Pool cleaning device with improved bottom topography

Abstract

The pool cleaning device of the invention has a housing bottom with an elliptically-beveled suction hole inlet and optional topographical features that facilitate smooth flow of water to and into the suction hole so as to improve capture of tree leaves and other debris. The optional topographical features include a sloped bottom along the leading edge to minimize the possibility of debris catching on the outer edge of the housing bottom, a bottom suction cavity with or without partitions designed to direct debris toward the elliptically-beveled suction hole inlet, and a fender that partially wraps around a cylindrical rotary brush along the leading edge of the housing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part (CIP) of U.S. patent application Ser. No. 12/455,163 to Dewing (filed 29 May 2009), the teachings of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is concerned with swimming pools and spas, and in particular with means of cleaning and removing debris from swimming pools and spas.

2. Description of the Related Art

Swimming pool suction cleaning devices of the prior art typically comprise a rectangular housing having a substantially planar bottom with a centrally located suction hole connected to a suction means via a hose attached to a tubular outlet on the housing top. The cleaning device is moved along the pool bottom so that the housing bottom remains substantially parallel and in close proximity with the bottom of the swimming pool while water from the swimming pool is sucked through a small bottom gap between the housing bottom and the swimming pool bottom. In some cases, wheels or housing bottom protrusions are used to provide a bottom gap that is more uniform and/or optimum in width. The housing may also be made of a flexible material so that the housing bottom tends to conform to curved areas of the pool bottom. Such devices are reasonably effective for removing dirt from the pool bottom but cannot efficiently capture debris larger than the bottom gap of the device. And the bottom gap is typically very small so as to provide the fast water flow rate needed to efficiently remove dirt from the swimming pool bottom.

Various modifications designed to improve the effectiveness of pool cleaning devices have been described in the prior art. For example, U.S. Pat. No. 5,048,149 to Heinen (issued 17 Sep. 1991) describes a pool cleaning device having a fixed brush attached along the leading edge of the housing so as dislodge dirt particles by sweeping the pool surface. Such brushes tend to push debris along the pool bottom rather than direct it to the suction hole.

Some pool cleaning suction devices of the prior art provide the needed narrow bottom gap via a lip around the perimeter of a housing bottom that circumscribes a bottom suction cavity containing a means for improving the effectiveness of the device. For example, U.S. Pat. No. 5,842,243 to Horvath et al. (issued 1 Dec. 1998) describes a pool cleaning suction device having a fixed brush pivotally mounted inside a bottom suction cavity such that the brush angle changes depending on the direction of movement of the device. U.S. Pat. No. 4,402,101 to van Zyl (issued 6 Sep. 1983) describes a pool cleaner device comprising an elongated brush rotated by an electric motor and located inside the bottom suction cavity so that dirt dislodged by the sweeping action of the rotating brush is effectively captured by the device. U.S. Pat. No. 6,942,790 to Dolton (issued 13 Sep. 2005) describes a pool cleaning suction device having two cylindrical scrubbing brushes mounted inside the bottom suction cavity that are rotated in opposing directions by a mechanical drive motor.

Such prior art devices are ineffective for removing bits of debris that are too large to pass through the narrow bottom gap between the housing bottom perimeter and the pool surface. Tree leaves are particularly difficult to capture using the devices of the prior art since the leaves are often highly non-planar so that they do not readily pass through the small bottom gap needed to vacuum dirt from pool surfaces. Furthermore, tree leaves and other debris tend to hang up and accumulate at the inlet to the suction hole and other sharp edges of prior art pool cleaner devices.

U.S. Pat. No. 5,664,275 to Sebor (issued 5 Sep. 1997) describes a pool cleaning suction device having an oscillator that periodically widens the bottom gap around the perimeter of a bottom suction cavity so as to periodically capture larger bits of debris. The Sebor '275 device is relatively complicated and does not provide continuous capture of debris.

U.S. Pat. No. 5,001,800 to Parenti et al. (issued 26 Mar. 1991) describes a pool cleaning suction device comprising a hydraulic turbine motor that drives two pairs of wheels having rubber band treads to provide locomotion, and drives a cam that raises one of the pairs of treaded wheels off the pool bottom to provide steering. Parenti '800 further describes use of the motor to drive rotation of a cylindrical brush located along the front of the housing but does not indicate that it provides improved effectiveness for capturing large bits of debris. The Parenti '800 device is relatively complicated and is not well suited for use in small residential swimming pools.

U.S. Patent Application Publication 2006/0174430 to Pareti (published 10 Aug. 2006) describes a swimming pool cleaning device that includes an ultrasonic wave generator in a housing bottom cavity designed to dislodge adherent materials from the submerged pool surfaces. The Pareti '430 device further comprises an electric motor that drives rubber treads via drive wheels to move the device along the pool surface, and three rotary brushes. The larger brush is located within the housing bottom cavity and the two smaller brushes are located outside the housing on the leading and trailing edges. The Pareti '430 device is designed to remove recalcitrant deposits, such as limestone scale, rust, sludge and weeds, via a combination of ultrasound and scrubbing. This device is relatively complicated and is not well suited for use in small residential swimming pools. The Pareti '430 publication provides no indication that the device provides improved effectiveness for capturing large bits of debris.

