TECHNICAL FIELD

This invention relates to polygonal construction modules which combine structural and cladding properties. It is concerned with two-dimensional construction panels — as might be used for weather¬ proof roofs or walls — formed by joining a plurality of such modules edge-to-edge. It also relates to fully or partially cladded three-dimensional structures formed from a plurality of such panels. The modules of particular interest are those of hexagonal or octagonal shape, but the panels and structures formed using these modules may also incorporate other modular elements. The invention is also concerned with construction systems using the modules and panels.

The modules, panels and construction systems of this invention may be employed in a wide range of applications, such as: for the construction for temporary or permanent housing, sheds, barns, garages, huts and the like; for the construction of self-supporting greenhouses, patio covers, awnings, shades, temporary weather shields and the like; for internal linings, partitions, display panels and the like; and for use in recreation as toys, construction kits, cubby-houses, play-ground structures and the like.

BACKGROUND TO THE INVENTION

Many construction systems based on frame structures with tetrahedral, hexagonal and/or octagonal modules have been proposed and used. For example, Australian Patent No 475,424 discloses a geodesic space-frame structure of icosahedral shape having pentagonal and hexagonal modules. These modules were themselves formed from isosceles triangles so that the dome-like structure could be cladded with triangular-shaped sheet-material modules. While such geodesic structures (as pioneered by the American inventor Richard Buckmaster Fuller) are essential dome-like, a great variety of strut-and- node space-frames based on tetrahedral, hexahedral, octahedral modules are also known and widely used (see, for example Australian patent 460,682). These are also commonly clad with sheet-material panels of similar modular polygonal shapes, but the cladding panels rarely contribute to the load-bearing capacity of the structure and are not self-supporting.

English architect Arthur Quarmby, and others following his lead, proposed a variety of self-supporting structures formed by the pleating or folding of large sheets of material, typically glass-reinforced plastic. Many examples were offered in his book 'The Plastics Architect" published by Pall Mall Press, London, 1975 and some of his patents. Full structures were formed by unfolding large sheets on-site to form vaults, domes or hutments complete with roofs and walls, the erection process being much like the

expansion of bellows. Such structures were tailored individually for their sites and folded for transport. However, the large sheets of material could not be dismantled into smaller modules or components for transport so that, for all but the smallest buildings, on-site construction of the sheets was essential thereby eliminating the advantage of factory production.

OBJECTIVES OF THE INVENTION

The objective of the invention is to provide a simple modular construction panel which can be assembled into sheets or structures with integral structural strength and yet be suitable for mass production and transport. More generally, it is the object of the invention to provide an improved modular construction panel, and panel-sheets, structures and construction systems based thereon.

OUTLINE OF INVENTION

The present invention is based upon the realisation that combined cladding and structural modules can be constructed by bracing radially pleated and dished polygonal plates on their concave sides, either with a bracing 'spider' or with a second polygonal plate of substantially the same shape and pleated form as the first plate, the two plates being with their concave faces together. In this context, 'pleating' means that ridges and valleys alternate around the polygonal plate and that, therefore, the polygon must have an even number of sides. Particularly suitable polygons for such modules are those of a regular hexagon or octagon, the hexagon being preferred (though the invention is not limited to either shape). A module formed from two pleated plates in the manner indicated will be light-weight, stiff and hollow, but it can be further strengthened by securing the sides together by plastics foam, by the use of internal pillars or webs, or by dimpling the plates (even to the degree that their centres touch).

Such modules (when viewed side-on) will have undulating edges as their adjacent edges will be angled to one another by less than the normal angle for the respective regular polygon. For example, the angle between two adjacent sides of a hexagonal module (when viewed from the edge of the module) will be less than 120° though the angle of the same to sides viewed in projection from the face of the module will be 120°. The first angle is called the 'edge angle' of a module. Provided modules have the same edge angles they can be joined together by their edges to form panels (which extend in essentially two dimensions). The joining of one module to another may be effected in any one of many ways known in the art, but this will usually be achieved by using flanges formed around the periphery of each module for the purpose. When the flanges extend in-line with the plane of the module, one row of modules in a panel may overlap the next like roof-tiling to facilitate weather-proofing. When the flanges are turned at right angles to the plane of the module, they can be readily welded, glued, clipped, riveted, stitched

or bolted together. Joining strips may also be employed. Of course, the method of joining the plates will depend to some degree upon the material of the plates. Since modules formed from two plates are hollow, they can be filled with plastics foam or the like to improve rigidity and insulation properties.

