Protective shelter   

Abstract: A protective shelter is provided offering opposite outer supports and a roof structure extending between the supports, wherein the roof structure comprises a first layer covering a space between the outer supports and providing a first level of protection to the shelter and a second layer in the form of a pre-detonation screen providing a second level of protection to the shelter, wherein the pre-detonation screen comprises a plurality of individual panels arranged and supported over and spaced from the first layer, at least one of the individual panels comprising a first panel material presenting a substantially closed surface to an incoming projectile and at least one second panel material forming an edging strip to the first panel material and being of greater rigidity than the first panel material.

The present invention relates to a protective shelter and, in particular, to such a shelter that can provide protection within a war zone and which can be readily assembled in a quick, secure and reliable manner.

While a variety of requirements arise for temporary, or at least quickly-built shelters, there is generally a compromise between the level of protection offered by the shelter and the speed, reliability and ease with which such a structure can be built.

Also, the degree of protection required by the shelter can change over time and known protective shelters, while perhaps providing an appropriate initial level of protection, may not be suited to a scenario in which a lesser, or greater, degree of protection is required.

Our co-pending applications PCT/GB2008/050275 and PCT/GB2009/051431 describe certain types of shelter which utilise a shallow-arched roof structure to provide support for a ballast material to protect the shelter from explosive attack.

However, we have now developed certain improvements to these structures, particularly although not exclusively with reference to pre-detonation screens for such structures and to certain structural improvements allowing for greater strength and greater ease of manufacture and assembly, and this invention consequently seeks to provide for a protective shelter having certain advantages over known such shelters.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 shows a panel formed from a first panel material, to be used in the construction of a pre-detonation screen according to a first aspect of the invention;

FIG. 2 shows an edge element formed from a second panel material for providing an edging strip to the panel shown in FIG. 1;

FIGS. 3, 4 and 5 show photographs of the shelter of the invention in construction at the stage of assembly of the pre-detonation screen;

FIG. 6 shows a connecting element for connecting purlin components together in the construction of a pre-detonation screen according to a second aspect of the present invention;

FIG. 7 shows a rafter component;

FIG. 8 shows a purlin component;

FIGS. 9 and 10 show photographs illustrating the insertion of the connecting element of FIG. 6 into the rafter component of FIG. 7;

FIGS. 11 and 12 show anchor beam components use in the construction of a roof structure according to a third aspect of the invention; and

FIGS. 13 and 14 show photographs of a shelter in accordance with the invention at the stage of construction of the anchor beam assemblies.

DETAILED DESCRIPTION

As will be appreciated from the following description, examples of a shelter embodying the present invention can be quickly and, importantly, reliably constructed in a manner requiring a minimum number of personnel and, critically, in a manner such that each separate component of the structure can be removed and lifted, preferably single handedly.

Also, all separate components can advantageously be of a size such that they are readily transportable, in flat-packed unassembled form on a pallet, such as a pallet of dimensions 2 metres×2.2 metres, preferably on a pallet of dimensions 1.2 metres×1.2 metres.

According to a first aspect of the present invention, there is provided a protective shelter offering opposite outer supports and a roof structure extending between the supports, wherein the roof structure comprises a first layer covering a space between the outer supports and providing a first level of protection to the shelter and a second layer in the form of a pre-detonation screen providing a second level of protection to the shelter, wherein the pre-detonation screen comprises a plurality of individual panels arranged and supported over and spaced from the first layer, at least one of the individual panels comprising a first panel material presenting a substantially closed surface to an incoming projectile and at least one second panel material forming an edging strip to the first panel material and being of greater rigidity than the first panel material.

The primary purpose of the pre-detonation screen is to cause an incoming explosive projectile to detonate on the pre-detonation screen and not on the first layer of the roof structure. Typically, in the event of such an attack the pre-detonation screen acts as a sacrificial layer, protecting the first layer from the primary detonation of the projectile. Our co-pending applications PCT/GB2008/050275 and PCT/GB2009/051431 describe briefly the use of pre-detonation screens, typically of plywood, but we have now found that an improved form of pre-detonation screen may be obtained by the use of composite panel elements making up the screen, wherein those elements or any of them comprise a first panel material presenting a substantially closed surface to the incoming projectile and at least one second panel material forming an edging strip to the first panel material and being of greater rigidity than the first panel material. Exemplary materials for the first and second panel materials include woods, plastics, metals and composites. However, the second panel material should be selected to have greater rigidity than the first. In this way, the risk of gaps appearing in the pre-detonation screen as it is subjected to warping and flexing, particularly when deployed in harsh climatic conditions, is minimised. One preferred material for the first panel material is wood, especially plywood, and one preferred material for the second panel material is metal, especially aluminium, and from now on in this specification we shall make reference only to those especially preferred materials. It will however be easily understood that the selection of appropriate alternative materials is well within the capability of the skilled addressee.

