GB2254864A - Collapsible structural framework - Google Patents

Abstract

Collapsible framework for use in portable or other structures comprises non-folding ribs (10) and folding ribs (12) having releasable hinge joints (14) at their centres. The ends of the ribs are interconnected by pivotal or hinge joints at the apices (A-F) of tetrahedral cells constituted by the erected ribs, each cell including two folding ribs (12) between different pairs of its four apices enabling the structure to be collapsed so that sets of apices can be folded together bringing the ribs into a compact bundle without disconnection of any of the rib joints. The framework may be that of a tent, or may constitute a collapsible beam or the like. <IMAGE>

Description

STRUCTURAL FRAMEWORK This invention relates to structural frameworks particularly but not exclusively of a light duty nature e.g. for commercial or other display stands, tents, and other indoor or outdoor temporary or dismountable structures though it is anticipated that the invention may also have application to heavier duty temporary or portable structures such as framework for buildings or lattice type pillars, beams or trusses e.g. for cranes or bridges, and/or to structural frameworks which can be extended and retracted for applying force or displacing a load.

The object of the invention is to provide a simple and adaptable self-contained framework which is strong and reliable in use, which can be erected, extended or retracted speedily and simply, and which can be readily converted to a compact condition for storage or transport without dismantling individual components.

cording to one aspect of the invention a tetrahedral framework for use as or in a portable or other structure comprises load carrying members hingedly connected at their ends whereby the or each tetrahedral cell of the structure is defined by six of said members characterised in that two of the members defining the or each said cell are each provided with an intermediate joint permitting selective folding to bring the ends of that member towards each other whereby the structure can be selectively collapsed by bringing pairs of apices of the or each cell into adjacent relationship.

In another aspect the invention provides a multicell tetrahedral space framework of rectilinear rigid ribs in which every triangular frame comprises one rib section which is selectively collapsible from its rectilinear operative condition enabling the whole framework to be folded into a compact $assembly without disconnection from each other of any of its component ribs.

Some examples of the invention are now more particularly described with reference to the accompanying drawings in which : Figure 1 shows a three cell tetrahedral space framework in erected condition, Figures 2, 3 and 4 show successive stages of folding said framework for storage or transport, Figure 5 shows a larger tetrahedral framework in erected condition, and Figure 6 shows the latter framework in folded condition.

Referring firstly to Figures 1-4 the framework shoun comprises three tetrahedral cells defined by twelve operatively rectilinear load carrying members or ribs and it will be appreciated that sore of the ribs are common to more than one cell.

The ribs, which may be rods, tubes or other sections, are of two kinds non-folding ribs 10, and folding or collapsible ribs 12 which are in two parts linked end-to-end by a hinge joint 14 at their centres enabling them to be locked in rigid rectilinear condition as shown in Figure 1 or, by releasing a catch, sliding collar or other securing device, to be folded so as to bring their ends together as shown in Figures 2-4.

The ends of the ribs 10,12 are interconnected by pivotal or hinge joints at the apices A-F of the cells.

These joints are permanent in the sense that the ends of the ribs 10,12 are not normally disconnected from each other in service i.e. the individual components of the framework do not have to be dismantled for erection or folding of the structure.

Each cell includes two of the collapsible ribs 12 between different pairs of its four apices, for example the cell on the left of Figure 1 which is best visible in the drawings has the four apices A-D of which A-B and C-D are directly linked by collapsible ribs 12 with the remaining ribs defining that cell being non-folding ribs 10.

Folding rib D-C is also common to the next adjacent cell A C D E which also has folding rib A-E and so on.

Looked at in another way every triangular frame throughout the structure which form the sides of the cells will consist of two non-collapsible ribs 10 and one collapsible rib 12, for example triangle A B C.

This arrangement of the collapsible ribs 12 enables the entire framework to be simply folded and re-erected in a speedy and reliable manner. The stages of folding from the erected condition of Figure 1 are illustrated in sequence in Figures 2-4. Some only of the ribs and hinge joints have been given reference numbers in these drawings to avoid confusion.

