Patent Publication Number: US-6665900-B2

Title: Pool cleaner

Description:
This application claims the benefit of copending U.S. Provisional Application No. 60/368,668, filed Mar. 29, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to pool cleaner devices for dislodging and/or collecting debris within swimming pools and the like. More particularly, this invention relates to an improved pool cleaner of the type designed for submerged and generally random travel along the floor and side wall surfaces of a swimming pool to dislodge and collect fine sediment and other debris accumulated thereon. 
     Pool cleaner devices are generally known in the art for use in maintaining residential and commercial swimming pools in a clean and attractive condition. In this regard, swimming pools conventionally include a water filtration system including a pump for drawing or suctioning water from the pool for circulation through a filter canister having filter media therein to remove and collect water-entrained debris such as leaves and twigs as well as fine particulate including sand and silt. From the filter canister, the water is recirculated to the pool via one or more return lines. Such filtration system is normally operated for several hours on a daily basis and serves, in combination with traditional chemical treatments such as chlorination or the like, to maintain the pool water in a clean and clear sanitary state. However, the water filtration system is ineffective to filter out debris which settles onto submerged floor and side wall surfaces of the swimming pool. In the past, settled debris has typically been removed by coupling a vacuum hose to the intake or suction side of the pool water filtration system, such as by connecting the vacuum hose to a skimmer well located near the water surface at one side of the pool, 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 and is thus not typically performed by the pool owner or pool cleaning service personnel on a daily basis. 
     Automatic pool cleaner devices have been developed over the years for cleaning submerged pool surfaces, thereby substantially eliminating the need for labor intensive manual vacuuming. Such automatic pool cleaners typically comprise a relatively compact cleaner housing or head coupled to the pool water filtration system by a hose and including water-powered means for causing the cleaner to travel about within a swimming pool to dislodge and collect settled debris. In one form, the pool cleaner is connected to the return or pressure side of the filtration system for receiving positive pressure water which powers a turbine for rotatably driving cleaner wheels, and also functions to induce a vacuum by venturi action to draw settled debris into a filter bag. See, for example, U.S. Pat. Nos. 3,882,574; 4,558,479; 4,589,986; 4,734,954; and 5,863,425. In another form, the pool cleaner is coupled to the suction side of the filtration system, whereby water is drawn through the pool cleaner to operate a drive mechanism for transporting the cleaner within the pool while vacuuming settled debris to the filter canister of the pool filtration system. See, for example, U.S. Pat. Nos. 3,803,658; 4,023,227; 4,133,068; 4,208,752; 4,643,217; 4,679,867; 4,729,406; 4,761,848; 5,105,496; 5,265,297; 5,634,229; 6,094,764; and 6,112,354. 
     The present invention relates to improvements in automatic pool cleaner devices, particularly with respect to providing a simplified pool cleaner construction wherein modular hydraulic and mechanical components are arranged for quick and easy assembly, and for subsequent facilitated access for service and replacement as needed. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an improved automatic pool cleaner is provided for submerged and generally random travel over the floor and submerged side wall surfaces of a swimming pool or the like to collect debris accumulated thereon. The pool cleaner comprises a hydraulically contoured external housing or shell encasing an internal frame upon which modular cleaner components are installed. 
     In the preferred form, the pool cleaner is adapted for connection via a flexible hose to a supply of water under pressure, such as by connection to the return or pressure side of a pool water filtration system. A cleaner mast unit is mounted on the internal frame and includes a supply mast having an upper end exposed through the housing shell for connection to the supply hose. The supply mast delivers the water under pressure to a water distribution manifold, which is also mounted onto the internal frame as a modular component. The water distribution manifold couples the pressurized water flow to a turbine drive unit including a water-driven turbine and appropriate reduction gears for generating a rotary drive output used for rotatably driving a plurality of cleaner wheels. The water distribution manifold additionally provides water under pressure to a plurality of upwardly directed jet nozzles mounted within a suction mast, formed as part of the cleaner mast unit, for inducing an upward vacuum-type action for drawing debris from beneath the pool cleaner and through the suction mast into a porous filter bag mounted at an upper end thereof. The water distribution manifold additionally provides water under pressure to a rearwardly directed thrust jet, and also to a rearwardly directed sweep hose fitting adapted for connection to a flexible sweep hose trailing the pool cleaner. The water distribution manifold and sweep hose fitting desirably include cooperative means for adjustably regulating water flow rearwardly through the sweep hose. 
