GB2521759A - A blank for forming a construction block - Google Patents

Abstract

A blank 1 for forming a construction block that interconnects with other construction blocks to form a structure. The blank comprises a planar sheet of material with fold lines 18, 19, 21, 22 defining four primary panels 3, 4 and a secondary panel, the sheet being foldable so that free edges 5 of the primary panels move into abutting relation to form the outer walls of a block with an internal cavity which the secondary panel extends into. There may be a slot in the centre of the secondary panel and fold lines 21, 22 may extend towards it. Connecting tabs 8 may extend from the primary panels. Each primary panel may have a recess 14 to receive a connecting tab of an adjacent block. A block formed from such a blank may have at least two translucent or transparent sides.

Description

A Blank for Forming a Construction Block The present invention relates to a blank for forming a construction block and to a block formed from the blank of the invention.

Scenarios exist where it is necessary to quickly and easily construct a temporary or semi permanent structure; examples of such structures may include a disaster relief shelter, a flood defence or a sangar.

jo Most conventional building techniques require a skilled individual to assemble a block based structure, wherein a binding agent, such as cement or mortar, is normally required to combine the blocks. The binding agent takes time to set, and this usually delays the completion of the structure. Furthermore, the skilled labour required to assemble conventional construction blocks is not always available when a temporary or semi permanent structure is required, this is especially true in disaster relief scenarios.

Tt is therefore desirable to provide a blank for forming a construction block, and a block formed from the blank, that is suitable for use in a range of scenarios where the speed and or the ease of construction are of high importance. It is also desirable to provide a relatively lightweight blank and block that is easily transported and assembled.

The present invention seeks to provide a blank for a construction block and to a construction block formed from the blank of the invention that is designed to enable an unskilled person to quickly and easily assemble a temporary or semi permanent structure.

According to embodiments of the present invention there is provided a blank for forming a construction block that interconnects with other construction blocks to form a structurc such as a wall, the blank comprising a planar shcct of matcrial having fold lines to define four primary panels and a secondary panel, the sheet being foldable so that free edges of said primary panels move into abutting relation to form the outer walls of a block that together define an internal cavity, the secondary panel being configured to fold so as to extend within said internal cavity.

Preferably, each primary panel extends in opposite directions from a respective edge of the secondary panel, the secondary panel being defined by a plurality of secondary pane' sections foldable relative to each other, said sections being configured to fold, after each primary pane' has initially been folded out of the pbne of the secondary panel, to cause said free edges of said primary panels to move into abutting relation.

Preferably, said secondary panel sections comprise main panel sections from each of which a primary panel extends and, joining panel sections that extend between said main panel sections, said joining panel sections and main panel sections being separated by a first fold-line along a main panel section edge.

o Preferably, each joining panel section comprises a pair ofjoining panel section halves separated by a second fold-line, each joining panel section half being configured to fold about its first and second fold-lines into overlapping relation to cause said main panel section edges to meet and the free edges of the primary panels to be drawn into abutting relation.

Advantageously, the b'ank comprises a slot formed in the centre of the secondary panel and said first and second fold lines extend towards and terminate at said s'ot.

Advantageously, the fold line between each primary panel and its corresponding main panel section is configured so that, when a primary panel folds relative to said main panel section, a connecting tab formed from the main panel section extends out of said main panel section and remains in the plane of the primary panel.

Preferably, each primary panel defines a recess configured to receive a connecting tab extending from a primary panel of an adjacent block.

In an alternative embodiment there is provided a base panel, each primary panel extending in opposite directions from a respective edge of the base panel, the secondary pancl bcing dcfincd by a first and a sccond secondary pancl scction each of which extend from an edge of a primary panel remote from said base panel, the secondary panel sections being configured to fold relative to said primary panel about said edge, after said primary panels have been folded relative to said base so that said free edges of said primary panels abut, into said internal cavity so that each of the secondary panels extend at an angle towards each other and each secondary panel extends between said edge of a primary panel and the base panel.

