Spa Cover

Abstract

A spa cover is described, and which includes first and second fluid impermeable portions which are individually mounted on a spa, and are further independently moveable, one relative to the other, and wherein the respective first and second fluid impermeable portions each have moveable first and second sections, and wherein the spa cover is fabricated in the nature of a bi-fold.

Description

TECHNICAL FIELD

The present invention relates to a spa cover, and more specifically to a fluid impermeable spa cover which avoids many of the detriments associated with the prior art devices utilized heretofore.

BACKGROUND OF THE INVENTION

Covers for spas or so-called “hot tubs” have been utilized for decades. These covers are often employed in cooler climates to minimize the escape of heat energy from the spa. Further, they are often employed to cover the spa to prevent unauthorized access to the spa, or to prevent debris such as dust, leaves, insects and the like from being deposited within the hot tub. Heretofore, spa covers have had two portions which have usually been fabricated from lightweight, insulative sheets which have been typically enclosed in a flexible synthetic sheet or envelope. The two portions are typically joined together by a hinge. In most prior art covers the hinge is formed by a seam of flexible material which bridges between the two halves or portions. It has been common practice to remove such prior art spa covers by swinging or moving one-half of the cover onto the remaining other half, and then lifting both of the halves off of the top of the spa. As is described in various detail in many prior art references, this task of removing a spa cover has sometimes been difficult because of the awkwardness, of the spa cover construction, and further due to the weight of the spa covers as these same spa covers have become heavier, over time, due to the absorption of water which is occasioned by their proximity to the underlying heated spa, or because water is absorbed from the ambient environment.

Many references have noted that spa owners have long understood that spa covers having the prior art construction must be periodically replaced because such spa covers, over time, become water logged, and thereafter become too difficult and heavy to handle and further lose some of their insulative characteristics. Further these waterlogged spa covers encourage the growth of mold, mildew and other undesirable organisms. As is reported in many prior art references, these previous prior art spa covers often deteriorate over time because they often are directly exposed to the ambient environment. Therefore sunlight and other environmental conditions such as high and low temperatures rapidly deteriorate or weaken the construction of the spa covers such that they must be periodically replaced, for example, every three to five years. Because these prior art spa covers are replaced on a rather frequent basis, the manufacturers of same have endeavored to keep the cost of manufacturing such covers to a minimum. However, the motivation to keep the price point of such products at a level that encourages the periodic purchase and replacement of a spa cover does not motivate the manufacturers to use high quality materials, which will resist the aforementioned environmental degradation or the absorption of water, which is occasioned by the proximity of the spa cover to the underlying heated water enclosed within the spa.

To address these and other shortcomings, the present inventor developed and is currently marketing a spa cover similar to that shown in U.S. Pat. No. 8,813,275, and which issued on Aug. 26, 2014. The aforementioned spa cover, which is described, includes first and second rigid portions which are joined together by a continuous hinge. This patent further describes a multiplicity of spaced uniformly elongated internal channels extending between the opposite peripheral edges thereof. In this design, individual lightweight, unitary, insulative inserts are dimensioned for telescoping receipt within each of the internal channels which are defined by the respective first and second portions. The first and second portions are moveable together, along a hinge, so as to be removable from the spa but further are rigid enough so as to allow a user to stand on the spa cover to remove snow and the like, and which further are resistant to the absorption of water. The aforementioned spa cover has found great success, especially in geographical areas where large amounts of snow fall is experienced, or which further might be subject to harsher ambient environmental conditions.

While the foregoing spa cover, seen in U.S. Pat. No. 8,813,275, has worked with a great deal of success, and has experienced widespread market acceptance, the utilization of such spa covers on relatively large spas has presented some difficulties inasmuch as the construction employed in such spa covers tends to make the two portions of the spa cover, as disclosed, somewhat heavier and difficult to move by individuals having reduced strength or under certain environmental conditions, such as in windy conditions, or when the spa cover might be partially covered with snow, ice, or the like.

A spa cover which avoids the detriments associated with the prior art devices and practices utilized heretofore is the subject matter of the present application.

