to the brush head.  
         [0009]     The operative connection between the drive wheel and the coupling element may be configured in a variety of different ways. For example, the coupling element may be formed as a gearwheel which is retained in a rotationally fixed manner on the drive wheel. It is advantageous, however, if the coupling element is in operative connection with the drive wheel via an intermediate gear mechanism. It may thus be provided, for example, that the at least one coupling element is configured as a planet wheel which meshes with a sun wheel, driven by the drive wheel, and with the two hollow wheels. In the case of such an embodiment, a first reduction in speed is achieved by using the planet gear mechanism with a sun wheel and at least one planet wheel, and a further reduction in speed is achieved by using the two hollow wheels, which have different numbers of teeth.  
         [0010]     Planet gear mechanisms with a fixed hollow wheel and a rotatable hollow wheel are known to the person skilled in the art as so-called Wolfrom gears, for example from laid-open application DE 195 25 831 A1. It has been found that a washing brush with such a Wolfrom gear allows particularly effective cleaning of objects, it being possible for a user to press the washing brush against the surface which is to be cleaned without there being any risk of the rotary movement of the brush head being interrupted.  
         [0011]     At the same time, the Wolfrom gear can be used to ensure that the brush head revolves only at low speed. This has proven to be advantageous in order to achieve thorough cleaning of the object, for example of a motor vehicle. On account of the low speed which can be achieved, moreover, the situation where cleaning liquid is sprayed off laterally from the brush head is avoided.  
         [0012]     As has already been explained, the drive wheel is made to rotate by being subjected to the action of pressurized cleaning liquid. In the case of a configuration of straightforward design, it is provided here that the drive wheel is configured as a turbine wheel. If use is made of a planet gear mechanism, it is advantageous here if the turbine wheel is connected integrally to the sun wheel. It may thus be provided, for example, that the turbine wheel has a rotatably mounted turbine wheel disk which bears the sun wheel in alignment with the axis of rotation of the turbine wheel disk and has turbine blades carried on its side which is directed away from the sun wheel. These turbine blades are preferably connected integrally to the turbine wheel disk.  
         [0013]     In order to achieve particularly good synchronism, it is advantageous if the gear mechanism has at least two coupling elements in the form of two diametrically opposite planet wheels.  
         [0014]     In the case of a preferred embodiment, the fixed hollow wheel is retained on a supporting plate and the rotatable hollow wheel is retained on a cover plate, the two hollow wheels and the supporting plate and the cover plate defining a gear space which accommodates the at least one coupling element. Such a configuration allows a particularly compact construction, it being possible to achieve a high mechanical loading capability at the same time. Moreover, the situation where splash water and dirt can penetrate into the gear mechanism is thus avoided.  
         [0015]     The fixed hollow wheel is preferably connected integrally to the supporting plate. The fixed hollow wheel, in combination with the supporting plate, can form a trough-like mount into which the at least one coupling element can be inserted.  
         [0016]     Moreover, it is advantageous if the rotatable hollow wheel is connected integrally to the cover plate. The rotatable hollow wheel, in combination with the cover plate, can form a gear cover which engages over the at least one coupling element.  
         [0017]     As has already been explained, it is advantageous if the drive wheel is configured as a turbine wheel with a turbine wheel disk. In the case of a preferred embodiment, this turbine wheel disk is oriented parallel to the supporting plate and, on its side which is directed away from the supporting plate, bears the turbine blades.  
         [0018]     It is advantageous here if the turbine wheel disk engages with sliding action against the supporting plate, it being particularly advantageous if the turbine wheel disk and the supporting plate have interengaging guide elements, for example guide grooves and guide ribs. This allows the turbine wheel disk to be guided on the supporting plate, a sealing function in the manner of a labyrinth seal being achieved at the same time. It may be provided, for example, that guide grooves are formed into the supporting plate, and that guide ribs, which are connected integrally to the turbine wheel disk, penetrate into the guide grooves.  
         [0019]     In the case of a preferred embodiment, the gear mechanism has an output shaft which is oriented coaxially in relation to the two hollow wheels, engages through the sun wheel and is connected in a rotationally fixed manner both to the rotatable hollow wheel and to the brush head. The rotary movement of the rotatable hollow wheel can be transmitted to the brush head via the output shaft. A compact construction is made possible here by the output shaft being disposed coaxially in relation to the two hollow wheels.  
         [0020]     The output shaft is preferably carried on a cover plate which is connected fixedly to the rotatable hollow wheel. It is advantageous here if the hollow wheel, the cover plate and the output shaft are connected integrally to one another.  
         [0021]     A particularly high mechanical loading capability is manifested by an advantageous embodiment of the washing brush according to the invention in which the washing brush comprises a housing with a base wall which is disposed parallel to a wall of the gear mechanism and is spaced apart therefrom, the wall and the base wall axially delimiting a drive space which accommodates the drive wheel. For the purpose of delimiting the drive space radially, use may be made of an annular collar which projects axially from the wall and/or the base wall and has an opening for the introduction of the cleaning agent into the drive space. The wall of the gear mechanism may be configured, for example, as a supporting plate which bears the fixed hollow wheel.  