Any suitable stiff sheet material may be used for the plates, examples being plastic, metal, cellulose card or fibre-board. The plates may be profile-cut in any suitable manner, as by laser-cutting, blanking or guillotining and may be pleated by folding, creasing or pressing. It is also envisaged that plastics, cellulose or fibre-board plates could be formed in a hot pressing operation, while metal plates could be stamped-out in one operation. As the modules need not be large (ie, metres across), they can be easily mass-produced and transported in finished form or as stacks of pleated plates (or spiders) ready for assembly.

It should be noted that, in order to form a module which is a regular polygon (in projection) the blank for a plate cannot be a regular polygon. Those pleat-lines which form ridges will be shorter than those which form valleys, the difference in their lengths determining the depth of pleating and the thickness of the module. The ratio of the lengths of a valley to a ridge of a blank (or plate) is an important parameter and is called the 'pleat ratio'. This ratio determines the depth of pleating (or the thickness of the module), and the edge angle and, thus, the degree of dimpling of the surface of a panel. This, in turn therefore, determines the minimum angle at which a panel can be disposed to the horizontal before puddling occurs in the dimples during rain. It also determines the non-zero (or non-180 ⁰ ) 'transition angle' at which one panel will join to another 'naturally' without the need for corner modules (here-after called sub-modules).

For example, a pleating ratio of 1.06 allows a transition angle of 120° (included angle) between two panels formed from hexagonal modules, while a pleating ratio of 1.16 allows a transition angle of 90° for similar panels.

Thus, the principal terms used in this specification are as follows:

'Module' indicates a braced and pleated polygonal plate, the bracing by the use of a spider or

(more preferably) by the use of a second pleated plate.

'Plate' indicates a sheet of material of polygonal shape (usually hexagonal or octagonal) which is radially pleated to form a component of a module, an un-pleated plate being referred to as a

'blank'. A bracing plate need not be continuous as portions of its blank can be cut away to reduce its weight to create (for example) a spider-like lattice of triangles.

'Spider' indicates a star-shaped structure used for bracing a pleated plate to complete a module.

'Panel' indicates a plurality of modules assembled edge to edge to form a generally planar (two- dimensional) array. A panel may, for example, form the wall or roof of a hut (or part thereof).

'Structure' indicates at least two panels assembled at an angle to one another and is, therefore, three dimensional in character. A structure may be, for example, a gabled roof, an arch or a hut.

DESCRIPTION OF EXAMPLES

Having broadly portrayed the nature of the present invention, particular embodiments will now be described by way of example and illustration only. In the following description, reference will be made to the accompanying drawings in which:

Figure 1A illustrates the manner in which a hexagonal module is formed from a pair of plates, while

Figure 1 B shows the formation of a hexagonal module from a plate and a spider. Figure 2A illustrates the manner in which an octagonal module is formed from a pair of plates, while

Figure 2B shows the formation of an octagonal module from a plate and a spider. Figure 3A is an elevation of a vertical panel formed from hexagonal modules, Figure 3B being a sectional elevation taken on plane C-C of Figure 3A, while Figure 3C is a perspective view of the panel of

Figure 3A. Figure 4A is an elevation of a vertical panel formed from octagonal modules, Figure 4B being a sectional elevation taken on plane C-C of Figure 4A, while Figure 4C is a perspective view of the panel of Figure 4A.

Figures 5A is a plan view of a horizontal panel formed from hexagonal modules which overlap one another in the manner of roof tiling, while Figure 5B is a diagrammatic sectional elevation of the panel of Figure 5A taken on section B-B. Figure 6A is a diagrammatic sectional elevation of a panel showing one way of joining the modules, while Figure 6B is a similar view showing another way of joining the modules.