SUMMARY OF THE INVENTION

A first aspect of the present invention relates to a spa cover, which includes a first and second fluid impermeable portion which are individually mounted on a spa, and which are further independently moveable, one relative to the other, and wherein the respective first and second fluid impermeable portions each have moveable first and second sections, and wherein the spa cover is arranged in the nature of a bi-fold.

A second aspect of the present invention relates to a spa cover which includes a first and a second rigid, fluid impermeable portion, and which are independently moveably mounted on a spa, and wherein the spa has opposite sides, and a top peripheral edge, and wherein the respective fluid impermeable portions each have a first and second section which are hingedly mounted together, and are further moveable one relative to the other, and wherein the respective first and second sections of each of the fluid impermeable portions, when oriented in a coplanar orientation, rest on the top peripheral edge of the spa, and are effective, in combination, to cover the spa, and wherein the respective first sections of each of the fluid impermeable portions are operable to move along an arcuately shaped path of travel from a first, coplanar orientation relative to the adjacent hingedly attached second section, to a second position, and wherein, in the second position, the first section is oriented in substantially parallel relation relative to the second section, and a portion of the spa is uncovered, and wherein the respective first and second sections are moveable, in unison, from the second position to a third position, and wherein in the third position, the respective first and second fluid impermeable portions are located in an orientation where the spa is completely uncovered.

These and other aspects of the present invention will be described in greater detail hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below with reference to the following accompanying drawings.

FIG. 1 is a perspective, side elevation view showing the new spa cover positioned in covering relation relative to a spa of traditional design.

FIG. 2 is a perspective, side elevation view of the spa cover of the present invention and which is shown while being moved to an open position.

FIG. 3 depicts the spa cover of the prevent invention shown in an orientation where the spa cover partially covers the underlying spa.

FIG. 4 is a perspective, side elevation view which shows the spa cover of the present invention when it is located in an orientation where it does not cover the underlying spa.

FIG. 5 is a fragmentary, partial, side elevation view of a hinge which forms a feature of the present invention.

FIG. 6 is a greatly simplified, transverse, vertical sectional view taken through a portion of the spa cover of the present invention.

FIG. 7 is a greatly simplified, exploded, fragmentary side elevation view of a hollow synthetic board which forms a feature of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent laws to promote the progress of science in useful arts. [Article I, Section 8]

An example of a spa cover incorporating the features of the present invention is generally indicated by the numeral 10 in FIG. 1, and following. As seen in FIG. 1, the spa cover 10 is operable to cooperate with a spa 11 of traditional design. The spa is defined, in part, by a circumscribing sidewall, which is generally indicated by the numeral 12. The sidewall 12 has an outside facing surface 13, and an opposite, inside facing surface 14. Still further, the circumscribing sidewall 12 has a top peripheral edge 15, which defines an opening 16, and which further allows access to the internal cavity of the spa 20. The internal cavity, of course, encloses a body of heated water for the enjoyment of the spa owner. The circumscribing sidewall 12 has a first side or end 21, and an opposite side or end which is generally indicated by the numeral 22.

The spa cover 10 of the present invention includes a pair of substantially fluid impermeable portions which are generally indicated by the numeral 30. The pair of fluid impermeable portions includes a first fluid impermeable portion 31, and a second fluid impermeable portion 32. The first and second fluid impermeable portions are individually mounted on the spa 11, and are further independently moveable, one relative to the other. As seen in the drawings, the respective first and second fluid impermeable portions each have moveable first and second sections, as will be described below, and wherein the spa cover 10 operates in the manner of a bi-fold. In this regard, the first fluid impermeable portion 31 has a first and second section 33 and 34, respectively, and which are hingedly mounted together so as to facilitate the movement of the first section 33 relative to the second section 34, as will be described hereinafter. Similarly, the second fluid impermeable portion 32 has a first and second section, 35 and 36 respectively, and which are, again, hingedly mounted together so as to facilitate the movement of the first section 35 relative to the second section 36.

