GB1564111A - Building structures - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO BUILDING STRUCTURES (71) We, DEVATRON LIMITED, a British Company of Westhall, Insch, Aberdeenshire, Scotland. do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to means for making structures for use as buildings.

There have been several attempts to devise strong, light modular building structures which are simple and economical to construct. Many of these attempts have centred on the geodesic type of construction and have the disadvantage that such structures have required a plurality of differently sized building elements and become complicated to construct.

Also, the development of such modular building structures has been hampered by the somewhat restricted range of covering available for modular frameworks. Of particular interest is the application for modular structures in horticulture where the most commonly used covering comprises glass panels. Glass panels are notoriously fragile, are becoming increasingly expensive to produce and instal and suffer from several drawbacks with regard to obtaining and maintaining desired temperature levels within any given structure.

According to a first aspect of this invention there is provided a double-walled covering panel suitable for use with a framework of interconnected structural members, said panel comprising a double layer of a plastics material sealingly connected at a marginal portion so as to enclose an internal space of the panel between the layers of the double layer, at least one of the layers being light transmissive as defined hereinbelow, at least a portion of one of the layers being flexibly movable relative to the other of the layers to form an inflatable portion of the panel, inflating means providing fluid communication between said internal space and the exterior of the panel for enabling inflation of the inflatable portion by means of a supply of passivised fluid to the internal space via said inflating means, said inflatable portion having means constraining said layers so as to determine spacing between the layers of the inflatable portion, when inflated, by restricting said flexible relative movement of the layers, and means being provided on the exterior of the panel for securing the panel to the framework.

As used herein the expression "light transmissive" means that the layer transmits a substantial proportion of the total light striking the layer even when, as is further explained below, certain portions of the light are selectively filtered out by the material.

According to a second aspect of this invention there is provided a method of manufacturing a covering panel according to said first aspect, said method including the steps of securing constraining means to respective surfaces of two layers of a plastics material at least one of which layers is light transmissive, arranging the layers such that at least a portion of one of the layers is flexible movable relative to the other of the layers, sealingly connecting marginal portions of the layers so as to form a double layer enclosing an internal space of the panel that is bounded by said layer surfaces, providing inflating means enabling fluid communication between said internal space and the exterior of the panel so as to form a portion of the panel that can be inflated by means of pressurised fluid supplied to the internal space via said inflating means, and providing means on the exterior of the panel for securing the panel to the framework.

Preferably said constraining means is secured to said layers by means of dielectric welding.

It is to be noted that the term "dielectric welding" as referred to herein in relation to a workpiece means applying pressure to the workpiece between two electrodes between which a radio frequency electric field is generated.

According to a third aspect of this invention there is provided a housing structure comprising a framework of interconnected members and a covering for the framework that extends across spaces between said interconnected members, said covering comprising a plurality of covering panels according to said first aspect.

Preferably said acute angle is 60 and the receiving means are arranged to hold said other elongate members inclined to an apex through the plane of the smaller angle of which said one elongate member extends so that said other elongate members effectively form a segmented curve round said one elongate member.

The term "segmented curve" as used herein shall be understood to include any graphical, substantially continuous (between its ends), line shape comprising a plurality of straight lines.

In a particularly advantageous form of such a structure the framework includes a plurality of substantially identical elongate members, a plurality of identical connecting arrangements and receiving means of each of said connecting arrangements, each of said connecting arrangements being mounted on an associated one of the elongate members and having its receiving means arranged to receive the ends of two others of the elongate members whose longitudinal axes extend in directions across, on the same side of, said one elongate member, and also being arranged to hold the end of each of said other elongate members so that the latter forms a predetermined acute angle with said one elongate member in plan view.

In our copending Applications Nos (Serial No. 1564112) 12837/79 and 12838/79 (Serial No. 1564113) are described and claimed aspects of certain advantageous forms of such structures and the frameworks thereof.

A preferred form of the structure consists of an elongate, or part-ellipsoidal shaped, dome in which consecutive rings of the hexagons are formed around a central linear arrangement comprising at least two hexagons. A part-spherical dome results when a single hexagon is central to consecutively formed rings.

Embodiments of this invention will now be described by way of examples only, with reference to the accompanying drawings wherein: - Figure 1 is a schematic diagram of a basic framework sub-assembly for a structure embodying this invention; Figure 2 is a schematic diagram of a portion of modular framework built up from the sub-assembly shown in Figure 1; Figure 3 is a perspective view of a part of the framework shown in Figures 1 and 2; Figure 4 is a diagram, partly in section. of a preferred form of connecting member which can be used in the modular framework shown in Figure 3; Figures 5a and 5b are schematic diagrams of a portion of a barrel-shaped dome framework, the rear portion of the framework being omitted from Figure 5a for clarity; Figure 5c is a schematic diagram of a portion of a "triangular-dome" framework;; Figure 6 is a schematic diagram of part of the modular framework of a structure forming another embodiment of this invention; Figures 7 and 8 are schematic plan views of covering panels for the framework shown in Figure 2; Figure 9 is a diagram of a web member used in constructing the covering panel shown in Figure 8; Figure 10 is a plan view of a rectangular covering panel that can be used to replace glass panels in existing structure; Figures 11 and 12 are sectional views taken respectively on the lines 11-11 and 12-12 in Figure 10; Figures 13 to 19 are diagrams illustrating various aspects of the manufacture and construction of the rectangular covering panel shown in Figure 10; and Figure 20 is a sectional view (similar to Figure 11) of a modified form of the panel shown in Figure 10.

