INFLATABLE MAST FOR AN INFLATABLE STRUCTURE

Abstract

Inflatable vertical mast (8) with captive air for an inflatable structure (2), the mast having a longitudinal axis (3) and in which a plurality of inflatable elongated elements (18) of revolution with captive air are arranged in the circumferential direction around the mast (8), said elongated elements (18) each comprising at least one first tubular segment (20) extending along said mast (8) over a length (L), the first tubular segments (20) of the elongated elements (18) being arranged so that each first tubular element (20) is in contact with the adjacent first tubular elements (18) and with the periphery of the mast (8) over at least a part of said length (L). Figure for abstract: Fig. 2

Description

Title of the invention: INFLATABLE MAST FOR AN INFLATABLE STRUCTURE

[0001] The present invention relates to the field of inflatable structures, more particularly of the type comprising captive air inflatable chambers or tubes forming part of the framework of the inflatable structure comprising for this purpose an assembly of at least two inflatable tubes.

[0002] In particular, the invention relates to an inflatable mast forming a support for an inflatable structure of the type stretching vertically from its base.

[0003] In this field, enclosures are known comprising a framework made by an assembly of inflatable tubes connected together and provided with access to an inflation fluid, such as an inflation valve. After inflation, the tubes ensure the stiffening of the framework. These structures are generally self-supporting; once inflated, they maintain their shape and support coverings or doors, in the case of enclosures or shelters, or they support other elements belonging to the structure of which they are a part.

[0004] The problem that arises with inflatable structures that have large vertical dimensions such as a parasol, an umbrella or a totem, inflatable structures that are designed so that they can be completely deflated for storage, is the holding of the structure around a central inflatable tube forming a central trunk. This inflatable tube or central trunk must withstand the mechanical stresses undergone by the inflatable structure and this either under normal load (for example compression and buckling stresses in the absence of parasitic phenomena, such as those due to the weather) or when the weather conditions (wind, rain, hail, etc.) induce additional mechanical stresses which, most of the time, are supported by the central trunk.

[0005] Furthermore, in the case of parasols or umbrellas, which include a fabric-based canopy extending around the central trunk, the radial dimension of the canopy may also be significant. A trunk of large diameter would then be necessary to support the canopy and the mechanical stresses induced by it. However, it is known that the pressure of such inflatable tubes decreases with their diameter, which presents the risk of having to inflate such a trunk to an inflation pressure that is too low, not high enough for it to have the necessary rigidity to support the structure.

[0006] One objective of the invention is to remedy at least one of these drawbacks.

[0007] This objective is achieved by the invention which provides a captive air inflatable vertical mast for an inflatable structure, the mast having a longitudinal axis and in which a a plurality of captive air inflatable revolution elongated elements are arranged circumferentially around the mast, said elongated elements each comprising at least one first tubular segment extending along said mast over a predetermined length, the first tubular segments of the elongated elements being arranged such that each first tubular element is in contact with adjacent first tubular elements and with the periphery of the mast over at least a portion of said length.

[0008] By captive air inflatable mast or captive air inflatable elongated element of revolution it is understood that the mast or the inflatable element are each made in the form of a flexible envelope impervious to the inflation fluid. Such a waterproof envelope may be an impregnated fabric impervious to the inflation fluid. In a preferred embodiment of the invention, the flexible envelope impervious to the inflation fluid is an assembly comprising an external structural envelope, for example made of fabric, enclosing an air chamber or flexible inflatable tube impervious to the inflation fluid, in this case airtight. The waterproof envelopes or the inflatable tubes are provided with access to an air inlet, for example an inflation valve which can be closed after inflation. After inflation, the waterproof envelope or the fabric envelope stiffens and provides the necessary rigidity to the structure.

[0009] According to the invention, there is provided a vertical inflatable mast made in such a way that the inflatable mast is surrounded circumferentially over at least a part of its length, and preferably over at least a part of its length from its base, by several tubular inflatable segments which are all in contact with each other in the circumferential direction and all coming into contact with the periphery of the mast. Said tubular inflatable segments come into contact with each other and with the mast over at least a part of their length, preferably over their entire length. In a variant, the vertical mast may comprise several of these first inflatable tubular segments arranged at different locations along its height. In yet another variant, the mast may comprise these first inflatable tubular segments over its entire height.Such an arrangement of several peripheral tubular segments around the mast forms a support for the inflatable vertical mast which is therefore able to withstand significant mechanical stresses without buckling or bending.

