GB2441135A

GB2441135A - Building block with spacing and alignment projections

Info

Publication number: GB2441135A
Application number: GB0616803A
Authority: GB
Inventors: Frank Brown
Original assignee: SHELMAT ENTPR Ltd
Current assignee: SHELMAT ENTPR Ltd
Priority date: 2006-08-24
Filing date: 2006-08-24
Publication date: 2008-02-27
Anticipated expiration: 2026-08-24
Also published as: GB0616803D0; WO2008023190A1; EP2059640A1; GB2441135B

Abstract

A building block 500 has a surface with a plurality of spacing projections 520 to space the block from an adjacent block and at least one alignment projection 530 to align the block with an adjacent block. The spacing projections contact an adjacent block at a point or along a line, advantageously spacing it therefrom and preventing mortar from being trapped. Each spacing projection 520 may have a curved portion and is preferably hemispherical. The alignment projection is preferably received by a recess in an adjacent block. The alignment projection may have a plurality of spaced apart raised curved portions 534, which preferably abut at a point or a line of a recess when the spacing projections abut against a surface of an adjacent block. The alignment projection permits the flow of mortar out of the recess when it is inserted therein. The projections are preferably formed on the upper surface of a block, with a corresponding recess on its lower face. The block is preferably moulded from crushed stone and cement.

Description

SPACING AND ALIGNING BUILDING BLOCKS

The present invention relates to building blocks. In particular, the present invention relates to building blocks that include spacing means and alignment means.

Building a wall is a skilled job. The builder must accurately stack the bricks or blocks on top of and next to each other with an appropriate amount of mortar in between.

While the mortar is drying, there is a limit to how far up a builder can build the wall before it becomes unstable or the mortar in the lower levels is pushed out from between the bricks due to the weight of the bricks above. This limits the speed with which even a skilled builder can work.

GB-A-2,414,707 describes a block moulding device having the capability of producing blocks with projections and corresponding recesses to help ensure that the moulded blocks are aligned properly when building a structure. One variation suggested in that application was a projection having four spines around its outer edge which would fit into corresponding recesses in another block to ensure accurate alignment of the two blocks. A lug was provided at the top of the projection to act as a spacer. The space between the two blocks could be filled with mortar or other suitable adhesive to help bind the blocks together.

It has been discovered that the projections and recesses described in GB-A-2,414,707 are not always suitable for building purposes. The proposed spacers or lugs, typically moulded from concrete, are typically too brittle to support much weight. Additionally, excess mortar often becomes trapped between the projection on one block and the recess in another, leading to uneven stacking of blocks.

The present invention provides a building block having a first surface, the first surface being provided with a plurality of spacing projections and an alignment projection. Spacing projections are provided on a surface of the block to space or separate the block from another block placed adjacent to it, typically above it, by abutting against a surface, typically a flat surface, of the other block. Spacing the blocks in this way means that a layer of mortar may be placed between the blocks and, as more blocks are stacked vertically, the weight of the blocks above will not displace the mortar. In addition to the spacing projections, embodiments of the present invention provide a separate alignment projection on the surface of the block.

The alignment projection engages or interlocks with an adjacent block so that the two blocks remain precisely aligned. The combination of spacing projections and an alignment projection allows high precision alignment between blocks in all three dimensions even in the presence of a mortar or adhesive bed.

Preferably, each spacing projection is adapted to contact an adjacent block substantially at a point or substantially along a line. Since the spacing projections only contact the adjacent block at a point or along a line (as opposed to over a two-dimensional surface), mortar does not become trapped between the spacer and the surface of the adjacent block but is easily forced out into the surrounding space. Typically, each spacing projection will have a curved surface which contacts the surface of the adjacent block in order to provide the desired point or line of contact. For example, a spacing projection may be roughly hemispherical to provide a point of contact or may be in the shape of a semicircular prism to provide a line of contact..

Preferably the alignment projection is adapted to be received by a recess in an adjacent block in order to engage with the adjacent block. Such an arrangement provides a convenient way of ensuring that the two blocks engage with one another and maintain the desired alignment.

Preferably, the alignment projection is adapted to contact against the inside of the recess in the adjacent block substantially at a point or substantially along a line. By avoiding contact between the two blocks over a surface and instead having contact only along lines or at individual points, mortar placed between the two blocks is not trapped between the projection and the block, but is forced out into intervening spaces. Points or lines of contact may be achieved by providing the surface of the alignment projection with a plurality of spaced apart raised curved portions. By raising curved portions from the surface of the projection, these curved portions abutting against an inside surface of the recess in the adjacent block, only points or lines of contact are made with a surface of the adjacent block. Furthermore, by spacing the raised portions apart from one another, space is provided for the egress of mortar as the two blocks are brought together.