Preferably, each secondary panel has a main panel section and secondary panel support panel sections configured to fold relative to said secondary panel section prior to folding said secondary panels into said internal cavity so that each secondary panel support pand section will lie against an inside surface of a primary panel.

Advantageously, the edges of each secondary panel section that extend to the base are spaced from each other and a slot is formed in the base between said edges.

Advantageously, the blank comprises a connecting tab extending from an edge of each jo primary panel.

Preferably, the connecting tab extending from the edge of the primary panel from which the secondary panel sections extend is formed from said secondary panel section and is configured to fold out of said secondary panel and remain in the plane of the primary panel.

Preferably, each primary panel defines a recess configured to receive a connecting tab extending from a primary panel of an adjacent block.

According to the invention there is provided, a construction block folded from a blank according to any preceding claim.

According to the invention there is provided, a block and system for building shelter structures, said block folded from a substantially monoplanar shape into a three dimensional block that has at least four sides surrounding a central cavity, wherein at least one side includes an attachment tab.

Advantageously, at least one tab attaches the block to another block.

Preferably, at least one tab acts to secure the folded block sides.

Preferably, at least some of the tab is resiliently deformable.

Advantageously, the block contains at least two transparent or translucent sides.

According to the invention there is provided, a system utilising blocks according to any preceding claim.

According to the invention there is provided, a system using a plurality of blocks according to any preceding claim, a roof element, and at least one connector between the roof element and blocks.

According to the invention there is provided, a method of constructing a shelter according to any preceding claim.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure lisa parallel projection view of the blank of the first embodiment of the present invention; Figure 2 is paraflel projection view of the block assemb'ed from the blank of Figure 1; Figure 3 is a side elevation view of the block shown in Figure 2; Figure 4 is a top view of the block shown in Figure 2; Figure 5 is a bottom view of the block shown in Figure 2; Figure 6 is an end view of the block shown in Figure 2; Figure 7A is a parallel projection view of the window attachment; Figure 7B is a parallel projection view of the half sized block; Figure 7C is a parallel projection view of the door attachment; FigureS is a parallel projection view of the completed shelter; Figure 9 is an exploded parallel projection view of the completed shelter; Figure mA is a parallel projection view of the roof clip; Figure loB is a parallel projection view of the roof strut; Figure bC is a parallel projection view of the corrugated roof sheet; Figure 11 is a top view of the blank of the second embodiment of the present invention; Figure 12 is a parailcl projection vicw of thc block asscmblcd from the blank of Figure 11; Figure 13 is a side elevation view of the block shown in Figure 12; Figure 14 is a top view of the block shown in Figure 12; Figure 15 is a bottom view of the block shown in Figure 12; Figure 16 is an end view of the block shown in Figure 12; A blank 1 suitable for folding into a block 2 is shown in Figure 1. The blank 1, when folded, provides a block 2 that can be attached to another block 2 of the same description when both blocks 2 are suitably arranged.

An assembled block 2 is shown in Figure 2. With reference to Figures 1 and 2, it can be seen that the block has four vertical, predominantly flat panels, two large panels 3 and two small panels 4, the large panels being the same height as the small panels, but greater in width. The panels are arranged so that like sized panels form opposite sides of a four sided outer wall, the vertical edges of the panels being in perpendicular o abutting relation such that the outer wall is rectangular in top view. The outer wall forming panels are herein collectively referred to as the primary panels. The top planar face 6 of the block 2 is defined by the upper edges of the primary panels and the bottom planar face 7 by the lower edges of the primary panels. The small panels can be said to form the end walls of the block.

The block 2 has four tabs 8 designed to connect by click-fit to corresponding cut outs 9 on another block 2 of the same description. The tabs 8 are located on the primary panels, extending vertically upwards off of the upper edges; each large panel 3 has two tabs 8 and each small panel 4 has one. At the end of the tab 8 is a tab hook 10. The tab hook lois a small protrusion on the inner face of the tab 8 with, as shown in Figure 3, a rounded side ii and a flat side 12, the rounded side ii being upper most and the flat side 12 facing down toward the block 2.

