INFLATABLE SURFACE-COVERING DEVICE

Abstract

A device for covering a rectangular surface is provided that includes a cover (10) rotatably mounted on a drum (2), the device being capable of winding and unwinding the cover between an uncovered position and a covering position, rails (6) attached along the longitudinal sides of the surface, each of the rails includes an opening (6o) allowing the longitudinal edges (10L) of the cover to be locked in an air-tight manner, a blower system (51) suitable for blowing air (51a) into a volume under the cover and a flap (41) having an end (41s) which is sealed over a whole length of the second transverse side of the surface, a free end (41L) opposing the sealed end, such that the free end of the flap is in contact with the surface, the flap forming an air-tight seal between the cover and the surface along the second transverse side thereof.

Claims

1. A device (1) for covering a substantially rectangular surface (3) delimited by first and second longitudinal sides linked to one another by first and second transverse sides, the device comprising, a cover (10) which is substantially airtight and watertight and that allows the surface (3) to be covered, the cover being delimited by first and second longitudinal edges (10L) that are substantially parallel and linked to one another by a movable end (10m) and by a static end (10s) fixed to the first transverse side in a substantially airtight manner, a drum (2) that is rotatably mounted and capable of winding and unwinding the cover (10) over its first and second longitudinal edges (10L) by displacement of the movable end (10m) of the cover along the first and second longitudinal sides of the surface, between, an uncovered position, in which the movable end (10m) is adjacent to the first transverse side, the surface not being covered by the cover, and a covering position, in which the movable end (10m) is adjacent to the second transverse side, the surface being thus covered by the cover, first and second rails (6) fixed along the first and second longitudinal sides of the surface, each of the first and second rails comprising an opening (6o) allowing the first and second longitudinal edges (10L) of the cover to be locked in a substantially airtight manner over a length corresponding to the portion of cover covering the surface when the cover is unwound, wherein the static end (10s) of the cover is fixed to the surface (3) in an airtight manner along the first lateral edge and the movable end (10m) is fixed to an axle (2a) of the drum (2) which is mounted on a longitudinal translation mechanism, comprising a trolley (21) transversely overhanging the surface (3) to be covered and supporting the axle of the drum (2), said trolley (21) comprising, at each of its ends, at least two rollers (33) resting on the first and second rails (6) allowing the longitudinal translation of the trolley (21), characterized in that the device comprises a blower system (51) capable of blowing air (51a) between the surface and an internal surface (10i) of the cover facing the surface (3) when the movable end of the cover is in covering position, and a flap (41) having a sealed end (41s) extending substantially parallel to, and over an entire length of, the second transverse side of the surface and mounted so as to follow the displacements of the movable end (10m) of the cover along the first and second longitudinal sides (10L), and a free end (41L) opposite the sealed end (41s), such that when the movable end (10m) is in covering position, the free end (41L) of the flap is in contact with the surface, and in that, with its sealed end (41s) and its free end (41L) which is in contact with the surface (3), the flap (41) forms an airtight seal between the cover and the surface along its second transverse side, allowing a substantially airtight volume to be defined between the surface and the internal surface of the cover when the movable end is in covering position and to create an overpressure in this volume by the blowing of air by the blower system (51).

2. The device as claimed in claim 1, wherein the rails (6) comprise a substantially U-shaped profile or a G shaped profile comprising a fin partially closing one side of the opening (6o) of the profile, or a C-shaped profile comprising two fins partially closing each side of the opening (6o) of the rails.

3. The device as claimed in claim 1, wherein (a) the trolley (21) comprises, at each of its ends, a driving wheel (9) disposed at a non-zero distance from the corresponding rail (6), on the same plane as, and between, the at least two rollers (33) and whose axis of rotation is parallel to that of said drum (2), (b) a belt (31) which is flexible extends along each of the first and second rails (6), fixed only at each of its ends to first and second ends (35) of the corresponding rail, and inserted into the opening (6o) of the corresponding rail in two sections (31a) of the belt (31) lying between the first and second rollers (33) and the first and second ends (35) of the corresponding rail, and capping, without slip, the driving wheel (9) in the section (31b) of the belt (31) lying between the at least two rollers (33).