In one particular embodiment, the alignment projection comprises a substantially conical frustum having a plurality of raised curved portions spaced apart around the rim of the frustum. These curved portions may each comprise a substantially semicircular prism extending the height of the frustum in order to provide a line of contact with the inside of a recess in the adjacent block.

Preferably, each raised curved portion on the alignment projection is adapted to abut against the inside surface of the recess in the adjacent block as the spacing projections abut against a surface of the adjacent block. In this way, the spacing projections and the alignment projections work in tandem to support and align the adjacent brick. With numerous lines and points of contact between the block and the block above, the weight of the block above, and any further blocks, is widely distributed thereby minimising the chance of the block cracking or breaking and maximising the number of blocks that may be stacked vertically without being forced to wait for the mortar to dry.

The present invention also provides a building block moulding device comprising a receptacle for receiving block forming material and for moulding the material into a block, the receptacle having a wall including a plurality of recesses for moulding a building block as described above.

In this way, multiple blocks having corresponding sets of a projections may be quickly and easily moulded.

Preferably, the receptacle is suitable for receiving and moulding a block forming material comprising a mixture of crushed stone and cement (i -e. concrete) . Where cement, more preferably quick drying cement, is used, a block can be moulded in a matter of seconds and used for construction purposes almost immediately.

The present invention also provides a method of moulding a building block, comprising: delivering block forming material into a receptacle, the receptacle having a wall including a plurality of recesses for moulding corresponding projections onto a block; and moulding the material into a building block as described above.

Preferred embodiments of the present invention will now be described by way of an example and with reference to the accompanying drawings in which: Figs. la, lb, 2a and 2b illustrate blocks embodying the present invention; Fig. 3 illustrates a recess in the bottom of a block embodying the present invention; Fig. 4 shows a perspective view of a block moulding apparatus; Fig. 5 shows a plan view of an adjustable block moulding receptacle having walls capable of linear movement; Fig. 6 shows a plan view of an adjustable block moulding receptacle having walls capable of linear and rotational movement; Fig. 7 shows a plan view of a mechanism for moving and adjusting the curvature of a wall of an adjustable block moulding receptacle; Fig. 8 shows a side view of the mechanism of Fig. 7; Figs. 9A, 9B and 9C show arrays of movable block moulding elements; Fig. 10 illustrates how an array of movable block moulding elements may approximate a curved surface; A block 500 embodying the present invention is illustrated in Figs. la and lb. The block 500 is shown as being cuboid with a substantially flat top surface 510.

However, many different shapes and sizes are possible, and the different surfaces of the block may be curved, curvy, angular or flat as desired. Typically, the block 500 will be given any appropriate shape in order to stack neatly with adjacent blocks. The block 500 may be formed from any suitable building material, but will typically be rnoulded from a mixture of crushed stone or sand and cement (i.e. concrete) The top surface 510 of the block 500 is provided with a plurality of projections 520, 530. These projections 520,530 are preferably formed as an integral part of the block 500.

For example, the block 500 and projections 520, 530 may be moulded out of concrete in a single mould. Alternatively, the projections 520, 530 may be separate pieces that are inserted into the surface 510 of the block 500. For example, the projections 520, 530 may be formed from plastic or other similar material and be inserted into the surface 510 of a concrete block 500 while the concrete is drying.

Figs. la and lb show projections 520, 530 provided in the top surface 510 of the block 500. This will be appropriate when further blocks are to be stacked above the block 500. Alternatively, or in addition, projections 520, 530 may be provided on one or more sides or even the bottom of the block 500 in order to engage with further blocks to the side or underneath the block 500.

The projections 520, 530 on the block 500 are of two types. A plurality of spacing projections 520 are provided to space the block 500 from an adjacent block. One or more alignment projections 530 are also provided in the block 500 to engage with an adjacent block to ensure that the two blocks are aligned in a desired manner.

Figs. la and lb show four hemispherical or dome shaped spacing projections 520 provided at the corners of the block 500. However, the number, shape and the position of the spacers 520 may be changed according to the size and shape of the block or according to other considerations such as the load that the spacing projections 520 would be required to take or even aesthetic considerations.