     The turbine drive unit includes a rotatably driven output shaft having a pair of output drive gears carried respectively at opposite ends thereof. Each of these output drive gears is coupled at the associated sides of the internal frame, but within the housing shell, to a sprocket chain which is coupled in turn with a driven gear at the inboard side of each cleaner wheel for positively driven said cleaner wheels. In the preferred form, each cleaner wheel has a relatively large diameter bearing hub which is rotatably supported at an outboard end of a stub axle, which in turn has an inboard end secured by an anchor block seated within an elongated slot formed on the internal frame of the pool cleaner. The driven gear associated with each cleaner wheel is rotatably driven by the sprocket chain, and engages and drives the relatively large diameter bearing hub by means of a splined coupling for rotatably driving the cleaner wheel. 
     The external housing shell comprises upper and lower housing shells mounted onto the internal frame to encase and substantially enclose the modular components mounted on said internal frame. Each of the upper and lower housing shells is quickly and easily removable from the internal frame for access to the internal frame and the modular components mounted thereon in the event that service or replacement is required. In addition, the upper housing shell includes a convenient carrying handle with an integrated stabilizer float at a location spaced above and rearwardly of a center of gravity for the pool cleaner, for maintaining the pool cleaner in an upright orientation during normal cleaning operation within a swimming pool. 
     Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate the invention. In such drawings: 
     FIG. 1 is a somewhat schematic perspective view illustrating an improved pool cleaner embodying the novel features of the invention and shown in operation traveling generally along a floor of a swimming pool; 
     FIG. 2 is an enlarged front perspective view of the pool cleaner of FIG. 1; 
     FIG. 3 is a partially exploded rear perspective view of the pool cleaner of FIG. 1; 
     FIG. 4 is a further enlarged perspective view showing the right and top sides of the pool cleaner of FIG. 1; 
     FIG. 5 is an exploded rear perspective view depicting assembly of a stabilizer float mounted within an upper portion of a housing for the pool cleaner; 
     FIG. 6 is a top plan view of the pool cleaner; 
     FIG. 7 is an exploded top perspective view of the pool cleaner showing an upper housing shell, forming a portion of the pool cleaner housing, in exploded relation to reveal an internal frame having drive components mounted thereon; 
     FIG. 8 is an enlarged rear perspective view illustrating the pool cleaner with the upper housing shell removed; 
     FIG. 9 is a bottom plan view of the pool cleaner; 
     FIG. 10 is an exploded bottom perspective view of the pool cleaner showing a lower housing shell, also forming a portion of the pool cleaner housing, in exploded relation to reveal the internal frame; 
     FIG. 11 is an enlarged rear perspective view showing the pool cleaner with the upper and lower housing shells removed, and further depicting a water distribution manifold in exploded relation with a rearwardly directed thrust jet and a sweep hose fitting; 
     FIG. 12 is an enlarged perspective view showing one end of the sweep hose fitting, taken generally on the line  12 — 12  of FIG. 11; 
     FIG. 13 is another enlarged perspective view showing one end of the sweep hose fitting of FIG. 12; 
     FIG. 14 is a rear perspective view illustrating the water distribution manifold and a cleaner mast unit in exploded relation with the internal frame of the pool cleaner; 
     FIG. 15 is another perspective view showing the water distribution manifold and cleaner mast unit in exploded relation; 
     FIG. 16 is an enlarged fragmented exploded perspective view of a portion of the water distribution manifold to illustrate further construction details thereof; 
     FIG. 17 is a further enlarged fragmented view of a portion of the water distribution manifold, corresponding generally with the encircled region  17  of FIG. 16; 
     FIG. 18 is a front perspective view depicting the internal frame of the pool cleaner with the water distribution manifold and mast unit removed therefrom; 
     FIG. 19 is a further exploded perspective view of the pool cleaner; 
     FIG. 20 is an exploded perspective view showing a water turbine drive unit for the pool cleaner; 
     FIG. 21 is another exploded perspective view showing the water turbine drive unit; 
     FIG. 22 is a further exploded perspective view of the water turbine drive unit; and 
     FIG. 23 is an exploded perspective view illustrating disassembly of one of a plurality of rotatable wheels from the internal frame of the pool cleaner. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in the exemplary drawings, an improved automatic swimming pool cleaner referred to generally by the reference numeral  10  is provided for dislodging and/or collecting debris and sediment from within a swimming pool  12  or the like, as viewed in FIG.  1 . The pool cleaner comprises an hydraulically contoured external housing  14  (FIGS. 2-10) encasing a hydraulically operated drive system (FIGS. 7-8 and  11 - 22 ) for rotatably driving a plurality of wheels  15 ,  16  and  17  which support the pool cleaner  10  for travel over the floor  18  and side walls  20  (FIG. 1) of the swimming pool. In addition, the pool cleaner  10  includes a hydraulic vacuum system (FIGS. 7-10, and  14 - 15 ) for drawing debris and sediment into a porous collection or filter bag  22  (FIG.  1 ). In accordance with the invention, the improved pool cleaner  10  has a modular construction with the hydraulic drive and vacuum system components mounted onto an internal frame  23  (FIGS. 7-8,  10 - 11 ,  14 , and  18 - 19 ) for easy access to the modular components by removal of the external housing  14  in the event that component service or replacement is required. 
