Patent Publication Number: US-2005115014-A1

Title: Cleaning Tool for Floor Surfaces Having an Illumination Element for a Working Area

Description:
BACKGROUND OF THE INVENTION  
      The invention relates to a cleaning tool for floor surfaces, upholstery surfaces or the like, in particular, a vacuum cleaning tool for vacuum cleaning devices such as a vacuum cleaner. The cleaning tool is comprised of a housing having a working chamber whose bottom plate comprises a suction slot that extends transversely to the working direction of the cleaning tool and is designed for taking up dirt. The cleaning tool further comprises a forwardly facing housing end wall provided with a receptacle for an illumination element for illuminating the surface to be cleaned, wherein the illumination element is arranged behind a light-permeable cover.  
      Such a vacuum cleaning tool is disclosed in U.S. Pat. No. 5,896,618. This patent proposes to arrange a rod-shaped incandescent lamp at the housing end face of the cleaning tool for providing a sufficient illumination of the working area. The rod-shaped incandescent lamp is exposed to high mechanical loads because it is provided on the end face of the housing that is exposed to mechanical loads by impact so that the lamp filament has the tendency to break. Also, a sufficient dissipation of thermal energy must be provided which is effected by a branched-off flow portion of the sucked-in air. In this connection, it cannot be prevented that the illumination body (incandescent lamp) will become soiled.  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide a cleaning tool for floor surfaces with a working area illumination that, on the one hand, ensures a bright uniform illumination of the working area and, on the other hand, provides high mechanical load resistance.  
      In accordance with the present invention, this is achieved in that the illumination element is a cold light emitting cold light lamp.  
      The illumination element is a cold light lamp that emits cold light and therefore has only minimal heat development. In this way, it becomes possible to arrange the cold light lamp in a substantially closed housing so that soiling by means of dirt particles or dust particles entrained in the sucked-in vacuum flow is prevented. The cold light lamp is resistant to strong mechanical impacts because no filament is present. Despite of this, it provides a bright glistening light that ensures a uniform strong illumination of the working area.  
      Preferably, the cold light lamp is a cold cathode lamp that has a rod-shaped basic form and ensures, when arranged transversely to the working direction, an excellent illumination of the working area across the working width. It can also be expedient to provide the cold light lamp in the form of several ultra bright LEDs (light emitting diodes) wherein the LEDs have a luminous power of at least 2,000 mcd (millicandela), preferably more than 5,000 mcd, and have a radiation angle of 20 degrees to 30 degrees.  
      In a preferred embodiment, the cold light lamp is arranged on a printed circuit board support and the printed circuit board support together with a casing and a cover that is advantageously embodied as a lens form a module. In this way, when mounting the lamp as well as in a maintenance situation, a simply exchange of the defective cold light lamp can be realized. For this purpose, the module is secured expediently by locking (snap) elements in the receptacle and the electrical connection is provided in particular by contact elements that extend expediently through the back wall of the receptacle and contact in the housing an electrical voltage connector. In this connection, the contact elements and the voltage connector are advantageously designed as a plug connection wherein one part of the plug connection is provided at the printed circuit board support and the other part of the plug connection is arranged behind the back wall in the housing. The illumination module is therefore secured mechanically safely within the receptacle of the housing by means of the snap connection as well as by means of the plug connection.  
      According to another aspect of the invention, it is proposed for compensation of alignment errors to provide between the motor shaft of an electrical drive motor and the drive shaft of a belt drive a cardan-type connection by means of a coupling wherein the coupling is configured like a claw coupling whose coupling elements engage one another with minimal radial and/or axial play. Without great constructive expenditure, mounting tolerances as well as alignment errors can be compensated by enabling corresponding radial and/or axial play.  
      According to a further independent aspect of the invention, it is provided that brush rollers are supported at their ends by means of substantially circular disk shaped support plates in the housing wherein the bearing shaft ends of the brush roller engage the support plates and the support plates, in turn, are received in a substantially rectangular bearing receptacle of the housing. In this connection, the width of the bearing receptacle is matched approximately to the diameter of the support plate.  
      In a preferred embodiment, the bearing plate is comprised of an elastic material, preferably of a soft-elastic material, particularly rubber, so that the manufacturing and mounting tolerances can be compensated easily without this having an effect on the support action of the brush roller.  
