GB2331456A

GB2331456A - Support structure

Info

Publication number: GB2331456A
Application number: GB9825127A
Authority: GB
Inventors: George Andrew Wemyss
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-11-17
Filing date: 1998-11-17
Publication date: 1999-05-26
Anticipated expiration: 2018-11-17
Also published as: GB9724271D0; GB2331456B; GB2331456A9; GB9825127D0

Abstract

A support structure is constituted by a plurality of support units (U) joined together end-to-end. Each support structure (U) is constituted by at least three compression members (11) each having first and second end portions. The first end portions of each pair of adjacent compression members (11) of each support unit are interconnected by a respective tensioned tension member (12), and the second end portions of each pair of adjacent compression members of each support unit are interconnected by a respective tensioned member (12). The first end portion of each compression member (11) of a given support unit (U) is connected to the second end portion of a adjacent compression member of that support unit and to the first end portion of a compression member of the support unit adjacent to the second end portion of said given support unit by a respective further tensioned tension member (14), the further tensioned tension members constituting the means for joining the support units end-to-end.

Description

2331456 SUPPORT STRUCTURE This invention relates to a support structure,

and in particular to an article of furniture such as a chair.

The invention is based on the principle of the tensegrity system, that is to say a structured system in which compression and tension forces are separated out and handled by different members, so that the structure has no inherent size limitations.

According to a first aspect, the present invention provides an article of ftirniture constituted by at least three compression members each having first and second end portions, a plurality of tension members, and a load-bearing support member, the first end portion of each compression member being connected to the second end portion of an adjacent compression member by a respective tensioned tension member, the first end portions of each pair of adjacent compression members being interconnected by a respective tensioned tension member, and the second end portions of each pair of adjacent compressive members being interconnected by a respective tensioned tension member, the load-bearing support member being fixed to the tensioned tension members interconnecting the second end portions of the compression members, In a preferred embodiment, there are four compression members and twelve tension members.

According to a second aspect, the present invention provides a support structure constituted by a plurality of support units joined together endto-end, wherein each support structure is constituted by at least three compression members each having first and second end portions, the first end portions of each pair of adjacent compression members of each support unit being interconnected by a respective tensioned tension member, and the second end portions of each pair of adjacent compression members of each support unit being interconnected by a respective tensioned member, the first end portion of each compression member of a given support unit being connected to the second end portion of an adjacent compression member of that support unit and to the first end portion of a compression member of the support unit adjacent to the second end portion of said given support unit by a respective fin-ther tensioned tension member, the further tensioned tension members constituting the means for joining the support units end-to-end.

In a preferred embodirnent the tensioned tension members interconnecting the second end portions of the compression members of one support unit constitute the tensioned tension members interconnecting the first end portions of the compression members of the adjacent support unit.

Advantageously, the second end portion of each compression member of a given support unit is connected to the first end portion of the adjacent support unit by connection means permitting relative pivotal movement therebetween. Preferably, said adjacent end portions of two connected compression members are formed with aligned apertures, a pin engaging within said aligned apertures constituting said connection means.

In a preferred embodiment the first end portion of a given compression member of each support unit is connected to the second end portion of the compression member of that support unit not connected thereto by one of said fiirther tensioned tension members.

Preferably, each of the compression members is made of turned wood, hollow plastics material, or steel or aluminium tubing, and the tension members are made of natural fibre or small diameter steel wire.

According to a third aspect, the present invention provides a method of making a support structure of the type defmed above, the method comprising the 25 steps of.

(a) fortning the tension members into a network constituted by a series of groups of interconnected tension members; (b) tensioning the tension members and the further tensioning members, the groups being interconnected by the further tension members; (c) positioning the compression members so that their end portions are interconnected in the manner defined; and (d) releasing the tension members so that the compression members are locked firmly in position to provide a substantially firm support structure.

According to a fourth aspect, the present invention provides a method of making a support structure of the type defined, the method comprising the steps of (a) forming the tension members into a network constituted by a series of groups of interconnected tension members, the groups being interconnected by the further tension members; (b) positioning the compression members so that their end portions are interconnected in the manner defined; and (c) tensioning the tension members and the further tension members by extending each of the compression members, so that the compression members are locked firmly in position to provide a substantially firm support structure.

Four forms of support structure, each of which is constructed in accordance with the invention, will now be described in greater detail, by way of example, with reference to the drawings, in which:

Fig. I is a schematic perspective view of the support system of a chair (the first form of support structure); Fig. 2 is viewed similar to that of Fig. 1, but showing the support system and the rest of the chair; Fig. 3 is a schematic perspective view of a tower (the second form of support structure); Fig. 4 is a perspective view of one unit forming part of the tower of Fig.

