Apparatus for improved subaqueous stability

Abstract

A locomotive element to be incorporated in an underwater device propelled on a supporting surface along a predetermined axis of motion. The locomotive element comprises at least one resilient surface that can be rolled on the supporting surface. The resilient surface has a plurality of flow-through passages substantially perpendicular to the axis of motion.

Description

FIELD OF THE INVENTION

The present invention relates to the stability of subaqueous traction vehicles. More particularly, it relates to an apparatus for improving the stability of underwater propelled devices, like swimming pool cleaning robots.

BACKGROUND OF THE INVENTION

There are many types of automatic pool cleaners available, exhibiting various navigational abilities and ways of cleaning the bottom of a pool.

For example, in U.S. Pat. No. 6,125,492 (Prowse), titled AUTOMATIC SWIMMING POOL CLEANING DEVICE, there was disclosed an automatic swimming pool cleaning device, which includes a flexible cleaning member designed to contact an underwater surface of the swimming pool. A tube is coupled to the cleaning member for connecting to the cleaning device to a water vacuum hose via hose adapter. Water and pool surface contamination is drawn from underneath the cleaning member up through the tube by suction to a water filter system before being returned to the pool. A flexible valve member is mounted proximate a throat region of the tube wherein as water is drawn up through the tube a decrease in pressure in the throat region causes the valve member to flex and momentarily interrupt the flow of water. The interruption to the flow of water through the tube results in a momentary differential of ambient pressure underneath the flexible cleaning member which enables the device to move forwards incrementally along the underwater surface of the pool.

U.S. Pat. No. 6,099,658 (Porat), titled APPARATUS AND METHOD OF OPERATION FOR HIGH-SPEED SWIMMING POOL CLEANER disclosed an apparatus and method for cleaning the bottom and vertical side walls of a swimming pool, pond or tank employing a robotic, self-propelled cleaner. The robot has a protective housing of conventional design, the cleaner being operated at a primary cleaning speed as it traverses the surfaces to be cleaned and until the cleaner housing emerges from the water along a sidewall of the pool; thereafter the cleaner operates at a secondary drive speed that is relatively slower than the primary speed and the cleaner thereafter reverses direction and descends for a pre-determined period of time at the slower secondary speed in order to permit the air entrained under the housing to escape without destabilizing the cleaner during descent. After the predetermined period of time, the cleaner resumes operation at the more rapid primary speed until the cleaner housing once again emerges from the water's surface, after which the cycle is repeated.

In U.S. Pat. No. 5,086,535 (Grossmeyer et al.) titled MACHINE AND METHOD USING GRAPHIC DATA FOR TREATING A SURFACE, there was disclosed a machine for treating a surface area within a boundary perimeter includes a self propelled chassis having a surface treating device mounted on it. A computing section is mounted on the chassis and a powered wheel (or each of plural powered wheels) has a motor module for receiving command signals from the computing section. A position sensor is coupled to the computing section for generating a feedback signal representing the actual position of the machine. A data loading device coacts with the computing section for transmitting data to such computing section. A data file stores graphic data developed from a graphic depiction representing the surface area to be treated as well as other data developed in other ways. The data file coacts with the computing section and transmits graphic and other data to it. The computing section is arranged for processing the data and the feedback signal and responsively generating command signals directed to each motor module. Such modules, and the motors controlled thereby, propel the machine over the surface area selected to be treated.

U.S. Pat. No. 5,569,371 (Perling) titled SYSTEM FOR UNDERWATER NAVIGATION AND CONTROL OF MOBILE SWIMMING POOL FILTER, disclosed an underwater navigation and control system for a swimming pool cleaning robot, having a driver, an impeller, a filter and a processor for controlling the driver and a signal-producing circuit. The system further includes a signal-detecting circuit mounted on the pool, an interface located on the ground in proximity to the pool and comprising a detector for receiving and processing data from the detecting circuit and for transmitting signals to the robot's processor. Determination of the actual robot location is performed by triangulation in which the stationary triangulation base is defined by at least two spaced-apart signal detectors and the mobile triangle apex is constituted by the signal-producing circuit carried by the robot.

U.S. Pat. No. 5,197,158 (Moini) titled SWIMMING POOL CLEANER, disclosed a vacuum powered automatic swimming pool cleaning device having a hollow housing supported on two pairs of device mover wheels. The housing includes a central water suction chamber in water flow communication with a water suction trough at the bottom of the housing and in water outlet communication with an external vacuum line, a gear train for driving one of the pairs of mover wheels, and pivoted directional control floats. The water suction chamber houses an axle mounted turbine wheel bearing water driven vanes with the turbine being rotated in one direction only by water flow through the chamber. The turbine axle bears a turbine power output drive gear which intermeshes with one or the other of two shift gears which in turn reversibly drive the gear train as dictated by the position of the directional control floats within the housing. The floats swing shift within the housing to shift the shift gears in response to the impact of the cleaning device on an obstruction on the pool floor or by the device impacting a vertical pool wall. The swing shift of the control floats reverses the rotation of the mover wheels and thus the direction of movement of the cleaning device on the pool floor.