The respective first and second sections 33 through 36, which form the first and second fluid impermeable portions 31 and 32, are each formed from a plurality of rigid tongue and groove shaped synthetic boards 40, which are affixed together so as to provide an upwardly facing supporting surface 41, and which further can support a weight of greater than 100 pounds per square foot without permanently deflecting and/or distorting the first and second section 33 through 36, respectively, during use. The plurality of rigid synthetic boards 40, when formed into the individual first and second sections 33 through 36, respectively, also define a downwardly facing surface 42, which is operable to engage and otherwise rest in supported relation on the top peripheral edge 15 of the spa 11. The respective hollow, tongue and groove synthetic boards have opposite ends 43, and which allow access to an internal cavity 44. Additionally, and as will be seen in the drawings, a sealing member 45 is affixed to the downwardly facing surface 42, and is operable to sealingly engage the top peripheral edge 15, of the spa 11, when the respective first and second sections 33-36, respectively, are disposed in a substantially co-planar orientation, one relative to the others, and in a covering or occluding relation relative to the opening 16, which is defined by the circumscribing sidewall 12 of the spa 11.

Referring now to FIG. 7, it will be understood that the present invention includes an insulative material which is generally indicated by the numeral 50, and which is further inserted or deposited within the internal cavity 44, as defined by the respective plurality of rigid tongue and groove shaped, synthetic boards 40. As seen in the drawings, the insulative material 50 is shown as a pre-formed insert. This insert could be fabricated, for example, from a closed pore insulation, which is resistant to the absorption of water, or further could be fabricated from other insulative material, which might first be injected, and then later solidify within the internal cavity 44. The insulative material 50 is designed to substantially fill all the space within the internal cavity 44, so as to prevent the accumulation of moisture, and to further impede the loss of heat energy from the underlying spa 11 which is in operation. As seen in the drawings, the insulative material 50 is received through one of the open ends 43 of the respective rigid tongue and groove synthetic boards 40. Further, and as seen in the drawings, a peripheral edge cover 51 is provided, and which engages the end 43 of the respective synthetic boards, thereby sealing the insulative material 50 within each of the internal cavities 44. The peripheral edge covers further provide an additional advantage inasmuch as the edge covers may be periodically removed so as to allow a spa owner to remove the insulative material 50 in the event that the insulative material becomes partially or wholly ineffective by becoming water-logged, or some other failure of the insulated material becomes evident. As seen in FIG. 5, the first and second sections 33 and 34 of the first fluid impermeable portion 31 are shown in a partial, vertical sectional view. In this view it will be seen that the first and second sections 33 and 34; and the first and second sections 35 and 36, are each hingedly mounted together by a continuous hinge, which is generally indicated by the numeral 60. The hinge 60, and its operation, will be discussed in the paragraphs that follow.

The first and second sections 33-36, respectively, of the first and second fluid impermeable portions 31 and 32, as noted above, are hingedly mounted together so as to facilitate the movement of the first section 33 or 35, relative to the second sections 32 and 36, respectively, along a pair of arcuately shaped paths of travel (only one of which is shown) and which is indicated by the numeral 70 in FIG. 2. As seen by a comparison of FIGS. 2 and 3, and with regard to the first fluid impermeable portion 31, the first section 33 is moveable from a first position 71, and where the first section 33 is positioned in a co-planar orientation relative to the second section 34; to a second position which is generally indicated by the numeral 72. In the second position 72, the first section 33 is located in a parallel, juxtaposed relationship relative to the second section 34. This is seen most clearly by reference to FIG. 3. In the second position 72, the spa opening 16 is partially non-occluded. Further, the first and second sections 33 and 34 are moveable, in unison, from the second position 72, to a third position 83, and along a second path of travel which is generally indicated by the numeral 80. When located in the third position 83 [FIG. 4], the first and second sections 33-36 are removed from the peripheral edge 15, and the spa opening 16 is completely non-occluded. With regard to the movement of the first and second sections 33-36 relative to each other, it should be understood that the sizes and weights of the first sections 33 and 35 are selected so that the amount of force required by a spa owner to move the first section 33 and 35 into a parallel relationship relative to the second section 34 and 36 is equal to or less than the amount of force required for the two sections 33 and 34 and 35 and 36 to be moved in unison from the second position 72, to the third position 83. This is accomplished by means of the mechanical advantage provided by the spa lift 90, which will be discussed, below.

