The present invention relates to interlocking blocks and more particularly blocks interlocking in all three dimensions without the need for binding agents or support structures. BACKGROUND OF THE INVENTION

Bricks have been employed in construction work for thousands of years. Many improvements have been made over the years and several new materials of construction have been developed. Interlocking bricks are a recent development in the field of brick making and usually use a material like concrete. A major advantage of these bricks over the conventional cuboidal clay bricks is that there is no need to check alignment after each layer of bricks has been placed. The interlocking bricks are identical iwith each other and self-aligning by design. Thus, highly skilled labor needn't be employed which significantly cuts down labor costs. Many interlocking bricks are hollow to achieve low weight per unit volume, thus reducing material costs without compromising much on the strength.

The prior art comprises of a number of interlocking blocks or bricks using different interlocking mechanisms. WO 00/19026 proposes a bi-directionally interlocking hollow brick which possesses interlocking passageways in two directions. A major drawback of these bricks is that they require reinforced concrete to provide structural stability. Also, there is no provision to stack two layers of bricks together, so only single-layered walls are possible. Moreover, edge and corner blocks aren't well established.

US Patent no. 3,936,987 discloses a concrete block with grooves at its opposite ends and centre. A drawback of using these blocks is that epoxy cement binder is needed for bonding of courses in a customized wall. Also, only single layered walls are possible because interlock is possible in just two directions. Moreover due the presence of wedges for interlocking the blocks, replacement of blocks isn't easy.

US Patent no. 5,901,520 reveals light weight interlocking blocks where a number of notches and projections are provided for interlock. Due to the large number notches and projections in each block, fabrication of such blocks isn't very easy. Moreover, these blocks have empty space for insulation and sound proofing but it is insufficient for fitting pipes and electrical installations. Also, such blocks are only useful in constructing external walls, load bearing walls, retaining walls and sound absorbing walls since the blocks are always hollow and can't interlock in three dimensions.

US Patent no. 7,661,239 discloses a dry masonry brick, provided with a plurality of channels which are arranged so that they can receive a projection from one or more adjacent bricks in an interlocking relation. However, these bricks have the limitation of needing a fastening element or support structure to connect the bricks to a support structure or substructure for additional stability. Moreover, replacement of bricks however possible is cumbersome due to the usage of the supports. Furthermore, since two side faces are flat, the wall constructed by these bricks can only have single layers.

US Patent no. 7,833,077 discloses pixel-blocks configured as picture elements to be used in the construction of various two-dimensional and three-dimensional graphic blocks. However, these pixel-blocks have very low tolerances such that their usability is only contemplated for graphic artifacts. Moreover, cylindrical posts and post holes are needed to form three dimensional configurations which are limited to specialized graphic artifacts. The grooves are designed in such a manner that interlock is only possible in two dimensions. Thus, the pixel-blocks are restricted only to graphic applications.

US Patent no. 7,625,261 discloses interlocking toy blocks. These can be made into various shapes which are similar to their real life equivalents. The problem with these blocks is that they are suited for recreational purposes only as the interlock isn't very strong. Only plastics can be primarily used due to the low thickness of the blocks.

Most existing interlocking bricks blocks are restricted to building construction and use reinforced concrete after assembling the structure. This leads to several disadvantages explained hereinafter.

Most bricks designed in accordance with the prior art require some fastenings or support structures or reinforced concrete because they aren't very stable on their own. Concrete requires highly skilled labor at every stage from mixing to pouring to hardening. Pouring concrete is a time consuming process since it requires careful planning. Also, a lot of time is required for setting of the concrete ranging from a few hours to an entire day. The strength of a concrete based structure is highly reliant on the chemical composition of the batches of concrete that have been used to construct the structure and is extremely difficult to control. This means that small errors or miscalculations in mixing the individual components, the time taken to pour the concrete or the time given for the concrete to set, may compromise the integrity of the entire structure. It is for this reason that every stage needs to be carefully supervised by an expert or an experienced worker, which consumes both time and highly skilled labor.

Fractures in structures using concrete occur at the microscopic level and propagate very quickly to all of the parts. Since any structure using concrete is essentially interconnected, a fracture in any one part of the structure can propagate to another part thus compromising the entire structure instead of being just a localized failure. Also, since the fractures that occur are microscopic in dimension, it is nearly impossible to detect them unless specialized equipment like ultrasound scanners are used, which make the maintenance process even more complicated. Even when fractures are detected, the only solution is to plaster the fractured region. This does not eliminate the faults which caused the fracture, but simply patches them up. In case of an interlocking brick structure reinforced with concrete, it isn't possible to remove a section of the structure and replace it with a stronger, possibly newer section which removes the faults in the earlier section. The only other alternative is to tear down the entire structure and reconstruct. Also, structures built using concrete usually have piping for electrical connections and plumbing embedded directly into the concrete and brick. This causes a problem when they have to be replaced since the process may involve breaking the concrete or bricks around them to release them from the structure which may cause fracturing of the concrete.

Concrete is susceptible to shocks, especially those caused by earthquakes. These shocks, even though they may not cause structural collapse may induce fractures and failures in many regions at once compromising structural integrity.

Also, concrete being porous allows water to seep through which can greatly compromise both its strength and eventually the structural integrity. To prevent this, usually the concrete has to be coated with waterproofing agents which also have to be periodically checked and replaced.

Concrete in itself is insufficient to reinforce structures made from interlocking bricks. Thus, expensive materials like steel rods are inserted to provide strength which further drives up the cost of construction.

Since concrete does not bind with every material found in nature, the substances that can be used to make the interlocking bricks and other construction materials are restricted and therefore new materials with far greater properties than these materials are not useable for construction.

Concrete is porous so eroded by water and susceptible to fire and other natural hazards. The only protection method is to coat concrete structures with fireproofing and waterproofing chemicals. Since these chemicals may erode over time and need to be replaced periodically, it poses a threat to the structure at a time when it requires re-proofing.

In the prior art, tearing down a concrete reinforced structure is a very time consuming process, labor intensive, causes extreme inconvenience to the people in the immediate neighborhood due to noise generated by equipments like jackhammers and is also extremely dangerous when substances like dynamite are used to create controlled explosions to bring down large structures. Moreover, this process requires specialized labor for handling concrete breaking equipment, handling explosive equipment etc. It is an object of the invention to avoid or mitigate the disadvantages set out above. Unlike the prior art, the current interlocking blocks are easy to assemble and do not require any specialized skilled labor or supervision of every little detail. The blocks are bulk manufactured and do not require any binder, mortar, cement etc. in the construction. The blocks just slide into one another which saves time and labor costs because semi-skilled labor can be used in the construction process. Since these interlocking blocks have no elements that need to inserted, set or harden, they can build structures much faster as every new layer can be started as soon as the previous layer has been assembled.

The strength of the interlocking blocks is based on the material used for manufacture and therefore represents uniformity since the processes used to manufacture materials and their strength is standardized thus representing a greater reliability in the blocks produced. These blocks can interlock in one or more planes, thus providing immense strength. Even though the exact tensile strength of every individual block may vary, this variation is usually very minute and the tolerances imposed within the standards are very low. Also manufacturing technology is currently capable of manufacturing very high quantities of material at microscopically low levels of error in any parameter.

