This invention relates to a building block, in particular a building block which is self-levelling and self-aligning.

Many types of building blocks have been used in the past. These include basic rectangular bricks which are simply stacked and bonded with mortar. More complex building blocks have also been developed, including blocks with specific shapes which are supposed to allow for more accurate alignment of the blocks. Some of these blocks also rely on precise geometrical dimensions to position blocks relative top each other, which in theory works well but often in practice does not because of an inability to manufacture these blocks with the designed tolerances. This often leads to unstable structures and deterioration of structures.

In some instances the dimensions to which these blocks have been designed do not allow enough space for expansion and shrinking due to heat and cold, as an example. This may also lead to deterioration of a structure built from such blocks.

One example of a building block can be found in German Patent Publication No. 3810934, which provides a process for using residual concrete from ready-mix concrete. The process includes placing residual concrete in moulds to form concrete building blocks, the blocks having uniformly placed protrusions on one side and corresponding recesses on the opposite side to align adjacent blocks.

Another example can be found in French Patent Publication No. 2550568, which provides a block for constructing walls. The block has circular based truncated pyramid protrusions on one side and corresponding apertures on the opposite side.

A further example can be found in US Patent No. 3,394,517, which provides a building module, such as a building brick or block. The module has protrusions extending from its top face and recesses formed in its bottom face.

it is an object of the invention to provide a building block which at least partly overcomes the abovementioned problem,

According to a first aspect of the present invention, there is provided a generally parallelepiped-shaped building block for a wall, the block having six faces, including four side faces, an operatively upper face and an operatively lower face, two of the side faces are generally square in shape and comprise end faces of the block, and the remaining two side faces are generally rectangular in shape, the block having a plurality of male engaging formations in a single row, each male engaging formation comprising a protrusion in the shape of a pyramid having an equilateral polygon base with four sides and a flattened truncated end defined on a first side of the block and one or more complimentary shaped female engaging formations, each female engaging formation comprising an aperture defined on an opposed second side of the block, the engaging formations shaped and configured to permit at least a portion of each male engaging formation of a similar building block to be received within a female engaging formation, characterised in that each protrusion extends to a height above the upper face that is greater than the depth to which the aperture extends Into the lower face, so that a protrusion of one block is only partly receivable within an aperture of another block, to engage therewith, thereby providing for a predetermined gap to be defined between the upper face and the lower face of the engaged blocks respectively, and the truncated pyramids forming the protrusions and apertures have corners and the corners are flattened to edges.

Preferably, the engaging formations are defined on the upper and lower faces of the block.

Preferably, the male engaging formations are formed on and extend from the upper face and the female engaging formations are formed on and extend into the lower face of the block.

Preferably, the building block includes a pair of male engaging formations and a pair of female engaging formations.

Preferably, the, or each, protrusion extends to about 60 mm above the upper face of the building block and the aperture extends to about 50 mm in the lower face of the building block, operatively providing a gap of about 10 mm between the upper and lower faces of engaging building blocks which may be filled with mortar.

Preferably, the, or each, protrusion extends to about 40 mm above the upper face of the building block and the aperture extends to about 30 mm in the lower face of the building block, operatively providing a gap of about 10 mm between the upper and lower faces of engaging building blocks which may be filled with mortar.

Preferably, the building block has a height of about 75 mm.

According to a second aspect of the present invention, there is provided a wall constructed by means of building blocks as described above.

A preferred embodiment of the invention is described below by way of example only and with reference to the accompanying drawings in which:

Figure 1

is a perspective view of a building block in accordance with this invention;

Figure 2

is a side elevation of the building block of Figure 1;

Figure 3

is a perspective view of two building blocks of Figure 1 on top of which a third block of Figure 1 is located in engagement with the two bottom blocks and with mortar filling the gap between the blocks; and

Figure 4

is a side elevation of the building blocks of Figure 3.

A building block (1) is shown in Figures 1 and 2. The block (1) is generally parallelepiped shaped and has two male engaging formations (2) one an operatively upper face (3) thereof, as well as two female engaging formations (4) on an operatively lower face (5). The block (1) also has four side faces (6, 7), of which two are end faces (6A, 7A).

The upper face (3) and lower face (5) are opposed faces. The male (2) and female formations (4) are shaped and configured to permit only a portion of each male formation (2) to be received within a female formation (4).

The male formation (2) comprises a truncated square pyramid (8) which extends from the upper face (3) of the block (1). The female formation (4) comprises an aperture (9) which extends into the lower face (5) and which is complementary shaped to the truncated pyramid (8).

The height to which the pyramid (8) extends above the upper face (3) is greater by a small amount than the depth to which the aperture (9) extends into the lower face (5), to provide a gap (10) which may be filled with mortar (11) during construction of structure made form the blocks (1).

As is shown in Figures 3 and 4, a structure (12) may be formed with a plurality of the building blocks (1) stacked on each other with the male formations (2) of two blocks (13A, 13B) extending into the apertures (4) of one block (14) above it. The design of the block (1) ensures that they are all aligned consistently, both horizontally and vertically. The blocks (13A, 13B, 14) are levelled to each other by means of the flat ends of the truncated pyramids (8, 9), and the blocks are aligned with other by means of the flattened side faces of the pyramids (8, 9). The aperture (9) is referred to as a pyramid here since it is a negative of a pyramid.

As mentioned above, a gap (10) is defined between adjoining blocks (13A, 13B and 14). There is also a gap (15) between the end faces of neighbouring blocks (13A, 13B). These gaps (10, 15) may be filled with mortar (11, 16) as per normal procedure during construction.

It is therefore apparent that the block (1) design ensures consistent alignment, and that the gaps (10, 15) between adjoining blocks are also consistent. This ensures consistent strength in a wall made from the blocks and also adds to the aesthetic appeal of the structure (12). When completed, a structure built with blocks according to the invention will appear like a conventional brick wall, which adds to the appeal of using these blocks.

The construction is also simplified significantly since the blocks are self-aligning and self-levelling. This means it is possible for unskilled workers, to construct a house, for example. By making use of a base layer which includes a series of spaced apart truncated pyramids extending from it, it is possible to essentially form the foundation layer for a wall. Once the base layer is level and straight, it is possible for unskilled workers to construct the remainder of the structure.

The engaging formations also provide greater strength to a structure constructed using these blocks, since lateral movement is not only restricted by the mortar between blocks but also the engaged formations.

This makes it possible to construct a structure which is stronger than one constructed from conventional bricks or blocks, with less skilled labour and obtain better results in terms of how straight and level the construction is.

It will be understood that this is only one embodiment of the invention. It is possible to alter some aspects of the embodiment without departing from the scope of the invention.