This invention relates to swimming pool covers.

Swimming pool covers are used in conjunction with swimming pools for various purposes, namely to prevent and/or inhibit people, animals, debris and other objects from falling into the pool when it is not in use. Swimming pool covers are also used for thermal insulation, i.e. to reduce heat loss from the water of the swimming pool when it is not in use. In other situations, swimming pool covers are used to prevent loss of water from the swimming pool. The latter use of a swimming pool cover is particularly pertinent on cruise ships and the like, where in stormy weather, it is often necessary to partially, or completely, empty the swimming pool to avoid its contents from sloshing out onto the decks of the vessel and/or to preserve the stability of the vessel itself in stormy conditions.

Various known swimming pool covers are available and these fall into several different categories. The first type is a flexible, usually plastics, cover which is rolled up when not in use, but which can be unrolled and laid on top of the swimming pool water surface when the cover is needed. A roll-up swimming pool cover is typically manufactured from a buoyant material (e.g. polymer foam) such that it floats on the water’s surface and comprises anchoring means, for example eyelets which can be used to secure the swimming pool cover in position and thereby prevent it from being blown away. The securement also to provides some security against heavy objects falling on the cover. This type of swimming pool cover has been found to be largely ineffective for the purpose of protecting people from drowning because if a heavy object lands on the swimming pool cover, it can sink into the water and wrap the person in the cover thereby making it more difficult for the person to escape from the pool.

In order to overcome this shortcoming, other known swimming pool covers are manufactured of hard material, such as metal or plastic slats, which can be pulled out over the swimming pool when it is not in use. The use of a "roller shutter" type arrangement has the advantage of providing a more rigid surface over the pool and, where the slats are structural, provides a rigid span over the pool which can be walked upon, or which at least is able to support the weight of a person who inadvertently, or deliberately, walks over the cover. Roller shutter type swimming pool covers are difficult to store due to their bulk and weight and do not, in any event, prevent or inhibit the loss of water from the swimming pool because there is no seal between the cover and the edges of the pool.

In the special situation outlined above, mainly on a cruise ship or the like having a swimming pool, the use of flexible sheet and roller shutter type swimming pool covers is impractical for various reasons. Firstly, when the ship is moving through heavy seas, its decks will move around considerably and this, therefore, increases the likelihood that a person or object may fall onto the swimming pool cover. As such, a ship's swimming pool cover needs to be proof against such occurrences. Furthermore, because known swimming pool covers do not seal-in the water of the swimming pool, this can lead to sloshing of the swimming pool water thereby leading to instability of the vessel itself and also loss of water over the decks, which can wash nearby people off their feet in certain circumstances. Moreover, the weight and bulk of a roller shutter type swimming pool cover is contraindicated for ship-based applications. Furthermore, when a swimming pool is out of operation, there is a large amount of redundant deck space, which cannot be used for other purposes. A need therefore exists for a solution to one or more of the above problems, which this invention aims to provide.

On a cruise ship or other boat equipped with a swimming pool, in rough seas, it has become customary practice to drain the swimming pool for safety purposes - as shall be appreciated from the foregoing. Flowever, the cost of emptying and refilling (and optionally reheating the water within the pool) is very high and the draining/refilling process is time-consuming. When the pool has been emptied, there is, effectively, an empty void in the deck, which presents a fall hazard to occupants of the vessel and when the pool has been emptied, the entire pool area is effectively out of use.

This invention aims to provide a solution to one or more of the above problems and/or to provide an improved and/or alternative type of swimming pool cover. Aspects of the invention are set forth in the appended independent claims. Preferred and/or optional features of the invention are set forth in the appended dependent claims.

According to a first aspect of the invention, there is provided a swimming pool cover comprising a main body portion and a periphery extending around one or more edges of the main body portion, the main body portion and periphery being integrally-formed inflatable structures, in which the main body portion comprises a drop-stitch structure and the periphery comprises an air cell structure.

