Abstract:
A method of manufacturing retaining wall blocks includes providing a mold and disposing a core in the mold. A dry casting concrete mixture is introduced into the mold around the core. The mixture is compressed with a movable shoe to form a casting comprising two retaining wall blocks joined together. The core is removed to form an aperture through the casting, the aperture defined by a wall surface. The formed casting is released from the mold and then split along a plane extending through the aperture to define two retaining wall blocks such that each block, on an outer surface thereof, has a groove defined by a portion of the wall surface of the aperture. Each groove can divide the front surface of the block into two asymmetric panels.

Description:
RELATED APPLICATION  
       [0001]     This application is a continuation of application Ser. No. 10/836,512 filed Apr. 30, 2004, which is hereby fully incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Retaining walls are widely used in a variety of landscaping applications. Typically, they are used to maximize or create level areas and to reduce erosion and slumping. They may also be used in a purely decorative manner. In the past, retaining wall construction was labor intensive and often required the skills of trained trades people such as masons and carpenters. More recently, retaining wall construction has become significantly simplified with the introduction of self-aligning, modular, molded blocks of concrete that may be stacked in courses without the use of mortar or extensive training. With these types of blocks, it is possible to erect a retaining wall quickly and economically, and the finished product creates the impression and appearance of a conventional block and mortar retaining wall.  
         [0003]     The facings of such blocks are typically formed with surfaces that create the impression that the block as been finished or split away from a larger body of stone. The facings can have split surfaces, faceted surfaces, smooth surfaces, planar surfaces, or be combinations thereof. Sometimes vertical channels are included on the facing to give the impression that there are two stones adjacent each other in a single course. However, a drawback with such channels is that they are usually clearly identifiable as such, especially when compared to vertical joints that are formed between adjacent blocks.  
         [0004]     Another drawback with such blocks, is that only certain types of constructions are possible, such as vertically aligned walls or walls that may be rearwardly offset. In addition, such blocks are usually constrained to the particular pattern in which they may be arranged, for example, a running bond. Such prior art blocks are usually not available in different sizes nor is it possible to subdivide such blocks with consistent results.  
       FIELD OF THE INVENTION  
       [0005]     This invention relates generally to the construction of walls used in landscaping applications. More particularly, the present invention relates to a masonry block that can be used to build retaining walls.  
       SUMMARY OF THE INVENTION  
       [0006]     A method of manufacturing retaining wall blocks includes providing a mold and disposing a core in the mold. A dry casting concrete mixture is introduced into the mold around the core. The mixture is compressed with a movable shoe to form a casting comprising two retaining wall blocks joined together. The core is removed to form an aperture through the casting, the aperture defined by a wall surface. The formed casting is released from the mold and then split along a plane extending through the aperture to define two retaining wall blocks such that each block, on an outer surface thereof, has a groove defined by a portion of the wall surface of the aperture. Each groove can divide the front surface of the block into two asymmetric panels.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a front, perspective view of one embodiment of a block;  
         [0008]      FIG. 2  is a side elevational, cross-sectional view of the block of  FIG. 1 ;  
         [0009]      FIG. 3  is a rear, perspective view of the block of  FIG. 1 ;  
         [0010]      FIG. 4  is a bottom plan view of the block of  FIG. 1 ;  
         [0011]      FIG. 5  is a partial, exploded, perspective view of the casting and the associated mold, divider plate, and core used to form it;  
         [0012]      FIG. 6  is a top plan view of a casting of  FIG. 5  that has been removed from its mold, and before it has been split into two blocks;  
         [0013]      FIG. 7  is a partial, cross-sectional, side view of a preferred embodiment of a core used in the fabrication of the block of the preferred embodiment;  
         [0014]      FIG. 8  is a bottom plan view of the core of  FIG. 7 ;  
         [0015]      FIG. 9  is a front, perspective, exploded view of the block of  FIG. 1 , after it has been split;  
         [0016]      FIG. 10  is bottom plan view of an alternative embodiment of a block;  
         [0017]      FIG. 11  is a side elevational, cross-sectional view of the block of  FIG. 10 ;  
         [0018]      FIG. 12  is a bottom plan view of another embodiment of a block;  
         [0019]      FIG. 13  is a side elevational, cross-sectional view of the block of  FIG. 12 ;  
         [0020]      FIG. 14  is a front, perspective view of another embodiment of a block;  
         [0021]      FIG. 15  is a side elevational, cross-sectional view of the block of  FIG. 14 ;  
         [0022]      FIG. 16  is a rear perspective view of the block of  FIG. 14 ;  
         [0023]      FIG. 17  is a front elevational view of a structure that may be formed by the blocks disclosed; and,  
         [0024]      FIG. 18  side elevational view of a structure that may be formed by the blocks disclosed. 