The cut outs 9 are located on the lower edges of the primary panels; each large panel 3 has two cut outs 9 and each small panel 4 has one. The cut out 9 comprises a recess 13 and an attachment slot 14, the recess 13 being an indentation in the outer face of the primary panel, while the attachment slot 14 is located at the end of the indentation and extends entirely through the panel. The cut outs are profiled to receive a tab 8, such that thc cdgcs of thc rcccss 13 and the pcrimctcr of the tab 8 abut to provide alignment; the hook 10 sits in the space created by the attachment slot 14.

Tn a wan two or more blocks 2 are p'aced end to end to form a row. In a row the smafi panels 4 of adjacent blocks 2 are aligned and abut; one or more bthcks 2 may then be placed on top so that the bottom planar face 7 of the uppermost block abuts the top planar face 6 of the block 2 below. Each uppermost block 2 is aligned with the large panel 3 faces flush to the large panel 3 faces of the block 2 below; the small panel 4 faces are offset to lie halfway between the smafl panel 4 faces of the block below so that the uppermost block 2 half covers each of the two blocks 2 immediately below it.

Tt shall be appreciated that the blocks 2 can be further configured to form a wall corner structure, the wall corner structure being the meeting point of two perpendicular walls.

In a wall corner structure, an appropriately arranged block 2 may be placed on top of another block 250 that the large panels 3 of the uppermost block 2 are disposed at a right angle to the large panels 3 of the block 2 below, with one of the small panels 4 of the uppermost block being flush with a large panel 3 of the block below, such that the jo blocks are in overlapping relation, and a large panel 3 of the uppermost block being flush with a small panel 4 of the block below, such that the corners of each block 2, formed of said panels, are aligned.

The cut outs 9 located on the lower edge of the primary panels are spaced so as to engage with the tabs 8 located on the upper edge of the primary panels when two or more blocks are assembled to form a wall or a wall corner structure.

%srhen two or more blocks 2 are assembled, the combination of a tab 8 and a cut out 9 causes the blocks 2 to align and holds them together. In order for combination to occur, an appropriately aligned block 2 is pushed down on top of another, such that the tab 8 deflects to allow the tab hook 10 to pass over the indented surface of the cut out 9; this deflection is facilitated by the rounded upper edge ii of the hook 10 which acts to push the tab 8 outward when vertical load is applied. When the hook 10 passes over the slot 14 it clicks into position and is prevented from coming apart again by interference of the flat surface 12 of the hook 10 and the corresponding edge of the slot 14. In this way, the blocks 2 can be built into a wall that requires no additional construction materials or binding agents; this facilitates the fast and easy assembly of the wall by a person with no prior construction experience.

The block 2 has an internal structure which is designed to provide another attachment point when assembling a wafl. Tn a row, the smafi pands 4 of adjacent blocks 2 are aligned and abut so that the tabs 8 associated with these faces also align and abut, with the tab hooks 11 on the non abutting faces. Said internal structure attachment point provides a slot 15 through which these abutting tabs 8 pass when a block 2 is placed upon two blocks 2 in the row below. The slot 15 is sized so that the tab 8 outer edges locate against a corresponding edge of the slot 15 to provide additional alignment.

The internal structure comprises four trapezoidal panels, two large trapezoidal panels 16 and two small trapezoidal panels i; each trapezoid has unequal length paraflel edges and equal length non parallel edges. The large trapezoidal panels 16 are connected to the upper edges of the large primary panels 3 by the long paraflel edges of the large trapezoids 16. Likewise, the small trapezoidal panels 17 are connected to the upper edges of the small primary panels 4 by the long parallel edges of the small trapezoids 17. The non parallel edges of each trapezoid abut the non parallel edges of the two adjacent trapezoids to form a trapezoidal prism with open parallel faces, the Jo larger of these faces being coincident with the top planar face 6 of the block 2. Each trapezoidal panel is angled in toward the centre of the block 2S0 that the smafler of the two open parallel trapezoidal prism faces is coincident with the bottom planar face 7 of the block; this open face forms the aforementioned slot 15.