Preferably the second panel material is of greater shear strength than the first panel material.

Preferably the second panel material is of greater tensile strength than the first panel material.

Preferably the second panel material is less brittle than the first panel material.

Preferably the second panel material is of greater smoothness than the first panel material, allowing an improved and seamless fit between neighbouring panels of the screen.

Also preferably, the first panel material forms a panel and the second panel material forms an edging strip to the panel. The edging strip may be formed on one or more edges of the panel, preferably on at least two edges of the panel. The edging strip may be continuous or discontinuous. Its primary function is to reinforce the edges of the panel to prevent warping and bending of the panel in deployment and the consequent appearance of gaps in the pre-detonation screen through which an incoming projectile may pass.

The edging strip is preferably formed by at least one pre-detonation screen edge element formed from the second panel material. Preferably the pre-detonation screen edge element comprises a channel into which an edge of the panel may be received. Even more preferably, the pre-detonation screen edge element comprises two opposed channels into which the edges of two neighbouring panels may be received. The channels may oppose each other directly in a flat pre-detonation screen section or may be offset to allow and arched pre-detonation screen section to be constructed.

According to a second aspect of the present invention, there is provided a protective shelter offering opposite outer supports and a roof structure extending between the supports, wherein the roof structure comprises a first layer covering a space between the outer supports and providing a first level of protection to the shelter, and a second layer in the form of a pre-detonation screen providing a second level of protection to the shelter, wherein the pre-detonation screen is supported above the first layer by a plurality of rafters extending from the first layer and by a purlin supporting at least a plurality of the rafters, the purlin comprising a plurality of individual purlin components overlapping with and staggered with respect to one or more neighbouring purlin components and connected together by one of more connecting elements to form a continuous but staggered purlin.

The provision of a purlin supporting a plurality of the rafters provides important advantages in terms of the structural stability of the roof structure generally and the pre-detonation screen in particular. It also enables the entire roof structure to be pre-assembled before being lifted by crane onto the opposite outer supports. This enables construction of the roof structure at a remote location, perhaps away from incoming fire or from other hostile activity, or simply away from a place of exposure.

The connecting elements preferably have a plurality (usually two) of channels for receiving the purlin components. Generally, those channels will be adjacent one another. The connecting element is also preferably provided with a flange element for insertion into, or connection to, the rafter beam to secure the connecting element in place. Typically the rafter beam comprises a plurality of rafter beam components which are arranged end to end to form the rafter beam, with connecting elements inserted at the interstices between rafter beam components. When the connected element is mounted between two rafter beam components in this way, it preferably comprises a pair of opposed flanges for respective insertion into, or connection to, neighbouring rafter beam components. Staggering the components of the purlin with respect to each other has the important benefit in this case that it enables the connector elements to be made by extrusion since the width of the flange element for insertion into the rafter is substantially the same as the length of the each channel receiving the purlin components.

Thus, preferably the connecting elements comprise a plurality of channels for receiving the purlin components. Also preferably, the connecting elements comprise at least one flange for insertion into the rafter beam. Preferably the width of the flange and the length of the channel are substantially the same, enabling the connecting element to be manufactured by extrusion, particularly if the element is of metal or plastic construction. Aluminium is the preferred material.

According to a third aspect of the present invention, there is provided a protective shelter offering opposite outer supports and a roof structure extending between the supports, wherein the roof structure comprises a first layer covering a space between the outer supports and providing a first level of protection to the shelter, and a second layer in the foiin of a pre-detonation screen providing a second level of protection to the shelter, wherein the first layer is supported on at least one of the outer supports by an anchor beam comprising a first longitudinal beam element comprising a plurality of anchor beam components arranged end to end and a second neighbouring longitudinal beam element side by side with the first element and comprising a plurality of anchor beam components arranged end to end, joints between individual anchor beam components of the first longitudinal element being staggered with respect to joints between individual anchor beam elements of the second longitudinal element.