4. The device as claimed in claim 2, wherein each rail (6) is formed by a G-shaped or C shaped profile with the opening (6o) oriented away from the surface (3), and with a fin situated on the side of the rail (6) adjacent to the surface, continuous insertion means allow the longitudinal edges (10L) of the cover to be inserted into the opening (6o) of each of the rails (6) as the cover (10) is unwound from the drum (2), and to be removed from the opening of each of the rails (6) as the cover is wound onto the drum, each longitudinal edge (10L) of the cover is provided with a bead (16) which, by the combined action of the belt being incorporated into the rail (6) and of the fin of the G-shaped profile, reversibly locks a longitudinal edge (10L) of the cover in the corresponding rail as the cover is unwound from the drum.

5. The device as claimed in claim 1, wherein the flap (41) has a width between its free (41L) and sealed (41s) ends lying between 150 and 600 mm.

6. The device as claimed in claim 1, wherein the sealed end (41s) of the flap (41) is fixed to the internal surface (10i) of the cover (10) by bonding and/or welding.

7. The device as claimed in claim 1, wherein the sealed end (10s) of the flap is fixed to the axle (2a) of the drum.

8. The device as claimed in claim 1, comprising one or more tongues (42) which are flexible and which link a portion of the flap (41) to a portion of the internal surface (10i) of the cover (10), wherein the flap has a length equal to the length of the movable end (10m) of the cover and has a width measured normal to its length, and wherein the one or more tongues are distributed over the length of the flap, and have a length measured between the flap (41) and the internal surface (10i) of the cover which is shorter than the section of flap lying between its sealed end (41s) and the portion of the flap to which the tongue or tongues are fixed.

9. The device as claimed in claim 1, wherein the trolley (21) and the drum (2) are enclosed in a box (61) comprising only one opening defined by a perimeter and extending over an entire length of the drum and facing the surface (3), wherein the sealed end (41s) of the flap (41) is fixed at least to a downstream or upstream portion of the perimeter of the opening of the box, wherein “downstream” and “upstream” are defined in the direction of displacement of the movable end (10m) of the cover allowing the surface to be covered, and wherein the flap (41) has a width between its free (41L) and sealed (41s) ends.

10. The device as claimed in claim 1, wherein the blower system (51) comprises an air outlet allowing air (51a) to be injected into the volume that is installed in a water draining gutter of a swimming pool, in a cavity of an edge of a swimming pool, on the cover (10), in a box as claimed in claim 11, or on an axle (2a) of the drum of a device as claimed in claim 3.

11. The device as claimed in claim 9, wherein the drum (2) comprises a hollow axle (2a) provided with a cavity, and orifices (2o) are distributed along the axle, fluidically linking the cavity with an outside of the axle and contained between the sealed end (41s) of the flap and the movable end (10m) of the cover, and wherein the blower device (51) is linked by fluidic connection to the cavity of the axle.

12. The device as claimed in claim 1, comprising a motor (30) actuating the displacement of the movable end (10m) of the cover.

13. The device as claimed in claim 1, wherein the surface comprises a cavity including a swimming pool, a potable water tank, or a pond containing aquatic animals, a tennis court, a pétanque court, or a curling court.

14. The device as claimed claim 9, wherein the flap (41) has a width between its free (41L) and sealed (41s) ends lying between 20 and 120 mm.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0038] These aspects and other aspects of the invention will be clarified in the detailed description of particular embodiments of the invention, reference being made to the drawings of the figures, in which:

[0039] FIG. 1 represents three configurations (a)-(c) of cover devices that are taut, floating and inflated, and (d) and (e) represent two devices according to the present invention covering (d) a surface comprising a cavity and (e) a flat surface;

[0040] FIG. 2 represents a first preferred embodiment of the invention comprising a movable drum being displaced along the surface from (a) an uncovered position, passing through (b) a partially covered position, to (c) a covering position.

[0041] FIG. 3 represents a second embodiment not belonging to the invention comprising a fixed drum and the cover comprising a free and movable end that is displaced along the surface from (a) an uncovered position, passing through (b) a partially covered position to (c) a covering position.

[0042] FIG. 4 represents different variants of flaps according to the present invention.

