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CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/776,984 filed on Feb. 27, 2006, the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to devices for cleaning fluid-containing vessels and more particularly, but not exclusively, to automatic cleaners for swimming pools and components of such cleaners including, but not limited to, bodies, feet, and discs. 
       BACKGROUND OF THE INVENTION 
       [0003]    Commonly-owned U.S. Pat. No. 4,642,833 to Stoltz, et al. (the “Stoltz Patent”) discloses various valve assemblies useful for automatic swimming pool cleaners. These assemblies typically include flexible, tubular diaphragms surrounded by chambers, with the diaphragms interposed in the fluid-flow paths (i.e. “in-line”) through the cleaners. In response to variation in pressure internally and externally, the diaphragms contract and expand transversely along at least part of their lengths, thereby controlling fluid flow therethrough. 
         [0004]    Commonly-owned U.S. Pat. No. 4,742,593 to Kallenbach (the “Kallenbach Patent”) discloses additional valve assemblies for use with automatic swimming pool cleaners. These assemblies, also typically tubular and of flexible material, too may be interposed in-line, within the fluid-flow paths of such cleaners. According to the Kallenbach Patent: 
         [0005]    The body [of the tubular valve] has an intermediate section between the ends that assumes a substantially collapsed condition over a segment thereof in absence of a pressure differential between the interior and exterior. 
         [0006]    The section preferably is collapsed transversely over a segment. See Kallenbach Patent, col. 1, 11. 28-32. 
         [0007]    International Publication No. WO 02/01022 of Kallenbach, et al. (the “Kallenbach Publication”), entitled “Swimming Pool Cleaner,” details another cleaner in which a valve periodically interrupts a flow of water through the body of the cleaner. Included in the cleaner are a main flow path and a by-pass passage built into the body. See Kallenbach Publication, p. 5, 11. 8-11. Also included in one version is an “annular resilient rolling diaphragm” with an edge “located in sealing engagement with the inner wall of the body.” Id., p. 6, 11. 24-26. However, a dome-shaped valve closure member, rather than the rolling diaphragm, operates to interrupt fluid flow through the main path. Additionally, neither the rolling diaphragm nor the dome-shaped member is interposed in-line in the main water path from the inlet passage of the cleaner to the outlet of the body. 
         [0008]    U.S. Pat. No. 4,351,077 to Hofmann (the “Hofmann Patent”) describes yet another cleaning apparatus in which a valve interrupts fluid flow through the cleaner body. This valve, denoted a “flapper,” oscillates so as periodically to open and close the flow passage through the body. See Hofmann Patent, col. 2., 1. 67 through col. 3, 1. 2. Opposite the flow passage within the body is a so-called “suction communication,” which is closed when the flow passage is open and opens briefly when the flow passage is closed. See id., col. 3, 11. 9-22. 
         [0009]    Each of the Stoltz, Kallenbach, and Hofmann Patents and the Kallenbach Publication discusses “suction-side” cleaners in which a pair of concentric pipes exist, the outer of the pipes being adapted for connection to a flexible hose leading (directly or indirectly) to the inlet, or “suction side,” of a pump. An annular gap between the pipes permits water to flow through the by-pass passage of the cleaner of the Kallenbach Publication toward the flexible hose. A similar gap in versions of cleaners discussed in the Stoltz and Kallenbach Patents offers “suction communication . . . through slots [in a plate] to [a] chamber” defined at least in part by the tubular members of these patents. The contents of the Kallenbach Publication, together with those of the Stoltz, Kallenbach, and Hofmann Patents, are incorporated herein in their entireties by this reference. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides alternatives to the devices addressed in these earlier efforts, particularly (but not necessarily exclusively) those involving diaphragm valves. Included among features of the present invention are an in-line valve assembly that is periodically repositioned, typically laterally (i.e. from side-to-side) relative to the surface to be cleaned, effectively changing the initial direction of the main fluid-flow path through the cleaner body. Also included as part of the invention is a sealing mechanism that seals against the to-be-cleaned surface on the side of the valve assembly opposite the one toward which the valve is positioned at any given time. 
