Field of application of the invention

The present invention refers to the field of covering extensive surfaces via tarpaulins, for example covering the water surface of a swimming pool. More spe- cifically, the present invention refers to an inflatable cover tarpaulin that can be unrolled pneumatically.

Review of the prior art

Outdoor swimming pools, during periods of non-use, are covered with waterproof tarpaulins which allow reducing the costs of cleaning and maintenance by preventing leaves, insects and dirt from entering into the pool and contaminating the water contained therein (if, as usually occurs, the pool is not emptied). Swimming pool coverage also meets energy saving and safety needs. Tarpaulins indeed prevent the environmental dispersion of the steam that is liberated from the water in the pool, and in such a manner they reduce - especially dur- ing the summer - both water consumption and chemical additive costs, as well water heating costs before restoring swimming pool use. The latter result is even better in the case of thermally insulating covers. In addition, there are extremely resistant tarpaulins which, once suitably fixed to the ground (in the case of in-ground swimming pools) or to the walls of the pool (in the case of "above- ground" pools), are capable of supporting relatively high loads without being broken or excessively deformed, so as to prevent people (especially children) or pet animals from accidentally falling in the pool. The common cover tarpaulins for swimming pools are fixed by means of ropes or counterweights along the edges thereof. This ensures that, even if these covers are provided with good elasticity, the tarpaulins tend to be curved in the central zone, facilitating the accumulation of rainwater, snow or dirt. This fact constitutes a problem since at the time of reuse of the swimming pool, it is necessary to carefully remove said accumulations before removing the tarpaulin, otherwise the same would be poured in the pool, making the pool coverage effort futile. A similar operation leads to a considerable loss of time, especially in the case of very large pools.

In order to solve this problem, semi-rigid covers or covers constituted by tarpaulins supported by a reticular frame were ideated. However, these are not very practical and are extremely bulky. In order to prevent the accumulation of rainwater and snow, filtering covers have also been conceived constituted by a very dense mesh net. However, these are not capable of preventing the evaporation of the water or the entrance of dust into the pool.

One solution to the problem is given by the German utility model DE 20 2008 005 627 U1 which has as object a device for covering wide, flat surfaces, especially swimming pools, artificial lakes and transport means, comprising a tarpaulin that can be rolled on a winch and is composed of two waterproof sheets, thermally insulating and opaque to ultraviolet rays, superimposed and mutually glued along the edges to form a sealed chamber equipped with a valve for inserting or drawing air. With reference to swimming pools, the seal chamber, lacking air, is extended on the pool's water surface and subsequently inflated in a manner such that the outwardly turned sheet is convex. In such a manner, dirt, water and snow are not deposited on the tarpaulin, as they slide away.

The cover that is the object of the above utility model, like the other swimming pool tarpaulin covers, are folded and/or wound on a winch when not in use, in a manner so as to minimize the size thereof. At the time of their reuse, they are manually unrolled and/or spread on the water surface of the pool. However, this operation requires relatively long times, and in the case of particularly large pools, must be carried out by at least two people.

Objects of the invention Therefore, the object of the present invention is to overcome the aforementioned drawbacks and to describe a cover tarpaulin that can be wound on the drum of a winch, from which the tarpaulin can be automatically unrolled.

Summary of the invention

In order to attain such objects, the present invention has as object a cover tarpaulin comprising:

- two waterproof sheets superimposed on each other and adherent along a perimeter band arranged for the application of tarpaulin fixing means;

- a first pneumatic valve applied to one of said sheets in order to allow the in- flow of compressed air into a first air chamber formed between the two sheets, which by being inflated assumes a convex profile adapted to prevent the deposit of dirt or undesired material;

wherein according to the invention the tarpaulin also includes:

- a first channel in one of said sheets, preferably in central position, closed at the two ends to form a second air chamber extended from a first edge of the tarpaulin to an opposite free edge, said first edge being connectable to the drum of a winch on which the deflated tarpaulin can be wound;

- a second pneumatic valve applied to the first channel in proximity to said free edge in order to allow the inflow of compressed air into the second air cham- ber, whose progressive inflation causes the unrolling of the tarpaulin, as described in claim Ϊ .

Further characteristics of the present invention deemed innovative are described in the dependent claims.

According to one aspect of the invention, said first channel is in the lower sheet. According to one aspect of the invention, the tarpaulin also includes second channels parallel to the first channel, with the same length and in the same sheet, having one end closed in proximity to said first edge and the other end continuing into a transverse section converging in an adjacent channel, comprising the first.