     
    
     DETAILED DESCRIPTION  
       [0025]     Turning to the figures wherein like parts are designated with like numerals throughout several views, the directions vertical and horizontal as used herein are made with reference to blocks in their normal position of use, eg. as in a wall, and wherein the dimensions of height, width, and depth correspond to the x, y, and z axes in a three dimensional coordinate system. With reference to  FIG. 1 a  preferred embodiment of a wall block  10  comprising a top surface  12 , a bottom surface  14 , a front surface  16 , a rear surface  18  (see,  FIGS. 2, 3 , and  4 ), and first and second side surfaces  20 ,  22 , respectively, is disclosed. The front surface  16 , as depicted, includes a first groove  30  that extends vertically between the top and bottom surfaces,  12  and  14 . The first groove  30  simulates a joint that is normally formed between the sides of adjacent blocks in a course of blocks. In forming the simulated joint, the first groove  30  divides the front surface or facing into two panels  32  and  34 .  
         [0026]     The block  10  also comprises a weakened section  50 , indicated generally to be an area bounded by dashed lines  52 ,  54 , which extends between the front surface  16  and the rear surface  18  along the depth (z-axis) of the block. As shown, the weakened section  50  includes a generally L-shaped opening  80  that extends along a portion of the top surface  12 . In this preferred embodiment, the opening  80  of the weakened section  50  is formed by a first segment  82  and a second segment  84 , which are in communication with each other, and which have longitudinal axes  83  and  85  that are angled with respect to each other (see,  FIG. 4 ). The first segment  82  is generally defined by walls  86 ,  88 ,  90 , and the second segment  84  is defined by walls  92 ,  94 , and  96 . It will be appreciated that the first and second segments need not be in communication with each other, and may be separate and distinct if desired. Moreover, it is understood that the opening could comprise more or less than two segments, which also may be separate and distinct.  
         [0027]     A cross-sectional, side elevational view of the weakened section  50  is depicted in  FIG. 2 . Starting from the right side and moving towards the left, a portion of the weakened section includes the first groove  30  that begins at the front surface  16  and extends into the block body towards the rear surface  18  along the depth (z-axis) of the block. To the left of the first groove  30  is a web  56 , whose rearward extent is defined by a wall  92  of the second segment  84 . Continuing towards the left, wall  86  of the first segment  82  extends rearwardly until it reaches a second web  58 , whose rear extent is defined by a second groove  40 , and whose lower extent of the web is defined by an upper wall  49  of a notch  46  (see also,  FIG. 3 ).  
         [0028]     With reference to  FIG. 3 , the rear surface  18  of block  10  includes a second groove  40  that extends between the top surface of the block  12  and the upper wall  49  of notch  46 . As with the first groove on the front surface, the second groove  40  divides the back surface  18  into two panels  42  and  44 . And, as with the first groove, the second groove  40  is generally aligned with the opening  80  in splitting juxtaposition with respect thereto. The notch  46 , generally defined by walls  48   a ,  48   b , and  49 , is in communication with opening  80 , although it will be appreciated that they may be separate and distinct if desired. As will be understood, the blocks of this embodiment are configured and arranged so that a structure formed therefrom is able to resist forces exerted against the rear surface of the structure. This is achieved by providing the blocks with stop surfaces and projections.  