[0043] FIG. 5 represents different variants of rails and of systems for locking the longitudinal edges of the cover in a device comprising (a)&(b) a movable drum according to the invention and (c)&(d) a fixed drum according to the prior art.

[0044] FIG. 6 represents different variants of flaps forming an airtight seal at the movable end of the cover.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0045] The device (1) of the present invention allows a substantially rectangular surface (3) delimited by first and second longitudinal sides linked to one another by first and second transverse sides to be covered and uncovered automatically or semi-automatically. The device comprises a cover (10) which is flexible and substantially airtight and watertight. It needs to have dimensions allowing the surface (3) to be covered. The cover is delimited by first and second longitudinal edges (10L) that are substantially parallel and linked to one another, on one side by a movable end (10m) and, on the other side, by a static end (10s) which is fixed to the first transverse side in a substantially airtight manner.

[0046] The device comprises a drum (2) that is rotatably mounted and capable of winding and unwinding the cover (10) along its first and second longitudinal edges (10L). The winding and unwinding of the cover is accompanied by a displacement of the movable end (10m) of the cover along the first and second longitudinal sides of the surface. The movable end can be displaced between two extreme positions: an uncovered position and a covering position. The uncovered position corresponds to a situation in which the cover is entirely wound onto the drum, with its movable end (10m) being adjacent to the first transverse side of the surface. As its name indicates, in this position of the movable end, the surface is not covered by the cover.

[0047] The covering position defines a configuration in which the surface is covered by the cover which is unwound from the drum. The movable end (10m) of the cover is adjacent to the second transverse side.

[0048] The device of the present invention comprises first and second rails (6) fixed along the first and second longitudinal sides of the surface. Each of the first and second rails comprises an opening (6o) allowing the first and second longitudinal edges (10L) of the cover to be locked in a substantially airtight manner over a length corresponding to the portion of cover covering the surface upon the unwinding of the cover.

[0049] Optimizing the blowing of air under the cover in order to form a dome when the movable end (10m) of the cover is in covering position and the surface (3) is covered by the cover requires a volume defined between the covered surface and an internal surface (10i) of the cover (=“volume under the cover”) to be substantially airtight from the atmosphere in contact with an outer surface of the cover. Thanks, on the one hand, to the static end (10s) of the cover, which is fixed to the first transverse side in a substantially airtight manner and, on the other hand, to the first and second longitudinal sides (10L) which are locked in a substantially airtight manner in the corresponding rails (6), the volume under the cover (10) is substantially airtight over three of the four sides of the surface. If a sufficient seal cannot be ensured on the second transverse side, the pressurization of the volume under the cover cannot be done satisfactorily, demanding too much power and enormous energy consumption. It is therefore essential to seal the fourth side (i.e. the second transverse side) of the surface. The sealing of the second transverse side, when the surface is covered by the cover (10), is ensured by a flap (41).

[0050] As illustrated in FIG. 4, the flap (41) comprises a sealed end (41s) extending substantially parallel to, and over an entire length of, the second transverse side of the surface. It is mounted so as to follow the displacements of the movable end (10m) of the cover along the first and second longitudinal sides (10L). The flap also comprises a free end (41L) opposite the sealed end (41s), such that, when the movable end (10m) is in covering position, the free end (41L) of the flap is in contact with the surface. Thus, with its sealed end (41s) and its free end (41L) which is in contact with the surface (3), the flap (41) forms an airtight seal between the cover and the surface along its second transverse side, making it possible to define the volume under the cover which is substantially airtight over all four sides of the cover when the movable end is in covering position.

[0051] With the device of the present invention allowing the volume defined under the cover to be rendered substantially airtight, the device can comprise a blower system (51) capable of blowing air (51a) into the volume under the cover contained between the surface (3) and the internal surface (10i) of the cover facing the surface (3) when the movable end of the cover is in covering position and thus create an overpressure in this volume causing the cover to dish and form a dome.