As evident from the examples above, most prior art efforts to improve pool cleaning devices have focused on removal of dirt and scale deposits rather than debris. Consequently, rotary brushes incorporated in prior art devices have typically been located within the suction cavity where they are ineffective as aids for capturing debris too large to directly pass through the bottom gap of the device. Prior art pool cleaning devices also tend to be powered by an electric or hydraulic motor and often include steering mechanisms, making them too bulky, complicated and expensive for use in small residential swimming pools. There is a need for a relatively simple pool cleaning device that effectively removes both dirt and debris, especially tree leaves, from swimming pool bottoms.

Recent U.S. Patent Application Publication 2010/0299863 to Dewing (published 2 Dec. 2010) describes a manually operated pool cleaning device that is useful for removing both dirt and debris from a swimming pool bottom. The Dewing '863 pool cleaning device comprises a rectangular housing connected to a suction means via a hose; at least four transport wheels rotatably attached to the rectangular housing via transport wheel axles so as to enable the pool cleaning device to be rolled along the swimming pool bottom with the long housing sides perpendicular to the direction of motion; two cylindrical rotary brushes each rotatably attached via a brush axle to the housing along one of the opposing long housing sides such that the bristles of the cylindrical rotary brush contact the swimming pool bottom; and at least two rotary drive mechanisms whereby rotation of the transport wheels, produced by rolling the pool cleaning device along the swimming pool bottom, drives rotation of the cylindrical rotary brush on the leading edge of the pool cleaning device in the same rotational direction as the transport wheels. The rotary brush on the leading edge of the Dewing '863 pool cleaning device produces a downward sweeping action that tends to flatten tree leaves and other debris so that they can be sucked through a small bottom gap between the housing bottom planar area and the swimming pool bottom.

SUMMARY OF THE INVENTION

The present invention provides a pool cleaning device having an elliptically-beveled suction hole inlet and optionally other topological features on the bottom of the device housing that facilitate smooth flow of water to and into the suction hole so as to improve capture of tree leaves and other debris from a submerged surface of a swimming pool or a spa. Optional topographical features that may be included in a device of the invention having a rectangular housing, comprise: sloped edges along each of the housing long sides such that the spacing between the housing bottom and the submerged surface of the pool is increased on the outside edges of the housing perpendicular to the direction of motion to minimize the possibility of debris catching on the outer edge of the housing bottom; and a bottom suction cavity designed to channel debris toward the elliptically-beveled suction hole inlet. The bottom suction cavity may comprise sloped sides, especially along the short housing sides, and/or partitions to improve uniformity of water flow along the long housing sides. Sloped suction cavity sides may be flat, curved or have segments with different slopes. A device according to the invention comprising a cylindrical rotary brush mounted outside the housing along a housing long side may further comprise a curved fender that partially wraps around the top of the rotary brush so as to increase water flow through the bottom portion of the rotary brush to enhance capture of debris.

In a preferred embodiment, the device of the invention comprises: a rectangular housing with two transport wheels attached to each short side of the housing; a centrally-located suction hole with a hemiellipsoidal inlet whose long axis is substantially parallel with the housing long sides; a suction cavity on the bottom of the housing having sides that are sloped along the short housing sides to improve the uniformity of water flow along the housing long sides, and partitions to direct debris toward the hemiellipsoidal suction hole inlet; a tubular outlet for connecting the suction hole outlet to a suction means via a hose; a pole attachment fitting enabling the pool cleaning device to be rolled along the submerged surface of the pool with the long housing sides perpendicular to the direction of motion; two cylindrical rotary brushes rotatably attached along the outside edges of the housing long sides; two rotary drive mechanisms whereby rotation of the transport wheels as the cleaning device is manually moved along the pool bottom drives rotation of the cylindrical rotary brush on the leading edge of the pool cleaning device in the same rotational direction as the transport wheels; sloped edges along each of the housing long sides such that the spacing between the housing bottom and the submerged surface of the pool is increased adjacent to the cylindrical brushes; and two curved fenders each attached along one of the housing long sides so as to partially wrap around the top of one of the cylindrical rotary brushes and increase water flow through the bottom portion of the brush.

The hemiellipsoidal suction hole inlet of the pool cleaning device of the invention is simple but highly effective for removing tree leaves and other debris, especially when combined with the other bottom topographical features of the invention and a rotary brush along the leading edge of the device. The device may be designed to be manually-operated or motor-driven so that it is well-suited for cleaning both large and small swimming pools and spas.

Further features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts top (A), bottom (B) and side (C) views of a basic embodiment of the pool cleaning device of the invention wherein a substantially constant bottom gap is maintained by means of spacers along the short sides of a rectangular housing.

FIG. 2 schematically depicts top (A), bottom (B) and side (C) views of a basic embodiment of the pool cleaning device of the invention wherein a substantially constant bottom gap is maintained by means of transport wheels on the short sides of a rectangular housing.

FIG. 3 schematically depicts top (A), side (B) and end (C) views of a preferred embodiment of the pool cleaning device of the invention.

FIG. 4 schematically depicts a bottom view (A) and an end cross-sectional view (B) of the preferred embodiment of the pool cleaning device of FIG. 3.

FIG. 5 shows computer-generated oblique (FIG. 5A) and perpendicular (FIG. 5B) views of the top of a prototype pool cleaning device according to the invention.

FIG. 6 shows computer-generated oblique (FIG. 6A) and perpendicular (FIG. 6B) views of the bottom of the prototype pool cleaning device of FIG. 5.

