| Molds and processes that permit high-speed, mass | | | | such a concrete block suitable for use as a retaining |
| production of retaining wall blocks having patterned | | | | wall block, andthe common method for producing |
| or other processed front faces, as well as retaining | | | | such a block in a high speed, automated concrete |
| wall blocks formed by such processes. The invention | | | | block plant. |
| permits the front face of the block to be impressed | | | | There is demand for a pre-formed concrete unit, |
| with a pattern or otherwise directly processed, to | | | | particularly a retaining wall block with converging side |
| allow the formation of pre-determined concrete brick | | | | walls and/or an integral locator and shear flange |
| machine front faces, while at the same time | | | | formed on the top and/or bottom face, and having a |
| facilitating high-speed, high-volume production of | | | | more natural appearing face than isachievable by the |
| blocks. | | | | splitting process described in U.S. Pat. No. 5,827,015, |
| A mirror image of the desired pattern can be created | | | | or by the splitting process described in U.S. Pat. No. |
| on a stripper shoe by selecting a desired | | | | 6,321,740, which is also incorporated herein by |
| three-dimensional surface from a naturally occurring | | | | reference. In particular, there is a demand for |
| or man made object and digitally scanning the | | | | processes and toolingthat will create such blocks with |
| selected three-dimensional pattern to create scanned | | | | such faces in high-speed, automated fashion on the |
| data. The scanned data can then be used to machine | | | | type of equipment commonly available in a concrete |
| a face of the stripper shoe that is the mirror image | | | | block or concrete paver plant. |
| of the selected pattern. | | | | The invention relates to molds and processes that |
| A method of making a concrete block having a three | | | | permit high speed, mass production of concrete units, |
| dimensional patterned face, comprising the steps of: | | | | and, in particular, retaining wall blocks. These molds |
| selecting a three-dimensional pattern of one or more | | | | and processes can be used to create relatively simple |
| existingobjects; digitally scanning the selected | | | | decorative front faces on suchblocks, similar to the |
| three-dimensional pattern to create scanned data in | | | | split faces described in U.S. Pat. No. 5,827,015. These |
| XYZ coordinates that is representative of the | | | | molds and processes can also be used to create |
| selected three-dimensional pattern; creating from the | | | | more complex front faces on such blocks, similar to |
| scanned data in the XYZ coordinates a digital data | | | | the split and distressed faces produced by |
| set thatis representative of a desired three | | | | conventional tumbling orhammermill processing, or by |
| dimensional patterned face of the concrete block | | | | the process described in U.S. Pat. No. 6,321,740. |
| based on the scarmed data of the three-dimensional | | | | These molds and processes can also be used to |
| pattern; using the digital data set to create a mold | | | | create unique blocks that have heretofore not been |
| surface with a three-dimensional pattern that is the | | | | available: retaining wall blocks with converging side |
| mirrorimage of the desired three dimensional | | | | walls and/or integrallocator and shear flanges and |
| patterned concrete block face, the three-dimensional | | | | with front faces with significantly more complex |
| pattern on the mold surface having a maximum relief | | | | faces, including faces with significant detail and relief |
| of at least about 0.5 inches; providing a mold having a | | | | not heretofore available in dry cast concrete block |
| plurality of side walls defining a mold cavity, themold | | | | technology. |
| including the mold surface with the mirror image of | | | | In a preferred embodiment, the resulting blocks have |
| the desired three-dimensional pattern concrete block | | | | patterned front faces that simulate natural stone, as |
| face; introducing dry cast concrete into the mold | | | | well as upper and lower faces, a rear face, opposed |
| cavity; compacting the dry cast concrete to form a | | | | converging side faces, and a flange extending below |
| pre-cured concrete block, wherein duringcompaction, | | | | the lower face. Blocks having thisconstruction, when |
| the desired three-dimensional patterned face is | | | | stacked in multiple courses with other similarly |
| imparted to the pre-cured concrete block by the | | | | constructed retaining wall blocks, permits construction |
| mold surface with the mirror image of the desired | | | | of serpentine or curved retaining walls that appear to |
| three dimensional patterned concrete block face; | | | | have been constructed with naturally-occurring, rather |
| discharging the pre-cured concrete block fromthe | | | | than man-made,materials. |
| mold cavity; and curing the pre-cured concrete block. | | | | One aspect of this invention is that a mold made in |
| The invention relates generally to concrete blocks | | | | accordance with the invention is arranged so that the |
| and the manufacture thereof. More specifically, the | | | | portion of the block that will be the front face when |
| invention relates to concrete blocks suitable for use in | | | | the block is laid is facing the open top of the mold |
| landscaping applications, such as retaining walls, and | | | | cavity during the moldingprocess. This orientation |
| manufacturing processes usefulin the production of | | | | permits the front face of the block to be formed by |
| such blocks. | | | | the action of a patterned pressure plate ("stripper |
| Modern, high speed, automated concrete block plants | | | | shoe") in a high-speed, concrete block or paver plant. |
| and concrete paver plants make use of molds that | | | | The stripper shoe can be provided with a very simple |
| are open at the top and bottom. These molds are | | | | pattern, amoderately complex pattern, or a highly |
| mounted in machines which cyclically station a pallet | | | | detailed, three-dimensional pattern with significant |
| below the mold to close the bottom of themold, | | | | relief, simulating naturally occurring stone. Molding the |
| deliver dry cast concrete into the mold through the | | | | block in this orientation also makes the block face |
| open top of the mold, densify and compact the | | | | readily accessible for other processing to affectthe |
| concrete by a combination of vibration and pressure, | | | | appearance of the face, including the application of |
| and strip the mold by a relative vertical movement of | | | | specially-selected aggregate and/or color pigments to |
| the mold and the pallet. | | | | the face. |
| Due to the nature of such plants and the equipment | | | | Another aspect of this invention is that a side wall of |
| used to perform this process, it is difficult to impart a | | | | the mold has an undercut portion adjacent the open |
| natural appearance to the face of a concrete block, | | | | bottom of the mold cavity. This undercut portion |
| particularly if the block needs to include other | | | | cooperates with the pallet that is positioned under |
| features, such as converging sidewalls, and an integral | | | | the mold to form a subcavity of themold. In a |
| locator and shear flange(s) formed on the top and/or | | | | preferred embodiment, this subcavity forms the |
| bottom face of the block. U.S. Pat. No. 5,827,015, | | | | locator and shear flange on the surface of the block |
| which is incorporated herein by reference, discloses | | | | that will be the bottom of the block machine as laid. |