Technical Field

The proposed invention relates to the upper inflatable edge of canvas pools, particularly to an interchangeable inflatable tube for canvas pools, such as those which comprise an upper inflatable ring or tube that defines the upper edge.

State of the Art

A number of canvas pools are known in the art, the most popular ones being those comprising a canvas body held by a skeleton framing made of pipes embedded through corners, which define a pipe upper edge and a series of legs or headers and side supports.

An example of canvas pools that form part of the closest prior art are the canvas pools with an inflatable upper edge which, depending on the pool’s configuration (either rectangular or circular), may or may not have side support legs. These types of swimming pools meant an important step in the prior art by removing the perimeter tubular structure and replacing it with an inflatable perimeter tube or ring that defines the upper edge of those pools.

One of the inconveniences that appeared as a result of this configuration is that inflatable perimeter tube or ring was exposed to breakage or punctures, which caused the need to repair, patch or in worse cases, replace the pool. Thus, as the perimeter inflatable tube is also the upper structural frame of the pool, over all in a circular configuration, lacking external support such as supports and is only held up by water pressure exerted against the side walls of the pool that ends at the inflatable tube.

An attempt in this sense is the Utility Model of same Applicant AR081956B4 proposing a interchangeable inflatable tube through the precut sections in the external tube, notwithstanding, the users reports referring to the inflating process and introducing a new interchangeable tube through the precut sections in the original external tube were tiresome and complicated.

Other prior art documents are also known which describe various canvas pools with inflatable accessories.

Publication AR 082877A4 of the same Applicant describes an continuous inflatable tube for canvas pools comprising an inflatable perimeter ring or tube delimiting the upper border of the pool, wherein the tube is a continuous and complete strip, without stitching or joints, and comprising a lower longitudinal edge of about 3 or 4 cm which is used to weld said tube to the edge of the canvas pool. Said tube consists in a strip of flexible material, preferably PVC, forming a continuous cylindrical ring welded by radiofrequency to the upper edges of the side walls of the canvas pool, comprising at least a blowing up valve, by which the user blow up the tube to the desires volume. However, the ring or tube of the cited prior art document is welded to the side of the pool and therefore, the prior art document neither mentions nor suggests coupling the ring or tube by simple support on the side of the pool and free of welding to the sides of the pool and protected by an enveloping cover, that allows to easily replace the ring or tube if punctured.

Patent US 10,769,291 B1 discloses a raised pool comprising a flexible pool body. The flexible pool body comprises: polygonal bottom sheet comprising a plurality of edge portions and an plurality of side sheets, each side sheet comprising a part of the side wall of the pool and a part of the bottom of the pool, and each of the side parts of the pool and each of the bottom parts of the pool have an isosceles trapezoidal shape. Each of the side wall portions of the pool comprise a first portion of the upper base, a first portion of the lower base and a first medium portion defined between the first portion of the upper base and the first portion of the lower base, and each portion of the bottom of the pool comprises a second portion of the upper base, a second portion of the lower base and a second medium portion defined between the second portion of the upper base and the second portion of the lower base. The first part of the lower base and the second part of the lower base coincide to define joining of the part of the side wall of the pool and the bottom part of the pool. The first medium portions of the side sheets are successively connected to form a side wall of the pool on the ground and the second medium portions are successively connected to form an external ring of the bottom of the pool on the ground. The second portions of the upper base of the bottom portions of the pool are respectively connected to the portions of the edge of the bottom sheet. However, the prior art document cited neither mentions nor suggests coupling a ring or tube free from welding to the body of the pool by an enveloping cover and allowing to easily replacing the ring or tube if punctured.

Patent US 6,408,453 B1 discloses an inflatable swimming pool with a surrounding wall that limits a housing space and that ends in an upper surrounding edge portion to define an opening. A flexible cover has an upper main wall to rest on the upper surrounding edge portion to cover the opening, and a flap portion that can be pulled to position beyond and outward and downward from the upper surrounding edge portion when used stretches the flexible cover. A flexible sheet member has a peripheral edge portion that is in sealed connection to the upper main wall to confine an inflatable space there between to be inflated to stretch the flexible cover. An inflation valve is provided to inflate or deflate the inflatable space. However, the cited prior art document does not describe mounting a ring or tube free of welds to the body of the pool by means of an enveloping cover and that allows the ring or tube to be easily replaced if it is punctured.