Moreover, these interlocking blocks are not connected to each other on the atomic and molecular levels. Thus, a fracture in one block will not propagate to another block even adjacent to it, let alone further along the structure. Hence failures, if any, will be localized and can be corrected without the situation escalating to a high risk scenario.

Since the interlocking blocks are not held together by strong chemical bonds, they can easily be slid out whenever a block needs maintenance or replacement. In this way a fractured block can be replaced with an entirely new block thus eliminating the faults in the original block.

The interlocking blocks are free to vibrate relative to each other since they have no binding agent between them. This gives them a shock absorbing quality which is extremely useful in combating earthquakes and even high winds. The energy of the earthquake or winds is dissipated through the vibrational energy of the blocks and thus no energy goes into fracturing the material of the structure itself.

Interlocking blocks can be standardized and mass produced and can also be used to create prefabricated structures. Different types of prefabricated structures find use in mass produced houses, solar cell panels, etc. In case of prefabrication several blocks can be assembled at a convenient location and then easily installed at the site, thus saving a lot of installation time. This would make possible the availability of extremely cheap but also extremely good quality housing since the simplicity of manufacture and assembling of these structures would considerably save costs.

The interlocking blocks can be manufactured from materials such as metals and can be polished to a smooth finish. This reduces wear and erosion from natural elements like rain and winds etc. These interlocking blocks can bring new age materials like carbon fiber, composites and alloys like aircraft grade aluminum into the construction industry. Because almost any material can be used to manufacture these blocks, their properties can also be controlled to a much greater extent. These properties include strength, weight, resistance to hazards such as fire, reaction to water etc. The blocks can also be manufactured using environment friendly materials.

The interlocking blocks can be made hollow which provides the opportunity to pass pipes for electrical connections, water ^" and other amenities. Also since these pipes are not bound to the block itself they can easily be pulled out and replaced or maintained without much effort and without causing much damage to the structure. Moreover, many technological systems like integrated circuits and pixels for video display can be embedded into one or more faces of the interlocking block thus creating a smarter structure and saving on the space which would otherwise have been occupied by these appliances within the structure.

Tearing down interlocking block structures is a matter of simply dismantling the blocks one by one in a sequence opposite to the sequence in which they were assembled. The entire structure can be disassembled quickly and without using any specialized equipment or equipment that requires specialized training to handle. The labor employed to assemble the structure can also easily dismantle it.

The interlocking blocks of the current invention can be constructed using plastics, concrete, carbon fibers, steels, alloys, nano-materials etc. Thus, it is possible to make a complete wall with interlocking blocks of same or different dimensions and also different materials. One could use plastic blocks in conjunction with fiber optic cables for graphic displays. Additionally, due to the symmetry in the design of the blocks, corner and edge blocks can be fabricated easily by making the required number of faces flat. Many variations of the blocks are possible, so it can be used in various embodiments to perform many different functions after slight modifications. SUMMARY OF THE INVENTION

It is an object of the invention to provide interlocking, self-aligning, multi-purpose blocks useable in construction, piping, prefabricated structures etc. The blocks are capable of interlocking with one or more adjacent blocks using complimentary depressions and projections capable of traversal. The blocks can interlock in all three directions so as to provide immensely strong three dimensional arrangements unlike the prior art. The interaction between adjacent blocks is so strong that no binding or fastening materials are needed.

The blocks of the current invention can be made from a multitude of materials using their respective fabrication techniques. For instance, plastic blocks can be manufactured using injection molding technique which is well established. Metallic blocks can be made using various casting techniques. Hollow blocks can be formed by bending a material that bends easily to the desired shape. Blocks made from semi-conductor materials can be formed using 3-D printing. The embodiments mostly focus on the shape of the blocks since numerous materials can be used by applying the required manufacturing process.

In accordance with an embodiment of the invention, is provided a block for forming three dimensionally extendable structures, comprising at least one interlocking feature on a plurality of its surfaces. The block characterized in that it is interlockable with other similar blocks at three or more of its non-parallel surfaces.

In accordance with another embodiment of the invention, is provided a block, wherein the interlocking features are in the form of a projection or depression that are complimentary in shape; the shape comprising a neck portion and a significantly larger head portion, such that a projection-depression pair can slide in and out only in one direction.

In accordance with yet another embodiment of the invention is provided a block which is substantially parallelepiped in shape discounting projections and depressions. The block configured such that at least one pair of parallel and opposite faces are complimentary or identical to each other.

In accordance with yet another embodiment of the invention is provided a block which is substantially cuboidal or cubic in shape discounting projections and depressions. The block characterized in that it is interlockable with other similar blocks at three or more surfaces substantially orthogonal to each other.

In accordance with yet another embodiment of the invention is provided a block having a plurality of through holes parallel to at least one pair of opposite faces, such that the holes pass through and substantially perpendicular to the interlocking features on the opposite faces.

In accordance with yet another embodiment of the invention is provided a block having the interlocking features on at least one pair of opposite faces as toothed such that they can slide into interlocking features on other similar blocks in only one direction.

In accordance with another embodiment of the invention is provided a block having a cavity normal to a pair of opposite faces. The cavity extends partially or fully up to the length of the remaining faces of this hollow block. In accordance with yet another embodiment of the invention, the hollow block has a plurality of ribs inside the cavity; the ribs beings substantially perpendicular one or more surfaces of the block so as to provide strength in particular direction(s).

In accordance with yet another embodiment of the invention, the hollow block is partially made up of honeycomb shaped structures at its regions which are in close proximity with the cavity. In accordance with yet another embodiment of the invention, the hollow block has a swingable door on one of the faces normal to the cavity.

In accordance with yet another embodiment of the invention, the hollow block has interlocking features on at least one pair of opposite surfaces, extending partially along the length/width. In accordance with another embodiment of the invention is provided a block comprising- two pairs of Opposite, parallel and substantially L-shaped surfaces provided with interlocking features on at least one of the pairs; and, a pair of surfaces in the shape of a parallelogram at the two distal ends of the L-shaped surfaces.

In accordance with another embodiment of the invention, the block is substantially cylindrical in shape with a plurality of interlocking features extending lengthwise on the curved surface of the blocks; and at least an interlocking feature is provided on each of the opposite and non-curved surfaces.

In accordance with another embodiment of the invention is provided a block which is substantially hollow cylindrical in shape with a plurality of interlocking features extending lengthwise on at least one of the curved , surface of the blocks.

In accordance with yet another embodiment of the invention, the block has an electrical/electronic circuit or part of it etched or embedded on at least one of its faces.

In accordance with another embodiment of the invention, the block comprises at least two coaxial, contiguous and substantially cylindrical sections having a plurality of interlocking features on the curved surface(s); characterized in that the inner curved surface of one portion is complimentary with the outer curved surface of the other portion.

In accordance with another embodiment of the invention, the block comprises at least two coaxial and substantially hollow-cylindrical sections having a plurality of interlocking features on the curved surface(s). The block characterized in that the inner curved surface of one portion is complimentary with the outer curved surface of the other portion.

