Abstract:
An automatic pool cleaner configured to be powered by a supplied positive pressure water flow including an improved propulsion subsystem for propelling the cleaner body through a swimming pool along a substantially random travel path. The subsystem includes a hydraulic valve actuator configured to use water pressure to switch a valve element mounted for reciprocal linear movement from a default state (e.g., redirect travel state) to an active state (e.g., forward travel state) and to then restore the valve element to the default state. The water pressure for controlling the actuator is selectively supplied by a direction controller which responds to regular periodic occurrences and/or irregularly occurring events such as the interruption of cleaner body motion.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a continuation of PCT/US2004/016937 which claims priority based on U.S. Provisional Application 60/475,093 filed on 2 Jun. 2003. This application claims priority based on the two aforecited applications. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention is directed to automatic swimming pool cleaners configured to be propelled by a positive pressure water source.  
       BACKGROUND OF THE INVENTION  
       [0003]     Automatic cleaners adapted to travel through a swimming pool for cleaning debris from the water and/or wall surface are well known in the art. Some such cleaners are configured to be powered by a water flow supplied from a positive pressure source, e.g., an electric pump. The supplied water flow typically drives a propulsion subsystem configured to propel the cleaner body along a travel path through the pool with the subsystem functioning primarily to move the cleaner body in a first direction (i.e., forward state) in the pool and to occasionally redirect the cleaner body (i.e., backup/redirect state) in a different, or second, direction. By so redirecting the cleaner body, the risk that it will get trapped behind an obstruction in the pool is minimized.  
         [0004]     U.S. Pat. No. 6,365,039 (incorporated herein by reference) describes various positive pressure cleaner embodiments which incorporate a propulsion subsystem for moving the cleaner body along its travel path. The propulsion subsystems described therein generally include a valve assembly carried by the cleaner body which, in a forward state, directs a supplied water flow along a first interior path to produce forces on the body for moving it in a first direction or, in a backup/redirect state, along a second interior path to produce forces on the body to redirect it in a second direction different from the first direction. The valve assembly embodiments described in U.S. Pat. No. 6,365,039 employ a valve actuator for controlling a valve element mounted for reciprocal linear movement between first and second positions for respectively directing the supplied water flow along either the first or second interior path. When the actuator is activated, it moves the valve element from a default position to an actuated position to open one of said interior paths. When the actuator is deactivated, a spring in the actuator restores the valve element to its default position to open the other of said interior paths.  
       SUMMARY  
       [0005]     The present invention is directed to an automatic pool cleaner configured to be powered by a supplied positive pressure water flow and more particularly to an improved propulsion subsystem for propelling the cleaner body through a swimming pool along a substantially random travel path.  
         [0006]     A propulsion subsystem in accordance with the present invention includes a valve assembly selectively operable in (1) a forward travel state or (2) a backup/redirect (or “redirect”) travel state. The valve assembly is operable in (1) said forward state to discharge a water flow or “jet”, through discharge outlet(s) in a direction to produce a forward thrust on the cleaner body and (2) operable in said backup/redirect state to discharge a water jet through discharge outlet(s) in a direction to produce a thrust to redirect the cleaner body. The valve assembly includes one or more valve elements mounted for reciprocal linear movement and at least one valve actuator for selectively moving the valve element to define one of said states.  
         [0007]     A preferred valve actuator in accordance with the invention is configured to use water pressure to switch the valve element from a default state (e.g., redirect travel state) to an active state (e.g., forward travel state) and to then restore the valve element to the default state. The use of water pressure to restore the valve element to the default state, rather than springs, enhances actuator efficiency and reliability. The water pressure for controlling the actuator is selectively supplied by a direction controller which responds to regular periodic occurrences anchor irregularly occurring events such as the interruption of cleaner body motion.  
         [0008]     A valve actuator in accordance with a preferred embodiment of the invention employs a piston mounted for reciprocal linear motion. The piston has oppositely directed first and second faces which preferably have different effective areas. Thus, when positive pressure from a water source is applied to both faces, a greater force will be produced on the larger face to force the piston in a first direction to define one state. When pressure is removed from the larger face, the pressure on the smaller face will act to force the piston in a second direction to define the default state. It should be understood that the term piston as used herein is intended to broadly include a wide variety of members configured to exhibit reciprocal linear motion, e.g., a disk, a diaphragm, etc.  
