Components of automatic pool cleaners (APCs) are detailed. The components may include brushes configured to attach to blades of scrubbers of the APCs. The flexible brushes may rotate as their associated blades rotate and have fingers which flex so as to adduce contact between a to-be-cleaned pool or spa surface and bristles protruding outward from sides of the fingers.

FIELD OF THE INVENTION 
       [0001]    This invention relates to automatic pool cleaners (APCs) configured to move autonomously within liquid-containing bodies such as swimming pools and spas and more particularly, although not necessarily exclusively, to components of APCs that frictionally contact surfaces of the pools and spas. 
       BACKGROUND OF THE INVENTION 
       [0002]    Commonly-owned U.S. Patent Application Publication No. 2011/031461.7 of van der Meijden, et al., discloses various components of APCs. Among components illustrated in the van der Meijden application are devices referenced as “scrubbers.” As detailed in the van der Meijden application, an exemplary scrubber may include blades, a shaft, and optionally a gear.
   In use, [the] scrubber desirably rotates about [the] shaft so as to move water toward [an] inlet of [a] body of [an] automatic pool cleaner. Such rotation may be caused by interaction of [the] gear with a corresponding gear or other device typically located within [the] body.
 
See van der Meijden, pp. 1-2, ¶ 0026 (numerals omitted). The rotation and evacuation of water entering the inlet additionally produces “down force” tending to enhance traction of the APC as it moves along a surface within a pool.
   
 
         [0004]    Also described in the van der Meijden application as another optional part of a scrubber is a “wear surface.” If present, the wear surface may be located centrally among the blades of the scrubber and coaxial with the shaft. At least at times in use, the wear surface may contact a surface to be cleaned. See id., p. 2, ¶ 0028. 
         [0005]    Even though the van der Meijden application contemplates frictional contact between the wear surface and surfaces of a pool or spa, additional scrubbing action may be desirable—at least at times—for cleaning purposes. Including brushes spaced from (i.e. not coaxial with) the shaft of a scrubber also may be advantageous, as may be utilizing bristles which contact a surface as the scrubber rotates about the shaft. Removably attaching the brushes to a scrubber further may be beneficial, as in such cases the brushes may be removed from the scrubber when not needed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides these types of brushes useful especially (although not necessarily exclusively) with the scrubbers and APCs of the types identified in the van der Meijden application. Brushes of the invention may clip to a hub of a scrubber so as to attach to, and detach from, the scrubber easily. The brushes also preferably flex when a scrubber rotates. 
         [0007]    At least some versions of the brushes may include fingers having bristles protruding outward on either or both of opposed sides of the fingers. Prior to rotation of the scrubbers, the fingers nominally are generally perpendicular to the surface on which the associated APC rests. As scrubbers rotate, however, the fingers flex (e.g. lay over) and become more parallel to the surface. Flexing of the fingers in this manner in turn causes bristles on one side of fingers to become more perpendicular to the surface, thus readily frictionally contacting it. 
         [0008]    Because in use scrubbers of the present invention rotate about an axis generally perpendicular to the pool surface, their brush speeds relative to the surface are faster than those of passive devices (which typically are dragged along the surface) or rollers (which typically rotate about an axis parallel to the surface and in the same direction as the wheels of the cleaner). Such rotation also requires less surface-area contact between the brushes and pool surface to scrub an equivalent width of pool surface than would a roller, whose length must span that entire width. This decreased surface-area contact of the brushes produces less resistance on the drive system of the APC than would rollers, potentially enhancing the longevity and robustness of the drive system. 
         [0009]    Brushes may be attached as desired to a scrubber. Presently preferred is that at least two brushes be used with a scrubber and positioned symmetrically about the shaft. Fewer or more than two brushes may be used in connection with any particular scrubber, however, and conceivably more than one brush may be attached in a particular location. 
         [0010]    It thus is an optional, non-exclusive object of the present invention to provide components for APCs. 
         [0011]    It also is an optional, non-exclusive object of the present invention to provide improvements to scrubbers of the type identified in the van der Meijden application. 