In accordance with yet another embodiment of the invention, the block is provided with a layer of viscoelastic material on at least one of the surfaces of the block.

In accordance with another embodiment of the invention is provided a linear chain formed using several similar or dissimilar blocks of the invention. In accordance with another embodiment of the invention is provided a sheet or array formed using several similar or dissimilar blocks of the invention.

In accordance with another embodiment of the invention is provided three dimensionally extendible structure(s) formed using several similar or dissimilar blocks of the invention.

In accordance with yet another embodiment of the invention the linear chain of blocks has at least one hole passing through at least one depression-projection pair from adjacent interlocking blocks; and at least a fastening element engage-able with the hole.

In accordance with yet another embodiment of the invention the sheet or array of blocks is used in a solar cell panel or pixellated display screen or for vertical farming.

It is another object of this invention to provide interlocking blocks that can be configured to provide hollow walls. These can be insulated, sound proofed and/or fitted with electrical wiring and piping utilizing the hollow portion of the wall.

It is another object of this invention to provide blocks with interlocking features that make it easy to assemble or disassemble them into a multitude of formations. The blocks are self aligning in the plane of the interlock.

It is another object of this invention to provide interlocking blocks useable for production of prefabricated structures for construction and elsewhere. The blocks can be assembled at a suitable location and then moved to the site where they can be fitted easily using the interlocking mechanism, thus saving a lot of installation time.

It is another object of this invention to provide interlocking blocks that are free to vibrate in any direction since there is no binding agent in between them. The blocks are so placed that the ability to vibrate provides them with shock resistance which is extremely useful in combating earthquakes and high winds.

It is another object of this invention to provide semi-hollow or hollow interlocking blocks useable as a containment unit for different objects. In various embodiments the block can be used to house solar cells, video display components, soil for vertical farming, etc.

It is another object of this invention to provide interlocking blocks that have good damping, noise absorbing and insulating properties. Such blocks find utility in a variety of buildings.

In a preferred embodiment of the current invention, an interlocking block with generally cubic outline is provided. The block has depressions in the form of a recessed groove at an intermediate location on three of the faces. The remaining three faces opposite to the above mentioned faces have a projection in the form of a tongue or blob at an intermediate position. Thus, no two opposite faces will have the same feature in the present embodiment. The grooves and tongues have complimentary mating shapes such that they fit tightly into one another when so configured. The tongues and grooves preferably cover the complete length of a face. The projection has a significant head portion which can fit into the recessed groove thereby constricting its movement. The tongues and grooves are so configured that they are disposed to slide into each other when placed parallel to each other. Thus, a tongue from one block can slide into the groove of another block so as to restrict their motion in directions normal to the direction of the sliding motion. This interlock can be replicated using corresponding faces of other blocks, thus forming a linear chain of interlocked blocks. Thus, the two faces containing the tongue and groove involved in the interlock get superimposed. The only degree of freedom available to the blocks is in the direction of the sliding motion. Additional blocks can now be added to any pair of faces parallel to each other and adjacent to the face superimposed earlier. The blocks are allowed to slide into each other and as a result a complete sheet is formed. Blocks in the interior of the sheet are left with zero degrees of freedom. Further, a plurality of identical sheets is capable of sliding into each other in one direction. Thus, it is preferable to stack the sheets one over the other by utilizing the sliding motion. In this way, three dimensionally extendable structures can be formed using interlocking blocks of the current invention.

It is worth reiterating that the blocks once assembled can also be disassembled by reversing the steps used in assembling. Thus, the blocks can be removed block by block or row by row or sheet by sheet as may be the case.

In another preferred embodiment, an interlocking block similar to the one described above is formed by making one of the surfaces devoid of any interlocking elements. The flat surface is generally the visible portion of the blocks in a structure constructed using these blocks. Thus, the surface opposite to the flat surface may or may not have a complimentary surface capable of interlocking with that surface. The most important application of the said embodiment is in the fabrication of sheets which is discussed hereinafter.

The general outline of the block is also cubic and the depression or grooves and projections or tongues are placed at intermediate positions on the surfaces of the block. Thus, interlocking of a pair of blocks is possible by superimposing two faces of the pair of blocks in the same manner as explained earlier. The sliding motion is permissible in a direction normal to the flat surface. The continuous flat surface thus formed can be utilized for constructing a hollow wall which is suitable for housing purposes. In another embodiment, a pair of opposite sides in made flat so that a single layered wall can be formed having flat external surfaces on both sides. Flat sheets so formed can also be used in graphical artifacts or display units by inserting optical fibers in each block. The preferred embodiments stated above demonstrate the most basic forms of the current invention. Many variations are possible by changing the features on the faces, changing the shape of the faces, reducing the number of possible interlocks, changing the form of the tongues and grooves, changing the material of the block, making the block hollow etc. Other objects and features of the invention will be apparent from the following detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF DRAWINGS

The above and further objects, features and advantages of the current invention will be explained more fully from the detailed description taken with the accompanying drawings in which:

FIG. 1 A is a perspective view of an interlocking block of the present invention.

FIG. IB is a front view of the block of FIG. 1A showing a face where outline of a tongue and groove is visible.

FIG. 1C is a magnified view of the tongue of the block of FIG. 1 A assembled into a groove of a second similar block.

FIG. 2 A is a perspective view depicting 3 blocks of FIG. 1 A interlocked in a linear structure.

FIG. 2B is a perspective view depicting 9 blocks of FIG. 1 A interlocked in a 3x3 structure.

FIG. 2C is a perspective view depicting 27 blocks of FIG. 1 A interlocked in a 3x3x3 structure.

FIG. 2D is a perspective view depicting a pair of blocks of FIG. 1A interlocked by using a pair of fastening elements in addition to the interlock as shown in FIG. 2A.

FIG. 2E is a magnified view of the encircled area of FIG. 2D.

FIG. 3A-C are perspective views of blocks similar to the block of FIG. 1A but with different tongue/groove profiles.

FIG. 4 A is a perspective view of a block resembling the block in FIG. 1 A but with one face flat. FIG. 4B is a perspective view of a block resembling the block in FIG. 4A but with two adjacent faces made flat.

FIG. 4C is a perspective view of a block resembling the blocks in FIG. 4A and 4B but having three faces sharing a common vertex as flat.

FIG. 5 A is a perspective view depicting 3 blocks of FIG. 4A interlocked in a linear structure. FIG. 5B is a perspective view depicting 9 blocks of FIG. 4 A interlocked in a 3x3 structure.

FIG. 5C is a perspective view depicting a pair of blocks of FIG. 4A interlocked by using a pair of fastening elements in addition to the interlock as shown in FIG. 5A.

FIG. 6 A is a perspective view comprising a pair of toothed blocks of FIG. 3B showing the toothed tongues and grooves. FIG. 6B is a schematic diagram showing the tooth profile and the interlock of toothed tongues and toothed grooves of the two blocks in FIG. 6 A.

FIG. 7A and 7B are perspective views of blocks similar to the block of FIG. 4A but with different tongue/groove profiles.

FIG. 8 A is a perspective view of a hollow version of the block of FIG. 1 A.