Figures 7A-7C are cross-sections of modules which have been internally strengthened in various ways, while Figure 7D is a plan view of a module strengthened by dimpling, Figure 7E being a section of the module of Figure 7D taken along section E-E of Figure 7D. Figures 8A-8C shown modules which are adapted to generate curved panels, Figure 8A being a plan view of a plate blank modified for the purpose, Figure 8B being a diagrammatic section a module formed from two plates formed from blanks of the type shown in Figure 8A. Figures 9A-9D show the manner in which two panels may be joined along their saw-tooth edges at their characteristic transition angle, each Figure being a perspective view of a panel or panels.

Figure 10A is a diagrammatic perspective of a shed having its walls and roof formed from hexagonal modules, while Figure 10B is an enlarged and simplified semi-exploded view of the gable peak of the shed of Figure 10A.

One way in which a hexagonal module 10 may be formed in accordance with this invention is illustrated by Figure 1A in drawings [a] to [e]. A first plate 11 or blank is cut to a particular hexagonal shape from stiff sheet material (drawing [a]), the shape being a distortion of a regular hexagon (indicated in broken lines) in that each alternate 'radius' (semi-axis or half-diagonal) 12 is lengthened, leaving the other radii (13) unchanged. A substantially identical second plate 14 is formed in the same manner (drawing [b]) but is rotated 30° with respect to plate 11 so that its shorter radii 15 are aligned with the longer radii 12 of plate 11 and its longer radii 16 are aligned with the shorter radii 13 of plate 11. First plate 11 is then pleated (eg, by folding or pressing) so that its lengthened radii (12) form valleys 12a and its normal radii form ridges 13a, forcing the plate into a dish-shape with its convex side uppermost, as indicated by arrow 17 in drawing [c]. The pleated first plate is indicated at 11 a in drawings [c] and [e]. Plate 14 is similarly pleated to form valleys 16a and ridges 15a, forcing it to adopt a concave shape with its convex side lower-most, as indicted in drawing [d] by arrow 18. The pleated second plate is indicated at 14a in drawings [d] and [e]. Note that the designation of which radii is a valley and which is a ridge is determined by viewing each plate from its convex (lower) side, but that however viewed, ridges and valleys alternate around the hexagonal shape. Finally, pleated plates 11 a and 14a are juxtaposed with their concave faces together and the valleys 13a of the first opposite the ridges 15a of the second. When these plates are brought together so that their peripheries are coincident and secured together, they form the module 10 which has undulating edges as shown in drawing [e]. However, in projection, module 10 has the shape of the regular hexagon indicated in broken lines in drawings [a] and [b],

Another way of forming a hexagonal module 10a is shown in drawings [a] to [e] of Figure 1B, upper pleated plate 11a being identical to the first plate of Figure 1A (and being referenced accordingly). Instead of using a second plate to brace the first, this function is performed by a star-shaped spider shown as a flat blank 19 in drawing [b] of Figure 1 B. Spider 19 may be bent to form a dished spider 19a (drawings [d] and [e] and assembled with plate 10a so that the ends of its arms connect to the corners of pleated plate 11a. It will be appreciated, however, that the spider can be formed so that it remains flat rather than dished and so that it has only three arms rather than six. In the latter case, it is desirable to ensure that the arms of the spiders of two adjacent modules do not meet at the same plate corners; that is, to ensure that the spider of one module assists in the bracing of an unbraced corner of a neighbouring module.

Figure 2A illustrates the way in which an octagonal module 20 (drawing [e]) may be formed from a pair of flat blanks 21 and 22 of generally octagonal shape in which every alternate radius has been lengthened (see drawings [a] and [b]). As before, each lengthened radius forms a valley and each normal radius forming a ridge in the corresponding pleated and dished plates 21 a and 22a (see drawings [c] and [d] respectively). Once again, the pleated plates are juxtaposed so that the ridges of one are opposite the valleys of the next (see drawing [e]) and are brought together so that their peripheral edges coincide and are joined together creating module 20. In projection, module 20 forms the regular octagon shown in broken lines in drawings [a] and [b], but on side-view has undulating edges.