The blank 1, Figure 1, is the block 2 in unfolded form and is predominantly flat so that multiple blanks 1 can be stacked while taking up the minimum possible height. Tn this way, the blank 1 is more space efficient than the block 2 giving it the advantage that it is easier and cheaper to transport or store.

The blank 1 is formed of a planar sheet of material that is divided up into the panels by fold lines. The primary panels are arranged around a central, secondary panel. The primary panels comprise the two large panels 3 and the two small panels 4 that are configured to fold into abutting relation to form the outer wall of the block. The secondary panel comprises the four trapezoidal panels, the two large trapezoidal panels i6 and the two small trapezoidal panels 17 that are configured to fold to form the trapezoidal prism of the internal structure. The secondary panel further comprises four pairs oftriangularjoining panels.

Hcrcinaftcr, thc trapezoidal pancls arc referred to as main panel sections, and the triangularjoining panels 20 referred to as joining panel sections, to elarifythat both panels form sections of the secondary panel. The main panel sections are distinguishable as large main panel sections 16 and smafi main panel sections l7to refer to the large trapezoidal panels 16 and small trapezoidal panels 17 respectively.

The main panel sections are arranged so that their respective short parallel edges form a rectangular opening in the centre of the blank, with like size main panel sections forming opposite edges of said opening. The long parallel edge of each main panel section forms one of four sides to the secondary panel along which a primary panel is attached by a fold line.

When the main panel sections are folded to form the internal structure, the rectangular opening is disposed to provide the slot 15 through which tabs 8 pass when a block 2 is placed upon the two blocks 2 in the row below.

The joining panel section pairs are arranged between the main panel sections, with o each joining panel section pair contiguous with two adjacent main panel sections a'ong first fold lines 21; there also being a second fold Une 22 disposed between each joining panel 20, such that the first and second fold lines of each joining panel pair extend in toward the centre of the secondary panel, converging at a respective corner of the rectangular slot.

Each small primary panel 4 is connected along the long parallel edge of a smafl main panel section 17 by a small panel fold line 18. Likewise, each arge primary panel 3 is connected along the long parallel edge of a large main panel section 16 by a large panel fold line 19.

The fold lines between the primary panels and the main panel sections are broken where the tabs 8 are attached to their respective panel, the tabs nesting in cut outs 23 in the main panel sections, so that when a primary panel folds relative to main panel section, the tab is erected out of a main panel section and remains in the plane of the primary panei. The cut outs 23 in the main panel sections allow the tabs 8 to lie in plane with the blank 1. The tab 8 may be partially reduced in thickness at the hook 10 so that the hook 10 can project from the tab's body, and subsequently interface with the attachment slot 14, without sifting proud of the blank 1. This has the advantage of allowing casy stacking of thc blanks 1.

To assemble the blank 1 into a block 2 the large primary panels 3 are folded about the large panel fold line 19 to a position perpendicular to the blank i; the arge primary panels are folded in direction Y so that the associated cut outs 9 face outward. The small primary panels 4 are folded about the small panel fold line 18 to a position perpendicular to the blank 1; the panels are folded in direction X so that the associated cut outs 9 face outward. The main panel sections of the secondary panel must then be pulled upwards, in direction Z, to form the trapezoidal prism; the joining panel sections are caused to fold about their common fold line 22 as the non parallel edges of the main panel sections come together. When the prism is formed the joining panel section pairs abut. The action of forming the prism a'so draws together the primary panels so that they meet at the vertical edges 5.