It is to be noted that the relative dimensions of, and angles and clearances between, the various structural members illustrated have been exaggerated where necessary for the sake of clarity.

Referring to Figures 1 to 6 of the drawings, a plurality of identical elongate members in the form of tubular rods 1 are interconnected by means of connecting members 2 as shown.

Each rod 1 has its ends received and held in connecting members 2 engaging other rods at their mid-lengths. Two rods partially cross each rod at its mid-length from substantially opposite directions. Thus each rod carries two of the connecting members at its mid-length as well as having its ends held in respective connecting members. The connecting members can be adjusted around the mid-length of the rod to determine the angles of inclination of the partially crossing rods.

It is to be understood that the end of the rod received by its associated connecting member may be spaced longitudinally from or may partially cross (as in Figure 3) or may cross completely the rod carrying the connecting member. However, the two rods must always form an acute angle between their longitudinal axes and this acute angle is preferably 60 . Also, the ratio of the effective rod length to the spacing between the longitudinal axes has been found to provide an indication of the capabilities of the structures which can be built. The effective rod length is the distance between the centres of rise.A "centre of rise" is the intersection of the rod's longitudinal axis with the line of extended radius of rod (1) which passes through the apex formed by crossing rods (1' in Figure 3) (where the crossing rods overlap the effective rod length is less than the actual rod length). The preferred ratios lie in the range 33.1 to 40.1.

In Figure 1 is shown the basic part-spherical dome. It will be seen that the rods 1 define a central hexagon 10 each of whose sides subtends a triangle 11. To this basic sub-assembly further rods and connecting members are added to form a ring of hexagons 10' around the central hexagon 10 as shown in Figure 2. This process of building consecutive concentric rings of hexagons can be repeated until the desired size of modular framework is built. In Figure 2 the circles 3' indicate where connecting members 2 are provided between the rods.

It will be seen from Figure 2 that the modular dome framework has regularly spaced hexagons 10 and each side of each hexagon froms a side of a triangle 11 whose other sides are formed by sides of two other hexagons respectively.

It will be noted that for every hexagon in the framework there are two triangles.

In an alternative form of dome (partly shown in Figures 5a and 5b), the central basic arrangement is a line of hexagons 100 around which consecutive rings of hexagons 100' are formed. The direction of the line of hexagons 100 determines an elongation of the dome framework resulting in a barrel-shaped dome. It is to be noted that as well as an elongation along one axis it is possible to employ a central arrangement of more than two hexagons (e.g., as in Figure Sc three hexagons 200 having their centres.forming the respective apices of a notional triangle and surrounded by rings of hexagons 200' - in this case the dome has a shape in plan view which is generally triangular).

Simple formulae determine the number of rods needed for a particular dome construction. For example, consider a part-spherical dome (i.e. a single central hexagon in the basic sub-assembly as shown in Figure 1). The basic sub-assembly has twelve rods and each consecutive ring of hexagons requires eighteen more rods than the preceding ring.

Thus for a part-spherical dome: Ring No. of rods per ring Rmnning total No. of rods 1 12 12 2 30 42 3 48 90 4 66 156 n n 12 + (n - 1)18 z 12 + (n -1)18 More generally for a dome having a basic linear sub-assembly of x hexagons: Ring No. of rods per ring 1 12 + (x - 1)8 2 12 + (x - 1)8 + (18 + (x - 1)12) 3 12 + (x - 1)8 + 2(18 + (x - 1)12 l n 12 + (x - 1)8 + n(18 + (x - 1)12) which simplifies to (6n - 2) (2x + 1) Thus the total number of rods needed for a dome construction having a basic linear sub-assembly of x hexagons is:

where n is the number of hexagon rings taking n = 1 to be the basic sub-assembly.

As can be seen from Figure 4., each connecting member 2 comprises a cylindrical sleeve 4 of a resilient material such as Delrin (Trade Mark) or nylon or PVC or rubber or high density polyethylene. A cup 5 of a relatively rigid plastics material is connected to the sleeve 4 via a frusto-conical spacer 6 (preferably made of a resiliently flexible material such as PVC) by means of a screw-threaded bolt 7 engaging a retaining nut 8 of the cup 5. A screw-threaded bolt 9, diametrically opposite the bolt 7 engages a retaining nut 12 and engages a shoulder 13 of an end-cap 14 secured by adhesive on the end of the rod 1'. Thus while the bolt 7 can be tightened to a required degree before a rod 1 is inserted into the sleeve 4, the withdrawal of the bolt 9 enables the capped end of the rod 1' to be inserted into the cup 5 to be trapped there when the bolt 9 is tightened.

