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[0001]    The present application claims the benefit of U.S. provisional patent application No. 60/815,273, filed Jun. 21, 2006, the entire contents of which are hereby incorporated by reference. 
     
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to an automatic pool cleaner having a flexible scrubbing panel, and, more specifically, toward an automatic pool cleaner having a flexible scrubbing panel with a planar cleaning surface spring biased against the bottom of pool. 
       BACKGROUND OF THE INVENTION 
       [0003]    Automatic pool cleaning devices are generally well known in the art for removing debris from swimming pools and reducing or eliminating the need for manual vacuuming. Many swimming pools include a water filtration system with a pump for drawing or suctioning water from the pool and circulating it through the system. The filter system may include a relatively large-pored filter basket for trapping debris such as leaves and twigs and a filter canister containing a filter media for trapping smaller particles including sand and silt. From the filter canister, the water is recirculated to the pool via one or more return lines. 
         [0004]    Such filtration systems may be operated for several hours at a time on a daily basis and, in combination with traditional chemical treatments such as chlorination or the like, help keep the pool water clean. However, such water filtration systems are not particularly effective at removing debris that settles on the bottom or sides of the pool. In the past, settled debris has typically been removed by coupling a vacuum hose to the suction side of the pool water filtration system, to a skimmer well located near the water surface at one side of the pool for example, and then manually moving a vacuum head coupled to the hose over the submerged pool surfaces to vacuum settled debris directly to the filter canister where it is collected and separated from the pool water. However, manual vacuuming of a swimming pool is a labor intensive task that takes time away from enjoying the use of a swimming pool. 
         [0005]    Many automatic pool vacuum systems have been developed over the years. Such systems may be powered by a pump pumping water to the cleaner, which systems use the venturi effect to draw dirt into the cleaner, or by the pool&#39;s skimmer system which draws water into and through the cleaner. In either case, the moving water may be used to power a turbine or similar device to convert the movement of the fluid into mechanical energy for driving the wheels and moving the cleaner in a more or less random pattern along the pool bottom. Alternately, the pool cleaner could be propelled by jetting fluid from the housing or by an electric motor. 
         [0006]      FIGS. 9 and 10  illustrate, somewhat schematically, a conventional automatic pool cleaner that includes a housing  200  having a front  202 , a rear  204  and a bottom  206 . A front wheel  208  and a pair of rear wheels  210  support housing  200  for movement along the bottom  212  of a pool. A vacuum hose  214  connects the pool cleaner to a pool skimmer (not illustrated), and suction from the pool skimmer draws dirt and debris through suction inlet  216  and passage  218  to vacuum hose  214  and into the pool&#39;s filtration system (not illustrated). A second passage  220  connects a fluid drive mechanism  222  to vacuum hose  214  so that fluid drawn through drive mechanism  222  by the pool&#39;s filtration system turns a first gear  224  connected to a second gear  226  on rear wheel  210  to move the pool cleaner along the bottom  212  of the pool. Many other types of conventional automatic pool cleaners and propulsion systems are also known. 
         [0007]    Vacuuming a pool, however, does not substantially affect algae and bacteria that can grow on pool surfaces. This is due in part to the fact that the bacteria adheres to the surfaces to tightly to be vacuumed off and partly due to the protective membrane that coats many types of bacteria and algae. To remove such material, it may be necessary to periodically manually scrub the bottom and sides of the pool, or to use high concentrations of chemicals to kill the algae. 
         [0008]    Pool cleaners having motor driven brushes, such as disclosed in U.S. Pat. No. 4,154,680 to Sommer, for example, are known and may be generally effective for algae removal. However, the use of a motor to drive a brush adds to the cost and complexity of pool cleaners. It would therefore be desirable to provide a vacuum type automatic pool cleaner that provides benefits similar to those provide by more complex automatic cleaners having scrubbing brushes without the added cost and complexity of a motor driven scrubbing system. 