Patent US 6, 571 , 405 B1 describes a great capacity reinforced pool for use in an environment on the ground including a flexible plastic covering to contain water. The covering includes a continuous side wall and a lower wall attached to the lateral wall with stitching. The continuous side wall is formed by partial external layer and a partial inner layer.

An upper inflatable ring is mounted in the upper part of the side wall to support the covering in a vertical position. A continuous reinforcement layer is attached to the continuous side wall with a first plurality of continuous reinforcement joints to reinforce the side wall. A second plurality of continuous reinforcement seals situated in an interface between the partial external layer and the partial inner layer of the side wall which function is to reinforce the side wall. Each of the first and second plurality of continuous reinforcement seals includes at least two seals. However, this prior art document neither describes nor suggests mounting a welded-free ring or tube to the body of the pool by an enveloping cover and that allows to easily replace the ring or tube if punctured.

Therefore, it is necessary to have an inflatable ring or tube system, complying with the condition of resistance and durability, allowing replacing the damaged inflatable tube and overall, facilitate assembly for the user when replacing the punctured tube by a new inflatable tube.

Brief Description of the Invention

In a preferred embodiment, the present invention consists in a canvas pool, comprising in the upper mouth an interchangeable inflatable ring or perimeter tube which provides rigidity and structural support thereof, wherein said inflatable ring or tube is covered by an enveloping upper sheath entirely manufactures as a single item.

Said inflatable ring or tube consists in a flexible material tube, preferably PVC, which conforms a continuous ring comprising a least a pumping valve, by which the user will inflate the ring or tube to the desired volume. Said inflatable ring or tube is arranged by simply being supported on the upper edge of the canvas pool, without being welded or attached thereof in any manner and is retained in position thereof by the elastic material cover which envelops it and a threading nerve which keeps it in place. The cover elastic material comprises a nylon material enveloped on only one side with polyurethane. The problem to be solved is to provide a canvas pool wherein the inflatable tube can be easily replaced if broken or punctured. The particular configuration of the present invention allows, as the interchangeable inflatable tube is only leaning on the upper mouth of the pool and not welded thereof, to easily remove the interchangeable tube if damaged or punctured by only lifting up the enveloping upper cover, placing a new inflatable tube appropriately covered with enveloping upper cover, and pumping thereof till the inner pressure of the air in the tube adheres to the inner face of the upper enveloping cover. The presence of the adjustment nerve will not interfere with removing the cover as, the tube being deflated; it can be removed upwards only unfolding the cover.

Brief Description of the Figures

Figure 1 , is a front upper perspective view of the preferred embodiment of the canvas pool with interchangeable inflatable tube and enveloping upper cover.

Figure 2 is a side view of the pool of Figure 1

Figure 3a, is a cross-section view in direction A-A’ of Figure 2.

Figure 3b, is an outline representing the direction of the air pressure exerted against the tube walls on the enveloping cover of the pool of the preferred embodiment.

Figure 3c shows the adjusting nerve location.

Figure 4a shows a typical side section of the pool, being trapezoidal.

Figures 4b and 4c illustrate a welding sequence of two side sections in corresponding front elevation views of the pool of Figure 1 .

Figures 5a - 5g show the construction sequence of the canvas pool of Figure 1 with the interchangeable inflatable tube and continuous enveloping upper cover, from welding of parts thereof.

Figure 6 is a perspective view with volume of the pool of Figure 1 , once pumped and filled with water by the user.

Figures 7 to 14 show the sequence of assembling and pumping of the canvas pool of Figure 1 , with interchangeable inflatable tube and enveloping upper cover formed by a one piece strip.

Figure 15, is a front upper perspective view of an alternative embodiment of the canvas pool with interchangeable inflatable tube and upper enveloping cover.

Figure 16 is a side view of the pool of Figure 15.