     The automatic swimming pool cleaner  10  of the present invention constitutes an improvement upon swimming pool cleaners of the general type described in U.S. Pat. Nos. 3,822,754; 4,558,479; 4,589,986; 4,734,954; and 5,863,425, which are incorporated by reference herein. Such pool cleaners are designed for generally random travel over the floor  18  and submerged side walls  20  of the swimming pool  12  having virtually any conventional construction and configuration. More particularly, as depicted in FIG. 1 by way of example, such swimming pools  12  commonly include the pool floor  18  which may be generally horizontal or of sloping contour to define comparatively shallower and deeper regions of the pool. The pool floor  18  blends generally smoothly with the side walls  20  which extend upwardly to appropriate decking  24  or the like above the surface of water  26  filling the pool. 
     A swimming pool  12  of this general type is typically provided with a filtration system  28  depicted schematically in FIG. 1 for filtering particulate and other foreign matter from the pool water  26  to maintain the pool water in a relatively clear and sanitary state. This filtration system is normally installed at a convenient location near the swimming pool and includes a circulation pump for drawing water from the pool through one or more suction ports such as a skimmer well  29  located generally at the water surface at one side of the pool and/or a floor drain  30  located in the pool floor  18 . The pool water is drawn through these suction ports  29 ,  30  for passage through appropriate suction conduits  31  and to a filter canister which separates water-entrained particulate from the pool water. The filtered pool water is coupled from the filter canister through one or more return conduits  32  for recirculation to the pool via on or more return ports  33  typically positioned slightly below the surface of the pool water  26 . 
     The pool cleaner  10  of the present invention is hydraulically operated to travel back and forth in a generally random pattern over the pool floor  18  and to climb the side walls  20  for collecting debris and sediment and the like within the filter bag  22 , wherein this particulate matter may have settled onto these submerged pool floor and side wall surfaces. In addition, the pool cleaner  10  includes means for disturbing and dislodging settled debris and sediment for suspension thereof within the pool water  26  for ultimate flow into and filtration within the main filtration system  28 . Accordingly, the pool cleaner  10  collects debris such as leaves and twigs and the like within the filter bag  22 , wherein such debris is often not drawn into the circulation system for capture by the filtration system  28 , and further functions further to maintain fine particulate in suspension with the pool water  26  to improve the overall effectiveness of the main filtration system  28 . In addition, the pool cleaner  10  tends to circulate and distribute pool chemicals such as chlorine substantially uniformly throughout the pool water, wherein such chemicals are heavier than water and otherwise tend to settle with higher concentrations at or near the bottom of the pool. Advantageously, the pool cleaner operates automatically and substantially unattended, requiring only occasional emptying of the debris collection bag  22 . 
     The hydraulic drive and vacuum systems of the pool cleaner  10  are powered by a supply of water under pressure obtained conveniently and directly from the main filtration system  28  of the swimming pool  12 . In this regard, a cleaner supply conduit  35  is shown in FIG. 1 coupled to the pressure discharge side of the main filtration system  28  for receiving a flow of pressurized water. As is known in the art, a booster pump  34  may be installed in-line with the cleaner supply conduit  35 . The cleaner supply conduit  35  is connected to a cleaner supply fitting  36  mounted at a convenient location in a pool side wall  20 . An elongated flexible hose  37  formed from a lightweight plastic material has an upstream end connected to the supply fitting  36  and a downstream end suitably coupled to the pool cleaner  10 . The length of this flexible hose  37  is chosen to permit travel of the pool cleaner over substantially the entire submerged surface areas of the floor  18  and side walls  20 , and may include one or more swivel joints  38  along the length thereof to relieve and accommodate hose twisting without kinking that could otherwise interfere with the desired cleaner operation and movement. 