[0010] Indeed, thanks to this arrangement of captive air inflatable segments around a captive air inflatable vertical mast, in which each tubular segment has three support points, one on the mast and two with the neighboring segments, it is possible to obtain a compact assembly with an increased cross-section of the support part of the inflatable structure. Indeed, the first tubular segments coming into contact with each other and with the periphery of the mast when they are inflated, we thus obtain an assembly forming a column of larger section, its value being the sum of the unit sections of the tubular segments and that of the mast. This produces an inflatable support assembly capable of being inflated to a high working pressure, higher than that of a single inflatable tube of equivalent diameter. Thus, for tubular segments of circular section surrounding a vertical tubular mast of circular section, the working (or inflation) pressure of each of the tubular elements and of the mast is therefore limited by their respective diameter and not by the diameter circumscribed by the elements forming the support column, if a single inflatable tube of equivalent diameter had been used, each of these elements having three support points with its neighbor.

[0011] Furthermore, by producing the first tubular segments, forming a support column for the mast of the invention, by assembling several inflatable elements, each segment can be inflated to a pre-established pressure, by connecting it to a pressure source, the inflation pressures of different segments and that of the mast being able to vary from one to the other.

[0012] Said first tubular segments and said mast may be held together using at least one link. Thus, the links at the points of contact between the first inflatable tubular segments and the inflatable mast make it possible to transmit shear forces into the support and thus significantly increase the bending resistance capacity of the entire mast and column and consequently of the entire inflatable structure.

[0013] In an alternative embodiment of the invention, said link may be a peripheral band which surrounds said first tubular segments. Said band may have a width ranging from a few tens of mm and up to a width equal to the length L of said first tubular segments. Thus, the elements are kept in contact using a force exerted radially from the outside towards the central axis of the mast.

[0014] In another alternative embodiment of the invention, said link is a first fixing device arranged at the contact points of said first adjacent tubular segments.

[0015] In yet another alternative embodiment of the invention, said link is a second fixing device arranged at the contact points of said mast and said first tubular segments.

[0016] The tubular segments and the mast are thus made integral over their common length, by at least one link which may be a rigid link or a flexible link chosen from: a flexible or rigid strip, a glue, a seam, an assembly with VELCRO® type gripping strips. In a preferred embodiment of the invention, the combination of all the links mentioned is used, in particular at least one peripheral strap combined with the fixing devices produced using the first and second fixing device to obtain a maximum optimized bending resistance capacity of the structure.

[0017] At least three elongated elements each comprising a first tubular segment can be arranged around the mast. The mast is thus surrounded by three tubular segments, which ensures a minimum of contact points between the first tubular segments and the mast to obtain reinforced mechanical resistance of the assembly.

[0018] In a variant of the invention, at least six elongated elements each comprising a first tubular segment can be arranged around the mast. This makes it possible to better distribute the load over the periphery of the assembly.

[0019] In a preferred embodiment of the invention, the mast and said first tubular segments have circular sections having substantially the same diameter. This makes it easier to produce on an industrial scale the seven inflatable elements which make up the assembly formed by the mast and the column of the invention, in particular by using the same width of fabric to obtain the structural envelope of each inflatable element. Furthermore, the circumscribed diameter of the column thus obtained is in this case equal to three times the unit diameter of an inflatable element of the assembly.

[0020] In another embodiment of the invention, the mast and said first tubular segments have circular sections, the diameter of the mast being greater than the diameter of said first tubular segments. This makes it possible to arrange several tubular segments of smaller diameter around the mast.

[0021] The object of the invention is also achieved with an inflatable structure in which the mast projects vertically relative to said first tubular segments of the elongated elements and in that at least a portion of the elongated elements comprise second tubular segments projecting transversely relative to said mast.

[0022] The structure may comprise at least one protective canvas attached to the second tubular segments of said elongated elements. Such an inflatable structure can provide protection against weather factors (sun, rain, hail, etc.) over a fairly large area below the protective canvas, because the assembly formed by the mast and its support column is very strong and can withstand significant mechanical stresses, while being able to be deflated and stored at any time.