The shape and/or dimensions of the swimming pool cover of the invention are suitably adapted to fit the shape of the swimming pool which it is to be fitted. Preferably, the overall width of the swimming pool cover is slightly wider than the overall width of the swimming pool, and the overall length of the swimming pool cover is slightly greater than the overall length of the swimming pool. By slightly over-sizing the swimming pool cover, it can be placed onto the swimming pool water's surface and inflated so that the main body covers the majority of the swimming pool water's surface and the air cell periphery engages the side walls of the swimming pool. Because the swimming pool cover is preferably slightly over-sized, further inflation of the swimming pool cover causes the air cell periphery to positively engage with the side walls of the swimming pool thereby, effectively, clamping the swimming pool cover in position.

The use of an air cell periphery to the swimming pool cover means that the edges of the swimming pool cover can conform to the shape and certain irregularities in the side walls of the swimming pool itself. For example, where there are light fittings, drainage apertures, ladders and other fittings located on the side walls of the swimming pool, the air cell periphery of the swimming pool cover is able to conform to these and nevertheless grip the side walls of the swimming pool to retain the cover in position.

The main body of the swimming pool cover is manufactured from a drop-stitch structure, that is to say having upper and lower skins, which are interconnected, at intervals, by "space yarns". A space yarn is a flexible, but substantially inextensible, or inextensible, cord, which interconnects the opposing inner surfaces of the swimming pool cover, which means that when the main body is inflated, the space yarns become taut - thereby maintaining the upper and lower walls of the swimming pool cover relative positions defined by the lengths of the space yarns between them.

In one embodiment of the invention, the space yarns are approximately the same length, which means that the upper and lower surfaces of the main body are substantially parallel. This creates a flat upper and lower surface of the main body, which may be useful as an additional decking area spanning the pool when the pool is not in use.

In other embodiments of the invention, the lengths of the space yarns are unequal. For example, the length of the space yarns at, or towards, the centre of the main body could be slightly longer than those at, or towards, the edges of the main body - so as to produce a sloping or cambered upper surface, which may be useful for shedding rainwater and the like from the pool cover.

It will be appreciated, by the skilled reader, that a drop-stitch structure when inflated, provides a rigid, hard surface, which can be used as a walkway - unlike an air cell structure, which is generally flexible even when inflated to relatively high pressures. As such, the upper surface of the swimming pool cover can be used as a walkway surface thereby increasing the amount of available deck space on the vessel.

The air cell periphery extending around the sides of the main body preferably extends all the way around the main body so as to provide an air cell structure surrounding the periphery of the main body. This means that the pool cover can grip onto all sides of the swimming pool when it is in use.

In other situations, for example, where the swimming pool cover is fitted to an "infinity" pool

(e.g. where the water level is at the top of the pool structure and forms a waterfall at one end), the swimming pool cover may be fitted with a drop-stitch extension part, which projects beyond the water surface, and which has a return from which an air cell part extends back towards the end wall of the swimming pool structure. Thereby, upon inflation, the drop-stitch part forms a rigid structure, and the air cell parts inflate to form seals against the inner walls of the swimming pool structure, or against an outer wall of the swimming pool structure, as the case may be. The conforming nature of the air cell periphery can lead to the formation of a seal between the pool cover and the side walls of the swimming pool. This is particularly beneficial on cruise ships and the like, where it is necessary or desirable to contain or seal the water within the swimming pool.

In certain embodiments of the invention, for example, where the swimming pool has an inwardly-directed lip overhanging the side walls of the swimming pool, it may be possible to inflate the swimming pool cover so that it loosely engages the side walls of the swimming pool Then, additional water can be added to the swimming pool so as to raise the swimming pool cover so that its air cell peripheries begin to engage with the undersides of the inwardly-directed lips of the swimming pool itself. Then, full inflation of the swimming pool cover can be completed to fully-engage the air cell periphery with the side walls of the swimming pool, as well as the underside of the inwardly-directed lips of the swimming pool, to lock the cover in position.

In this situation, the engagement of the air cell periphery with the side walls and lip of the swimming pool, in combination with the upward pressure of the slightly over-filled swimming pool below gives rise to an extremely rigid, evenly and well-supported, and well-engaged cover.

It will be appreciated that because the swimming pool cover is inflatable, it will float on the water's surface. This means that the structural requirements of the drop-stitch main body portion are reduced somewhat insofar as there is no need for the drop-stitch main body to structurally "span" the width of the pool because it is supported, by buoyancy, across its entire under surface.