         [0011]    Additionally, the present invention may incorporate novel apron and foot structure. Unlike conventional aprons and associated footpads, which have circular cross-section, aprons of the invention may be truncated in the normally-forward direction of travel and extend principally transversely beneath the cleaner body. These aprons thus may be wider than they are long, allowing their associated cleaner bodies to approach pool corners more closely before the cleaner discs lose suction with the pool floors. Bearing surfaces of the feet, moreover, may constitute elongated strips of material placed parallel to the normally-forward direction of travel of the cleaners, reducing the likelihood of their engaging obstructions in the pools. 
         [0012]    Discs of the present invention may lack uniform flexibility. Instead, the discs may be least flexible toward the front of the cleaner bodies, reducing the risk of the cleaners sticking in a corner of a pool. Greater flexibility may exist in other areas for improved sealing to the to-be-cleaned surface. Flexibility in the rear part of the discs additionally may improve the ability of cleaners to climb pool walls. 
         [0013]    Innovative discs also may include fins in the forward sections to facilitate movement over obstacles encountered in use. As well, “blocking” tabs may be attached to the discs or barbed, “gripper” material may be placed underneath the finned sections if appropriate. Such tabs or material, in particular, may inhibit undesired backward movement of a cleaner when its operation commences. 
         [0014]    It thus is an optional, non-exclusive object of the present invention to provide alternative automatic swimming pool cleaners and components thereof. 
         [0015]    It also is an optional, non-exclusive object of the present invention to provide in-line valve assemblies for automatic swimming pool cleaners whose position may change in use. 
         [0016]    It is a further optional, non-exclusive object of the present invention to provide repositionable valve assemblies for suction-side automatic pool cleaners. 
         [0017]    It additionally is an optional, non-exclusive object of the present invention to provide sealing mechanisms that seal against a surface on the side of the valve assembly opposite the one toward which the valve is positioned at any given time. 
         [0018]    It is, moreover, an optional, non-exclusive object of the present invention to provide aprons and feet (footpads) with non-circular cross-sections. 
         [0019]    It is yet another optional, non-exclusive object of the present invention to provide feet that are truncated in the normally-forward direction of travel of associated cleaners and extend principally transversely beneath the cleaner bodies. 
         [0020]    It is an additional optional, non-exclusive object of the present invention to provide bearing surfaces that are placed parallel to the normally-forward travel direction. 
         [0021]    It is also an optional, non-exclusive object of the present invention to provide discs with non-uniform flexibility for use with automatic swimming pool cleaners. 
         [0022]    It is a further optional, non-exclusive object of the present invention to provide “blocking” tabs attached to the disc or barbed, “gripper” material underneath sections of the disc to inhibit undesired backward movement of a cleaner when it commences operation. 
         [0023]    Other objects, features, and advantages will be apparent to those skilled in the art with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIGS. 1-4  illustrate portions of an automatic swimming pool cleaner of the present invention containing an exemplary valve assembly and sealing mechanism. 
           [0025]      FIG. 5  is a generally bird&#39;s-eye view of the automatic swimming pool cleaner of  FIGS. 1-4 . 
           [0026]      FIG. 6  illustrates aspects of an exemplary apron of the automatic swimming pool cleaner of  FIGS. 1-4 . 
           [0027]      FIG. 7  illustrates an exemplary bearing surface of a footpad of the present invention. 
           [0028]      FIG. 8  is a perspective view of the automatic swimming pool cleaner of  FIGS. 1-4  illustrating the act of transitioning from a horizontal surface to a vertical surface of movement. 
           [0029]      FIG. 9  illustrates, somewhat schematically, barbed gripping material attached to the underside of portions of a disc of the present invention. 
           [0030]      FIGS. 10-18  show aspects of an alternate automatic swimming pool cleaner of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Well depicted in  FIGS. 5 and 8  is an exemplary automatic swimming pool cleaner  10  of the present invention. Cleaner  10  is designed primary for attachment to the inlet, or suction side, of a pump of a swimming pool filtration system. Some or all aspects of the present invention are not necessarily limited to use with suction-side automatic swimming pool cleaners, however, and conceivably could be employed as part of other devices as well. 
