The present specification relates to folding structures, particularly though not exclusively buildings and shelters.

It is very desirable structures that can be used for shelter, storage or other uses can be stored or transported in a compact folded configuration, and then expanded into a usable structure in the location where they are to be deployed. There are many such known designs. Ideally, a folding structure should fold to a very compact shape, not have too many parts or be too complex or expensive, and be capable of being unfolded and erected quickly with minimal tool use or expertise. Many of the known designs do not perform well in one or all of these criteria.

The present invention seeks to provide a folding structure that addresses these problems.

According to the present invention, there is provided a folding structure according to claim 1.

The invention will now be described, by way of example, with reference to the drawings, of which

Figure 1 is a perspective view of the folding structure in a folded state; Figure 2 is a side elevation of the folding structure in a folded state;

Figure 3 is a perspective view of the folding structure as it is being unfolded;

Figure 4 is a side elevation of the folding structure as it is being unfolded;

Figure 5 is a perspective view of the folding structure as it is being unfolded;

Figure 6 is a side elevation of the folding structure as it is being unfolded; Figure 7 is a perspective view of the folding structure as it is being unfolded;

Figure 8 is a side elevation of the folding structure as it is being unfolded;

Figure 9 is a perspective view of the folding structure as it is being unfolded;

Figure 10 is a side elevation of the folding structure as it is being unfolded; Figure 11 is a perspective view of the folding structure in an unfolded state;

Figure 12 is a side elevation of the folding structure in an unfolded state;

Figure 13 is a side elevation of a detail of the folding structure in an unfolded state; Figure 14 is a perspective view of a shelter using several folding structures;

Figure 15 is a perspective view another embodiment of the folding structure as it is being unfolded;

Figure 16 is a perspective view of a shelter using several of these folding structures.

Figure 16b is a perspective view of another shelter using several of these folding structures;

Figure 17 is a perspective view another embodiment of the folding structure in its folded state;

Figure 18 is a side elevation the folding structure in its folded state; Figure 19 is a perspective view the folding structure unfolding;

Figure 20 is a side elevation the folding structure unfolding; Figure 21 is a perspective view the folding structure fully unfolded;

Figure 22 is a side elevation the folding structure fully unfolded;

Figure 23 is a side elevation showing a detail of a joint of the folding structure fully unfolded;

Figure 24 is a perspective view showing a detail of the joint of the folding structure fully unfolded; Figure 25 is a perspective view showing a detail of the joint of the folding structure partially unfolded;

Figures 26 and 27 are a perspective views showing details of the joints of the folding structure when nearly fully folded;

Referring to figure 3, the folding structure comprises a set of panels 1, which are connected together by arms 2. In each of the figures, there are depicted three panels connected by six arms, but as will be explained below, the number of panels (and therefore the number arms) can be varied. The arms 2 are attached to each panel in pairs, at matching points either side of each of the panels. In general, each panel 1 is pivotally connected to its neighbouring panels by three of pairs of arms 2; one pair of arms 2 is joined to the panel near the mid-point both of the length of the panel and the length of the arms, by central hinge pin 4. The other two pairs of arms 2 are joined by their ends to the ends of the panel 1 by end hinge pins 3.

Each panel in general is pivotally attached to three pairs of arms; each pair of arms is pivotally attached to three panels. Referring to figure 4, in this way, the panels and arms together form a repeater scissor or lazy tong formation.

The panels and arms at the end of each structure will have fewer connections. The first and last panels 1 will only be attached to two arms 2, by one central hinge pin 4 and one end hinge pin 3, and each panel will have one end which is free and unattached to a pair of arms. Similarly, the end arms will only by connected to two panels; the end arms will typically be truncated, so that they do not extend between the two hinge pins they are pivotally attached to.

The central hinge pin 4 need not be situated precisely at the mid-point of the panel, or the mid-point of the arm 2. Rather it can be offset or displaced, to a small degree. Referring to figure 4, the central hinge pin 4 is here displaced slightly towards the right end (as one views the figures) of both the panels 1 and the arm 2, so that the distance a between the central hinge pin 4 and the left end of the panel 1 is greater than the distance b between the central hinge pin 4 and the right end of the panel 1. The position of the central hinge pin 4 similarly divides arm 2 a left portion of length a and a right portion of length b. Figures 1 and 2 show the most compact configuration of the folding structure. The panels are all lying against each other, with their faces substantially abutting. Similarly, the arms 2 are lying against each other, with their edges abutting. It will be seen that the arms are slightly inclined with respect to the panels.

In order to erect the structure, the edge of the free end of the uppermost panel is gripped and lifted up. The weight of the structure keeps the lower panel on the ground and the other components generally depending from the lifted edge. The relative movement of the other panels 1 and the arms 2 connecting them is constrained however, and the structure starts to unfold as the edge of the free end of the uppermost panel is raised, as shown in figures 3 and 4. Referring to figures 5 and 6, as the edge of the free end of the uppermost panel is raised further, the structure progressively unfolds, the panels 1 and arms both becoming more includes (but in opposite directions) with respect to the ground. Figures 7 and 8 show this unfolding at a further stage, with the panels and the arms inclining towards a vertical position.