         [0009]     In a preferred two state valve in accordance with the invention, a single valve actuator linearly moves a valve element to either a first position to define an active, e.g., forward propulsion, state or a second position to define a default, e.g., redirect, propulsion state.  
         [0010]     Whereas a valve assembly capable of defining two states is sufficient for establishing forward or redirect motion, a greater number of valve states is required for a cleaner additionally intended to selectively operate both at the water surface and at the containment wall surface (where “wall surface” should be understood as referring to both bottom and side wall portions). Such operation requires that the valve assembly be able to selectively define at least the following state/mode conditions: 
        1. Backup/Redirect     2. Forward/Water Surface     3. Forward/Wall Surface        
 
         [0014]     A preferred three state valve assembly in accordance with the invention arranges three outlet ports in alignment such that two reciprocally moveable valve elements, can cooperatively define anyone of the three state/mode conditions. More particularly, in a preferred embodiment, three outlet ports (i.e., Backup/Redirect, Forward/Water Surface and Forward/Wall Surface) are physically aligned with the Backup/Redirect port being located between the Forward/Water Surface and Forward/Wall Surface ports. Each of these outlet ports is respectively coupled to a discharge outlet for discharging a water jet in a direction to produce the desired thrust. The first valve element is moveable between a first position where it opens the Forward/Water Surface port and closes the Backup/Redirect port and a second position where it closes the Forward/Water Surface port and opens the Backup/Redirect port. The second valve element is moveable between a first position where it opens the Forward/Wall Surface port and closes the Backup/Redirect port and a second position where it closes the Forward/Wall Surface port and opens the Backup/Redirect port. This configuration enables the valve assembly to be switched from either of the forward mode conditions to the redirect state by activating only a single actuator.  
         [0015]     In accordance with a further significant aspect of a preferred embodiment of the invention, the Backup/Redirect outlet port is coupled to a discharge outlet on the body oriented to discharge water jets in a direction to produce a moment acting to rotate the cleaner body to redirect its travel path. More particularly, the Backup/Redirect discharge outlet is preferably comprised of nozzles respectively mounted at the front and rear of the cleaner body. The front and rear nozzles are preferably oriented to discharge water jets having oppositely directed horizontal components for rotating the body. At least one of the nozzles is also preferably oriented to discharge a jet having a vertical component for lifting the body. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0016]      FIG. 1  corresponds to FIG. 1 of U.S. Pat. No. 6,365,039 and depicts a pool cleaner body adapted to be propelled along a travel path proximate to the wall surface and/or the water surface;  
         [0017]      FIG. 2  substantially corresponds to FIG. 2 of U.S. Pat. No. 6,365,039 and schematically depicts a side view of an exemplary pool cleaner body;  
         [0018]      FIGS. 3A, 3B ,  3 C,  3 D schematically illustrate respective top, side, front, and rear views of a pool cleaner body showing a preferred configuration of nozzles for discharging respective water flows to propel the body along a travel path at the wall surface or at the water surface;  
         [0019]      FIGS. 4A, 4B ,  4 C,  4 D schematically illustrate respective top, side, front and rear views of the pool cleaner of  FIG. 3  showing a preferred configuration of nozzles for discharging respective water flows for redirecting the body&#39;s travel path;  
         [0020]      FIG. 5  is a functional block diagram depicting water flow distribution in a propulsion subsystem in accordance with the invention showing a preferred two state valve assembly embodiment for selectively directing water flows to respective discharge outlets in the forward travel state arid the redirect travel state;  
         [0021]      FIG. 6  is a functional block diagram similar to  FIG. 5  but showing an alternative two state valve assembly embodiment;  
         [0022]      FIG. 7  is a functional block diagram similar to  FIG. 6  but showing a further alternative two state valve assembly embodiment; and  
         [0023]      FIG. 8  is a functional block diagram depicting water flow distribution in accordance with the invention and showing a preferred three state valve assembly embodiment for selectively directing water flows to respective discharge outlets for forward/water surface travel, forward/wall surface travel, and redirect travel.  