      In order to ensure a safe securing action of the support plate in the bearing receptacle, it can be advantageous to match the bottom of the bearing receptacle to the circumferential geometry of the support plate. A simple electrical cable routing is achieved in that the vacuum connector is provided with a housing section through which an electrical connecting cable can be supplied. The connecting cable is in particular guided in the pivot axis of the vacuum connector for which purpose bearing pins of the vacuum connector are hollow, in particular, they are configured as tubular pins. The cable can thus be guided through the bearing pins directly into the housing or the motor chamber of the housing in order to be connected to a connector module. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       FIG. 1  is a perspective view onto the cleaning tool according to the invention in a configuration as a vacuum cleaning tool for a vacuum cleaner or the like.  
       FIG. 2  is a view according to  FIG. 1  with the illumination module being removed.  
       FIG. 3  is a perspective rear view of the illumination module.  
       FIG. 4  is a perspective view of the illumination module according to  FIG. 3  in a view from the front.  
       FIG. 5  is a perspective view of a printed circuit board support with illumination element.  
       FIG. 6  is a detail view of the cleaning tool according to  FIG. 1  with removed top cover and demounted drive unit.  
       FIG. 7  is a perspective view of the cleaning tool according to  FIG. 1  with removed top cover.  
       FIG. 8  is a detail view of a belt drive for driving a brush roller arranged in the cleaning tool.  
       FIG. 9  shows in a schematic illustration the belt drive according to  FIG. 8 .  
       FIG. 10  is a detail view of the bottom part with a bearing receptacle provided in the sidewall.  
       FIG. 11  is a view of an end of the brush roller with slipped-on support plate.  
       FIG. 12  is a view according to  FIG. 10  with a support plate arranged in the bearing receptacle.  
       FIG. 13  is a perspective rear view of the bottom part of the housing.  
       FIG. 14  is a perspective view of a vacuum connector socket. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The cleaning tool for floor surfaces, upholstery surfaces or the like, as illustrated in the drawings, is configured as a vacuum cleaning tool for a vacuum cleaning device such as a vacuum cleaner. It is comprised of, as shown in  FIGS. 1 and 2 , of a two-part housing  1  with a top cover  2  and a bottom part  3 .  FIGS. 6 through 8  show that a working chamber  4  is provided in the housing  1  and a brush roller  5  is arranged in the working chamber  4  and driven so as to rotate about an axis of rotation  6 . The drive action is realized by a belt drive  7  that, in the illustrated embodiment, is driven by a drive motor  8 . The drive motor  8  is part of a drive unit  9  that can be inserted as a module into the motor chamber  10  of the housing  1 . The motor chamber  10  is separated from the working chamber  4  wherein the working chamber  4  in the illustrated embodiment is connected by a vacuum connector  11  to a vacuum cleaning device. The connection between the working chamber  4  and the vacuum connector  11  is realized by a vacuum opening  12  that is provided in the partition between the motor chamber  10  and the working chamber  4 . A channel extending underneath the drive unit  9  to the vacuum connector  11  adjoins the opening  12 .  
      As illustrated in  FIGS. 10 and 12 , in the bottom plate  13  of the working chamber  4  a suction slot  14  is formed which extends transversely to the working direction  15  essentially across the entire width of the working chamber  4 . As illustrated in particular in  FIG. 7 , the width of the working chamber  4  corresponds approximately to the width of the vacuum cleaning tool or the width of its housing  1 .  
      The housing  1  of the vacuum cleaning tool glides with front rollers  16  and rear rollers  17  on the surface to be cleaned wherein the housing  1  has an end face or front wall  18  facing in the working direction  15  on which an illumination module  22  for illuminating the surface to be cleaned is arranged.  
      In the illustrated embodiment, the illumination module  22  is arranged in a receptacle  19  ( FIG. 2 ) of the housing  1  wherein the receptacle  19  is arranged above the working chamber  4  and is integrated into the housing  1  or its top cover  2 . The top cover  2  has a part-circular central section  21  that delimits the motor chamber  10  for the drive unit  9  and covers the working chamber  4  in a central area at least partially. The central section  21 , transversely to the working direction  15 , is narrower than the bottom part  3  so that the vacuum cleaning tool in a plan view is of a substantially T-shaped configuration.  
      The receptacle  19  for the illumination module  22  is essentially provided in the central section  21  and has a width that matches the width of the central section  21  transversely to the working direction  15 . The receptacle  19 , as illustrated in  FIG. 2 , has a substantially triangular cross-section whose base is open for insertion of the illumination module  22 .  