It will be appreciated that where the swimming pool cover is to be used as an additional decking area, that additional protection may be required to render it proof against punctures. For example, people wearing high heels should not walk over an inflatable structure because this could lead to punctures. However, the invention proposes to incorporate, or provide, a hard, upper skin or surface to the main body, in certain embodiments. This could be by way of a set of boards, which can be overlaid over the swimming pool cover, when it has been deployed, or the hard surface could be incorporated into the upper surface of the main body itself. In certain situations, the boards may be, or comprise, photovoltaic panels, which generate electrical power, which can be used to power an inflation pump for the swimming pool structure and/or a heater/cooler for the water within the swimming pool.

Preferably, the swimming pool cover comprises an air pressure sensor, which senses the air pressure within the swimming pool cover. Suitably, upon detection of deflation, i.e. the air pressure falling below a specified value, the swimming pool cover can be adapted to automatically re-inflate, or top-up its internal pressure, which may help to, or ensure, that, a minimum inflation pressure is maintained.

In order to meet the safety standards in various parts of the world, additional securement means, such as straps, may be provided to enable the swimming pool cover to be secured to a structure surrounding the swimming pool.

In order to facilitate storage of the structure, where a hard, upper surface or skin is provided, this suitably comprises a slatted or tiled structure, which permits the pool cover to be folded and/or rolled when it is not in use.

Preferred embodiments in the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic, perspective, partially cut-away view of a swimming pool cover in accordance with the invention;

Figure 2 is a partial cross-section of Figure 1 on ll-ll;

Figure 3 is a first possible schematic cross-sectional view of the swimming pool cover of Figure 1, in use;

Figure 4 shows a variation of the swimming pool cover of Figure 3 fitted to an "infinity" pool; and

Figure 5 is a second possible schematic cross-sectional view of the swimming pool cover of

Figure 1, in use. Referring to Figures 1 and 2 of the drawings, a swimming pool cover 10 is formed as an inflatable structure comprising a main body 12 and a periphery 14, which are integrally formed. The main body 12 has a drop-stitch structure, whereas the periphery 14 has an air cell structure. The periphery 14, in this embodiment, extends all the way around the periphery of the main body 12, but that need not necessarily be the case in all embodiments.

The swimming pool cover 10 has a hollow interior volume 16, which can be inflated using, for example, an air compressor (not shown) and is formed by an upper skin 18 and a lower skin 20, which respectively form the upper and lower surfaces of the main body 12. The edges of the main body 12 are closed off by a web 22, which is adhered 24 to the upper 18 and lower 20 skins to form a generally D-shaped outer periphery, which is flexible.

The upper 18 and lower 20 skins are interconnected, at intervals by space yarns 26, which, when the hollow interior volume 16 is inflated, become taut, thereby maintaining the upper 18 and lower 20 surfaces of the main body in a desired relative configuration. Meanwhile, when the hollow interior volume 16 is inflated, the outer periphery 14 also inflates, but because it does not have any space yarns, is of a generally flexible, air cell structure.

Referring to Figure 3, a swimming pool 40 comprises a recess 42, which defines the swimming pool itself. The recess 42 has side walls 46 and a floor surface 48, which can be filled with water to form a swimming pool. The upper edges of the side walls 46 comprise a bullnose return/overhang lip 48, which slightly overhang the recess 42 and this type of return is typically found in most swimming pools.

To deploy the cover 10, the swimming pool cover 10 is first slightly inflated, so that it becomes buoyant, and it is then laid out on top of the surface of the swimming pool water and positioned as necessary. Further inflation of the swimming pool cover 10 causes the main body 12 and the peripheries 14 to inflate, and as it inflates, it will initially be flexible until such time the internal air pressure within the hollow interior volume 16 is sufficient to cause the space yarns 26 to become taut, at which point, the main body 12 will adopt a "rigid" configuration in which the upper 18 and lower 20 surfaces become hard and rigid.

Meanwhile, the periphery 14 will continue to inflate unrestrained (because it does not have space yarns within it) and will therefore expand to positively engage the side walls 46 of the swimming pool 40 as well as the underside of the returns 48, as can be seen in Figure 3 of the drawings.

Upon full inflation, the cover 10 will form a rigid structure in the form of the main body, which has become rigid and hard due to its drop-stitch construction; and fully-engaged with the swimming pool by virtue of the peripheries 14, which now positively engage and conform with the side walls 46 of the swimming pool 40 as well as the undersides 40 of the returns 48.