According to one aspect of the invention, the tarpaulin also includes:

- two third channels parallel to the second channels on opposite sides with respect thereto, with the same length and in the same sheet, each communi- eating with the second channel adjacent thereto in proximity to said first edge;

- two pluralities of fourth channels which are externally and transversely diverged from respective third channels, from one end to the other of such third channels;

- two fold lines of the tarpaulin longitudinally extended between the two said edges and crossing the two pluralities of fourth channels, whose progressive inflation causes the spreading of the tarpaulin starting from a configuration in which two parallel edges are folded on themselves.

According to one aspect of the invention, the tarpaulin also includes two third pneumatic valves respectively applied to the two fourth channels adjacent to said free edge, in order to allow the complete deflation of the portions of the second air chamber at the third and fourth channels during the winding on the winch drum of the tarpaulin folded along said fold lines.

According to one aspect of the invention, the channels are obtained by gluing, to the sheet, the strip edges of the same flexible material.

According to one aspect of the invention, the channels are obtained in the same manufacturing process as the sheet.

According to one aspect of the invention, said tarpaulin fixing means are consti- tuted by a perimeter channeling between the two sheets equipped with a valve for the inflow and outflow of water.

Advantages of the invention

The tarpaulin that is the object of the invention allows automatically covering relatively extensive outdoor surfaces, such as: swimming pools, tennis courts, soccer fields and bocci courts. It can also be used for covering the trailers of trucks, often remaining outside, and thus subject to the accumulation of rainwater and dirt on their normal covers. The unrolling operation is relatively simple, only requiring the insufflation of air by means of a pneumatic valve.

Brief description of the figures

Further objects and advantages of the present invention will be clearer from the following detailed description of an embodiment of the same and from the enclosed drawings given as merely exemplifying and non-limiting, in which: - Figure 1 is a cross section view of an above-ground swimming pool covered by an inflatable tarpaulin that can be unrolled according to the present invention;

- Figure 2 is a plan view of the tarpaulin of figure 1 ;

- Figure 3 is a side view of the tarpaulin of figure 1 , deflated and nearly completely wound on a winch placed in proximity to one edge of the pool;

- Figure 4 is a partial top view of the tarpaulin, of the winch and of the pool of figure 3;

- Figures 5, 6 and 7 are lateral views of the tarpaulin, of the winch and of the pool of figure 3 which show the tarpaulin unrolling and inflation sequence;

- Figure 8 is a plan view of a variant of the inflatable tarpaulin of figure 2 which allows the automatic spreading thereof starting from a configuration in which two parallel edges are folded on themselves;

- Figures 9a and 9b are respectively top and bottom views of the tarpaulin of figure 8 folded as said;

- Figure 10 is a partial top view of the tarpaulin of figures 9a and 9b, nearly completely wound on a shorter winch than the preceding one;

- Figures 11 , 12 and 13 are top views of the tarpaulin and of the pool of figure 10 which show the tarpaulin unrolling and spreading sequence.

Detailed description of several preferred embodiments of the invention

In the following description, equivalent elements which appear in different figures may be indicated with the same symbols. In the illustration of one figure, it is possible to make reference to elements not expressly illustrated in that figure but in preceding figures. The scale and proportions of the various depicted ele- ments do not necessarily correspond to the actual scale and proportions.

Figure 1 shows an above-ground swimming pool 1 nearly completely filled with water 2 and covered by a tarpaulin 3 comprising two superimposed sheets 10 and 1 1 adherent along the entire perimeter, of which the edges 7 and 8 are visible in the figure; such edges are glued together for a section 14 in a manner so as to form a chamber 13 inflated with compressed air for the floating of the tarpaulin 3. The latter is fixed to the walls of the pool 1 at said glued section 14 by means of a rope 9 (as will be illustrated in figure 7). The sheets 10 and 1 1 are made of waterproof plastic material that is thermally insulating and opaque to ultraviolet rays. The chamber 13 assumes a convex profile at the upper sheet 10. The edges of the tarpaulin 3 are extended beyond the edges of the pool 1 , consequently the convex profile of the upper sheet 10 is extended for the entire length of the pool, including the thickness of the walls 5 and 6 of the pool visible in the figure. This ensures that the rainwater, snow and dirt, when deposited on the tarpaulin 3, slide on the sheet 10 beyond the edge of the swimming pool 1 , and thus fall to the ground. Three longitudinal strips 15', 16' and 17' of equal width, and of the same material as the sheets 10 and 11 , have their edges glued to the external face of the lower sheet 11 , in a respectively central position and in proximity to the longitudinal edges 7 and 8 of the tarpaulin 3. The strips 15', 16' and 17', as visible in figure 2, form, with the lower sheet 11 , a multichannel air chamber 18 inflated with compressed air.