Looking first at Figure 2 and again considering the lefthand cell ABCD, rib AB is being folded inwardly so that apices AB of the cell can be swung towards each other. At the same time, by the folding of rib 12 between C and D the latter apices are closed together.

Continuing the process folds the entire framework through the Figure 3 state to the compact condition of Figure 4 in which sets of apices B, A, E and De C, r are brought together, and all the ribs 10 and all the folded together sections of the collapsible ribs 12 are brought into adjacent substantially parallel relationship to form a bundle which can be secured by a carrying strap and/or placed in a bag or other covering for compact storage and transport.

Erection is a reversal of the above process and it will be noted that there are no loose components or fastenings which may become lost or displaced and no need to provide for complex and not always reliable releasable connections or couplings at the apices, nor can there be any confusion as to assembly or the correct relationship of the components.

It will be appreciated that the above principles can be incorporated into any size of structure and/or structures having an infinite number of tetrahedral cells. A larger framework doubling the number of cells to form e.g. a longer ridge tent framework for a truss type beam or pillar is shown in Figure 5, the same principles of its construction and folding and unfolding apply through the cells defined by the further ribs 10 and 12 forming additional apices G, H, and I the folded condition being shown in Figure 6.

Even larger structures can be built using two or more frameworks of the invention as sub-assemolies which are coupled or otherwise linked together in use.

It is to b understood that the collapsible ribs may, in some applications, fold outwardly rather then inwardly of the triangular frame of which it forms part.

It is also to be understood that a framework may comprise ribs of non-uniform length so that its bounding edges, or some of them, on erection are non-rectilinear.

e.g. to provide a structure defining a generally cylindrical or part-cylindrical, or spherical or partspherical envelope, or other regular or non-regular shape.

Erection and/or retraction of the framework may be either direct or indirect by way of devices providing a mechanical advantage, be manual, or may be powered or power-assisted. Resilient means such as springs may also be incorporated to urge the ribs to their extended condition or to assist in folding or retraction.

Powered or power-assisted operation or indirect manual operation may be by incorporation of one or more screw or lever jacking devices and/or by fluid pressure devices such as hydraulic rams or struts.

Particularly where powered or power-assisted operation is provided, or where manual indirect operation with mechanical advantage is provided a framework of the invention may be employed for transmitting or applying a force or displacing (e.g. raising and lowering) a load.

Thus the framework may itself be employed as a jacking or bracing device. An extendable and retractable towers e.g. for a work platform, or an extendable and retractable load carrying jib might be provided in this way.

Claims (5)

1. A tetrahedral framework for use as or in a portable or other structure comprising load carrying members hingedly connected at their ends whereby the or each tetrahedral cell of the structure is defined by six of said members; characterised in that two of the members defining the or each said cell are each provided with an intermediate joint permitting selective folding to bring the ends of that member towards each other whereby the structure can be selectively collapsed by bringing pairs of apices of the or each cell into adjacent relationship.

2. A fram.eworik as in Claim l comprising 2 plurality o tetrahedral cells some of the members being common to more than one cell.

3. A framework as in Claim 2 wnerein said folding brinks sets of the apices respective to each cell together with all the non-folding members and all the folded together sections of the collapsible members brought into adjacent substantially parallel relationsli? to for: an ordered compact bundle.

4. A framework as in Clain 1. 2 or 3 wherein all the members are of uniform length when erected.

5. A tetrahedral framework substantially as hereinbefore described with reference to and as shown in Figures 1-4; or Figures 5 and 6 of the accompanying drawings.

5. A -lulti-cell tetrahedral space framework of rectilinear rigid ribs in which every triangular frame comprises one rib section which is selectively collapsible from its rectilinear operative condition enabling the whole framework to be folded into a compact assembly without disconnection from each other of any or its component ribs.

6. A framework as in Claim 5 comprising one or more longitudinally extending series of cells providing a truss type beam or pillar on erection.

7. A structure comprising two or more franeworis as defined in any preceding claim.