These figures are not to scale and some features have been enlarged for better depiction. The housing is depicted in these figures as though transparent to better illustrate details of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Terminology used in this document is generally known to those skilled in the art. The term “rectangular housing” denotes the overall shape of the housing rather than a rigid mathematical geometry. The generic term “pool” encompasses both swimming pools and spas. The terms “hemielliptically-beveled” and “hemiellipsoidal” are equivalent and denote the overall shape of the beveled suction hole inlet rather than a rigid mathematical geometry. The term “housing bottom planar area” also applies to the same area when the housing bottom is curved so as to conform to the curvature of the swimming pool bottom. The term “debris” denotes any small object that may need to be removed from a swimming pool, tree leaves, bits of paper, and candy wrappers, for example.

The term “rotatably attached” when applied to a wheel, gear or pulley having an axle denotes that the wheel, gear or pulley may rotate about the axle or that the axle may rotate, or both. Axles employed in the pool cleaning device of the invention may be rotatably attached to housings, wheels, gears and pulleys in blind or through-holes via any suitable means, including those selected from the group consisting of slip fit, bushing, ball bearing, roller bearing, and combinations thereof. Wheels, gears and pulleys may be retained on axles by any suitable means, including those selected from the group consisting of split ring, cotter pin, retaining nut, and combinations thereof. The term “fastened” denotes that a wheel, gear or pulley is firmly attached so as to rotate with rather than around an axle. Wheels, gears and pulleys may be fastened to axles via any suitable means, including those selected from the group consisting of press fit, spline, cog, ratchet connection, and combinations thereof. Such attachment, retaining and fastening devices are well known in the art and are not depicted in the figures.

The present invention provides a pool cleaning device for removing dirt and debris from a submerged surface of a pool, comprising: a housing having a centrally-located suction hole with an elliptically-beveled inlet on the bottom of the housing and a tubular outlet on the top of the housing for connecting the suction hole to a suction means; a means of moving the pool cleaning device along the submerged surface of the pool; and a means of maintaining a substantially constant bottom gap between the bottom of the housing and the submerged surface of the pool as the pool cleaning device is moved along the submerged surface of the pool. Other topological features may be included on the bottom of the device housing to facilitate smooth flow of water to and into the suction hole so as to further improve capture of tree leaves and other debris from a submerged surface of a swimming pool or a spa.

The pool cleaning device of the invention may comprise a housing of any suitable shape, a rectangle or a pentagon, for example, and may include spacers, wheels or both to provide a uniform bottom gap between the housing bottom of the device and the submerged surface of the pool. The device of the invention may further comprise one or more manually-driven or motor-driven rotary brushes, preferably located outside the housing along one of the housing sides. The device of the invention may be moved along the submerged surface of a pool manually or by means of a motor. Preferably, the long axis of the hemiellipsoid defined by the elliptically-beveled suction hole is substantially perpendicular to the direction of motion of the pool cleaning device over the submerged surface of the pool.

FIG. 1 schematically depicts top (A), bottom (B) and side (C) views of a basic embodiment of a pool cleaning device of the invention, which has a rectangular housing 121 with a centrally-located suction hole 112 having an elliptically-beveled inlet 112a and a suction fitting 122 for attaching to a suction means via a hose. Elliptically-beveled inlet 112a defines a hemiellipsoid having a bottom ellipse 112b in the same plane as housing bottom planar area 111 or a parallel plane thereto. The hemiellipsoid defined by elliptically-beveled inlet 112a may have any suitable orientation and any suitable dimensions. The long axis of the hemiellipsoid is preferably oriented to be substantially perpendicular to the direction of motion of the pool cleaning device (parallel to the long sides of a device with a rectangular housing). Bottom ellipse 112b depicted in FIG. 1 has a short axis that is substantially equivalent to the diameter of suction hole 112.

For the device of FIG. 1, a substantially constant bottom gap 129 is maintained between housing bottom planar area 111 and the submerged surface of a pool by means of spacers 128a and 128b attached to housing bottom planar area 111 along the short sides of housing 121. This basic device also includes a pole attachment fitting 123 having a depressible pin 124 for connecting to a pole, and is connected to the top of housing 121 via a swivel pin 125 attached to the housing top via attachment blocks 126 and 127. Any of the various pole attachment fittings commercially available may be used with the pool cleaning device of the invention. A pole attachment fitting providing a steering capability to facilitate pushing the pool cleaning device back and forth in swaths covering the pool bottom is preferred. Tubular outlet fitting 122 typically press fits to the suction hose but may be of any suitable type, and may include a locking mechanism.

Any suitable suction means may be used with the pool cleaning device of the invention. A variety of suitable suction means are known in the art. Swimming pools are generally equipped with a skimmer and a filter pump and the suction provided by this equipment is typically suitable for use with the pool cleaning device of the invention. Typical water flow rates are in the 25 to 70 gallons per minute range.