FIG. 8B is a perspective view of a hollow version of the block of FIG. 4 A.

FIG. 8C is a perspective view of a block similar to the block of FIG. 8 A made semi-hollow. FIG. 8D is a perspective view of a section of the block of FIG. 8C.

FIG. 9A is a perspective view of a block resembling the block of FIG. 1A in which all the faces have grooves.

FIG. 9B is a perspective view of a block resembling the block of FIG. 9 A in which one of the faces is flat.

FIG. 1 OA is a perspective view of a block resembling the block of FIG. 8 A having internal ribs in the hollow portion.

FIG. 1 OB is a front view of the block of FIG. 10A showing the outline of the internal ribs.

FIG. IOC is a sectional view of the block of FIG. 10A taken on the line AA' of FIG. 10B.

FIG. 11 A is a front view of a block similar to the block of FIG. 8 A having honeycomb structures in the region surrounding the hollow portion.

FIG. 11 B is a sectional view of the block of FIG. 11 A along the line AA' .

FIG. 12A is a perspective view of a block similar to the block of FIG. 8C having a swingable door attached to it.

FIG. 12B and 12C are perspective views of the block of FIG. 12A with the door in open position.

FIG. 13A is a perspective view of a block similar to the block of FIG. 1A having a layer of viscoelastic material on its faces.

FIG. 13B shows a section of the block of FIG. 13 A along the y-z plane and the layer of viscoelastic material can be seen in the shaded region.

FIG. 14A and 14B are perspective views of a block similar to the block of FIG. 8C with a pair of tongue and groove on opposite faces reduced in length.

FIG. 15 is a schematic view of a pixellated display screen formed using blocks of the invention. FIG. 16 is a perspective view of a solar cell panel formed using blocks of the invention.

FIG. 17A and 17B are perspective views of an L-shaped block for buildings.

FIG. 18 A, 18B, 18C and 18D are perspective views of substantially cylindrical interlocking block for constructing pillars. FIG. 19A is a perspective view of a ring type of block which has grooves on its inner curved surface.

FIG. 19B and 19C are perspective views of a substantially cylindrical pillar formed using the blocks of FIG. 18A and FIG. 19A.

FIG. 20A and 20B are perspective views of a block usable for construction of pillars.

FIG. 21 A, 21B and 21 C are perspective views of blocks in the form of hollow cylinders and having tongues and/or grooves on the outer curved surface like the blocks shown in FIG. 18A, 18C and 18D respectively.

FIG. 22A and 22B are perspective views of an interlockable pipe of the invention.

FIG. 22C is a sectional view of the pipes of FIG. 22 A and 22B interlocked together.

FIG. 23A and 23B are perspective views of pipes similar to the pipes of FIG. 22A and 22B respectively having the location of tongues and grooves interchanged.

FIG. 24A is a front view of a block having a PCB attached on its front face.

FIG. 24B is a front view of a block having an electronic circuit etched on its front face.

The orientation of the axes is as marked in FIG. 1A for FIG. 1-14. The orientation of the axes can be assumed to be the same even if not shown explicitly for each figure. The x-axis denotes the horizontal direction, y-axis denotes the vertical direction and z-axis is in a direction into the plane of the paper.

Reference will now be made in detail to the present embodiments and methods of the invention as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the drawings. It should be noted, however, that the invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described in this section in connection with the embodiments and methods. The invention according to its various aspects is particularly pointed out and distinctly claimed in the attached claims read in view of this specification, and appropriate equivalents.

DESCRIPTION

Discussed below are some representative embodiments of the current invention. It is understood, however, that other interlocking blocks having other shapes and dimensions are contemplated within the scope of the invention. The invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described in this section in connection with the embodiments and methods. The invention according to its various aspects is particularly pointed out and distinctly claimed in the attached claims read in view of this specification, and appropriate equivalents. It is to be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

FIG. 1 A shows a perspective view of a block 10 of the present invention. The faces are labeled as face 16 or front, face 18 or right, face 20 or left, face 22 or back, face 24 or top and face 26 or bottom face. We shall use the same convention to refer to corresponding faces in other embodiments possessing similar orientation and shape of the blocks. Block 10 has three faces (20, 22 and 26) that have depressions or recessed grooves 12 and the three opposite faces (18, 16 and 24) have x)mplimentary projections or tongues 14 that can fit into such grooves. The tongues and grooves have nearly identical mating outline shapes and are located at the centre of each face such that it divides the remaining face into two parts. Thus, each face has a tongue or groove protruding out or recessing in respectively, and two flat portions 28 and 32 lying in the same plane.

The tongues are oriented orthogonally with respect to each other such that they are either parallel or perpendicular to any edge of the block as can be seen in the figure. The three faces containing tongues share a common comer. The same applies to the grooves as well. The groove 12 is slightly larger to accommodate a mating tongue 14' from an adjacent block. The complimentary symmetry allows adjacent blocks to be interlocked together by a sliding motion along the z-axis.

The edges of the block may or may not be rounded. The tongues and grooves need not necessarily be placed parallel or perpendicular to the edges of the block but can be at any other angle to the edges. Moreover, a tongue or groove can be placed along any other line on a given face as long as the other tongues or grooves are respectively orthogonal to them. Furthermore, the tongues and grooves needn't take symmetrical shapes like the ones shown in FIG. 1A and FIG. 3 A-C but can take other asymmetric shapes as well.

FIG. IB is a front view of block 10 showing the face 16 shown in FIG. 1A. This face has a tongue 14 at its centre and two flat portions 28 and 32. Also visible are a groove 12 of face 20 and a tongue 14 of face 18. On sliding tongue 14 of face 18 into a groove 12' of face 20' of block 10' along the z-axis, the faces 18 and 20' get interlocked.

FIG. 1C is an enlarged view of the interlocked tongue and groove from FIG IB. Let the opposite sides of the tongue 14 as shown be named as faces A and B and those of the groove 12' as faces A' and B' in such a way that face A is in contact with face A' and so on. The faces C and C are parallel to the y-z plane. The gap between the tongue and groove as shown in the figure has been exaggerated and the tongue and groove faces have been changed to straight lines for the sake of clarity. The gap is generally very small or may not even be present.

In this configuration, translational movement of the blocks relative to each other along the x- axis is restricted by the interactions of faces A with A', B with B' and C with C\ The relative translational movement along the y-axis is restricted by the interactions of faces A with A' and B with B'. All six faces contribute towards restricting relative rotational movement along all three axes. The only relative translational movement permissible in this configuration is along the sliding movement of the tongue within the groove. This degree of freedom can also be constrained by adding a second layer of blocks behind the joined blocks 10 and 10'. However, the blocks are free to vibrate in any direction.

FIG. 2A shows blocks 10 and 10' interlocked as described in figures 1A-1C. Another block 10" is interlocked in the opposite direction in a similar manner by sliding motion along groove 12 of face 20. More blocks can be assembled together by sliding them in across the z-axis, thus forming a linear chain. Sliding of more blocks is possible in the direction of x and y axes, giving rise to sheet and three, dimensionally extendable structures as explained in the following figures. FIG. 2B shows nine blocks interlocked together by first sliding three more blocks along x-axis into grooves 14, 14' and 14" of face 24, 24' and 24" of blocks 10,10' and 10" respectively. Another three blocks are then slid in a similar manner along the x-axis to superimpose on faces 26, 26' and 26", thereby forming a 3x3 sheet structure.