U.S. Pat. No. 4,786,334 (Nystrom) titled METHOD OF CLEANING THE BOTTOM OF A POOL, disclosed a method of cleaning the bottom of a pool with the aid of a pool cleaner. The pool cleaner travels along the bottom of the pool and collects material lying at the bottom of the pool. The pool cleaner is arranged to travel to and fro in straight, parallel paths between two opposite walls of the pool. At the walls the pool cleaner is turned by rotating a half turn so that, after turning, it will have been displaced laterally perpendicular to the initial direction of travel.

In U.S. Pat. No. 4,593,239 (Yamamoto) titled METHOD AND APPARATUS FOR CONTROLLING TRAVEL OF AN AUTOMATIC GUIDED VEHICLE, there was disclosed an automatic guided vehicle detects marks located on a plurality of points along a route it travels using at least three sensors, selects the number of marks detected from each individual sensor as a reference value in accordance with the logic of majority, and stops when the reference value agrees with a predetermined value. Cumulative errors, caused by misdetection are thus avoided and, there is little cumulative error.

U.S. Pat. No. 4,700,427 (Kneppers), titled METHOD OF AUTOMATICALLY STEERING SELF-PROPELLED FLOOR-CLEANING MACHINES AND FLOOR-CLEANING MACHINE FOR PRACTICING THE METHOD, disclosed a method of automatically steering a self-propelled floor-cleaning machine along a predetermined path of motion on a limited area to be worked. A sequence of path segments stored in a data memory is retrieved, and the path segments traveled by the machine. Markings are recognized by at least one sensor and converted into course-correcting control commands actuating and/or steering the machine.

U.S. Pat. No. 3,979,788 (Strausak) titled MOBILE MACHINE FOR CLEANING SWIMMING POOLS, disclosed a mobile machine for cleaning swimming pools by suction removal of sediment from the bottom of the swimming pools comprises a water turbine driving a drive wheel in such a way that the machine follows a self-steered path on the bottom of the swimming pools. The drive wheel is capable of rotating about a vertical steering axle to prevent the machine from becoming blocked at a wall or in a corner of the swimming pools.

It is noted that covering efficiently and quickly the bottom (and side walls) of a swimming pool is not simple a task, and various scanning algorithms (see some of the above-mentioned patents for examples) were devised to try and overcome this complex problem. Contributing to the complexity of the navigational problem is the fact that even though a robot is generally programmed to travel in straight lines from side to side and take accurate turns, it is difficult to keep it on such path and turns are hard to direct accurately. In fact a travel pattern of a pool cleaning robot is more likely to be deviated as the robot is subjected to different conditions and forces such as its own weight, the pull and weight of its electric cord (if there exist one), underwater currents, different friction forces due to uneven surface elevation or texture, dirt on floor, asymmetrically (or even amorphically) shaped pools etc. A further factor that reduces the robot's traction is the fact that as the wheels or tracks of the robot turn, they drag a thin film of water underneath themselves, contributing to a hydroplaning effect.

Consequently it is desirable to introduce an apparatus that contributes to the stability of a pool cleaning robot.

It is the purpose of the present invention to provide a novel and improved apparatus for adding to the stability of an underwater propelled device, for example, a pool cleaning robot traveling on the bottom and side walls of a swimming pool.

Another aim of the present invention is to provide such an apparatus that enables a pool cleaning robot to better maintain its line of movement.

Other advantages and aspects of the present invention will become apparent after reading the present specification and viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE INVENTION

It is therefore thus provided, in accordance with a preferred embodiment of the present invention, a locomotive element to be incorporated in an underwater device propelled on a supporting surface along a predetermined axis of motion, the locomotive element comprising at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.

Furthermore, in accordance with a preferred embodiment of the present invention, the element is in the form of a wheel.

Furthermore, in accordance with a preferred embodiment of the present invention, the element is in the form of a track.

Furthermore, in accordance with a preferred embodiment of the present invention, the element is in the form of a drum.

Furthermore, in accordance with a preferred embodiment of the present invention, the flow-through passages are located in a plurality of protrusions provided on the resilient surface.

Furthermore, in accordance with a preferred embodiment of the present invention, there is provided a pool cleaning robot comprising a motorized drive; an impeller driven by a pump motor; power supply; and locomotive elements coupled to the motorized drive for propelling the robot on a supporting surface along a predetermined axis of motion, each of the locomotive elements comprising:

at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.

