Abstract:
A suction-powered pool cleaning robot is provided, comprising a fluid outlet, configured for connection to a suction hose, and a fluid inlet, with a fluid path therebetween, a turbine, which may be any suitable device is configured to extract energy, such as in the form of rotational motion, from a fluid flow, at least partially disposed within the fluid path so as to extract energy from flow of fluid therethrough, and an electrical control system configured to regulate at least some of the operations of the robot, the control system comprising an electrical generator for providing power to the control system and configured to be driven by the turbine, and an electronic controller configured for the regulation.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to pool cleaning robots, and particularly to those which are powered by an externally supplied suction. 
       BACKGROUND OF THE INVENTION 
       [0002]    Suction powered pool cleaning robots are well known. In general, such robots are adapted for use for cleaning a pool while being powered by an external vacuum and filtering system. The robot is designed to traverse, e.g., the bottom and/or side surfaces of the pool when attached to a hose of the vacuum system. Water which is drawn through the hose is typically filtered and returned to the pool. Thus, a main function of the robot is to carry the hose about the pool surfaces to be cleaned. Such robots may scan along a pre-determined path based on the arrangement of mechanical elements. 
       SUMMARY OF THE INVENTION 
       [0003]    According to one aspect of the present invention, there is provided a suction-powered pool cleaning robot comprising:
       a fluid outlet, configured for connection to a suction hose, and a fluid inlet, with a fluid path therebetween;   a turbine, which may be any suitable device is configured to extract energy, such as in the form of rotational motion, from a fluid flow, at least partially disposed within the fluid path so as to extract energy from flow of fluid therethrough; and   an electrical control system configured to regulate at least some of the operations of the robot, the control system comprising an electrical generator for providing power to the control system and configured to be driven by the turbine, and an electronic controller configured for the regulation.       
 
         [0007]    By providing an electrical control system as described above, it may operate in a self-sufficient manner, i.e., generating the electricity needed for operation of the electronic controller during normal operation of the robot. 
         [0008]    The electrical control system may be housed within a sealed casing, the turbine being magnetically coupled to the electrical generator. 
         [0009]    The suction-powered pool cleaning robot may further comprise:
       a housing;   two drive wheels for providing locomotion of the robot and being disposed external to the housing on opposite sides thereof; and   a drive mechanism configured to be driven by the turbine and to rotate the drive wheels independently of one another.       
 
         [0013]    The electronic controller may be configured to perform the regulation by influencing the rotation of at least one of the drive wheels. 
         [0014]    The drive mechanism may comprise two coaxial axles, each mounted with one of the drive wheels, with at least one of the axles constitutes a reversible axle and being configured to be selectively driven between two angular directions under unidirectional rotation of the turbine. 
         [0015]    The drive mechanism may further comprise a drive gear configured to drive the reversible axle, the drive mechanism further comprising a reversing mechanism comprising:
       first and second selection gears in drive communication with the turbine such that they rotate in opposite angular directions from one other; and   a drive selection mechanism configured to selectively engage (i.e., mesh with) no more than one of the selection gears with the drive gear.       
 
         [0018]    The reversing mechanism may comprise a series of gears, including at least the selection gears, on a rocker mechanism configured to be pivoted between first and second positions; the rocker mechanism being disposed such that the first selection gear engages the drive gear in the first position of the rocker mechanism, and the second selection gear engages with the drive gear in the second position of the rocker mechanism. 
         [0019]    The robot may further comprise a linear actuator, which may be a solenoid, controlled by the electronic controller, configured to pivot the rocker mechanism between its first and second positions. 
         [0020]    The turbine may comprise a shaft extending into the drive mechanism and comprising worm mounted or formed thereon, and the drive mechanism may comprise a worm gear disposed so as to engage the worm. 
