INFLATABLE ASSEMBLY AND METHOD FOR MANUFACTURED AN INFLATABLE ASSEMBLY

Abstract

Inflatable assembly (1) comprising a tubular textile support (10) made of seamless fabric, said support being coated with a layer of thermoplastic polymer material and being closed at its ends (3, 4) so ​​as to obtain a chamber airtight to an inflation gas, in which the walls (7) of said chamber have a surface density of less than 1000 g / m². Figure for the abbreviation: Fig. 2

Description

Title of the invention: INFLATABLE ASSEMBLY AND METHOD FOR MANUFACTURED AN INFLATABLE ASSEMBLY

[0001] The present invention relates to the field of inflatable assemblies used in inflatable structures, structures of the type comprising at least one inflatable assembly forming a beam which makes up the framework of inflatable enclosures, shelters or tents when the framework is covered with a canvas, or structures of the type comprising one or more inflatable assemblies assembled together and used in the manufacture of furniture or floating objects.

[0002] In the field of inflatable structures, inflatable beams of the type comprising a fabric envelope enclosing an inflatable tube are known. The inflatable tubes are generally tubular in shape and equipped with inflation valves. Such a tubular tube is obtained by winding a film of a polymer material onto itself, then joining the two longitudinal edges with a longitudinal weld to obtain an open tube, followed by two welds at the ends to close the tube. After inflation, the tubes function as beams, providing stiffness to the framework. An inflatable structure is obtained by making a textile envelope by cutting it according to a given pattern, then sewing the edges of the fabric to give it a tubular shape, followed by sewing several tubular envelopes together to obtain the desired shape, for example, an arch or a crossbeam.Several pre-made tubular tubes are inserted inside the fabric envelope thus created, which stiffens as the tubes are inflated. These structures are very lightweight yet sufficiently rigid once inflated. The inflation pressure is generally between 0.1 and 0.5 bar, and most often between 0.2 and 0.35 bar.

[0003] Self-supporting inflatable enclosures are known from documents FR3069001 or FR3092126. These enclosures have a structure comprising beams and struts that support a cover separating the inner part of the enclosure from the outside. Such enclosures are very lightweight, generally made of flexible materials, and their manufacture requires particular attention to the variations in shape and dimensions of their geometry, due in particular to manufacturing tolerances. It has thus been found that the sewing operations are not only very time-consuming and labor-intensive, but are also a source of manufacturing defects.

[0004] US patent 2011 / 253184 is also known, describing an inflatable tent made of a very lightweight fabric. According to this patent, the adjacent edges of the tent fabric are folded over each other and welded to create air channels that, when inflated, form the tent's arches. To make the air passages airtight, the walls of the air channels are coated with a certain thickness of airtight material. However, the resulting air channels are quite small in diameter, which limits their range of applications. Furthermore, manufacturing the air channel requires prior operations such as cutting the fabric, assembling its edges, and welding, in addition to coating, operations that lead to high manufacturing costs.

[0005] An objective of the invention is to remedy the drawbacks of the aforementioned documents and to provide an original solution for the production of an inflatable assembly made in an economical manner, while being reliable in operation, and capable of being inflated to high inflation pressures.

[0006] This objective is achieved by the invention which proposes an inflatable assembly comprising a tubular textile support made of a seamless fabric, said support being covered with a layer of coating in a thermoplastic polymer material and being closed at its ends so as to obtain a chamber airtight to an inflation gas, in which the walls of said chamber have a surface density of less than 1000g / m2.

[0007] In other words, the invention provides an inflatable assembly made from a seamless tubular fabric support, which ensures the mechanical properties of the assembly. This support is coated with a thermoplastic polymer material that protects the fabric fibers of the support and ensures airtightness against the inflation gas. Such inflation gas can be an inert gas, such as nitrogen, or air. The two opposite ends of the support are sealed by gluing or welding so as to remain airtight under the pressure of the inflation gas. According to an advantageous aspect of the invention, the fibers used to make the fabric support are very fine and strong yarns, and the coating layer is very thin, so as to obtain an inflation assembly in the form of a single chamber, therefore without an additional internal chamber, and whose walls have a surface density of less than 1000 g / m² and preferably between 750 and 920 g / m².