         [0029]     As shown in  FIGS. 3 and 4 , stop surfaces  66 ,  68  are located at side surfaces  20 ,  22 , between the front and rear surfaces of the block, while a pair of spaced apart projections  60   a  and  60   b  are located on the bottom surface  14  of the block. Each projection  60   a ,  60   b  includes a contacting surface  62   a ,  62   b , and a non-contacting surface  64   a ,  64   b , respectively. The contacting surfaces  62   a ,  62   b  are configured and arranged to engage the stop surfaces of a vertically adjacent course of blocks. The bottom surface  14  of the block also includes a pair of spaced apart positioning elements  70   a  and  70   b . Each positioning element  70   a ,  70   b  includes a support surface  72   a ,  72   b , respectively, which is configured and arranged to provide stability when a plurality of like blocks are stacked onto a pallet for shipping.  
         [0030]     With reference to  FIGS. 5-8 , fabrication of the above-described embodiment will be discussed. While the block can be formed individually, it is advantageous to form two blocks from a larger casting  8  as shown in  FIGS. 5 and 6 . The casting may be either wet or dry, but dry casting is preferred. Generally, a dry casting is formed by introducing a mixture of cementitious material into a mold box and then compressing the mixture using a movable shoe. After compression, the block is removed from the mold, cured, and prepared for shipping and use. To fabricate blocks that have voids, through holes, hollows, etc., it is a common practice to provide the mold with cores and/or divider plates. The exploded, partial, view of  FIG. 5  depicts the use of a core  100  and a divider plate  103 , which may be attached to a support bar  105 , which in turn may be attached to a mold box M that is positioned on a pallet P. Note that the mold box M and the pallet P are shown in phantom and do not constitute a part of this invention. Also, note that a movable shoe, which is normally used to compress the mixture and remove it from the mold box, has been omitted. After the casting  8  has been removed from the mold in which it was cast, it may be further processed by splitting into two individual blocks.  FIG. 6  shows, in dashed line  7 - 7 , where the casting may be split. Note the aperture  9 , which is intersected by the splitting line. When the casting is split into two blocks, the aperture  9  is transformed into two grooves  30 .  
         [0031]     The aperture  9  is formed by a core  100 , shown in  FIGS. 7 and 8 . As depicted, the core is generally elongated and has a longitudinal axis  101 . Generally, the core  100  comprises a body  102  having a first end  104  and second end  106 , with the core being configured and arrange so that it may modify and manipulate the block as it is being removed from the mold. In this regard, the core may take a variety of different forms and have different surface textures. Preferably, though, the body  102  has a generally polygonal cross-section with a plurality of similarly configured exterior sides. Although the sides are generally elongated and planar, it will be understood that they may assume other configurations without departing from the spirit and scope of the invention. For example, the sides may have an arcuate contour. Preferably, four sides are configured and arranged to form a core having a generally square cross section. However, it will be appreciated that the angles formed by the intersection of two of the sides may form an angle  118  having a range of about 30-150 degrees and the cross section of the core may appear more rhomboid-like.  
         [0032]     Each side of the core may be provided with a textured surface, which is able to produce different surface textures in a block surface. Preferably, the sides may comprise a plurality of channels that are oriented so that they are angled with respect to the direction of removal of a block from a mold. This allows block material within the channels to be worked and redistributed over the surface of a block in churning and repacking motions. As can be seen in  FIG. 7  the sides of the core form roughened portions  36  and  38  in the front surface a block as the core is separated from the block. As will be appreciated, the channels may also be varied cross-sectionally along their length, as well as with respect to each other. In addition, the channels may also vary in depth along their length. Although the channels are generally v-shaped, it is understood that other configurations are possible, for example, a u-shape, a squared notch shape, or a hemispherical shape. It is also understood, that the channels need not all have the same general cross-sectional profile. Thus one channel may be v-shaped and the next channel may be u-shaped, and the next channel may be yet another shape. Alternatively, it is envisioned that the sides of the core may be provided with a series of indentations and/or protrusions that churn, redistribute, and repack block material.  
         [0033]     The core  100  may also include a base  108 , which may be attached to the second end  106 . Generally, the base  108  is configured so that it may also modify and manipulate the block as it is being removed from the mold. The base has at least two tines  120 , 122  that extend in opposite directions from the body  102  of the core  100  by a distance that is sufficient to enable the tines to modify and manipulate the block as it is being removed from the mold. Preferably, each tine is formed by two generally planar walls that form an angle  124  of about 30-150 degrees. And preferably, each tine extends beyond the body of the core by a distance of about ⅛ to about 1 inch (0.57 to 2.54 cm). As will be appreciated, the tines enable the core to form crevices  39  in front surfaces of blocks that create and accentuate shadows, and give the impression that there are two blocks instead of one block.  