Movable Drum (2)

[0052] In a first preferred variant of the invention illustrated in FIGS. 1(d), 1(e), 2, 4(a) to 4(c), 5(a) and 5(b), and 6(c) to 6(f), the drum (2) is mounted on a longitudinal translation mechanism, comprising a trolley (21) transversely overhanging the surface (3) to be covered and supporting the drum (2). The static end (10s) of the cover is fixed to the surface (3) in an airtight manner along the first transverse edge. The movable end (10m) of the cover is fixed to an axle (2a) of the drum (2).

[0053] The trolley (21) comprises, at each of its ends, at least two rollers (33) resting on the first and second rails (6) allowing the longitudinal translation of the trolley (21) between the first and second transverse sides of the surface. The translation of the trolley can be activated by a cable or chain mounting, by a rack system as described in WO2010010152, or by other systems.

[0054] For example, in a preferred variant, described in detail in WO2010054960 and illustrated in FIGS. 1(d) and (e), the trolley (21) comprises, at each of its ends, a driving wheel (9) disposed at a non-zero distance from the corresponding rail (6), on the same plane as, and between, the at least two rollers (33) whose axis of rotation is parallel to that of said drum (2) and with which it forms a triangle. A belt (31) which is flexible extends along each of the first and second rails (6), fixed only at each of its ends to first and second ends (35) of the corresponding rail. Each belt is inserted into the opening (6o) of the corresponding rail in two sections (31a) of the belt (31) lying between the first and second rollers (33) and the first and second ends (35) of the corresponding rail, and capping, without slip, the driving wheel (9) in the section (31b) of the belt (31) lying between the at least two rollers (33). The rotation (by a motor or a crank) of the driving wheel (9) drives the translation of the trolley with respect to the belts which are fixed, and thus allows the trolley to be displaced longitudinally between the first and second transverse sides of the surface.

[0055] The displacement of the drum along the rails (6) is illustrated in FIG. 2, with top and profile cross-sectional views of the displacement of the drum and of the movable end (10m) of the cover from (a) the uncovered position, (b) between the uncovered and covering positions, and (c) to the covering position, in which the surface is covered by the cover. Air (51a) can then be blown under the cover to pressurize the volume under the cover and thus impart a dome form to the cover. With a movable drum, the cover is placed on the surface without friction. As the drum advances toward the second transverse side of the surface, the longitudinal edges (10L) are inserted and locked into the opening (6o) of the rails.

[0056] As illustrated in FIG. 5(b), each rail (6) is preferably formed by a G-shaped or C-shaped profile with the opening (6o) oriented away from the surface (3), and with the fin situated on the side of the rail (6) adjacent to the surface. Continuous insertion means allow the longitudinal edges (10L) of the cover to be inserted into the opening (6o) of each of the rails (6) as the cover (10) is unwound from the drum (2), and then to be removed from the opening of each of the rails (6) as the cover is wound onto the drum. Such means are described in detail for example in WO2017130053. As illustrated in FIG. 5(b), each longitudinal edge (10L) of the cover is provided with a bead (16) which, by the combined action of the belt (33) being incorporated into the rail (6) and of the fin of the G-shaped (or C-shaped) profile, reversibly locks a longitudinal edge (10L) of the cover in the corresponding rail as the cover is unwound from the drum.

Fixed Drum (2)

[0057] In another variant of the present invention illustrated in FIG. 3, the drum (2) is installed in a fixed manner, adjacent to the first transverse side of the surface (3). The static end (10s) of the cover (10) is fixed to an axle (2a) of the drum and the movable end (10m) of the cover is a free end. In a particularly esthetic variant, the drum can be installed in a chamber situated under the surface to be covered (if the latter is substantially horizontal), thus concealing the drum from view. The chamber can also be designed to be substantially airtight in order to render the volume under the cover airtight on the side of the first transverse side. Alternatively, as illustrated in FIG. 4(d), the drum (2) can be located above the surface to be covered (if the latter is horizontal) thus rendering it visible. Other measures are necessary to seal the volume under the cover (10) on the side of the first transverse side, which are discussed later.

[0058] The displacement of the movable end (10m) of the cover along the first and second longitudinal sides of the surface requires the use of a cable and pulley mounting to pull the movable end (10m) toward the second transverse edge of the surface and thus cover the surface. To uncover the surface, it is sufficient to rotate the drum on its longitudinal axis to return the movable end of the cover to the first transverse side of the surface.