     FIGS. 2-7 show the assembled pool cleaner  10  to include the hydraulically contoured external housing  14 . Two of the cleaner wheels  15  and  16  respectively comprise front and rear wheels mounted in a spaced front-to-rear orientation at one side of the housing  14 . The third cleaner wheel  17  is shown mounted at the opposite side of the housing in a position with its rotational axis offset rearwardly with respect to the front wheel  15 , and forwardly with respect to the rear wheel  16 . The pool cleaner  10  thus has a generally triangular footprint defined by the three cleaner wheels  15 ,  16  and  17 . In addition, with this arrangement, the housing  14  may include a frontal nose configuration extending generally angularly or obliquely in a transverse and rearward direction from the front wheel  15  toward the opposite side wheel  17 . The housing  14  may also include a rearward configuration extending generally angularly in a transverse and forward direction from the rear wheel  16  toward the opposite side wheel  17 . As shown, the housing  14  may conveniently include contoured cowlings  39  at the inboard sides of the cleaner wheels to overlie and substantially conceal drive train components to be described in further detail herein. If desired, a common traction tread (not shown) can be carried about the front and rear wheels  15 ,  16  at one side of the cleaner housing  14 . 
     The external housing  14  is formed from upper and lower housing shells  40  and  42  each formed from a lightweight molded plastic or the like and adapted for quick and easy mounting onto and disassembly from the internal frame  23 . More particularly, the upper housing shell  40  is removably mounted onto the internal frame  23  by means of screws  43  (FIGS. 6 and 7) or the like, and defines the upper half of the external housing  14  including a trio of semicircular and downwardly open cut-outs  44  (FIGS. 7 and 19) to accommodate wheel mount and rotary bearing structures to be described. Similarly, the lower housing shell  42  is removably mounted onto the internal frame  23  by means of screws  45  (FIGS.  9  and  10 ), and defines the lower half of the external housing  14  also including a trio of semicircular and upwardly open cut-outs  46  (FIGS. 10 and 19) to accommodate the wheel mount and rotary bearing structures to be described. When mounted onto the internal frame  23 , the upper and lower housing shells  40  and  42  fit matingly together for substantially enclosing and encasing the internal hydraulic drive and vacuum system components of the improved pool cleaner. However, these upper and lower housing shells  40  and  42  are separately or individually removable from the internal frame  23  for convenient access to internal cleaner components, when and if required. 
     According to one aspect of the invention, the upper housing shell  40  carries a stabilizer float  48  (FIG. 5) at a relatively high and rearward position on the pool cleaner  10 . More particularly, the upper housing shell  40  includes a pair of generally parallel struts  50  extending upwardly and rearwardly from opposite sides of the cleaner housing. The upper ends of these struts  50  terminate at a location substantially above and behind a center of gravity for the assembled pool cleaner. These strut upper ends are integrally joined with a transversely extending handle  52  which, in addition to providing a convenient hand grip for manually handling and carrying the pool cleaner, defines a rearwardly open pocket  53  (FIG. 5) for receiving the float  48  formed from a buoyant material such as a closed cell foam or the like. The float  48  is seated within the handle pocket  53 , and a shell-shaped float cap  54  is mounted thereover by means of a screw  55  or the like to encase the float  48  within the handle pocket  53 . In use, when the pool cleaner  10  is placed into the pool water  26 , the stabilizer float  48  orients the pool cleaner so that it will land upon the pool floor  18  in an upright orientation with the cleaner wheels engaging the pool floor. The float additionally assists in turning the cleaner around when climbing and subsequently descending vertical pool walls, resulting in a fast and effective random cleaning pattern. 
     In accordance with one aspect of the invention, the rear side of the float cap  54  incorporates a rearwardly presented recess  57  (FIG. 3) circumscribing the hole therein for receiving the screw  55 . This recess  57  is conveniently formed in a generally rectangular shape, corresponding generally to the proportional width and height of a traditional vehicle license plate. A nameplate  59  (FIGS. 3 and 5) is provided for nested mounting as by an adhesive and/or snap-fit connection or the like into this recess  57 , in a position visible from the rear of the pool cleaner. In the preferred form, the nameplate  59  includes alphabetic and/or numerical indicia to present the appearance of a vehicle license plate, wherein this indicia may be customized as desired to suit the individual owner of the pool cleaner. For example, the nameplate  59  may carry or bear numbers, letters, or other symbols, or combinations thereof. The structure of the nameplate  59  may comprise a multi-color physical plate having the appearance of a small automobile license plate or the like bearing indicia in two or three dimensional form, or it may comprise an applique or otherwise be formed by molding or similar forming directly on or in the float cap  54  or other rearwardly facing structure on the pool cleaner. 