         [0012]    It is another optional, non-exclusive object of the present invention to provide brushes configured to contact to-be-cleaned surfaces. 
         [0013]    It is an additional optional, non-exclusive object of the present invention to provide brushes that may clip, or otherwise attach, to scrubbers so as to rotate as the blades rotate. 
         [0014]    It is, moreover, an optional, non-exclusive object of the present invention to provide brushes that include flexible fingers with bristles protruding therefrom. 
         [0015]    It is a further optional, non-exclusive object of the present invention to provide brushes whose fingers flex as their associated blades rotate, thus causing contact between their bristles and a to-be-cleaned surface of a pool or spa. 
         [0016]    It is yet another optional, non-exclusive object of the present invention to provide brushes which rotate about an axis perpendicular to the to-be-cleaned surface so as to produce faster speeds and less load on drive systems than do certain passive devices and rollers. 
         [0017]    Other objects, features, and advantages of the present invention will be apparent to those skilled in relevant fields with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIGS. 1A  is an elevational view of an exemplary scrubber similar to that of those of the van der Meijden application. 
           [0019]      FIG. 1B  is a perspective view of the scrubber of  FIG. 1A . 
           [0020]      FIGS. 2A-C  are various views of an exemplary brush configured to attach to the scrubber of  FIG. 1A . 
           [0021]      FIG. 3  is an elevational view of the scrubber of  FIG. 1A  to which two brushes of  FIGS. 2A-C  have been attached. 
           [0022]      FIG. 4  is a perspective view of the scrubber of  FIG. 1A  to which one brush of  FIGS. 2A-C  has been attached for purposes of showing its flexibility. 
           [0023]      FIG. 5  is a perspective view of an APC including two scrubbers, to each of which brushes have been attached in a manner similar to  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Depicted in  FIGS. 1A-B  is exemplary scrubber  10 . Scrubber  10 , which is generally similar to scrubbers of the van der Meijden application, may include blades  14  and shaft  18 . Also illustrated in  FIGS. 1A-B  is hub  20  interconnecting blades  14  and shaft  18 . In use, scrubber  10  desirably rotates about shaft  18  so as to move water toward an inlet  21  of a cleaner such as APC  22  (see  FIG. 5 ). When the APC  22  is upright on a bottom surface of a pool, shaft  18  will be generally perpendicular to the plane of the bottom surface and thus scrubber  10  will rotate about an axis perpendicular (or generally so) to the bottom surface. 
         [0025]    Consistent with the discussion in the van der Meijden application, blades  14  preferably are “semi-rigid” in nature, meaning that they have sufficient flexibility to accommodate passage into inlet  21  of APC  22 , without blockage, of at least some larger types of debris often found in outdoor swimming pools. The term “semi-rigid” also means that blades  14  nevertheless have sufficient rigidity to move volumes of water toward the inlet  21  of the cleaner as they rotate about shaft  18 . A presently-preferred material from which blades  14  is made remains molded thermoplastic polyurethane, although other materials may be used instead. 
         [0026]    Scrubber  10  advantageously may include six blades  14  extending radially from shaft  18 . Fewer or greater numbers of blades  14  may be employed as appropriate, however. As illustrated in  FIG. 5 , two scrubbers  10  preferably are employed as part of APC  22 , with each scrubber  10  being positioned at least partly to a side of inlet  21  of the APC  22 . Again, though, fewer or greater numbers of scrubbers  10  may be utilized, and each or any scrubber  10  may be positioned in any suitable location. 
         [0027]    As shown in  FIG. 1A , many of the six blades  14  are circumferentially spaced approximately forty-five degrees, rather than approximately sixty degrees, from adjacent blades  14 . This is because attachment assemblies  26  of hub  20  have, in effect, replaced the seventh and eighth blades. The two attachment assemblies  26  are at least partially visible in  FIG. 1A  spaced circumferentially about shaft  18  by approximately one hundred eighty degrees. Symmetrical positioning of attachment assemblies  26  about shaft  18  presently is preferred, although situations may arise in which an odd number of assemblies  26 , or asymmetrical positioning of an even number of assemblies  26 , is desired. 