[0008] Thus, it was found, after laboratory tests, that such an inflation assembly could withstand high inflation pressures while being very lightweight, with a reduced weight compared to coated hoses, such as fire hoses. The inflation pressure can reach 5 x 10⁵ Pa (5 bar) with virtually no loss of seal.

[0009] This results in a simplified inflation assembly, as it no longer includes an internal air chamber or an external casing sewn around it. The resulting inflation assembly is more robust because critical areas exposed to the risk of leakage or tearing have been eliminated, while still being able to withstand high inflation pressures and being easier to manufacture and use.

[0010] Another advantage resulting from the elimination of seams is an improved aesthetics of the inflation assembly of the invention.

[0011] The average thickness of said coating layer may be between 0.4 and 0.8 mm and may preferably be equal to 0.6 mm.

[0012] The Young's modulus of the fabric of said support can be approximately 500 MPa. The Young's modulus is measured in the warp and weft directions of the textile fabric according to the test procedure described by ISO 13934-1.

[0013] Said fabric may comprise warp yarns and weft yarns of a material selected from: polyester, polyamide, polyethylene, said material preferably being polyester. These yarns thus have very high tenacity and can advantageously be used to produce a weft with a low basis weight.

[0014] The basis weight of said fabric may be between 300 and 600 g / m², preferably between 350 and 500 g / m², and even more preferably it may be approximately 440 g / m². Such a fabric is sufficiently dense to withstand the tensile mechanical stresses of the inflation gas.

[0015] The material used for the coating layer can be thermoplastic polyurethane, preferably based on polyether polyols. Such a material exhibits good adhesion to the substrate fabric and has excellent resistance to microbiological and fungal attacks that may be caused by microorganisms present in the blowing gas.

[0016] The chamber may include an inflation valve mounted in a sealed manner on the coated fabric of the chamber wall. This allows for easy inflation and deflation of the sealed chamber.

[0017] An inflatable assembly according to any one of the preceding claims, characterized in that said chamber can be inflated up to 5 x 10⁵ Pa (5 bar). This results in an inflatable assembly without an internal chamber, which is ultralight and can be inflated to high pressures, substantially without loss of airtightness.

[0018] The objective of the invention is also achieved with a method for manufacturing an inflatable assembly, characterized in that it comprises the following steps in order: a) production of a seamless tubular textile support by circular weaving, b) coating by extrusion of a layer of thermoplastic polymer material of the support produced in the previous step, c) turning over the coated support from the previous step, and d) closing the ends of said support after providing for the installation of an inflation valve.

[0019] The process of the invention may include an additional step c'), prior to step d), of inflating the coated support obtained in step c) with steam.

[0020] In a variant of the process, a thermoforming step of the inflatable assembly can be added so as to imprint it with an arch shape.

[0021] Step d) of the process of the invention can be carried out by welding the ends of the inflatable assembly. The ends of the inflatable assembly are welded by HF or ultrasonic welding.

[0022] The invention will be better understood from the following description, which is based on the following figures: Fig. 1 is a schematic perspective view of an inflatable structure for an inflatable enclosure of a known type; [Fig.2] is a perspective view of an inflatable assembly of the invention; [Fig.3] is one of the coated support which makes up the inflatable assembly of the invention during its manufacture; Figure 4 illustrates the steps in the manufacturing process of an inflatable assembly of the invention; and Figure 5 schematically illustrates the steps of the process of the invention according to another embodiment.

[0023] In the various figures, identical or similar elements bear the same reference. Their description is therefore not systematically repeated.

[0024] Figure 1 illustrates an inflatable structure 100 of the prior art, which in this example is an inflatable enclosure comprising a frame 101 made from several inflatable tubes of the prior art. The inflatable tubes have a generally tubular shape and are made from an airtight film through successive manufacturing and assembly operations to form an airtight air chamber. After manufacturing, the inflatable tubes are inserted into a textile envelope. The textile envelope can contain one or more inflatable tubes and is made by sewing to take the shape of an element of the enclosure's frame, such as a beam, an arch, or a crossbeam.