     
    
     DETAILED DESCRIPTION  
       [0024]     Attention is initially directed to  FIG. 1  which corresponds to  FIG. 1  of U.S. Pat. No. 6,365,039 whose disclosure is by reference incorporated herein.  FIG. 1  illustrates an automatic pool cleaner apparatus for cleaning a water pool  1  contained in an open vessel  2  defined by a containment wall  3  having bottom  4  and side  5  portions. Embodiments of the invention utilize a unitary structure or body  6  configured for immersion in the water pool  1  for operation proximate to the interior wall surface  8  (wall surface cleaning mode). Embodiments of the invention can also be configured to selectively rise to the water surface  7  for operation proximate thereto (water surface cleaning mode).  
         [0025]     The unitary body  6  preferably comprises an essentially rigid structure having a hydrodynamically contoured exterior surface for efficient travel through the water. Although the body  6  can be variously configured it is intended that it be relatively compact in size, preferably fitting within a two foot cube envelope.  FIG. 1  depicts a heavier-than-water body  6  which in its quiescent or rest state typically sinks to a position (represented in solid line) proximate to the bottom of the pool  1 . For operation in the water surface cleaning mode, a vertical force is produced to lift the body  6  to proximate to the water surface  7  (represented in dash line). Alternatively, body  6  can be configured to be lighter-than-water such that in its quiescent or rest state, it floats proximate to the water surface  7 . For operation in the wall surface cleaning mode, a vertical force is produced to cause the lighter-than-water body to descend to the pool bottom.  
         [0026]     In accordance with the present invention, the body  6  is configured to be propelled along a travel path through the pool  1  powered by a positive pressure water flow supplied via flexible hose  9  from an electrically driven motor and hydraulic pump assembly  10 . The assembly  10  defines a pressure side outlet  11  preferably coupled via a pressure/flow regulator  12 A and quick disconnect coupling  12 B to the flexible hose  9 . The hose  9  can be formed of multiple sections coupled in tandem by hose nuts and swivels  13 . Further, the hose can be configured with appropriately placed floats  14  and distributed weight so that a significant portion of its length normally rest on the bottom of wall surface  8 .  
         [0027]     As represented in  FIG. 1 , the body  6  generally comprises a top portion or frame  6 T and a bottom portion or chassis  6 B, spaced in a nominally vertical direction. The body also generally defines a front or nose portion  6 F and a rear or tail portion  6 R spaced in a nominally horizontal direction. The body is supported on a traction means such as wheels  15  which are mounted for engaging the wall surface  8  when operating in the wall surface cleaning mode.  
         [0028]     Attention is now directed to  FIG. 2  which substantially corresponds to FIG. 2 of U.S. Pat. No. 6,365,039 and schematically depicts a unitary cleaner body  100  having a positive pressure water supply inlet  101  and multiple water outlets which are variously used by the body  100  in its different modes and states. The particular outlets active during the forward wall surface travel state and during the backup/redirect travel state in accordance with the present invention are respectively shown in  FIGS. 3A-3D  and  FIGS. 4A-4D .  
         [0029]     With reference to  FIG. 2 , the following water outlets are depicted: 
         102 —Forward Thrust Jet; provides forward propulsion and a downward force in the wall surface cleaning mode to assist in holding the traction wheels against the wall surface  8 .      104 —Rearward (“backup”) Thrust Jet; provides backward propulsion and rotation of the body around a vertical axis when in the backup/redirect state;      106 —Forward Thrust/Lift Jet; provides thrust to lift the cleaner body to the water surface and to hold it there and propel it forwardly when operating in the water surface cleaning mode;      108 —Vacuum Jet Pump Nozzle; produces a high velocity jet to create a suction at the vacuum inlet opening  109  to pull in water and debris from the adjacent wall surface  8  in the wall surface cleaning mode;      110 —Skimmer Jets; provide a flow surface water and debris into a debris container  111  when operating in the water surface cleaning mode;      112 —Debris Retention Jets; provides a flow of water toward the mouth of the debris container  111  to keep debris from escaping when operating in the backup/redirect state;      114 —Sweep Hose; discharges a water flow through hose  115  to cause it to whip and sweep against wall surface  8 .        