Figure 17a is a cross-section view in direction A-A’ of Figure 16.

Figure 17b, is an outline representing the direction of air pressure exerted against the tube walls on the pool enveloping cover. Figure 18 shows a front view of a first embodiment of the side section of the pool with enveloping upper cover of Figure 15.

Figure 19 shows a front view of an alternative embodiment of the side section of the pool of Figure 15, separated from the enveloping upper cover.

Figure 20 is an outline wherein the proportion of the edges and curves of the enveloping cover is shown relative to the base side section of the pool of Figure 15.

Figures 21 and 22 illustrate a welding sequence of two side sections with enveloping upper covers in corresponding front views of the pool of Figure 15.

Figure 23 is an outline of perspective transparent lines showing how the enveloping cover is formed, as the side sections of the pool of Figure 15 are welded.

Figure 24 is a side external perspective represents the outline of Figure 23, showing how the two welded sections remain forming the enveloping upper cover of the pool of Figure 15. Figure 25 shows the same attachment of the side sections as does Figure 24, but in front perspective.

Figure 26 illustrates a side perspective of a section of the pool of Figure 15 with the enveloping cover in position, and

Figure 27 to 34 show the sequence of assembling and inflating the canvas pool of Figure 15, with interchangeable inflatable tube and enveloping upper cover formed by welded sections.

DETAILED DESCRIPTION OF THE INVENTION

Next we will describe the preferred embodiment of the present application.

In Figures 1 and 2 there are corresponding perspective and front views of the canvas pool (1) in use position, showing the enveloping cover (2) that covers the inflatable ring or tube (4) completely pumped, which is in the inner part, and the lateral wall of the canvas pool, made up of a succession of side sections (3) welded by hot air, ultrasound or radiofrequency. In the cross-section view 3a can clearly be seen how the inflatable ring or tube (4) supporting the canvas pool (1) is completely covered by the enveloping upper cover (2) that protects from the external exposure. The end terminal (a) of the enveloping cover (2) is inserted in the folding area (DZ) which is formed between the inflatable ring or tube (4) and the vertical portion of the enveloping cover (2). Said end terminal (a) of the enveloping cover (2), has the folding formed when welding a portion of the cover on itself (DZ). The folding (DZ) avoids that the edge of the material to be exposed, which would allow it to break or fray, and in this embodiment the folding (DZ) can also be used to place a not stretchable inner nerve (13), avoiding the ring from being uncovered once pumped, i.e., maintaining the cover (2) in position even when the inflatable ring or tube (4) completely deflate. The nerve (13) can comprise a plastic rope, preferably polypropylene, nylon, polyethylene, polyester, with or without PVC covering, and preferably with a diameter in the range of 4 to 8 mm or a strip made with the same water-proof material canvas of the pool, of 15 mm to 30 mm width. Such as plotted in Fig. 3b, as the continuous tube conforming the inflatable ring or tube (4) is pumped, pressure P of the air uniformly forces on the surface on the external enveloping cover (2), causing closure on the inflatable ring or tube (9) and once pumped, not be possible to remove the enveloping upper cover (7), because of the continuous pressure all along the inflatable ring or tube (9).

Figure 4 shows the base side section (3) having a trapezoid form, with two side faces (e), a lower bigger base (BM) and a upper smaller base (bm). This base side section (3) behaves in the same manner as in standard inflatable pool, the bigger base (BM) is welded to the poll floor, while the smaller base (bm) is where the inflatable ring or tube (4) is placed. In this manner, the greater base (BM) generates a bigger diameter at floor height and the smaller base (bm) defines a smaller diameter at the inflatable tube (4) height; i.e. , the canvas pool (1) mouth.