      The illumination module  22 , compare also  FIGS. 3 through 6 , is comprised of a casing  23  that has a triangular cross-sectional shape ( FIG. 3 ) matching that of the receptacle  19 . On the back wall  24  of the housing  23 , a printed circuit board support  25  ( FIG. 5 ) with an illumination element  20  is arranged. The casing  23  is closed in the forward direction by a light permeable cover  26  that is preferably designed as an optical lens. The cover  26  forms approximately the hypothenuse of the casing  23  that is approximately triangular in cross-section and has a slightly convexly curved outer side wherein the cover  26  is positioned at an angle of approximately  30  degrees up to 60 degrees, preferably approximately 45 degrees, relative to the bottom plate  13  of the bottom part  3  or relative to the surface to be cleaned. The illumination element  20 , the printed circuit board support  25 , the casing  23 , and the cover  26  together form a common illumination module  22  that can be inserted into the receptacle  19 .  
      As illustrated in  FIG. 1 , the cover  26  in the mounted state of the module  22  is positioned approximately in the plane of the central section  21  so that no edges, recesses or projections are formed. Preferably, the casing  23  is secured by locking or snap elements  27  in the receptacle  19  wherein the snap elements  27  in the illustrated embodiment are formed by locking recesses in the sidewalls of the casing  23 . Counter locking elements  28  on the walls of the receptacle  19  ensure a save securing action for the illumination module  22  in the housing  1  of the cleaning tool.  
      As illustrated in  FIG. 5 , the illumination element  20  is a cold light lamp, in particular, a cold cathode lamp  30 . The tubular illumination body  29  of the cold cathode lamp  30  extends transversely to the working direction  15  preferably essentially across the entire width of the casing  23  so that an excellent light distribution is provided. Cold cathode lamps are connectable in a simple way to the supply voltage of the electrical drive motor  8  and do not require any complex ballast. When switching on the supply voltage, a illumination is immediately provided by the cold cathode lamp. A flickering, flash-like initial illumination as it is known from neon lights does not occur. For realizing a connection to the supply voltage, appropriately selected resistors  31  can be used which, as illustrated in  FIG. 3 , can be positioned in the openings of the back wall  24  of the casing  23 .  
      It can also be expedient to provide the cold light lamp  20  in the form of several ultra-bright LEDs  32  that have a luminous power of at least 2,000 mcd, preferably more than 5,000 mcd, and have a radiation angle of advantageously approximately 20 degrees to 30 degrees. In order to ensure excellent light distribution, it is moreover provided that the cover  26  is an optical lens like a Fresnel lens. For example, the side of the lens from which the light is emitted can be provided with a plurality of curved ribs  33  that extend approximately in the working direction  15 . The curvature of the ribs  33  is selected such that their focal point distance is identical. In this way, excellent diffusion of the light source arranged behind the cover  26  is provided with uniform illumination of the working area.  
      The electrical connection of the illumination element  20  is realized preferably by contact elements  34  that project from the back wall  24  of the casing  23  and pass through appropriate slots  35  in the back wall  36  of the receptacle  19 . Behind the back wall  36  of the receptacle  19 , within the motor chamber  10  in the housing  1  an electrical voltage connector  37  ( FIG. 7 ) is provided with which the contact elements  34  interact. Preferably, the contact elements and the voltage connector  37  provide a plug connection comprised of plug  38  and socket  39  wherein one part of the plug connection, in the embodiment the plug  38 , is fastened on the printed circuit board support  25  and the other part of the plug connection, in the embodiment the socket  39 , is provided behind the back wall  36  of the receptacle  19  in the motor chamber  10  of the housing  1 .  
      In the illustrated embodiment, the plug connection, i.e., the sockets  39  of the plug connection, are provided on the drive unit  9  that comprises the motor  10  for driving the brush roller  5  arranged rotatably in the working chamber  4  as well as starter module  82  ( FIG. 13 ).  
      In an independent configuration of the invention ( FIGS. 6 through 9 ), the motor shaft  40  of the drive motor  8  is connected by a coupling  41  to the drive shaft  42  of the belt drive  7  in a torque-transmitting way. The coupling  41  is configured as a claw-type plug coupling and realizes a cardan-type connection because the coupling elements  43  and  44  engage one another with minimal radial and/or axial play. As a result of the configuration of the coupling  41 , by means of the cardan-like connection realized by the claw coupling axial tolerances as well as possibly occurring axial displacements between the motor shaft  40  and the drive shaft  42  can be compensated without constructive expenditure.  
