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FIELD OF THE INVENTION 
       [0001]    This invention relates to swimming pool cleaners and more particularly, although not necessarily exclusively, to discs and bumpers of such cleaners. 
       BACKGROUND OF THE INVENTION 
       [0002]    U.S. Pat. No. 5,465,443 to Rice, et al., illustrates and describes various discs (and other components) of automatic swimming pool cleaners (APCs). The discs of the Rice patent typically are flexible, unitary structures defining central apertures for receiving footpads of APCs. Disc flexibility is advantageous for many reasons; flexible discs may bend when vertical or angled walls are encountered, for example, and adhere better to bottom surfaces of pools when surrounding areas are evacuated. Flexible discs additionally may more easily ride over objects extending upward from the bottom surfaces of pools as the APCs traverse those surfaces. 
         [0003]    Many existing discs have upper surfaces that are mostly, if not entirely, planar. This is true for discs illustrated in the Rice patent, in which only peripheral fins extend upward from the upper surfaces. Regions of the upper surfaces adjacent the central apertures, by contrast, lack upwardly-extending protrusions. See, e.g., Rice, FIG. 6. 
         [0004]    U.S. Patent Application Publication No. 2007/0261183 of Moore, et al., depicts additional discs and other components of APCs. Unlike discs of the Rice patent, those of the Moore application are not necessarily unitary structures, but instead may be formed of multiple parts. As illustrated, the discs may comprise forward, mid-, and rear sections. Although all sections are, to substantial extent, flexible, the mid- and rear sections beneficially are more flexible than are the forward sections. As noted in the Moore application, “Enhanced rigidity of [the] forward section additionally inhibits its assuming the shape of a corner or other transition within a pool . . . and prevents [the] forward section from folding under itself when departing from vertical surfaces such as walls.” See Moore, p. 3, col. 2, ¶ 0045 (numerals omitted). In turn, the greater flexibility of the mid- and rear sections provides improved sealing of the disc to surfaces and may improve the ability of APCs to climb pool walls. See id., ¶ 0046. However, notwithstanding enhanced rigidity of the forward section, it nevertheless may, at times, fold under itself in use. 
         [0005]    Like the discs of the Rice patent, those of the Moore application have generally planar upper surfaces. This is especially true for the mid- and rear sections of the discs. It likewise is true for the forward sections of the discs, although upwardly-extending peripheral fins again are shown. 
         [0006]    U.S. Pat. No. 6,049,933 to McLaughlin shows yet other APCs having bodies to which flexible discs may be attached via footpads. Also illustrated as attached to the bodies are bumper assemblies, which often function as leading edges of the cleaners. The exemplary bumper assemblies of the McLaughlin patent may include bumpers comprising main frame and fins. Whereas the fins are normally composed of flexible material, the main frames are substantially rigid. See McLaughlin, col. 2, 11. 50-67. 
         [0007]    As depicted especially in FIG. 2 of the McLaughlin patent, no direct connection between the disc and bumper assembly exists. This is consistent with conventional designs of APCs, in which the generally planar surfaces of discs are configured intentionally to be unfettered. Indeed, past efforts of restricting (nominally vertical) movement of the generally planar surfaces have resembled the systems of U.S. Pat. No. 5,014,382 to Kallenbach, in which weight retainers separate from the discs have been used to “stop” upward movement of the discs. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides discs which, contrary to conventional approaches, may be connected directly to bumpers (or similar equipment) of APCs. Particularly—although not exclusively—useful for forward sections of discs of the Moore application, the invention allows the sections to be connected mechanically to bumpers of the cleaners. Such mechanical connections provide additional support for the forward sections, reducing possible tendency of the sections to fold in use. 
         [0009]    Moreover, certain preferred versions of the invention are configured to allow non-trivial upward movement of the forward sections while still preventing non-trivial movement downward that might result in folding. These results may be achieved by providing an inverted “J”-shaped hook of limited flexibility extending upward from a disc and two spaced openings in a bumper in which the hook may be received. Whereas upward movement of the disc is not materially impeded by the interaction between the hook and bumper, downward movement is. Preferably the hook is molded as part of the disc, although it instead may be connected or attached thereto. 