With reference to figure 2, it is possible to observe that the tarpaulin 3 is rec- tangular and that the section 14 - where the sheets 10 and 11 are adherent - forms a frame 14c that encloses the air chamber 13. The frame 14c is crossed over its entire perimeter, in proximity to the external edge, by equidistant holes 20 reinforced by metal rings 21. At the strips 15', 16' and 17' of figure 1 , the air chamber 18 comprises three channels 15, 16 and 17 which are extended over nearly the entire length of the air chamber 13, parallel to the longer sides 7 and 8 of the tarpaulin 3, from a shorter side 24 to the opposite side 33. The lateral channels 16 and 17 continue in a transverse section, respectively 22 and 23, which are orthogonally joined to the central channel 15 close to the short side 24. The air chamber 18 therefore assumes a comb-like multichannel structure. A releasable pneumatic check valve 25 is applied to the upper sheet 10 in proximity to the short side 24, in order to allow the inflow or the outflow of compressed air from the air chamber 13. A releasable pneumatic check valve 26 is applied to the strip 15' at the end of the channel 15 in proximity to the short side 24, in order to allow the inflow or the outflow of compressed air from the air chamber 18.

Figure 3 shows a winch 30 lying on the ground close to the swimming pool 1 with rectangular base, with the drum 31 arranged parallel to a shorter wall 32 of the pool 1 , at a greater height than the upper edge 32a of the wall 32. The tarpaulin 3 is deflated and nearly completely wound on the drum 31 , starting from its shorter side 33. The drum 31 is rotated by a crank 34. The winch 30 also comprises a pair of opposite rollers 36 and 37, of same length as the drum 31 , arranged parallel thereto. The lower roller 37 is nearly at the same height as the edge 32a of the wall 32 of the pool 1 , projecting towards the latter with respect to the drum 31. In proximity to its short side 24, the tarpaulin 3 is inserted between the rollers 36 and 37 with the valves 25 and 26 projecting on the edge 32a of the pool 1. A row of hooks 35 for fixing the tarpaulin 3 is longitudinally connected to the drum 31 , in a manner such that the mutual distance between the hooks 35 is the same as that existing between the holes 20 of the tarpaulin 3. The latter is connected to the drum 31 along its short side 33 by means of a rope 38 fixed to the drum 31 at both ends; starting from one end of the drum 31 , such rope 38 is alternately inserted in a hole 20 of the frame 14c and made to pass around a hook 35 of the drum 31. Other hooks 40 are fixed to the walls of the pool 1 , at the same height and at the same mutual distance of the holes 20 of the tarpaulin 3. The longitudinal sections 14a and 14b of the frame 14c hang from the longer walls 5 and 6 of the pool 1 , with the holes 20 at a greater height than the hooks 40.

With reference to figure 4, it is possible to observe that the length of the drum 31 is about equal to the width of the tarpaulin 3, greater than the width of the pool 1.

Figure 5 shows the tarpaulin 3 unrolled on the pool 1 for about a third of its length, with the delivery tube 45 of a compressor (not shown in the figures) connected to the valve 26. The air chamber 18 is inflated in the unrolled section of the tarpaulin 3. The air in the chamber 18 ensures that the unrolled tarpaulin section 3 floats on the water 2 of the pool 1. The air insufflated by the compressor in the air chamber 18 initially travels through the transverse sections 22 and 23 and then the longitudinal channels 15, 16 and 17, proceeding towards the short side 33 of the tarpaulin 3 connected to the drum 31 of the winch 30. In such path, the air is blocked by the rollers 36 and 37 and the pressure that is generated against the latter is translated into traction forces that cause the pro- gressive unrolling of the tarpaulin 3. The presence of the channels 15, 16 and 17 and their orthogonality to the rollers 36 and 37 ensure that during the unrolling, the free edge 24 of the tarpaulin 3 advances such that it is always parallel to itself (and to the drum 31), without requiring sliding guides. In order to obtain the pneumatic unrolling of the tarpaulin 3, the traction forces must overcome the moment of inertia of the still-wound tarpaulin portion, of the drum 31 and of the rollers 36 and 37, and the viscous friction of the tarpaulin portion 3 already unrolled which is made to slide on the water. The winch 30, in the lower part, is equipped with a tank 46 that can be filled with water for the purpose of confer- ring greater stability thereto during the unrolling (and winding) of the tarpaulin 3. The rollers 36 and 37 optimize the unrolling maneuver without being essential for such purpose.

Figure 6 shows the tarpaulin 3 completely unrolled and the air chamber 18 completely inflated.