The small panels 4 have a groove 24 in each vertical edge 5 designed to connect by interference fit with a tongue 25 on the corresponding vertical edges of the large panel 3. When the vertical edges 5 of the primary panels abut the tongues 25 sit within a jo corresponding groove 24. The tongue 25 and groove 24 connectors are sized so that that the inner edge of the tongue 25 interferes with the appropriate outer edge of the groove 24 to ensure that each panel is securely held in the vertical.

Starting the assembly process with the blank 1 oriented as shown in Figure 1 will result in the assembled block 2 being supported on the tabs 8; the block 2 must then be rotated so that the bottom planar face 7 is facing downwards in order to be in the configuration shown in Figure 2.

When in block 2 form the internal structure provides a cavity 26, defined by the inner faces of the trapezoidal panels, which can be filled with an aggregate material such as earth or insulating foam to give additional beneficial properties to the wall.

Alternatively, the cavity 26 may filled with a material such as mortar, cement and the like to more permanently set the blocks. A further and particular benefit of the internal structure is that it acts to increase the stiffness of the block sides so that they are more resilient to lateral deformation.

Should circumstances require it, the block 2 may be unfolded so as to re-form the blank 1. This process requires the user to first remove the block 2 from the wall by detaching thc tabs 8 from thc cut outs 9. Each tab 8 must bc bcnt away of thc associatcd primary panel so the tab hook 10 is clear of the cut out 9; when all four tabs 8 have been rdeased the block 2 can be lifted away. To unfold the block 2 the tongue 25 and groove 24 connectors can be pulled apart so that the primary panels and interna' structure are free to fold flat.

In one possible embodiment of the invention, the block 2 can be made from plastic or a recycled plastic polymer. In another embodiment, the block 2 may be formed of -10-woodpulp and polyester fibre, it being water-repellent, extra low lint, of high tensile strength, antibacterial, and with predictable surface and structural evenness.

Alternative materials may be suitable; materials with properties of water resistance, mildew resistance and high tensile strength are preferable.

In an alternative embodiment, the block 2 can be made from a transparent or translucent material. This would allow natural light to pass into a shelter without the requirement for conventional windows.

Tt is envisaged that prefabricated shelter building components such as doors 27 and windows 28 woukl be provided alongside the blanks for construction of a complete shelter (Figure 8). The window 27 (Figure 7A) and the door 28 (Figure 7C) use the same tab 8 and cut out 9 system as the blocks 2 so that they may be securely aligned and fastened into a wall. A half sized block is also provided (Figure 7B) to provide greater building versatility.

A roofing system may be provided that connects to the exposed tabs at the top of a wall.

The envisaged system comprises struts 29 (Figure loB) and corrugated sheet 30 (Figure mc), wherein the struts 29 are long straight tubular extrusions laid horizontally; the corrugated sheet 30 aligns with the struts 29 so that the struts 29 lie in a corrugation. tn one possible configuration, the struts 29 would abridge two walls and attach by click fit mechanism to the tabs 8. Alternatively, the tabs 8 may comprise a disc shaped attachment slot that the strut 29 can be passed through; configured this way, struts 29 would be passed through aligning tabs 8 so as to abridge two walls.

Figure mA shows a clip 31 suitable for fixing the corrugated sheet 30 to the strut 29.

In a further embodiment of the invention the blank is modified so as to be suitable for manufacture from a corrugated sheet material such as Correx, cardboard or similar.

Materials of this dcscription can only bc folded in a direction paralici or perpendicular to the corrugations. The oblique fo'd B nes inherent to the b'ank of Figure 1 make it unsuitable for use with such materials.

Figure ii shows the modified blank 32. Figure 12 shows the block 52 as assembled from the modified blank 32. As before, the blank 32 is predominantly flat so that multiple blanks 1 can be stacked while taking up the minimum possible height.