FIG. 2 schematically depicts top (A), bottom (B) and side (C) views of a preferred embodiment of the pool cleaning device of the invention which, similar to the device of FIG. 1, has a rectangular housing 221 with a centrally-located suction hole 212 having an elliptically-beveled inlet 212a and a suction fitting 222 for attaching to a suction means via a hose. This device also includes a pole attachment fitting 223 having a depressible pin 224 for connecting to a pole, and is connected to the top of housing 221 via a swivel pin 225 attached to the housing top via attachment blocks 226 and 227. The device of FIG. 2, however, includes four transport wheels 231, 232, 233 and 234 attached via axles 231a, 232a, 233a and 234a, respectively, to the short sides of housing 221, which enable the device to be rolled along the submerged surface of a pool while a substantially constant bottom gap 229 is maintained. Note that the first digit of the numbers used to designate the various parts of the device of the invention in the figures corresponds to the figure number and the last two digits are the same from figure to figure for substantially equivalent parts. Discussions of some parts may not be repeated for subsequent figures.

For the preferred device of FIG. 2, the length of the short axis of bottom ellipse 212b is smaller than the inside diameter of suction hole 212. In this case, suction hole 212 is constricted by a step or lip 213 so as to enhance water flow along the long axis of the hemiellipsoid defined by elliptically-beveled inlet 212a and provide more uniform water flow along the long sides of housing 221. For optimum water flow uniformity, the long axis of bottom ellipse 212b should be at least twice the inside diameter of suction hole 212, and the height of the inlet hemiellipsoid relative to housing bottom planar area 211 (or the top surface of a bottom suction cavity) is preferably at least 5 millimeters. The optimum shape and dimensions of the inlet hemiellipsoid depend on the shape and dimensions of the device housing.

The pool cleaning device of the invention may include optional topographical bottom features that further improve the capture of tree leaves and other debris by the hemiellipsoidal suction hole inlet. One improvement is provided by a sloped edge along at least one side of the housing to provide a graded spacing between the housing bottom and the submerged surface of the pool on the leading edge of the pool cleaning device to minimize the possibility of debris catching on the outer edge of the housing bottom. Additional improvement may also be provided by a bottom suction cavity with or without one or more partitions to direct the flow of water and debris toward the elliptically-beveled suction hole inlet. The top of the bottom suction cavity preferably comprises inclined areas on either side of the suction hole that slope down to intersect the bottom planar area at an angle, reducing the depth of the suction cavity near the short housing sides and improving the uniformity of water flow into the housing along the housing long sides. For pool cleaning devices with a cylindrical rotary brush along the leading edge outside the housing, a fender that is attached to the housing and wraps around the top of the rotary brush may be used to enhance capture of tree leaves and other debris by increasing water flow through the bottom portion of the brush.

A preferred embodiment of the pool cleaning device of the invention comprises: (1) a rectangular housing having two short and two long housing sides; (2) a housing bottom with a centrally-located suction hole having an elliptically-beveled inlet and sloped edges along each of the long housing sides; (3) a housing bottom suction cavity having sloped sides along the housing short sides to improve uniformity of water flow along the housing long sides; (4) one or more partitions within the bottom suction cavity to direct the flow of water and debris toward the elliptically-beveled suction hole inlet; (5) a housing top with a pole attachment fitting and a tubular outlet for connecting the suction hole to a suction means via a hose; (6) at least four transport wheels rotatably attached to said rectangular housing via transport wheel axles so as to enable the pool cleaning device to be rolled along the submerged surface of the pool with the long housing sides perpendicular to the direction of motion and the width of the bottom gap between the housing bottom and submerged surface of the pool remaining substantially constant; (7) two cylindrical rotary brushes each having a brush axle rotatably attached at both ends to said rectangular housing so as to be parallel with the transport wheel axles and adjacent to one of the opposing long housing sides such that the bristles of said cylindrical rotary brushes contact the swimming pool bottom; (8) at least two rotary drive mechanisms whereby rotation of said transport wheels, produced by rolling the pool cleaning device along the submerged surface of the pool, causes at least one of said cylindrical brushes to rotate about its brush axle in the same rotational direction as said transport wheels; (9) two curved fenders each attached to said rectangular housing along one of the housing long sides so as to partially wrap around the top of one of said cylindrical rotary brushes; (10) at least two and preferably four support wheels located on the housing bottom around the periphery of the suction hole so as to maintain the spacing between the housing bottom and the submerged surface of the pool around the suction hole substantially uniform and constant at the predetermined value; and (11) a sufficient amount of weight, attached to said housing, to press said transport wheels against the swimming pool bottom with sufficient force to produce adequately fast rotation of said cylindrical rotary brushes. Tree leaves and other debris are effectively captured as the pool cleaning device, connected to a suction means, is rolled back and forth over the swimming pool bottom by an operator pulling and pushing on a pole attached to the pole attachment fitting.

The housing of the pool cleaning device of the invention may be constructed of any suitable material that is chemically compatible with pool water and provides adequate strength, durability and flexibility. The rectangular housing preferably comprises a polymer material that can be readily molded and/or machined, and has sufficient flexibility to allow the housing bottom to at least partially conform to curvature of the swimming pool bottom. A preferred method of fabrication is injection molding.