 
         [0037]     Attention is now directed to  FIGS. 3A, 3B ,  3 C, and  3 D which schematically illustrate top, side, front, and rear views of a cleaner body  120  in accordance with the present invention. These figures show the water outlets used for discharging water jets during wall surface and/or water surface cleaning operation for forward propulsion. Note initially that  FIGS. 3A, 3B , and  3 D illustrate a discharge nozzle  102  oriented to discharge a water jet rearwardly during wall surface operation substantially along the longitudinal centerline of the body  120 , i.e., from rear portion  6 R to nose portion  6 F to produce a thrust on the body to propel it in a first or forward direction.  
         [0038]      FIGS. 3B and 3D  illustrate a second nozzle  106  mounted at the rear of body  120  below the nozzle  102  but also substantially aligned with the longitudinal center line of the body  120 . Note that the nozzle  106  is oriented to discharge a water jet rearwardly and downwardly to produce a vertical force for lifting the body  120  to the water surface and a forward thrust for propelling the body along the water surface. The jet discharged from nozzle  106  acts to maintain the body at the water surface while propelling it forwardly in the forward/water surface travel state.  
         [0039]     Attention is now directed to  FIGS. 4A, 4B ,  4 C, and  4 D which schematically illustrate the top, side, front, and rear views of the cleaner body  120  in accordance with the present invention showing a front backup/redirect nozzle  104  and an additional rear backup/redirect nozzle  122 . The nozzles  104  and  122  are used during the backup/redirect state to redirect the travel path of the body  120  and enable it to avoid being trapped by obstructions in the pool. More particularly, note in  FIG. 4A  that nozzle  104  mounted at the front of body  120  is oriented to discharge a water jet having a horizontal component extending to the left and that nozzle  122  mounted at the rear of body  120  is oriented to discharge a water jet having a horizontal component extending to the right. The forces attributable to these oppositely directed horizontal components discharged from spaced nozzles  104  and  122  act cooperatively to produce a turning moment around the body&#39;s center of gravity to rotate the body in a clockwise direction and enable it to resume forward travel along a redirected path. In order to facilitate rotation of the body  120  when operating in the wall surface mode with wheels  15  engaged against wall surface  8 , it is preferable that the body be lifted slightly to disengage the traction wheels  15  from the wall surface. Accordingly, it is preferable that at least one of the nozzles  104 ,  122  be oriented so that the jet discharged therefrom has a vertical component acting to lift the body and wheels  15  from the wall surface. It should also be noted in  FIG. 4A  that the nozzle  104  is oriented so that the jet discharged therefrom has a forward component to produce a force acting to cause the body to move rearwardly, i.e., backup, to facilitate the body extricating itself from behind an obstruction.  
         [0040]     Thus, it should be appreciated that when the cleaner body is operating in the backup/redirect state, represented by  FIGS. 4A-4D , water jets discharged from nozzles  104  and  124  cooperate to cause the body to backup, lift, and rotate to free the body from an obstruction and modify or redirect its travel path.  
         [0041]     Attention is now directed to  FIG. 5  which schematically depicts how positive pressure water supplied to inlet  101  from pump  10  is distributed to the various body outlets shown in  FIGS. 3 and 4 . The pump  10  is typically controlled by an optional timer  124  to periodically supply positive pressure water via supply hose  9  to inlet  101 . The supplied water is then variously distributed as shown in  FIG. 5  to the various water outlets on the body  120  depending upon the defined mode and state.  