Like the hexagon example, an octahedral module 20 can be formed using a spider, as shown in the drawings [a] to [e] of Figure 2B. The first or upper blank 21 and pleated plate 21 a are identical with those of Figure 2A. Instead of the six-legged spider of Figure 1 B, an eight-legged spider 22 is shown as a flat 'blank' in drawing [b]. This blank is bent to form the dished spider 22a which is assembled with plate 21 a to form the bracing of module 20a. As indicated with respect to the hexagonal case, there is no need to dish the spider and half of its legs may be omitted without significant loss of bracing effect.

Turning now to Figures 3A to 3C which illustrate a substantially rectangular panel 30 formed from hexagonal modules 10 (or 10a) described above. It will be seen that one pair of opposing panel edges (32) are of saw-tooth shape and that the other pair of opposing edges (34) are of castellated shape. Because of the undulating character of the edges of each module 10, a grid of depressions or dimples 36 are formed at the junctions between three adjacent modules and a corresponding grid of bumps 38 are formed by the apices of the modules (Figure 3C).

Figures 4A-C show a substantially rectangular panel 40 of octagonal modules 22 and tetrahedronal sub- modules 42, the latter modules being referred to as sub-modules as they are of lesser significance from the standpoint of this invention. It will again be seen that the centres of the octahedral modules 20 form a grid of bumps 44, while the junctions between 20 and 42 form a corresponding grid of dimples or depressions 46.

Figures 5, 6 and 7 show various methods joining hexagonal modules. In Figure 5A and 5B each module 50 is formed with a continuous peripheral flange 52 so that the modules can be arranged in horizontal rows with one edge horizontal, so that the lower edge or flange 52 of each module 50 overlaps the upper edge or flange of the next lower module, as in the case of roof-tiling. The modules may be secured together by rivets, screws or bolts generally indicated at 54. Alternative methods of joining adjacent

modules is indicated by Figures 6A and 6B. In these examples, each module 60 is formed with edge flanges 62 which are bent at right angles to the plane of the module. In the case of Figure 6A, flanges 62 are provided with a return lip so that adjacent modules can be joined together by U-shape clips or strips 64 which can be spot-welded, glued, bolted or simply slid in place. In the case of Figure 6B, the flanges 62 are secured together by screw-fasteners 66.

While the structural rigidity of a module or a panel depends upon the strength and the stiffness of the sheet material from which the plates are formed, as well as upon the manner in which they are joined together, the stiffness of a module can be enhanced in a number of ways. Some of these are illustrated in Figures 7A to 7E. In Figure 7A, a module 70a (shown in section) is strengthened by the use of a central post 71 which extends between the apices of the plates 72 and 73 and is riveted at each end to the respective plate. In Figure 7B, module 70b (also shown in section) is filled with a solid light-weight plastics foam 74 (such as polyurethane), to effect the reinforcement. In Figure 7C, module 70c is fitted with an internal stiffening web 75, but it is also envisaged that a cruciform (or star-shape) web assembly may be used so that the module 70c is stiffened along more than one axis. Finally, as shown in Figures 7D and 7E, a module 70d may be stiffened by pressing a dimple 76 into each plate so as to invert its apex. While it is not essential for the dimples to have facets or for their centres to touch, these features are shown in the drawings and provide excellent stiffening of the module 70d. The centres of dimples 76 may, of course, be secured together by a suitable fastener, further strengthening the module.