FIG. 3 schematically depicts top (A), side (B) and end (C) views of a preferred embodiment of a pool cleaning device 300 according to the invention, comprising a rectangular housing 301, four transport wheels 331, 332, 333 and 334, two cylindrical rotary brushes 341 and 342, two rotary drive mechanisms 351 and 352 whereby rotation of transport wheels 332 and 333 drives rotation of cylindrical rotary brushes 342 and 341, respectively. In FIG. 3 and subsequent figures, the rectangular housing is rendered as though transparent in order to better depict the rotary drive mechanisms, wheel axles, cylindrical brushes and brush axles. Rectangular housing 301 has a housing bottom 311 with a bottom planar area and a centrally-located elliptically-beveled suction hole 312, and a housing top 321 with a pole attachment fitting 323 and a tubular outlet 322 for connecting suction hole 312 to a suction means via a hose. Transport wheels 331, 332, 333 and 334 are attached in pairs to the opposing short sides of rectangular housing 301 via transport wheel axles 331a, 332a, 333a and 334a, respectively, so as to enable pool cleaning device 300 to be rolled along the submerged surface of a pool with the long housing sides and the long axis of the hemiellipsoidal suction hole inlet perpendicular to the direction of motion and the width of the bottom gap between the bottom planar area of housing bottom 311 and the submerged surface of the pool remaining substantially uniform and constant at a predetermined value. Cylindrical rotary brushes 341 and 342 have respective brush axles 341a and 342a that are rotatably attached at both ends to rectangular housing 301 so as to be parallel with wheel axles 331a, 332a, 333a and 334a and adjacent to the opposite long housing sides such that the bristles of said cylindrical rotary brushes contact the submerged surface of the pool.

As indicated in FIG. 3(C) for transport wheels 333 and 334, each of the transport wheels of the pool cleaning device preferably comprises a hub and a tire. The transport wheel tires preferably comprise a rubber-like material that provides good traction and is non-marking (does not leave marks on the submerged surface of the pool). Any suitable rubber-like material may be used.

Any suitable type of rotary drive mechanism may be used, including direct drive, belt drive, gear drive, and combinations thereof. A belt or gear drive such that the rotary brushes rotate at a faster rate than the transport wheels, preferably at least 50% faster, is preferred. The rotary drive mechanisms of the invention preferably include a ratchet gear or ratchet pulley device such that rotation of the transport wheels causes the cylindrical brush on the leading edge of the pool cleaning device to rotate but does not cause the cylindrical brush on the trailing edge of the pool cleaning device to rotate. In this case, the force required to move the pool cleaning device manually along the pool bottom is reduced without affecting the performance of the pool cleaning device. Suitable ratchet gear and ratchet pulley devices are well-known in the art.

For the preferred pool cleaning device of FIG. 3, the rotary drive mechanisms comprise gear trains 351 and 352 comprising transport wheels 332 and 333 and drive gears 351a and 352a respectively fastened to transport wheel axles 332a and 333a, intermediate gears 351b and 352b rotatably fastened to housing 301 via intermediate gear axles, and brush gears 351c and 352c respectively fastened to the axles of brushes 342 and 341. Rotation of the transport wheels causes the drive gears to rotate in the same rotational direction, the intermediate gears to rotate in the opposite direction, and the brush gears and brushes to rotate in the same rotational direction as the transport wheels. One of the gears in each of the gear trains is preferably a ratchet gear such that only the brush on the leading edge is caused to rotate by rotation of the transport wheels. The gear trains of the pool cleaning device may comprise three coplanar gears, as depicted in FIG. 3, but may alternatively comprise any suitable number of gears of any suitable diameters arranged in any configuration providing rotation of the rotary brush on the leading edge of the pool cleaning device at a suitable rotation rate in the same rotational direction as the transport wheels. The term “gear” encompasses both gears with interlocking cogs, and smooth gears engaged via friction.

The cylindrical rotary brushes may be any suitable diameter and may comprise any suitable material or combination of materials. The brush bristles may comprise metallic wires, such as stainless steel, brass or bronze, but preferably comprise polymer strands. The brush axles, which may be solid cylinders or twisted strands, preferably comprise a metal, such as stainless steel, brass or bronze, but may comprise a polymer material, such as Nylon® or Delrin®. A suitable brush diameter is 3.2 cm (1.25 inches).

The preferred device of FIG. 3 further comprises curved fenders 371 and 372 each of which is attached to rectangular housing 301 along one of the housing long sides so as to partially wrap around the tops of cylindrical brushes 341 and 242, respectively, and increase water flow through the bottom portions of brushes 341 and 342 so as to enhance capture of debris. Curved fenders 371 and 372 may be segmented, via slits (not shown), for example, to enhance flexibility so that housing 301 can better conform to the curvature of the submerged pool surface. Curved fenders 371 and 372 may be attached using fasteners, such as screws, or may be an integral part of housing 301 formed by injection molding, for example.

For the preferred pool cleaning device of FIG. 3, housing bottom 311 is sloped along the long sides of housing 301 so as to provide housing bottom sloped edges 381 and 382 such that the spacing between the housing bottom and the submerged surface of the pool is wider adjacent to brushes 341 and 342 and tapers toward the long centerline of housing 301. Housing bottom sloped edges 381 and 382 are designed to enhance capture of debris, which would otherwise tend to hang up at the sharp bottom edges of housing 301. Housing bottom sloped edges 381 and 382 may have any suitable slope and may be planar or curved.

The preferred embodiment of FIG. 3 further comprises weights 361 and 362 attached to housing 301. The amount of added weight should be sufficient to press the transport wheels against the submerged surface of the pool with sufficient force to produce adequately fast rotation of the cylindrical rotary brushes. The amount of weight needed depends largely on the suction force provided by the suction means employed. Weights 361 and 362 may be attached to housing 301 using fasteners, such as screws, or may be integrated into housing 301, via injection molding, for example. Weights 361 and 362 preferably comprise a relatively dense metal. The added weight may comprise any number of weights distributed in any suitable manner.

