This invention relates to prefabricated interlocking concrete blocks.
Interlocking concrete blocks are used for many outdoor construction applications, one of the most common being the construction of retaining walls. Interlocking concrete blocks are thus designed for durability, stability and aesthetic appeal.
One of the ways that aesthetic appeal is imparted to a structure formed from interlocking concrete blocks is to make the exposed face look as much as possible like natural stone. Conventionally this is accomplished by casting concrete blocks in a mold, with the exposed face of one block joined to the exposed face of another block, and breaking the blocks apart along a score line. This results in an essentially random topography on each exposed face of the block pair, which produces a natural ‘look and feel’. An example of a conventionally-formed interlocking concrete block is illustrated in
For example,
The steps in the prior art forming process are illustrated in
There are disadvantages to this manufacturing method. While the (complementary) topographies produced on the exposed faces by breaking the blocks apart looks natural, using this manufacturing method the manufacturer has no control over the final appearance of the exposed face of the block because the fracturing occurs randomly. This limits the profile of the exposed face, and occasionally blocks must be rejected because of over-breakage resulting in the exposed face having a damaged appearance. Also, the height of the concrete blocks is determined by the stroke of the press head, which is a moving part, and since the length of each stroke of the press head may be slightly different there is a commensurate variation in the heights of concrete blocks cast at different times. Furthermore, if a colour other than natural concrete is desired on the exposed face, the colour must be mixed into the entire volume of concrete so that the exposed face provides a uniform colour, which given the cost of some dyes can be very expensive.
One or more of the embodiments of the invention addresses one or more of these disadvantages. While embodiments of the invention are described in detail below, it will be appreciated that not every advantage of the present invention necessarily applies to every embodiment described or claimed herein.
In drawings which illustrate an embodiment of the invention by way of example only:
The present invention provides a mold for and method of manufacturing an interlocking concrete block 20 which has an exposed face to which fully controllable custom textures and profiles can be applied with a press head, in some embodiments without removing the blocks 20 from the mold box. The exposed faces of the blocks 20 can also be coloured as desired, using a minimal amount of expensive concrete pigment in a face coat which can be as little as 10-15 mm thick. The height tolerance of each block 20 is determined by sturdy, fixed structures within the mold itself, rather than by a moving press head as in the prior art technique described above, and is therefore perfect so each block is substantially identical in height with all other blocks cast in the same mold. This is a major benefit for ease of installation compared to prior art systems. By changing the orientation of the blocks 20 within the mold, particularly with the exposed face 28 facing upwardly, the potential for changing the aesthetics of the exposed block face 28 is significantly increased. In order to do this, two main technological advances over the prior art have been employed:
The invention accomplishes this by providing, in the preferred embodiment, a mold 30 in which the interlocking concrete blocks are cast in an orientation such that their exposed faces 28 are at the top of the mold 30. The blocks 20 are thus oriented such that the top surface 22 of one block 20 is adjacent to the bottom surface 24 of the block 20 beside it (or the wall 34 of the mold box 32). The mold box 32 for a typical block configuration is thus deeper than a prior art mold box 12, but commensurately smaller side-to-side so the footprint required for the casting process is reduced. Thus, interlocking concrete blocks 20 can be manufactured according to the method of the invention with a higher throughput for the same amount of floor space.
As noted above, providing the exposed faces 28 of the interlocking concrete blocks 20 at the top of the mold 30 also allows for the application of a surface coat of face mix or another suitable, durable coating material to be applied while the blocks 20 are still in the mold 30. The exposed faces 28 may be coloured as desired without having to colour the concrete used for the body of the interlocking concrete block 20, and/or formed to any desired texture or profile.
The invention thus provides a mold for manufacturing at least one interlocking concrete block, the at least one block having a top surface having a transverse profile comprising at least one interlocking structure projecting from or recessed into the top surface, and a bottom surface having a transverse profile comprising at least one complementary interlocking structure projecting from or recessed into the bottom surface, the mold comprising a mold box, comprising two side walls joined to end walls to define a mold cavity, a top face, and a substantially open bottom face, and top insert members configured to define a space between adjacent blocks or a space between a block and a side of the mold box, extending between the end walls of the box substantially from the top face into the mold cavity, for forming a portion of the transverse profile of the top surface of one block or a portion of the transverse profile of the bottom surface of an adjacent block or both, and a removable draw plate for closing the bottom of the mold box, comprising a generally planar floor, and bottom insert members configured to define a space between adjacent blocks, or a space between a block and a side of the mold box, extending between the end walls and projecting from the floor into the mold cavity, for forming a remaining portion of the transverse profile of the top surface of one block or a remaining portion of the transverse profile of the bottom surface of an adjacent block, or both.
