10 Speci ication 65-^057 discloses a block with features which super icially are very similar to the block of the present invention but in fact is designed for completely different reasons. In that specification a block is disclosed having an offset face providing projecting

15 portions and corresponding rebates which are arranged to leave a narrow gap between adjacent edges of the blocks. These gaps are provided so that they can be filled with mortar or cement to ensure a firm structure. However, in that specification there is no recognition of the

20 problems of moulding a close tolerance block and thus, whilst the gaps will aid in seating the blocks one on another, the cooperating inner surfaces of the extending portions and rebates are not specifically contoured to accommodate tolerance variations-. Accordingly, if these

25 edges are not exactly moulded the blocks still may not seat and will, as described above, produce a weakened structure.

OMPI WIPO

-1-

"Improved Building Block and Structures formed therewith"

TECHNICAL FIELD

This invention relates to an improved form of inter¬ locking building block and to structures including such blocks.

BACKGROUND ART Interlocking blocks are known the closest prior art of which we are aware being exemplified by British Patent Specification Numbers 577052, 591067, 65*057 and 788652.

Specification 577052 illustrates a moulded block formed of three, vertical parallel and spaced layers, the intermediate layer projecting beyond the outer layers, at one end and at the top or bottom, and being inset at the other end and at the top or bottom so that adjacent blocks will interlock. However in that arrangement the block is complicated to mould and the location is provided by the same portions of the block as those which transmit the load.

Specification 591067 and 788652 both illustrate similar blocks to the present invention having an offset face but in both disclosures the projecting portions are intended to compliment the rebates. ^" Whilst such an

-3-

DISCLOSURE OF INVENTION An object of the present invention is to provide an improved form of interlocking building block which can be laid easily by unskilled labour, which wall seat securely and w-hich can produce readily reinforced structures.

According to the present invention a building ulock comprises an inner wall and a spaced, parallel outer wall, at least one web connection between the inner and outer walls, an offset face on said outer wall, said face being offset vertically to provide a projecting extension along the greater part of a horizontal edge of the outer wall, and a rebate along the greater part of the opposed horizontal edge of the outer wall whereby one block may interengage with adjacent blocks aboveand below, the offset face being so arranged, by the provision of the projecting extension being smaller in depth than the corresponding rebate and the projecting extension and the rebate each having a generally vertically extending inner wall one of which has a contoured surface portion facilitating inter- engagement of a projecting extension and a cooperating ^* rebate, that the offset face merely locates the block whereas load is transmitted through the inner and outer walIs. Preferably there is a contoured surface portion on the inner wall of both the projecting extension and the

-k-

inner edge of the rebate, suitably radiused edges.

Preferably the inner wall of the block includes a recess for ducting or an intersecting wall and in order tp accommodate a staggered relationship for blocks of adjacent layers the recess in the inner wall is formed at one end of the block in left-hand and right-hand arrangements and also centrally of the inner wall for a block above or below. The block may have a cavity defined between the inner and outer walls or may be trough-shaped.

The invention also includes a structure comprising a plurality of layers of interlocking building blocks in accordance with the invention assembled together.

The structure may also include horizontal, -diagonal and vertical reinforcing means„

Preferably the blocks are rectangular and have space inner and outer walls joined by a web connection at each end. Also preferably each block is provided with a projecting extension and rebate on both its inner and outer wall. If desired the inner and outer walls of rectangular blocks may have projecting extensions along two adjacent edges and rebates along the other two edges so that adjacent blocks inter-engage above and below and at the ends. BRIEF DESCRIPTION OF DRAWINGS -

A wall or a building built of blocks in accordance

-5-

with -the invention has the following advantages:- a) the inter-engaging ensures that blocks are correctly laid to give a vertical wall and may easily be laid by unskilled labour; b) the inter-engaging and reinforcing gives strength; c) the inter-engaging gaps entending through the wall; d) the blocks give a much greater versatility than was previouslj ^* - ^* known; and e) the arrangement of tiie cooperating extensions and rebates ensures proper seating for load transmission. The blocks may be assembled dry as they are or may be secured together in any commercial manner e.g. by mortar, cement, bitumen mastic or any other suitable material.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of a standard rectangular interlocking block in accordance with the invention;