Furthermore, in accordance with a preferred embodiment of the present invention, each of the locomotive elements is in the form of a wheel.

Furthermore, in accordance with a preferred embodiment of the present invention, each of the locomotive elements is in the form of a track.

Furthermore, in accordance with a preferred embodiment of the present invention, each of the locomotive elements is in the form of a drum.

Furthermore, in accordance with a preferred embodiment of the present invention, the flow-through passages are located in a plurality of protrusions provided on the resilient surface.

Furthermore, in accordance with a preferred embodiment of the present invention, there is provided a method for enhancing stability of a locomotive element, used to propel an underwater propelled device along a predetermined axis of motion, the method comprising:

providing the underwater propelled device with locomotive elements, each of the locomotive elements comprising:

at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.

BRIEF DESCRIPTION OF THE FIGURES

In order to better understand the present invention, and appreciate its practical applications, the following Figures are provided and referenced hereafter. It should be noted that the Figures are given as examples only and in no way limit the scope of the invention as defined in the appending claims. Like components are denoted by like reference numerals.

FIG. 1a illustrates a sectional view of a pool cleaning robot in accordance with the present invention.

FIG. 1b illustrates the bottom view of a pool cleaning robot in accordance with the present invention.

FIG. 2 illustrates an isometric view of a pool cleaning robot wheel in accordance with a preferred embodiment of the present invention.

FIG. 3a illustrates a side view of a pool cleaning robot wheel in accordance with a preferred embodiment of the present invention.

FIG. 3b illustrates a rear view of a pool cleaning robot wheel in accordance with a preferred embodiment of the present invention.

FIG. 4a illustrates a side view of a pool cleaning robot belt or track in accordance with another preferred embodiment of the present invention.

FIG. 4b illustrates a side view of a pool cleaning robot belt or track in accordance with yet another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND FIGURES

A main aspect of the present invention is the provision of a pool-cleaning robot with a novel and unique stabilization mechanism that helps maintain the robot's direction of motion.

Reference is now made to FIG. 1a illustrating a sectional view of a pool cleaning robot 40 in accordance with the present invention. A robot housing 42 houses a motor drive 48 for driving the axles 44 (optionally a brush or sponge 54 may be added) on which ends wheels 46 are attached to the caterpillar tracks, an impeller 52 oriented horizontally (to pump water from the pool floor upwards into the robot), driven by a pump motor 50 (with ingress cover 51), control unit 56, central processing unit (CPU) 58 and wall encounter sensor 60.

The pumped dirt and foliage are collected inside a filter bag that is positioned inside the housing along the pump. Power cable 62 goes through the housing 42 to provide power to the robot electric components. In other preferred embodiments of the present invention no power cable is provided and instead the robot is powered by battery.

FIG. 1b illustrates the bottom view of a pool cleaning robot in accordance with the present invention. Twin parallel caterpillar tracks 43 are provided, stretched over and motivated by wheels 46, which are motivated by axle 44. Also attached to axles 44 are wheel elements 80.

The robot shown in FIGS. 1a and 1b is driven by a single motor (drive motor 48). Usually pool cleaning robots targeted for small and medium sized pools are provided with a single motor drive, whereas for twin motor drive is popular in large pools cleaning robots. Single motor drive can be reversed by employing provided transmission to reverse the direction of the rotation of the wheel axles, but it cannot be used to turn the robot sideways.

The stabilization mechanism that comprises the present invention, shown in FIG. 2, comprises a series of resilient flow-through passages 82 in the perimeter 88 of one or more of those robot elements 80 that are in contact directly or indirectly with the pool bottom (and sides). In a preferred embodiment of the present invention the element is one or more members of a set wheels 90.

Passage 82 passes from one side 88 of the wheel to the other. In a preferred embodiment of the present invention, the passage is implemented as a cavity running from one side of the wheel to the other in a protrusion 84, the passage being open at each end. Protrusions 84 are located around the perimeter of wheel element 80 and are separated by open recesses 86. Passage 82 can equally be implemented in other manners by one skilled in the art and still have the functionality described here. For example, passages 82 could be inserted into a perimeter without protrusions 84 and recesses 86, however these elements have the advantage of adding traction.

Wheel element 80 fits onto an axle or other form of locomotion. (In FIG. 2 the center 90 of element 80 is shaped to fit on the axle.)