-11 -The blank 32 comprises a planar sheet of material having fold lines that define panels, wherein the panels are configured to fold to form the construction block. Central to the blank is a rectangu'ar base panel 33, the base panel 33 is bordered on each side by a primary panel, with each primary panel being attached to the base panel a'ong a fdld line. The primary panels are made up of two small panels 34 and two large panels 35 that border the base panel 33 along small panel fold lines 36 and large panel fold lines respectively 37, wherein the small panel fold lines 36 are disposed on opposite short edges of the rectangular base panel 33 and the large panel 37 fold lines are disposed on opposite long edges of said panel 33.

The large primary panels 35 are rectangular in shape and are each bordered by two locking panels 38 disposed at opposite short edges and connected thereto by locking panel fold lines 39. Each large primary panel 35 also comprises two tabs 40 disposed on the edge opposite and parallel to the large panel fold line 37.

Advantageously, each tab 40 is equal in thickness to the blank panels and lie in plane with said panels such that they are flush with the planar face of the blank 32, thus the tabs 40 do not impede the stacking of multiple blanks 32. The tabs 43 are profiled to comprise a stem 53 and a head 54, the stem 53 being connected at one distal end to a panel and at the other distal end to the head The head 54 is profiled to have a tapered upper end, such that the top of the head 54 is narrower than the head's widest point, and a straight edged lower end where the head 54 meets the stem 53, arranged so that straight edges extend perpendicular from either side of the stem 53, the head being wider than the stem 53 by the combined length of the straight edges, and the head 54 being spaced away from the edge of the panel on which the tab is disposed by the length of the stem 53.

Each small primary panel 34 is bordered by a secondary panel 41 disposed on the oppositc cdgc to thc small pancl fold linc 36 and connccted thcrcto by a sccondaiy panel fold line 42. Each small primary panel also comprises a tab 43 disposed on the same edge as the secondary panel 41. The smafl primary panel tabs 43 are formed from said secondary panel sections, such that they are configured to fold out of said secondary panels 41 and remain in the plane of the primary panels when the blank is assembled into the construction block 52.

-12 -The locking panels 38 each comprise a cut out formed in the panel and open at the edge adjacent to the small primaiy panel. When the blank is folded into block 52 form, the cut outs are configured to receive a tab from a block 52 below when the blocks 52 are stacked.

Each secondary panel 41 is bordered by two secondary support panels 44. The secondary support panels 44 are disposed on opposing edges of the secondary panel 41, perpendicular to the secondary panel fold line 42, and connected thereto by a secondary support panel fold line 45. Each secondary support panel 44 is only bordered Jo by an secondary panel 41 such that the two other edges of the secondary support panel 44 are delimiting to the blank 32, wherein these delimiting edges can be distinguished as a distal delimiting edge 46 and a proximate delimiting edge such that distal delimiting edge 46 is furthest from the secondary panel fold line 42. Said distal edge 46 comprises a tab 47 that acts to locate the secondary support panel 44 upon assembly, and further comprises a cut out 48, open at said edge 46, and profiled so as to receive one of the large primary panel tabs 40 when the blank 32 is assembled to form a block 52 and the block 52 is placed upon another appropriately arranged block 52 of the same

description.

Two rectangular cut outs 51 are formed in the base panel to receive the secondary support panel tabs 47 when the blank is folded into a block.

To fold the blank 32 into a block, the large primary panels 35 are folded out of the plane of the page, so that they are folded about the large panel fold line 37 into a position perpendicular to the base panel 33. The locking panels 38 are folded perpendicular to, and in toward, the base panel 33 to form double layered end walls. The small primary panels 34 are then folded out of the plane of the page, so that they are folded about the small primary panel fold line 36 to be perpendicular to the base panel 33, and to abut thcir rcspcctivc cnd walls to form a third laycr in said wall.

The secondary panels 41 are folded in toward the base panel 33 with the secondary support panels 44 folded perpendicular thereto so that they may lie up against the inside face of the large primary panels 35. In final assembled form, the secondary panels 41 extend at an oblique angle to the small primary panel 34 so that their distal edge meets the upper face of the base panel 33 at the centre line C. -13 -The internal structure formed by the secondary panels 41 and secondary support panels 44 give support to the primary panels that form the walls of the block.