Figure 2 is a plan view of figure 1; Figure 3 is a section on A - A of figure 2; Figure h. is a section on B .- B of figure 2; Figures 5a and 5b are a perspective view and a plan view respectively of an interlocking corner block in accordance with the invention;

Figures 6a and 6b are left and right hand connection blocks in accordance with the invention;

Figure 7 is a connection block in accordance with the invention for fitting above or below left and right hand connection blocks shown in Figures 6a and 6b;

Figure 8 is a perspective view of an interlocking rounded block;

Figure 9 show ^r s in perspective the interlocking connection blocks of figures 6a, 6b and 7 in accordance with the invention;

Figure 10 shows in side elevation diagonal and vertical reinforcements of a wall made of rectangular interlocking blocks; Figure 11 is an end view of a retainer for diagonal and horizontal reinforcing rods;

Figure 12 is a perspective view of the retainer shown in Figure 11;

Figure 13 illustrates pier link reinforcing; Figure 1 is a perspective view of lateral reinforcement;

Figure 15 is a cross-sectional plan view of a reinforced pier or duct formation incorporating connection blocks as shown in figure 6a and 6b; Figure 16 is a cross-sectional plan view of an adjacent layer of the pier or duct formation shown

OMP _< A. 1P

in figure 15 incorporating a different form of interlocking connection block, shown in Figure 7 and without reinforcement;

Figure 17 is a cross-sectional plan view of a layer 5 of a column including reinforcement; and

Figure 18 is a cross-sectional plan view of an adjacent layer to the layer of the column shown in figure 17 and without reinforcement.

BEST MODE OF CARRYING OUT THE INVENTION 10 In the drawings, particularly figures 1 to 4, a building block 1 has an inner wall 2 and an outer wall 3. Both the inner wall 2 and the outer wall 3 has formed integral therewith an offset face and 5 respectively. The faces 4 and 5 are of slightly smaller dimensions ^• - 15 than their respective walls 2 and 3 to allow for slight tolerance variation during manufacture and to help ensure that the load bearing walls 2 and 3 are in engagement with adjacent blocks above and below. The faces 4 and 5 are offset in such a way that each face projects beyond 20 one end to form a projecting extension 6 along the greater part of the edge of the respective wall; similarly because the faces project beyond one end each face is inset at the opposed end to form a corresponding rebate 7« In addition, and as shown in Figure 1 the 25 faces 4 and 5 are offset not only laterally but also longitudinally so that adjacent blocks fit together above and below and at each end. In addition to the offset

OMPI _

faces being smaller than their associated walls so that the projecting extensions are slightly smaller in depth than the corresponding rebates, the horizontally extending rebates 7 and corresponding projecting extensions have specially contoured inner walls 5' and 6' which facilitate interengagement of the blocks and ensure that the blocks seat properly so that the offset faces only locate. As shown these contoured inner walls are radiused but alternatively the w ^r alls may be tapered as disclosed in connection with later described embodiments.

The inner and outer walls 2 and 3 are joined together at each end by a web connection 8 so as to define a cavity 9 between the walls. The block 1 is also provided with channels 10, within the cavity_9, for receiving a retainer plate for isolating a vertical column for reinforcements by concrete. Capillary channels 11, along the end joints to allo -the escape of water in the event that water leeks into the cavity 9 or the end joints when blocks are assembled together. Figures 5 and 5b illustrate a corner block 12 having an inner wall 13 and an outer wall 14. Each wall has a face 15 offset so as to provide extensions and rebates as with the standard block of figures 1 to 4.

However, in these figures the walls 13 and 14 are joined together by webs 15 of a different form which join

the walls 13 and 14 together only at the bottom. Three

webs 15 are provided for a corner block so that an opening 16 may be defined by two adjacent webs 15 through w ^r hich a reinforcing rod (not shown) may pass in assembly of a building. The projecting extensions and corresponding rebates are specially designed as disclosed in connection with figures 1 to 4.

