Abstract:
An insulating cover for floating on liquid, such as in a spa, has an area for covering an area of the surface of the liquid. The cover generally comprises a first rectangle for covering a first area and a plurality of successive rectangular tubes connected to either the first rectangle or to a larger rectangle formed by the addition of a prior successive tube so as to form another rectangle for covering additional area. The amount of coverage area can be adjusted by selectively detaching tubes, such as by cutting them off, and by changing the amount of inflation of tubes such that the cover is adaptable to spas of different sizes. In an exemplary embodiment, tubes adjust both the width and length of the cover, and the cover is adapted for folding substantially in half when inflated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 11/400,268 filed Apr. 7, 2006 now U.S. Pat. No. 7,603,727. 
    
    
     FIELD OF THE INVENTION 
     This invention relates in general to insulating covers, and more specifically involves an inflatable, floating spa cover. 
     BACKGROUND OF THE INVENTION 
     Spa covers are used to cover and insulate the spa. The two major types of cover are the rigid cover and the floating cover. The rigid cover commonly is supported by the deck surrounding the spa. Rigid covers are typically about four to six inches thick and contain foam insulation. They are rather heavy and awkward to remove and replace and require a large storage space when off the spa. 
     There are two major types of conventional floating covers. Both types use a large thin sheet of material, typically about one-quarter inch thick, from which is cut a cover to fit the size of the particular spa. One type uses a sheet of closed-cell foam and the other type uses a bubble wrap sheet, such as used in packing. 
     Conventional floating covers of thin sheet material have several drawbacks. They often fold under water when impacted by waterjets of the spa. As a result, they do not cover the entire area and much heat is lost. Also, they must be cut to size, which requires measurement. Additionally, they do not readily provide for solar heating of the spa. 
     Therefore there has been a need for an improved floating spa cover that is inexpensive and readily adaptable to spas of different sizes. 
     It is additionally desirable that such a cover provide solar heating to the spa water. 
     Our above-identified, previously-filed patent describes a circular spa of variable diameter that addresses these concerns with respect to circular spas. However, circular spas vary in size only by varying the diameter, whereas rectangular spas vary in size by varying both length and width such that varying a single dimension does not solve the problem. 
     Particularly in rectangular spas, it is desirable to be able to fold half of the cover back on itself if only half of the spa is being used. Folding the cover back on itself saves the user from having to completely remove the cover and also saves heat energy. 
     Therefore, there has been a need for an improved floating spa cover that is inexpensive and readily adaptable to for rectangular spas of different sizes. It is additionally desirable that such a cover be foldable. It is additionally desirable that such a cover provide solar heating to the spa water. 
     SUMMARY OF THE INVENTION 
     The invention is an insulating cover for floating on liquid, such as in a spa. The cover has an area for covering an area of the surface of the liquid. The cover generally comprises a first rectangle for covering a first area and a plurality of successive rectangular tubes connected to either the first rectangle or to a larger rectangle formed by the addition of a prior successive tube, so as to form another rectangle for covering additional area. The amount of coverage area can be adjusted by selectively detaching tubes, such as by cutting them off, and by changing the amount of inflation of tubes. In this manner, the cover can be adapted to fit in spas of different sizes. 
     In an exemplary embodiment, tubes adjust both the width and length of the cover, and the cover is adapted for folding substantially in half when inflated. 
     Other features and many attendant advantages of the invention will become more apparent upon a reading of the following detailed description together with the drawings wherein like reference numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of an exemplary embodiment of an inflatable, floating spa cover of the invention. 
         FIG. 2  is a partially-cut-away perspective view of a second embodiment of the cover floating on the water of a spa. 
         FIG. 3  is a sectional view of the cover taken on line  3 - 3  of  FIG. 2 . 
         FIG. 4  is an enlarged sectional view of a double weld web of the cover. 
         FIG. 5  is a partially-cut away sectional view showing the cover in the folded position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference now to the drawings, and more particularly to  FIGS. 1-3  thereof, there is shown in  FIG. 1 , a top plan view of an exemplary first embodiment  10 A of an inflatable, floating spa cover  10  of the invention; in  FIG. 2 , a partially-cut-away perspective view of a second embodiment  10 B of the cover  10  floating on the water  90  of a spa  80 , and in  FIG. 3 , a sectional view of cover  10 B taken on line  3 - 3  of  FIG. 1 . 
       FIG. 2  shows a little over half of spa  80  and cover  10 B. Spa  80  generally comprises a receptacle  81  that is substantially rectangular in top view and is defined by side walls  82  including a first pair of spaced, parallel walls  83  (one of which is not shown) and a second pair of spaced, parallel walls  84  for holding water  90  having a surface  92  having an area. Typically, side walls  82  have a top  86  that is above water surface  92  such that water surface  92  is surrounded by a splash wall  85 . Cover  10  floats on surface  92  of water  90  and, preferably, covers all or nearly all of surface  92 . 