The end-cap 14 has a groove 15 (shown in broken line in Figure 4) which enables the portion of the bolt 7 projecting into the cup 5 to pass relative to the end cap during insertion of the rod 1 into the cup 5. The rod can then be partially rotated before tightening of the bolt 9 to move the groove 15 out of alignment with the bolt 7 (as in a bayonet connection).

The resilience of the sleeve 4 enables a small amount of movement of the cup 5 relative to the sleeve 4 and enables the rods to take up the forces in a dome-shaped structure (part of which is shown in Figure 2) in an acceptable manner.

It is to be noted that the ends of the two rods partially crossing over the third rod are almost aligned so that the rods form a substantially straight line in plan view. (Figures 1 and 2). The cup 5 is provided with vent 16 to allow release of air trapped by insertion of the rod 1'.

If desired the ends of the rods whose axes extend on one side of their associated transverse rod can intercept the transverse rod at positions spaced symmetrically on either side of the mid-length of the transverse rod instead of at mid-length as illustrated. It is clear that there are two alternative ways in which this divergence from the illustrated embodiment can take place. In one way, the hexagons 10 get larger and the triangles 11 smaller and in the other way the hexagons get smaller and the triangles larger. The intercepts may be movable from mid-length by moving the sleeves 4 along the rods they engage. Means may be provided for adjustably securing the sleeves 4 on their associated rods or the sleeves 4 may be sufficiently snugly fitting for friction to provide the necessary anchorage.In an alternative embodiment (not shown) the receiving means (such as the cups 5) may be secured to a single sleeve (4) fixedly positioned at the mid-length of its associated rod.

The connecting members 2 also have depending screw-threaded spigots 18 having nuts 19 for engaging and retaining a covering for the structure. Alternatively flexible nylon ties or cords may be used instead of the spigots 18 and nuts 19.

As is indicated in Figure 3, the two rods partially crossing over the third, transverse rod are inclined so that a generally segmented curved outline round the third, transverse rod is obtained with an extensive structure of the type shown in Figure 2.

Preferably the rods and connecting members are provided in sufficient numbers to form a modular framework for a generally spherical dome constituting a portion of the sphere slightly less than hemispherical. The volume within the dome will then depend on the length of rod supplied.

The fact that the dome is less than hemispherical means that the peripheral or marginal rings of hexagons are not lying normal to the ground or other base foundation for the structure, but are sloping inwardly towards the top of the dome. It has been found that this distributes the structural loads in a satisfactory manner.

In an alternative form of structure to the hexagonal-triangular framework described above. the hexagons can be replaced by substantially equilateral major triangles each of whose sides is associated with two substantially equilateral minor triangles, as shown in Figure 6. This can be done by arranging that the two rods crossing the third, transverse rod form an acute angle between them on one side of the transverse rod instead of extending in substantially opposite directions. The major triangles 300 extend in rows between the margins of the dome. As with the hexagonal-triangular arrangement the connections between crossing rods may be at the mid-length of the rod carrying the connecting members or may be at symmetrical positions on either side of mid-length. Thus as least a portion of each of the sides of the major triangles forms at least portions of two sides of respective minor triangles 301.

Referring to Figures 7 to 9.. a preferred form of covering for the modular framework comprises hexagonal and triangular inflatable covering double-walled panels 101, 102 respectively, made for example of a transparent plastics material. As in the rectangular covering panel described below each double-walled panel 101, 102 comprises a substantially air-tight double layer of reinforced laminated vinyl material, the panel layers being welded together and reinforced by PVC (polyvinyl chloride) edge stiffeners at their margins. The welded marginal portions are provided with apertures for engaging the spigots 18 of the connecting members.

The transparent vinyl material of the panel layers may comprise a double layer of PVC reinforced by means of a 100 denier nylon fibre mesh laminated between the layers of PVC.

Each of said PVC layer may be 13.335x10-2 m.m. thick. Alternatively the vinyl material may be polyvinylfluoride (PVF) each layer being between 7.62x 10.2 m.m. and 10.16x10 m.m. thick.

Between the panel layers are provided constraining means in the form of transverse layer-spacing webs or reeds 103 coated with a reflective metallic material so that light striking the panel at a wide range of angles of incidence is transmitted through the transparent layers is and optionally reflected into the dome instead of tending to pass along a chord of the dome and re-emerging through other panels as could occur with low angles of incidence. The webs can fold flat, similarly to venetian blinds, when the panels are deflated.

The basic material from which the webs are made is PVC or other suitable vinyl material and where the metallic coating is provided the vinyl material is conveniently laminated with a polyester material carrying the metallic coating.