As wheel element 80 turns, and a region of the perimeter with a passage in it starts to come into contact with the bottom (or sides) of the pool, the leading end of the passage is pressed closed between the bottom and the wheel by gravity and by the suction forces of the robot pump 50 (when on a side wall only the suction forces apply). Water in the passage starts to be pushed out to either side, creating two counterbalancing stream vectors in opposing directions perpendicular to the plane of rotation. This continues until the cavity is completely compressed (directly at the bottom of the rotation of the wheel). As the wheel continues to turn, the leading end of the passage is released from contact with the bottom, the resilient passage starts to spring back out to its original shape, and water rushes back into the passage, again creating a pair of counterbalancing stream vectors in opposing directions perpendicular to the plane of rotation. The stream vectors taper off as the passage fully returns to its original volume. In both cases, where the water is forced out and where it rushes back in, the net result of the counterbalancing forces is to increase the stability of the wheel element 80, hence increasing the stability of the robot and minimizing the effects of other forces acting in directions other than the direction of motion on the wheel element 80.

In other words: when the passage is brought to a position between the underwater device and the supporting surface, it is pressed closed thereby producing two outward streams through the ends in opposing directions that are substantially perpendicular to the axis of motion, and when the passage exits the position between the underwater device and the supporting surface, it regains its original shape thereby producing two inward streams through the ends in opposing directions that are substantially perpendicular to the axis of motion, thereby enhancing the stability of the locomotive element.

FIG. 3a is a side view of the present invention with dotted arrows showing the direction of forces. Shown is the axis of motion, the rotation, the force of gravity and suction, the outward force 94 perpendicular to the wheel element 80 from water being forced out of passage 82 as protrusion 84 is compressed, and the inward force 96 from water flowing back into passage 82 as protrusion 84 regains its shape. Forces 94 and 96 are perpendicular to the plane of the side of the wheel and should be seen as lying on the axis coming out of the drawing (which cannot be shown in a two dimensional drawing).

FIG. 3b is a rear view of wheel element 80 showing forces 94 and 96. Again, force 94 derives from water being pushed out the two sides as protrusion 84 is flattened. Force 96 derives from the opposite mechanism: as protrusion 84 regains its shape, water rushes into passage 82, creating equal forces perpendicular to the plane of rotation.

The mechanism of the present invention can be implemented in various ways, the only requirement being that the element 80 is regularly compressed and released. Typically this would be done by having element 80 implemented as a rotating locomotive element in contact with the pool bottom (walls), although the compression/release could be effected by some type of powered mechanical element.

Note that the term “locomotive element”, for the purpose of the present invention, refers to any kind of intermediary element between the driving power of an underwater propelled device and the supporting surface on which the device is propelled, which physically causes the device to move (e.g. wheels, tracks, drums etc.)

Element 80 may be implemented in a cylindrical form (like a drum) used as a single locomotion element across the width of the robot (in which case two such wheel elements are to be used).

FIG. 4a shows an alternative embodiment of the present invention where element 80 has been implemented as a caterpillar track.

FIG. 4b shows an alternative embodiment of the present invention where element 80 has been implemented as drive wheels for a caterpillar track.

The stabilization mechanism of the present invention is not limited to a particular type of swimming pool cleaning robot or particular shape, depth, or volume of swimming pool.

Note that although in the present specification and accompanying drawings the submerged robot was illustrated as having a single motor, the present invention is not limited to a single-motor robot. In fact the present invention is applicable to any submerged robots, with any number of motors or pumps.

It should be clear that the description of the embodiments and attached Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope as covered by the following claims.

It should also be clear that a person skilled in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the following claims.

Claims

1. A locomotive element to be incorporated in an underwater device propelled on a supporting surface along a predetermined axis of motion, the locomotive element comprising at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.

2. The locomotive element of claim 1, wherein it is in the form of a wheel.

3. The locomotive element of claim 1, wherein it is in the form of a track.

4. The locomotive element of claim 1, wherein it is in the form of a drum.

5. The locomotive element of claim 1, wherein the flow-through passages are located in a plurality of protrusions provided on the resilient surface.

6. A pool cleaning robot comprising a motorized drive; an impeller driven by a pump motor; power supply; and locomotive elements coupled to the motorized drive for propelling the robot on a supporting surface along a predetermined axis of motion, each of the locomotive elements comprising:

at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.

7. The robot of claim 6, wherein each of the locomotive elements is in the form of a wheel.

8. The robot of claim 6, wherein each of the locomotive elements is in the form of a track.

9. The robot of claim 6, wherein each of the locomotive elements is in the form of a drum.

10. The robot of claim 6, wherein the flow-through passages are located in a plurality of protrusions provided on the resilient surface.

11. A method for enhancing stability of a locomotive element, used to propel an underwater propelled device along a predetermined axis of motion, the method comprising:

providing the underwater propelled device with locomotive elements, each of the locomotive elements comprising:

at least one resilient surface that can be rolled on the supporting surface, said at least one surface having a plurality of flow-through passages substantially perpendicular to the axis of motion.