Figure 7, whose central cross section corresponds to figure 1 , shows the tarpaulin 3 of figure 6 after having been detached from the drum 31 by removing the rope 38; the air chamber 13 is illustrated completely inflated following the inflow of air by means of the compressor, after the delivery tube 45 has been disconnected from the valve 26 and connected to the valve 25. The transverse sections 14d and 14e of the frame 14c hang from the transverse walls of the pool 1 , with the holes 20 at a higher level than the hooks 40. The valve 26, being applied to the lower sheet 11 , is immersed in water and is thus hard to access due to the expansion of the air chamber 13. In the figure, the delivery tube 45 of the compressor has already been disconnected from the valve 25. The tarpaulin 3 is connected to the walls of the pool 1 along the entire frame 14c by means of a rope 47 fixed to the walls of the pool at both ends; such rope 47 is alternately inserted in a hole 20 of the frame 14c and made to pass around a hook 40 of the pool 1. As an alternative to the use of a rope, the fixing of the tarpaulin 3 to the pool 1 can occur by gluing together the sheets 10 and 11 , not over the entire surface of the frame 14c but only along its internal and external edge. In such a manner, without holes 20, a channel is created that surrounds the air chamber 13. By filling said channel with water via a suitable hydraulic valve, the frame 14c becomes a counterweight that fixes the tarpaulin 3 to the pool 1. In such case, it is however necessary to conceive a frame strip at the short side 33 of the tarpaulin 3 in which holes are to be made for the fixing of the tarpaulin 3 to the drum 31.

In order to remove the tarpaulin 3 from the pool 1 , it is necessary to:

a) open the valve 25 and wait a few moments for the air chamber 13 to be partially deflated;

b) remove the rope 47;

c) slightly lift the frame 14c of the tarpaulin 3 in order to access the valve 26 and open it;

d) make the short side 33 of the tarpaulin 3 pass through the rollers 36 and 37 and connect it to the drum 31 by means of the rope 38;

e) re-wind the tarpaulin 3 by actuating the winch 30 with the crank 34 until the valves 25 and 26 arrive in proximity to the rollers 36 and 37. The rolling of the tarpaulin between the rollers 36 and 37 compresses the air chambers 13 and 18, causing the progressive outflow of the air from the valves 25 and 26 during the winding.

Figure 8 is a plan view of a rectangular tarpaulin 50 that is different from the tarpaulin 3 due to a different structure of the air chamber 18. Three longitudinal channels 51 , 52 and 53 are obtained as previously stated by gluing the strip edges to the lower sheet of the tarpaulin 50, outside the air chamber 13. The channel 51 is in central position while the channels 52 and 53 are on opposite sides with respect thereto, closer together than the similar channels 15, 16 and 17 present in the tarpaulin 3. The rectangular tarpaulin 50 has two long sides 72 and 73 and two short sides 54 and 74, of which the side 74 is that which will be fixed to the drum of the winch while the side 54 is free. The central channel 51 is closed at the end adjacent to the short side 74. At one end adjacent to the same short side 54, the lateral channels 52 and 53 continue into a short transverse section, respectively 55 and 56, which are orthogonally joined to the cen- tral channel 51. At the other end, the channels 52 and 53 continue into a short transverse section, respectively 57 and 58, externally directed, which is orthogonally joined to two respective longitudinal channels 59 and 60 of the same length as the other channels. The channels 51 , 52, 53, 59 and 60 are equidistant. From each more external longitudinal channel 59 and 60, short, equidistant transverse channels diverge orthogonally and externally, from one end to the other, to form two respective pluralities 61 and 62 extended in proximity to the glued edge of the air chamber 13. A releasable pneumatic check valve 63 is applied to the upper sheet of the tarpaulin 50 in proximity to the short side 54 of the tarpaulin 50, in order to allow the inflow or outflow of air from the main air chamber formed between the upper sheet and the lower sheet. A releasable pneumatic check valve 64 is applied to the central channel 51 at the end adja- cent to the short side 54, in order to allow the inflow or outflow of compressed air from the air chamber formed by the longitudinal and transverse channels 51 , 52, 53, 55, 56, 57, 58, 59, 60, 61 and 62. Two releasable pneumatic check valves 65 and 66 are respectively applied to the two transverse channels 67 and 68 closest to the short side 54 of the tarpaulin 50, at the end furthest from the longitudinal channels 59 and 60, in order to allow the outflow of compressed air from the air chamber portion formed by the more external longitudinal channels 59 and 60 and by the transverse channels 61 and 62. Two fold lines 70 and 71 are longitudinally extended for the entire length of the tarpaulin 50, crossing the two respective pluralities of transverse channels 61 and 62. The fold lines 70 and 71 are symmetrical with respect to the longitudinal axis of the tarpaulin 50 and are at a mutual distance equal to half the width of the tarpaulin 50.