[0023] The invention will be better understood thanks to the rest of the description, which is based on the following figures: [Fig.l] is a perspective view of an inflatable structure comprising an inflatable mast according to the invention; [Fig.2] is a perspective view of the inflatable mast of [Fig.l]; [Fig.3] is a perspective view of a peripheral element of the inflatable mast of [Fig.2]; [Fig.4] is a perspective view of a central element of the inflatable mast of [Fig.2]; Figures 5a to 5g illustrate by sectional views the different variant embodiments of the inflatable mast of the invention; [Fig.6] represents a schematic view of another alternative embodiment of the invention.

[0024] In the various figures, identical or similar elements bear the same reference. Their description is therefore not systematically repeated.

[0025] [Fig.l] schematically represents an inflatable structure 2 of the inflatable sun protection parasol type mainly comprising a vertical inflatable mast 8 with captive air of longitudinal axis 3 and a canopy 10. The mast 8 rests on the ground and rises vertically above the canopy 10. Inflatable members 4 are arranged at a certain height from the ground around the mast 8 and support the canopy 10.

[0026] As seen in [Fig.l], the inflatable members 4 project radially relative to the vertical mast 8, the longitudinal axis of a member forming a right angle with the axis 3 of the mast 8. The members 4 are distributed regularly in the circumferential direction around the mast and are capable of supporting the canopy 10. The members 4 are held in a substantially horizontal plane using a plurality of shrouds (not shown) fixing them to the vertical mast 8.

[0027] The canopy 10 of the inflatable structure 2 comprises one or more canvases 16 fixed between two successive frames 4 in the circumferential direction, or a single canvas 16 of the desired shape can be fixed on the frames 4. The canvas can be an openwork fabric to let the wind through, when the structure serves as sun protection, or an oilcloth, or even reinforced when it serves as protection against bad weather. The canopy 10 can have a circular shape as shown in [Fig.l], or it can have another shape, for example oval, hexagonal, square, rectangular.

[0028] In the illustrated embodiment, the inflatable structure 2 comprises six members 4, thus making it possible to better distribute the load circumferentially, for example that of the weight of the canopy 10 and the stresses to which it is subjected in the event of weather hazards.

[0029] According to the invention, the captive air inflatable vertical mast 8 is surrounded by a plurality of captive air inflatable elongated elements 18 of revolution, arranged in the circumferential direction around the mast, these elongated elements 18 each comprising at least one first tubular segment 20 extending along said mast 8 over a predetermined length L, the first tubular segments 20 of the elongated elements 18 being arranged so that each first tubular element 20 is in contact with the first tubular elements 18 adjacent and with the periphery of the mast 8 over at least part of said length L.

[0030] An inflatable structure 2 is thus obtained in which the mast 8 is produced at least over part of its length in the form of an assembly 1 formed by the arrangement of the plurality of first tubular segments 20 around the mast 8 over a predetermined length L thereof.

[0031] As best seen in [Fig.l], the inflatable structure 2 comprises a plurality of elongated inflatable elements 18 of revolution with captive air regularly spaced in the circumferential direction, here six in number.

[0032] The elongated elements 18 each comprise a first tubular segment 20 extending vertically along the vertical mast 8 of the inflatable structure 2 and a second tubular segment 22 extending radially projecting relative to the vertical mast 8 of the inflatable structure 2 so as to form a frame 4. The first tubular segments 20 are made so that each is in contact with the two elongated elements 18 which are directly adjacent to it in the circumferential direction. Each elongated element 18 also comprises a folding segment 24 connecting the first and second tubular segments 20, 22 of the elongated element 18. The first tubular segments 20 of the elongated elements 18 are, in the example illustrated, cylinders arranged with their longitudinal axes parallel to the axis 3 of the mast 8. The second tubular segments 22 may have a section identical to the first or different from them.

[0033] Each elongate element 18 of captive air inflatable revolution is composed of a plurality of internal air chambers and an external structural envelope inside which the internal air chambers are housed, the external envelope being formed of the first and second tubular segments 20, 22 and the folding segment 24.

[0034] The outer casing of the captive air inflatable elongated elements 18 of revolution is made from a fabric, for example DACRON®. Each internal air chamber of the captive air inflatable elongated elements 18 of revolution is formed from an extensible material, for example polyurethane. The internal air chambers form the framework of the captive air inflatable elongated elements 18 of revolution. In the example illustrated in the figures, the internal air chambers are made so as to communicate with each other, at least one being connected to an inlet for an inflation fluid via an inflation valve (not shown). When the inflation valve receives the inflation fluid, which in this example is air from a pressurized air source, the internal chambers of the elongated element 18 are inflated simultaneously. Each elongated element 18 is thus inflated independently by connecting the inlet of one of its chambers to a pressurized air supply.