         [0034]     A block  510  that has been split into two smaller blocks  510   a  and  510   b  is depicted in  FIG. 9 . As can be seen, block  510   a  includes the front panel  532 , while block  510   b  includes front panel  534 . As will be appreciated each block  510   a  and  510   b  may have a corresponding projection, a positioning element, or both projection and positioning element as the case may be (see, for example,  FIGS. 4, 10  and  15 ). A benefit of having the dual projections and positioning elements is that when a single block is split into two smaller blocks, each block will have the same ability to resist forces exerted against the rear surface of a structure as a whole block. Moreover, the user of such blocks will now be able to construct structures in a myriad of combinations (see, for example,  FIG. 17 ). As will be understood, the blocks need not be split before they are assembled into a structure. They may be split in situ after a structure has been constructed.  
         [0035]     With reference to  FIGS. 10 and 11  an alternative embodiment of a wall block  210  comprising a top surface  212 , a bottom surface  214 , a front surface  216 , a rear surface  218 , and first and second side surfaces  220 ,  222 , respectively, is disclosed. As with the embodiment of  FIG. 1 , the front surface  216 , includes a first groove  230  that extends vertically between the top and bottom surfaces,  212  and  214 , and which simulates a joint that is normally formed between the sides of adjacent blocks. In forming the simulated joint, the first groove  230  separates the front surface or facing into two panels  232  and  234 .  
         [0036]     The block  210  also comprises a weakened section similar to the weakened section  50  of  FIG. 1 . However, for purposes of clarity, the dashed lines that indicate the general boundaries of the weakened section have been omitted, and it will be understood that the weakened section extends between the front surface  216  and the rear surface  218  along the depth (z-axis) of the block. As shown, the weakened section may comprise a generally L-shaped opening  280  that is formed by a first segment  282  and a second segment  284 , which are in communication with each other.  
         [0037]     The weakened section can be more clearly seen in  FIG. 11 , which has been rotated from its normal horizontal orientation to a vertical orientation. Starting from the top and moving towards the bottom, a portion of the weakened section comprises a web  256 , whose forward extent is defined by a wall  292  of the second segment  284 . Continuing down, wall  286  of the first segment  282  extends rearwardly until it reaches a second web  258 , whose forward extent is defined by wall  290  of the first segment  282 . As with the preferred embodiment of  FIG. 1 , the first and second segments  282  and  284  of this embodiment also extend between the top and bottom surfaces  212  and  214 . Continuing down, the lowermost extent of web  258  is defined by a second groove  240 , while the leftmost extent is defined by an upper wall  249  of a notch  246 . The rear surface  218  of block  210  also includes a second groove  240  that forms two panels  242  and  244 , and which extends between the top surface of the block  212  and the upper wall  249  of notch  246 . As will be appreciated notch  246  may be in communication with the first segment  282  of opening  280 , although not necessarily so.  
         [0038]     As can be seen in  FIG. 10 , the bottom surface  214  of this embodiment does not have a pair of spaced apart projections. Rather, the bottom surface  214  of the block includes a pair of spaced apart positioning elements  270   a  and  270   b , which are located adjacent the opposing walls of notch  246 . Each positioning element  270   a ,  270   b  includes a contacting surface  272   a ,  272   b , respectively, with the contacting surfaces configured and arranged to engage the rear surface of a vertically adjacent course of blocks. It will be appreciated that this embodiment enables wall structures having an upwardly receding slope or batter to be constructed. It will also be appreciated that with this embodiment, courses of blocks may not only be arranged in a traditional bonds such as a running bond, they may also be stacked in a generally columnar fashion as well.  
         [0039]     With reference to  FIGS. 12 and 13  another alternative embodiment of a wall block  310  comprising a top surface  312 , a bottom surface  314 , a front surface  316 , a rear surface  318 , and first and second side surfaces  320 ,  322 , respectively, is disclosed. As with the embodiment of  FIG. 1 , the front surface  316 , includes a first groove  330  that extends vertically between the top and bottom surfaces,  312  and  314 , and which simulates a joint that is normally formed between the sides of adjacent blocks. In forming the simulated joint, the first groove  330  separates the front surface or facing into two panels  332  and  334 .  