As can be seen from Figure 7 in the hexagonal panel, the webs 103 are elongate. The webs have their longitudinal edges secured to the respective layers. By arranging the webs in three groups of parallel webs as shown, all the webs can be made of the same length, greatly facilitating assembly of the panel.

Referring particularly to Figures 8 and 9., the triangular panel is provided with a unified web member 104 formed for example from the same type of laminated material as the panel layers.

The web member 104 comprises four discs 105, 106, 107 and 108 interconnected in chain fashion by webs 109. Discs 105, 107 are superimposed and secured (as by dielectric welding) to the inner surface (to be) of one of the layers of the double layer. Discs 106, 108 are then superimposed and secured to the inner surface (to be) of the other layer of the double layer.

The result is (as indicated in Figure 8) that the discs form parts of the panel layers and the webs 109 extend longitudinally between the panel layers. By marking the discs with stars 110 (as shown), the superposition of the discs, in such a way as to prevent the webs 109 becoming twisted, is facilitated. The star of one disc 105. 106 is then aligned with the star of its associated disc 107, 108 respectively before being secured to the appropriate layer of the double layer.

In a preferred form the transparent panels have their vinyl layers tinted to selectively exclude certain types of light radiation radiation, e.g.. denaturing radiation and radiation that inhibits germination, so that the covered dome can be used as an intensive cultivation housing.

Referring to Figures 10 to 20., there are illustrated the constructional and manufacturing aspects of a rectangular covering panel that can be used to replace glass panels in existing buildings and other structures.

The rectangular covering panel 20 (Figure 10) comprises a double layer of flexible plastics material (such as one of the vinyl materials mentioned above). The double layer comprises a top layer 21 and a box layer 22 (so called because the layer is formed by gathering the corners of a rectangular sheet to provide an open-topped box shape). Along two parallel edges of the panel stiffening members 23 are provided while edge fastening means in the form of zips 24 (such as those sold under the Trade Mark FLEXIGRIP) are secured to the other two parallel edges.Inflating means in the form of two inflation valves 25, 26 (of which at least one is a non-return valve) are secured to the top layer and provide fluid communication through the top layer into an inflatable central portion 27 of the panel for enabling inflation of said portion 27 by means of a supply of pressurised fluid therethrough.

Webs or reeds 28 similar to the webs 103 in Figure 7 are secured between the layers 21, 22 and extend parallel to each other between the zips 24.

As can be seen from Figure 11., the inflated panel is generally flat in that the webs 28 function as constraining means to restrain the layers from freely adopting their natural convexity due to inflation forces. It will however be appreciated that where the constraining means act directly on only selected parts of the panel layers a limited degree of convexity will still appear between those parts thereby imparting a corrugated appearance to the panel.

The general flattening of the central portion by the webs enables the panel to be used in relatively conventional structures in situations employing substantially planar panels as well as providing strength. The zips 24 enable the panels to be secured to each other and to framework members where the latter are also provided with zips, During manufacture. the vinyl material is taken from a roll and cut into portions of the correct size which are marked for subsequent operations using a silk-screen process.

Where "welding' is referred to below it is to be understood that dielectric welding is used.

One of the zips 24 is then welded to one marginal edge portion of the top layer leaving a free portion of the top layer at each end of the zip.

The stiffening members 23 are then each tack-welded to the top layer along a line spaced from the edge of the top layer leaving a free edge portion 29 (Figure 13). Electrodes E of the dielectric welding machine are shown for completeness. The margin of the top layer is then folded over, tightly about the stiffening member and the edge portion 29 is welded to the top layer to form a pocket 30 containing the sitffening member.

The other zip 24 is then welded to that edge portion of the box layer to be welded to the, as yet, free edge portion of the top layer. It is to be noted that although reference has been made to the zips 24 being welded to the 'edge portions" of the top and box layers, in fact the zips are spaced from the edges to leave free edge portions 31, 32 of the top and box layers respectively. (See Figure 15).

The webs (or reeds) 28 (Figure 16) are then welded to the box layer. As can be seen from Figure 16 the webs are provided with eyelets 33 to provide fluid communication through the webs. Also the eyelets are arranged so as to present least resistance to flow at the centre of the web. The purpose behind providing the eyelets 33 is that a flow of gas under pressure (such as CO2) can be maintained through the panel (using the valves 25, 26) to inhibit undesirable convection currents. The use of carbon dioxide as the inflating gas (instead of air) provides significant advantages in thermal insulation.

After the webs have been welded to the box layer, the webs are welded to the top layer and the top and box layers are welded together round their edge portions 31, 32. It will be understood that until this point the box layer has been in the form of a flat sheet since its corners need only be gathered immediately prior to welding to the top layer. Figure 19 illustrates the way in which the corners are gathered by folding upwardly from the plane of the drawing on the line 34 and downwardly on the lines 35 which are at an angle 0 of, approximately, 11" from the perpendicular to the edge of the box layer. The choice of angle 6 determines the size of a corner flap which projects upwardly and can be folded over to secure the gather.