[0059] The displacement of the movable end (10m) of the cover mounted on a fixed drum is not part of the present invention is illustrated in FIG. 3 for information, with top and profile cross-sectional views of the displacement of the movable end (10m) of the cover from (a) the uncovered position, (b) between the uncovered and covering positions, and (c) to the covering position, in which the surface is covered by the cover. Air (51a) can then be blown under the cover to pressurize the volume under the cover and thus impart a dome form to the cover.

[0060] As illustrated in FIGS. 5(d) and 5(e), the longitudinal edges (10L) can be provided with beads (16) inserted into rails (6) comprising a substantially C-shaped profile, that is to say one comprising two fins partially closing each side of the opening (6o) of the rails. As illustrated in FIGS. 5(d) and 5(e), the openings (6o) of the first and second rails (6) are preferably oriented opposite one another.

The Cover (10)

[0061] The cover (10) comprises first and second longitudinal edges (10L) that are parallel to one another and linked to one another by a movable end (10m) and by a static end (10s). The cover is preferably of substantially rectangular form, at least on three of its four sides, the static end (10s) or the movable end (10m) not necessarily being straight or normal to the longitudinal edges. Preferably, the cover is rectangular.

[0062] The cover must be flexible to allow it to be wound onto the drum and it must be made of a substantially airtight material. Preferably, the cover is made of polymer, for example a vinylic polymer, or is a fabric impregnated or covered with a layer of polymer.

[0063] The longitudinal edges (10L) of the cover (10) are preferably provided with a bead (16). Beads suitable for the device of the present invention are described for example in WO2014064138. The beads can be present over a longitudinal strip that is bonded, welded, and/or stitched to the cover, thus forming the longitudinal edges (10L) of the cover (see FIGS. 5(b), 5(d) and 5(e).

[0064] In the variant of a movable drum of FIGS. 1(d)&1(e) and 2 described above, the static end (10s) of the cover is fixed in a substantially airtight manner to the first transverse edge of the surface (3). In the case of a swimming pool, the static end can be fixed to the edge of the swimming pool. The movable end (10m) of the cover is fixed to an axle (2a) of the drum and is displaced in translation with the drum (2) mounted on the trolley (21).

[0065] In order to synchronize the speed of translation of the trolley with the speed of unwinding/winding of the cover from/onto the drum, the trolley (21) preferably comprises a translation axle inserted coaxially into the axle (2a) and linked to the latter by a spiral spring which is relaxed when the movable end (10m) is in uncovered position adjacent to the first transverse side of the surface and is taut when it is in covering position, adjacent to the second transverse side of the surface. The translation axle is linked to the driving wheel (9) and, for example, to a motor (30). The rotation of the translation axle allows the trolley to be displaced along the rails (6). Upon a displacement of the trolley to the second transverse edge of the surface, the tension applied to the cover by the distancing from the drum drives the rotation of the axle (2a) of the drum and the progressive tension of the spiral spring. At a constant translation speed of the trolley, the speed of rotation of the axle (2a) varies with the diameter of the drum and accelerates when the movable end (10m) approaches the second transverse side and the diameter of the drum decreases. In the reverse direction of uncovering of the surface, the taut spiral spring ensures the rotation of the axle (2a) during the translation of the trolley to the first transverse edge.

[0066] Other systems for synchronizing the speeds of rotation of the drum and of the motor are possible, for example by circumferential contact of two rotating rollers or by any other system known to the person skilled in the art as for example described in the documents FR 2893651, DE 2257231 or FR 2908402. It is also possible to use two motors, one revolving at constant speed and driving the longitudinal translation of the trolley and the second provided with a microprocessor controlling the speed of rotation of the drum according to its diameter.

The Rails (6)

[0067] The rails (6) are fixed along the first and second longitudinal sides of the surface and each comprise an opening (6o). The opening (6o) allows the corresponding longitudinal edge (10L) of the cover (10) to be locked. In the case of a movable drum, the rails also ensure the guiding of the displacement of the trolley (21) by interacting with the rollers (33).

[0068] The rails (6) preferably comprise a substantially U-shaped profile or a G-shaped profile, that is to say comprising a fin partially closing one side of the opening (6o) of the profile, or a C-shaped profile, that is to say comprising two fins partially closing each side of the opening (6o) of the rails.