         [0021]    According to another aspect of the present invention, there is provided a pool cleaning robot, which may be suction-powered, comprising a housing, two drive wheels for providing locomotion of the robot and being disposed external to the housing on opposite sides thereof, and a drive mechanism in drive communication with a source of mechanical motion and configured to rotate the drive wheels; the drive mechanism comprising at least one axle mounted with one of the drive wheels and a drive gear configured to drive it, the axle being in drive communication with a reversing mechanism comprising:
       first and second selection gears in drive communication with the source of mechanical motion such that they rotate in opposite angular directions from one other; and   a drive selection mechanism configured to selectively engage no more than one of the selection gears with the drive gear.       
 
         [0024]    The reversing mechanism may comprise a series of gears, including at least the selection gears, on a rocker mechanism configured to be pivoted between first and second positions; the rocker mechanism being disposed such that the first selection gear engages with the drive gear in the first position of the rocker mechanism, and the second selection gear engages with the drive gear in the second position of the rocker mechanism. 
         [0025]    The rocker mechanism may have a substantially arcuate form (i.e., in the form of an arc), the gears having axes perpendicular to the arc, wherein the selection gears are disposed at extreme ends of the arc. 
         [0026]    The rocker mechanism may comprise four gears and be configured to pivot about an axis which is coincidental with the axis of one of the gears. 
         [0027]    The robot may further comprise a linear actuator, which may be a solenoid, configured to pivot the rocker mechanism between its first and second positions. 
         [0028]    According to a further aspect of the present invention, there is provided a suction-powered pool cleaning robot comprising:
       a housing;   a fluid outlet, configured for connection to a suction hose, and a fluid inlet, with a fluid path therebetween;   a turbine at least partially disposed within the fluid path so as to extract energy from flow of fluid therethrough;   an electrical generator   two drive wheels for providing locomotion of the robot and being disposed external to the housing on opposite sides thereof;   a drive mechanism configured to be driven by the turbine and to rotate the drive wheels; and   an electrical control system comprising an electrical generator configured to be driven by the turbine, and an electronic controller configured to detect the power output by the electrical generator and to determine, based on the output, that the robot has encountered an obstacle, such as a wall.       
 
         [0036]    According to a still further aspect of the present invention, there is provided a suction-powered pool cleaning robot comprising:
       a housing;   a fluid outlet, configured for connection to a suction hose, and a fluid inlet, with a fluid path therebetween;   a turbine at least partially disposed within the fluid path so as to extract energy from flow of fluid therethrough; and   an electrical generator for providing power to the robot and configured to be driven by the turbine, and an electronic controller configured to regulate at least some of the operations of the robot;
 
the turbine being magnetically coupled to the electrical generator.
       
 
         [0041]    At least the electrical generator may be housed within a sealed casing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0042]    In order to understand the invention and to see how it may be carried out in practice, an embodiment will now be described, by way of a non-limiting example only, with reference to the accompanying drawings, in which: 
           [0043]      FIGS. 1A and 1B  are top and bottom perspective views, respectively, of a robot according to the present invention; 
           [0044]      FIG. 1C  is a cross-section view of the robot, taken along line II-II in  FIG. 1A ; 
           [0045]      FIG. 1D  is a top view of the robot, with a cover portion of a housing thereof removed; 
           [0046]      FIG. 2  is a perspective view of a water flow unit and a drive unit of the robot, with their respective covers removed; 
           [0047]      FIGS. 3A and 3B  are front and rear perspective views, respectively, of a drive mechanism of the robot; 
           [0048]      FIG. 4  is a detailed view of a portion of a gear train of the drive mechanism illustrated in  FIGS. 3A and 3B ; 
           [0049]      FIGS. 5A and 5B  are cross-sectional perspective views of the drive unit, illustrating a reversing mechanism thereof in its respective first and second operating positions, taken along line V-V in  FIG. 3A ; 
           [0050]      FIGS. 6A and 6B  are top perspective views of the water flow unit and drive unit, with the reversing mechanism in its respective first and second operating positions; and 
           [0051]      FIG. 7  is a cross-sectional view of a control unit of the robot. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0052]    As illustrated in  FIGS. 1A through 1D , there is provided a suction-powered pool cleaning robot, which is generally indicated at  10 . The robot comprises a main housing  12 , which contains therewithin a water flow unit  14 , a drive unit  16 , and a sealed control unit  18 . The robot  10  comprises, exterior to the housing  12 , two track assemblies  20  on opposite sides of the housing, and a brushwheel  22 . Each track assembly comprises a drive wheel  24 , a free wheel  26 , and a track  28  thereabout. 