For example, on a block 500 having a rectangular top surface 510, additional spacing projections 520 may be provided half way along the longest edges of the block 500 to distribute the load more evenly. Additionally, for blocks 500 made from a particularly dense and/or brittle material, additional spacing projections 520 may be provided to ensure that the weight of blocks above can be supported without the spacing projections 520 breaking. For blocks 500 having a top surface 510 that is triangular or in the shape of some other polygon, spacing projections 520 may be provided at some or all of the corners and/or along some or all of the edges of the surface 510 of the block 500. Spacing projections 520 may be provided in central positions on the surface 510 of the block 500, but the central areas of the surface 510 will more normally be occupied by an alignment projection 530, as will be discussed below.

The hemispherical spacing projections 520 shown in Figs. la and lb represent a compromise between two different extremes. The first extreme is a pointed spacing projection 520 configured to contact the surface of an adjacent block at a sharp point, such as pyramidal and tetrahedral spacing projections 520. The points of such spacing projections 520 may be prone to breakage when subjected to a load whereas a curved spacing projection 520 is better at supporting the weight of another block. The opposite extreme is a spacing projection 520 which is configured to contact the surface of an adjacent block across an area or over a surface rather than at a point. Examples of this type of spacing projection 520 include cuboids or cylinders placed on end, where the surface of the adjacent block is flat. It is possible that mortar would become trapped between such spacing projections 520 and the surface of the adjacent brick, leading to uneven spacing, whereas a curved spacing projection 520 would only contact the surface of the adjacent brick at a point so that mortar does not become trapped. While all of these different types of spacing projection are possible and may be useful in some circumstances, a curved spacing projection 520 arranged to contact or abut against an adjacent brink at a single point is a preferred arrangement for the reasons discussed above.

There are a number of different preferred curved shapes for the spacing projections 520. In addition to the roughly hemispherical spacing projections 520 illustrated in Figs. la and lb, a spacing projection 520 may comprise a pillar having a curved top. The base of the pillar may be roughly cylindrical, cuboidal, pyramidal or any other suitable shape and this arrangement enables the height of the spacing projection 520 to be set at any desired level without increasing the area of the surface 510 of the block 520 that is covered by the spacing projection 520.

The spacing projection 520 may also comprise a half-cylinder (or bisected cylinder or semicircular prism) laid on ics side with the curved surface facing the adjacent block, as illustrated in Figs. 2a and 2b. Such a spacing projection 520 would contact the adjacent block along a line rather than at a point but still would not trap mortar between the spacing projection 520a and the surface of another block in the same way as a spacing projection 520 contacting the other block over a two-dimensional surface would. Nevertheless, an elongate spacing projection 520a that is roughly cuboid and contacts an adjacent block over a surface could be used if desired. Similarly, an elongate spacing projection 520a having a sharp point (such as a triangular prism) for contacting an adjacent block along a sharp line could be used if desired.

The half-cylinder spacing projections 520a in Figs. 2a and 2b are shown extending the full length of two opposing sides on the surface 510 of the block 500. Alternatively, the spacing projections 520 could be formed as smaller sections or may encircle the entire block 500. A completely closed loop may not be preferred, however, since it could cause pooling of mortar in the centre of the block 500 with no or limited air flow, leading to uneven spacing and extended drying times for the mortar.

The half-cylinder spacing projections 520a in Figs. 2a and 2b are also shown with curved end caps 525. This arrangement is preferred since it avoids sharp edges which may be prone to chipping or breakage. However, flat end caps may be provided if desired and may be easier to mould.

The purpose of the spacing projections 520 is to hold two adjacent blocks apart from one another at a desired distance. A layer of mortar placed between the blocks would then not be forced out from the space between the blocks by the weight of blocks above or by a builder pushing the blocks together. The spacing projections therefore aid a builder in constructing a wall having evenly spaced blocks.

The builder can also work faster than was previously possible because it is not necessary for him to wait for the mortar to dry before adding additional blocks to a wall.

In addition to the spacing projections 520, blocks embodying the present invention also include at least one alignment projection 530 provided on the same surface 510 of the block 500. The alignment projection 530 is configured to engage with or interlock with an adjacent block to align the two blocks in a desired manner. For a block 500 having spacing projections 520 and an alignment projection 530 on its top surface 510, the height of the spacing projections -10 -therefore determines the vertical spacing of the block 500 from a block placed above, while the alignment projection 530 constrains the two blocks to assume a particular horizontal alignment.

The alignment projection 530 engages with a recess or cavity in the adjacent block. Fig. 3 shows a block 500 having a lower surface 540 including a recess 550. The recess 550 may be provided in the block 500 in addition to the projections 520, 530 on the top surface of the block 500 so that a stack of identical blocks may be made one on top of the other. Typically, however, the bottom block in the stack would not include a recess 550, while the top block in the stack would not include any projections 520, 530.