[0025] Figure 2 illustrates an inflatable assembly 1 according to the invention. It comprises a tubular textile support 10 coated with a layer of thermoplastic polymer material on the inner face of its walls 7, as will be detailed later. The support 10 has an elongated shape and is hermetically sealed at its ends 3 and 4, for example using a bonding device 40. The hermetically sealed support can be achieved by depositing a layer of adhesive between the end walls of the support 10, The walls are clamped between two parallel flat jaws 41, 42 and tightened using screws 43. Bonding can be done cold, using an airtight and watertight polymer adhesive, such as TEC7® MS polymer-based adhesive. This creates a chamber that is airtight against inflation gas. An inflation valve 5, which also allows deflation, completes the inflation assembly 1. The inflation valve 5 is mounted airtight onto the coated fabric of the chamber wall. For this purpose, the inflation valve 5 is bonded, for example, using an adhesive of the type described above, or it is welded using HF or ultrasonic welding to the walls of the support 10 so as to allow inflation of the assembly from the outside, using a pump or compressor.

[0026] In one embodiment of the invention, the ends 3 and 4 of the support 10 are welded, for example, using HF or ultrasonic welding.

[0027] Figure 3 illustrates a tubular textile support 10 coated with a layer 20 of a thermoplastic polymer coating, part of which has been lifted using a peeling clamp 30 to reveal the weave underneath. The support 10, open at its ends 3 and 4, has a substantially cylindrical shape with an annular cross-section about an axis of revolution X-X'.

[0028] The weave structure was obtained by weaving warp yarns 15 (these are yarns oriented longitudinally) and weft yarns 16 (these are yarns oriented transversely).

[0029] In the described example, the warp yarns 15 and weft yarns 16 are high-tenacity filament polyester (PET) yarns. High tenacity refers to yarns with higher mechanical strength and better long-term resistance to harsh external / environmental conditions: pH, humidity, temperature, and weather. In particular, high-tenacity PET yarns are less sensitive to humidity and aging because they have a higher number-average molecular weight (Mn) and fewer carboxyl groups at the end of the chain (CEG) than conventional 'low-tenacity' PET yarns. To obtain the lowest possible basis weight (grams per square meter), the weaving is carried out with very fine warp and weft yarns. Therefore, PET warp yarns 15 with the following technical characteristics are preferred: 2200 dtex, 100z twist, and 478 double ends (pairs).We prefer to use 16-ply PET weft yarns with the following technical characteristics: 2200 dtex, 40z twist, 70 yarns / 10cm.

[0030] As seen in [Fig. 3], the weave is of the plain weave type, obtained by inserting alternating weft yarns 16 over warp yarns 15 to obtain the same sides on the right and wrong sides. This type of weave exhibits the greatest number of interactions between the warp and weft yarns and is quite uniform, even quite smooth on the surface. The weave obtained by weaving the warp yarns 15 and the weft yarn 16 of the described example has an average thickness of about 0.45 mm and a weight per unit area (or basis weight) of about 440 g / m2.

[0031] The weave of the support 10 of the invention was obtained by circular weaving of the warp 15 and weft 10 yarns using a circular weaving machine, for example of the HM604 type from the company MANDALS®.

[0032] The resulting armor is then coated with a layer 20 of a coating, preferably thermoplastic polyurethane (TPU), and more preferably TPU based on polyether polyols. This material exhibits very good adhesion properties to the woven reinforcement of the support 10 and forms a good barrier to inflation gases (it has a low air permeability factor of approximately 0.5 m³ / h / m²). Furthermore, this material exhibits excellent resistance to microbiological and fungal attack. Such a material has a Shore A hardness of approximately 86-88. The thickness of the coating layer 20 is approximately 0.6 mm. The density of the coating layer 20 is approximately 1.12 g / cm³.

[0033] We will explain with reference to [Fig.4] the steps of the manufacturing process of an inflatable assembly 1 of the invention.

[0034] The first manufacturing step is circular weaving a) of warp yarns 15 and weft yarns 16 on a circular loom. This produces a tube of predetermined length and diameter, which is then subjected to a coating step b). Step b) is carried out by extruding a thin layer of TPU onto the flattened tube obtained in step a), with the tube in its right-side-out position. The tube from step b) is then inverted, resulting in an upside-down tube, so that the coating layer 20 is located inside the tube after it has been inverted. This produces a support 10 that provides a good seal against the inflation gas while preventing any delamination, for example by abrasion, of the coating layer 20. The inflation valve can then be glued or welded, and the ends 3 and 4 of the support 10 can be sealed airtight.