         [0053]    The water flow unit  14  is designed to be connected to an external suction source (not illustrated), which draws water and debris from the bottom of the pool and filters it before returning it to the pool. Thus, the flow unit  14  comprises a fluid inlet  30 , adapted to be disposed, during use, facing and substantially adjacent the pool floor, and a fluid outlet  32 , which is adapted to be attached to a suction hose (not illustrated) which is in fluid communication with the external suction source. A fluid path, indicated by arrows  34  and through which the water drawn through the inlet  30  passes before exiting via the outlet  32  passes, is defined between the inlet and the outlet. 
         [0054]    As illustrated in  FIG. 2 , the flow unit  14  further comprises a turbine  36 , which is disposed such that some of its blades  38  are disposed within the fluid path. Water flowing from the inlet  30  to the outlet  32  rotates the turbine  36  in a working direction, as indicated by arrows  37 . The turbine  36  is associated with two shafts, e.g., coupled thereto or integral therewith, projecting from both sides thereof. A mechanical drive shaft  40  projects into the drive unit  16 , and a power shaft  42  projects toward the control unit  18 . Further constructional and functional considerations of the two shafts  40 ,  42  will be described below. 
         [0055]    As best seen in  FIGS. 3A and 3B  (with the mechanical drive shaft  40  included for reference), the drive unit  16  comprises a drive mechanism, which is generally indicated at  44  and is designed to use mechanical motion provided by the mechanical drive shaft  40  to provide angular motion to (i.e., rotate) the drive wheels  24  of the track assemblies  20 . Each drive wheel  24  may be rotated in the same angular direction, resulting in the robot  10  being driven in a substantially straight path, or in opposite angular directions, resulting in the robot  10  pivoting. Thus, the drive mechanism  44  comprises two axles: a constant axle  46 , which always rotates in the same angular direction when the turbine rotates in its working direction, and a reversible axle  48 , which may rotate in either direction when the turbine rotates in its working direction, as will be explained below. Each of the axles  46 ,  48  is mounted with and drives one of the drive wheels  24 . 
         [0056]    The constant axle  46  and its associated drive wheel  24  are driven directly by the mechanical drive shaft  40  of the turbine  36 . The mechanical drive shaft  40  comprises a worm  50 , either mounted thereon or formed integrally therewith. A worm gear  52  (e.g., a helical gear) is mounted on the constant axle  46  to cooperate with the worm  50  for rotating the constant axle upon rotation of the mechanical drive shaft  40 . It will be appreciated that by providing this direct drive relationship between the constant axle  46  and the mechanical drive shaft  40 , any reduction in speed of the robot caused by an external source will result in a reduction in speed of the turbine, irrespective of the rate of flow of water through the fluid path. The significance of this will be explained below. 
         [0057]    The reversible axle  48  is driven by a gear train, generally indicated at  54 , and which comprises first and second transmission gears  56 ,  58 , each mounted to one of the constant axle  46  and the reversible axle  48 , respectively, such that it rotates in tandem therewith, a transmission rod  60  (illustrated in hidden lines in  FIG. 4 ) with first and second rod gears  62 ,  64  mounted thereto, and a reversing mechanism  66 . The first transmission gear  56  may be formed integrally with the worm gear  52 . 