[0069] The rails must not only lock the longitudinal edges of the cover as the cover covers the surface, but they must also ensure that this locking forms a substantially airtight contact between the longitudinal edges of the cover and the rails. For example, as illustrated in FIGS. 5(b), 5(d) and 5(e), the interaction of the bead (16) with the fins of the rail (6) and, in the case of FIG. 5(b), in collaboration with the belt (31) which is also housed in the opening of the rail in the portions (31a) of the longitudinal edges of the surface, ensures a substantially airtight contact.

[0070] The expression “substantially airtight” does not require a perfect seal. The production of a perfect seal would be illusory or very expensive to implement. The airtightness required in the present invention is such that the pressure losses in the volume under the cover make it possible, using a conventional blower device, to ensure an overpressure of at least 10 Pa, preferably at least 50 Pa, more preferably at least 70 Pa. The pressure must be sufficient to lift the weight of the cover (10). The person skilled in the art can determine the optimal trade-off between the cost to improve the sealing of the longitudinal edges in the rails and the energy consumption cost to maintain such a pressure under the cover. For example, with a pressure under the cover of 50 Pa, the air leaks are preferably less than 50 m.sup.3/h, preferably less than 30 m.sup.3/h and more preferably less than 20 m.sup.3/h. A blower system (51) with an air flow rate (51a) of 100 to 300 m.sup.3/h can be used, preferably between 150 and 250 m.sup.3/h.

Flap (41)

[0071] In order to ensure a sealing of the volume under the cover at the second transverse side of the surface, the device of the present invention comprises a flap (41). The flap comprises a sealed end (41s) extending substantially parallel to, and over an entire length of, the second transverse side of the surface, and is mounted so as to follow the displacements of the movable end (10m) of the cover along the first and second longitudinal sides (10L). It also comprises a free end (41L) opposite the sealed end (41s). When the movable end (10m) is in covering position, the free end (41L) of the flap is in contact with the surface.

[0072] In a preferred variant of the invention illustrated in FIGS. 4(a)&4(d), the sealed end (41s) of the flap (41) can be fixed to the internal surface (10i) of the cover (10) by bonding and/or welding. The sealed end (41s) of the flap (41) is preferably adjacent to the movable end (10m) of the cover or, in any case, is substantially closer to the movable end (10m) than the fixed end (10s).

[0073] Alternatively, as illustrated in FIG. 4(b), the sealed end (10s) of the flap can be fixed to the axle (2a) of the drum.

[0074] In the preceding two variants illustrated in FIGS. 4(a), 4(b)&4(d), the flap (41) can have a width between its free (41L) and sealed (41s) ends preferably lying between 150 and 600 mm, preferably between 200 and 500 mm, more preferably between 250 and 400 mm, dependent on the dimensions of the surface. The width of the flap must allow the flap to form an airtight seal between the cover and the surface along its second transverse side, between its sealed end (41s) and its free end (41L) which is in contact with the surface (3). Since the volume under the cover is thus substantially airtight along the four sides of the surface (3), the volume under the cover can then be pressurized by the blowing of air by the blower system (51).

[0075] In a third variant illustrated in FIG. 4(c), the trolley (21) and the drum (2) are enclosed in a box (61) comprising only one opening defined by a perimeter and extending over an entire length of the drum and facing the surface (3). The sealed end (41s) of the flap (41) is fixed at least to a downstream or upstream portion of the perimeter of the opening of the box. The terms “downstream” and “upstream” are defined in the direction of displacement of the movable end (10m) of the cover allowing the surface to be covered. The flap (41) can have a width between its free (41L) and sealed (41s) ends lying preferably between 20 and 120 mm, preferably between 30 and 100 mm, more preferably between 40 and 70 mm.