Next, we shall explain in detail, the steps to follow in this embodiment of the invention, for manufacturing the pool such as shown in Fig. 5a-5h and carried out as follows:

(i) provide the canvas to form the floor and sides of the pool and provide the elastic material to form the enveloping upper cover (2);

(ii) cut the canvas to form the floor (10) of the pool (5a);

(iii) cut the canvas to form the trapezoidal sections (3) conforming the sides (Fig. 5b);

(iv) weld the side sections to each other to form a complete side (3) (Fig. 5c);

(v) weld the complete side with the floor (Fig. 5d) (the bigger semicircle is the one welded to the floor);

(vi) cut the elastic material to form the enveloping cover (2) of the ring (Fig. 5e) having two edges and two ends;

(vii) welding a first edge of the cover (2) to the upper perimeter (bm) of the side (3) (Fig. 5f):

(viii) join the two ends of the cover (2) by welding (Fig. 5g);

(ix) forming a fold (DZ) along all the second fold of the cover (2);

(x) welding the free edge (a) of the fold (DZ) to form a housing of the nerve (13);

(xi) thread the nerve (13) into the fold (DZ); and (xii) welding the ends of the nerve (13) to form a closed loop.

The welding of the section with each other, as well as the welding of the complete side with the floor, welding of the side with the cover, the ends of the cover with each other and welding of the edge of the fold are performed with radiofrequency, hot air or ultrasound and also the ends of the adjustment nerve with each other are welded by radiofrequency, hot air or ultrasound or knotted if formed by a rope. However, if the verve is a canvas strip, the ends can be sewn, bonded with an adequate adhesive or welded by heat or ultrasound or radiofrequency.

Figures 4b and 4c schematically show the side welding process of each base side section

(3). Two trapezoidal pieces are overlapped one on the other, along their edges (e) maintaining both greater base (BM) at the same end and the sides of each piece are welded by hot air, ultrasound or radiofrequency.

The enveloping upper cover (2) of this preferred embodiment aims to conform a protecting envelop for the inflatable ring or tube (4), that is not adhered to the pool, but only leans or mounted on the upper smaller base (bm) of the base side section (3).

The enveloping upper cover of this embodiment (2) comprises a single, continuous, rectangular, piece of extensible material and which length is the same as that of the inflatable ring or tube (4) and which height is the sum of the circumference of the inflatable ring or tube

(4) plus a section which will serve to generate a terminal edge (a), which is folded on itself and welded (DZ), to house the rope or adjustment strip (8)

The fold at the edge (a) of the enveloping cover (2) is performed to generate a housing for the adjustment nerve (13), which assures the cover cannot be removed while the inflatable ring or tube (4) are completely pumped, the inner air uniformly exerting sufficient pressure on all the surface of the external enveloping cover (2).

Figures 1 and 2 show the finished pool wherein the inflatable ring is contained inside the cover (2).

Once the canvas pool has been manufactured and in the user’s hands, it is worth highlighting the steps necessary to assemble it, which are detailed in the sequence of Figures 7 - 14. The user separately receives the folded canvas pool (1) and the deflated inflatable ring or tube (4). Figure 7 shows how the user positions the pool (1) where it is to be used and will unfurl the side walls of the pool (1) comprised of the succession of welded side sections (3) and the corresponding enveloping cover section (2) in the upper end. Next, must unfold the inflatable ring or tube (4) and proceed to pump it using the pump, such as show in Figure 9. Once the inflatable ring or tube (4) is moderately pumped, the user will place it on the attachment region of the side sections (3) and the upper enveloping cover (2) as shown in Figure 11. This process can be carried out both with the pool empty as well as full. Figure 11 has been sketched as a half-full pool, with a volume of water sufficient to shape the canvas pool (1).

Once the inflatable ring or tube (4) has been placed, the user must completely cover it with the enveloping upper cover (2). For this, must insert the pumping valve (VA) provided on the inflatable ring or tube (4) through the hole (OR) of the enveloping upper cover (2) as illustrated in Figures 12 and 13, then continue covering the inflatable ring or tube (4) with the enveloping upper cover (2) according to the sequence shown in Figures 14 and 15. In the latter, covering with the enveloping cover has been completely performed, while the pool continues to be filled and finish pumping the inflatable ring or tube (4) through the pump, causing the air pressure to uniformly force on all the external enveloping cover surface (2), generating it to close around the inflatable ring or tube (4) without it being possible to be removed, due to the continuous pressure in all the extension of the inflatable ring or tube (4).