The first and second sections, for example, 33 and 34, of the first fluid impermeable portion 31, are moveable from the second position 72, to the third position 83, by way of a spa lift, and which is generally indicated by the numeral 90. The spa lift 90 includes a first portion 91, which is received within, and extends through, one of the internal cavities 44, as defined by one of the hollow, synthetic boards, and which is located adjacent to the hinge 60, and which further moveably couples the first and second sections 33 and 34, for example, together. The spa lift 90 includes a second portion 92, which includes a pair of elongated supports 93, and which are individually positioned in an exterior relationship relative to the plurality of synthetic boards 40 and which form the respective fluid impermeable portion 31 and 32, respectively. The respective elongated supports 93 are each coupled to the first portion of the spa lift 91. Further, each of the elongated supports 93 has a distal end 94, and which is mounted on the side wall 12, defining the spa 11. The second portion 92 of the spa lift facilitates the movement of the first and second sections 33 and 34 (for example) of the spa cover 10 in unison, and along the path of travel 80 from the second position 72, to the third position 83, and which results in an exposure of the spa 11. In the arrangement as seen in the drawings, the spa cover 10 has an insulative spa rating of 8 or greater.

Operation

The operation of the described embodiment of the present invention is believed to be readily apparent, and is briefly summarized at this point. In its broadest aspect, the present invention relates to a spa cover 10, which includes a first and second fluid impermeable portion 31 and 32, respectively, and which are individually mounted on a spa 11. The first and second fluid impermeable portions 31 and 32 are independently moveable, one relative to the other. Further, the respective first and second fluid impermeable portions 31 and 32, respectively, each have a moveable first and second section 33 through 36, and wherein the spa cover 10 is fabricated and operates in the nature of a bi-fold.

In the arrangement as seen in the drawings, the first and second fluid impermeable portions 31 and 32, respectively, are mounted on, and are independently moveable relative to the opposite sides 21 and 22 of the circumscribing sidewall 12, and which defines the spa 11. In the arrangement as seen in the drawings, the first and second sections 33 through 36 of each of the fluid impermeable portions 31 and 32, respectively, are hingedly mounted together. The spa cover 10 operates in the nature of a bi-fold, and further facilitates the movement of the first sections 33 and 35, relative to the second sections 34 and 36, along a pair of arcuately shaped paths of travel 70. In this arrangement, the first sections 33 and 35 are moveable from a first position 71, and where the first sections 33 and 35, respectively, are positioned in a co-planar orientation relative to the associated second sections 34 and 36, respectively; and to a second position 72. In the second position 72, the first sections 33 and 35 are located in parallel, juxtaposed relation relative to the second sections 34 and 36. in its arrangement and when the first and second sections 33 through 36 are juxtaposed or oriented in substantially parallel relation, one relative to the other, the spa opening 16 is partially non-occluded (FIG. 3). Still further, the first and second sections 33 to 36 are moveable, in unison, from the second position 72, to a third position 83. In the third position 83, the first and second sections 33 to 36 are removed from the peripheral edge 15, and the spa opening 16 is completely non-occluded (FIG. 4).

In the present invention, the respective first and second sections 33 to 36 of each of the fluid impermeable portions 31 and 32 are fabricated from a plurality of rigid tongue and groove shaped, hollow synthetic and fluid impermeable boards 40, which are affixed together so as to provide an upwardly facing supporting surface 41, and which further can support a weight of greater than about 100 pounds per square foot without permanently deflecting and distorting the first and second sections 33 to 36, respectively. As seen in the drawings, an insulative material 50 is inserted within, and completely fills, the respective hollow fluid impermeable synthetic tongue and groove shaped boards 40. The insulative material which is selected resists the absorption of water. In the arrangement as seen in the drawings, the first and second fluid impermeable portions 31 and 32, each have a downwardly facing spa engaging surface 42, and wherein a sealing member 45 is provided, and is further mounted on the downwardly facing spa engaging surface. The sealing members 45 sealably engages the peripheral edge 15, which is defined by the sidewall 12 of the spa 11.

