Patent Publication Number: US-6658674-B2

Title: Self-draining swimming pool cover

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. application Ser. No. 09/794,877 filed Feb. 27, 2001, which is now U.S. Pat. No. 6,487,733 to which priority is claimed, the disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a swimming pool cover and, more particularly, to a self-draining swimming pool cover. 
     2. Description of the Related Art 
     For years owners of swimming pools have had to deal with the problems associated with water collecting on the top of the pool cover when the pool is not in use. For example, the weight of an excessive amount of water may cause the cover to tear or it may cause damage to the sides of the pool. In colder climates, the water on the cover may freeze thereby compounding the problem. Also, the water that collects on top of the cover often becomes dirty or contaminated with algae, presenting an unsightly and unsanitary condition. If the cover tears, and upon removal of the cover from the pool, it is difficult to prevent the dirty water from entering the clean pool water. Therefore, while the cover is on the pool the owner is burdened with the continuing task of pumping or siphoning the water off of the cover. 
     Several attempts have been made to solve the problems associated with excessive accumulations of water on top of the pool cover. For example, U.S. Pat. No. 4,233,695 to Rowney and U.S. Pat. No. 5,259,078 to Crandall disclose swimming pool covers with rain water drainage and filter means. Although these patents adequately drain the water from the cover, the water within the pool becomes contaminated. Other designs offer solutions to the potential contamination problem resulting from allowing the water to drain into the pool. For example, U.S. Pat. No. 4,318,421 to Ward and U.S. Pat. No. 4,830,040 to Eng disclose float controlled siphon discharge valve mechanisms which operate to drain water from a swimming pool cover. 
     More simple designs are also in the prior art. For example, U.S. Pat. No. 3,184,764 to West discloses a swimming pool cover having a drain in the central portion thereof to drain all water off of the top of the pool cover. West &#39;764 also discloses a screen installed over the drain opening to prevent leaves, dirt and other trash from clogging the drain opening. Additionally, U.S. Pat. No. 5,802,629 to Zeitek is also directed to a self-draining pool cover. Zeitek &#39;629 includes a pool cover having an aperture with a drain fitting attached to the aperture positioned in a central portion of the pool cover. A flexible hose connects the drain fitting to an outlet assembly in the pool wall. A primary objective and feature of West &#39;764 and Zeitek &#39;629 patents is to drain all of the water off of the swimming pool cover. However, quite often it is desirable to maintain a predetermined amount of water on top of the pool cover to keep the pool cover from becoming damaged from flapping around in the wind. 
     Attempts have also been made to provide a self-draining pool cover with provisions to maintain a predetermined volume of water on top of the cover. For example, U.S. Pat. No. 4,819,681 to Hodak is directed to a method and apparatus for draining a swimming pool cover. In Hodak &#39;681, the apparatus for draining a swimming pool cover includes a drainage device connected to a conduit which is connected to a discharge port fitting in the side of the pool. To maintain a predetermined amount of water on top of the pool cover, the drainage device also includes a vertical drain tube which extends upwardly a predetermined distance. Thus, the tube permits excess accumulated water at a level above the top edge of the drain tube to flow into the tube bore and drain through the conduit to be discharged from the pool. 
     However, notwithstanding the above advances in the art, a need still exists for a simple, self-draining swimming pool cover that fully drains all water surrounding the drain fitting while still maintaining a predetermined amount of water on top of the pool cover. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a simple, self-draining swimming pool cover that fully drains all water surrounding the drain fitting while still maintaining a predetermined amount of water on top of the pool cover. 
     One embodiment of the present invention is a drain assembly for a pool cover which includes a drain fitting positioned in a hole formed in the pool cover; a screen connected to the pool cover and positioned above the drain fitting to minimize the amount of debris entering the drain fitting; a barrier assembly connected to the pool cover adjacent to a perimeter of the screen to maintain a predetermined volume of water on the pool cover; and a flexible conduit connected at a first end to an outlet end of the drain fitting. A second end of the conduit is connected to an opening formed in a side of the pool. 
     The drain fitting includes a flange member and a nut. The flange member includes an upper circular ring with an elongate neck extending therefrom. The upper circular ring and elongate neck define an axial bore through the flange for draining water that passes through the screen. The elongate neck includes a plurality of threads on an outer periphery thereof for engaging threads formed on an inner circumference of the nut. The drain fitting may further include an elbow fitting connected to a lower end of the flange member to minimize any stress exerted by the conduit. 
     The barrier assembly includes a tubular shaped buoyant material housed within a pocket formed by two sections of material. 
     In another embodiment of the present invention, the drain assembly for a pool cover includes a drain fitting positioned in a hole formed in a section of material; a screen connected at its perimeter to the section of material such that at least a portion of the screen is positioned above the drain fitting to minimize the amount of debris entering the drain fitting; a barrier assembly connected to the section of material adjacent to a perimeter of the screen to maintain a predetermined volume of water on the pool cover; and a flexible conduit connected at a first end to an outlet end of the drain fitting. The section of material preferably has either a reflective surface or a black surface. 