Final Figure 14 illustrates the canvas pool (1) in a position to be used, full of water and with the inflatable ring or tube (4) completely pumped.

If punctured and having to change it by a new one, the user will only need to remove the punctured tube and install a new one already pumped, following the steps described in the sequence of Figures 7 - 14.

Removal of the damaged inflatable tube can be easily performed, as what keeps it in position is the pressure exerted by the air inside. Upon said tube (4) being punctured and losing the inner air, will no longer exert pressure P against the walls of the enveloping upper cover (2) and hence, removal of the punctured tube can be easily executed lifting the enveloping upper cover (2) and removing the punctured tube (4), already without air inside. With the deflated tube, the nerve (13) will cause no impediment to easily remove the protecting cover. The canvas is manufactured by the inventor in rolls which can be up to around 2000 m in length and with a width depending on how it is cut between 1 ,68 m and 2,05 m.

The elastic cover is provided by third parties and is received in rolls of up to 50 m in length and a width of 1 ,47 m with a real working width of around 1 ,25 m.

The cutting of the sections, the floor and the cover are performed in two ways: (i) manually with an electric tool similar to a carpet knife but with a blade with no teeth at low production times or (ii) with an automatic type CNC cutting machine when production is high. The welding of all the joints is performed by a welding machine by hot air or a welding machine by radiofrequency, accordingly. In the case of welding with hot air, to join the canvas sections to each other, the side of the complete canvas with the floor or the ends of the nerve to each other, the temperature can vary between 350 °C and 600 °C, depending on the welding speed of 2 m/min to 7 m/min.

For welding the elastic cover with the full side, to form the fold of the cover, or to join the ends of the cover to each other, the temperature of the hot air welding is 500 ° C to 700 ° C, depending welding speed from 2 m I min to 7 m / min.

Table 1 shows the data of the assays to determine the minimum parameters of satisfactory welding.

The maximum values of welding speed depend on the operator and of each machine capacity. The machine most usually used allows a Vmax 15 m/min, at 750°C and 1 Mpa of maximum pressure, as long as the air system can provide it. The minimum speed is considered to be 2 m/min, but can be welded as from 0,01 m/min, a normal speed for an experienced operator being between 5 and 7 m/min

In all the cases the constants are: tightening rollers of knurled stainless steel with a thickness of 30 mm and a 30 mm nozzle.

Table 1

The welding is considered satisfactory if after welding at least 500 mm in length and trying to unstick thereof, the thread PVC or polyurethane (PU) of the anchoring material is unstuck and at no point the PVC of PU becomes unstuck.

In the case of radiofrequency welding, is performed at around 27 Mhz, both for welding of canvas section edges to each other, welding of the complete side with the floor, the complete canvas side edge with the edge of the cover or for the edges of the cover to each other, varying the wave amplitude and welding time.

The pool shown in the figures is representative of a series of different similar models of different sizes and capacity. In a preferred example, the size shown is of 4 m in diameter and 1 m in height to retain 1000 liters of water.

In an alternative embodiment, the object of the invention also consists in a canvas pool comprising an exchangeable inflatable tube defining the perimeter upper edge of said pool, wherein said interchangeable inflatable tube is covered by an enveloping upper cover, but in this alternative embodiment the upper cover is not formed by a single piece, but is an extension of the canvas side sections that make up the side walls of the pool.

The alternative embodiment of the proposed invention is a canvas pool (6), of the type comprising in its upper mouth a perimeter interchangeable inflatable ring or tube (9) providing rigidity and structural support thereof, wherein said inflatable ring or tube (9) is covered by an enveloping upper cover (7).

Said inflatable ring or tube (9) consists of a flexible material tube preferably PVC, conforming a continuous ring comprising at least a pumping valve, by which the user will pump the ring or tube to provide the desired volume. Said inflatable ring or tube (9) is arranged by simply leaning it on the upper edge of the canvas pool (6), without being welded nor attached in any manner thereto.

In this alternative embodiment of the invention, the enveloping upper cover (7) is welded to the upper edge of the side section (8) of the canvas pool, conforming a continuous side wall, which at the same time, is welded in the lower edge to the floor (12) of the pool.