       SUMMARY OF THE INVENTION 
       [0009]    These problems and others are addressed by embodiments of the present invention, a first aspect of which comprises an automatic pool cleaner that includes a housing having a bottom, an outer surface and an interior and at least two wheels connected to the housing and supporting the housing for rolling movement on a support surface with the bottom facing the support surface. A propulsion system is provided in the interior that is configured to move the pool cleaner along the support surface, and the cleaner includes a suction inlet. A scrubbing panel is connected to the housing and includes at least one flexible panel and a resilient stiffener connected to the flexible panel for biasing a planar portion of the flexible panel against the support surface when the wheels support the housing on the support surface. 
         [0010]    Another feature of the invention comprises an automatic pool cleaner having a housing with a bottom, an outer surface and an interior and at least two wheels connected to the housing and supporting the housing for rolling movement on a support surface with the bottom facing the support surface. A suction inlet is provided in the housing, and a propulsion system in located in the interior of the housing to move the pool cleaner along the support surface. An arrangement for scrubbing the support surface is also provided that is connected to the housing and that has a planar face configured to contact the support surface when the at least two wheels support the housing on the support surface. 
         [0011]    A further feature of the invention comprises an automatic pool cleaner with a housing having a bottom, an outer surface and an interior and at least two wheels connected to the housing and supporting the housing for rolling movement on a support surface with the bottom facing the support surface. A propulsion system is provided in the interior that is configured to move the pool cleaner along the support surface, and a suction inlet is also provided. A scrubbing panel is connected to the cleaner and is formed of first and second non-metallic, overlapping sheets of open non-woven fibers and a resilient stiffener mounted between the first and second sheets for biasing a first portion of the scrubbing panel against the support surface. A holder connects the scrubbing panel to the housing, and the holder has a channel portion receiving a first edge of the scrubbing panel and a portion of the resilient stiffener and a flange connected to the channel that mounts on an outer wall of the housing. The scrubbing panel is configured such that, when the wheels support the housing on the support surface, a second portion of the scrubbing panel extends across a gap between the housing and the support surface, and the first portion of the scrubbing panel overlies a portion of the support surface adjacent to the pool cleaner. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    These aspects and features of the invention and others will be better understood after a reading of the following detailed description together with the following drawings wherein: 
           [0013]      FIG. 1  is a side elevational view of an automatic pool cleaner with a scrubbing panel according to a first embodiment of the present invention; 
           [0014]      FIG. 2  is a rear elevational view of the automatic pool cleaner and scrubbing panel of  FIG. 1 ; 
           [0015]      FIG. 3  is an exploded view of the scrubbing panel of  FIG. 1  removed from the automatic pool cleaner; 
           [0016]      FIG. 4  is an end elevational view of a first alternate scrubbing panel attachable to the automatic pool cleaner of  FIG. 1 ; 
           [0017]      FIG. 5  is a top plan view of a second alternative scrubbing panel attachable to the automatic pool cleaner of  FIG. 1 ; 
           [0018]      FIG. 6  is an end elevational view of a third alternative scrubbing panel attachable to the automatic pool cleaner of  FIG. 1 ; 
           [0019]      FIG. 7  is a top plan view of a fourth alternative scrubbing panel attachable to the automatic pool cleaner of  FIG. 1 ; 
           [0020]      FIG. 8  is an end elevational view of a fifth alternative scrubbing panel attachable to the automatic pool cleaner of  FIG. 1 ; 
           [0021]      FIG. 9  is a sectional side elevational view of a conventional automatic pool cleaner; and 
           [0022]      FIG. 10  is a rear elevational view of the conventional automatic pool cleaner of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Referring now to the drawings, wherein the showings are for purposes of illustrating embodiments of the invention only and not for the purpose of limiting same,  FIG. 1  illustrates an automatic pool cleaner  10  having a housing  12  with a front  14 , a rear  16  and a bottom  18 . Cleaner  10  is supported by a front wheel  20  and a pair of rear wheels  22  for rolling movement along the bottom  24  of a swimming pool. Part of one of the rear wheels  22  is broken away in  FIG. 1  so that the scrubbing panel described hereafter can be more easily seen. A vacuum hose  26  connects to housing  12  and draws debris into housing  12  through a suction inlet  28  in bottom  18  of the pool cleaner. Housing  12  contains a conventional drive mechanism, not illustrated, for moving pool cleaner  10  along pool bottom  24  in a well-known manner. While the illustrated wheels make direct contact with pool bottom  24 , wheels driving tank-like tracks could also be used without exceeding the scope of the present invention. Cleaner  10  is adapted to travel primarily in a forward direction, the direction of housing front  14 , as illustrated by arrow  26  in  FIG. 1 . 