[0035] Of course, it is also possible to provide each air chamber of each elongated element 18 with its own inflation valve and thus to inflate each air chamber independently of the neighboring air chambers.

[0036] The captive air mast 8 of the inflatable structure 2 is produced in a similar manner, by introducing one or more expandable polyurethane air chambers into an external structural fabric envelope, made for example of DACRON®. The internal chamber(s) of the mast 8 communicate with each other and are connected via an inflation valve (not shown) to a pressurized air inlet. During inflation, the air chambers stiffen and form the framework of the mast, giving it the necessary rigidity. The mast 8 has the shape of a tubular barrel with a circular section in the example shown in the figures. In other variants (not shown), the section of the mast 8 may have another shape, for example square, rectangular, hexagonal.

[0037] Advantageously, the first tubular segments 20 have circular sections and are tangent to each other and tangent to the mast 8 also having a circular section over the entire length L of the first tubular segments 20, they are held together in this position using at least one link. [Fig.2] illustrates several links which are: a peripheral band 30 which surrounds the periphery of the column of the assembly 1 and keeps the first tubular segments 20 tight to each other and against the mast 8. In this example, first fixing devices 32 (schematically represented by squares in the figures) are arranged between the directly adjacent first tubular segments and second fixing devices 34 (schematically represented by triangles in the figures) are arranged between the mast 8 and the first tubular segments 20.The first and second fixing devices 32 and 34 are chosen from: gluing, sewing, VELCRO® type self-gripping strips sewn to the outer casing in at least one point, preferably in several points or even more preferably continuously over the entire length of the first tubular segments 20. [Fig. 3] schematically represents a tubular segment 20 provided with two first fixing devices 32 and a second fixing device 34 over its entire length. [Fig. 4] schematically represents the part of the mast 8 intended to be surrounded by the first tubular segments 20 provided with second fixing devices 34 over the entire length of said part.

[0038] In an advantageous variant of the invention, as better seen in [Fig. 6], the mast 8 and the first tubular segments 20 are held in contact at the points of tangency over their length L using a clamping band 30 which is produced in the form of a cylindrical sleeve extending substantially over the length L of the assembly 1. Such a cylindrical sleeve can be produced from a strip of fabric, for example DACRON®, a strip which extends longitudinally forming fabric turns at its edges, the adjacent fabric turns being sewn together by at least one seam 31 extending helically along the cylindrical sleeve. The cylindrical sleeve or tightening strip 30 ensures external hooping of the assembly 1 formed by the mat 8 and the first tubular segments 20 surrounding it to form a support column, which provides good bending rigidity of the assembly thus obtained. Of course, the external cylindrical tightening sleeve according to the variant of [Fig.6] can be the only link which holds the assembly or it can be used in combination with the first fixing devices 32 and / or with the second fixing devices 34.

[0039] Figures 5a to 5g illustrate by means of schematic cross-sectional views different variant embodiments of the invention.

[0040] [Fig.5a] illustrates a first variant in which the first tubular elements 20 and the mast 8 all have circular sections having the same diameter. The first tubular segments 20 are fixed to each other using first fixing devices 32 and to the mast 8 using second fixing devices at their points of tangency. The assembly thus obtained further comprises a peripheral fixing strap 30, several peripheral straps 30 being able to be arranged along the length of the assembly 1. This solution has the greatest resistance to mechanical stresses, while being produced with inflatable objects having the same diameter, therefore more easily manufactured.

[0041] [Fig.5b] illustrates a second variant embodiment in which the first tubular segments 20 and the mast 8 all have circular sections having the same diameter and they are held together by a peripheral strap 30, or several peripheral straps 30 which can be arranged along the length of the assembly 1. For example, the diameter of the segments 20 and the mast 8 is approximately 150 mm and therefore the diameter formed by their assembly, or circumscribed diameter of the assembly 1, is approximately 450 mm, the inflation pressure of each of their captive air chambers being able to go up to 0.8 bar (8 x 104 Pa), whereas a single tubular captive air bladder of circular section with a diameter of 450 mm could only support a pressure of a maximum of 0.25 to 0.3 bar (2.5 to 3 x 104 Pa).