The invention further provides a method of manufacturing a plurality of interlocking concrete blocks each having a top surface having a transverse profile comprising at least one interlocking structure projecting from or recessed into the top surface and a bottom surface having a transverse profile comprising at least one complementary interlocking structure projecting from or recessed into the bottom surface, in a mold comprising a mold box comprising two side walls joined to end walls to define a mold cavity, a top face, and a substantially open bottom face, top insert members configured to define a space between adjacent blocks or a space between a block and a side of the mold box extending between the end walls of the box substantially from the top face into the mold cavity for forming an upper portion of the transverse profile of the top surface of one block or an upper portion of the transverse profile of the bottom surface of an adjacent block or both, and a draw plate comprising a generally planar floor and bottom insert members configured to define a space between adjacent blocks or a space between a block and a side of the mold box extending between the end walls and projecting from the floor into a mold cavity, for forming a remaining portion of the transverse profile of the top surface of one block or a remaining portion of the transverse profile of the bottom surface of an adjacent block, or both, comprising the steps of: a. fitting the mold box to the draw plate such that the bottom insert members are received into openings in the end walls of the mold box; b. feeding concrete into the mold cavity; c. consolidating the concrete; d. in any order: i. sliding the draw plate out of the mold in a lateral direction; and ii. removing the formed blocks from the mold box.
The projecting rib 22a on the top 22 of the block 20 extends laterally (i.e. in the end-to-end direction), and the recess 24a complementary to the rib 22a also extends laterally, providing a “tongue and groove interlock” which prevents one block 20 from shifting transversely relative to the block 20 immediately above or beneath in the structure, as best seen in
In the preferred embodiment of the invention, the blocks 20 are oriented in the mold 30 such that the exposed face 28 of each block 20, defined herein as the face of the block 20 that is intended to be visible in the finished structure (for example a retaining wall), is disposed in a plane generally parallel to the top face 40 of the mold 30, preferably flush with the top of the mold 30.
The mold 30 comprises a mold box 32, comprising two side walls 34 joined to two end walls 36 to define a mold cavity 38. The bottom face 50 of the mold box 32, best seen in
Top insert members 42 are configured to define a space between adjacent blocks 20, and top insert members 52, 54 are configured to define a space between blocks 20 disposed at the sides of the mold 30 and the respective side walls 34. Top insert members 42, 52 and 54 extend between the end walls 36 of the mold box 32, substantially from the top face 40 (i.e. generally flush with the top of the mold box 32) into the mold cavity 38.
The top insert members 42 are configured to form an upper portion of the transverse profile of the top surface 22 of one block 20 and an upper portion of the transverse profile of the bottom surface 24 of an adjacent block 20 in the mold 30. The top insert members 42 are accordingly provided on one side 42a with a profile that is a ‘negative’ of the transverse profile of a portion of the bottom surface 24 of the block 20; and on the other side 42b with a profile that is a ‘negative’ of the transverse profile of a portion of the top surface 22 of the block 20. In the embodiment shown, for example, the top insert members 42 are provided on side 42a with a profile complementary to the transverse profile of the portion of the bottom surface 24 of the block 20 extending from the exposed face 28 up to but not including the recess 24a. The other side 42b is provided with a profile complementary to the transverse profile of the portion of the top surface 22 of the block 20 extending from the exposed face 28 up to and including the outermost surface of the rib 22a.