     FIG. 7 illustrates removal of the upper housing shell  40  from the pool cleaner internal frame  23 . Such removal of the upper housing shell  40  exposes a cleaner mast unit  56  for access. In this regard, the mast unit  56  comprises a unitary structure including an upstanding and relatively small diameter supply mast  58  for connection to the flexible supply hose  37  (FIG.  1 ), and a relatively large diameter suction mast  60  through which particulate and debris are vacuumed into the filter bag  22  (FIG.  1 ). A combined swivel joint and inlet fitting  73  (FIGS. 2-5,  7 - 8  and  11 ) can be provided at the upper end of the supply mast  58  for quick and easy coupling to the flexible hose  37 . If desired, this combined swivel joint and inlet fitting  73  may include a quick-release snap-lock mechanism suitable for rapid pushbutton disconnection or the like. 
     The supply mast  58  is formed to extend generally in parallel with and in a position behind the suction mast  60 , with an array of contoured and integrally molded support ribs  62  (shown best in FIGS. 8,  11 ,  14  and  15 ) extending between the supply and suction masts  58 ,  60  to provide a strong unitized construction. A lower end of the supply mast  58  carries a laterally elongated flange  64  (shown best in FIG. 15) adapted for quick and easy mounting by screws  65  (FIG. 14) onto the upper side of the internal frame  23 , in flow alignment with a hollow mounting collar  66  (FIGS.  14  and  18 - 19 ) formed in the internal frame  23 . A lower end of the suction mast  60  extends downwardly into a matingly sized suction bore  68  (FIG. 14) formed in the internal frame  23 , and may include outwardly radiating tabs  67  at opposite sides thereof for quick and easy mounting by screws  69  onto the upper side of the internal frame  23 . 
     The upper ends of the supply mast  58  and the suction mast  60  of the cleaner mast unit  56  are both exposed through the upper housing shell  40 , when said upper shell  40  is mounted onto the internal frame  23 . That is, this upper housing shell  40  has a centrally located and generally keyhole shaped passage  70  (FIG. 7) formed therein to define a relative large diameter forward segment through which the upper end of the suction mast  60  extends, and a comparatively smaller diameter rearward segment through which the upper end of the supply mast  58  extends. The carrying handle  52  and associated ballast float  48  are located above and behind the upper end of the suction mast  58 . Desirably, the upper housing shell  40  incorporates a contoured raised cowling segment  41  surrounding the keyhole passage  70 , and sweeping upwardly rearwardly in cooperation with the struts  50  and the handle  52  to provide a sleek aerodynamic and race car look to the overall cleaner housing  14 . The upper end of the suction mast  60  is shown to include a pair of latch ports  72  (FIGS. 14-15) formed in the laterally opposed sides thereof for quick and easy removable mounting of the filter bag  22  (FIG.  1 ), wherein the filter bag  22  may be constructed according to the filter bags shown and described in U.S. Pat. Nos. 4,589,986; 4,575,423; 4,618,420; and 5,863,425, which are incorporated by reference herein. 
     The mounting collar  66  formed in the internal frame  23  couples the water under pressure from the supply mast  58  to a water distribution manifold  74 , which is also quickly and easily mounted onto the internal frame  23  as a modular component. This water distribution manifold  74  is shown best in FIGS. 11-17 and  19 , and includes an inlet tube  76  having an upper end which fits upwardly through the mounting collar  66  into flow-coupled relation with the lower end of the supply mast  58 . A seal ring  78  is desirably provided on the inlet tube upper end to prevent water leakage at this connection interface. The inlet tube  76  is formed at an upstream end of a manifold channel  80  which is cooperatively formed by interfitting upper and lower manifold sections  82  and  84  (FIGS.  15 - 16 ), and which further defines a plurality of outlets for directing the pressurized water to the hydraulic drive and vacuum systems of the pool cleaner. As shown best in FIGS.  10  and  15 - 16 , the lower manifold section  84  includes appropriate laterally extending flanges  86  for quick and easy mounting of the assembled manifold  74  onto the underside of the internal frame  23  by means of screws  87  (FIG. 10) or the like. 