As an alternative to the separate operations for welding the reflective webs to the top and box layers, a single operation can be carried out (Figures 17 and 18) using webs creased and folded along their longitudinal axes. The webs are each provided on one side with metallised coating 36 to provide reflection and folded with the coating 36 innermost. The coatings 36 resist being welded together during dielectric welding due to their metallic nature. Both top and box layers can then be simultaneously welded to the PVC of the web (as illustrated in Figure 17) without welding together of the coatings 36. In addition, all the webs can be welded in a single operation using a multi-electrode tool, each electrode welding a respective one of the webs.Where the webs are not provided with metallic coatings, a removable metal foil strip may be provided between the surfaces of the folded web to prevent the web being welded into a permanently folded state.

The welding together of the top and box layers can be done as a plurality of edge welding operations or can be done in a single operation using a rectangular electrode into which the box layer is fitted with its edge portions overlapping the electrode. The edge portions of the top layer are then applied under pressure to the edge portions of the box layer while welding is carried out in a single operation.

It should be noted that the spacing of the zips inwardly of the layer-to-layer welds ensures that the inflation of the central portion causes the zip to take up a corrugated outline following the corrugations of the top layer. This reduces any tendency for the zips to splay the ends of the panel which would cause varying and unreliable end dimensions of the panel.

Also, in the triangular panel shown in Figure 8 elongate web members such as 28 may be provided instead of, or in addition to. the unified web member.

Referring now to Figure 12. there is shown in broken line a modified form of covering panel for use in heating water. An auxiliary, thermally absorptive layer 37 (preferably of a fungus-resistant material) is welded to the top layer 21 and has two inflation valves 38 (one of which is a non-return valve) secured to it at diagonallv opposite corners of the panel.

By passing water through the heating space between the layers 21 and 37, solar radiation received via the box layer and reflective webs 28 can be used to heat the water. If carbon dioxide is passed through the panel between the top and box layers and subsequently bubbled through water further extraction of heat energy can be obtained. Thus the modified covering panel can be used as a solar heating panel.

In an alternative form of covering panel one of the panel layers may be made of a reflective material.

The covering panels may take other forms and can for example have one or both sides of the central inflatable portion formed by semi-rigid material. The semi-rigid material of one of the layers may extend to the margins of the panel so as to form a substantially flat surface. The marginal portions of one or both layers are formed by a flexible plastics material welded to the semi-rigid material. Where dielectric welding is used to attach the webs to the layers of plastics material, at least one of the layers is preferably flexible for ease of construction.

Referring to Figure 20, there is shown an example of a covering panel 40 having its top and box layers 41, 42 formed of a semi-rigid material (such as a 1.1 m.m. thick sheet of the reinforced, laminated PVC mentioned earlier). The marginal portions 43 of the layer 42 are formed of flexible material such as the reinforced laminated PVC used for the panels shown in Figures 7 to 9. Webs 44 are provided between the layers 41, 42 as in the panel shown in Figure 11 except that each web is secured to the layers 41, 42 as separate halves (divided longitudinally of the web) and the halves are welded together as at 45 when they have all been secured to their respective layers 41, 42. It will be seen from Figure 20 that the corrugations evident from Figure 11 are not present due to the additional degree of rigidity of the material used for the layers 41, 42.The lack of corrugation enhances optical accessibility through the panel where the latter is to act as a viewing window. Otherwise, the panel 40 is similar in construction to the panel 20.

It is to be noted that in all the forms of inflatable panel, the inflation serves to inhibit fatigue of flexible surfacing materials used.

When the covering panels are employed on a modular framework (as shown in Figures 1 to 6) the nuts 19 are used to retain the covering panels in place on the spigots 18. The spigot-engaging means take the form of reinforced-edge apertures 111 in the welded marginal portions of the covering panels. The welded marginal portions may be provided with fastening means other than the zips 24 for sealingly interconnecting the covering panels. A suitable type of fastening means is the hook-and-loop type of fastening strip (as sold under the Trade Mark VELCRO).

It is to be understood that while the spigots 18 depend from the connecting members in the example described above, the spigots could be arranged to project upwardly between the cups 5. By suitable overlapping of the marginal portions of the covering panels a water resisting arrangement can be achieved.

Alternatively, other means can be employed to provide a water resisting and draught excluding connection, the inflatable covering panels mainly providing thermal insulation between the interior and exterior of the dome. In this case the framework is outside the surface provided by the covering panels and so, while providing support for the construction, does not intrude into the interior, nor take up heat and light there, nor gather dirt from the interior.Also the overlapping of the covering panels to form a water resisting enclosure is more simply done with the panels on the inside of the supporting framework since the outermost panels are at the centre of the dome and are put on first whereas if the panels were mounted on to the outside of the framework the outermost central panels can only be put on after all the other panels have been put on if the desired water-resisting arrangement is to be most readily achieved.

It is to be understood that the periphery of the dome framework can be provided with a conventional ground foundation or be provided with a modular cylindrical foundation for ease of disassembly.