One may observe that three continuous rows of 3 tongues each are formed in the front faces corresponding to face 16 of block 10. A similar layer of grooves is formed on the back faces corresponding to face 22 of block 10. These continuous channels so formed are very useful as will be illustrated later.

FIG 2C shows twenty seven blocks interlocked by sliding two identical sheets of nine blocks as shown in FIG. 2B, along the y-axis. The continuous rows of tongues are slid into their corresponding rows of grooves by sliding them along the y-axis so as to lock block 10 of figure 1 A from all directions.

FIG. 2D shows an alternate way of completely locking a linear chain formed using blocks identical to block 10. Here, an interlock is achieved by sliding the blocks along the z-axis in the same way as explained in FIG. 1A-C and FIG. 2 A. The blocks as arranged in FIG. 2 A are disposed to slide in an out of each other in the direction of the z-axis, so movement is possible in one direction. In the given figure, fastening elements 34 and 34' are inserted between a pair of blocks after creating one pair of through holes per block. The holes pass through the groove- tongue pair involved in the interlock, thus constricting the relative motion of the blocks in the direction of z-axis as well. The holes 36 and 36'are visible on the tongue of block 10'. I this way, a linear chain of blocks is formed which have no degrees of freedom available to them. The blocks can be disassembled only after removal of the fastening element.

FIG. 2E shows a magnified view of the encircled area of FIG. 2D. It shows how tongue 14 of face 18 of block 10 is interlocked with groove 12' on face 20' of block 10' and a fastening element 34 passes through both of them. Thus, translational motion is completely arrested as explained in the preceding paragraph.

FIG. 3A-C depict three alternative shapes of the tongues and grooves for block 10 of FIG. 1 which can also be used to implement interlocking blocks of the present invention. The tongue- groove shapes have been used interchangeably in the following figures, without diverging from the scope of the invention. The basic requirement of this shape is to provide significant head and neck portion which can't slide out of the grooves. They should be detachable only by sliding the blocks in the direction opposite to the sliding motion and/or in the direction of the sliding motion.

FIG. 3 A has grooves and tongues similar to FIG. 1 with the difference of having rounded faces. FIG. 3B has one pair of tongue-groove toothed to provide even better contact and higher stability. The basic outline of the other two tongue-groove pairs however is the same as block 10 of FIG. 1. The toothing is such that the tongue once slid into the groove can't slide back out in the opposite direction. Thus, these blocks can be used for building strong permanent structures without using any adhesives or reinforcement. FIG 3C is another form with completely rounded tongues and grooves. These grooves can be preferred in some embodiments.

FIG. 4A depicts block 10 of FIG. 1A with one face completely flat because of being devoid of a tongue or groove. Face 16 shown in FIG. 1 A has been made flat. The other faces are available for interlocking in the same manner as explained in FIG. 1A-1C. This block is useful for providing a flat surface for the outer surface of a sheet or three dimensionally extendible structures explained in FIG. 2B-C above.

FIG. 4B shows an edge block useable on the edges of sheet and three dimensionally extendable structures as explained in FIG. 2B-C. Edge blocks require 2 flat faces due to only four interlocks. Thus either one of faces 18, 20, 24 and 26 is made flat in addition to face 16 which is already flat according to FIG. 4A. In the given figure, face 20 is made flat.

FIG. 4C shows a corner block useable in sheet and three dimensionally extendable structures as described in FIG. 2B-C. In this case, three faces corresponding to block 10 of FIG. 1 are made flat because only 3 interlocks are required. Face 16 is already flat in accordance with FIG. 4 A. The other two flat faces can be either of 24 and 18, 18 and 22, 22 and 20 or 20 and 24. In the given figure, faces 16, 20 and 26 are made flat.

FIG. 5 A depicts how successive addition of blocks 30 from FIG. 4 A, along the x-axis by sliding the blocks along z-axis as explained in FIG. 2A leads to a linear chain of blocks. Each block has faces corresponding face 16 of FIG. 1A as flat.

FIG. 5B shows how addition of more blocks along the y-axis by sliding the blocks along x-axis as explained in FIG. 2B gives rise to a continuous sheet. This continuous sheet is a very important embodiment of the current invention.

FIG. 5C an alternate way of completely locking a linear chain using block 30. Here, an interlock is achieved by sliding the blocks along the z-axis in the same way as explained in 1 A-C and 2 A. The blocks as arranged in 5A are disposed to slide in an out of each other in the direction of the z-axis, so movement is possible in one direction. In the give figure, fastening elements 38 and 38' are inserted between a pair of blocks after creating one pair of through holes per block. The holes pass through the groove and tongue pair involved in the interlock, thus constricting the relative motion of the blocks in the direction of z-axis as well. The holes 42 and 42'are visible on the tongue of block 10'. In this way, a linear chain of blocks is formed which have no degrees of freedom available to them. The blocks can be disassembled only after removal of the fastening element.

FIG. 6 A shows a pair of identical toothed blocks 45 and 45', similar to the block shown in FIG. 3B. Block 45 as shown has a toothed tongue 44 and a toothed groove 46. The toothing is such that sliding of the toothed tongue 44 of block 45 into the toothed groove 46' of block 45' is only possible in one direction. This gives the interlock immense strength opposite to the direction of the sliding motion, such that the structures so formed are permanent in nature. Thus, these blocks are useable in load bearing and retaining walls.

FIG. 6B shows the engagement of the toothed tongue 44 and toothed groove 46' of blocks 45 and 45' respectively. The teeth are configured such that once they are slid in the direction shown by the dotted arrow, they can't move in the opposite direction. The block can however be slid further in the direction of the arrow if no other obstruction is present.

FIG. 7A shows an embodiment of the block of FIG. 3A where the tongues and grooves have rounded faces. The given block can be formed by making the top surface of the block flat in the same manner as in FIG. 4A. The outline is shown to be cuboidal but it can take any shape in general.

FIG. 7B shows an embodiment of the block of FIG. 3C where the tongues and grooves are completely rounded. The given block can be formed by making the top surface of the block flat in the same manner as in FIG. 4 A. The outline is shown to be cuboidal but it can take any shape in general.

FIG. 8A introduces a hollow version of block 10 of FIG. 1A. Material is removed from the block along the z-axis in the shape of a rectangle in the x-y plane, giving rise to the present block 50. Block 50 has a cavity inside it such that front face 16 and back face 22 only contain a small part of the interlocking features i.e. tongue and groove respectively. Interlocking of blocks is still possible on all the surfaces of the block in a manner similar to that explained by FIG. 1 A- C and 2A-C. Thus, a continuous linear and hollow channel can be formed along the z-axis by sliding additional blocks in along the y-axis. Sliding additional blocks along x-axis provides a sheet with several such linear and hollow channels. Further addition of blocks by sliding along the z-axis leads to a matrix of interlocked blocks in x-y plane having hollow channels extending in the direction of the z-axis.