In Figure 4 of the drawings, which largely resembles the embodiment shown in Figure 3, the swimming pool cover 10 is fitted to an "infinity" pool, that is to say, a pool structure 40 having internal side walls 46, and at least one side wall 460 whose upper edge 462 is substantially level with the water level within the pool 40. This configuration creates a pleasing aesthetic arrangement in certain installations.

As the swimming pool cover 10 floats on the water within the pool 40, the drop-stich part

16/26 extends beyond the end wall 460 and comprises a return part 464 so that the air cell part 140 can face back towards the outer surface 466 of the end wall 460. Now, upon inflation of the swimming pool cover, the drop-stitch part 16/26 becomes rigid, the internal air cell parts 14 (sealingly) engage the inner side walls 46 of the pool 40, and the external air cell parts 140 (sealingly) engage the outer side walls 466 of the pool 40.

In Figure 4, one or more of the tiles 50 comprises a photovoltaic panel 51, which charges a battery 300 stored in a watertight enclosure 302, optionally located below the pool cover 10. The battery 300 is connected to a controller 304, which controls the operation of a pump/compressor 306. The pump/compressor 306 has an external air intake and an outlet connected to the interior of the pool cover 10. Also, the controller 304 is connected to an air pressure sensor 308 located within the pool cover 10. The controller is suitably configured to monitor the air pressure within the pool cover 10 using the air pressure sensor 308, and if it falls below a specified pressure, to turn on the pump/compressor 306 to re-inflate the pool cover 10. This configuration automatically controls the air pressure within the pool cover 10, keeping it safe. In the event of a system failure, the controller 304 can be configured to emit an audio/visual or remote alarm.

A further possibility is using the controller 304 to regulate the temperature of the water within the pool, for example, using a submerged heater 310 powered by the battery 300, as shown in Figure 4.

It will also be noted that the embodiment shown in Figure 4 has a modified tile 510, which engages 512 underneath the edge of an adjacent tile 50. The modified tile 510 has an upstand part 514, forming a wall structure to prevent or inhibit people or objects from falling off the end of the

"infinity" pool structure 40. Supplementary securing straps 516, which connect to eyelets 518 are also shown.

Another possibility is shown in Figure 5 of the drawings, which is largely the same as Figure 3 and identical reference signs have been used to identify identical features for the sake of clarity and brevity. Flowever, it will be noted that the air cell periphery 14 is slightly larger, and is thus able to conform to the shape of the bullnose overhang 48. Because the air cell periphery 14 conforms to the bullnose overhang 48, a seal is thus formed and the upper surface 18 of the drop-stitch main body 12 is now about flush with the walkway 52 surrounding the pool.

It will also be noted that the embodiment shown in Figure 5 of the drawings has a fastener arrangement, in this case, hook-and-loop fastener strips 504, disposed on the upper surface 18 of the pool cover 10, which connect to complementary fastener strips 504 or the undersides of the tiles 50. The tiles 50 are thus locked in-situ atop the pool cover 10, forming a stable structure. The outer tiles 500 have chamfered edges 502 to as to form a smoother transition between the walkway 52 surrounding the pool and the tiles 50, 500, thereby reducing potential trip hazards.

Thus, the swimming pool cover 10 effectively becomes "locked" into the swimming pool aperture - thereby providing a rigid cover for the pool. Because the swimming pool cover 10 is inflatable, it is fully supported across its entire width by the water underneath it, and because it is locked into position by the inflated peripheries 14, is laterally stabilised also.

As can be seen in Figure 3 of the drawings, a set of walkway tiles have been laid over (and optionally interlocked) the upper surface 18 of the main body 12 thereby providing a puncture-proof walking surface overlying the swimming pool cover 10. In certain embodiments, as can be seen in Figure 3, the thickness of the tiles 50 is substantially the same of the height of the returns 48 thereby providing a continuous, level walking surface between the pool deck area 52 surrounding the pool 42 and the walkway surface formed by the tiles 50.

The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. In particular, whilst the present invention has particular advantages for swimming pools on cruise ships, it can also be used in conjunction with almost any swimming pool arrangement/configuration.