     These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments, which is to be read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the invention, reference is made to the following description of exemplary embodiments thereof, and to the accompanying drawings, wherein: 
     FIG. 1 is a side view illustrating a self-draining swimming pool cover in accordance with the present invention; 
     FIG. 2 is a top view illustrating a first layer of the self-draining swimming pool cover in accordance with the present invention; 
     FIG. 3 is a top view illustrating a second layer of the self-draining swimming pool cover in accordance with the present invention; 
     FIG. 4 is a plan view of the pool cover with the drain assembly; 
     FIG. 5 is an isometric sectional view illustrating a float; and, 
     FIGS. 6 and 7 are plan views of the pool cover showing additional float arrangement. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present disclosure describes a simple, self-draining swimming pool cover that fully drains all water surrounding the drain fitting while still maintaining a predetermined amount of water on top of the pool cover. 
     Referring now in specific detail to the drawings in which like reference numerals identify similar or identical elements throughout the several views, and initially to FIG. 1, one embodiment of a self-draining swimming pool cover constructed in accordance with the present disclosure is shown generally as self draining swimming pool cover  10 . 
     Self-draining swimming pool cover  10  includes a pool cover  12  having a drain assembly  14  connected thereto. Drain assembly  14  includes a first layer  16  and a second layer  18 . First layer  16  includes a screen portion  20  and a barrier assembly  22 . Second layer  18  includes a drain fitting  24  positioned within a section of material  26 . 
     Pool cover  12  is preferably formed of a vinyl or other flexible plastic water impervious material. The peripheral edge regions (not shown) of the pool cover  12  are affixed to the perimeter of a swimming pool by weights, clamps or the like, all in a manner known to one having ordinary skill in the art. 
     Screen portion  20  constitutes the center portion of first layer  16  and is provided to prevent leaves, sticks and other debris from blocking the bore of drain fitting  24  while allowing water to pass therethrough. Also, since the screen  20  will allow water to pass therethrough, any debris remaining on top of the screen will be held out of contact with the water. Therefore, the debris will not become or remain water-logged and will not mat down so as to clog the screen and prevent the flow of water therethrough. Eventually, the debris will blow away with the wind thereby leaving the screen as well as the rest of the cover clean and free of dirt and debris. 
     Barrier assembly  22  ensures that a volume of water remains on the cover to assist in keeping the cover in position during windy weather. Barrier assembly  22  is preferably formed by placing a buoyant material  28 , such as Styrofoam® brand foamed polymer, within a pocket formed by two sections of cover material  30  and is attached to the cover  12  around the perimeter of the screen  20 . Buoyant material will ensure that the cover  12  floats above the water level in the pool thereby creating a barrier between the cover  12  and the drain assembly  14 . The pocket is preferably formed by attaching two sections of cover material together by stitching, welding or any other means known to one having ordinary skill in the art. An opening may be left in the pocket to facilitate the insertion of material  28  afterwards, or the pocket may be formed around material  28 . Screen  20  and cover  12  are connected on either side of barrier assembly  22  by sandwiching the screen  20  and cover  12  between the two sections of cover material  30  and holding them in place by stitching. 
     Second layer  18  may be attached directly to pool cover  10  or it may be attached to first layer  16 , either by stitching or another means known to one having ordinary skill in the art. Material  26  is preferably the same material that is used to fabricate cover  12 . However, in colder climates, it is preferred that material  26  has an upper surface that is either silver in color and reflective, or a dark color such as black. The purpose of having either a reflective surface or a dark colored surface is to create an area which will be warmer than the surrounding area due to the absorption of the radiant energy of the sun. Accordingly, this area will tend to be less susceptible to the formation of ice around drain fitting  24 . 
     Drain fitting  24  defines an opening positioned in a portion of the cover (preferably the central portion). A reinforcing patch  38  is preferably attached to the pool cover at the location at which drain fitting  24  will be installed. A lower end of drain fitting  24  is connected to a first end of a conduit  32  for discharging water which enters the opening in the drain fitting. Typically, a hose clamp will be employed to facilitate the connection between the drain fitting and the conduit. A second end of the conduit may be connected to an opening in a side of the swimming pool, a pump, or the pool&#39;s filter system (not shown). Conduit  32  is preferably formed of a flexible hose to maintain the required flexibility in the event that the pool cover rises and falls with the level of water in the pool. It is also preferable to connect an elbow  34  to the lower end of drain fitting  24  to facilitate easier connection of conduit  32  and to reduce the amount of stress placed on the drain fitting by conduit  32 . 
     Drain fitting  24  includes a flange  34  and a nut  36 . The flange  34  includes a substantially flat upper circular ring with an elongate neck extending therefrom. The upper ring  34 A has a diameter which is greater than a diameter of the neck  34 B. The upper ring  34 A and the elongate neck  34 B together define an axial bore through flange  34 . 