It is intended that the form of modular framework described above will provide a structure having the following characteristics:- 1. It is a structure with a low weight and low bulk able to be easily transported with modest means (disassembled).

2. It is an efficient structure, modular, every strut is identical to every other strut, which allows it to be produced en masse.

3. It is to be a dome with the low surface to volume ratio of the spherical (or nearly spherical) form and the advantage of a large clear span achieved with members of modest dimension.

4. It is able to be erected in a matter of hours providing shelter which can be disassembled again and moved. No special tools are required.

5. It is as universal a design as possible to allow diverse local materials to be adapted to the design of the elongate members of the framework, e.g., wood, bamboo, glass fibre reinforced epoxy resin, ferro-cemento. steel, aluminium, etc.

WHAT WE CLAIM IS: 1. A double-walled covering panel suitable for use with a framework of interconnected structural members, said panel comprising a double layer of plastics material sealingly connected at a marginal portion so as to enclose an internal space of the panel between the layers of the double layer. at least one of the layers being light transmissive as defined herein before, at least a portion of one of the layers being flexibily movable relative to the other of the layers to form an inflatable portion of the panel. inflating means providing fluid communication between said internal space and the exterior of the panel for enabling inflation of the inflatable portion by means of a supply of pressurised fluid to the internal

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (54)

**WARNING** start of CLMS field may overlap end of DESC **. surface. The marginal portions of one or both layers are formed by a flexible plastics material welded to the semi-rigid material. Where dielectric welding is used to attach the webs to the layers of plastics material, at least one of the layers is preferably flexible for ease of construction. Referring to Figure 20, there is shown an example of a covering panel 40 having its top and box layers 41, 42 formed of a semi-rigid material (such as a 1.1 m.m. thick sheet of the reinforced, laminated PVC mentioned earlier). The marginal portions 43 of the layer 42 are formed of flexible material such as the reinforced laminated PVC used for the panels shown in Figures 7 to 9. Webs 44 are provided between the layers 41, 42 as in the panel shown in Figure 11 except that each web is secured to the layers 41, 42 as separate halves (divided longitudinally of the web) and the halves are welded together as at 45 when they have all been secured to their respective layers 41, 42. It will be seen from Figure 20 that the corrugations evident from Figure 11 are not present due to the additional degree of rigidity of the material used for the layers 41, 42.The lack of corrugation enhances optical accessibility through the panel where the latter is to act as a viewing window. Otherwise, the panel 40 is similar in construction to the panel 20. It is to be noted that in all the forms of inflatable panel, the inflation serves to inhibit fatigue of flexible surfacing materials used. When the covering panels are employed on a modular framework (as shown in Figures 1 to 6) the nuts 19 are used to retain the covering panels in place on the spigots 18. The spigot-engaging means take the form of reinforced-edge apertures 111 in the welded marginal portions of the covering panels. The welded marginal portions may be provided with fastening means other than the zips 24 for sealingly interconnecting the covering panels. A suitable type of fastening means is the hook-and-loop type of fastening strip (as sold under the Trade Mark VELCRO). It is to be understood that while the spigots 18 depend from the connecting members in the example described above, the spigots could be arranged to project upwardly between the cups 5. By suitable overlapping of the marginal portions of the covering panels a water resisting arrangement can be achieved. Alternatively, other means can be employed to provide a water resisting and draught excluding connection, the inflatable covering panels mainly providing thermal insulation between the interior and exterior of the dome. In this case the framework is outside the surface provided by the covering panels and so, while providing support for the construction, does not intrude into the interior, nor take up heat and light there, nor gather dirt from the interior.Also the overlapping of the covering panels to form a water resisting enclosure is more simply done with the panels on the inside of the supporting framework since the outermost panels are at the centre of the dome and are put on first whereas if the panels were mounted on to the outside of the framework the outermost central panels can only be put on after all the other panels have been put on if the desired water-resisting arrangement is to be most readily achieved. It is to be understood that the periphery of the dome framework can be provided with a conventional ground foundation or be provided with a modular cylindrical foundation for ease of disassembly. It is intended that the form of modular framework described above will provide a structure having the following characteristics:- 1. It is a structure with a low weight and low bulk able to be easily transported with modest means (disassembled). 2. It is an efficient structure, modular, every strut is identical to every other strut, which allows it to be produced en masse. 3. It is to be a dome with the low surface to volume ratio of the spherical (or nearly spherical) form and the advantage of a large clear span achieved with members of modest dimension. 4. It is able to be erected in a matter of hours providing shelter which can be disassembled again and moved. No special tools are required. 5. It is as universal a design as possible to allow diverse local materials to be adapted to the design of the elongate members of the framework, e.g., wood, bamboo, glass fibre reinforced epoxy resin, ferro-cemento. steel, aluminium, etc. WHAT WE CLAIM IS:

1. A double-walled covering panel suitable for use with a framework of interconnected structural members, said panel comprising a double layer of plastics material sealingly connected at a marginal portion so as to enclose an internal space of the panel between the layers of the double layer. at least one of the layers being light transmissive as defined herein before, at least a portion of one of the layers being flexibily movable relative to the other of the layers to form an inflatable portion of the panel. inflating means providing fluid communication between said internal space and the exterior of the panel for enabling inflation of the inflatable portion by means of a supply of pressurised fluid to the internal

space via said inflating means, said inflatable portion having means constraining said layers so as to determine spacing between the layers of the inflatable portion, when inflated, by restricting said flexible relative movement of the layers, and means being provided on the exterior of the panel for securing the panel to the framework.