Figures 15 and 16 show corresponding perspective and front views of the canvas pool (6) when in use, showing the enveloping cover (7) covering the inflatable ring or tube (9) completely pumped, which is inside thereof, and the side wall of the canvas pool, formed by a succession of side sections (8) welded by hot air, ultrasound or radiofrequency.

In the cross-section view 17a can be clearly seen how the inflatable ring or tube (9) supporting the canvas pool (6) is completely covered by the upper enveloping cover (7), which protects from external exposure. The terminal end (a) of the enveloping cover (7) is simply placed inside the fording region (DZ1) formed between the inflatable ring or tube (9) and the vertical portion of the enveloping cover (7), the same as that of the preferred embodiment. Said terminal end (a) of the enveloping cover (7) having a fold to generate an adjustment nerve, is simply manually placed between two surfaces mentioned before and as plotted in outline 17b, as the continuous tube making up the inflatable ring or tube (9) is pumped, pressure P of the air uniformly forces on all the surface of the enveloping external cover (7), causing it to closed around the inflatable ring or tube (9) and causing once pumped, making it impossible to remove the enveloping upper cover (7) due to the continuous pressure all along the inflatable ring or tube (9).

Manufacturing the side wall of the canvas pool (6) can be performed in two ways: as shown in Figure 18, with a single element (11) having the upper enveloping cover (7) and the side base section (8); or by means of two separate elements as illustrated in Figure 19, first producing the side base section (8) cut, then adding the enveloping upper cover (7) by welding by radiofrequency, hot air or ultrasound. In both cases, the enveloping upper cover (7) constitutes an extension of the side base section (8).

Figure 20 details the characteristics of the base side section (8), basically having a trapezoidal shape, with two lateral sides (e), a lower greater base (BM) and upper smaller base (bm). This base side section (8) behaves in the same manner as that of standard inflatable pools, the greater base (BM) is welded to the floor of the pool; while the smaller base (bm) is where the inflatable ring or tube (9) is placed. In this way, the greater base (BM) generates a bigger diameter at floor height and the smaller base (bm) defines a smaller diameter at the height of the inflatable tube (9), i.e., at the mouth of the canvas pool (6).

The enveloping upper cover of the alternative embodiment (7) which aim is to be a covering for the inflatable ring or tube (9), that is not adhered in any way to the pool, but simply leans or is mounted on the smaller upper base (bm) of the base side section (8).

The same Figure 20 shows the particular configuration of the enveloping upper cover of the alternative embodiment (7), which comprises a lower edge (d) exactly having the same length as the section (8) lower edge (bm), as both can be welded as mentioned before, if the manufacturing is performed in two elements.

The enveloping upper cover of the alternative embodiment (7) comprises sinusoidal side edges, with a concave portion (cv) defining a minimum inner distance (c), which function is to diminish the diameter of the pool to accompany the inner diameter of the inflatable ring or tube (9). Next, the section of the enveloping cover (7) is broadened till is defines a convex portion with a maximum inner distance (b). Between the minimum distance (c) and the maximum distance (b), what is ought is to progressively increase the diameter, wherein the intermediate part between the distances (c) and (b) correspond to the upper part of the inflatable ring or tube (9) and the maximum distance (b) corresponds to the external diameter of the inflatable ring or tube (9), which constitutes the greatest diameter of the pool.

After the section of maximum inner distance (b), the section of side section (8) begins to diminish again until it reaches the edge (a), terminal portion with which external lower portion the inflatable ring or tube (9) is finally enveloped. This terminal edge (a) is folded on itself and welded, to produce an adjustment nerve. The length of the edge (a) is exactly the same as lower edge (d), which causes that on folding is at the same height thereof.

Figures 21 and 22 schematically show the side welding process of each element (11) of the alternative embodiment, formed by joining the upper enveloping cover (7) and the base side section (8).