         [0032]    Shown in  FIGS. 5 and 8  as part of cleaner  10  are body  14 , inner pipe  18 , and outer pipe  22 . Similar to those of the cleaner described in the Kallenbach patent, inner and outer pipes  18  and  22  of cleaner  10  may be concentric, with outer pipe  22  adapted to be connected to a flexible hose leading, ultimately, to the inlet of a pump. Extending from body  14  may be arm  26 , whose end  30  may contain a weight (not shown) functioning, in part, to balance a float (also not shown) typically positioned within body  14 . However any weight need not necessarily be placed within end  30 , and indeed need not necessarily be positioned at any point within arm  26 . In use, arm  26  also may function as a bumper or bearing surface in certain situations. 
         [0033]    Also illustrated in  FIGS. 5 and 8  as part of cleaner  10  are apron  34  and disc  38 . Apron  34  may be connected directly or indirectly to footpads  68 , each of which may provide a bearing surface as cleaner  10  traverses a vessel; apron  34  may also serve as an interface connecting disc  38  to body  14 . Although disc  38  too functions, to modest extent, as a bearing surface, it also operates to effect sealing of certain surfaces as body  10  is evacuated by the pump. 
         [0034]      FIGS. 1-4  detail aspects of (nominal) underside  42  of body  14 . Visible in underside  42  is inlet  46 , through which debris-laden water or other fluid may flow into cleaner  10 . In normal use, inlet  46  is adjacent a to-be-cleaned pool surface. Also illustrated in  FIGS. 1-4  within inlet  46  is inlet end  50  of valve  54 , through which the debris-laded fluid passes before travelling through inner pipe  18  to the flexible hose and, from there, to some type of filter. 
         [0035]    Valve  54  accordingly is “in-line,” in that it forms part of this main fluid-flow path through body  14 . Any suitable valving mechanism may be employed as valve  54 . Preferably, however, valve  54  is of the diaphragm type, as depicted in the Kallenbach patent or in either of co-pending U.S. patent application Ser. Nos. 10/917,587 and 10/939,579, whose contents also are incorporated herein in their entireties by this reference. 
         [0036]    Existing diaphragm-valve assemblies fix the position of the valve relative to the remainder of the main fluid-flow path during operation. Valve  54 , by contrast, is designed to move periodically, effectively cyclically reorienting a portion of the main fluid-flow path through body  14 . Consequently, rather than maintaining inlet end  50  of valve  54  generally co-linear with the main direction of travel of the cleaner  10 , valve assembly  58  of the present invention periodically repositions inlet end  50  relative to such main travel direction. Presently preferred versions of valve assembly  58  reposition inlet end  50  from side-to-side of such main travel direction, although other motions with lateral components should be substituted instead as beneficial or desired. Further, assembly  58  conceivably periodically could reposition inlet end  50  solely along the main direction of travel (i.e. with no lateral component of motion), although applicants do not currently consider this approach to be especially advantageous. 
         [0037]    Valve assembly  58  may comprise a housing  62  for valve  54  adapted to pivot within inlet  46 . Any suitable mechanism may be employed to effect such pivoting of housing  62 , as long as the mechanism permits continued fluid communication (directly or indirectly) from valve  54  to inner pipe  18 . One or more hinges  64  ( FIG. 11 ) may also be employed to facilitate the pivoting. Each hinge  64  preferably is a one-piece “living” or similar hinge made of flexible material. 
         [0038]    Pivoting of housing  62  is shown in  FIGS. 1-3 , which illustrate differing positions of housing  62  and inlet end  50  of valve  54 .  FIG. 2 , for example, depicts inlet end  50  positioned generally co-linear with the main direction of travel of cleaner  10 .  FIG. 1 , by contrast, depicts inlet end  50  positioned to one side of such main travel direction, while  FIG. 3  details inlet end  50  positioned to the other side of such main direction. In certain preferred versions of cleaner  10 , housing  62  pivots through approximately seventy degrees, thirty-five degrees to each side of the main travel direction. 