         [0024]    A scrubbing panel  30  is connected to rear  16  of housing  12  and dragged along pool bottom  24  as the cleaner  10  traverses a pool. Scrubbing panel  30  is formed from at least one layer of a non-metallic, non-woven, flexible fiber sheet having edges  34 . Suitable pads are sold commercially as non-abrasive scrubbing or cleaning pads, and in this embodiment, a panel approximately 6 inches by 9 inches is used. A resilient stiffening element  32  having ends  36  overlies a portion of the flexible sheet. The stiffening element  32  may have a lattice-like structure as illustrated in  FIGS. 2 and 3  or may comprise a planar sheet of material as illustrated in  FIG. 6 . PVC has been found to have acceptable properties for a stiffener. Stiffening element  32  may optionally be glued or otherwise attached directly to scrubbing panel  30  or may be held adjacent panel  30  by a holder described below. 
         [0025]    As illustrated in  FIG. 3 , a holder  40  is provided for connecting scrubbing panel  30  to housing  10 . Holder  40  comprises a channel portion  42  and a flange  44  projecting therefrom. Flange  44  may be provided with a number of openings  46  through which fasteners many be inserted to connect holder  40  to rear  16  of housing  10 , or, alternately, these openings  46  may be omitted and holder  40  can be connected to housing  10  using fasteners such as self-tapping screws (not shown). Holder  40  may be formed from any suitable material, such as PVC, that will withstand prolonged submersion in chlorinated pool water. 
         [0026]    Scrubbing panel  30  is connected to holder  40  by inserting one edge  34  of the scrubbing panel in channel portion  42  together with one end  36  of the stiffener. Fasteners may be inserted through openings  46  in opposite sides of channel portion  42  and through the scrubbing panel  30  and resilient stiffener  32  to hold the scrubbing panel  30  in place. Alternately, the dimensions of the channel portion  42  and the thickness of the scrubbing panel  30  can be selected so that panel  30  can be slid into channel  42  in a direction parallel to the direction of channel  42  while ribs (not shown) at the edges of channel portion  42  make panel  30  difficult to remove in a direction perpendicular to the channel length. 
         [0027]    With the scrubbing panel  30  secured in channel portion  42  of holder  40 , holder  40  can be attached to rear  16  of pool cleaner housing  12 . Flange  44  of holder  40  is mounted on rear  16  substantially parallel to rear  16  such that the opening of channel portion  42  faces away from housing  12  and toward the bottom  24  of the pool when the cleaner  10  is supported on the pool bottom  24 . The length of scrubbing panel  30  is greater than the distance separating housing bottom  18  from pool bottom  24 , and consequently scrubbing panel  30  must bend when cleaner  10  is placed on the bottom  24  of the pool and overlay a portion of pool bottom  24  adjacent pool cleaner  10 . The scrubbing panel  30  thus includes a first portion  50  that does not contact pool bottom  24  and a second, planar portion  52  that makes contact with pool bottom  24  over a relatively large, planar area. Resilient stiffener  32  has an end  36  in the channel  42  and is bent when cleaner  10  is placed on bottom  24 . The energy stored in bent stiffener  32  helps to hold second planer portion  52  of scrubbing panel  30  in contact with the floor  24  of the pool. 
