Inflatable mast for an inflatable structure

Abstract

The invention relates to a tethered-air inflatable vertical mast (8) for an inflatable structure (2), the mast having a longitudinal axis (3), wherein a plurality of tethered-air inflatable, rotationally symmetrical elongate elements (18) are arranged circumferentially around the mast (8), and wherein the elongate elements (18) each comprise at least one first tubular segment (20) extending along the mast (8) over a length (L), the first tubular segments (20) of the elongate elements (18) being arranged such that each first tubular segment (20) is in contact with the adjacent first tubular segments (18) and with the periphery of the mast (8) over at least part of the length (L).

Description

INFLATABLE MAST FOR AN INFLATABLE STRUCTURE

[0001] The present invention relates to the field of inflatable structures, more particularly of the type comprising chambers or inflatable tubes with captive air 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 that stretches vertically from its base.

[0003] In this field, we know of enclosures with a framework made up of an assembly of interconnected inflatable tubes, each equipped with an access point for an inflation fluid, such as an inflation valve. After inflation, the tubes stiffen the framework. These structures are generally self-supporting; once inflated, they maintain their shape and support roofs 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 with inflatable structures of significant vertical dimensions, such as parasols, umbrellas, or totems—structures designed to be completely deflated for storage—is ensuring the structure remains stable around a central inflatable tube that forms a core. This inflatable tube, or core, must withstand the mechanical stresses exerted on the inflatable structure, both under normal loads (for example, compression and buckling in the absence of adverse weather conditions) and when weather conditions (wind, rain, hail) induce additional mechanical stresses, which are usually borne by the core.

[0005] Furthermore, in the case of parasols or umbrellas, which include a fabric canopy extending around the central shaft, the radial dimension of the canopy can also be significant. A shaft with a large diameter would then be necessary to support the canopy and the mechanical stresses it induces. However, it is known that the pressure of such inflatable tubes decreases with their diameter, which presents the risk 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 proposes a vertical inflatable captive air mast for an inflatable structure, the mast having a longitudinal axis and in which a plurality of elongated elements of revolution inflatable captive air are arranged in the circumferential direction 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 so that each first tubular element is in contact with the first adjacent tubular elements and with the periphery of the mast over at least a part of said length, characterized in that said first tubular segments and said mast are held together by means of at least one link and in that said link is a peripheral band which surrounds said first tubular segments.

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

[0009] According to the invention, a vertical inflatable mast is proposed, constructed such that the inflatable mast is circumferentially surrounded, over at least part of its length and preferably over at least part of its length from its base, by several tubular inflatable segments, all of which are in circumferential contact with each other and all of which come into contact with the periphery of the mast. These tubular inflatable segments These segments come into contact with each other and with the mast along at least part of their length, preferably along their entire length. In one variation, the vertical mast may have several of these first inflatable tubular segments arranged at different points along its height. In yet another variation, the mast may have these first inflatable tubular segments along its entire height. Such an arrangement of several peripheral tubular segments around the mast forms a support for the inflatable vertical mast, which is thus able to withstand significant mechanical stresses without buckling or bending.

[0010] Indeed, thanks to this arrangement of inflatable segments with trapped air around a vertical inflatable mast, in which each tubular segment has three points of support—one on the mast and two with neighboring segments—a compact assembly with an increased cross-sectional area is achieved, including the support portion of the inflatable structure. As the first tubular segments come into contact with each other and with the periphery of the mast when inflated, this creates a column with a larger cross-sectional area, its value being the sum of the cross-sectional areas of the individual tubular segments and that of the mast. This results in an inflatable support assembly capable of being inflated to a high working pressure, exceeding that of a single inflatable tube of equivalent diameter.Thus, for tubular segments of circular cross-section surrounding a vertical tubular mast of circular cross-section, the working pressure (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 points of support with its neighbor.

[0011] Moreover, 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 another.

[0012] According to the invention, said first tubular segments and said mast are to be held together by means of at least one link. Thus, the links at the points of contact between The first inflatable tubular segments and the inflatable mast allow shear forces to be passed 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] According to the invention, the link is a peripheral band that surrounds the first tubular segments. This band can have a width ranging from a few tens of millimeters up to a width equal to the length L of the first tubular segments. Thus, the elements are held in contact by means of a force exerted radially from the outside towards the central axis of the mast.

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

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

[0016] The tubular segments and the mast are thus joined together along their common length by at least one connection, which may be a rigid or flexible connection chosen from: a flexible or rigid band, gluing, stitching, or a VELCRO®-type hook-and-loop fastener. In a preferred embodiment of the invention, a combination of all the aforementioned connections is used, in particular at least one peripheral strap combined with the fastening devices made using the first and second fastening devices to obtain maximum optimized flexural strength 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, ensuring a minimum number of contact points between the first tubular segments and the mast, thereby increasing the overall mechanical strength.