     The elongate neck  34 B includes a plurality of threads on an outer periphery thereof. Nut  36  is configured and dimensioned having threads on an inner surface to threadably engage the elongate neck  34 B. Thus, when nut  36  is threaded onto the elongate neck  34 B it is tightened against the upper ring  34 A of flange  34  and drain fitting  24  is secured to material  26 . 
     Alternatively, nut  36  may be secured to flange  34  by another means such as epoxy, welding, an interference fit or any other means known to one having ordinary skill in the art. Two rubber gaskets may be placed over the elongate neck  34 B on either side of material  26  to prevent leakage into the pool when nut  36  is tightened against the upper ring  34 A of flange  34 . 
     During manufacture of the self-draining pool cover in accordance with the present invention, the elongate neck of flange  34  is inserted into a hole formed in a pool cover from an upper surface of the pool cover. Alternatively, the elongate neck  34 B of flange  34  may be installed through a hole formed in a separate section of material  26  wherein the section of material  26  is subsequently connected to a larger opening in pool cover  12 . From below the pool cover, nut  36  is then screwed on to the portion of the elongate neck  34 B which extends through the cover, to lock the cover between the nut and the upper ring of flange  34 . Conduit  32  is then connected to a lower portion of drain fitting  24 . Barrier assembly  22  and screen portion  20  are then attached to cover  12  in a location to overlay the drain fitting. 
     Referring now to FIG. 2, a top view of the first layer  16  of the self draining swimming pool cover in accordance with the present invention is illustrated. As shown, screen  20  forms the central portion of first layer  16 . As represented by the dashed lines around the perimeter of screen  20 , screen  20  is attached to two sections of cover material  30  by stitching. Although shown in a circular configuration, screen  20  may be a square, triangle or any other shape. Screen  20  is preferably approximately twenty-four inches in diameter. 
     Adjacent to the outer circumferential periphery of screen  20  is barrier assembly  22 , which includes, as discussed above, buoyant material  28  housed within two sections of cover material  30 . Again, as represented by the dashed lines, the two sections of cover material  30  are stitched together to house buoyant material  28  therebetween. 
     The resulting first layer  16  may then be attached within a cut-out in a pool cover by stitching first layer  16  to the pool cover, as represented in FIG. 2, by the dashed lines around the perimeter of first layer  16 . The solid line illustrated adjacent to the perimeter of first layer  16  represents the preferred location at which second layer  18  is attached to first layer  16 . 
     Referring now to FIG. 3, a top view of the second layer  18  of the self draining swimming pool cover in accordance with the present invention is illustrated. As illustrated, a reinforcement patch  38  is attached to a central portion of material  26  by stitching, epoxy or any other means known to one having ordinary skill in the art. A hole is then formed through material  26  and reinforcement patch  38  and drain fitting  24  is installed through the hole. The solid line illustrated adjacent to the perimeter of second layer  18  represents the preferred location at which second layer  18  is attached to first layer  16 . 
     Referring now to FIG. 4, pool cover  12  includes a drain assembly  14  having a first layer  16  stitched thereto. Buoyant barrier assembly  22  includes a buoyant material secured therein as explained above. The buoyant material can be closed cell polymer foam (e.g., Styrofoam® brand), or a buoyant polymer rope. The ends of the rope are brought together and joined by, for example, heat or solvent welding to form a ring. Sheet metal material  26  and drain fitting  24  are covered by mesh  20  which prevents leaves and other debris from entering the drain fitting  24 . Sheet material  26  is preferably metallized (e.g., with aluminum) to provide at least a partially reflective surface. First layer  16  is preferably stitched to pool cover  12  by means of peripheral double-line stitching  17   a . As added reinforcement, and to prevent the formation of air bubbles between first layer  16  and the pool cover, X-shaped double stitching  17   b  at the corners of the first layer are used to secure the first layer  16 . 
     Referring now to FIGS. 5,  6 , and  7 , additional floats can be incorporated into the pool cover to maintain buoyancy across the pool cover  12 . Additional floats are advantageous for large size pool covers to prevent portions of the cover from sagging and accumulating pockets of water. 
     Referring to FIG. 5, a sewn-in float  40  includes a buoyant material  41  secured to the top surface of pool cover  12  by cover material  13  which is attached to pool cover  12  by peripheral stitching  15 . Buoyant material  41  can be any suitable material such as polymeric foam (e.g. Styrofoam® brand) or any material or object having a density less than water. Cover material  13  can be the same material as pool cover  12  and is preferably a polymer sheet. Stitching  15  is preferably double stitching. 
     Referring particularly now to FIG. 6, a circular self-draining swimming pool cover  50  is shown which includes a pool cover  12   a  drain assembly  14  and a plurality of floats  40 . Preferably, at least four inner floats  40 A are symmetrically arranged as opposite pairs such that imaginary lines between each pair together form a cross. The four inner floats  40 A are each equidistant from the respective edge of the drain assembly  14  by a distance D-1. Depending upon the size of the pool cover, a second set of outer floats  40 B may optionally also be included in the self draining swimming pool cover  50 . Floats  40 B are positioned outward from and in alignment with corresponding inner floats  40 A in a symmetrical cross-like configuration. Outer floats  40 B are each equidistant from the respective edge of the drain assembly  14  by a distance D-2. 
     By way of illustration, the following Table I sets forth exemplary distances for various pool cover diameters D. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 POOL COVER 
                   