         [0028]    As the pool cleaner  10  traverses pool bottom  24 , vacuuming up debris, scrubbing panel  30  is dragged behind the pool cleaner  10 . Algae and bacteria that grow in the pool may have protective membranes that make them difficult to kill with chemicals alone. The scrubbing action produced by the movement of scrubbing panel  30  over the pool surfaces, however, breaks these membranes and either scrapes some of the algae and bacteria off the pool surface or leaves the bacteria and algae more susceptible to the chemicals used in a pool. Beneficially, scrubbing panel  30  can provide an early warning of an algae problem that may require chemical control. This is because, if algae is present in the pool, it will tend to accumulate on scrubbing panel  30  before it become visible on pool surfaces. 
         [0029]    Scrubbing panel  30  may also loosen other material from the bottom  24  of the pool so that it can be vacuumed up by suction inlet  28  on subsequent passes of the cleaner  10 . In addition, by partially blocking water inflow to suction inlet  28  from the rear of the pool cleaner  10 , suction from the sides and front of the pool cleaner  10  will generally be increased and may thus provide improved cleaning action. Scrubbing panel  30  and holder  40  may be sold as original equipment on pool cleaners of various designs or alternately added by consumers as an after-market accessory. 
         [0030]    The scrubbing panel  30  of  FIGS. 2 and 3  includes a single layer of non-woven material overlaid by a resilient stiffener  32 .  FIG. 4  illustrates an alternative scrubbing panel  60  comprising a first layer  62  of non-woven material, a second layer  64  of non-woven material, and a resilient stiffener  66  mounted therebetween. Such an arrangement allows for the secure retention of resilient stiffener  66  and may also allow scrubbing panel  60  to be reversed after first layer  62  of material is worn so that unused second layer  64  can provide additional scrubbing. 
         [0031]      FIG. 5  illustrates a scrubbing panel  70  having multiple resilient stiffening elements  72  for providing increased force against a pool bottom when scrubbing panel  70  is connected to a pool cleaner such as cleaner  10  using a holder such as holder  40 . 
         [0032]      FIG. 6  is an end view of an alternate scrubbing panel  80  that includes a sheet-like resilient stiffening element  82  that has a surface area substantially equal to the surface area of first and second scrubbing sheets  84 . 
         [0033]      FIG. 7  illustrates an alternate scrubbing panel  90  and stiffening element  92  that are generally similar to scrubbing panel  30  of  FIGS. 2 and 3 . However, scrubbing panel  90  includes an offset portion  94  for providing scrubbing action outside the wheel base of cleaner  10  thereby allowing corners and the lower portions of pool sidewalls to be scrubbed as a cleaner  10  moves along the bottom of the pool. 
         [0034]      FIG. 8  illustrates yet another scrubbing panel  100 . Panel  100  includes a plurality of reinforcing grommets  102  having openings  104  through which fasteners (not shown) may pass to secure scrubbing g panel  100  to housing  12  of a cleaner  10  without the use of a separate holder  40 . 
         [0035]    The present invention has been described herein in terms of several illustrated preferred embodiments. Various modifications and additions to these embodiments will become apparent to those skilled in the relevant arts upon a reading of the foregoing disclosure. It is intended that all such modifications and additions comprise a part of the present invention to the extent they come within the scope of the several claims appended hereto.

Summary:
An automatic pool cleaner includes a housing having a bottom, an outer surface and an interior, at least two wheels connected to the housing and supporting the housing for rolling movement on a support surface with the bottom facing the support surface, a propulsion system in the interior configured to move the pool cleaner along the support surface, a suction inlet, and a scrubbing panel connected to the housing. The scrubbing panel includes at least one flexible panel and a resilient stiffener connected to the flexible panel that is configured to bias a planar portion of the flexible panel against the support surface when the wheels support the housing on the support surface.