[0018] In one embodiment of the invention, at least six elongated elements, each comprising a first tubular segment, can be arranged around the mast. This allows for a better distribution of the load around the periphery of the assembly.

[0019] In a preferred embodiment of the invention, the mast and the first tubular segments have circular cross-sections of substantially the same diameter. This facilitates the industrial-scale production of the seven inflatable elements that comprise the assembly formed by the mast and column of the invention, particularly by using the same fabric width 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 in the assembly.

[0020] In another embodiment of the invention, the mast and the first tubular segments have circular cross-sections, the diameter of the mast being greater than the diameter of the first tubular segments. This allows several smaller diameter tubular segments to be arranged around the mast.

[0021] The objective of the invention is also achieved with an inflatable structure in which the mast extends vertically in projection relative to said first tubular segments of the elongated elements and in that at least a part of the elongated elements comprise second tubular segments extending transversely in projection relative to said mast.

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

[0023] The invention will be better understood from the following description, which is based on the following figures: Figure 1 is a perspective view of an inflatable structure comprising a mast inflatable according to the invention; Figure 2 is a perspective view of the inflatable mast of Figure 1; Figure 3 is a perspective view of a peripheral element of the inflatable mast of Figure 2; Figure 4 is a perspective view of a central element of the inflatable mast of Figure 2; Figures 5a to 5g illustrate by cross-sectional views the different variants of the inflatable mast of the invention; Figure 6 represents a schematic view of another variant of the invention.

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

[0025] Figure 1 schematically represents an inflatable structure 2 of the type inflatable sunshade comprising mainly a vertical inflatable mast 8 with captive air of longitudinal axis 3 and a canopy 10. The mast 8 is supported 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 Figure 1, the inflatable members 4 project radially from the vertical mast 8, longitudinal axis of a member making a right angle with axis 3 of the mast 8. The members 4 are regularly distributed 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 by means of a plurality of stays (not illustrated) fixing them to the vertical mast 8.

[0027] The canopy 10 of the inflatable structure 2 comprises one or more fabric panels 16 fixed between two successive frames 4 in a circumferential direction, or a single fabric panel 16 of the desired shape may be fixed to the frames 4. The fabric may be an openwork material to allow air to pass through when the structure serves as sun protection, or a waxed or even reinforced fabric when it serves as weather protection. The canopy 10 may have a circular shape as shown in Figure 1, or it may have another shape, for example, oval, hexagonal, square, or rectangular.

[0028] In the illustrated embodiment example, the inflatable structure 2 includes six members 4, thus allowing for better circumferential distribution of the load, 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 vertical inflatable mast 8 with captive air is surrounded by a plurality of elongated inflatable elements 18 of revolution with captive air, arranged in the circumferential direction around the mast, these elongated elements 18 each comprising at least a 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 adjacent tubular elements 18 and with the periphery of the mast 8 over at least a part of said length L.

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

[0031] As more clearly seen in Figure 1, the inflatable structure 2 comprises a plurality of elongated elements 18 of revolution inflatable with captive air spaced regularly in the circumferential direction, here numbering six.

[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 projecting radially from the vertical mast 8 of the inflatable structure 2 so as to form a member 4. The first tubular segments 20 are designed so that each is in contact with the two elongated elements 18 that 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 illustrated example, cylinders arranged with their longitudinal axes parallel to the axis 3 of the mast 8. The second tubular segments 22 may have the same cross-section as the first or a different cross-section.

[0033] Each elongated 18-revolution inflatable captive air element 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 by the first and second tubular segments 20, 22 and the folding segment 24.

[0034] The outer shell of the inflatable elongated elements 18 of revolution with captive air is made of a fabric, for example, DACRON®. Each internal air chamber of the inflatable elongated elements 18 of revolution with captive air is made of a stretchable material, for example, polyurethane. The internal air chambers form the framework of the inflatable elongated elements 18 of revolution with captive air. In the example shown in the figures, the internal air chambers are designed to communicate with each other, with at least one connected to an inflation fluid inlet 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 equip each inner tube of each elongated element 18 with its own inflation valve and thus inflate each inner tube independently of the neighboring inner tubes.