The recess 550 is not the same shape and size as the alignment projection 530 in order to prevent mortar from being trapped within the recess 550 as the alignment projection 530 is inserted into the recess 550. Instead, the recess 550 is typically in the shape of a frustum (i.e. a truncated cone). The alignment projection 530 is adapted to contact a side surface 560 of the recess only along lines or only at points so that mortar can escape. In some embodiments, the alignment projection does not contact a bottom surface 570 of the recess 550, but is instead spaced apart from it so that mortar can sit in the gap to help join the two blocks. In other embodiments, the alignment projection 530 does contact the bottom surface 570 of the recess 550, but only at a point or only along a line.

The alignment projection 530 illustrated in the Figures is roughly frustum shaped to correspond with, although not to fit precisely within, the recess 550 in the adjacent block. The side surface 532 of the alignment projection 530 is provided with a plurality of raised areas 534. These -11 -raised areas 534 are arranged to contact the side surface 560 of the recess 570 in an adjacent block to ensure a desired alignment of the two blocks. Preferably, the raised areas 534 extend the height of the alignment projection 530 and are curved so that the contact between the raised areas 534 and the side surface 560 of the recess 550 is only along a line. Alternatively, a plurality of roughly hemispherical raised areas 534 may be provided to contact the side surface 560 of the recess 550 only at individual points. The raised areas 534 are also spaced apart from one another around the side surface 532 of the alignment projection 530 to ensure that there is a adequate path for the flow of mortar out of the gap as the two blocks are brought together.

As shown in the Figures, the raised areas or portions 534 are typically in the form of semicircular prisms extending the height of the alignment projection 530.

However, other shapes are contemplated. The raised areas 534 may be sharply pointed or have a surface for contacting the inside of the recess, although such arrangements are not preferred for the reasons discussed above in connection with the spacing projections 520.

The top surface 536 of the alignment projection 530 is shown are being substantially flat in the Figures. This flattened surface 536 does not contact with the bottom 570 of the recess 550 in the adjacent block to prevent mortar from becoming trapped between the two surfaces. Instead, as mentioned above, a space is left between the two surfaces for receiving mortar. Alternatively, the top surface 536 of the alignment projection 530 may be curved such that the curved surface 536 contacts the bottom surface 570 of the recess 550 at a point or along a line.

-12 -The shape and/or size of all of the spacing projections 520, the alignment projection 530, and the recess 550 in the adjacent block are all be configured so that the spacing projections 520 contact the adjacent block as the raised areas 534 of the alignment projection 530 contact the recess 550. If the spacing projections 520 are too large or too high such that there is no contact between the raised areas 534 and the recess 550, then the blocks will not be accurately aligned. Alternatively, if the alignment projection 530 is too large, the spacing projections 520 will not contact the adjacent block such that the alignment projection 530 alone supports the weight of the adjacent block. The spacing projections 520 and the alignment projection 530 work in synergy to provide both a desired spacing and a desired alignment.

Blocks 500 embodying the present invention may be rnoulded in any suitable fashion from materials such as concrete. However, the blocks 500 are preferably moulded using an adjustable mould so that the size and shape of the blocks 500 can easily be adjusted as desired.

A basic adjustable block moulding apparatus 10 is illustrated in Fig. 4. The apparatus includes a support surface 12 on which is mounted one or more table supports 14 for a vibratable table 16. The table supports 14 are arranged to undergo rapid oscillations of low amplitude in order to vibrate the vibratable table 16. A receptacle 18 is provided on the vibratable table 16 and is arranged to receive a block forming material and to mould the block forming material into block. Vibrations of the vibratable table 16 are passed on to the receptacle 18 and assist in the moulding process. However, vibration of the receptacle, and the precise manner in which vibration is passed onto the -13 -receptacle, is not essential and the arrangement shown in Fig. 4 is provided only as an example of one way in which vibrations can be applied if desired.

As shown in Fig. 4, the inner dimensions of the receptacle are adjustable by changing the position of a movable wall iBa of the receptacle 18. The movable wall 18a is mounted to a wall support 20 which may be moved in a linear manner either manually or under motorised or hydraulic control, or by any other suitable means. A top plate 22 for the receptacle 18 is mounted on a support 24 and can be brought down on top of the receptacle 18 as desired under manual, motorised or hydraulic control, or by any other suitable method.