[0076] In a variant illustrated in FIGS. 6(c) to 6(f), the box can comprise means for varying the distance h separating the surface (3) from the perimeter of the opening of the box. Such an arrangement is described for example in WO2014068131. The distance can be varied using jacks (63), preferably electrical, or levers, or worm screws. The position of the box can thus be varied in a direction normal to the plane containing the perimeter of the surface (3) between a translation position, in which the perimeter of the opening of the box, including the flap, is not in contact with the surface, and a contact position, in which the perimeter of the opening of the box contacts the surface and forms therewith a substantially airtight contact. In this variant, it is preferable for the flap (41) to extend over the entire perimeter of the opening of the box (61). The flap must ensure an airtight seal of the volume contained in the box when the latter is in contact position.

[0077] In the case where the surface comprises a cavity such as a swimming pool for example, the covering position of the drum can be defined as illustrated in FIG. 6(d) such that the entire perimeter of the opening of the box is outside of the cavity, for example on the edge of a swimming pool. The volume under the cover can then be pressurized as far as the flap (41) situated on an upstream portion of the perimeter of the opening of the box. In this case, the volume under the cover is separated from the volume in the box and it is preferable to install the blower system outside of the box, for example on the cover or in a wall defining the cavity of the surface (3).

[0078] If, however, as illustrated in FIG. 6(f), in the covering position of the drum, the upstream portion of the box overhangs the cavity, the volume under the cover is fluidically connected with the volume in the box, and the blower system can be provided on or in the box (see FIGS. 4(b), 4(c), 6(e) and 6(f). The blower system can also preferably be mounted on the axle (2a) of the drum, the interior of which is hollow and whose walls are provided with openings (2o) distributed over the length of the axle.

[0079] In another variant, the box cannot vary its distance h from the surface. In this case, the flap must ensure the sealing of the box at least in the covering position of the drum. In addition to the downstream portion of the perimeter of the box provided with a flap, the longitudinal portions of the perimeter of the opening must also be sealed, for example with lateral flaps (41e) also extending along the longitudinal portions, and whose free ends contact the surface during the displacements of the trolley (21). As illustrated in FIG. 4(c), in order to reduce the wear of the flaps, the surface can be provided, on its second transverse side, with a counter-sealing system which, in collaboration with the flap (41) and with the lateral flaps (41e), makes it possible to form a seal when the drum is in covering position. Thus, the flaps (41, 41e) of the box must not touch the surface during the displacement of the trolley, thus notably reducing the wear of the flaps.

[0080] The upstream portion of the trolley can also be provided with a flap or a seal. If necessary, the internal volume of the box can be compartmentalized with a separating wall (62) which, in certain configurations, makes it possible to simplify the sealing of the box on the upstream part of the perimeter of the opening, where the cover meets the surface.

[0081] Above all, but not solely, in the case of a movable drum, it is important, during the rewinding of the cover onto the drum when uncovering the surface, for the flap not to fold uncontrollably, thus increasing the diameter of the drum in uncovered position and, above all, preventing, during a subsequent covering of the surface, the flap from being positioned correctly when the movable end (10m) of the cover is in covering position. If the flap is badly positioned and its free end does not correctly contact the surface, the seal that is sought may be lost. To avoid this problem and as illustrated in FIGS. 4(a), 4(b) and (4d), it is preferable for the device to comprise one or more tongues (42) distributed over the length of the flap, which are flexible and which link a portion of the flap (41), preferably adjacent to the free end (41L) of the flap, to a portion of the internal surface (10i) of the cover (10). The tongues have a length measured between the flap (41) and the internal surface (10i) of the cover which is shorter than the section of flap contained between its sealed end (41s) and the portion of the flap to which the tongue or tongues are fixed. Thus, the flap is always presented with a good orientation when the cover is rewound onto the drum, rendering the mechanism more reproducible.

[0082] If necessary, as illustrated in FIG. 4(d), a second flap can be sealed to the internal surface (10i) of the cover on the side of the static end (10s) of the cover. Such an “upstream” flap may be necessary if it is difficult to ensure the sealing of the volume under the cover on the first transverse side.

Blower System (51)

[0083] The blower system can comprise one or more blowers (51) installed such that an air outlet allows air (51a) to be injected into the volume under the cover which is substantially airtight over the entire perimeter of the surface (3). Blowers as available on the market can be used, the power of which depends on the capacity of the volume under the cover and on the quality of the seal over the four sides of the surface. In most cases, a flow rate of 70 to 400 m.sup.3/h, preferably between 100 and 300 m.sup.3/h, more preferably between 150 and 250 m.sup.3/h can be applied to form a dome.