Two pieces (11) are placed overlapping one on the other, along the edges (e) maintaining both greater bases (BM) at the same end and proceed to weld by hot air or ultrasound the sides (e) of each piece. When encountering the curved parts, the same overlapping width is maintained (S), along the side defined by the inner distance (c), (b) and (a).

The cavities (cv) of each side face each other and overlap, as well as the convex portions of each edge at the height of the maximum distance (b), defining the overlapping region (S). At this point, the canvas is manipulated according to the curves, so that the overlapping (S) is always the same along the all the sinusoidal region of each piece (11), providing a constant shape to the curve of the enveloping cover (7).

The perspectives of Figures 23 and 24 precisely show how they are overlapped and welding the different pieces (11), according to the above described. Figure 23 is a perspective of transparent lines, showing the overlapping regions (S) and how the enveloping upper cover (7) of the alternative embodiment is folded. Instead Figure 24 is a full-lined perspectives describing how two pieces (11) already welded remain and with the curves formed to achieve the enveloping effect required. The folding of the edge (a) of the enveloping cover (7) is performed to generate an adjustment nerve, which assures that the covering cannot be removed while the inflatable ring or tube (9) is completely pumped, the interior air uniformly exerting sufficient pressure on the entire enveloping cover (7) surface (17a).

Figures 25 and 26 complete the disclosure by a front perspective of two welded pieces (11) and manipulated curves thereof (Figure 25) and a side perspective of a single piece (11) showing the base side section (8) and the curvature acquired by the enveloping cover (7), from the welding and overlapping performed (Figure 26).

The same process must be repeated with each piece (11) till finishing forming the canvas pool (6) with interchangeable inflatable tube (9) and the enveloping upper cover (7) of the alternative embodiment of the present invention.

Once the alternative embodiment of the canvas pool (6) is manufactured and sent to the user, it is worth highlighting the necessary steps for assembling the same, which are detailed in the sequence of Figures 27 to 34.

The user will separately receive, folded the canvas pool (6) and the deflated inflatable ring or tube (9). Figure 27 shows how the user will position the pool (6) where it is to be used and will unfold the side walls of the pool according to the succession of welded side sections (8) and the corresponding enveloping cover (7) sections in the upper section thereof. Next, should unfold the inflatable ring or tube (9) and proceed to pump it with the pump, such as shown in Figure 28.

Once the inflatable ring or tube (9) has been moderately pumped, the user will place on the attachment area of the side sections (8) and the enveloping upper cover (7), such as plotted in Figure 29. This process can be performed both with the pool empty as well as full. In figure 33 a half-filled pool has been graphed with a sufficient volume of water to shape the canvas pool (6).

Once the inflatable ring or tube (9) has been placed, the user must completely cover it with the enveloping upper cover (7). For that, must insert the pumping valve (v) provided in the inflatable ring or tube (9) through the whole (O) of the enveloping upper cover (7) such as illustrated in Figures 30 and 31 , and then continue to cover the inflatable ring or tube (9) with the enveloping upper cover (7), according to the sequence shown in the following Figures 32 and 33. In the latter, covering with the enveloping cover has been completely performed, while the pool is being filled and finish pumping the inflatable ring or tube (9) through the pump, causing the pressure of the air to uniformly be forced on all the external surface of the enveloping cover (7), generating that it close around the inflatable ring or tube (9) without being possible to remove it, due to the continuous pressure all along the inflatable ring or tube (9).

Final Figure 34 illustrates the canvas pool (6) of the alternative embodiment in a position to be used, full of water and with the inflatable ring or tube (9) completely pumped.

Should it be punctured and having to change it for a new one, the user will only have to remove the punctured tube and install a new inflated one, following the steps described in sequence Figures 27 to 34.

Removing the damaged inflatable tube (9) can be easily done, as what keeps it in position is the pressure exerted by the inner air. Once said tube (9) is punctured and lose the air, there will not be any pressure P against the walls of the enveloping upper cover (7), and hence, removing the punctured tube will be simply performed lifting the enveloping upper cover (7) and removing the punctured tube (9), having no air inside.

It is undoubtable that the present invention put into practice could include amendments as to construction details and shape, without this implying straying from the basic principles that are clearly supported in the following claims.