To complete these portions of the transverse profiles of the blocks 20 that are disposed along the sides 34 of the mold box 32, top inserts 52, 54 are provided defining a space between a block 20 and each side of the mold box 32. The insert 52 is configured with the same complementary profile as the side 42a of the insert member 42 and extends between the ends 36 of the mold box 32 along one side 34, and thus forms an upper portion of the transverse profile of the bottom surface 24 of the block 20 disposed along the side of the mold 30 at the left in
The mold floor is formed by a removable draw plate 60, for closing the bottom face 50 of the mold box 32 and containing the concrete during casting. The draw plate 60 comprises a generally planar floor 62 which spans at least the length and width of the bottom 50 of the mold box 32, to thereby seal the bottom of the mold cavity 38 sufficiently to prevent concrete from seeping out of the mold 30 under the force of gravity and compression/consolidation. Extending between the end walls 36 of the mold box 32 and projecting from the planar floor 62 into the mold cavity 38 (when the draw plate 60 is in position for casting) are bottom insert members 64 and 66. Bottom insert members 64 are configured to define a space between adjacent blocks 20, and between blocks 20 disposed at the sides of the mold 30 and the respective side wall 34, for forming the remaining portion of the transverse profile of the bottom surface 24 of a block 20, in the embodiment shown extending from the rear face 29 of the block 20 up to and including the recess 24a. Bottom insert members 66 are configured to define a space between adjacent blocks for forming the remaining portion of the transverse profile of the top surface 22 of a block 20, in the embodiment shown extending from the rear face 29 of the block 20 up to but not including the rib 22a. Thus, bottom insert members 64 and 66 form the remainder of the transverse profiles of the top and bottom surfaces 22, 24 of the interlocking block 24, as best seen in
At least one end wall 36 of the mold box 32 provides openings 64a, 66a into which the bottom insert members 64, 66 are respectively received. Preferably the openings 64a, 66a closely match the profiles of the bottom insert members 64, 66, respectively, providing a seal that substantially prevents concrete from seeping out of the openings 64, 66 when the draw plate 60 is in position in the mold 30. It may in some embodiments be advantageous to provide openings 64a, 66a in both end walls 36, as in the embodiment shown (best seen in
As shown in
In the preferred embodiment openings 64a, 66a are provided in both end walls 36 of the mold box 32, as shown in
In a still further alternative (not shown), the openings 64a in the end walls 36 can be formed to match the profile of the insert members 64, including the undercut 64a, and the concrete will be retained within the mold cavity 38 because of the close fit of the openings 64a around the insert members 64. However, in this embodiment the draw plate 60 must be inserted horizontally into the mold box 32, rather than the mold box 32 being lowered vertically onto the draw plate 60, which makes automation more complex.
It will be appreciated that the insert members 42, 54, 56, 64 and 66 extend fully between the end walls 36 of the mold box 32 because the ribs 22a and recesses 24a extend fully end-to-end across the blocks 20. In embodiments where the interlocking structures do not extend fully end-to-end across the blocks 20, the insert members 42, 54, 56, 64 and 66 will only have the length necessary to form the interlocking structures.
The press head 15 is retracted, as shown in
The mold box 32 is then lifted off of the newly formed blocks 20, as shown in
It is advantageous to slide the draw plate 60 out from under the newly formed blocks 20 while the mold box 32 is still in position. Alternatively, the mold box 32 can be lifted first and the blocks 20 held in position by other means as the draw plate 60 is drawn out from underneath the blocks.
Finally, as shown in
The components of the mold 30 would typically be formed from steel or any other suitable material. The embodiment illustrated is dimensioned to cast three concrete blocks 20, however the mold 30 can be designed to cast fewer or more concrete blocks 20 as desired, the components of the mold 30 being provided with thicknesses suitable for withstanding the weight of the concrete without deforming. It will be appreciated that since the components of the mold box 32 and draw plate 60 combine to form parallel surfaces, increased accuracy of mold construction and manufacturing may be required.
It will be appreciated that although the blocks 20 are illustrated as oriented in the same direction in the mold 30, because of the versatility in providing profiles on the inserts 42, 52, 54, 64, 66, the blocks 20 can be oriented in the mold 30 in different directions, for example some facing rib-to-rib and others oriented rib-to-recess as shown.
A mold and method for manufacturing interlocking concrete blocks has been described. In an embodiment, the mold comprises a mold box, comprising two side walls joined to end walls to define a mold cavity, a top face, and a substantially open bottom face. Top insert members are configured to define a space between adjacent blocks, for forming a portion of the transverse profile of the top surface of one block or a portion of the transverse profile of the bottom surface of an adjacent block, or both. A removable draw plate for closing the bottom of the mold box comprises a generally planar floor and bottom insert members configured to define a space between adjacent blocks, for forming a remaining portion of the transverse profile of the top surface of one block or a remaining portion of the transverse profile of the bottom surface of an adjacent block, or both. Thus, inserts within the mold box and vertical projections from the draw plate combine to form the top and bottom surfaces of the block, making the draw plate a more important component in the formation of both the positive and negative structures of the block.
Various embodiments of the present invention having been thus described in detail by way of example, it will be apparent to those skilled in the art that variations and modifications may be made without departing from the invention. For example, although less advantageous than the preferred embodiments, the blocks 20 could be formed in the mold with their exposed faces 28 at the bottom of the mold while still providing some advantages of the invention. The invention includes all such variations and modifications as fall within the scope of the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
4023767 | Fontana | May 1977 | A |
4335549 | Dean, Jr. | Jun 1982 | A |
4660344 | Gaudelli | Apr 1987 | A |
8765044 | Ness | Jul 2014 | B2 |
20030126821 | Scherer | Jul 2003 | A1 |
20040218985 | Klettenberg | Nov 2004 | A1 |
20080258340 | Klettenberg | Oct 2008 | A1 |
20080277561 | MacDonald | Nov 2008 | A1 |
Number | Date | Country | |
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20150151450 A1 | Jun 2015 | US |