[0084] The blower system can be located in a water draining gutter of a swimming pool, in a cavity of an edge of a swimming pool (see FIGS. 2&3), on the cover (10), in or on a box (61), or on an axle (2a) of the movable drum. In order to be able to install a device according to the present invention on existing surfaces of any size and any configuration, it is preferable to be able to install the blower system on the device itself. For example, on the box (61) of a movable drum (see FIGS. 4(c), 6(e) and 6(f)), in a hollow axle (2a) of a movable or fixed drum (see FIG. 4(b)) or on the cover. A blower system installed on the hollow axle (2a) defining a cavity is preferred. The axle comprises orifices (2o) distributed along the axle, fluidically linking the cavity with an outside of the axle and contained between the sealed end (41s) of the flap and the movable end (10m) of the cover.

Advantages of the Present Invention

[0085] A cover device according to the present invention can be used to cover different types of surfaces, such as tennis courts, curling courts, pétanque courts, a skating rink, etc. The surface to be covered can also comprise a cavity, preferably intended to be filled with water, including a swimming pool, a potable water tank, or a pond comprising aquatic animals, or a methanization ditch.

[0086] The fact that the volume under the cover can be pressurized by the blowing of air by a blower system (51) makes it possible to impart a dome form to the cover (10), separating the cover from the covered surface. The dome form prevents rainwater from accumulating on the outer surface of the cover (10) and from causing sagging at its center. A significant proportion of this accumulated water finally ending up entering into contact with the surface, either by flowing through discharge orifices applied to the cover to avoid the formation of a pocket of water, or by uncovering the surface by the winding of the cover onto the drum. With the dome form, the rainwater flows by runoff to the periphery of the surface by gravity.

[0087] In the case of a curling track or a skating rink, the dome form isolates the iced surface from the atmosphere which, if it is at a temperature higher than 0° C., would result in higher energy demands to maintain the temperature of the ice below 0° C.

[0088] In the case of swimming pools, the present invention is particularly advantageous, because it allows a dome to be formed with the cover, as illustrated in FIG. 1(c) by pressurizing the volume under the cover, but also allows a floating cover to be formed as illustrated in FIG. 1(b), depending on whether the wish is to thermally isolate the water of the swimming pool from the ambient atmosphere (e.g., if the ambient temperature is lower than the desired temperature of the water) or, on the contrary, if the wish is to form a thermal bridge between the water of the swimming pool and the surrounding atmosphere (e.g. if the sun illuminates the cover and there is a desire to raise the temperature of the water. The pressure under an inflated cover can be reduced rapidly by displacing the movable end (10m) of the cover so as to break the seal on the second transverse side. Alternatively, the device can comprise a depressurization valve which can be opened to reduce the pressure under the cover and allow it to rest on the surface of the water.

[0089] By pressurizing the volume under the cover only when the movable end (10m) is in covering position, it is possible to have the longitudinal edges (10L) slide into the rails (6) during the displacement of the movable end without the cover being taut as illustrated in FIG. 1(a). This makes it possible to extend the life of the beads (16) of the longitudinal edges of the cover (10).

[0090] Finally, when the cover forms a dome, the outer surface of the cover is perfectly smooth and gives a superior esthetic appearance.

TABLE-US-00001 # Feature  1 Cover device  2 Drum  2a Axle of the drum (3)  2o Air opening in the axle (2a)  3 Cover  6 Rail  6o Opening of the rail  9 Driving wheel 10 Cover 10i Internal surface of the cover 10L Longitudinal edge of the cover 10m Movable end of the cover 10s Static end of the cover 16 Bead 21 Trolley 30 Motor 31 Belt 31a Portion of belt (31) excluding the portion (31b) contained between the rollers (33) 31b Portion of belt (31) contained between the rollers (33) 33 First and second rollers 35 End of a belt 41 Flap 41e Lateral sealing of the box 41L Free end 41p Sealing station in covering position 41s Sealed end 42 Tongue 51 Blower device 61 Box 62 Internal sealing wall 63 Pistons for varying the height of the box