FIG. 4 schematically depicts a bottom view (A) and an end cross-sectional view (B), which better illustrate bottom features of the preferred embodiment of the pool cleaning device of FIG. 3. The housing bottom planar area 411 circumscribes elliptically-beveled suction hole 412 and defines a bottom gap between the housing bottom planar area 411 and the submerged surface of the pool. The bottom gap should be sufficiently uniform and narrow in width to provide the uniformly high water flow rate needed to effectively remove dirt from the pool bottom and pull dirt and debris to the suction hole. The optimum bottom gap depends on the size and specific shape of housing 401 and housing bottom planar area 411, and on the suction means employed. A bottom gap of approximately 3 mm is typically suitable.

A preferred embodiment of the pool cleaning device of the invention comprises at least two and preferably four support wheels located on the housing bottom around the periphery of the suction hole so as to maintain the width of the spacing between the housing bottom and the submerged surface of the pool around the suction hole substantially uniform and constant at the predetermined value. Such support wheels are especially useful for pool cleaning devices with housings that are relatively wide and flexible, for which sagging of the housing due to suction and gravity tends to reduce water flow locally and consequently the effectiveness of the pool cleaning device. Support wheels are preferably located in wheel wells in the bottom of the housing that may result in wheel well protrusions on the top surface of the housing. The preferred pool cleaning device of FIGS. 3 and 4 comprises four support wheels 491, 492, 493 and 494 (FIG. 4) in respective wheel wells 391, 392, 393 and 394 (FIG. 3) that protrude above top surface 321 of housing 301.

FIG. 4 also illustrates a preferred bottom suction cavity 480 having a trapezoidal cross-section defined by bottom planar area 411, inclined sidewalls 483 and 484, and cavity top surface 485. Bottom suction cavity 480 tends to provide a stream of water toward elliptically-beveled suction hole 412 so as to enhance capture of debris. Suction cavity top area 485 preferably comprises inclined areas 485a and 485b on either side of suction hole 412 that slope down to intersect bottom planar area 411 at an angle. This reduces the depth of suction cavity 480 along the short sides of housing 401 so that the uniformity of water flow into the housing along the housing long sides is improved. Preferably, as indicated in FIG. 4, the segments 411a and 411b of bottom planar area 411 that run along the short housing sides are also reduced in width to further improve the water flow uniformity along the housing long sides.

FIG. 4 also illustrates bottom partitions 495 and 496 that protrude into suction cavity 480 from suction cavity top surface 485 and help direct water flow to elliptically-beveled suction hole 412 so as to enhance capture of debris. Such bottom partitions may be of any suitable shape and size. Bottom partitions preferably extend downward to be substantially coplanar with bottom plane 411 so as to effectively channel water toward elliptically-beveled suction hole 412. Branched bottom partitions have been found to be particularly effective.

Within the scope of the invention, the elliptically-beveled suction hole may be used alone or in combination with any of the other features of the invention, including a rotary brush, a rotary brush fender, a housing bottom sloped edge, a bottom suction cavity and a housing bottom partition. The rotary brush may be continuous or segmented, and may be supported by intermediate brush axle supports. Intermediate brush axle supports may be needed for relatively wide pool cleaning devices having flexible housings and brush axles so that the housing bottom tends to conform to curvature of the pool bottom. A brush axle may also comprise two or more individual brush axle segments so as to increase the flexibility of a rectangular housing. Transport wheels and rotary cylindrical brushes may be attached directly to a housing or via cantilevered cross-beams that overhang the housing sides.

DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred pool cleaning device according to the invention comprises a rectangular housing with an elliptically-beveled suction hole and two transport wheels attached to each of its short sides, a rotary brush adjacent to each of the housing long sides and driven by rotation of a transport wheel via a gear rotary drive mechanism that includes a ratchet connection, four recessed support wheels located around the periphery of the suction hole, two curved fenders each of which is attached to the housing and partially wraps around the top of one of the cylindrical rotary brushes, and a housing bottom that includes housing bottom sloped edges along the housing long sides, a bottom suction cavity that comprises partitions and inclined top surface areas on either side of the suction hole. The housing and the brush axles are preferably flexible so that the pool cleaning device tends to conform to curvature in the swimming pool bottom. For sufficiently wide devices, the flexible brush axle should be supported by intermediate brush axle supports attached to the housing.

Prototype Pool Cleaning Device

FIG. 5 shows computer-generated oblique (FIG. 5A) and perpendicular (FIG. 5B) views of the top of a prototype pool cleaning device according to the invention. The housing 501 of the prototype device had four transport wheels 531-534 (two on each of the short housing sides) and two cylindrical rotary brushes 541 and 542 along each of the long housing sides, each brush having two intermediate brush axle supports 541a/541b and 542a/542b, respectively. The prototype device comprised two curved fenders 571 and 572 that partially wrapped around the tops of cylindrical rotary brushes 541 and 542, respectively. To increase flexibility of housing 501 so that the device would better conform to curvature in the submerged surface of the pool, fenders 571 and 572 were divided into segments via slits (as indicated). The prototype device further comprised eight attached weights 561-568 and a combination tubular suction hole outlet 522 and pole attachment fitting 523 (FIG. 5A).

