GB1564113A

GB1564113A - Building structures

Info

Publication number: GB1564113A
Application number: GB1283879A
Authority: GB
Original assignee: Devatron Ltd
Current assignee: Devatron Ltd
Priority date: 1976-08-04
Filing date: 1976-08-04
Publication date: 1980-04-02

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.

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.

Attention is drawn to application no, 12837/79, (Serial No; 1564112), which claims means for making a modular frame-work and as described hereinafter.

According to this invention there is provided a connecting member for a modular framework comprising elongate members and connecting members, the connecting members having means for engaging one elongate members intermediate its ends and means for receiving an end of one of the other elongate members at an acute angle determined by the receiving means, to, and with its axis extending across on one side of, said one elongate member, said receiving means being arranged for blocking longitudinal movement of said other elongate member in at least one direction.

A dome shaped structure may include a modular framework made from elongate members and said connecting members and which when viewed normal to the surface of the structure defines a major substantially equilateral triangle, at least a portion of each side of the major triangle being associated with, by forming at least portions of, two sides of respective substantially identical minor substantially equilateral triangles, the sides of the maJor triangle being associated respectively with the sides of different pairs of minor triangles.

The structure may have a plurality of such major triangles arranged in rows extending between marginal portions of the structure, each of the minor triangles between the rows having its sides associated respectively with sides of different major triangles.

A dome-shaped structure may instead include a modular framework made from elongate members and said connecting members and which, when viewed normal to the surface of the structure, defines a hexagon, at least a portion of each side of the hexagon being associated with, by forming at least a portion of, one side of a triangle, the sides of the hexagon being associated with different respective triangles.

The structure may have a plurality of such hexagons regularly distributed.

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 example only, with reference to the accompanying drawings wherein: Figure I 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; 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 indentical 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 forms 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 Sa 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). Clearly the -linear and other central groups of hexagons, the curvature of the structure must be arranged to be less in the direction of elongation in a graded fashion relative to that in the direction in which the curvature is a maximum.

Simple formulae determine the number of rods needed for a particular dome construction. For example, consider a partspherical dome (i.e. a single central hexagon in the basic sub-assemblv 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 Running total No. of rods 1 12 12 2 30 42 3 48 90 4 66 156 n n 12 + (n - 1)18 E 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 + {}88 (x +(x - 1)8 2 12 + (x - 1)8 + 3 12 + (x - 1)8 + 2(18 +(x - 1)12) 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: n Z (6n - 2) (2x + 1) 1 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 (Registered 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 one 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 bv moving the sleeves 4 along the rods they engage. Means may be provided for adjustablv 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 at least a portion of each of the sides of the major triangles forms at least portions of two sides of respective minor triangles 301.

When covering panels are provided 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.

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 watershed arrangement can be achieved.

Alternatively. other means can be provided to act as a watershed and draught excluder, the 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. Also the overlapping of the covering panels to form a watershed is more simply done on the inside 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.

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 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 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, glassfiber, reinforced epoxv resin, ferro-cemento. steel aluminium. etc.

WHAT WE CLAIM IS: 1. A connecting member for a modular framework comprising elongate members and connecting members, the connecting member having means for engaging one elongate member intermediate its ends and means for receiving an end of one of the other elongate members at an acute angle determined by the receiving means, to. and with its axis extending across on one side of. said one elongate member, said receiving means being

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 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 at least a portion of each of the sides of the major triangles forms at least portions of two sides of respective minor triangles 301. When covering panels are provided 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. 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 watershed arrangement can be achieved. Alternatively. other means can be provided to act as a watershed and draught excluder, the 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. Also the overlapping of the covering panels to form a watershed is more simply done on the inside 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. 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 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 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, glassfiber, reinforced epoxv resin, ferro-cemento. steel aluminium. etc. WHAT WE CLAIM IS:

1. A connecting member for a modular framework comprising elongate members and connecting members, the connecting member having means for engaging one elongate member intermediate its ends and means for receiving an end of one of the other elongate members at an acute angle determined by the receiving means, to. and with its axis extending across on one side of. said one elongate member, said receiving means being

arranged for blocking longitudinal movement of said other elongate member in at least one direction.

2. A connecting member according to Claim 1 wherein said receiving means comprises a cup. A

3. A connecting member according to Claim 2 wherein said cup has means for blocking withdrawal of said other elongate member from the cup.

4. A connecting member according to any one of the preceding Claims wherein said engaging means comprises a sleeve of a resiliently flexible material and said receiving means includes means for gripping said one other elongate member so that the latter extends generally tangentially to said sleeve.

5. A connecting member according to Claim 4 as appendent to Claim 2 wherein said cup is secured via a spacer to the sleeve.

6. A connecting member for a modular framework comprising elongate members and connecting members, said connecting member being substantially as described herein with reference to Figure 4 or Figures 3 and 4 of the accompanying drawing.

7. A dome-shaped structure including a modular framework made from elongate members and connecting members each according to any one of the preceding Claims and which framework when viewed normal to the surface of the structure defines a major substantially equilateral triangle at least a portion of each side of the major triangle being associated with, by forming at least portions of, two sides of respective substantially identical minor substantially equilateral triangles, the sides of the major triangle being associated respectively with the sides of different pairs of minor triangles.

8. A structure according to Claim 7 wherein a plurality of such 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 sides of different major triangles.

9. A dome-shaped structure including a modular framework made from elongate members and connecting members each according to any one of Claims 1 to 6 and which framework, when viewed normal to the surface of the structure, defines a hexagon, at least a portion of each side of the hexagon being associated with, by forming at least a portion of one side of a triangle, the sides of the hexagon being associated with different respective triangles.

10. A structure according to Claim 9 wherein there is provided a plurality of regularly distributed hexagons with a single hexagon being central to consecutively formed rings of hexagons to form a part-spherical shaped dome.

11. A structure according to Claim 9 wherein consecutive rings of hexagons are formed round a central linear arrangement of at least two hexagons to form an elongate, part-ellipsoidal shaped dome.

12. A structure according to Claim 9 wherein consecutive rings of hexagons are formed round a central group of at least three hexagons.

13. A structure according to any one of Claims 7 to 12 wherein said elongate members are substantially identical and said connecting members are substantially identical.

14. A structure according to any one of Claims 7 to 12 wherein each said elongate member is of uniform cross-section.

15. A dome-shaped structure substantially as described herein with reference to Figure 1 or Figure 2 or Figures Sa 5b or Figure Sc or Figure 6 of the accompanying drawings.