[0035] In a preferred embodiment of the invention, the coated and inverted tube obtained in step c) is subjected to a steam inflation operation at a temperature of approximately 130-140°C and a pressure of approximately 2 bar for a period of approximately 10 minutes. This allows the coated tube to regain its diameter, following the contraction it underwent during the extrusion step b). As a result of this operation, the diameter of the tube increases by approximately 10 to 12%, and the coating layer 20 stretches and becomes uniform, resulting in a surface density of approximately 950 to 1000 g / m².

[0036] Next, the inflation valve is added and the ends of the support are sealed to obtain an inflation assembly 1.

[0037] By way of example, an assembly 10 thus obtained has a diameter of approximately 250 mm and can be inflated up to 5 x 105 Pa (5 bars) without loss of sealing.

[0038] Figure 5 illustrates an additional operation of the process for obtaining an inflatable assembly 1 of the invention. More precisely, it is a thermoforming operation of the inflation assembly 1 obtained as previously described.

[0039] Thus, the thermoforming process begins with step i) heating the inflatable assembly 1 to a temperature of approximately 100°C while it is held flat, or on a support arranged in an axial direction, held at each end by a clamp 50. By axial direction, we mean the direction substantially parallel to the axis of revolution X-X' of the support 10 of the inflation assembly. In step ii), the support 10 is then fixed with its clamps 50 onto a rounded block 52. In step iii), the support 10 is subjected to inflation using steam at a temperature of approximately 130-140°C and a pressure of approximately 2 bar for a period of approximately 10 minutes. This allows the support 10, and therefore the inflation assembly, to take on the arched shape illustrated in step iv). An inflation assembly 1' in the shape of an arch thus obtained exhibits improved rigidity compared to the arches of the framework 110 of the [Fig.l] of the prior art.

[0040] The inflation assembly 1,1' according to the invention can be used to construct the framework of an inflatable enclosure, for example of the type illustrated in [Fig.1], in a more economical way, with fewer components and less labor for the manufacture and assembly of these components, while giving more rigidity to the framework.

[0041] Other variations and embodiments of the invention can be envisaged within the scope of the invention as claimed. Thus, the ends of the inflation assembly 1 can take other shapes than that illustrated, for example a curved shape or a flat shape.

Claims

Demands

1. Inflatable assembly (1, 1') comprising a tubular textile support (10) made of seamless fabric by circular weaving, said support being covered with a layer (20) of coating in a thermoplastic polymer material and being closed at its ends (3, 4) so ​​as to obtain a chamber airtight to an inflation gas, in which walls (7) of said chamber have a surface density of less than 1000g / m2.

2. Assembly according to claim 1, characterized in that the average thickness of said coating layer (20) is between 0.4 and 0.8 mm and is preferably equal to 0.6 mm.

3. Assembly according to any one of the preceding claims, characterized in that the Young's modulus of the fabric of said support is about 500MPa.

4. Assembly according to any one of the preceding claims, characterized in that said fabric comprises warp yarns (15) and weft yarns (16) of a material selected from: polyester, polyamide, polyethylene and the material is preferably a polyester.

5. Assembly according to any one of the preceding claims, characterized in that the basis weight of said fabric is between 300 and 600 g / m2, preferably between 350 and 500 g / m2.

6. Assembly according to any one of the preceding claims, characterized in that said thermoplastic polymer material is thermoplastic polyurethane, preferably based on polyether polyols.

7. Assembly according to any one of the preceding claims, characterized in that said chamber comprises an inflation valve (5) mounted in a hermetically sealed manner on the coated fabric of the wall (7) of the chamber.

8. Inflatable assembly according to any one of the preceding claims, characterized in that said chamber is capable of being inflated up to 5 x 105 Pa (5 bars).

9. A method for manufacturing an inflatable assembly (1,1') characterized in that it comprises the following steps in order: a. production of a seamless tubular textile support (10) by circular weaving, b. coating by extrusion of a layer (20) of thermoplastic polymer material of the support made in the previous step, c. turning over the coated support from the previous step, and d. closing the ends (3, 4) of said support after providing for the installation of an inflation valve.

10. Method according to the preceding claim, characterized in that it comprises an additional step c'), prior to step d), of inflating with water vapor the coated support obtained in step c).

11. A method according to any one of claims 9 or 10, characterized in that it comprises a thermoforming step of the inflatable assembly so as to imprint it with an arch shape.

12. A method according to any one of claims 9 to 11, characterized in that step d) is carried out by welding the ends (3, 4) of the inflatable assembly.

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