It is possible to form cylindrically or spherically curved panels by suitable modification of their component modules. To form a cylindrically curved panel, an asymmetric module may be created by off-setting the pleating centre from the polygon centre. This is illustrated in Figure 8A which shows a hexagonal plate- blank 80 having a pleating centre at 81 but its hexagon centre at 82, the pleating centre being offset on valley pleat-line 83. The second blank-plate (not shown) will have its pleating centre offset by the same amount along the same axis, but on the other side of centre 82; that is, on the ridge pleat 84. Figure 8B shows the resultant module 85 in section and shows the displacement of the pleating centres from the hexagonal centre 82. When a series of modules 85 are assembled into a plate with their 'short' radii aligned and disposed on the same side of their pleating centres, the resulting panel will be cylindrically curved around an axis which is disposed parallel to the radii on which the pleating points lie.

To obtain spherical curvature in a panel, the modules are constructed as illustrated by module 86 in Figure 8C. That is, one plate 87 of each module is cut slightly smaller than the other plate 88 so that, when the module is assembled, it is distorted so that the edges of the two plates are brought into

alignment. The result is a spherically curved module which, when joined to like modules, generates a spherically curved panel.

Panels may be joined at angles to form three-dimensional structures in a variety of ways, the most versatile being to use sub-modules which have the same edge angles as the panel modules and which effect the 'turn'. The number of sub-modules required to effect, say, a 120° junction between two panels of octagonal modules is quite large requiring as many as 20 different blanks to be cut. For panels of hexagonal modules, however, it is possible to effect such an angled joint without any sub-modules. Indeed, as is illustrated in Figures 10A and 10B, it is possible to construct and entire shed (with gabled roof) from panels with hexagonal modules joined with tetrahedronal sub-modules using only five different blanks for the entire construction. It is for these reasons that hexagonal modules are preferred to octagonal modules.

To form three dimensional structures by joining planar panels of hexagonal modules along their edges, use can be made of the natural 'transition angle', T of the panels to be joined (provided they have been formed from modules of the same size and pleating ratio). This is illustrated by Figures 9A-9D. In Figure 9A, the two panels 90 and 91 to be joined at an angle are arranged with their saw-tooth edges toward one another (as if they had just been separated). Panel 91 is then tuned up-side-down (as indicated by arrow 93) and the two panels brought together so that the undulating edges of the modules forming the saw-tooth edge are aligned and in contact. When this occurs, the panels will be at an angle as shown in Figure 9B, the angle being the transition angle T corresponding to the component pleating ratio of the component modules. If, as shown in Figure 9C, panel 90 is turned instead of panel 91 and the two are brought together in the same manner, they will still be arranged at angle T, but the joint will be inverted. as shown in Figure 9D.

Trigonometrical analysis shows that the two practically important transition angles of 90° and 120° correspond to pleat ratios of 1.16 and 1.06 (for hexagonal modules), but that any desired transition angle can be set by suitably adjusting the pleat ratio of the component modules of a panel. Figures 10A and 10B show a shed such as a glass-house 100 formed entirely from hexagonal modules 102 with a pleating ratio of 1.16, but without any 'natural' transitions between panels. The saw-tooth to saw-tooth join between the side wall panel 104 and front wall panel 106, as well as the transition between the roof panel 108 and the front wall panel 106, are effected by the use of tetrahedrons 110 designed to match the edge angles of the modules and to effect the right-angle turns. To align the front wall modules with the roof

angle (the included ridge angle being 120°), a row of tetrahedron modules 112 must also be used. These extend diagonally downwards from the roof-wall junction as shown.

The junction between the side wall and the roof panels involves a castellated edge to a castellated edge and this junction must be effected by both tetrahedrons and right pyramids. Given the geometry of the shed, it will be seen that the wall-to-roof angle is the same as the gable angle (ie, 120°). Therefore, to illustrate the joint more clearly (and to show how the pinnacle join is accomplished, Figure 10B shows the arrangement of modules in an enlarged and simplified manner. In this Figure, the hexagonal modules are shown at 102, the tetrahedral modules are shown at 110 and the triangular or right- pyramidal modules are shown at 124.

It will be appreciated that the examples of the invention described above meet the objects and advantages set out at the beginning of this specification. However, those skilled in the art will also understand that many variations and modifications can be made to the invention as disclosed without departing from the scope of the following claims.