         [0022]     It may be provided, for example, that the drive wheel is configured as a turbine wheel with turbine blades disposed in the drive space.  
         [0023]     In the case of a preferred embodiment, the output shaft engages through the drive space and a through-passage opening of the base wall and, in its end region which projects beyond the base wall, can be connected in a releasable manner to the brush head. This allows straightforward assembly of the washing brush according to the invention, for example the brush head can be positioned axially on that end region of the output shaft which projects beyond the base wall.  
         [0024]     In order to achieve particularly effective cleaning, it is advantageous if the brush head has a brush disk on which a first and a second set of cleaning bristles are retained, the cleaning bristles of the first set being oriented parallel to the axis of rotation of the brush head and the cleaning bristles of the second set being oriented obliquely in relation to the axis of rotation of the brush head. It has been found that the mechanical cleaning action can be improved by such a configuration of the brush head.  
         [0025]     It is advantageous if the brush disk engages with sliding action against a base wall of the housing of the washing brush. It is advantageous here if the brush disk and the base wall have interengaging guide elements, for example a guide rib which penetrates into an associated guide groove. The guide rib is preferably disposed on the top side of the brush disk, the top side being directed away from the cleaning bristles, and penetrates into a guide groove formed in the underside of the base wall of the housing.  
         [0026]     The following description of a preferred embodiment of the invention provides a more detailed explanation in conjunction with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]      FIG. 1  shows a bottom view of a washing brush according to the present invention;  
         [0028]      FIG. 2  shows a side view of the washing brush;  
         [0029]      FIG. 3  shows a sectional view of the washing brush;  
         [0030]      FIG. 4  shows a sectional view of a drive device of the washing brush; and  
         [0031]      FIG. 5  shows a sectional view along line  5 - 5  in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]     The drawing illustrates, schematically, a washing brush which is designated  10  overall, can be used, for example, as an accessory for a high-pressure cleaning device and can be connected to the high-pressure hose of the high-pressure cleaning device.  
         [0033]     The washing brush  10  has a housing  12  with a base wall  13  and a hood  14 , which accommodate a drive device  16  between them. Attached laterally to the hood  14  is a supply line  18  which, at its free end, carries a coupling  19 , configured as a bayonet closure, for the releasable connection of the washing brush  10  to a spray gun (not illustrated in the drawing) which is known per se and belongs to a high-pressure cleaning device.  
         [0034]     On the underside of the base wall  13 , the underside being directed away from the hood  14 , the washing brush  10  has an exchangeable brush head  21  with a brush disk  22  and with a first set of cleaning bristles  23  and a second set of cleaning bristles  24 . The brush head  21  can be rotated about an axis of rotation  26 , and the cleaning bristles of the first set of cleaning bristles are oriented parallel to the axis of rotation  26 , while the cleaning bristles of the second set of cleaning bristles are oriented obliquely in relation to the axis of rotation  26  and are directed outwards. This can clearly be seen from  FIG. 3  in particular.  
         [0035]     The drive device  16 , which is covered over by the hood  14 , comprises a gear mechanism  28  and a drive wheel in the form of a turbine wheel  30 . The latter has a turbine wheel disk  31  which is oriented parallel to the base wall  13  of the housing  12  and from which a multiplicity of turbine blades  32 , which are connected integrally to the turbine wheel disk  31 , project in the axial direction, directed towards the base wall  13 .  
         [0036]     The turbine wheel  30  is mounted in a rotatable manner on an output shaft  34  of the gear mechanism  28 , a bottom end region  35  of this output shaft engaging through a central through-passage opening  37  of the base wall  13  and forming a polygonal stub, on which the brush disk  22  can be positioned to produce a rotationally fixed connection between the output shaft  34  and the brush disk  22 .  
         [0037]     In its top end region, which is directed away from the brush disk  22 , the output shaft  34  is connected integrally to a cover plate  39  of the gear mechanism  28 , the cover plate, on its outer periphery, bearing a hollow wheel  41  which can be rotated together with the cover plate  39  and the output shaft  34  and has, on the inside, a toothing formation with a multiplicity of teeth  42 , this formation being illustrated in  FIG. 5 .  
         [0038]     Parallel to the cover plate  39 , and spaced apart therefrom, the gear mechanism  28  comprises a supporting plate  44 , and the turbine wheel disk  31  engages with sliding action against the supporting-plate underside, which is directed away form the cover plate  39 , guide grooves  45  being formed into the supporting plate  44  on its underside, i.e. directed toward the turbine wheel disk  31 , and corresponding guide ribs  47 , which are connected integrally to the turbine wheel disk  31 , penetrating into the guide grooves  45 . The supporting plate  44  and the turbine wheel disk  31  thus form a kind of labyrinth seal for protecting the gear mechanism  28  against the ingress of liquid and dirt.  