In operation, the position of the movable wall 18a is adjusted by moving the wall support 20. This serves to adjust the inner width dimensions of the receptacle 18. When the receptacle 18 has been ad:justed to the desired size, a block forming material is introduced into the receptacle 18, preferably via a shute (not shown). The block forming material may be cement, preferably quick drying cement, which may have added to it a suitable quantity of crushed stone such that, when the mixture has set, the resulting block has a suitable hardness and any other desired properties. The top plate 22 is then brought down over the receptacle by moving the support 24 in order to apply pressure to the block forming material within the receptacle 18. The table supports 14 are operated to induce vibrations in the vibratable table 16 and these vibrations are passed on to the receptacle 18 and its contents in order to assist in compacting the block forming material. Once the block forming material has compacted, the vibrations are ceased and the top plate 22 and movable wall 18a are retracted so -14 -that the rnoulded block may be removed from the receptacle 18. The moulded block may be removed by hand, or a portion of the vibratable table 16 may be arranged to drop away or rise up, perhaps to an adjacent conveyor system, in order to deliver the moulded block to a builder. With a typical fast drying cement, the compacted material may be handled and used within seconds of the block forming material being delivered into the adjustable mould/receptacle 18 and compacted, and be load bearing within half an hour.

Accordingly, by using the apparatus illustrated in Fig. 1, a supply of blocks of any desired width may be quickly and efficiently produced for use by a builder.

An alternative adjustable receptacle 50 is illustrated in Fig. 5. This adjustable receptacle 50 includes three movable walls which may be adjusted in order to mould a cuboid block of selectable height and width. One wall 52 of the receptacle 50 is preferably fixed in place for improved ease of operation. However, this wall 52 may instead be movable, if desired. Each of the remaining three walls 54a, 54b and 54c are all independently movable. Each wall is mounted on a wall support 56a, 56b, 56c which passes through a housing 58a, 58b, 58c. Each wall support 56a, 56b, 56c is movable relative to the housing in a linear manner either manually or under motorised or hydraulic control or by any other suitable means. Each housing 58a, 58b, 58c is itself movable in a linear manner along an axis at right angles to the axis of movement of the wall support 56a, 56b, 56c.

Movement of the housing 58a, 58b, 58c may be achieved by placing each housing 58a, 58b, 58c on fixed rails GOa, 60b, 60c or in any other suitable way. The housing 58a, 58b, 58c can be moved and fixed at a desired position along the fixed -15 -rails GCa, 60b, GOc either manually, or under motorised or hydraulic control, or by any other suitable means.

In operation, the first movable wall 54a is manoeuvred such that one edge 62a is in contact with the inner surface of the fixed wall 52 at any desired location along the length of the fixed wall 52. The second movable wall 54b is then manoeuvred such that one edge 62b is brought into contact with the inner surface of the first movable wall 54a at any desired position along the first movable wall 54a.

The third movable wall 54c is then manoeuvred to bring one edge 62c into contact with the inner surface of the second movable wall 54b and such that the inner surface of the third movable wall 54c is brought into contact with an edge 62d of the fixed wall 52 in order to form a closed receptacle suitable for receiving the block forming material. The block forming material may then be introduced and a block moulded in the manner described above in connection with Fig. 4. Once the block forming material has set, the three movhle walls 54a. 54b, 54c are retracted so that the block can be easily removed from the mould.

Another alternative adjustable receptacle 100 is illustrated in Fig. 6. This adjustable receptacle 100 includes three movable walls which may be adjusted in order to mould a block having a cross-section of any desired quadrilateral. One wall 102 of the receptacle 100 is preferably fixed in place for improved ease of operation.

However, this fixed wall 102 may instead be movable, if desired. The remaining three walls 104a, 104b, 104c are all independently movable. Each wall is pivotally mounted to a wall support 106a, 106b, 106c via a pivot point 108a, lO8b, 108c. Each wall may be rotated relative to its support about the pivot point 108a, 108b, 108c either manually or under e -16 -rnotorised or hydraulic control, or by any other suitable means. Each wall support 106a, lO6b, lOGc passes through a housing llOa, liOb, hOc. Each wall support 106a, 106b, 106c is movable relative to the housing in a linear manner either manually, or under motorised or hydraulic control, or by any other suitable means. Each housing llOa, ilOb, hOc is itself rotatably mounted and can be rotated either manually, or under motorised or hydraulic control, or by any other suitable means. This enables rotational movement of the associated wall 104a, 104b, 104c about a second pivot access.