A further advantage of the internal structure is that it provides a cavity which can be filled with earth or insulating foam to give additional beneficial properties to the block.

Alternatively, the block 52 may be filled with an aggregate material such as mortar, cement and the like to more permanently set the blocks 52 when combined to form a wall.

jo The assembled block 52is shown in Figure 12. The top planar face of the block 52 is defined by the upper edges of the primary panels.

In a wall two or more blocks 52 are placed end to end to form a row. In a row the small primary panels 34 of adjacent blocks 52 are aligned and abut; one or more blocks 52 may then be placed on top so that the bottom face of the base panel 33 of the uppermost block 52 abuts the top planar face of the block 52 below. Each uppermost block 52 is aUgned with the large primary panel 35 faces flush to the large primary panel 35 faces of the block 52 below; the small primary panel 34 faces are offset to lie halfway between the small primary panel 34 faces of the block 52 below so that the uppermost block 52 half covers each of the two blocks 52 immediately below it.

It shall be appreciated that the blocks 52 can be further configured to form a wall corner structure, the wall corner structure being the meeting point of two perpendicular walls. In a wall corner structure, an appropriately arranged block 52 may be placed on top of another block 52 so that the large panels 35 of the uppermost block 52 are disposed at a right angle to the large panels 35 of the block 52 below, with one of the small panels 34 of the uppermost block being flush with a large panel 35 of the block below, such that the blocks 52 are in overlapping relation, and a large panel 35 of thc uppermost block bcing flush with a small panel 34 of the block below, such that the corners of each block 52, formed of said panels, are aligned.

The base panel 33 has a series of rectangular cut outs 49 formed therein. The cut outs 49 are spaced so as to receive the tabs 40/43 located on the upper edge of the primary panels when two or more blocks are assembled to form a wall or a wall corner structure.

When the blocks 52 are assembled, the combination of the tabs 40/43 and cut outs 49 causes the blocks 52 to align and holds them together.

In order for combination to occur, an appropriately aligned block 52 is placed upon another, such that a tab 40/43 is configured to pass through a corresponding cut out 49; the head 54 of the tab, at its widest point, is slightly wider than the cut out which it is configured to pass through. As vertical load is applied to the uppermost block, the tapered edge section of the head 54 of each tab 40/43 comes into contact with the outer edges of a corresponding cut out 49 so that the downward movement of the block 52 causes the head 54 of the tab to be compressed inwards. When the uppermost block 52 is in its final position, the head 54 of the tab is clear of the outer edges of the cut out 49 Jo so that the outer edges of the cut out are located between the head 54 of the tab 40/43 and the panel on which the tab is located. The deformed tabs 40/43 are somewhat restored in this final position so that the straight edge element of each tab may locate against the inside face of the base panel in which the cut out 49 is formed, so as to prevent the easy separation of the blocks.

The block 52 may be unfokled so as to re-form the blank 32. This process requires the user to first remove the block 52 from the wall by lifting the block 52 vertically upward; the tab 40/43 deforms so that the widest point of the tab 40/43 may clear the cut out.

The block 52 is then free to be moved away uninhibited. To unfold the block 52 the second aiy panel 41 and associated secondary support panels 44 must be lifted away from the base panel 33 to free the locking panels 38 so that the large primary panels 35 may also be laid fiat.

It shall be understood the prefabricated shelter building components shown in Figure 7 may be adapted by modification to the tab and cut out system so that they may be used with the alternative embodiment of the block 52 described above.

The roofing system shown in Figure 10 is suitable for use with little modification to the altcrnativc cmbodimcnt of thc block 52 dcscribcd abovc.

The invention has been described with reference to preferred embodiments only.

Modifications and alterations to the embodiments falling within the scope of the appended claims are included within the scope of protection.