         [0039]    Generally, inlet end  50  sweeps rapidly from side to side as cleaner  10  travels in a nominal direction.  FIGS. 1-3  thus provide snapshots of varying positions of valve  54  as a function of time. Assuming, for example, that  FIG. 2  depicts a default, resting position of valve  54  and housing  62 ,  FIG. 1  might then indicate a subsequent position of valve  54 . Thereafter, valve  54  would return to the position depicted in  FIG. 2  before travelling to the position of  FIG. 3 , followed by a return to the position of  FIG. 2  and then on to the position of  FIG. 1 . This cycle of repositioning preferably continues while cleaner  10  is operational, as applicants believe it produces better cleaning results. Nevertheless, if appropriate or desired, cleaner  10  possibly could include a mechanism that could temporarily fix the position of valve  50  along the main direction of travel of cleaner  10 , as shown in  FIG. 2 . 
         [0040]    Assembly  58  additionally may comprise one or more sealing surfaces attached to housing  62 . Two such surfaces  66 A and  66 B are depicted in  FIGS. 1-3 , with the surfaces being generally parallel to and generally symmetric about the main direction of travel of cleaner  10  when valve  54  is in the position shown in  FIG. 2 . When valve  54  is in the position shown in  FIG. 1 , surface  66 B may abut and seal against the surface to be cleaned. Conversely, when valve  54  is positioned as shown in  FIG. 3 , surface  66 A may abut and seat against the surface to be cleaned. 
         [0041]    In use, valve assembly  58  functions to counteract existing tendencies of flexible hoses to steer, or otherwise influence the movement direction of, the cleaners to which they are attached. If a hose pulls an attached cleaner to the right of a nominal path, for example, housing  62  will pivot so as to point inlet end  50  of valve  54  to the left of the nominal path. Doing so provides more suction power left of the path, effectively counteracting the influence of the hose. Similarly, if the hose pulls cleaner  10  to the left of the nominal path, housing  62  will pivot so as to direct the suction power of valve  54  to the right of the path. In this manner, the position of valve  54  continually conflicts with the movement influence provided by the flexible hose, thereby lessening the effect of such influence. 
         [0042]    Illustrated in various of  FIGS. 1-8  is apron  34 , to which one or more footpads  68  may connect. Conventional aprons, which are generally annular in shape, thus have substantially equal lengths and widths. By contrast, apron  34  is substantially wider than it is long. This configuration allows body  14  to be closer to a corner or other transition of a pool before sealing against the pool surface via disc  38  is lost. Consequently, apron  34  facilitates cleaner  10  originating its climbing of vertical surfaces of pools. 
         [0043]    Underside  70  of apron  34  surrounds housing  62  and valve  54 . Underside  70  additionally may be connected to footpads  68 , each of which includes a bearing surface  74 . Preferred versions of surfaces  74  are elongated strips of serrated plastic material placed parallel to the normally-forward direction of travel of the cleaners, reducing the likelihood of their engaging obstructions in the pools. Again preferably (albeit not necessarily), two such surfaces  74  are included as part of two footpads  68  positioned symmetrically about the main travel direction of cleaner  10 . Surfaces  74  may be separate strips of material attached to underside  70  of apron  34  using screws (as shown in  FIGS. 1-3 ) or other fasteners; alternatively, they may be molded or otherwise integrally formed as part of apron  34 . Yet alternatively, footpads  68  (together with portions of disc  38 ) may be fitted into channels  76  of a channelled version of apron  34  (see  FIG. 11 ). 
         [0044]    Aspects of disc  38  are detailed principally in  FIGS. 5 and 8 . Disc  38  may be formed of moldable plastic or other material. Preferably, however, disc  38  lacks uniform flexibility. Instead, disc  38  has lesser flexibility forward of body  14  and greater flexibility elsewhere. 