In operation, the first movable wall 104a is manoeuvred such that one edge 112a is brought into contact with the inner surface of the fixed wall 102. By suitable rotations of the wall 104a about the pivot points 108a and hlOa and by linear movement of the wall 104a via the wall support 106a, the edge 112a of the wall lO4a can be brought into contact with the inner surface of the fixed wall 102 at any desired location along the length of the fixed wall 102 and at any desired angle relative to the fixed wall 102. So that the first movable wall 104a can be positioned at a range of angles relative to the fixed wall 102 while still presenting an inner surface that is flat and unbroken, the edge 112a of the wall 104a is wedge shaped with a sharp edge adjacent its inner surface. Once the first movable wall 104a has been positioned as desired, the second movable wall 104b is manoeuvred to bring its wedge shaped edge 112b into contact with the inner surface of the first movable wall lO4a at any desired positionalong the first movable wall 104a and at any desired angle relative to the first movable wall 104a.

The third movable wall 104c is then manoeuvred such that its wedge shaped edge 112c is brought into contact with the -17 -inner surface of the second movable wall 104b and such that the inner surface of the third movable wall 104c is brought into contact with the wedge shaped edge 112d of the fixed wall 102 in order to form a closed receptacle suitable for receiving the block forming material. Although the positioning of the third movable wall 104c will be constrained by the positions of the other walls, the wedge shaped edge 112c of the third wall 104c may nevertheless be brought into contact with the inner surface of the second wall lO4b in any of a range of different positions such that the angle of the third wall 104c relative to the other walls may be adjusted as desired. Once all four walls have been manoeuvred into their desired positions, the block forming material can be introduced and a block rnoulded in the manner described above in connection with Figs. 4 and 5.

Each of the three adjustable receptacles described above and shown in Figs. 4, 5 and 6 have been described as having four walls for producing four sided blocks. In practice, however, a block moulding receptacle embodyinq the present invention may have three or more walls. Typically, for an n side receptacle, n-i of the walls will be movable, although all n walls could be made movable if this is desired.

Figs. 7 and 8 illustrate top and side views respectively of a mechanism 150 for adjusting not only the position and angle of the a wail 152 of a block moulding receptacle, but also the curvature of the wall 152. In such an arrangement the wall 152 could be made of hardened rubber or any other suitable material which is flexible such that suitably applied pressure adjusts the curvature of the wall 152, but is sufficiently firm to withstand forces such as moulding pressures without undergoing unwanted deformation.

-18 -The wall 152 is securely connected to at least three control rods or elements 154a, 154b, 154c, each of which is independently movable relative to a rigid back plate 156.

Each control rod may be positioned either manually or under motorised or hydraulic control, or by any other suitable means. By adjusting the different relative positions of the control rods 154a, 154b, 154c the curvature of the wall 152, and in particular the curvature of the inner surface of the wall 152, may be adjusted as desired. The rigid back plate 156 is mounted on, or formed integrally with a base plate 158. The base plate 158 is itself pivotally mounted to a support 160 via pivot point 162. This enables rotation of the wall 152 about the pivot point 162 either manually or under rnotorised or hydraulic control, or by any other suitable means. The support 160 passes through a housing 164 and is movable relative to the housing in a linear manner either manually or under motorised or hydraulic control, or by any other suitable means. The housing 164 is itself rottab1y mounted and can be rotated either manually, or under rnotorised or hydraulic control, or by any other suitable means. This enables rotational movement of the wall 152 about a second pivot access.

The adjustable curvature wall mechanism 150 described above may replace one, some or all of the walls described in connection with Fig. 6 above. The method of bringing the walls together in order to form a closed receptacle is similar to that described above in connection with Fig. 6 except that the curvature of each wall may also be adjusted as desired. In this manner a block of any desired cross-sectional shape can be moulded.

An alternative form of adjustable wall for a block moulding receptacle is illustrated in figs. 9A, 9B, 9C and -19 - 10. These figures illustrate a system with which the side of a block may be moulded having any desired curvature. The resulting block may therefore be of variable cross-section.

Fig. 9A shows an array 200 of movable rods or elements. As shown in Fig. 9A, the elements are closely packed and all have the same square cross-section in order to tessellate.

Similarly Fig. 9B shows a closely packed array 202 of elements having hexagonal cross-section. Individual elements are movable relative to each other, as shown in Fig. 9C, to create a surface of varying height. As shown in Fig. 10, with a sufficiently large array 200 of elements, a surface 204 of any desired shape may be formed.

Each element in the array 200 may be independently movable in order to provide total control over the shape of the surface to be formed. This control may be manual. For example, a builder may press an object of the desired shape against the array of elements in order to move each element to the desired position. Alternatively, an inverse of the surface that-it is desired to mould may be pressed against the back of the array of elements in order to move them to their desired positions. Once in position, the elements can be locked in place prior to moulding. Alternatively, each element may be under independent motorised, hydraulic or some other automatic control and can be accurately positioned as desired.

