GB2111555A - Corrugated arched structures; e.g. explosion shelters or greenhouses - Google Patents

Abstract

The structure is formed from sheets of curved and corrugated material, of non-uniform curvature, meeting at the apex at a joint which may be rigid or pivotal. There may be end walls attached and the base is preferably mounted on a frame. As an explosion shelter, it may be buried, and the arch may be enveloped by a sheet of airtight and watertight plastics. As a greenhouse, the arch is transparent. <IMAGE>

Description

SPECIFICATION Arched shelters This invention relates to arched shelters for providing protection against a variety of situations.

In some applications the invention may be applied to a shelter for military of civilian purposes as protection against explosions, or nuclear contamination or fall-out. In other applications the invention may be applied to shelters for protection against the weather, for example in the form of a greenhouse, cloche, cold frame or as a temporary shelter for personnel, or a car or boat for example, or possibly for domestic or farm animals.

It is an object of the invention ro provide an improved shelter, which may be readily managed and transported to the site, can be quickly and easily erected, will be self-supporting and rigid when assembled, and will provide adequate protection for its selected purpose.

Broadly stated the invention consists in a protective structure comprising an arch formed of corrugated sheet material. According to a preferred feature the structure has two curved shells on opposite sides of the centreline, each shell having portions of different curvature. Each shell may be a unitary part or may be formed in two or more sections at different distances from the apex of the arch. In any case the two shells may be connected at the apex by a pivotal or hinged joint, for example the shells may have inter-engaging fingers or, alternatively, they may be rigidly connected by a sealing element.

In any case the shells are preferably so formed as to be structurally self-supporting, though in some cases the arch may be mounted on an internal framework, which also supports end walls.

In one aspect of the invention the arch is formed of metallic sheet material and is closed at one end and at least partly buried below ground level to act as an explosion shelter. Alternatively the arch may be of transparent or translucent sheet material and designed to act as a greenhouse, or cloche, or cold frame.

The invention may be performed in various ways and some embodiments with a number of possible modifications will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a sectional end elevation through a bomb shelter according to the invention positioned partly underground, Figure 2 is a sectional side elevation through the same bomb shelter, Figure 3 is a diagrammatic simplified end view illustrating another simple form of open air shelter according to the invention, Figure 4 is a side view of the shelter of Figure 3, Figures 5, 6 and 7 illustrate diagrammatically different curvatures which may be employed in the arched structure of the invention, Figure 8 is a diagrammatic perspective view illustrating a framed greenhouse according to the invention, Figures 9 and 10 illustrate alternative methods of attaching an end wall to such a greenhouse, Figure 11 is a diagrammatic end view on an enlarged scale illustrating one form of longitudinal shell joint, and Figure 12 is an end view on an enlarged scale illustrating a longitudinal rigid joint.

In the bomb shelter illustrated in Figures 1 and 2, the arch 10 is formed as two side shells joined at the apex 11 and each of corrugated sheet material, with a radius of curvature which reduces progressively towards the apex. Thus, the combined profile is approximately parabolic, though as will be explained different curvatures are possible and may be preferred for different applications. The arched shell so formed is located in a trench 12 dug in the ground and the lower extremities are positioned on a rectangular metal frame 13, which may be of angle or channel section. Before this frame is positioned in the trench a sheet of impermeable plastics 19 is laid in the trench and brought out over the lips of the trench, these side parts of the sheet being overlapped over the top of the arch, as shown at 14.Subsequently earth or loose packing material or sandbags are placed in position over the arch, as indicated at 1 5, and the end portions of the plastic sheet are preferably extended and brought out at the end of the trench, as illustrated at 1 6 in Figure 2. In conjunction with a dug-out depression 19, this provides facility for the occupants to leave the shelter when required and without admitting uncontrolled air from the atmosphere.

Alternatively the entrance may be blocked from inside by sandbags to include protection.

Necessary air for life-support may be provided by a combined fan and filter unit 1 7 connected to a duct 18, which leads through the doubled plastic sheet 1 6 to an external ventilator 20. If required, the covering material 1 5 may be covered by a further plastic or other membrane 21, which is in turn covered by yet another layer of rock or earth 22.

The bomb shelter so formed is extremely easy to manufacture, transport and erect and particularly if mechanical equipment is available for digging trenches such shelters can be completed in large numbers in minimum time.

Figures 3 and 4 illustrate a particular form of arched structure according to the invention standing in open air. The shelter is formed from two separate side shells 25, 26 each of corrugated sheet material and each having series of projecting fingers 27 along its top edge separated by slots 28. When placed together, as shown in Figure 3, the fingers and slot interengage and provide a strong through pivotal connection along the ridge and allow the base of the arch to be opened and closed to suit requirements. The structure thus formed may, for example, be fitted into trenches of different widths.