FIG. 8B introduces a hollow version of the block 30 which has a cavity normal to the flat face. In the current block 60, material is removed from the block along the x-axis in the shape of a rectangle in the y-z plane. The hollow block thus formed is similar to block 50 except that it has one of the faces flat. Thus, it is possible to make linear chains or sheets having individual cavities using these blocks. Interlocking features on five of the faces in block 60 are available for interlock. One can choose to use blocks 50 or 60 or any variations thereof by making some faces incapable of interlocking depending upon the number of interlocks required.

An important application of the embodiments shown in FIG. 8A-B is to provide electrical fittings in case of housing and building construction. Thus, instead of inserting pipes to house electrical wires, cables etc. as in conventional constructions we could use the hollow channels formed using block 50. These blocks can be preferably interspersed in a wall made of solid blocks like block 10 and/or 30. Change in direction is achieved by providing blocks with differently configured cavities to provide bends wherever necessary. In a similar way, hollow blocks can be used to provide channels for inserting pipes for water and other utilities. The hollow blocks can be assembled into the wall of solid blocks as explained above. Thus, a continuous cuboidal or cylindrical channel is formed depending upon the shape of the cavities in each block. The water pipes can be inserted into the cavity so that they can be easily removed for servicing and repairs since they are not bound to the individual blocks. Wherever bends are needed, the shape of the block is modified accordingly. In conventional constructions, since the pipes are embedded into the structure, the brick, mortar or concrete around the pipes has to be broken down. The broken sections have to be patched up after the pipe has been repaired or serviced which is highly cumbersome. FIG. 8C shows a block similar to block 50 in FIG. 8A except that instead of being through- hollow, it is made semi-hollow. Thus, block 75 has a cavity but it doesn't extend to the entire length of the block. The same is clearly visible in the section of the block shown in FIG. 8D. This block is useful in some applications like vertical farming, solar cell panels, etc.

In case of vertical farming, the blocks are preferably installed on the exterior of a building, but they can be installed almost anywhere in a building. The blocks can be hollow or semi-hollow so as to hold soil in which small plants or grass can be grown. The placement of blocks on exterior walls is preferable because natural sunlight is available in that case. The blocks can be assembled in many different ways in order to maximize the amount of sunlight captured by the grass, plants, etc. Blocks 50 and 60 may also be used for vertical farming in order to enhance the area available for adding soil.

In case of solar cell panels, the hollow area can be used to house a solar cell or several solar cells depending upon the relative sizes of the cell and the block. Electrical energy is generated on exposure to light and one or more surfaces of the block can have photovoltaic materials. The blocks can be assembled into sheets as explained for block 60. These sheets can be prefabricated, that is to assemble the blocks into sheets similar to the one shown in FIG. 2B. Continuous channels of tongues or grooves are formed on each side of the sheet as explained earlier. Thus, one can slide the sheet into the wall or any other structure in a building having complimentary channels of grooves or tongues. This makes installation of such solar panels very easy and fast. It might be required to provide holes in the solid parts of the block for passing wires to transfer the electrical energy being generated. Moreover, one might use other configurations apart from sheet so as to maximize the amount of solar energy that is captured. Additional equipment may also be installed to further enhance the solar energy captured.

FIG. 16 shows a schematic view of a solar cell panel formed using blocks of the current invention. The photovoltaic material is present inside cavities on the face visible in the figure. Most of the other blocks like block 50 and 60 explained in the preceding paragraphs can also be used in solar cells.

FIG. 9A shows a variation block 10 of FIG. 1A in which all the faces have grooves. It is apparent that one can't get an interlocking structure by using only blocks of this one type. Thus, one can envision a complimentary block similar to block 10 but having only tongues on all the faces. Using the pair of these blocks one can get an interlocking structure wherein each block is surrounded by blocks of the other type in all directions. In the particular case of blocks with significantly cuboidal outline, each block has six complimentary neighbors disposed to interlock with it. FIG. 9B shows a slight variation of the block in FIG. 9A which has one face made flat. Such blocks are useful on the outermost surface of a structure made using the blocks envisioned in FIG. 9A.

FIG. lOA-C illustrate a special hollow block with the purpose of providing support for structures made using hollow blocks as explained in FIG. 8A-C. This block is similar in outline to the block of FIG. 8 A but has internal ribs in the hollow cavity. These ribs provide extra strength in vertical and horizontal directions which is useful to provide support to other blocks on top of them. Thus, these blocks are useable at the bottom of a wall made up of any of the blocks from FIG. 8A-C.

FIG. 1 OA is a perspective view of the present block 80, showing internal ribs 52, 54, 56 and 58 inside the cavity. Tongues and grooves capable of interlocking with complementary features of other blocks are present on four of the faces. FIG. lOB shows a front view of block 80. The outline of the internal ribs is visible as an octagon here, but other shapes are possible as well. The ribs are preferably identical in shape and evenly spaced throughout the length of the cavity. The specific number of the ribs can vary depending on the dimensions of the cavity. FIG. IOC shows a sectional view of the given block along the plane AA' as shown in FIG. 10B. Additional material used in forming the ribs is shown here by hatched lines. The thickness of the ribs and their spacing can be seen to be sufficiently uniform. It must be noted that other shapes, thicknesses, orientations and arrangements of ribs can be used apart from the one discussed in FIG. lOA-C.

FIG. 11A-B illustrate another special hollow block similar to block 80 for providing support to other interlocking blocks of the invention. The block has a hollow cavity running through it as can be seen from its front view in FIG. 11 A and the region surrounding the cavity is made up of honeycomb structures. The thickness to which the honeycomb structures are provided depends upon the strength required. FIG. 1 IB shows a sectional view of the block of FIG. 11 A along the line AA'. The honeycomb structures can be seen in the section pointing out of the plane of the paper. The advantage of using honeycomb structures is that the overall strength to weight ratio of the block increases because honeycomb structures have strong directional compressive strength. Thus, depending upon the requirement, the honeycomb structures can be configured to provide strength in particular directions.

FIG. 12A-C illustrate a swinging door application for hollow blocks similar to the ones explained in the preceding paragraphs. FIG. 12A shows a block 90 similar to the hollow block 60 in FIG. 8B, with the difference of having a door 62 attached to the face devoid of interlocking features. The door is in closed position in the given figure. FIG. 12B and 12C show the block with door 62 open. The door is free to swing about a hinge 64 placed parallel to the y- axis. These blocks can be used in the form of maintenance blocks which can be employed to house electrical fittings and other utilities. Thus, the user has to open the door in order to access the equipment housed therewithin.

FIG. 13A-B illustrate an embodiment of block 10 of FIG. 1A wherein a layer of viscoelastic material 106 is provided. FIG. 13A shows the block 105 covered by a layer of viscoelastic material on all of its faces. FIG. 13B shows a section of the block of FIG. 13 A along the y-z plane and the layer of viscoelastic material can be seen in the shaded region. Sections along the z-x and x-y planes would yield similar sections. The layer of viscoelastic material helps to relieve stresses in the structure. Thus, depending upon the stresses in the structure, the required faces of the block are provided with a layer of viscoelastic material. Usually, stresses are in one or two directions so only the corresponding pairs of planes normal to that direction need to be provided with a layer of viscoelastic material. The layer of viscoelastic material also helps in dampening the vibrations of the blocks in a structure.