As previously described, the length of the central hinge pin 4 and the left end of the panel 1 , and the length of the central hinge pin 4 and the left end of the arm 2 are both length a, while the length of the central hinge pin 4 and the right end of the panel 1 , and the length of the central hinge pin 4 and the right end of the arm 2 are both length b. Since length a is greater than length b, the structure starts to curve as it is unfolded, so that the top of the structure shown in figure 8 is inclined to the right. The relative movement of all the parts is constrained, with a single degree of freedom. Therefore, forcing a relative movement between any two parts will cause the rest of the structure to move. So, raising the edge of the free end of the uppermost panel while the weight of the structure acts on the other parts, tends to unfold the whole structure. The structure may be unfolded by other means though, and when it is partly unfolded, as shown in figure 5 and 6, it may be more convenient to force the end hinge pins of two neighbouring panels (the lower end hinge pin of one panel, and the upper end hinge pin of the other panel) towards each other, and the constrained nature of the structure will cause further unfolding.

By the time the structure is unfolded to the extent illustrated in figures 9 and 10, since the length of the central hinge pin 4 to the and the right end of the panel 1 (which is and end hinge pin here designated 3'), and the length from the left end of the arm 2 attached to end hinge pin 3' to the next central hinge pin 4' are both made up of the shorter length b, it will be seen that these sections are nearly collinear and the angle between the arm 2 and panel 1 at end hinge 3' is approximately 180°. The structure is now curving noticeably.

Referring to figures 11 and 12, as the structure continues to unfold, arm 2 and panel 1 which pivot about end hinge 3' has now overcentred and started to fold back on itself, until the end of one arm abuts against the end the next arm. Referring to figure 13, as the arm 2 and panel 1 which pivot about end hinge 3' over-centre, a corner 6 of arm 2 abuts against a point 5 on the lower edge of the next arm 2'. This locks the structure against further movement, and represents the fully unfolded state shown in figures 10 and 11.

The angle between successive panels is therefore determined by the previously identified lengths a and b into which each arm and each panel is divided, and further by the thickness of the arm 2' and the thickness and the length beyond the pin 3' of arm 2, these dimensions determining when the structure locks together. Optimum values may be determined mathematically, graphically or using CAD software, or even experimentally, since some amount of play in the system can alter the angles. It will also be seen that the shape, particularly of the corner 5 of the arm 2' could be altered to modify the angle.

The angle between successive panels is chosen curvature for the structure, taking account of the number of panels. To form a half arch structure as shown in figure 11, the angle a between successive panels is chosen to be 30°, and the angle for n panels would be 90/n.

Successive panels are here shown overlapping each other; referring to figure 13, the end of the panel 1 at end hinge 3 overlaps the end of the panel at end hinge 3'. This arrangement allows ventilation without permitting rain ingress. The ends of the panel 1 and panel could alternatively be arranged to abut with a tight fit or seal. Further, the locking constraint here shown being provided by the abutment of the two arms 2, 2', could alternatively or additionally be provided by the two panels 1, 1'.

Referring to Figure 14, two similar half arches 10, 11 may be erected facing one another to form a complete arch 15, and then secured along their abutting top edges to form a ridge 16. Several such full arches 12, 13, 14, 15 may then be placed edge to edge to make a longer, generally semi cylindrical structure 20. The ends of the structure may be blocked off, for example by attaching end walls 17, attached to the folding arms and panels if necessary. The panels may of any rigid material, and may comprise or include transparent material such as polycarbonate. Other possible materials include polypropylene honeycomb sandwiched between different laminate materials, such as Kevlar.

The full arches 12, 13, 14, 15 may be made progressively smaller, so that each one can slightly overlap the next, or even allow the whole building to be telescoped with the arches nesting within one another.

The two half arches may be joined at the ridge by some fastening means. The opposing edges of the panels could also be shaped, for example in a tongue and groove, so that one panel edge locates in the other panel edge. The weight of each half arch will tend to press the half arches together, giving the structure an inherent stability. One end of one the half arch could overlap the end of the abutting half arch. Referring to figure 15, the principle creating a folding structure using panels and arms could be extended by pivotally attaching a first set of panels 21 to one set of arms 23, and a second set of panels 22 on the other side of the arms 23. Referring to figure 16, half arches 24, 25, 26, 27 so formed can be formed into a tunnel structure in a similar manner to that previously described. Indeed, the arms could be replaced by further set of panels, joined to the first set of panels directly using end hinge pins and central hinge pins pivotally joining the two sets of panels in the same way as that articulation described between a set of panels and a set of arms. Referring to figure 16b, by making the panels trapezoid and triangular (with the triangular panel at the top), folding structures 42, 43, 44, 45 may be created which form hemispherical or half-hemispherical shapes, which may be used alone or attached to the half arches 46, 47, 48 already described. Since each edge of the panels of any one of the folding structures 42, 43, 44, 45 will fold in different planes, it will be necessary to use a single set of arms, either alone or joined between two panels such as shown in figure 15. So the two sets of panels 21, 22 which each be trapezoid, and the uppermost panel on both set 21 and set 22 would be triangular. Each half arch is here shown as generally lying on an arc of a quadrant, so that two half arches together form a generally semicircular shape. The half arches may though each form either more, or less, than the segment of a quadrant, in which case the resulting structure may form a segmented arch similar to a Gothic arch shape. Also, panels and arms may be numbered and arranged so that a single structure unfolds to a semicircular shape. The locations of the end hinge pins and centre hinge pins along the panel and along the arms, particularly the distance along the length of the panel and the arm, may be varied in order to vary the curvature. Different panels and arms may have their end hinge pins and centre hinge pins located at different points within a single folding structure, so that the curvature or shape of the unfolded arch varies along its length.