         [0042]     More particularly, water supplied to inlet  101  is directed to a state valve assembly  130  comprised of a valve body  132  and a hydraulic actuator  134  for controlling the position of a valve element  136  mounted for reciprocal linear movement in the valve body  132 . Valve body  132  includes an inlet port  140  and first and second outlet ports  142 ,  144 . The hydraulic valve actuator  134  is configured to move the valve element  136  between a default position (shown in  FIG. 5 ) and an active position to selectively close either one of the outlet ports  142 ,  144 . In the forward travel state, valve element  136  moves to its active position to close outlet port  142  and open outlet port  144 . As a consequence, positive pressure water supplied by pump  10  to inlet port  140  is directed through outlet port  144  to forward thrust jet  102  and vacuum jet pump  108 . In the redirect state, valve element  136  moves to its default position to close outlet port  144  and open outlet port  142  to direct the supplied positive pressure flow to redirect outlets  104 ,  122 .  
         [0043]     The hydraulic valve actuator  134  is comprised of a piston  148  mounted in chamber  150  for reciprocal linear movement. The piston  148  defines oppositely directed first and second faces  152 ,  154 . The first face  152  is exposed to the positive supply pressure in valve body  132 . The second face  154  is exposed to pressure supplied from outlet  155  of direction controller  156 . The positive supply pressure flow from pump  10  is supplied to direction controller  156  which selectively either directs it to piston face  154  or vents it to the pool environment via a vent valve  158 . The vent valve  158  is opened either periodically by a timing assembly  160  and/or irregularly in response to an event, such as the cessation of body motion detected by motion sensor  162 . Thus, the timing assembly  160  and motion sensor  162  control the application of the supplied positive pressure flow from pump  10  to piston face  154  via direction controller outlet  155 .  
         [0044]     It is to be noted in  FIG. 5  that the piston faces  152  and  154  have different effective areas. That is, the piston face  154  is shown as having a larger area than that of piston face  152 . As a consequence, when the positive supply pressure is concurrently applied to both faces  152  and  154 , a greater force will be developed on face  154  to move the piston  148  and valve element  136  to the left (as viewed in  FIG. 5 ), or active position, to open valve outlet port  144  to supply positive pressure water flow to forward thrust jet  102  and vacuum jet pump  108 . On the other hand, when the timing assembly and/or motion sensor open the direction controller vent valve  158 , this will relieve the pressure on piston face  154  and enable the supply pressure on face  152  to restore the valve element  136  to the right (as viewed in  FIG. 5 ), or default position.  
         [0045]     Attention is now directed to  FIG. 6  which depicts a propulsion subsystem in accordance with the invention similar to that shown in  FIG. 5  but differing therefrom in the implementation of the hydraulic actuator and direction controller. That is, it will be recalled from  FIG. 5  that the direction controller  158  has a single outlet  155 . In contrast, the direction controller  180  of  FIG. 6  has two outlets, i.e.,  182 ,  184 . The direction controller  180  operates to selectively couple the positive pressure supplied to inlet  186  to either outlet  182  or outlet  184 . Positive pressure coupled to outlet  182  bears against a first face  188  of piston  190  to move the piston to the right (default position) as viewed in  FIG. 6 . Positive pressure coupled to outlet  184  bears against the second piston face  192  to drive the piston to the left or active position.  
         [0046]     As was explained in connection with  FIG. 5 , when operating in the redirect state, the piston is in the right or default position depicted in  FIG. 6  with valve element  136  blocking valve body outlet  144 . When controller outlet  184  provides positive pressure to piston face  192  to drive the piston to the left, then valve element  136  blocks outlet  142  and opens outlet  144  to supply a positive pressure flow to discharge outlets  102  and  108 .  
         [0047]      FIG. 7  illustrates a still further alternative arrangement of the propulsion subsystem shown in  FIG. 6 . The direction controller  200  of  FIG. 7  includes first and second outlets  202 ,  204  corresponding to the two outlets of controller  180  in  FIG. 6 . The outlets  202  and  204  respectively function to apply pressure to piston faces  206  and  208 . The faces  206  and  208  are coupled by a piston rod  210  which carries a valve element  212 . When the direction controller  200  applies a positive pressure via outlet  202  to piston face  206 , it moves the piston rod and valve element  212  to the right position shown in  FIG. 6 , closing valve outlet  144  and opening valve outlet  142  to define the redirect state. This valve position of course permits the positive pressure supply from pump  10  to flow through valve outlet  142  to the redirecting jet outlets  104 ,  122  ( FIG. 4 ). On the other hand, when controller  200  supplies positive pressure via outlet  204  to piston face  208 , valve element  212  will move to the left, or active, position thereby closing valve outlet  142  and opening valve outlet  144 . In this position, the positive pressure water supplied from pump  10  will be steered through valve outlet  144  to the nozzles  102  and  108  for operation in the forward wall surface mode.  