     More particularly, the interfitting manifold sections  82  and  84  cooperatively define a rearwardly open thrust chamber  88 . As shown in FIG. 11, an upper narrow and generally half-circle shaped orifice  90  is formed in an upper region of this thrust chamber  88 , and a comparatively larger outlet  92  is formed in a lower region of the thrust chamber. The upper orifice  90  is formed at an off-axis position within the base of a circular seat  94  having a size and shape for receiving the matingly shaped base end of a sweep hose fitting  96 , with an O-ring seal  89  or the like (FIG. 15) interposed between the hose fitting  96  and the base of the circular seat  94 . As viewed in FIGS. 12-13, the base end of the sweep hose fitting  96  also includes a narrow and generally half-circle shaped orifice  98  for alignment with the orifice  90 , upon appropriate rotational orientation of the sweep hose fitting  96  relative to the circular seat  94 . A thrust cap  100  is removably mounted onto the manifold unit  74  by screws  101  or the like for closing the thrust chamber  88 , and for engaging and retaining the sweep hose fitting  96  with its base end positioned within the circular seat  94 . An outer or tip end of the sweep hose fitting  96  normally carries an elongated and conventional sweep hose  102  (FIG. 1) which, in response to flow of pressurized water therethrough, whips back and forth to dislodge and suspend debris and particulate within the pool water  26 . 
     In accordance with one aspect of the invention, the sweep hose fitting  96  can be rotatably adjusted relative to the circular seat  94  to obtain full or partial alignment of the orifices  90  and  98 , and thereby regulate the water flow rate to the sweep hose  102 . A spring  103  reacts between an inboard side of the thrust cap  100  and a flange  105  on the sweep hose fitting  96  for urging an annular array of stepped detents  107  on an inboard side of the flange  105  into axial bearing engagement with a mating array of stepped detents  109  on the circular seat  94 . With this construction, manual rotational adjustment of the sweep hose fitting  96  relative to the manifold unit  74  is accompanied by a detectable clicking index action. An enlarged stop ear  111  may be provided on the fitting flange  105  for rotational movement between a pair of stop tabs  113  within the thrust chamber  88 , to define opposite end limits of rotational adjustment of the sweep hose fitting  96 . Disassembly of components, in whole or in part, is thus not required for adjusting the water flow rate through the sweep hose  102 . 
     The larger lower outlet  92  opening into the thrust chamber  88  is associated with a second circular seat  104  adapted for receiving and supporting a bulb-shaped base end  106  of a rearwardly extending thrust jet  108 . The bulb end  106  of the thrust jet is retained by the thrust cap  100  in firmly seated relation on the seat  104 , with an O-ring seal  117  or the like (FIG. 15) interposed between the seat  104  and the bulb end  106 . The thrust jet  108  projects rearwardly from the bulb end  106  through the thrust cap  100 . The thrust jet  108  provides a rearwardly directed jet of pressurized water from the pool cleaner  10 , to produce a corresponding forwardly directed reaction force which assists in overall cleaner operation. The bulb end  106  conveniently accommodates manual angular directional adjustment of this generally rearwardly directed thrust jet. 
     The inlet tube  76  of the manifold unit  74  additionally supplies the water under pressure to the manifold channel  80  formed by the upper and lower manifold sections  82  and  84  of the manifold unit. As viewed best in FIGS. 15-17, this manifold channel  80  extends forwardly from the rear thrust chamber  88 , and then splits into a generally circular configuration having a size and shape to correspond generally with the diametric size and shape of the lower end of the suction mast  60 . The manifold unit  74  is mounted by the screws  87  (FIG. 10) onto the underside of the internal frame  23  with this circular channel segment aligned generally coaxially with the bore  68  formed in the internal frame  23 , and also generally coaxially with the bottom of the suction mast  60 . The manifold sections  82 ,  84  cooperatively form a plurality of upwardly directed nozzle jets  110 , four of which are shown at approximate 90° intervals lining the interior of the suction mast  60  at the lower end thereof, for jetting water upwardly within the suction mast toward the filter bag  22  mounted at the upper end thereof. These upwardly directed water jets induce an upward vacuum-type flow of water through the suction mast  60 , for drawing accumulated particulate and debris upwardly through the hollow bore  115  of the suction mast  60  and into the filter bag mounted at the upper end thereof. In this regard, the lower housing shell  42  has a contoured suction inlet  112  opening formed therein (FIGS. 9 and 10) in alignment with the lower end of the suction mast  60 , so that the pool floor or side wall surface immediately underlying the cleaner housing  14  within the triangular zone bounded by the cleaner wheels  15 ,  16  and  17  is effectively vacuumed. 