3; Fig. 5 is a perspective view of three units of the tower of Fig. 3; Fig. 6 is a side elevation showing detail A of Fig. 5; Fig. 7 is a perspective view of an extender of the tower of Fig. 3; Fig. 8 is a schematic perspective view of another tower (the third forTn of support structure); Fig. 9 is a perspective view of an arch (the fourth form of support structure); Fig. 10 is a schematic perspective view of a modified form of the tower of Fig. 3; and Fig. 11 is a perspective view of one unit of the tower of Fig. 10.

Referring to the drawings, Fig. 1 shows a chair support system constituted by four struts or legs (compression members) 1, four first wires 2, four second wires 3 and four third wires 4. The legs 1 are made of natural tree branches turned wood, hollow plastics, or steel or aluminium tubing, and the wires 2, 3 and 4 are tension members made of natural fibre or small diameter steel wire. Each leg 1 has a floor-engaging end portion la and an opposite end portion lb. Each wire 2 interconnects the floor-engaging end portion la of a given leg 1 to the opposite end portion lb of an adjacent leg. The wires 3 interconnect the end portions la of all four legs 1, and the wires 4 interconnect all four end portions lb of the legs.

The structure is generally 440 min square in plan, and has a height of 440 min.

In order to build the support system shown in Fig. 1, it is necessary to utilise a special jig (not shown). This is because, the legs 1 need to be held in the positions shown until all the wires 2, 3 and 4 have been connected under tension to the legs. Thus, until the last wire 2, 3 or 4 is connected at both its ends to the associated legs 1, the structure is totally unstable.

Once all the wires 2, 3 and 4 are connected to the legs 1 under tension, the jig can be removed, and a seat 5 (see Fig. 2) can be attached to the wires 4 at the upper end portions lb of the legs 1. The scat 5 could be a sheet of woven material, or could be made of leather or fabric.

The chair described above is an attractive piece of furniture using minimal materials, so that the cost of manufacturing a useful, multipurpose chair or stool is extremely low. In particular, it should be noted that such a chair can be manufactured without requiring any joints.

It will be apparent that modifications could be made to the embodiment described above. Thus, the article of furniture could be a simple table.

Fig. 3 shows schematically the second form of support structure (a tower) which is constituted by four support units U. As shown in Fig. 4, each unit U is constituted by three struts 11, and six wires 12. Three of the wires 12 interconnect the lower ends of the struts 11, and the remaining three wires 12 interconnect the upper ends of the struts. Adjacent units U of the tower are connected together by three second wires 14. The three wires 12 interconnecting the upper ends of the struts I I of one support unit U also constitute the wires interconnecting the lower ends of the struts I I of the adjacent support unit.

In order to construct the tower, the network of wires 12 and 14 is preformed as if it were a knitted garment. The wires 12 and 14 are then stretched so that the struts I I can be inserted into the network as shown in Fig. 5. Thus, adjacent struts I I of adjacent units U are connected by a pin 15 inserted into aligned apertures 14a formed in the adjacent end portions of the struts. Each pin 15 permits the associated struts I I to twist slightly relative to one another. Once all the struts I I are positioned, the tension in the wires 12 and 14 is then relaxed, so that the struts I I are locked firmly in place. The lower ends of the struts I I of the lowermost unit U is provided with brackets 16 for anchoring the tower to the ground. The struts I I are made of turned wood, plastics material, steel or aluminium, and the wires 12 and 14 are made of string, rope, carbon fibre, steel wire or any other suitable flexible tensioning member.

If it is necessary to tension the structure further, this can be achieved by using extenders E of the type shown in Fig. 7. One strut I V of each unit U is provided with an extender E. Each extender E is constituted by threaded rod 17 which has right-hand and left-hand screw threads 17a and l7b respectively at its two ends. A nut 17c is provided at the centre of the rod 17 between the two threaded portions 17a and l7b. In use, the threaded portions 17a and l7b mate 1 with correspondingly-threaded sockets I la and I Ib formed in (or fixed within) the adjacent end portions of the stnit I V which is of two-part form. A sleeve 18 covers the gap between the adjacent end portions of the strut 11'. By turning the nut 17c (for example by means of a spanner) the strut I V is extended to provide the required additional tensioning force.

The tower structure described above utilises flexible tension members (the wires 12 and 14) which, when 'woven' or 'knitted' form a box-like fiamework. This framework can be likened to a stocking membrane which can be rolled up and stored prior to the operation of fitting the compression members (the 10 struts 11).

The tower structure described above could be modified by providing every one of the struts with an extender E. The tower would then be erected by positioning the struts, and by tensioning the wires 12 and 14 by means of the extenders E. In this way, there is no need to over-tension the wires 12 and 14 to 15 permit the positioning of the struts 11.

The tower configuration can be altered to any shape required. For example, a tower shaped wider at the bottom that at the top (see Figure 8) or an arch (see Figure 9) can be formed by weaving the tension members to the required lengths. Complicated shapes could be made by using computergenerated 20 measurements for the tension members.

The tower described above with reference to Figs. 3 to 7 is a relatively flexible structure, and could be used as a purely decorative tower. For example, a tower of this type could constitute a form of sculpture, which would look well swaying in the wind, not unlike a tree moving in the wind.