Each element in the array 200 need not be independently movable. Instead, the elements may be linked such that movement of one element induces movement in the surrounding elements slightly afterwards. In this way, a range of different curved surfaces may be formed by moving just a few of the elements in the array 200.

-20 -The different arrays illustrated in the figures are shown as being closely packed so that block forming material does not seep between any gaps between the elements.

However, the elements may be more loosely arranged with the moulding surface being provided with a flexible and elastic membrane. Such an arrangement may be advantageous if a perfectly smooth surface of the resulting block is desired.

An array of closely packed elements can only approximate a smooth surface and, in such a situation, subsequent grinding or sanding by a builder may be required once the block has been set. However, if a closely packed array is used, the elements do not necessarily have to have square or hexagonal cross-section, as shown in the figures, but may be of any tessellating shape or any set of shapes which, in combination, form a closely packed array.

In operation, an array of movable elements may replace one, some or all of the movable walls described above in connection with Figs. 4 to 8. An array of movable elements may also be provided for the top and bottom walls of the receptacle so that blocks of any desired shape (i.e. not necessarily having flat, parallel end surfaces) can be produced.

As discussed above, the movable or adjustable walls of a block moulding receptacle may be controlled with motors or hydraulics, preferably via a computer. A builder could use the computer to control each motor individually in order to move the walls into the desired positions. Preferably, however, the movable walls of the receptacle are under complete computer control. The builder can therefore simply input the desired dimensions of a block and the computer will automatically adjusting the position/curvature/shape of the walls in order to create a receptacle having the -21 -required inner dimensions. The builder could also select a block from a list of blocks presented to him by the computer. Alternatively, the builder could input data defining the entire structure he is seeking to build. This input data may have been created with a suitable CAD program. The computer could then break the structure down into a number of blocks and send instructions to the block making apparatus to mould the correct number of blocks of the appropriate sizes.

The quantity of block forming material to be delivered to a receptacle may be determined (perhaps by guesswork based on experience) by the builder, or a builder may pour the material into the receptacle until it is full. However, where the movable walls of the receptacle are under complete computer control, as described above, the computer control system will also be able to calculate the quantity of block forming material that is required and to either inform a builder accordingly, or else automatically deliver the correct quantity of material into the receptacle. The computer may also control a mixing apparatus to mix the correct quantity of material just before delivery into the waiting receptacle.

For the embodiments of the block making device described above, one or more walls in the block making receptacle may be provided with recesses which would form corresponding projections on a moulded block. Similarly, one or more walls may be provided with projections which would produce corresponding recesses in a moulded block. The movable elements described above could also be adjusted to create suitable recesses and projections. The recesses and projections may mould the spacing projections 520, alignment projections 530 and recesses 550 discussed above in the -22 -blocks. When combined with computer control, an entire building process could be automated with a computer controlled arm delivering moulded blocks to the appropriate positions on a structure and with the projections 520, 530 and recesses 550 ensuring that the blocks are placed accurately.

The present invention has been described by way of numerous individual examples. However, it will be understood that different features of these various examples may be used separately or in combination as desired.

Claims

-23 -

CLAI MS

1. A building block having a first surface, the first surface being provided with a plurality of spacing S projections and an alignment projection.

2. The building block of claim 1 wherein the spacing projections are adapted to space the block from an adjacent block.

3. The building block of claim 1 or claim 2 wherein the spacing projections are adapted to abut against a surface of the adjacent block.

4. The building block of any preceding claim wherein each spacing projection is adapted to contact an adjacent block substantially at a point or substantially along a line.

5. The building block of any preceding claim wherein each spacing projection has a curved portion provided to abut against a surface of an adjacent block.

6. The building block of any preceding claim wherein each spacing projection comprises either of a substantially hemispherical shape or a substantially semicircular prism.

7. The building block of any preceding claim wherein the alignment projection is adapted to align the block with an adjacent block.

-24 - 8. The building block of any preceding claim wherein the alignment projection is adapted to be received by a recess in an adjacent block.

9. The building block of claim 8 wherein the alignment projection is adapted to contact against the inside of the recess in the adjacent block substantially at a point or substantially along a line.

10. The building block of any preceding claim wherein a surface of the alignment projection is provided with a plurality of spaced apart raised curved portions.

11. The building block of claim 10 wherein each raised curved portion is adapted to abut against an inside surface of a recess provided in an adjacent block.

12. The building block of claim 11 wherein each raised curved portion is adapted to abut against the inside surface as the spacing projections abut against a surface of an adjacent block.