     The manifold channel  80  includes a forward extension  80 ′ (FIG. 16) protruding from the circular channel segment for delivering water under pressure to a water-powered drive unit  114 . As viewed in FIGS. 15 and 16, this forward extension  80 ′ of the manifold channel  80  terminates in an upwardly directed drive jet  116  which extends upwardly into and through a jet port  118  (FIG. 19) formed in the internal frame  23 . This drive jet  116  couples the water under pressure to the drive unit  114  which is conveniently provided in module form for quick and easy mounting onto an upper side of the frame  23  by means of screws  119  or the like (FIG.  18 ). 
     In accordance with a further aspect of the invention, the manifold unit  74  includes means for reducing or eliminating clogging of the nozzle jets  110  or the drive jet  116  by particulate carried in the flow of water under pressure supplied to the pool cleaner. As shown best in FIGS. 16-17, this anti-clog means comprises a pair of spaced-apart ribs  121  formed in the upper manifold section  82  at the underside thereof, in general alignment with each of the upwardly directed jet nozzles formed therein. These pairs of ribs  121  are oriented generally in parallel with an inter-rib spacing having a width that is approximately equal to or slightly less than the diametric size of the associated jet nozzle. With this construction, any water-entrained particulate having a size sufficient to clog one of the jet nozzles will be prevented from passage to the jet nozzles by said pairs of ribs  121 . In the event that such particulate becomes trapped by said ribs  121 , the elongated spaced-apart rib construction provides a substantial remaining pathway for continued water flow to the associated jet nozzle. In practice, it is believed that such particulate tends to bounce off the ribs  121  and not become trapped thereby, for further particulate flow to and through the water powered drive unit  114 . Persons skilled in the art will recognize and appreciate that alternative rib geometries, such as oblong or oval rib shapes, may be used. 
     The water-powered drive unit  114  is shown in detail in FIGS. 19-22. As shown, the drive unit  114  comprises a water-driven turbine  120  supported for rotation within a compact module housing including upper and lower housing members  122  and  124  retained in assembled relation by a plurality of screws or the like. The illustrative water-driven turbine  120  comprises a closed face turbine having a generally circular backplate  126  with a plurality of radially outwardly extending turbine vanes  128  formed on one side thereof. This turbine  120  is carried by a shaft  130  which is supported on the module housing by a pair of rotary bearings  132 . Importantly, the turbine  120  is mounted within the module housing with the turbine vanes  128  positioned for rotary driving in response to water under pressure delivered by the drive jet  116  through a housing port  134  aligned with the jet port  116  in the internal frame  23 . For optimum rotational speed and torque, to achieve optimally reliable driving of the pool cleaner, the turbine vanes  128  have a conventional Pelton wheel geometry extending radially outwardly from a cylindrical hub  129  and having a cup-shaped curvature defining recessed vane pockets for receiving the water under pressure jetted through the drive jet  116 . 
     A driven gear  136  is formed on the turbine  120  at the side of the backplate  126  opposite the turbine vanes  128 . This driven gear  136  is rotatably coupled to a speed reduction gear train shown to include a reduction gear  137  supported for rotation by bearings  135  and including a relatively large diameter gear segment  138  meshed with the driven gear  136 , and a second smaller diameter gear segment  140  meshed with an output gear  142  mounted on a driven or output shaft  144  for rotation therewith. The output shaft  144  is carried by a pair of bearings  146  mounted on the drive unit housing, and has opposite ends extending outwardly from the drive unit housing with a pair of drive sprockets  148  mounted thereon. With this arrangement, the output shaft  144  and the drive sprockets  148  at the exterior of the drive unit housing are rotatably driven by the water-powered turbine  120 , but at a reduced rotational speed. The internal drive components are thus protectively encased within the drive unit housing, with the pressurized water flow delivered thereto for driving the turbine  20  effectively preventing ingress of dirt and grit into contact with the moving drive components. However, the drive sprockets  148  are conveniently located outside the drive unit housing where they are accessible for quick and easy replacement without requiring disassembly of or access to the internally mounted turbine and gear components. 
     The drive sprockets  148  at the opposite sides of the turbine drive unit  114  are respectively coupled to a pair of sprocket or ladder-type chains  150  and  152  formed preferably from a metal such as stainless steel or the like for positively driving the cleaner wheels  15 ,  16  and  17 . More particularly, as shown best in FIGS. 8 and 19, the sprocket chain  150  is wrapped over the drive sprocket  148  at one side of the drive unit  114 , and further over a driven sprocket  154  mounted at the inboard side of the cleaner wheel  17  for rotation therewith. In a similar fashion, and as shown best in FIGS. 15 and 16, the second sprocket chain  152  has a longer length and is wrapped over the opposite drive sprocket  148 , and further over a pair of similar driven sprockets  154  at the inboard sides of the two remaining cleaner wheels  15  and  16 , respectively. To obtain position and common forward-direction driving of the two cleaner wheels  15  and  16 , the sprocket chain  152  is additionally wrapped over an intermediate-mounted idler sprocket  157  (FIG. 19) rotatably supported at the side of the internal frame  23  by a suitable bearing (not shown). 