[0042] [Fig. 5c] illustrates a variant in which the first tubular segments 20 and the mast 8 all have circular sections, but where the diameter of the mast 8 is greater than that of the first tubular segments 20. The first tubular segments 20 are fixed to each other using first fixing devices 32 and to the mast 8 using second fixing devices 34 at their points of tangency. The assembly 1 thus obtained further comprises at least one peripheral fixing strap 30. As for example, for a variant in which the mast 8 comprises 12 adjacent first tubular segments coming into contact with each other and with the periphery of the mast, the diameter of the first segments 20 is 96 mm, the diameter of the mast 8 is 275 mm and therefore the diameter formed by their assembly, or circumscribed diameter of the assembly 1, is approximately 467 mm. In this variant, the mast 8 can be inflated up to 0.45 bar (4.5 x 104 Pa), the inflation pressure of each of the captive air chambers of the first tubular segments 20 being able to go up to 1.3 bar (13 x 104 Pa).

[0043] [Fig.5d] illustrates a variant close to that of [Fig.5a], but in which, unlike the variant of [Fig.5a], the peripheral fixing strap 30 is absent.

[0044] [Fig.5e] illustrates a variant close to that of [Fig.5d], but in which, unlike the variant of [Fig.5d], only first fixing devices 32 are present to ensure the fixing of the first tubular segments 20 adjacent to each other.

[0045] [Fig.5f] illustrates a variant close to that of [Fig.5d], but in which, unlike the variant of [Fig.5d], only second fixing devices 34 are present to ensure the fixing of the mast 8 with the first adjacent tubular segments 20.

[0046] [Fig.5g] illustrates a variant in which the mast 8 and the first segments tubular segments 20 have circular sections, the diameter of the mast 8 being less than the diameter of the first three tubular segments 20 which surround it. The assembly thus obtained further comprises at least one peripheral fixing strap 30.

[0047] Other variants and embodiments of the invention may be envisaged within the scope of the invention as claimed. Thus, it is possible to arrange “n” first inflatable tubular segments around the inflatable vertical mast and at all height levels of the vertical mast, or even over its entire height.

Claims

Claims

1. Inflatable vertical mast (8) with captive air for an inflatable structure (2), the mast having a longitudinal axis (3) and in which a plurality of inflatable elongate elements (18) of revolution with captive air are arranged in the circumferential direction around the mast (8), said elongate elements (18) each comprising at least one first tubular segment (20) extending along said mast (8) over a length (L), the first tubular segments (20) of the elongate elements (18) being arranged so that each first tubular element (20) is in contact with the adjacent first tubular elements (18) and with the periphery of the mast (8) over at least a part of said length (L), characterized in that said first tubular segments (20) and said mast (8) are held together using at least one link (30, 32, 34) and in that said link is a peripheral band (30) which surrounds said first tubular segments (20).

2. Mast according to claim 1, characterized in that said link is a first fixing device (32) arranged at the contact points of said adjacent first tubular segments (20).

3. Mast according to one of claims 1 or 2, characterized in that said link is a second fixing device (34) arranged at the contact points of said mast (8) and said first tubular segments (20).

4. Mast according to one of the preceding claims, characterized in that at least three elongated elements (18) each comprising at least one first tubular segment (20) extend along the mast (8).

5. Mast according to one of the preceding claims, characterized in that at least six elongated elements (18) each comprising at least one first tubular segment (20) extend along the mast (8).

6. Mast according to the preceding claim, characterized in that the mast (8) and said first tubular segments (20) have circular sections having substantially the same diameter.

7. Mast according to one of claims 1 to 5, characterized in that the mast (8) and said first tubular segments (20) have circular sections, the diameter of the mast (8) being greater than the diameter of said first tubular segments (20).

8. Inflatable structure comprising a mast (8) according to one of the preceding claims, characterized in that said mast (8) projects vertically relative to said first tubular segments (20) of the elongated elements (18) and in that at least a portion of the elongated elements (18) comprise second tubular segments (22) projecting transversely relative to said mast (8).

9. Structure according to claim 8, characterized in that it comprises at least one protective fabric (16) fixed to the second tubular segments (22) of said elongated elements (18).

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