On the other hand, if a more rigid structure is required, for example for a tower supporting floodlights, the structure should be rigidised. One form of rigid tower is shown in Figs. 10 and I I which show a modified form of the tower of Figs. 3 to 7, and use the same reference numerals for the same parts. Only the modifications will be described.

The basic difference between the two forms of tower is that the tower of Figs. 10 and I I includes an additional tension wire 18 in each support unit U.

As shown in Fig. 11, the additional tension wire 18 of each unit U extends between the lower end of one of the struts I I of that unit and the upper end of the other of the two struts of that unit not connected thereto by a tensioning wire 14.

The effect of the tensioning wires 18 is to triangulate the framework and tighten up what would otherwise be a relatively flexible structure.

The tower of Figs. 10 and I I requires accuracy in measuring the lengths of the struts I I and the tension wires 12, 14 and 18. As the structure has a certain amount of flexibility when the tension wires 12 and 14 are slack (that is to say before they are fidly tensional), it is important that all the elements are accurately measured, and are of consistent lengths. This is to ensure that a tower being used a an engineering structure (as opposed to a sculpture, for example) can be built vertical and straight within required tolerance. The tensioning wires 18 are effective to lock the configuration of Figs. 10 and I I into a rigid structure.

Either of the towers described above could be modified by changing the number of struts I I per support unit U. For example, each support unit could have four or five struts 11. Moreover, the struts I I of adjacent support units could be connected together by special joint connectors rather than by the pins 15, These joint connectors would provide connection points not only for the struts 11, but also for the tension wires 12, 14 and 18.

It would also be possible to produce other support structures in accordance with the invention. For example, a tensegrity tent could be made by using a support unit of the type described above with reference to Figures 3 to 7 as a framework for a tent covering.

Claims

CLAIMS:

1. An article of ftirniture constituted by at least three compression members each having first and second end portions, a plurality of tension members, and a load-bearing support member, the first end portion of each compression member being connected to the second end portion of an adjacent compression member by a respective tensioned tension member, the first end portions of each pair of adjacent compression members being interconnected by a respective tensioned tension member, and the second end portions of each pair of adjacent compressive members being interconnected by a respective tensioned tension member, the load bearing support member being fixed to the tensioned tension members interconnecting the second end portions of the compression members.

2. An article of furniture as claimed in claim 1, wherein there are four compression members and twelve tension members.

3. A support structure constituted by a plurality of support units joined together end-to-end, wherein each support structure is constituted by at least three compression members each having first and second end portions, the first end portions of each pair of adjacent compression members of each support unit being interconnected by a respective tensioned tension member, and the second end portions of each pair of adjacent compression members of each support unit being interconnected by a respective tensioned member, the first end portion of each compression member of a given support unit being connected to the second end portion of an adjacent compression member of that support unit and to the first end portion of a compression member of the support unit adjacent to the second end portion of said given support unit by a respective finther tensioned tension member, the ftirther tensioned tension members constituting the means for joining the support units end-to-end.

4. A support structure as claimed in claim 3, wherein the tensioned tension members interconnecting the second end portions of the compression members of one support unit constitute the tensioned tension members interconnecting the first end portions of the compression members of the adjacent support unit.

5. A support structure as claimed in claim 3 or claim 4, wherein the second end portion of each compression member of a given support unit is connected to the first end portion of the adjacent support unit by connection means permitting relative pivotal movement therebetween.

6. A support structure as claimed in any one of claims 3 to 5, wherein said adjacent end portions of two connected compression members are formed with aligned apertures, a pin engaging within said aligned apertures constituting said connection means.

7. A support structure as claimed in any one of claims 3 to 6, wherein the first end portion of a given compression member of each support unit is connected to the second end portion of the compression member of that support unit not connected thereto by one of said further tensioned tension members.

8. A support structure as claimed in any one of claims 3 to 7, wherein each of the compression members is made of turned wood, hollow plastics material, or steel or aluminiurn tubing.

9. A support structure as claimed in any one of claims 3 to 8, wherein the tension members are made of natural fibre or small diameter steel wire.

10. A method of making a support structure of any one of claims 3 to 9, the method comprising the steps of- (a) forming the tension members into a network constituted by a series of groups of interconnected tension members; (b) tensioning the tension members and the fin-ther tensioning members, the groups being interconnected by the ffirther tension members; (c) positioning the compression members so that their end portions are interconnected in the manner defined; and (d) releasing the tension members so that the compression members are locked firmly in position to provide a substantially firm support structure.

11. A method of making a support structure of any one of claims 3 to 9, the method comprising the steps of- (a) forming the tension members into a network constituted by a series of groups of interconnected tension members, the groups being interconnected by the further tension members; (b) positioning the compression members so that their end portions are interconnected in the manner defined; and (c) tensioning the tension members and the fin-ther tension members by extending each of the compression members, so that the compression members are locked firmly in position to provide a substantially firm support structure.

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