Figures 9a and 9b show the tarpaulin 50 of figure 8, respectively top and bottom views, folded around the fold lines 70 and 71. The longitudinal edges 72 and 73 mate and the holes 84 in the folded frame sections 75 are aligned with the respective underlying holes.

Figure 10 shows a winch 80 lying on the ground in proximity to the pool 1 with the drum 81 arranged parallel to the transverse wall 32 of the same, at a greater height than the upper edge 32a of said wall 32. The winch 80 differs from the winch 30 due to the fact that the drum 81 and the rollers have about half the length of the drum 31 and rollers 36 and 37. The folded and deflated tarpaulin 50 is nearly completely wound on the drum 81 starting from the short side 74. The connection between the tarpaulin 50 and the drum 81 is obtained by means of a rope, in the same manner as that between the tarpaulin 3 and the drum 31. The tarpaulin 50 is unrolled as much as needed such that the valves 63, 64, 65 and 66 are beyond the pair of opposite rollers of the winch 80, lying on the edge 32a of the pool 1. Incidentally, the advantage of winding the tarpaulin on the winch after having folded it consists of the smaller longitudinal size attained. Figure 11 shows the tarpaulin 50 completely unrolled on the swimming pool 1. Analogous to that stated for the tarpaulin 3, the unrolling took place by connecting the delivery tube of the compressor to the valve 64. The frame of the tarpau- lin 50 at its folded short side 54 hangs from the wall of the pool 1 (not visible in the figure). The air insufflated from the compressor initially travels through the transverse sections 55 and 56 and then the longitudinal channels 51 , 52 and 53, causing the unrolling of the tarpaulin 50. Once the unrolling has terminated, as soon as the transverse sections 57 and 58 become accessible, the inflow of compressed air is suspended. The air expands, traveling through the transverse sections 57 and 58 and then the longitudinal channels 59 and 60. During this expansion, the air loses pressure (since the compressor has been stopped) - this prevents it from proceeding into the transverse channels 61 and 62 beyond the fold lines 70 and 71. The tarpaulin 50 is then separated from the drum 51. Figure 12 shows the tarpaulin 50 of figure 11 partially spread out, after the inflow of compressed air into the HI^H through the valve 64 has restarted. The air travels through the longitudinal channels 51 , 52 and 53, reaches the transverse sections 57 and 58, and travels through the channels 59 and 60, progressively flowing into the transverse channels 61 and 62. Traveling through said transverse channels, the air is obstructed by the folds 70 and 71 of the tarpaulin 50, but the pressure is sufficient to cause the progressive spreading out of the tarpaulin 50 from the transverse sections 57 and 58 towards the free edge 54 of the tarpaulin.

Figure 13 shows the tarpaulin 50 completely spread out on the swimming pool 1. Analogous to that stated for the tarpaulin 3, the delivery tube of the compressor is detached from the valve 64 and the tarpaulin 50 is connected to the walls of the pool 1 along the entire frame by means of a rope. The delivery tube of the compressor is then connected to the valve 63 and the compressed air is inserted in the main chamber formed by the upper sheet and the lower sheet. In order to remove the tarpaulin 50 from the pool 1 , it is necessary to:

a) open the valve 63 and wait a few moments for the air chamber formed be- tween the lower and upper sheets to be partially deflated;

b) remove the rope used for fixing the tarpaulin 50 to the pool;

c) slightly lift the frame of the tarpaulin 50 in order to access the valves 64, 65 and 66, and open them in order to allow the air to exit;

d) partially fold the deflated tarpaulin along the fold lines 70 and 71 ;

e) make the short side 74 of the tarpaulin 50 pass between the opposite rollers of the winch 80 and connect it to the drum 81 by means of a rope;

f) re-wind the tarpaulin 50 until the valves 63, 64, 65 and 66 arrive in proximity to the rollers of the winch. The rolling of the tarpaulin between the rollers compresses the two air chambers, causing the progressive outflow of the air from the valves 63, 64, 65 and 66 during the winding.

The presence of the valves 65 and 66 is necessary, otherwise - once the transverse sections 57 and 58 are compressed - the air would remain trapped in the longitudinal channels 59 and 60 and transverse channels 61 and 62.

On the basis of the description provided for a preferred embodiment, it is obvi- ous that some changes can be introduced by the man skilled in the art without departing from the scope of the invention as outlined in the following claims.