The corrugated sheet material may be of various different material. Corrugated sheet iron or steel, galvanised, painted, or rustproofed, are preferred materials for military or defence purposes. For other applications, particularly horticultural or agricultural, transparent or translucent arches may be preferred. Corrugated synthetic plastics materials can readily be shaped to the required curvature, for example they may be extruded of shaped under heat and pressure, or in the case of glass fibre reinforced plastics (G.R.P.) the composite material will normally be "laid up" on a shaped former. Other possible materials for different applications are asbestos cement and aluminium.

As mentioned the curvature of the arch may be varied to suit different applications. As shown in Figure 5 the arch is formed in two half shells joined at the apex 30, each shell consisting of a lower straight through corrugated portion 31 and an upper arcuate corrugated portion joined along a horizontal joint 33. In this case the upper curved parts 31 are of part cylindrical curvature centered on the axis 34 with a radius of curvature R. Thus each half shell has two different curvatures the radius of the lower section being infinite while that of the upper section is constant at R.In the arch illustrated in Figure 6, the curve of the arch 40 is parabolic and this same figure indicates possible alternative curves, as shown at 41 and 42 both of near elliptical form and in all cases the arch has a progressively varying curvature from top to bottom, but with a smaller radius near the apex 43. The different curvatures provide more or less internal volume with more or less headroom, while the narrower arch 41 may be preferable in a buried shelter for military or defence purposes.

Figure 7 illustrates another form of arch which in this case is of constant curvature throughout on an imaginary axis 45 located below the level of the bottom edge 46. This provides a shallower wider shelter with greater internal volume and has certain advantages in ease of manufacture. It may be formed in one continuous curve or there may be two shells joined at the ridge 47.

Figure 8 illustrates a greenhouse manufactured in accordance with the invention and including a simple internal frame intended primarily to support and provide attachments for the end walls.

The frame consists of two hoops 50, 51 one at each end, located on a rectangular base frame 52 anc! interconnected by a ridge bar 53 and two purlins 54. At one end there is a single upright bar 55 and at the other end a framework of uprights and horizontals forming a doorway 56, which is included to receive a hinged or sliding door. The shelter is completed by attaching corrugated transparent P.V.C. sheets over the main arch, the sheets being joined, if required, along the purlins 54 and the ridge 53, as shown in more detail in Figures 11 and 12. For this purpose each purlin 54 is made of Z-section, as shown in Figure 11, and the upper and lower corrugated sheets 57, 58 overlap against the two legs of the purlin and are connected by cross-bolts 59.At the ridge 53 there is a horizontai channel bar 60 onto which are fixed at intervals a series of clips 61, each having a double fold 62 which provides a slot below the channel to receive one of the corrugated sheels 63 and another slot in the opposite direction to receive the opposed corrugated sheets 64.

Figure 9 illustrates a method of attaching an end wall in position. The hoop frame 51 in this example is tubular and the end wall 70 is transparent plastic sheet, which is curled and partly wrapped over the tube 51 and fixed by a series of bolts or rivets 71. The main corrugated arched sheets 72 is also curled and wrapped partly around the tube overlapping the end panel 70 and fixed by a series of rivets 73, thus forming a firm substantially watertight joint.

Figure 10 illustrates a possible alternative fitting where the end panel 70 is secured by pins 76 in a series of clips 75 fastened to the corrugated arch panel 72.

Claims (13)

1. A protective structure comprising an arch formed of corrugated sheet material.

2. A protective structure according to claim 1, comprising two curved shells on opposite sides of the centreline, each shell having portions of different curvature.

3. A protective structure according to claim 2, in which each shell is a unitary part.

4. A protective structure according to claim 2, in which each shell is formed in two or more sections at different distances from the apex of the arch.

5. A protective structure according to any of Claims 2 to 4, in which the two shells are connected at the apex by a pivotal or hinged joint.

6. A protective structure according to claim 5, in which the shells have interengaging fingers.

7. A protective structure according to claim 5, in which the two shells are rigidly connected by a sealing element.

8. A protective structure according to any of the preceding claims 2 to 7, in which each shell is corrugated.

9. A protective structure according to any of the preceding claims, in which the shells are structurally self-supporting.

10. A protective structure according to any of the preceding claims, in which the arch is mounted on an internal framework, which also supports end walls.

11. A protective structure according to any of the preceding claims, in which the arch is formed of metallic sheet material and is closed at one end and at least partly buried below ground level to act as an explosion shelter.

12. A protective structure according to any of the preceding claims 1 to 10, in which the arch is of transparent or translucent sheet material and designed to act as a greenhouse, or cloche, or cold frame.

13. A protective structure substantially in any of the forms described herein with reference to the accompanying drawings.