         [0058]    As best illustrated in  FIG. 4 , the reversing mechanism  66  is formed as an arcuate rocker mechanism, with four gears arranged parallely along its length. The extreme gears constitute first and second selection gears  68 ,  70 . One of the interior gears of the reversing mechanism  66  is the second rod gear  64 . The other interior gear is a reversing gear  72 . The reversing mechanism  66  comprises first and second rocker supports  74 ,  76 , formed as round projections and disposed coaxially to one another, which are used to support and balance the reversing mechanism  66 . Portions which are integrally formed with or rigidly attached to the drive unit  16  on either side of the reversing mechanism  66  are formed with round apertures adapted to snuggly receive therein the rocker supports  74 ,  76 , while still allowing them to rotate therein (e.g., a rolling element bearing, not illustrated, may be provided within each aperture). The first rocker support  74  is formed with a through-going aperture  82  adapted to rotatably receive therein the transmission rod  60  and/or the second rod gear  64 . (The through-going aperture  82  may be formed with two different internal diameters so as to rotatably receive therein both the transmission rod  60  and the second rod gear  64 .) Thus, the axis about which the reversing mechanism  66  pivots is the same axis about which the second rod gear  64  rotates. 
         [0059]    A biasing member, such as a spring  84 , is provided to keep the reversing mechanism  66 , in the absence of any external force, in its first operating position, i.e., pivoted such that the first selection gear  68  engages (i.e., is meshed with) the second transmission gear  58 , as illustrated in  FIG. 5A . 
         [0060]    As there are four gear meshings in the gear train between the first and second transmission gears  56 ,  58  when the reversing mechanism  66  is in its first operating position (a first between the first transmission gear and the first rod gear  62 ; a second between the second rod gear  64 , which rotates with the first rod gear, and the reversing gear  72 ; a third between the reversing gear and the first selection gear  68 ; a fourth between the first selection gear and the second transmission gear), both transmission gears, and thus both the constant axle  46  and the reversible axle  48 , rotate in the same direction when the reversing mechanism  66  is in its first operating position. (It is well known that each meshing between two gears such as spur gears results in the two gears rotating in opposite directions. Thus, an odd number of meshings between two gears results in the gears rotating in opposite directions, while an even number of meshings between two gears results in the gears rotating in the same direction.) 
         [0061]    When the reversing mechanism  66  is in its second position, as illustrated in  FIG. 5B , the second selection gear  70  engages the second transmission gear  58 . As there are three gear meshings in the gear train between the first and second transmission gears  56 ,  58  when the reversing mechanism  66  is in its second operating position (a first between the first transmission gear and the first rod gear  62 ; a second between the second rod gear  64 , which rotates with the first rod gear, and second selection gear  70 ; a third between the second selection gear and the second transmission gear), the transmission gears, and thus both the constant axle  46  and the reversible axle  48 , rotate in opposite directions when the reversing mechanism  66  is in its second operating position. In this way turning of the robot (i.e., pivoting about a vertical axis) is enabled. 
         [0062]    In order to facilitate the pivoting of the reversing mechanism  66  between its first and second operating positions, a linear actuator  86  (such as illustrated in  FIGS. 6A and 6B ), such as a solenoid, may be provided, e.g., external to the drive unit  16 , whose actuator arm  87  projects into the drive unit and is pivotally articulated to the reversing mechanism  66  such that actuation thereof pivots the reversing mechanism between its first and second operating positions. In the “rest” state of the linear actuator  86  (i.e., when no current is applied thereto), as illustrated in  FIG. 6A , the actuator arm  87  is fully extended. The spring  84  ensures that the actuator arm  87  is in this position, and thus that the reversing mechanism  66  maintains its first operating position, when the linear actuator is in its rest state. In the “active” state of the linear actuator  86  (i.e., when a current is applied thereto, causing linear movement of the actuator arm  87  in a direction indicated by arrow  85 ), as illustrated in  FIG. 6B , the reversing mechanism  66  is brought into its second operating position. 
         [0063]    It will be appreciated that as the operating position of the reversing mechanism  66  determines whether the robot  10  follows a substantially straight trajectory or executes a turn, the direction of movement of the robot may be controlled by the linear actuator  86 . 