A useful application for the folding structure is for emergency and disaster relief shelters, where the compact design can be easily transported and erected. It is also easy to dismantled and fold up again when no longer needed. This makes it ideal for temporary structures such as tents, marquees. It can be straightforwardly utilised for many situations where an arched structure is required, such as sheds, greenhouses, animal pens etc. It can also be incorporated with a car, camper van or caravan. It can be used for storage, privacy, cover, or workspace/area pardoning both indoors and outdoors.

A typical panel size might be 1200mm x 800mm x 20mm, and when these dimensions are used in three panel structure as shown in figures 1-13, two such half-arches brought together can create an arch for a structure having a height of 2m and a span of 4m. The total space taken up by the two half-arches when folded is 1200mm x 800mm x 140mm. This represents a considerable space saving for a solid panelled structure especially when used in a disaster relief situation where the structure would need to be transported by plane, boat or on land. The panels can conveniently have the arms extending along their length, or the panels and arms can be formed as an integrated unit. However, panels of other covering may be attached to the linkage structure at a later stage, or a panel may be attached to more than one arm, or such that the linkage mechanism is not co-incident with the panel side. The pivots of the linkage mechanism may be positioned to occur at any point along the panel to which it is or will be attached (either along it's height, or along it's width). The folding structure could form a framework for some other covering instead of or together with panels.

The folding structure allows for rapid deployment of the structure and could be achieved by one person, particularly when lightweight panels are used. Once the half arches are brought together, the structure is self-supporting, so that few constructions tools or additional parts are required, reducing the risk of parts being lost and the structure not being able to work.

The pivoting mechanism is here described as being enabled by hinge pins. It will be realised that any mechanism that allows the panels and arms to pivot about particular points in the manner described could be utilised.

Although the above folding mechanism particularly shown in figures 1 to 13 shows an unequal division either side of the hinge pin (i.e. that the distance a between the central hinge pin 4 and the left end of the panel 1 is greater than the distance b between the central hinge pin 4 in figure 8), this shaped formed on extending the folded mechanism may be achieved or constrained in other ways. Referring generally to figures 17 to 27, an alternative folding structure 30 is shown. Figures 17 and 18 show the structure 30 in its fully folded state. In this embodiment, the distances a and b either side of the hinge pins 34 are (or may be) equal in length. Instead, there is enough play in the folding mechanism such that, when unfolded, the structure will lean or curve to form an arch as shown in figures 19 and 20 in an intermediate stage, and figures 21 and 22 in a final stage. Referring to figures 23 and 24, the structure shown here also incorporates a bracket 28 attached to at least some of the end hinge pins 33 (specifically, attached to alternating end hinge pins). These brackets support the arms 31 when they are in final unfolded position, and constrain the final unfolded position, determining the unfolded angle between the arms (and so the shape of the arch).

Referring to figure 25, the brackets are attached to one set or half of the end hinge pins 33'. The ends 3 of the arms are spaced, and their hinge pins 33' split. The end 3 of each arm has a rabetted shape or joint, the extended portion of each end being joined by its respecting split hinge pin 33' to the bracket 28. The other set or half of the end hinge pins 33" does not include a bracket 28, but the ends 31" are also rebated, with the two extended portions being joined directly together with a single hinge pin 33". Referring to figure 24, as the structure is unfolded, and each set of arm ends 31 ' comes together with each set of arm ends 31", the rebated ends of the arm ends 3 and 31" allow the arms to slot together, so that four arms are then supported and constrained by a bracket 28.

Figure 26 shows set of the end hinge pins 33' and the bracket 28 close to being fully folded, and figure 27 shows set of the other end hinge pins 33" also close to being fully folded, where the rebated nature of the ends can be clearly observed.

It will be realised that there are many ways in which the arms (or panels, if they incorporate the arms) can be joined together or otherwise hinged so that they pivot about each other to unfold, and many ways in which the hinged or folding nature can then be constrained so that the an angle reached to define the arched shape of the shelter.