         [0010]    It thus is an optional, non-exclusive object of the present invention to provide novel swimming pool cleaners and components thereof. 
         [0011]    It is an additional optional, non-exclusive object of the present invention to provide discs for APCs. 
         [0012]    It is another optional, non-exclusive object of the present invention to provide discs for APCs that, in use, may be connected directly to components of the cleaners such as bumpers. 
         [0013]    It is a further optional, non-exclusive object of the present invention to provide discs for APCs having hooks extending upward from generally planar surfaces of the discs. 
         [0014]    It is, moreover, an optional, non-exclusive object of the present invention to provide discs for APCs in which the hooks are molded together with the remainders of the discs. 
         [0015]    It is also an optional, non-exclusive object of the present invention to provide discs for APCs in which the hooks resemble inverted “J”s which are received by openings of corresponding bumpers of the APCs. 
         [0016]    Other objects, features, and advantages of the present invention will be apparent to those skilled in appropriate fields with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a section of an exemplary disc of the present invention. 
           [0018]      FIG. 2  is an elevational view of the disc section of  FIG. 1 . 
           [0019]      FIG. 3  is a perspective view of an exemplary bumper component of the present invention. 
           [0020]      FIG. 4  is a perspective view of an exemplary APC of the present invention including the disc section of  FIG. 1  and the bumper component of  FIG. 3 . 
           [0021]      FIG. 5  is an elevational view of portions of the APC of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Illustrated in  FIGS. 4-5  is exemplary disc  10  of the present invention. Disc  10  may be similar to the multi-section discs described in the Moore application. Alternatively, disc  10  may comprise forward section  14  and rear section  18  as shown in  FIGS. 4-5 . Yet alternatively, disc  10  may be a unitary structure (or otherwise). 
         [0023]    Forward section  14  of disc  10  is depicted additionally in  FIGS. 1-2 . Forward section  14  may, if desired, be similar to the forward section detailed in the Moore application. In particular, forward section  14  may have an upper surface  22  that is generally planar and from which fins  26  extend upward at or adjacent outer periphery  30 . Section  14  additionally may include apertures  32 , any or all of which may be remote from the outer periphery  30 , and may define lower surface  33  and inner periphery  34 . Included in the region of inner periphery  34  may be tongues  38 , each containing openings  42  and  46 . In use, openings  42  and  46  may receive portions of a footpad (such as that of the Moore application) to connect forward section  14  directly or indirectly to body  50  of cleaner  54 . 
         [0024]    Unlike the forward sections of the discs of the Moore application, forward section  14  includes member  58 . Member  58  preferably extends upward from upper surface  22  at or adjacent inner periphery  34 , thus effecting a discontinuity in the generally planar nature of the upper surface  22 . Furthermore, member  58  preferably is molded as part of forward section  14  and therefore integral therewith. Alternatively, however, member  58  may be adhered or connected to section  14  in any appropriate manner. 
         [0025]    In versions of forward section  14  depicted in  FIGS. 1-2  and  4 - 5 , member  58  resembles a hook or an inverted letter “J.” In particular, member  58  may comprise upstanding base  62 , transition region  66 , and flange  70 . Base  62  may include gusset  74  for additional strength and support, although the presence of gusset  74  is not required. 
         [0026]    Cleaner  54 , in the form of an APC, appears in  FIGS. 4-5 . Cleaner  54  typically (but not necessarily) is a “suction-type” hydraulic APC, with outlet  78  of body  50  connected to a hose in fluid communication with a pump of a swimming pool filtration system. The pump evacuates body  50 , depressing at least portions of lower surface  33  of disc  10  onto a surface of the pool and drawing debris-laden water from the pool into the body  50  through inlet region  82 . At some location between inlet region  82  and the pump, the water is mechanically filtered to remove some, if not all, of the debris entrained therein. Likewise at a location between inlet region  82  and the pump, a valve will be positioned and operated so as periodically to interrupt the flow of water. The periodic flow interruption produces a water-hammer effect, causing cleaner  54  to move about the pool. 