         [0064]    In addition to the above-mentioned components, it will be appreciated that the drive unit  16  and/or the drive mechanism  44  comprise a number of bushings, bearings, etc., as necessary to ensure efficient operation of the drive mechanism. 
         [0065]    As illustrated in  FIG. 7 , the control unit  18  is a sealed compartment  89 , and comprises an electrical control system, which is generally indicated at  88 . The control system  88  is self-contained and self-sufficient, i.e., it comprises all components necessary to generate its own power at least during normal use of the robot  10  and to direct operation thereof. As such, it comprises an electrical generator  90  and an electronic controller  92 . The electrical generator  90  provides all the power necessary for the electronic controller  92 . In addition, a rechargeable battery or high-capacity capacitor (neither illustrated) may be provided to store an amount of backup power which may be necessary to power the electronic controller  92  during brief intervals when the generator  90  is not providing power. Since, as noted above, the control unit  18  is housed in a sealed compartment, ingress of water thereto, and subsequent damage thereby to components of the electrical control system  88 , is prevented. 
         [0066]    The electrical generator  90  can be any known generator, such as a dynamo, and is driven by the rotation of the turbine  36 . In order to maintain the control unit  18  as a sealed compartment, the power shaft  42  of the turbine  36  and the shaft  94  of the generator  90  may be magnetically coupled to one another (the juxtaposition of the power shaft of the turbine and the control unit is illustrated, e.g., in  FIG. 1D ). Thus, the power shaft  42  of the turbine  36  comprises magnets embedded therein, at least on or near the face thereof which substantially abuts the control unit  18 . Similarly, the generator is arranged within the control unit such that the generator shaft  94  faces the interior wall of the control unit  18  which faces the turbine  36 . A disk  96  with magnets  98  embedded therein may be provided on the generator shaft  94  to be coupled with the power shaft  42  of the turbine  36  and to drive the generator shaft. Thus, as there is no physical contact necessary between the power shaft  42  of the turbine  36  and the generator shaft  94 , it is not necessary to utilize any mechanism to couple the turbine and the generator  90  which may compromise the seal of the control unit  18 . 
         [0067]    The electronic controller  92  may be any known controller which may direct/regulate at least some of the operations of the robot, such as an integrated circuit, etc. It may be adapted to be pre-programmed with any known or novel scanning algorithm. In order to control the direction of movement of the robot  10 , it controls the linear actuator  86 . Wire leads (not illustrated) between the controller  92  and the actuator  86  carry control signals thereto. Since the leads are not moving parts, they may be passed from the controller  92  within the control unit  18  to the linear actuator  86  via an opening which may be subsequently sealed. Thus, the seal of the control unit  18  is maintained. 
         [0068]    In addition, the electronic controller  92  may be adapted to detect a wall, or any similar obstacle, based on feedback from the generator  90 . As explained above, due to the direct drive relationship between the constant axle  46  and the mechanical drive shaft  40 , any reduction in speed of the robot  10  caused by an external source will result in a reduction in speed of the turbine  36 , irrespective of the rate of flow of water through the fluid path. The reduced speed of the turbine  36  results in a reduced speed of the generator  90 , which is associated with a lower electrical output than is associated with the generator when the robot  10  moves at its normal speed. Consequently, when a wall is encountered, the reduction of speed of the robot  10  can be detected by the controller  92  by measuring a reduced electrical output of the generator  90 . As the robot  10  may temporarily experience a reduction in speed for reasons other than encountering a wall, the controller  92  may be adapted to determine that a wall has been encountered when one or more specific criteria associated with the reduction in power output by the generator, such as a predetermined time over which the output is reduced, the amount of the reduction, etc. 
         [0069]    It will be appreciated that the generator  90  and the controller  92  may each be housed in separate sealed compartments, and electrically connected via wire leads, with the points of entry of the leads into each container being sealed. 
         [0070]    Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.