The provision of a plural longitudinal beam elements has been found to offer significantly greater structural stability to the roof structure generally and the pre-detonation screen in particular. Preferably the first longitudinal beam element is formed from a plurality of first (outer) anchor beam components, each component laying substantially flat on the outer supports but offering an inclined channel for receiving panel elements of a pre-detonation screen. Preferably the second longitudinal beam element is formed from a plurality of second (inner) anchor beam components, each component laying substantially flat on the outer supports and adjacent the components of the first beam element, but with the joints therebetween staggered with respect to each other. First and second longitudinal beam elements may be secured together by transverse beams forming the first layer of the roof structure.

Preferably the first layer of the roof structure comprises a plurality of tray members arranged to receive earth, sand or aggregate material defining an inner skin to provide a first level of protection in the roof structure, and the tray members are arranged to be supported by transverse beams, wherein the transverse beams are arranged to be supported at their respective ends by the opposite outer supports. The transverse beams may form a transverse beam bridge across the shelter such that the height of the shelter centrally, and away from the opposite supports is substantially the same as the height of said supports. Alternatively, the beams may be arranged to define a shallow arch across the shelter such that the internal height of the shelter centrally, and away from the opposite supports is greater than the height of said supports.

In order to assist the quick and reliable formation of such a bridge structure, the supporting transverse beams members advantageously comprise transverse beams of identical shape and configuration. Each transverse beam member may comprise a plurality of transverse beams joined together end-to-end by any suitable connecting means, such as one or more flitch plates for example. In the case of an arched bridge structure, the ends of each transverse beam member may be chamfered so as to connect end to end to form an arched section.

A greater plurality of beam members—for example three, four or five—may be provided end-on end, with suitable connecting members; although in this case it may be necessary for the shelter to be provided with one or more internal stanchions for supporting the roof beam assembly.

In a preferred embodiment, each transverse beam is provided by two transverse beam members joined end to end. Preferably, each transverse beam member is identical. Preferably, a vertical member of the transverse beams includes sections to accommodate flitch plates, for supportively connecting the transverse beams. Preferably still, the sections are controlled tolerance channels in the transverse beams. Advantageously, securing the transverse beams with the flitch plates in this manner creates a strong continuous transverse roof beam.

Preferably, each roof beam member is joined end-to-end with its paired roof beam member in a manner which provides a continuous straight-line or arched join.

The ends of the transverse beams are arranged to be supported by the outer supports, and may be advantageously be arranged to be connected to anchor beam components on the outer supports.

The anchor beam components advantageously serve to space the transverse beams along the length of the shelter and are arranged such that each transverse beam is effectively connected to, in a secure manner, adjacent anchor beam components. Advantageously, a the anchor beam components are arranged along the opposite outer supports to form an anchor beam comprising a first longitudinal beam element comprising a plurality of anchor beam components laid end to end, and a second neighbouring longitudinal beam element side by side with the first element and comprising a plurality of anchor beam components arranged end to end, the joints between individual anchor beam components of the first longitudinal element being staggered with respect to joints between individual anchor beam elements of the second longitudinal element. Preferably the transverse beams are connected to anchor beam components in both the first and the second longitudinal beam elements.

In any case, the anchor beam components, through their secure engagement to the transverse roof beams, provide for a rigid footing/support structure that extends along the length of the upper surface of the walls of the shelter and thereby combine to effectively define a lintel transverse beam extending along the length of the wall. Such rigid supporting structure provided by the anchor beam serves to define the aforementioned lintel transverse beam in a manner such that, should the outer wall suffer damage, or the integrity thereof be in any way compromised, the rigidity and stability of the overall roof structure can remain intact advantageously serving to retain the roof structure in place in spite of any such damage to the wall(s).

The structure of the invention can advantageously include a second laterally extending layer, spaced from the tray members and arranged so as to define a pre-detonation screen. The pre-detonation screen preferably comprises a plurality of individual panels arranged and supported over and spaced from the first layer, at least one of the individual panels comprising a first panel material presenting a substantially closed surface to an incoming projectile and at least one second panel material forming an edging strip to the first panel material and being of greater rigidity than the first panel material.

The pre-detonation screen is advantageously spaced from the initial layer formed by the tray members and the soil, sand, aggregate layer by a distance in the order of from about 0.5 metres to about 2 metres, for example.

Preferably, the tray members comprise a series of inter connected identical tray members having mutually connectable engagement formations at opposite ends thereof.

Preferably each tray member comprises a plurality of tray sections. Each tray section may be separated from its neighbouring tray section by a stiffening flange to give extra structural robustness to the tray member.

As a further feature, the portions of the roof structure provided above the earth, sand or aggregate layer can advantageously be formed from the inter connected metal poles, for example such as scaffold poles.