         [0027]    Body  50  may include, among other things, bumper  86 . Because cleaner  54  frequently moves in the direction of arrow A in  FIG. 5 , bumper  86  usually forms the leading edge of body  50 . Bumper  86  thus at times may function as a wear surface of body  50  or operate to deflect cleaner  54  into a different direction of movement upon encountering, for example, an obstacle within a pool. 
         [0028]    Beneficially included as part of bumper  86  is component  90  of  FIG. 3 . Although component  90  preferably is removably attached to the remainder of bumper  86  (so as to receive member  58  in the manner described below prior to attachment), it may instead be integrally formed therewith. In either circumstance, component  90  may define spaced first opening  94  and second opening  98 . As shown in  FIG. 3 , first opening  94  and second opening  98  preferably are separated by solid region  102 , although an opening of restricted width alternatively may provide the separation. 
         [0029]    First opening  94  may be sized so as to receive flange  70  of member  58 . Second opening  98 , by contrast, may be sized so as to receive base  62 . The length of solid region  102  may be approximately equal to the length of transition region  66 . 
         [0030]      FIGS. 4-5  depict exemplary interrelationship between member  58  and component  90 . As shown in these figures, base  62  has been received by second opening  98 . Such reception preferably is permanent whenever cleaner  54  is operating. Stated differently, base  62  preferably remains received by second operation  98  whenever cleaner  54  is in use. 
         [0031]    By contrast, flange  70  is positioned above first opening  94 , and transition region  66  is located above—and thus not in contact with—solid region  102 . Interaction between member  58  and component  90  hence itself does not inhibit upward movement (see arrow B) of forward section  14 . Indeed, in some versions of the invention, such upward movement may occur until upper surface  22  itself contacts component  90 . 
         [0032]    However, as forward section  14  moves downward (see arrow C), flange  70  moves toward first opening  94  and transition region  66  moves toward solid region  102 . Further downward movement initially causes first opening  94  temporarily to receive flange  70  and thereafter causes transition region  66  to contact solid region  102 . This contact inhibits yet further downward movement of forward section  14 ; i.e. solid region  102  functions as a downward limiter or “stop” for forward section  14 . 
         [0033]    Limiting movement of forward section  14  in this manner allows sufficient downward movement to occur to permit depression of forward section  14  onto a to-be-cleaned surface as body  50  is evacuated yet prevents undue downward movement that might cause portions of forward section  14  to fold under the remainder of the forward section  14 . 
         [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. For example, member  58  need not necessarily be located in a forward section of a disc, but instead may be located (or additional members  58  may be located) elsewhere on the disc. Likewise, member  58  need not necessarily interact with a component of a bumper, but rather may interact with other components of cleaner  54 . Moreover, directional roots and terms (e.g. “up,” “down,” “forward,” “rear,” “above,” etc.) are used herein solely for convenience of the reader in interpreting the drawings of the application, which generally depict cleaner  54  in an upright orientation. In use cleaner  54  may be oriented otherwise as, for example, when it climbs a wall of a pool, negotiates steps within a pool, encounters certain obstacles in the pool, or travels on sloped surfaces. Finally, the contents of the Rice, McLaughlin, and Kallenbach patents and of the Moore application are incorporated herein in their entireties by this reference.

Summary:
Detailed are swimming pool cleaners and components including discs and bumpers. Discs may include upwardly-extending hooks or similar features connecting directly with the bumpers. The direct connections additionally may be configured to allow substantial (i.e. non-trivial) upward movement of the discs from their normal locations while preventing substantial downward movement of the discs that might cause the discs undesirably to fold in use.