2. A panel according to Claim 1 wherein said constraining means is secured to said layers by means of dielectric welding.

3. A panel according to Claim 1 or Claim 2 wherein the constraining means is secured to surfaces of the layers within said internal space.

4. A panel according to any one of Claims 1 to 3 wherein both of the layers are light-transmissive.

5. A panel according to any one of Claims 1 to 4 wherein the light-transmissive layer or at least one of the light-transmissive layers is transparent.

6. A panel according to any one of Claims 1 to 5 wherein the light-transmissive layer or at least one of the light-transmissive layers is tinted.

7. A panel according to any one of the preceding Claims wherein at least one of said layers is reflective.

8. A panel according to any one of the preceding Claims wherein said constraining means has at least one reflective outer surface.

9. A panel according to Claim 8 wherein said constraining means is provided with a reflective coating to form said at least one reflective outer surface.

10. A panel according to any one of the preceding Claims wherein the constraining means are made of a flexible material.

11. A panel according to any one of the preceding Claims wherein the panel is triangular or hexagonal in shape when viewed normally to the major face of the double layer.

12. A panel according to any one of the preceding Claims wherein said constraining means includes a web member extending between said layers.

13. A panel according to Claim 12 wherein the web member is a unified web member having three straps extending between the layers of the double layer.

14. A panel according to Claim 12 wherein said web member is elongate and has its longitudinal edges secured to the respective layers of the double layer.

15. A panel according to Claim 14 wherein eyelets are provided in said web member to facilitate fluid flow through the web member, the eyelets being arranged to provide least flow resistance near the longitudinal centre of the web member.

16. A panel according to Claim 14 or Claim 15 wherein the panel is hexagonal in shape when viewed normally to the major face of the double layer, three groups of parallel identical web members being provided, the respective groups being arranged parallel with alternate sides of the hexagon.

17. A panel according to any one of Claims 14 to 16 wherein said web member comprises two longitudinal portions secured respectively to the layers of the double layer; the two longitudinal portions being joined along the longitudinal axis of the web member.

18. A panel according to any one of the preceding Claims wherein said inflating means includes two inflation valves spaced so that a flow of fluid can be maintained through the central portion of the panel from one of the inflation valves to the other.

19. A panel according to Claim 18 wherein at least one of the inflation valves is a non-return valve.

20. A panel according to any one of the preceding Claims wherein said double layer has its marginal portions sealingly connected by means of dielectric welding.

21. A panel according to any one of the preceding Claims wherein the securing means include apertures in the marginal portions of the panel layers.

22. A panel according to any one of Claims 1 to 21 wherein the securing means comprise fastening means secured to edge portions of the panel to enable the panel to be secured to at least one other similar panel.

23. A panel according to Claim 22 wherein the fastening means comprise strip fasteners extending along the edge portions and arranged inwardly from the edges relative to the sealed periphery of the double layer so that the strip fasteners are subjected to inflation forces and tend to take up said corrugations.

24. A panel according to any one of Claims 1 to 23 wherein at least one major face of the inflatable portion, is constructed so as to adopt a curved configuration with curved portions when the panel is inflated.

25. A panel according to any one of the preceding Claims wherein stiffening members are provided along edge portions of the panel.

26. A panel according to any one of the preceding Claims and further including an auxiliary layer and associated valves, the auxiliary layer being secured to an associated one of the layers of the double layer to form a heating space between the auxiliary layer and its associated one layer of the double layer, the valves enabling fluid flow through the heating space.

27. A panel according to Claim 26 wherein the auxiliary layer is made of a thermally absorptive material.

28. A panel according to any one of the preceding Claims wherein said inflatable portion includes a semi-rigid portion of at least one of the layers of the double layer.

29. A panel according to any one of the preceding claims wherein the plastics material is a vinyl material.

30. A panel according to Claim 29 wherein the vinyl material is polyvinyl chloride.

31. A panel according to any one of the preceding claims wherein the plastics material is a laminated material.

32. A panel according to Claim 31 wherein the laminated plastics material comprises a reinforcing nylon fibre mesh laminated between layers of polyvinyl chloride.

33. A covering panel for a framework of interconnected structural members, said panel being substantially as described herein with reference to Figure 7 or Figures 8 and 9 or Figure 10 to 19 or as modified by Figure 20 of the accompanying drawings.