     With this construction as shown and described, the drive sprockets  148  engage and drive the two sprocket chains  150  and  152  at a common forward-drive rotational speed, for correspondingly driving the cleaner wheels to transport the pool cleaner  10  over submerged floor and side wall surfaces of the swimming pool  12 . The sprocket chains  150 ,  152  provide a positive drive arrangement with essentially no slippage or uneven driven which can otherwise occur in response to drive wear or stretching of an elastomer-based drive belt. 
     The driven sprocket  154  at the inboard side of each cleaner wheel has an internal bore  156  for press-fit reception of a bushing  158  which is in turn carried on a short stub axle  160  (FIGS.  19  and  23 ). This stub axle  160  has an inboard end anchored on an elongated anchor or axle block  162  adapted for secure and stable seated mounting by means of screws  164  or the like within a laterally open pocket or slot  166  formed in the internal frame  23 . An outboard segment of the sprocket bore  156  is internally splined, as indicated by reference numeral  168  in FIG. 19, for slide-fit and rotary drive engagement with an externally splined wheel hub  170  protruding axially inwardly from the associated cleaner wheel (FIG.  19 ). An outboard side of this splined hub  170  additionally includes an internal bore  172  for press-fit reception of an outer bushing  174  carried on an outboard end of the stub axle  160 . A snap-fit cap  176  may be fitted onto the wheel hub  170  at the outboard side thereof to enclose and protect the outer bearing  174 . Suitable resilient tires  178  may be removably carried by the wheels for improved traction engagement with submerged pool surfaces. 
     This splined drive connection between the driven sprockets  154  and the cleaner wheels  15 ,  16  and  17  beneficially provides a large drive engagement contact surface area, formed on the relatively large diameters of the internally splined sprocket bores  168  and the externally splined wheel hubs  170 . This large drive engagement area permits the components to be constructed from economical plastic, while still providing reliable and long-lived service life. In addition, the elongated axle blocks  162  may advantageously have the respective metal stub axles  160  co-molded therein to provide a simple yet high strength construction. The axle blocks  162  have mounting holes preformed therein for accurate positioning within the respective frame pockets  166 , and the frame  23  may include longitudinally elongated screw holes  165  (FIG. 23) to accommodate longitudinal position adjustment of one or more of the axle blocks  23  for appropriate tensioning of the drive chains  150 ,  152 . 
     In operation, the pool cleaner  10  responds to the supply of water under pressure via the flexible hose  37  (FIG. 1) to the supply mast  58 , to traverse submerged floor and side walls surfaces of the swimming pool for vacuuming debris and other particulate sediment upwardly through the suction mast  60  to the filter bag  22 . The water distribution manifold  74  (FIGS. 11-17) delivers the pressurized water flow in the appropriate proportions to the sweep hose fitting  96  and the thrust jet  108 , and also via the nozzle jets  110  for inducing the upward vacuum action through the suction mast  60 . In addition, the water distribution manifold  74  couples the pressurized water flow via the forward drive jet  116  for powering the turbine drive unit  114 , resulting in positive drive of the cleaner wheels  15 ,  16  and  17  by means of the sprocket chains  150  and  152 . 
     In the event that service or repair of any pool cleaner component is necessary, one or both of the housing shells  40  and  42  can be quickly and easily removed from the internal frame  23 . Such removal of the upper housing shells  40  exposes the mast unit  56  for quick and easy removal and replacement if needed. The water-powered drive unit  114  is also exposed for service and replacement of the drive sprockets  148  or the associated sprocket chains  150  or  152 . Similarly, the entire drive unit  114  can be disassembled quickly and easily from the internal frame  23 , if required, for repair or replacement. Removal of the lower housing shell  42  exposes the underside of the internal frame  23  for access to the water distribution manifold  74  for similarly quick and easy repair or replacement, as needed. 
     A variety of further modifications and improvements in and to the improved pool cleaner  10  of the present invention will be apparent to those persons skilled in the art. Accordingly, no limitation on the invention is intended by way of the foregoing description and accompanying drawings, except as set forth in the appended claims.