FIG. 14A shows a block 110 which is a modification of block 75. Here, a pair of tongue and groove on opposite faces has been reduced in length. Thus, a semi-tongue 15 and a semi-groove 13 are present in block 110. These features are complimentary to each other such that a semi- tongue 15 of block 110 can slide into a semi-groove 13' of block 110' shown in FIG. 14B when oriented properly. Additionally, the face containing the cavity does not have any interlocking features. The advantage achieved is that when a sheet is formed using these blocks, no gaps are present on the face where the hollow portions of all the individual blocks are visible. This is because no interlocking features are present in the immediate proximity of the four visible edges of the blocks present on the outer surfaces. Thus, a continuous sheet exhibiting seamless transition from one block to the other is formed.

Thus, the sheet or screen formed by the blocks as explained above is useful in video display systems because a continuous screen can be formed. Each block can contain liquid crystal display panels, pixellated CRT panels etc. such that the hollow cavity is utilized. Multiple faces can be embedded with video display components if required. The hollow part is used to house the video display components and connecting wires. Holes can be provided in the solid parts of the block to allow wires to pass through and connect with the other components of the video display system.

FIG. 15 is a schematic view of the pixellated display screen formed using interlocking blocks as explained above. The pluralities of rectangles are used to depict pixels on the screen but the screen is flat and smooth as such. FIG. 17A shows an L-shaped block for use in building constructions. The objective of using these blocks is to interlock a pair of adjacent walls in the construction. In the given figure, an reshaped block 100 is shown, which has a pair of grooves at its two distal ends. These grooves can interlock with a pair of complimentary tongues from two structural blocks of two adjacent walls. Also visible is a projection 102 on one of the two faces normal to both the planes containing the grooves. A complimentary depression is found on the face opposite to the one containing the projection. The depression 104' is shown on block 100' of FIG. 17B. Thus, block 100 can be placed on top of block 100' such that the projection sits on the depression and their grooves also sit on top of each other. Thus, the L-shaped blocks can be stacked on top of each other giving rise to a continuous edge for the building. According to the given form of the block in FIG. 17 A- B, each structural block from the pair of walls which interlocks with the block 100 must have a tongue available for interlock. In this way, a strong union of a pair of walls is possible by using these L-shaped blocks.

Variations to the block 100 explained above are possible depending upon the angle between the adjacent walls, which may not always be 90°. It can also be curved instead of L-shaped. The corner block can have tongues in place of grooves or both a tongue and a groove. Other shapes of the mating tongue-groove can be envisioned based on the criteria explained earlier. Other shapes for the projection 102 and depression 104 can also be used.

FIG. 18A-D show different types of interlocking blocks available for making pillars. The blocks are substantially cylindrical in shape with a plurality of tongues and/or grooves evenly spaced on the curved surface and they extend along the length of the cylindrical blocks. FIG.18A shows a block 120 with four lateral tongues placed evenly on the outer curved surface. The given block 120 has a projection 122 and depression 124 on the two faces normal to the curved surface of the block. FIG. 18B shows an identical block 120' wherein the depression 124' is visible and a projection 122' is present on the opposite face that isn't visible. The depressions and projections are of similar sizes to allow for a tight fit. Thus, each block has a projection on one face and depression on the opposite face, thereby rendering it interlockable with one block on top and another block below it. Blocks 120 and 120' can be interlocked by sliding the blocks along the axial direction such that projection 122 and depression 124' superimpose. In this way, the pillar can be extended to a desired height by stacking numerous superposable blocks. Thus, very long pillars can be formed without using very long bars or pillars, thereby simplifying the material handling and construction work required.

FIG. 18C and 18D show alternative forms for block 120 with four lateral grooves and two tongue-groove pairs respectively. The projection and depression have not been shown in FIG. 18C-D for the sake of simplicity. Thus, it must be noted that the blocks can have any number of tongues and/or grooves placed in any order depending upon the application and are not restricted to the figures provided.

FIG. 19A shows a ring or hollow cylindrical type of block 150 which has grooves on its inner curved surface that are complimentary to the tongues of the block 120 of FIG. 18 A. The inner diameter of the ring 150 is approximately the same as the outer diameter of block 120. These rings can slide along the axis of the block 120 or pillar made therefrom, so that the tongue of the pillar gets engaged with the grooves of the rings. FIG. 19B-C show two views of a strong and substantially cylindrical pillar formed in this manner. However, the outer surface of the rings is free to take other shapes like square, hexagon etc. Furthermore, the thickness and length of the rings may also vary depending upon the requirement. The blocks of FIG. 18C and FIG. 18D ca be used to form pillars in a similar manner using rings dimensioned in accordance with ring 150 and having the corresponding complementary tongues and/or grooves. The rings provide resistance to lateral forces and some compressive strength as well. This is particularly useful for the purpose of earthquake or wind engineering of columns.

In another usage, these interlocking blocks can be used to form concentric pillars. For instance, if the ring or hollow cylindrical type of block 150 has tongues and/or grooves on the outer curved surface too, then another set of rings having complimentary features can further interlock with it. The inner diameter of this additional set of rings will be roughly equal to the outer diameter of the first set of rings. Several sets of rings can be added as long as they satisfy the condition that its inner diameter equals the outer diameter of the preceding block/ring and external diameter equals the inner diameter of the succeeding ring. The outermost ring will preferably be shaped similar to ring 150 because there is no need to provide an interlocking feature (tongue or groove) on the outermost surface. The diameter of the pillar can thus be extended to a desired size by adding more concentric rings in the same manner. This application is also useful for creating large diameter pillars without having to transport and construct very large and bulky bars or pillars.

FIG. 20A-B show a pair of identical blocks for construction of pillars. FIG. 20A shows a block 160 with one solid section 162, comprising four grooves distributed on its curved surface and extending throughout its complete length. This section is similar to the block of FIG. 18B. A second, longer section of the block is in the form of a hollow cylinder 164 with tongues on the inner curved surface. The two sections are so configured that the tongues of the solid section of one block cart slide into the grooves of the hollow section of another block when the blocks are placed coaxially. Thus, it is possible to interlock the block 160' from FIG. 20B with the block 160 of FIG. 20 A by interlocking the hollow 164 part of block 160 with the solid part 162' of block 160' or vice versa. Several such blocks can be interlocked in a similar way so as to form a long pillar.

FIG. 21 A, 21 B and 21 C show blocks in the form of hollow cylinders and having tongues and/or grooves on the outer curved surface like the blocks shown in FIG. 18 A, C and D respectively. The blocks in the given figures are useable in pipes. The interlocking features viz. tongues and grooves are utilized to join sections of similar pipes or join a pair of pipes with different diameters. The manner in which this can be achieved is explained in the following figures.