More specifically, the present invention relates to a spa cover 10 which includes a first and second rigid fluid impermeable portions 31 and 32, respectively, and which are independently moveably mounted on a spa 11. The spa 11 with which the spa cover 10 cooperates, has opposite sides 21 and 22, and a top peripheral edge 15. The respective fluid impermeable portions 31 and 32 each have a first and second section 33 to 36, which are hingedly mounted together, and which are further moveable, one relative to the other. The respective first and second sections 33 to 36 of each of the fluid impermeable portions 31 and 32, respectively, when oriented in a co-planar orientation, rest on the top peripheral edge 15 of the spa 11, and are effective, in combination, to cover or occlude the spa 11. The respective first sections 33 and 35 of each of the fluid impermeable portions 31 and 32, respectively, are operable to move along an arcuately shaped path of travel 70, from a first co-planar orientation 71, relative to the adjacent, hingedly attached second portion 34 and 36, respectively; to a second position 72. In the second position 72, the first sections 33 and 35, respectively, are oriented in substantially parallel relation relative to the respective second sections 34 and 36, respectively, and a portion of the spa 11 is uncovered (FIG. 3). The respective first and second sections 33 and 36, for example, are moveable in unison from the second position 72 to a third position 83. In the third position 83, the respective first and second fluid impermeable portions 32 to 36 are located in an orientation where the spa 11 is completely uncovered.

In the arrangement as seen in the drawings, the first and second sections 33 to 36, and which form the fluid impermeable portions 31 and 32, have a predetermined width dimension, and wherein the width dimension of the respective first and second sections 33 through 36 are substantially equal. Still further, in another alternative form of the invention, each of the respective first and second sections 33 to 36 have an unequal width dimension. Further, in one possible form of the invention, the first and second sections 33 to 36, of each of the respective fluid impermeable portions 31 and 32, have a similar weight. However, in another alternative form of the invention, the first and second sections of each of the respective fluid impermeable portions 31 and 32 have a dissimilar weight. Again, as earlier discussed, the amount of force a user must apply to move the first sections 33 and 35 relative to the associated second sections 34 and 36, respectively, is equal to or less than the amount of force required to move the first and second sections 33 to 36, when located in the second position 72, to the third position 83. This is due to the mechanical advantage as provided by the spa lift 90, and which facilitates the movement of the spa cover 70 from the second position 72 to the third position 83, and wherein the spa 11 is completely uncovered.

Therefore, it will be seen that the present invention provides a convenient means for a spa owner to conveniently cover a spa with a spa cover, and which further provides many advantages over the prior art products which have been fabricated and utilized heretofore, The present spa cover provides a rigid supporting surface, which can support snow loads, and further can support the weight of a user, should a user need to stand on the spa cover for purposes of removing snow and the like. The present spa cover further provides other advantages inasmuch as it is fluid impermeable and provides a desirable insulative effect which reduces the cost of maintaining a spa at an operable temperature in various climates.

In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the Doctrine of Equivalence.

Claims

1. A spa cover comprising:

a first and second fluid impermeable portion which are individually mounted on a spa, and which are further independently moveable, one relative to the other, and wherein the respective first and second fluid impermeable portions each have moveable first and second sections, and the spa cover is arranged in the nature of a bi-fold.

2. A spa cover as claimed in claim 1, and wherein the spa has a main body which has a circumscribing sidewall having opposite sides, and wherein the sidewall has an upwardly facing peripheral edge which defines, at least in part, an opening, and which communicates with an internal cavity that is defined by the sidewall, and wherein the respective first and second fluid impermeable portions when positioned in a coplanar orientation, one relative to the other occludes the opening defined by the upwardly facing peripheral edge.

3. A spa cover as claimed in claim 2, and wherein the first and second fluid impermeable portions are mounted on, and moveable relative to, the opposite sides of the circumscribing sidewall.

4. A spa cover as claimed in claim 3, and wherein the first and second sections of each of the fluid impermeable portions are hingedly mounted together so as to facilitate the movement of the first section, relative to the second section, along an arcuately shaped path of travel, and wherein the first section, is moveable from a first position where the first section is positioned in a coplanar orientation relative to the second section, to a second position, and wherein in the second position, the first section is located in parallel, juxtaposed relation relative to the second section, and wherein, when the first and second sections are oriented in juxtaposed, substantially parallel relation, the spa opening is partially non-occluded, and wherein the first and second sections are further moveable, in unison, from the second position, to a third position, and wherein in the third position the first and second sections are removed from the peripheral edge, and the spa opening in completely non-occluded.