13. The building block of claim 11 wherein each raised curved portion is adapted to contact the inside surface substantially at a point or substantially along a line.

14. The building block of any preceding claim wherein the alignment projection is shaped to permit the flow of mortar out of a recess in an adjacent block as the alignment projection is inserted into the recess.

-25 - 15. The building block of any preceding claim wherein the alignment projection comprises a substantially conical frustum having a plurality of raised curved portions spaced apart around the rim of the frustum.

16. The building block of claim 15 wherein each raised curved portion comprises a substantially semicircular prism extending the height of the frustum.

17. The building block of any preceding claim further having a second surface opposite the first surface, the second surface adapted to abut against one or more spacing projections on an adjacent block to space the block from the adjacent block and being provided with a recess for receiving an alignment projection in an adjacent block to align the block with the adjacent block.

18. The building block of any preceding claim wherein the block is moulded from a mixture of crushed stone and cement.

19. A building block moulding device comprising: a receptacle for receiving block forming material and for moulding the material into a block, the receptacle having a wall including a plurality of recesses for moulding a block according to any preceding claim.

20. A method of moulding a building block, comprising: delivering block forming material into a receptacle, the receptacle having a wall including a plurality of recesses for moulding corresponding projections onto a block; and -26 -moulding the material into a block according to any of claims 1 to 18.

21. A building block substantially as hereinbefore described with reference to the accompanying drawings.

22. A method of moulding a block substantially as hereinbefore described with reference to the accompanying drawings.

CLAIMS

1. A building block having a first surface, the first surface being provided with a plurality of spacing projections and an alignment projection, wherein each spacing projection is adapted to contact an adjacent block sdbstantially at a point or substantially along a line.

2. The building block of claim 1 wherein the spacing projections are adapted to space the block from an adjacent block.

3. The building block of claim 1 or claim 2 wherein the spacing projections are adapted to abut against a surface of the adjacent block.

4. The building block of any preceding claim wherein each spacing projection has a curved portion provided to abut :. against a surface of an adjacent block. * 20 **S*

5. The building block of any preceding claim wherein each spacing projection comprises either of a substantially hemispherical shape or a substantially semicircular prism.

:.:.. 25 6. The building block of any preceding claim wherein the alignment projection is adapted to align the block with an adjacent block.

7. The building block of any preceding claim wherein the alignment projection is adapted to be received by a recess in an adjacent block.

8. The building block of claim 7 wherein the alignment projection is adapted to contact against the inside of the recess in the adjacent block substantially at a point or substantially along a line.

9. The building block of any preceding claim wherein a surface of the alignment projection is provided with a plurality of spaced apart raised curved portions.

10. The building block of claim 9 wherein each raised curved portion is adapted to abut against an inside surface of a recess provided in an adjacent block.

11. The building block of claim 10 wherein each raised curved portion is adapted to abut against the inside surface as the spacing projections abut against a surface of an adjacent block.

12. The building block of claim 10 wherein each raised curved portion is adapted to contact the inside surface substantially at a point or substantially along a line. S. **

* *. . * . *. 13. The building block of any preceding claim wherein the * alignment projection is shaped to permit the flow of mortar .:.. 25 out of a recess in an adjacent block as the alignment *..* projection is inserted into the recess.

14. The building block of any preceding claim wherein the alignment projection comprises a substantially conical frustum having a plurality of raised curved portions spaced apart around the rim of the frustum.

15. The building block of claim 14 wherein each raised curved portion comprises a substantially semicircular prism extending the height of the frustum.

16. The building block of any preceding claim further having a second surface opposite the first surface, the second surface adapted to abut against one or more spacing projections on an adjacent block to space the block from the adjacent block and being provided with a recess for receiving an alignment projection in an adjacent block to align the block with the adjacent block.

17. The building block of any preceding claim wherein the block is moulded from a mixture of crushed stone and cement.

18. A building block moulding device comprising: a receptacle for receiving block forming material and for moulding the material into a block, the receptacle having a wall including a plurality of recesses for moulding **,* 20 a block according to any preceding claim. * S

19. A method of moulding a building block, comprising: delivering block forming material into a receptacle, : * the receptacle having a wall including a plurality of *** 25 recesses for moulding corresponding projections onto a S * block; and moulding the material into a block according to any of claims 1 to 17.

20. A building block substantially as hereinbefore described with reference to the accompanying drawings.

21. A method of moulding a block substantially as hereinbefore described with reference to the accompanying drawings. S. * S * S.. S... * * *S*. S. **

* ** . * S S... * S * . . *.S. *... * . S...