FIG. 22A-C show how interlock is achieved between a pair of pipes having the same internal diameter. The pipe 200 of FIG. 22A is made up of two parts. The first portion which constitutes most of the length of the pipe is a hollow cylinder with tongues on the inner curved surface as can be seen in the left part of FIG. 22A. The figure is showing only a part of the length of the pipe so that the tongues extending along the length are visible. The tongues are arranged symmetrically on the inner curved surface in the given figure but it is not an essential requirement. The second portion of the pipe shown on the right in FIG. 22A is a connector 202 in the form of a hollow cylinder with grooves on both the inner and outer curved surfaces. The outer diameter of the second portion is roughly equal to the inner diameter of the first portion. FIG. 22B shows another pipe 200' which is similar to pipe 200 of FIG. 22A. It is rotated suitably so that the internal profile of the second portion is clearly visible. Thus, pipes 200 and 200' when placed coaxially in a superposable manner can be slid into each other along the axial direction. The tongues of the first portion of pipe 200 get engaged with the grooves of second portion 202' of pipe 200'. FIG. 22C shows a sectional view of the two pipes 200 and 200' interlocked together. The internal profile of the pipes and the continuity between them at the planes of the interlock is visible in the figure. Following the same procedure, a number of such pipes can be connected irrespective of the length of the first portion of each pipe. One could further modify this pipe so that the inner surface where the flow takes place is a hollow cylinder. Thus, the pipe formed by assembling several such pipes is substantially cylindrical at the inner surface.

FIG. 23A-B show a pipe similar to the one of FIG. 22A-B where the location of tongues and grooves has been interchanged. Thus, the first portion now has tongues on the inner curved surface and the second portion has grooves on the outer and inner curved surfaces. The method of connecting the pipes remains the same as explained above.

Pipes with dissimilar diameters but having features similar to FIG. 22 and 23 can be used to join pipes with dissimilar diameters as well. The only condition is that the outer diameter of the smaller diameter pipe discounting tongues/grooves should be roughly equal to the inner diameter of the larger diameter pipe discounting grooves/tongues. In other words, the inner curved surface of the larger diameter pipe should be complimentary to the outer curved surface of the smaller diameter pipe. The pipes can be slid into each other but can't move in any other directions. Thus a strong union of pipes with dissimilar cross section is achieved.

Further applications of the blocks of the current invention are explained hereafter. One may choose any appropriate embodiment of the invention for use in the following applications.

An important application of the embodiments of the invention explained above is that they can be implemented in the form of pre-fabricated structures. What this implies is that the blocks are not assembled one by one at the site but assembled into convenient forms like sheets or linear chains at any convenient location. Thus, a lot of time is saved since the structure isn't assembled block by block at the site. For instance, the solar panels can be assembled beforehand so that they have to be just slid into the complimentary features at the installation site. An important application of blocks 10 and 30 is in mass produced houses. These building blocks can form structures in almost any shape, so a complete house can be constructed faster than using conventional brick and mortar. The interlocking pillars which may be used to provide support are explained in a separate embodiment in FIG.18, 19 and 20. Thus, mass production of identical or similar houses is possible once the components of walls, windows, roof, arches, pillars, etc. are prefabricated and a sequence to assemble them is established. Another advantage is that by applying the reverse sequence, the blocks can be disassembled. The houses thus formed using the blocks of the present invention are very strong, earthquake resistant and resistant to high winds. The blocks can be made fire proof, water proof, thermally insulating, electrically insulating, transparent etc. depending upon the part of the construction in which they are used. For providing electrical fittings and piping the hollow blocks can be used and assembled as per the requirements of the building as explained earlier.

Another useful application of the blocks discussed is in embedded electronics. The blocks contain a complete or a portion of an electronic/electrical circuit embedded onto any number of faces. The block may have connectors on any of its surfaces if it contains only a portion of a circuit. If the adjacent blocks contain the remainder of the circuit, they are connected accordingly. An example of the same is shown in FIG. 24A and 24B which show a face of a block having electronic components and electronic circuits respectively. It is not preferable to have interlocking features on a face having electronic circuit, components, etc. In some cases it would be preferable to use hollow blocks and place hardware components in the hollow area. The components can be integrated into circuits present on the external faces by connecting them accordingly. In some cases, it might be necessary to remove heat from the circuits and hardware. Hollow blocks can be provided in that case to provide cavities to house equipment or provide flow channels for heat removal using any of the several known techniques like fans, heat sinks, liquid coolants etc. Hollow channels can be formed to house wires as explained already. The circuits can also comprise devices like microprocessors, magnetic memory, actuators, sensors and other such devices requiring electrical energy to function.

Thus, depending upon the requirement, one may choose a particular embodiment of the invention. Upon this choice of block, the required number of faces can be chosen to contain electrical or electronic circuitry based upon the function of the circuit and the placement of the block. The circuit can be embedded onto the surfaces using manufacturing methods such as etching, lithography etc. which are used in case of wafer processing. After choosing a suitable process, the circuit can be fabricated permanently into the surface of the block. Newer methods in development such as 3D printing can also be used to directly print the circuit onto the required surfaces of the block.

The block can be made of many materials to suit the particular application. For electronic/ microelectronic circuitry, the block or particular surfaces can be made of base materials as is used in wafer foundry to manufacture semiconductors. Similarly for large appliances, the block can be manufactured using stronger metals or may even have multi-layered surfaces where the inner layers can house the circuitry and the outer layers can offer strength and bear the mechanical parts of the appliance. In case of memory devices, the block can also be constructed out of magnetic materials so the entire block can function as a hard drive.

Due to the variety of the blocks and the vast number of uses, a plurality of raw materials can be used and thus a number of manufacturing methods can be utilized for manufacturing interlocking blocks according to the present invention. Raw materials used to manufacture the Interlocking blocks depend upon the usage of the block. As an example of variation due to desired properties, in case of building construction, blocks at the lower end of a structure are required to have high tensile strength and load bearing capacity. Therefore stronger materials like steels, carbon fiber etc. should be considered. On the other hand, blocks on the higher end of a structure should be as lightweight as possible. Thus, aluminum and other similar materials would be useful.

Also the structure and shape of the block have a role in deciding the material used for production. Blocks requiring high load bearing capacity most likely be made solid and not hollow. This allows for lower strength materials to be the raw material used in the manufacture of these blocks so that the other properties which these materials may provide can be utilized. Another consideration would be the chemical and physical properties required of the block. Blocks used for heat exchange would need to be heat conducting and therefore would require materials with similar properties. Electrically insulating blocks carrying live wires may need materials which are good electrical insulators. Blocks for use in video display can be made by injection molding using plastics having the desired optical properties.

Also the most convenient method of manufacture for a given shape and size of block is an important factor. As an example, a hollow block would be most efficiently manufactured by bending the material to the desired shape and thus requires materials that bend easily while solid blocks are most conveniently manufactured by casting.

The processes used to manufacture the interlocking blocks are dependent on the material of manufacture, the shape and structure of the material as well as the process economics. Ideally all manufacturing methods should be considered while deciding and the merits and demerits of each should be listed. Once this has been done, the process having the most economic efficiency over both the long and short term for the desired quality should be adopted to manufacture the product.

The invention is not limited to the embodiments which have been described and illustrated by way of example and numerous modifications and variations can be proposed without departing from the scope of the appended claims.