         [0048]     It should thus now be appreciated that the propulsion subsystems depicted in  FIGS. 5, 6 , and  7  all use a hydraulic valve actuator for operating a two state valve for directing a supplied water flow to either forward propulsion discharge outlets or redirect discharge outlets. In each of the embodiments depicted in  FIGS. 5, 6 , and  7  the actuator is hydraulically driven between its two states without requiring the use of a spring restoration force. That is, in all of the embodiments a pressure applied to one piston face drives the piston in one direction whereas a pressure applied to a second piston face drives the piston in an opposite direction to a second position.  
         [0049]     It should be understood that the propulsion subsystem embodiments depicted in  FIGS. 5, 6 , and  7  are all comprised of two state valves enabling the subsystem to be operated in either a forward propulsion state or a redirect state. In systems intended to also operate in top and bottom modes for respectively cleaning both the water surface and wall surface, it is necessary to define at least three valve states. Three separate valve states can be defined by properly controlling two two state valves (e.g., of the type shown in  FIGS. 5, 6 , and  7 ) coupled in tandem. Alternatively, and preferably, a three state valve assembly  240  as shown in  FIG. 8  can be used. More particularly, valve assembly  240  is comprised of a valve body  242  having a supply inlet  244  and three outlets  246 ,  248 , and  250 . Outlet  246  leads to jets  112  and  106  (depicted in  FIG. 2 ) which are used during the forward travel state water surface mode. Outlet  250  is coupled to vacuum jet pump outlet  108  and forward thrust outlet  102  ( FIG. 2 ) which are used in the forward travel state wall surface mode. Outlet  248  is coupled to the redirection jets  104 ,  122  depicted in  FIG. 4 .  
         [0050]     The outlets  246 ,  248 , and  250  are preferably mounted in alignment with the outlet  248  located between the outlets  246  and  250 . A first valve element  260  is mounted on piston rod  262  operated by actuator  264 . The actuator  264  is selectively driven to either of two positions by a pressure supplied by state/mode controller  266  to the actuator inlet  268 . Thus, actuator  264  is able to move valve element  260  linearly to selectively close either outlet  248  or outlet  250 .  
         [0051]     A second valve element  270  is carried by piston rod  272  operated by a second actuator  274 . The actuator  274  responds to a pressure applied to its inlet  276  by controller  266  to linearly move valve element  270  to selectively close either valve outlet  246  or valve outlet  248 .  
         [0052]      FIG. 8  illustrates the valve element  260  in its left position and the valve element  270  in its left position. This positioning opens valve outlet  250  to supply positive pressure water flow to outlets  108  and  102  for forward travel in the wall surface mode. Actuation of actuator  268  to move valve element  260  to the right closes valve outlet  250  and opens outlet  248  to supply a positive pressure to redirection jets  104  and  122 . Actuation of actuator  274  will move valve element  270  to the right to close redirection outlet  248  and open the forward travel water surface outlet  246 .  
         [0053]     Thus, when valve outlet  250  is open, the cleaner body travels forward in the wall surface mode. On the other hand, when valve outlet  246  is open, the cleaner body travels in a forward direction in the water surface mode. Regardless of which forward mode the system is operating in, if the redirection state is initiated by motion sensor  162  or timing assembly  160 , only one of the actuators has to be activated to open redirection outlet  248 .  
         [0054]     Although the present invention has been described in detail with reference to only a limited number of embodiments, those skilled in the art will readily appreciate that various modifications and alternatives can be used without departing from the spirit or intended scope of the invention as defined by the appended claims.