         [0039]     On its outer periphery, the supporting plate  44  carries a fixed hollow wheel  49 , which is connected in a rotationally fixed manner to it, is disposed in axial alignment with the rotatable hollow wheel  41  and has, on the inside, a toothing formation with a multiplicity of teeth  50 . The supporting plate  44  has a central through-passage bore  52  and, in combination with the cover plate  39  and with the rotatable hollow wheel  41  and the fixed hollow wheel  49 , forms a gear housing which encloses a gear space  54 , into which a sun wheel  56 , which engages through the central through-passage bore  52  and is connected integrally to the supporting plate  44 , penetrates. Meshing with the sun wheel  56  are two coupling elements in the form of two diametrically opposite planet wheels  58 ,  60  which are disposed within the gear space  54  and are in permanent meshing connection both with the teeth  42  of the rotatable hollow wheel  41  and with the teeth  50  of the fixed hollow wheel  49 .  
         [0040]     The number of teeth  42  of the inner toothing formation of the rotatable hollow wheel  41  differs from the number of teeth  50  of the inner toothing formation of the fixed hollow wheel  49 .  
         [0041]     On its underside, which is directed away from the fixed hollow wheel  49 , the supporting plate  44  carries an annular collar  62  which is directed toward the brush head  21  and on which is integrally formed, coaxially in relation to the supply line  18 , a connector  63 , which accommodates a spray nozzle  65  which penetrates, by way of a nozzle head  66 , into an inlet opening  68  formed in the annular collar  62 . The nozzle head  66  is connected integrally to the spray nozzle  65 . The annular collar  62  and the supporting plate  44  and the brush disk  22  delimit a drive space, which is configured as a turbine space  70  and into which cleaning agent can be sprayed by means of the spray nozzle  65 , it being possible for this cleaning agent to leave the turbine space  70  via through-passage openings  72  formed in the brush disk  22  and thus to pass through between the first and the second set of cleaning bristles  23  and  24 , respectively.  
         [0042]     The cleaning-agent feed can be adjusted in a stepless manner by means of a control valve  74  disposed level with the spray nozzle  65 , it being possible to vary the size of outlet cross section on the nozzle head  66  between a minimum and a maximum. The greater the outlet cross section selected on the nozzle head  66 , the lower is the speed at which the cleaning liquid makes contact with the turbine blades  32  and, consequently, the lower is the speed of the turbine wheel  30 . The speed can thus be adjusted continuously by appropriate selection of the outlet cross section. If the washing brush  10  is used in a high-pressure cleaning device in which a chemical can be mixed with the cleaning liquid, by means of an injector, in order to increase the cleaning action, then the control valve  74  can also be used to set the quantity of chemical mixed in since, in the case of a relatively large outlet cross section on the nozzle head  66 , a relatively low pressure is established downstream of the injector. This results in a relatively large drop in pressure at the injector and this, in turn, means that a relatively large quantity of chemical is mixed in. The minimum size of the outlet cross section on the nozzle head  66  is preferably selected such that, when the outlet cross section is set to the minimum size, pressure conditions in which virtually no chemical is mixed in in the injector are established. By appropriately positioning the control valve  74 , the user can thus choose between a mode of operation in which chemical is mixed in, and a lather can thus be worked up on an object which is to be cleaned, and a mode of operation in which no chemical is mixed in, and there is therefore no lather on the object.  
         [0043]     During operation of the washing brush  10 , pressurized cleaning liquid, preferably water, can be directed onto the turbine blades  32  by means of the spray nozzle  65 , so that the rotatably mounted turbine wheel  30  and the sun wheel  56 , which is connected integrally therewith, are made to rotate. This results in the two planet wheels  58 ,  60  rolling on the teeth  42  and  50  of the rotatable hollow wheel  41  and of the fixed hollow wheel  49 , and the difference in the number of teeth of the two inner toothing formations gives rise to a relative movement between the two hollow wheels  41  and  49  which, in the case of a complete revolution of the planet wheels  58 ,  60 , corresponds to the difference in the number of teeth. The hollow wheel  49  is connected in a rotationally fixed manner to the supporting plate  44 , so the relative movement between the two hollow wheels results in a rotary movement of the rotatable hollow wheel  41  and thus also of the cover plate  39  and of the output shaft  34 , which is connected integrally thereto. Depending on the difference in the number of teeth between the inner toothing formations which is selected, the fixed hollow wheel  49  and the rotatable hollow wheel  41  can be used to achieve a very large reduction in speed of the turbine wheel  30 , it being possible, at the same time, for a very large torque to be transmitted to the output shaft  34  from the turbine wheel  30 .  
         [0044]     As has already been explained, the output shaft  34  is connected to the brush head  21  in a rotationally fixed manner, so that the brush head, correspondingly, can make the output shaft  34  rotate at low speed and with a high torque.  
         [0045]     A surface which is to be cleaned, for example the surface of a motor vehicle, can be mechanically scrubbed by means of the rotatable brush head  21 . At the same time, the surface which is to be cleaned can be subjected to the action of the cleaning liquid, which passes out of the turbine space  70  via the through-passage openings  72 . This allows effective cleaning of a surface overall, it being possible for a user to press the washing brush  10  with considerable force against the surface which is to be cleaned without there being any risk of the rotary movement of the brush head  21  being interrupted.