FIG. 6 shows computer-generated oblique (FIG. 6A) and perpendicular (FIG. 6B) views of the bottom of the prototype pool cleaning device depicted in FIG. 5. The bottom of housing 601 of the prototype device comprised a suction hole 612 with an elliptically-beveled suction hole inlet 612b, four recessed support wheels 691-694 located around the periphery of suction hole 612, sloped edges 681 and 682 along the housing long sides, a bottom suction cavity 680 (having a trapezoidal center cross-section defined by bottom planar area 611, inclined sidewalls 683 and 684, and top cavity area 685) that was divided by partitions 695 and 696 along the centerline of the housing on either side of the suction hole. Partitions 695 and 696 further comprised branch partitions 695a/695b and 696a/696b, respectively, as indicated in FIG. 6. The top cavity area 685 had end sections 685a and 685b that sloped down to bottom planar area 611 such that the width of bottom planar area 611 along the short housing sides was minimal.

The rectangular housing of the prototype device was approximately 51 cm wide (long side not including the transport wheels), 19 cm long and 3.5 cm tall (not including the hose connection (5.1 cm outside diameter) which extended 2.6 cm above the top of the housing). The prototype housing was constructed of a resin photopolymer (mechanically similar to ABS and BPT plastics) using a computer-controlled laser polymerization process. A more flexible material is preferred for production devices.

The four transport wheels of the prototype device were 2.5 cm wide and had an overall diameter of 8.5 cm (including a non-marking tire about 1.0 cm thick), and were each attached to the housing via a transport wheel axle (1.5 cm diameter) and a plastic bushing. The four recessed support wheels were 1.4 cm wide and had an overall diameter of 3.4 cm, and were positioned around the suction hole as indicated in FIG. 6B. The bottom gap between the bottom planar area and the submerged surface of the pool was 2.4 mm.

The cylindrical rotary brushes of the prototype device had an overall diameter of 3.2 cm (1.25 inches) and comprised Nylon® bristles attached to a non-metallic brush axle 3.0 mm in diameter. The cylindrical rotary brushes were driven at 1.5 times the rotation rate of the transport wheels via rotary drive mechanisms comprising three Nylon® gears each and including a ratchet connection.

The prototype housing included integral segmented curved fenders that wrapped around the top of each cylindrical rotary brush with approximately 3 mm clearance between the curved fenders and the brush bristles. The housing bottom long edges were sloped at 17° over a distance of 1.6 cm so that the spacing between the housing bottom and the submerged surface of the pool increased to 3.2 mm adjacent to the cylindrical rotary brushes.

The housing bottom of the prototype device included a rectangular bottom suction cavity approximately 3 mm deep (relative to the bottom planar area) whose sides sloped up from the insides of the bottom planar area (51 cm×16 cm) to a rectangular top cavity area (31 cm×7 cm). The bottom suction cavity was divided by two branched partitions coplanar with the bottom planar area (see FIG. 6) on either side of the suction hole inlet. The width of the bottom planar area was 3 mm along the housing long sides and minimal along the housing short sides.

The suction hole of the prototype device had an inside diameter of 4.4 cm, which was reduced in the elliptically-beveled region to 3.6 cm by an overhang of the elliptical bevel. The hemiellipsoid defined by the elliptically-beveled suction hole inlet had a depth of approximately 2.0 cm (relative to the suction cavity top area) and its bottom ellipse had a short axis of 3.6 cm (0.4 cm lip on two opposite sides of the suction hole) and a long axis of 15.1 cm.

The prototype device was shown to be highly effective for removing tree leaves and other debris from the submerged surfaces of a swimming pool. Those skilled in the art will appreciate that some benefit according to the invention could be provided by elliptical suction hole inlets having a wide range of dimensions (hemiellipsoid depth and bottom ellipse short and long axes), and the optimum configuration and dimensions will depend on the type and size of the pool cleaning device.

The preferred embodiments of the present invention have been illustrated and described above. Modifications and additional embodiments, however, will undoubtedly be apparent to those skilled in the art. Furthermore, equivalent elements may be substituted for those illustrated and described herein, parts or connections might be reversed or otherwise interchanged, and certain features of the invention may be utilized independently of other features. Consequently, the exemplary embodiments should be considered illustrative, rather than inclusive, while the appended claims are more indicative of the full scope of the invention.

Claims

1. A pool cleaning device for removing dirt and debris from a submerged surface of a pool, comprising:

a housing having a centrally-located suction hole with an elliptically-beveled inlet on the bottom of the housing and a tubular outlet on the top of the housing for connecting the suction hole to a suction means;

a means of moving the pool cleaning device along the submerged surface of the pool; and

a means of maintaining a substantially constant bottom gap between the bottom of the housing and the submerged surface of the pool as the pool cleaning device is moved along the submerged surface of the pool,

whereby tree leaves and other debris are more effectively captured as the pool cleaning device, connected to a suction means, is moved along the submerged surface of the pool.

2. The pool cleaning device of claim 1, wherein the housing bottom has a sloped edge along at least one side of the housing to provide a graded spacing between the housing bottom and the submerged surface of the pool on the leading edge of the pool cleaning device to minimize the possibility of debris catching on the outer edge of the housing bottom.