Figures 6a and 6b respectively show left and right hand connection blocks described in more detail with reference to figure 9. Figure 7 shows the third block of the set of three connection blocks for fitting above and below the blocks shown in figures 6a and 6b in order to allow the blocks to be laid staggered. This block may also be used in isolation as a joist support. The blocks of these embodiments, as with the previous embodiments, also have offset faces in which the projecting extensions are of slightly smaller depth than the corresponding rebates. However, as described below, the inner walls of the horizontally extending rebates and the corresponding projecting extensions are tapered. Moreover, the vertically extending rebates and corresponding rebates are also tapered to facilitate interlocking and to ensure that the walls of one block abut the walls of an adjacent block to prevent the creation of gaps between blocks. Although substantially rectangular blocks are preferred other blocks incorporating the same principle may be used.

For example, figure 8 illustrated an alternative form of block 19 which is curved but has similar offset 'faces 20 on its inner and outer w ^τ alls 21 and 22 and fits together in a similar manner. In use blocks are fitted together one above the other and end to end so that the faces 5 of the outer wal 3 of each block fi together with the faces 5 of adjacent blocks and similarly the faces 4 of the inner wall 2 of each block fit together with the faces 5 of adjacent blocks. In this way the blocks are located against lateral displacement and the gaps between adjace blocks are covered.

Figure 9 illustrates the use of the set of connectio blocks 31 shown in figures 6a, 6b and 7 together with an alternative embodiment of standard block. On the upper layer the blocks 3i have an inner wall 32 and an outer wall 33. The inner wall 32 and the outer wall 33 have formed integral therewith an offset face 34 and 35 respectively. The face 35 is of slightly smaller dimensions than the wall 33 but is offset in such a way that the face projects beyond one end to form a projectin extension 36 along the greater part of the e.dge of the wall 33. The face 34 is of slightly smaller dimensions than the wall 32 in the left-hand block 37 and shorter and of smaller dimensions than .the wall 32 in the right- hand block 38 so as to form a projection 39 on the left- hand block 37 and a rebate on the right-hand block 40.

O P

Sirailarly because the face 35 projects ^" beyond one end of the outer wall 33 the face is inset at the opposed end to form a corresponding rebate 41. In addition, as shown clearly from figure 9, the faces 3* and 35 are offset not only laterally but longitudinally so that adjacent blocks fit together above and below and at each end ₀

One end of each type of the connection blocks 37, 38 is similar in design to the standard rectangular block shown in figure 1 whereas the other end is specially contoured to provide a recess 42 to form a housing for intersecting walls, ducts or pier links. The contoured end of the connection blocks is formed by the inner wall 32 being formed shorter than the other wall 33 and the interconnecting web 43 at that end. being disposed slightly inwardly of the position shown in a standard rectangular block. Figure 15 of the drawings illustrates the same type ^" of connection blocks used for a pier formation.. The recessed portions are provided with a small rebate 44 to allow a panel to be fitted flush to enclose service ducting and the like.

In order to ensure that the blocks are seated properly the offset faces 34 and 35, as explained above, are designed so that the projecting extensions are slightly smaller in depth than the corresponding rebates so that small gaps 45 are present between adjacent faces„ Also, in order to further facilitate seating of the blocks

0MP1 wipo ^" , y

the inner walls of the projecting extensions and corresponding rebates are tapered. Moreover, to the left in figure 9, an alternative form of standard block 46 is shown which includes similar tapered portions rather than the radiused edges of the embodiment of figures 1 to 4.