                   
               
               
                 DIAMETER D 
                 D-1 
                 D-2 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 8 
                 feet 
                 No floats 40A 
                 No floats 40B 
               
               
                 12-15 
                 feet 
                 24 inches 
                 No floats 4GB 
               
               
                 18-21 
                 feet 
                 36 inches 
                 No floats 4GB 
               
               
                 24-27 
                 feet 
                 36 inches 
                 72 inches 
               
               
                   
               
            
           
         
       
     
     Referring now to FIG. 7, oval shaped self draining swimming pool cover  51  with floats  40  is illustrated wherein inner floats  40 A are spaced from the drain assembly  14  a distance D-3 and optional outer floats  40 B are spaced apart from the drain assembly  14  a distance D-4. The outer floats  40 B are generally only positioned, if needed, along the major axis of the pool cover  12 . Typically, for pool covers ranging in size from about 10′×16′ to about 12′×18′ (smaller distance is the length of the minor diameter, larger distance is the major diameter) only floats  40 A are needed and D-3 is approximately 24 inches distance between inner floats  40 A and the drain assembly  14 . 
     For pool covers ranging in size from about 12′×24′ to about 16′×25′, floats  40 A and  40 B are included wherein D-3 is about 24″ and D-4 is about 48″. 
     Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one having ordinary skill in the art without departing from the scope or spirit of the invention. For example, the pool cover can have as many floats as are necessary to accomplish the functions described above. Moreover, the floats can be positioned in diagonal or other arrangement in addition to, or instead of, along the major and minor axes of the pool cover. The pool cover can be any suitable shape such as circular, oval, quadrangular, triangular, and the like. Accordingly, the invention is not limited by the number and arrangement of the floats or the shapes of the pool cover as illustrated by the embodiments described herein. All variations and modifications are intended to be included within the scope of the invention as defined by the appended claims.