Claims (12)

1. -15 -Claims 1. A blank for forming a construction block that interconnects with other construction bthcks to form a structure such as a wall, the blank comprising a planar sheet of material having fold lines to define four primary panels and a secondary panel, the sheet being foldable so that free edges of said primary panels move into abutting relation to form the outer walls of a block that together define an internal cavity, the secondary panel being configured to fold so as to extend within said internal cavity.
2. 2. A blank according to daim 1, wherein each primary panel extends in opposite directions from a respective edge of the secondary panel, the secondary panel being defined by a plurality of secondary panel sections foldable relative to each other, said sections being configured to fold, after each primary panel has initiafly been folded out of the plane of the secondary panel, to cause said free edges of said primary pane's to move into abutting relation.
3. 3. A blank according to claim 2, wherein said secondary panel sections comprise main panel sections from each of which a primary panel extends and, joining panel sections that extend between said main panel sections, said joining panel sections and main panel sections being separated by a first fold-line along a main panel section edge.
4. 4. A blank according to claim 3, wherein each joining panel section comprises a pair of joining panel section halves separated by a second fold-line, each joining panel section half being configured to fold about its first and second fold-lines into overlapping relation to cause said main panel section edges to meet and the free edges of the primary panels to be drawn into abutting relation.
5. 5. A blank according to daim 3, comprising a slot formed in the centre of the secondary panel and said first and second fold lines extend towards and terminate at said slot.
6. 6. A blank according to any preceding claim, wherein the fold line between each primary panel and its corresponding main panel section is configured so that, when a primary panel folds relative to said main panel section, a connecting tab formed from the main panel section extends out of said main panel section and remains in the plane of the primary paneL
7. 7. A blank according to daim 6, wherein each primary panel defines a recess configured to receive a connecting tab extending from a primary panel of an adjacent block.
8. 8. A blank according to claim 1, comprising a base panel, each primary panel extending in opposite directions from a respective edge of the base panel, the jo secondary panel being defined by a first and a second secondary panel section each of which extend from an edge of a primary pane' remote from said base panel, the secondary panel sections being configured to fold relative to said primary panel about said edge, after said primary pane's have been folded relative to said base so that said free edges of said primary panels abut, into said internal cavity so that each of the secondary panels extend at an angle towards each other and each secondary pane' extends between said edge of a primary panel and the base panel.
9. 9. A blank according to claim 8, wherein each secondary panel has a main panel section and secondary panel support panel sections configured to fold relative to said secondary panel section prior to folding said secondary panels into said internal cavity so that each secondary panel support panel section wifl lie against an inside surface of a primary panel.
10. 10. A blank according to claims 8 or 9, wherein the edges of each secondary panel section that extend to the base are spaced from each other and a slot is formed in the base between said edges.
11. ii. A blank according to claims 9 or 10, comprising a connccting tab extending from an edge of each primary panel.
12. 12. A blank according to daim ii, wherein the connecting tab extending from the edge of the primary panel from which the secondary panel sections extend is formed from said secondary panel section and is configured to fold out of said secondary panel and remain in the p'ane of the primary panel. -17-13. A blank according to claim 6, wherein each primary panel defines a recess configured to receive a connecting tab extending from a primary panel of an adjacent block.14. A construction block folded from a blank according to any preceding claim.15. A block and system for building shelter structures, said block folded from a substantially monoplanar shape into a three dimensional block that has at least four jo sides surrounding a centra' cavity, wherein at least one side includes an attachment tab.i6. A block according to claim 15, wherein at least one tab attaches the block to another block.17. A block according to claim 15 or 16, wherein at least one tab acts to secure the folded block sides.18. A block according to claim 16, 17, or 18, wherein at least some of the tab is resiliently deformable.19. A block according to a preceding claim having at least two transparent or translucent sides.20. A system utilising blocks according to any preceding claim.21. A system using a plurality of blocks according to any preceding claim, a roof element, and at least one connector between the roof element and blocks.22. A mcthod of constructing a shcltcr according to any preccding claim.