Figure 16 illustrates more clearly the use of the connection block 50 for pier or duct formation in which the inner and outer walls 51 and 5 are interconnected by webs 53 and the outer wall 52 has an offset face 54. However this inner wall 51, instead of being inset from one end, is formed in two parts so as to form a duct or pier connection recess 55. Each part of the inner wall 51 has an integral face portion 56 offset to provide a projection 57 or a rebate 58 and is also offset ^{• *} longitudinally. This type of connection block is positioned above and below left and right-hand connection blocks as shown in perspective in figure 9 in the lower layer. Depending upon the load to be encountered by a structure constructed o interlocking blocks a certain degree of reinforcement is necessary. The recess 55 is positioned offset relative to the inner and outer walls of the block but substantially centrally relative to the offset faces of the block as clearlj ^* - seen in figure 16. Structuresmade with blocks -in accordance with the invention preferably include diagonal and vertical

reinforcement in a wall and horizontal reinforcement at a ring beair.

Figure 10 illustrates in side elevation a wall made up of rectangular interlocking blocks which may be of

\ the standard type shown in figures 1 or 9 together with connection blocks of the types shown in figures 9 and

15 or 16.

The blocks of one layer are offset by half with respect to blocks of the layer above or below ^r in standard fashion but because the inner and outer walls define a cavity diagonal and vertical reinforcing rods 60 can be arranged as shown secured to a hook mounted secured in the foundations.

The reinforcing rods 60 in a non-permanent structure where no concrete reinforcement is possible preferably each have a rectangular nut 61 on their lower end so that they can be tw ^τ ist-fitted into engagement with an elongate metal anchor strip 62. The anchor strip 62 having - rectangular slots 63 corresponding to the nuts 61. As an alternative the rod 60 can be replaced by a flexible wire rope for example. Figure 13 clearly indicates the taper of inner walls of the rebates and projecting extensions and also the greater depth of the rebates leaving a slight gap when the blocks are assembled. Figure 14 illustrates lintel blocks 70 which may be used for internal reinforcement at any desired position.

O PI

Λ. IPO «

The lintel course is used to form a matrix for fixing blocks and also a ring beam as well as lintels themselves In this figure the lintel blocks 70 are being used as a ring beam between floors of a building or for supporting roofing. The lintel blocks 70 have similar wall structures to the rectangular blocks of figure 1, e.g. inner and outer walls 71 and 72 with offset faces 73 and 74 respectively, however instead of being inter-connected by end w"ebs the walls 71 and 72 are connected by a bottom web 75 which forms the block into a trough w ^τ hich receives horizontal reinforcing rods 7 set in concrete and also receives wooden fixing blocks 77 to which timber plate 78 can be secured for the flooring or for roof trusses. The lintels can also form a base for holding down bolts 79 used for subsequent floors as an additional tie. As clearly shown the special design of cooperating extension and rebates is as disclosed with reference to the previou embodiments.

Figures 15 and 16 referred to above also incorporate lintel blocks 70 for horizontal reinforcing tie rods 80 which have curved ends 81 for cooperating with vertical reinforcing tie rods 82. These reinforced concrete links can be positioned at any desired vertical height. These figures also illustrate the use of connection quoin blocks 83 which are of linked type.

Quoin blocks 83 are also used in the formation of

OMPi ι' WWΪIPPOO

columns as shown in figures 17 and 18 except that the webs 84 of the blocks are provided with an aperture 85 for all vertical connections to be made. The columns can be used as shuttering or permanent shuttering can be reinforced, The size _, of the columns and the reinforcement can be varied according to the load. Figure 17 for example, show's vertical reinforcement rods 86 set within a bed of concrete in the internal cavity defined by the blocks. In addition lateral reinforcement is provided by lintel-type quoin blocks and a horizontal reinforcing rod 87 which has curved ends 86 and which is wound about vertical comet reinforcement rods 89.

Preferably, although not shown, the outer surface of a block is treated so that it is weatherproof it may also be pro-vided with some simulated finish, e.g. conventional brick or pebble-dash. Also, if desired, the whole structure may be rendered to close the gaps between adjacent blocks.

Although only some forms of blocks have been illustrated and described half-blucks may also be provided in accordance with the invention in order that a complete building may be made. In the blocks of the present invention the inner and outer walls are the load- bearing portions and the offset _. faces merely cover the joins between blocks and provid-e the interlocking location.