3. The pool cleaning device of claim 1, wherein the housing has a bottom suction cavity.

4. A pool cleaning device for removing dirt and debris from a submerged surface of a pool, comprising:

a rectangular housing having two short and two long housing sides, a housing bottom with a housing bottom planar area and a centrally-located suction hole having an elliptically-beveled inlet, and a housing top with a pole attachment fitting and a tubular outlet for connecting the suction hole to a suction means via a hose; and

at least four transport wheels rotatably attached to said rectangular housing via transport wheel axles so as to enable the pool cleaning device to be rolled along the submerged surface of the pool with the long housing sides perpendicular to the direction of motion and the width of the bottom gap between the housing bottom and submerged surface of the pool remaining substantially constant,

whereby tree leaves and other debris are effectively captured as the pool cleaning device, connected to a suction means, is rolled back and forth over the swimming pool bottom by an operator pulling and pushing on a pole attached to the pole attachment fitting.

5. The pool cleaning device of claim 4, wherein two of said transport wheels are attached to each of the opposite housing short sides.

6. The pool cleaning device of claim 4, further comprising:

at least two and preferably four support wheels located on the housing bottom around the periphery of the suction hole so as to maintain the spacing between the housing bottom and the submerged surface of the pool around the suction hole substantially uniform and constant at the predetermined value.

7. The pool cleaning device of claim 4, wherein the housing bottom has sloped edges along each of the long housing sides to provide a graded spacing between the housing bottom and the submerged surface of the pool on the leading edge of the pool cleaning device to minimize the possibility of debris catching on the outer edge of the housing bottom.

8. The pool cleaning device of claim 4, wherein the housing comprises a bottom suction cavity having a top surface.

9. The pool cleaning device of claim 8, wherein the top surface of the suction cavity comprises inclined areas on either side of suction hole that extend to the housing bottom planar area.

10. The pool cleaning device of claim 8, wherein the bottom suction cavity comprises one or more partitions to direct the flow of water and debris toward the elliptically-beveled suction hole inlet.

11. The pool cleaning device of claim 4, further comprising:

two cylindrical rotary brushes each having a brush axle rotatably attached at both ends to said rectangular housing so as to be parallel with the transport wheel axles and adjacent to one of the opposing long housing sides such that the bristles of said cylindrical rotary brushes contact the swimming pool bottom; and

at least two rotary drive mechanisms whereby rotation of said transport wheels, produced by rolling the pool cleaning device along the submerged surface of the pool, causes at least one of said cylindrical brushes to rotate about its brush axle in the same rotational direction as said transport wheels,

whereby tree leaves and other debris are more effectively captured due to a downward sweeping action produced by rotation of the cylindrical rotary brush on the leading edge as the pool cleaning device, connected to a suction means, is rolled back and forth over the submerged surface of the pool by an operator pulling and pushing on a pole attached to the pole attachment fitting.

12. The pool cleaning device of claim 11, further comprising:

two curved fenders each attached to said rectangular housing along one of the housing long sides so as to partially wrap around the top of one of said cylindrical rotary brushes and increase water flow through the bottom portion of the brush so as to enhance capture of tree leaves and other debris.

13. The pool cleaning device of claim 11, further comprising:

a sufficient amount of weight, attached to said housing, to press said transport wheels against the swimming pool bottom with sufficient force to produce adequately fast rotation of said cylindrical rotary brushes.

14. The pool cleaning device of claim 11, wherein said rotary drive mechanisms are geared such that said cylindrical brushes rotate at a rotational rate that is greater than the rotational rate of said transport wheels.

15. The pool cleaning device of claim 11, wherein said rotary drive mechanisms include a ratchet connection such that rotation of the transport wheels causes the cylindrical brush on the leading edge of the pool cleaning device to rotate but does not cause the cylindrical brush on the trailing edge of the pool cleaning device to rotate.

16. The pool cleaning device of claim 11, wherein the brush axles and the housing are flexible so that the housing bottom tends to conform to curvature of the swimming pool bottom.

17. The pool cleaning device of claim 11, wherein each of the brush axles is supported at one or more intermediate locations between the ends of the brush axle by one or more brush axle supports fastened to said rectangular housing.

18. The pool cleaning device of claim 11, further comprising:

at least two cantilevered cross-beams perpendicular to the long sides of said rectangular housing,

wherein the axles of said transport wheels and said cylindrical rotary brushes are rotatably connected to the ends of said cantilevered cross-beams.

19. The pool cleaning device of claim 11, wherein each of the brush axles comprises two or more individual brush axle segments so as to increase the flexibility of said rectangular housing so that the housing bottom can better conform to curvature of the swimming pool bottom.

20. A pool cleaning device for removing dirt and debris from a submerged surface of a pool, comprising:

a rectangular housing having a housing bottom with a centrally-located suction hole with an elliptically-beveled inlet, and a housing top with a tubular outlet for connecting the suction hole to a suction means;

at least four transport wheels rotatably attached to said rectangular housing so as to enable the pool cleaning device to be moved along the submerged surface of the pool with the width of the bottom gap between the housing bottom and submerged surface of the pool remaining substantially constant;

at least one cylindrical rotary brush whose bristles contact the submerged surface of the pool; and

at least one electrical motor that drives rotation of at least one of the transport wheels, at least one of the rotary brushes, or both.