[0036] The captive air mast 8 of inflatable structure 2 is constructed similarly, by inserting one or more expandable polyurethane air chambers into an external structural fabric envelope, made, for example, of DACRON®. The internal chamber(s) of mast 8 are interconnected and linked via an inflation valve (not shown) to a pressurized air supply. During inflation, the air chambers stiffen and form the mast's framework, providing the necessary rigidity. Mast 8 has a tubular shaft shape with a circular cross-section in the example shown in the figures. In other (not illustrated) versions, the cross-section of mast 8 may have a different shape, for example, square, rectangular, or hexagonal.

[0037] Advantageously, the first tubular segments 20 have circular cross-sections and are tangent to each other and to the mast 8, which also has a cross-section circular along the entire length L of the first tubular segments 20, they are held together in this position by means of at least one tie. Figure 2 illustrates several ties, which are: a peripheral band 30 that surrounds the periphery of the column of assembly 1 and holds the first tubular segments 20 tightly together and against the mast 8. In this example, first fastening devices 32 (represented schematically by squares in the figures) are arranged between the first directly adjacent tubular segments, and second fastening devices 34 (represented schematically by triangles in the figures) are arranged between the mast 8 and the first tubular segments 20.The first and second fastening devices 32 and 34 are selected from: gluing, sewing, or VELCRO®-type hook-and-loop fasteners sewn to the outer casing at at least one point, preferably at several points, or even more preferably continuously along the entire length of the first tubular segments 20. Figure 3 schematically represents a tubular segment 20 equipped with two first fastening devices 32 and a second fastening device 34 along its entire length. Figure 4 schematically represents the portion of the mast 8 intended to be surrounded by the first tubular segments 20, equipped with second fastening devices 34 along its entire length.

[0038] In an advantageous embodiment of the invention, as more clearly shown in Figure 6, the mast 8 and the first tubular segments 20 are held in contact at the points of tangency along their length L by means of a clamping band 30, which is made in the form of a cylindrical sleeve extending substantially over the length L of the assembly 1. Such a cylindrical sleeve can be made from a strip of fabric, for example DACRON®, which extends longitudinally, forming fabric coils at its edges. The adjacent fabric coils are sewn together by at least one seam 31 extending helically along the cylindrical sleeve. The cylindrical sleeve or clamping band 30 provides external support to the assembly 1 formed by the mast 8 and the first tubular segments 20 surrounding it to form a support column, thus providing good flexural rigidity to the assembly thus obtained.Of course, the external cylindrical clamping sleeve according to the variant in Figure 6 can be the only link that holds the assembly together 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 variants of embodiment of the invention.

[0040] Figure 5a illustrates a first variant in which the first tubular elements 20 and the mast 8 all have circular cross-sections with the same diameter. The first tubular segments 20 are fixed to each other using first fastening devices 32 and to the mast 8 using second fastening devices at their points of tangency. The resulting assembly also includes a peripheral fastening strap 30; several peripheral straps 30 can be arranged along the length of the assembly 1. This solution offers the greatest resistance to mechanical stresses, while being made with inflatable objects having the same diameter, and therefore being more easily mass-produced.

[0041] Figure 5b illustrates a second embodiment in which the first tubular segments 20 and the mast 8 all have circular cross-sections of the same diameter and are held together by a peripheral strap 30, or several peripheral straps 30 that 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 up to 0.8 bar (8 x 10 4 Pa), whereas a single tubular captive air bladder with a circular cross-section and a diameter of 450 mm could only withstand a maximum pressure of 0.25 to 0.3 bar (2.5 to 3 x 10 4 Pa).

[0042] Figure 5c illustrates a variant in which the first tubular segments 20 and the mast 8 all have circular cross-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 by means of first fastening devices 32 and to the mast 8 by means of second fastening devices 34 at their points of tangency. The assembly 1 thus obtained includes at least one peripheral fastening strap 30. By way of example, for a variant in which the mast 8 has 12 adjacent first tubular segments in 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 diameter The circumference of assembly 1 is approximately 467 mm. In this variant, mast 8 can be inflated up to 0.45 bar (4.5 x 10 4Pa), the inflation pressure of each of the captive air chambers of the first 20 tubular segments can reach up to 1.3 bar (13 x 10 4 Pa).

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

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

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

[0046] Figure 5g illustrates a variant in which the mast 8 and the first tubular segments 20 have circular cross-sections, the diameter of the mast 8 being smaller than the diameter of the first three tubular segments 20 surrounding it. The resulting assembly also includes at least one peripheral fastening strap 30.

[0047] Other variations and embodiments of the invention can be envisaged within the scope of the invention as claimed. Thus, "n" first inflatable tubular segments can be arranged around the inflatable vertical mast and at all height levels of the vertical mast, or even along 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 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), 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 first adjacent 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 canvas (16) fixed to the second tubular segments (22) of said elongated elements (18).

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