         [0028]    The exemplary attachment assembly  26  of  FIG. 1A  may comprise at least one recess  30 A. In the version of scrubber  10  depicted in  FIG. 1A , recess  30 A is formed by a pair of spaced walls  34 A-B connected to hub  20 . A second recess  30 B, formed by a pair of spaced walls  38 A-B connected to hub  20 , also appears in  FIG. 1A . 
         [0029]    Shown especially in  FIGS. 2A-C  is exemplary brush  42 . Included as part of brush  42  is member  46 , which is sized and shaped to be frictionally fitted into recesses  30 A and  30 B. Concurrently, clips  50  of brush  42  frictionally slide along walls  34 A-B and  38 A-B. Manipulating brush  42  in this manner connects the brush  42  to scrubber  10  for use—as shown in  FIGS. 3-5 . Because brush  42  is likely to wear through use, it preferably may be detached from scrubber  42  (as through manual force, for example) for replacement. 
         [0030]    Also included as parts of brush  42  are brush body  54 , fingers  58 , and bristles  62 . Fingers  58  depend from body  54 , with each finger  58  comprising opposed major sides  66 A-B. Bristles  52  protrude outward from these major sides  66 A-B. Although  FIGS. 2A-5  illustrate three fingers  58  depending from each body  54 , more or fewer fingers  58  may be present instead if appropriate or desired. 
         [0031]    Fingers  58  beneficially are flexible. Accordingly, as shown in  FIG. 4 , fingers  58  may flex as blades  14  rotate about shaft  18 . Whereas major sides  66 A-B are nominally vertical when APC is upright (e.g.  FIG. 5 ) and blades  14  are not rotating, flexing of fingers  58  causes major sides  66 A-B to become more closely parallel to the surface to be cleaned. Consequently, because bristles  52  protrude outward from major sides  66 A-B, these bristles  52  become more closely perpendicular to the to-be-cleaned surface as the fingers  58  flex. Bristles  52  thus in use may contact the to-be-cleaned surface so as to “scrub” the surface and suspend bottom-dwelling debris into the water of the pool for evacuation into inlet  21  of APC  22 . Consistent with other suction-type APCs, APC  22  also may include body  70  through which the evacuated water may flow to outlet  74  and then into a hose, all under influence of a pump. 
         [0032]    Moreover, because scrubber  10  rotates about an axis perpendicular to the to-be-cleaned surface, the speed of movement of brushes  42  (and hence of bristles  52 ) relative to the surface may be faster than that of passive devices which merely are dragged along the surface. This relative speed of movement likewise may be faster than that of rollers, which typically rotate about axes parallel to the surface and in the same direction as the wheels or tracks of an associated cleaner. Rotation of scrubber  10  about the perpendicular axis also requires approximately fifty percent less surface-area contact between brushes  42  and the pool surface to scrub an equivalent width of pool surface than would a roller, whose length must span that entire width. This decreased surface-area contact of brushes  42  produces less resistance on the drive system of APC  22  than would rollers, potentially enhancing the longevity and robustness of the drive system. 
         [0033]    If scrubber  10  is configured to rotate only in one direction, bristles  52  need necessarily be present only on whichever of major sides  66 A or  66 B is the “leading” side for purpose of the rotation (as the other, “trailing” major side will flex away from the to-be-cleaned surface). It nevertheless may be advantageous to include bristles  52  on the trailing major side  66 B or  66 A of brush  42  so that, when bristles  52  on the leading side wear, brush  42  may be switched to a circumferentially opposite location on scrubber  10  so that the previously-trailing side becomes the leading side and presents unworn bristles  52  to the to-be-cleaned surface. This switch effectively can double the useful life of a brush  42 . (And of course, if scrubber  10  ever is configured to rotate both clockwise and counterclockwise, including bristles  52  on both major sides  66 A-B may be valuable.) 
         [0034]    The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. Also, although “pool” and “spa” are sometimes used separately, any reference to “pool” herein may include a spa, hot tub, or other vessel in which water is placed for swimming, bathing, therapy, or recreation. Finally, incorporated herein in their entirety by this reference are the contents of the van der Meijden application.