Such poles are arranged to provide roof trusses and rafter poles, within the overall structure of the roof. As one example, the pre-detonation screen can comprise plywood panels having a thickness of 19 mm.

As should be appreciated from the above, and from the description below, the invention is particularly advantageous insofar as the roof structure can be readily formed on gabion units which are arranged to form the opposite walls of the shelter.

The wall structures can be formed from structural blocks such as those that are the subject matter of European patent 0466726, European patent 1951963 or European patent application 06779610.2. Continuous wall structures, and other types of modular wall structure (concrete blocks for example) are also contemplated. Particularly preferred wall structures are of the type described in European patent 1951963, namely that at least one wall structure is formed from a gabion comprising opposed side walls comprising a plurality of side wall elements connected together at spaced intervals by a plurality of partition walls such that spaces between neighbouring pairs of partition walls define, together with the side walls, individual compartments of the gabion, adjacent side and partition walls being connected to one another by pivotal connections enabling the gabion to be folded between fully flattened and deployed configurations, wherein at least one of the pivotal connections is a releasable connection which when released allows a side wall element to open with respect to the gabion to allow access from the side of the gabion to any contents of the gabion compartments. Such gabions are openable to facilitate dismantling or repair.

In a particularly preferred arrangement for providing additional strength to the shelter, when the outer supports comprise gabion units, stanchions may be situated in one or more of the gabion units, providing additional support between the ground and the roof structure.

The overall protective shelter can then be quickly and reliably constructed as required, and in a manner responsive to the level of danger faced, and the level of protection required.

For example, once the gabions are in place to form the walls of the shelter, the roof structure can be readily, reliably formed, requiring a minimal number of personnel and, through use of the component parts described herein, in a structurally rigid and reliable manner so as to first provide a basic level of blast protection by way of the transverse beams and an interlaid series of connected trays, as described further herein, and the layer of earth, sand or other aggregate provided thereon.

Referring to FIGS. 1 to 5, there is shown a protective shelter 1 in accordance with the invention comprising opposite outer supports, of which adjacent outer supports 2 and 3 are visible in FIG. 3. Roof structure 4 extends between the supports to provide a first layer covering the space between the outer supports. In the case of the illustrated embodiment the roof structure first layer is formed from a plurality of trays 5 supported on transverse beams 6 extending across the width of the shelter in a manner very much as described in our previous application PCT/GB2009/051431. In use of the shelter the trays will be filled with an aggregate material providing blast protection, but no such material is shown in the Figures.

The roof structure first layer provides a first level of protection to shelter, but a second level is provided by pre-detonation screen 7 which comprises a plurality of individual panels 8 arranged and supported over and spaced from the first layer and presenting a substantially closed surface to an incoming projectile. In the illustrated embodiment, panels 8 are made from plywood, which constitutes the first panel material. The panels are provided with edging elements 9, formed in this case from extruded aluminium and comprising opposed channels 10 and 11 into which the edges of neighbouring panels 9 are received as illustrated in FIGS. 3, 4 and 5.

Also shown in FIGS. 3, 4 and 5, but now also with reference to FIGS. 6 to 10 pre-detonation screen 7 is supported above the first layer of the roof structure by a plurality of rafters 12 extending from the first layer and by purlins 13, each purlin 13 comprising a plurality of individual purlin components 14 overlapping with and staggered with respect to each neighbouring purlin component, as is best shown in FIGS. 4 and 5, and connected together by connecting elements 15 to form a continuous but staggered purlins 13 supporting the pre-detonation screen.

As will be appreciated with reference to FIGS. 3 to 10 the connecting elements of this embodiment are arranged to be received within rafters 12 as illustrated, but many other suitable forms of connecting element may be envisaged.

Purlin components 14 are arranged with slots 16 to provide an interference fit with receiving channels 17 on the connecting elements but, again many other means may be envisaged to secure the purlin components into the connecting elements.

Referring now to FIGS. 3, 4 and 11 to 14, pre-detonation screen 7 is supported on the opposite outer supports with the aid of anchor beam 18, which is shown in construction in FIGS. 13 and 14. Anchor beam 18 comprises a first longitudinal beam element comprising a plurality of first (outer) anchor beam components 19 laid end to end and a second neighbouring longitudinal beam element side by side with the first element and comprising a plurality of second (inner) anchor beam components 20 arranged end to end, joints between individual anchor beam components of the first longitudinal element being staggered with respect to joints between individual anchor beam elements of the second longitudinal element.