     Although the cover  10  of the invention is shown and described with respect to a spa  80  having a splash wall  85 , cover  10  will function on a spill-over type spa wherein the water surface  92  is at the top  86  of side wall  82  and there is no splash wall  85 . Also, although a substantially rectangular spa  80  and cover  10  is shown and described, it will be seen that the teachings of the invention are applicable to spas  80  and covers  10  of other configurations, such as of non-regular geometry. 
     Looking primarily at  FIG. 1 , cover  10 A can be configured into rectangles  20  of various and varying sizes  20 A- 20 H. Cover  10 A generally comprises a main or first rectangle  20 M and one or more independently inflatable and removable adjustment tubes  50 , including adjustment tubes  50 A- 50 H, added thereto to form larger rectangles  20 . Although only one configuration of rectangles  20  is shown in the exemplary embodiment  10 A, it should be understood from the description that other configurations are possible and may be desirable. One principle of the invention is producing a spa cover  10 A of one size, the maximum area of which is reducible by the user by only partially inflating one or more adjustment tubes  50  or by removing one or more adjustment tubes  50 , so as to fit spas  80  of different sizes. Adjustment tubes  50  providing the largest area of coverage that can be fully inflated within side wall  81  of spa  80  are fully inflated and any other still remaining adjustment tubes  50  are partially inflated. 
     Cover  10  is constructed somewhat similar to an air mattress. In the exemplary embodiment, cover  10  is constructed of an upper film  12 , such as of plastic, such as of eight mil thick, ultraviolet light resistant, polyvinylchloride, and a lower film  16 , such as of plastic, such as of twelve mil thick, ultraviolet light resistant polyvinylchloride. Films  12 ,  16  are bonded to one another at bonds  17  to form the major structural components, that is, first rectangle  20 M and adjustment tubes  50 . Preferably, upper film  12  is substantially transparent so as to let sunlight through. Preferably, lower film  16  is translucent such it absorbs some of the light received from upper film  12  and transmits some of the light for directly heating the water. A lower film  16  of blue tint has been found to provide the best heating of the water. The blue film is warmed by sunlight and transmits blue light into the water for heating the water. Upper film  12  and lower film  16  are substantially separated by a gas-filled space, filled such as with air. 
     First rectangle  20 M is buoyant and provides insulation for water  90  and solar heating of water  90 . First rectangle  21  has a periphery  26  surrounding an area for covering a first portion of the area of surface  92  of water  90 . First rectangle  20 M has a first side  22  and a second side  23  opposite first side  22  and separated therefrom in a first direction and a third side  24  and a fourth side  25  opposite third side  24  and separated therefrom in a second direction. 
     In exemplary embodiment  10 A, first rectangle  20 M includes a center section  30  and a pair of stiffener tubes  35 . Center section  30  is of relatively large area, typically constituting far more than half of the area of first rectangle  20 M. In the large center section  30 , means, such as a plurality of bonds  17 , such as ultrasonic or heat and pressure bonds, periodically bond upper film  12  to lower film  16  such that the air space between them is limited in thickness, preferably to about three-quarters of an inch to one inch. Preferably, center section  30  is bonded about its periphery  34  so as to be air tight and is inflatable such as by means of air valve  31 . Center section  30  includes passages  32  therethrough to allow air to escape up from beneath cover  10 A and to allow for water to drain down through from atop cover  10 A. Center section  30  provides the majority of the solar heating to water  90 . 
     One or more stiffener tubes  35  are attached to periphery  34  of center section  30 . In the exemplary embodiment, stiffener tubes  35  are connected to opposite sides of periphery  34 . Preferably, each stiffener tube  35  is independently inflatable, such as by air valves  36 . In the construction, shown, a narrow sealing bond  17 C separates the air space of stiffener tubes  35  from the gas filled space of center section  30 . Stiffener tubes  35  add some stiffness to first rectangle  20 M and help prevent first rectangle  20 M from being swamped or folded under water surface  92  by a water jet of spa  80  and make first rectangle  20 M easier to handle and manipulate. Stiffener tubes  35  could be attached to the other two sides of center section  30 . 