         [0045]    As depicted in  FIGS. 5 and 8 , forward section  78  of disc  38  may, but need not necessarily, constitute an arc-shaped segment of material similar to that described in U.S. Pat. No. 5,421,054 to Dawson, et al., whose contents also are incorporated herein in their entirety by this reference. As initially noted therein, fins  82  may extend radially upward from and outward of a serpentine periphery  82 , with the fins  82  providing sufficient rigidity to disc  38  to enable it to ride over various objects, including many drains, lights, valves, and other nozzles, projecting from internal surfaces of pools. Enhanced rigidity of forward section  78  additionally inhibits its assuming the shape or a corner or other transition within a pool (and thereby sticking in the corner or at the transition) and prevents forward section  78  from folding under itself when departing from vertical surfaces such as walls. 
         [0046]    Connected to any, some, or all of forward section  78 , apron  34 , footpad  68 , or body  14  are mid-section  86  and rear section  90  of disc  38 . Contrasted with forward section  78 , mid-section  86  and rear section  90  are more flexible, as they rarely function as the leading edge of cleaner  10 . This greater flexibility provides improved sealing of disc  38  to the surface to be cleaned. Flexibility of rear section  90  additionally may improve the ability of cleaner  10  to climb pool walls by permitting body  14  to rotate rearward some as generally illustrated in  FIG. 8 . 
         [0047]    Because of float placement within some versions of cleaners  10 , the center of gravity of such cleaners  10  is forward of fins  82 . Consequently, when a swimming pool pump is inactive, inner and outer pipes  18  and  22  tend to rest at a low angle to the horizontal, effectively causing cleaner  10  to “lie down.” When the pump is activated, cleaner  10  may attempt to travel backward, undesirably, rather than forward. Accordingly, undersides  94  of tongues  98  from which fins  82  protrude may include barbed gripping material  102  as shown in  FIG. 9 . Such material is configured to inhibit backward movement of cleaner  10  in these circumstances, thereby encouraging desired forward movement thereof. 
         [0048]    Alternatively or additionally, one or more tabs  106  may be attached to or integrally formed with forward section  78  of disc  38 . Shown in  FIG. 10 , an exemplary tab  106  is adapted to lie flat when cleaner  10  is moving forward so as not to impede such movement. However, should cleaner  10  attempt to travel backward in use, tab  106  will contact (catch) the floor of the pool, in turn forcing forward section  78  upward. As forward section  78  moves upward, rear section  90  will be forced downward, allowing it to adhere to the pool surface temporarily and cease the backward movement. One tab  106  preferably is positioned at rear edge  110  of forward section  78  (opposite fins  82 ), although more tabs  106  may be used and positioned otherwise as needed. 
         [0049]      FIGS. 12-18 , finally, depict an exemplary connecting scheme for footpad  68 A, disc  38 A, and apron  34 A. As detailed particularly in  FIG. 12 , each footpad  68 A may comprise one or more upstanding columns  114 , each containing one or more slots  118  so as to define a head  120 . Forward section  78 A of disc  38 A may include openings designed to receive columns  114 , as shown in  FIG. 13 . Thereafter, rear section  90 A of disc  38 A may receive selected columns  114  as it is laid over forward section  78 A (see  FIG. 14 ), following which one or more mid-sections  86 A of disc  38 A may overlay rear section  90 A (see  FIG. 15 ). The assembly  122  comprising footpads  68 A and disc  38 A may then be fitted into channels  76  of apron  34  as detailed in  FIG. 16 . The results of such fitting are shown in  FIGS. 17-18 , providing a reliable connection scheme for the relevant components. 
         [0050]    The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.

Summary:
Devices for cleaning vessels, especially swimming pools, are discussed. The devices may include repositionable in-line valves, with the valves typically moving laterally (from side to side) and changing the initial direction of the main fluid-flow path through the valves and corresponding cleaner bodies. Asymmetric feet may be utilized as part of the devices, whose bottom bearing surfaces may include elongated strips of material placed parallel to the normally-forward direction of travel of the devices. Discs of non-uniform flexibility also may be employed, and blocking tabs or gripping material may be used to inhibit undesired backward movement of a cleaner when its operation commences.