      The drive shaft  42  is secured by means of a support disk  45  in an intermediate wall or partition  46  of the housing  1  wherein the free end of the drive shaft  42  supports a pulley  47 . An endless belt, in particular, in the form of a toothed belt  48 , is arranged on the pulley  47  and drives the pulley  49  ( FIG. 9 ) secured on the base member of the brush roller  5 .  
      In another independent aspect of the present invention, the brush roller  5  is rotatably secured at its ends  50  and  51  by means of a support plate  52 , respectively, in the bottom part  3  of the housing  1 . As illustrated in  FIG. 9 , a bearing shaft end  53  of the brush roller  5  engages the bearing opening  54  of the support plate  52 . The support plate  52  is inserted into a bearing receptacle  60 . The bearing receptacle  60  is configured in cross-section as a box that is opened toward the partition plane  70  (plane where the top cover  2  and the bottom part  3  meet) of the housing  1  and has a substantially rectangular configuration. As illustrated in  FIG. 10 , the bearing box (receptacle) is open toward the working chamber  4 , preferably completely open, so that the receptacle  60  is embodied similar to a rail into which the support plate  52  is to be inserted.  
      Advantageously, the bearing plate  52  is a circular disk-shaped plate, in particular, circular plate or circular disk, which is inserted into the receptacle  60  that is open toward the partition plane  70 . As illustrated in  FIGS. 10 and 12 , the wall of the bearing receptacle  60  is delimited by ribs  61  wherein the support plate  52  rests exclusively on the rib surfaces  62 . In the gap  63  that is located between two neighboring ribs  62 , respectively, the bearing plate  52  is exposed.  
      The bearing receptacle  60  is delimited in the working direction  15  by outer wall ribs  64  and  65  that are positioned approximately perpendicularly to the partition plane  70  and extend from the housing sidewall in the direction toward the working chamber  4 . The bearing receptacle  60  is open toward the working chamber  4  so that the bearing plate, compare  FIG. 12 , is secured between the outer ribs  64  and  65  and is supported in the axial direction toward the housing sidewall by the ribs  61 . In the direction toward the working chamber  4 , the support plate  52  is secured by the brush member of the brush roller  5 .  
      Preferably, the bottom  67  of the bearing receptacle  60  is defined by means of the bottom ribs  68  having different height and is matched to the circumferential geometry of the support plate  52  so that, as illustrated in  FIG. 12 , the support plate  52  is supported about its circumference  55  on the end faces  69  of the bottom ribs  68 .  
      Preferably, the support plate  52  is formed of an elastic material so that dimensional tolerances can be easily compensated by the elasticity of the support plate  52 . In this connection, the spacing  66  of the outer ribs  64  and  65  of the bearing receptacle  60  is sized such that it corresponds approximately to the outer diameter  56  of the circular support plate  52 . Preferably, the spacing  66  is somewhat smaller than the spacing  56  so that a clamping securing action of the support plate  52  in the bearing receptacle  60  can be obtained.  
       FIGS. 13 and 14  show the supply of electrical energy into the housing  1  of the cleaning tool. By means of an electric plug coupling  80 , an external supply cable is connected. The plug coupling  80  itself is electrically connected by means of an inner cable  81  to a starter module  82  of the drive unit  9 . The cable  81  extends outside of the tubular vacuum connector  11  in a housing section  83  that is positioned above the vacuum channel  84 . As illustrated in  FIG. 14 , the housing section  83  is provided with lateral bearing pins  85  with which the vacuum connector  11  is secured in the bearing forks  86  of the bottom part  3  of the housing  1 . The cable  81  is guided from the plug coupling  80  through the housing section  83  and the tubular bearing pins  85  within the pivot axis  87  of the vacuum connector  11  into the motor chamber  10  of the housing  1  and is connected therein to the connector/starter module  82 .  
      In the illustrated embodiment, the connector module  82  is supplemented by an electronic unit  9  which, for example, by means of an infrared light barrier  91 , determines the dirt load of the vacuum flow entering via the vacuum opening  12  and displays the dirt load value by means of corresponding diodes  92  (green, yellow, red) provided in the top cover  2  of the housing  1 .  
      While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.