     A plurality of successive adjustment tubes  50  are attached to first rectangle  20 M. Each adjustment tube  50  is rectangular in top view defining an area for covering a portion of the water surface  92 . Each adjustment tube  50  includes an inner side  52  and an outer side  54 . The distance between inner side  52  and outer side  54  defines the width W of adjustment tube  50 . Each adjustment tube  50  includes a first end and a second end, the distance between first end and second end defining the length of tube  50 . Each inner side  52  is connected either to the first rectangle  20 M or to a larger rectangle  20  formed by the addition of a prior successive tube  50  so as to form another rectangle  20 . Each adjustment tube  50  is selectively inflatable, such as by an air valve  51 , independently of first rectangle  20 M and each other adjustment tube  50 . Width W of adjustment tubes  50  depend inversely on the degree of inflation such that the area of said cover is selectively adjustable through a range of water covering areas by adjusting the amount of inflation of adjustment tubes  50 . 
     For example, inner side  52 A of first adjustment tube  50 A is connected to first side  22  of first rectangle  20 M so as to form a second rectangle  20 A therewith in top view, the second rectangle having a first side, a second side, a third side, and a fourth side. Preferably, the area of first adjustment tube  50 A is less than twenty percent of area of area of first rectangle  20 M. 
     Inner side  52 B of second adjustment tube  50 B is connected to the second rectangle  20 A, such as to first side of second rectangle  20 A opposite first adjustment tube  50 A so as to form a third rectangle  20 B therewith in top view. Second adjustment tube  50 B has a length corresponding to the side of second rectangle  20 A to which it is attached. Preferably, the area of second tube  50 B is less than twenty percent of the area of second rectangle  20 A. 
     Successive adjustment tubes  50 C- 50 F are attached in a similar manner in the first direction to form larger rectangles  20 C- 20 F. 
     Adjustment tube  50 G is attached to rectangle  20 B in the second direction to form rectangle  20 G. Alternatively, tube  50 G could be attached to rectangle  20 C to substantially form larger rectangle  20 G′, attached to rectangle  20 D to substantially form larger rectangle  20 G″, attached to rectangle  20 E to substantially form larger rectangle  20 G′″, or attached to rectangle  20 F to substantially form larger rectangle  20 G″″. The descriptor “substantially” is used to denote that the corner area of the rectangle formed is not completely filled in. 
     Successive adjustment tube  50 H is attached to rectangle  20 D in the second direction to form rectangle  20 H. Alternatively, tube  50 H could be attached to rectangle  20 E to substantially form larger rectangle  20 H′, attached to rectangle  20 F to substantially form rectangle  20 H″, attached to rectangle  20 G″ to substantially form rectangle  20 H′″, attached to rectangle  20 G′″ to substantially form rectangle  20 H″″ or attached to rectangle  200 ″″ to substantially form rectangle  20 H′″″ which includes all of the tubes  50  shown. 
     Although, in the exemplary embodiment, the length of tubes  50 G and  50 H are shown to be the length of rectangle  20 D in the first direction, it should be understood that the lengths could conform to the length of one of the smaller or larger rectangles  20   
     Looking again at  FIGS. 2 and 3 , cover  10 B is cover  10 A trimmed to fit within side wall  81  by removing tubes  50 E and  50 F to form rectangle  20 H. Tubes  50 G and  50 H are only partially inflated to make them wider so as to just fit within first pair  82  of side wall  81 . 
       FIG. 4  is an enlarged view of area  4  of  FIG. 3  showing a web  60  of cover  10  and specifically a double weld web  60 D. Each adjustment tube  50  is connected to the preceding rectangle so as to be easily selectively removable therefrom. Preferably a wide web  60  is used for attachment. Upper film  12  may be bonded to lower film  16  over the whole width of web  60  or, preferably, as double bonds  17 D, that is a bonds  17  along each outer side of web  60  leaving a loose and unattached section of upper film  12  and lower film  16  between bonds  17 D. The unattached section between bonds  17 D is easily cut with a blade or scissors. If the wide web  60  is bonded over its entire width it tends to be stiff and is not as easily cut. 
       FIG. 5  is a partially-cut away sectional view showing cover  10  in the folded position. Cover  10  includes a center hinge  70  for folding cover  10  substantially in half when cover  10  is inflated. This allows a user to use half of spa  80  while the other half remains covered or provides for a more compact cover  10  for removal and storage while spa  80  is in use. 
     Center hinge  70  is a wide web  60  across cover  10  from side to side at or near the midsection and may include a series of webs  60  separated to provide a small passage for inflation air to pass to the other half of an enclosure. Center hinge  70  may be bonded over its entire area or may include double bonds  17 D or more separated bonds as desired. 
     Having described the invention, it can be seen that it provides for a very efficient spa cover that is adaptable for rectangular spas of various sizes. 
     Although a particular embodiment of the invention has been illustrated and described, various changes may be made in the form, composition, construction, and arrangement of the parts herein without sacrificing any of its advantages. Therefore, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense, and it is intended to cover in the appended claims such modifications as come within the true spirit and scope of the invention