5. A spa cover as claimed in claim 4, and wherein the respective first and second sections of each of the fluid impermeable portions are fabricated from a plurality of rigid, tongue and groove shaped, hollow, synthetic and fluid impermeable boards which are affixed together so as to provide an upwardly facing supporting surface which can support a weight greater than about 100 pounds per square foot without permanently deflecting and distorting the first and second sections.

6. A spa cover as claimed in claim 5, and wherein an insulative material is inserted within, and completely fills the respective hollow, fluid impermeable synthetic tongue and groove boards, and wherein the insulative material resists the absorption of water.

7. A spa cover as claimed in claim 6, and wherein each of the plurality of rigid, tongue and groove shaped, hollow, synthetic boards have opposite ends, and wherein at least one of the ends of each of the hollow, synthetic boards defines an opening which permits access to an internal cavity which is defined by the respective hollow synthetic boards, and wherein a peripheral edge cover engages at least one of the opposite ends of the respective hollow synthetic boards, and occludes the opening defined by the hollow synthetic board, and maintains the insulative material within the hollow synthetic board.

8. A spa cover as claimed in claim 7, and wherein a continuous hinge moveably couples the first and second sections of each of the first and second fluid impermeable portions together, and which further facilitates the movement of the first section relative to the second section.

9. A spa cover as claimed in claim 8, and wherein the first and second sections are moveable from the second position to the third position by way of a spa lift, and wherein the spa lift includes a first portion which is received within, and extends through, one of the internal cavities of one of the hollow synthetic boards, and which is located adjacent to the continuous hinge which moveably couples the first and second sections together, and wherein the spa lift includes a second portion, which includes a pair of elongated supports, and wherein the respective elongated supports are each coupled to the first portion, and wherein each of the elongated supports further has a distal end which is mounted on the sidewall defining the spa, and wherein the second portion of the spa lift facilitates the movement of the first and second sections, in unison, along a path of travel from the second position, and to the third position, and which exposes the spa for use.

10. A spa cover as claimed in claim 9, and wherein the spa cover has an insulative spa rating of 8 or greater.

11. A spa cover as claimed in claim 10, and wherein the respective first and second fluid impermeable portions each have a downwardly facing spa engaging surface, and wherein a sealing member is mounted on the downwardly facing spa engaging surface, and which sealably engages the peripheral edge that is defined by the sidewall.

12. A spa cover comprising:

a first and a second rigid, fluid impermeable portion, and which are further independently moveably mounted on a spa, and wherein the spa has opposite sides, and a top peripheral edge, and wherein the respective fluid impermeable portions each have a first and second section which are hingedly mounted together, and are further moveable one relative to the other, and wherein the respective first and second sections of each of the fluid impermeable portions, when oriented in a coplanar orientation, rest on the top peripheral edge of the spa, and are effective, in combination, to cover the spa, and wherein the respective first sections of each of the fluid impermeable portions are operable to move along an arcuately shaped path of travel from a first, co-planar orientation relative to the adjacent hingedly attached second section, to a second position, and wherein, in the second position, the first section is oriented in substantially parallel relation relative to the second section, and a portion of the spa is uncovered, and wherein the respective first and second sections are moveable, in unison, from the second position to a third position, and wherein in the third position, the respective first and second fluid impermeable portions are located in an orientation where the spa is completely uncovered.

13. A spa cover as claimed in claim 12, and wherein the spa is defined by a circumscribing sidewall which has opposite sides, and wherein a spa lift is mounted on each of the opposite sides of the spa, and which moveably engage the respective first and second fluid impermeable portions so as to facilitate the selective uncovering of the spa.

14. A spa cover as claimed in claim 13, and wherein the first and second sections of each of the respective fluid impermeable portions have a predetermined width dimension, and wherein the width dimension of the respective first and second sections are substantially equal

15. A spa cover as claimed in claim 13, and wherein the first and second sections of each of the respective fluid impermeable portions have a predetermined width dimension, and wherein the width dimensions of the respective first and second sections are unequal.

16. A spa cover as claimed in claim 13, and wherein the first and second sections of each of the respective fluid impermeable portions have a similar weight.

17. A spa cover as claimed in claim 13, and wherein the first and second sections of each of the respective fluid impermeable portions have a dissimilar weight.