34. A method of manufacturing a covering panel according to Claim 1, said method including the steps of securing constraining means to respective surfaces of two layers of a plastics material at least one of which layers is light transmissive, arranging the layers such that at least a portion of one of the layers is flexibily movable relative to the other of the layers, sealingly connecting marginal portions of the layers so as to form a double layer enclosing an internal space of the panel that is bounded by said layer surfaces, providing inflating means enabling fluid communication between said internal space and the exterior of the panel so as to form a portion of the panel that can be inflated by means of pressurised fluid supplied to the internal space via said inflating means, and providing means on the exterior of the panel for securing the panel to the framework.

35. A method according to Claim 34 wherein said constraining means is secured to said layers by means of dielectric welding.

36. A method according to Claim 34 or Claim 35 wherein the marginal portions of said double layer are sealingly connected by means of dielectric welding.

37. A method according to any one of Claims 34 to 36 wherein both the panel layers are light-transmissive.

38. A method of manufacturing a covering panel according to any one of Claims 1 to 33, said method being substantially as described herein with reference to Figures 7 to 20 of the accompanying drawings.

39. A covering panel produced by a method according to any one of Claims 34 to 38.

40. A housing structure comprising a framework of interconnected members and a covering for the framework that extends across spaces between said interconnected members, said covering comprising a plurality of covering panels according to any one of Claims 1 to 33.

41. A housing structure according to Claim 40 wherein said framework includes a plurality of substantially identical elongate members, a plurality of identical connecting arrangements and receiving means of each of said connecting arrangements, each of said connecting arrangements being mounted on an associated one of the elongate members and having its receiving means arranged to receive the ends of two others of the elongate members whose longitudinal axes extend in directions across, on the same side of, said one elongate member, and also being arranged to hold the end of each of said other elongate members so that the latter forms a pre-determined acute angle with said one elongate member in plan view.

42. A housing structure according to Claim 41 wherein each of said connecting arrangements is mounted on its associated elongate member in such a position that the ratio of effective length of each of said other elongate members when held in the receiving means of said connecting arrangement, to the spacing between the longitudinal axis of said one and said other elongate members is in the range 33:1 to 40:1.

43. A housing structure according to Claim 41 or Claim 42 wherein said acute angle is substantially 60".

44. A housing structure according to any one of Claims 41 to 43 wherein the receiving means of the connecting arrangement are arranged to receive elongate members from substantially opposite directions.

45. A housing structure according to any one of Claims 41 to 44 wherein each of said connecting arrangements comprises two connecting members and respective receiving means of the connecting members, the receiving means of each of said connecting members being arranged to receive one of said other elongate members, said connecting members being movable independently of each other along said one elongate member.

46. A housing structure according to any one of Claims 41 to 45 wherein the receiving means of each of said connecting arrangements are arranged to hold said other elongate members inclined to an apex through the plane of the smaller angle of which said one elongate member extends so that said other elongate members effectively form a segmented curve round said one elongate member.

47. A housing structure according to any one of Claims 41 to 46 wherein respective end caps are provided on the ends of each of the elongate members.

48. A housing structure according to any one of Claims 40 to 47 wherein said framework is modular, comprising substantially identical elongate members and connecting members, at least one substantially equilateral major triangle as seen when viewed normal to the surface of the structure and a plurality of substantially equilateral, identical, minor triangles as seen when viewed normal to the surface of the structure, at least a portion of each side of the major triangle being associated with, by forming at least portions of, two sides of respective ones of the minor triangles, the sides of the major triangle being associated respectively with the sides of different pairs of minor triangles.

49. A housing structure according to Claim 48 wherein a plurality of said major triangles is arranged in rows extending between marginal portions of the structure, each of the minor triangles between the rows having its sides associated respectively with the sides of different major triangles.

50. A housing structure according to any one of Claims 40 to 47 wherein said framework is modular and comprises substantially identical elongate members and connecting members, at least one hexagon of the framework as seen when viewed normal to the surface of the structure and a plurality of triangles of the framework as seen when viewed normal to the surface of the structure, at least a portion of each side of the hexagon being associated with, by forming at least a portion of, one side of one of the triangles, the sides of the hexagon being associated with different respective triangles.

51. A housing structure according to Claim 50 and including a plurality of regularly distributed hexagons, one of the hexagons being central and rings of hexagons being provided consecutively around the single central hexagon to form a part-spherical shaped dome.

52. A housing structure according to Claim 50 and including a central linear arrangement of at least two hexagons and consecutive rings of hexagons formed around the central linear arrangement to form an elongate part-ellipsoidal shaped dome.

53. A housing structure according to Claim 50 and including a central group of at least three hexagons and consecutive rings of hexagons formed round the central group.

54. A housing structure substantially as described herein with reference to Figure 1 or Figure 2 or Figures Sa and Sb or Figure Sc or Figure 6 in conjunction with Figure 7 or Figures 8 and 9 or Figures 10 to 19 or Figure 20 of the accompanying drawings.