         [0040]     The block  310  also comprises a weakened section similar to the weakened section  50  of  FIG. 1 . However, for purposes of clarity, the dashed lines that indicate the general boundaries of the weakened section have been omitted, and it will be understood that the weakened section extends between the front surface  316  and the rear surface  318  along the depth (z-axis) of the block. As shown, the weakened section includes a generally L-shaped opening  380  that is formed by a first segment  382  and a second segment  384 , which are in communication with each other.  
         [0041]     The weakened section can be more clearly seen in  FIG. 13 , which has been rotated from its normal horizontal orientation to a vertical orientation. Starting from the top and moving towards the bottom, a portion of the weakened section comprises a web  356 , whose extent is defined by a wall of the second segment  384 . Continuing down, wall  386  of the first segment  382  extends downwardly until it reaches a second web  358 . As with the preferred embodiment of  FIG. 1 , the first and second segments  382  and  384  of this embodiment also extend between the top and bottom surfaces  312  and  314 . Continuing down, the lowermost extent of web  358  is defined by a second groove  340 , while the leftmost extent is defined by an upper wall  349  of a notch  346 . The rear surface  318  of block  310  also includes a second groove  340  that forms two panels  342  and  344 , and which extends between the top surface  312  of the block and the upper wall  349  of notch  346 . As will be appreciated notch  346  may be in communication with the first segment  382  of opening  380 , though not necessarily so.  
         [0042]     As can be seen in  FIG. 13 , the bottom surface  314  of this embodiment does not have a pair of spaced apart positioning elements. Rather, the bottom surface  314  of block  310  includes a pair of spaced apart projections  360   a  and  360   b , which are located adjacent the opposing walls of first segment  382 , and which may also be located adjacent the opposing walls of notch  246  as well. Each projection  360   a ,  360   b  includes a contacting surface  362   a ,  362   b , and a non-contacting surface  364   a ,  364   b , respectively. The contacting surfaces  362   a ,  362   b  are configured and arranged to engage the stop surfaces  366 ,  368  of a vertically adjacent course of blocks. As shown, the distance between the contacting and non-contacting surfaces of the projections can vary from a point spaced from the front surface  316  to the back surface  318 . This variable distance has a range of about 1-8 inches (2.54 to 20.32 cm), which is about 10 to 75 percent of the depth of the block. Examples of the variable distances are shown in dashed lines  361   a  and  361   b . It will be appreciated that the location of the contacting surfaces  362   a  and  362   b  may also be varied along the depth of the block, which would allow the blocks to be arranged in vertical or stepped courses (see,  FIGS. 17 and 18 ).  
         [0043]     With reference to  FIGS. 14-16  an alternative embodiment of a wall block  410  comprising a top surface  412 , a bottom surface  414 , a front surface  416 , a rear surface  418 , and first and second side surfaces  420 ,  422 , having stop surfaces  466 , and  468 , respectively, is disclosed. As with the embodiment of  FIG. 1 , the front surface  416 , includes a first groove  430  that extends vertically between the top and bottom surfaces,  412  and  414 , and which simulates a joint that is normally formed between the sides of adjacent blocks. In forming the simulated joint, the first groove  430  separates the front surface or facing into two panels  432  and  434 .  
         [0044]     The block  410  also comprises a weakened section  450 , indicated generally to be an area within dashed lines  452 ,  454 , and which extends between the front surface  416  and the rear surface  418  along the depth (z-axis) of the block. Like the weakened section of the previously described embodiments, the weakened section  450  of this embodiment is a generally L-shaped opening that extends between the front  416  and rear  418  surfaces along the depth direction or z-axis in a three dimensional coordinate system. In this preferred embodiment, however, the opening does not extend through the top surface  412  of the block. Rather, the opening has a variable vertical extent that is indicated by solid and dashed lines  481  (see,  FIG. 15 ).  
         [0045]     The weakened section  450  can be more clearly seen in  FIG. 15 . Starting from the right side and moving towards the left, a portion of the weakened section includes the groove  430  that begins at the front surface  416  and extends along the depth or z-axis in a three dimensional coordinate system towards the rear surface of the block. At the point of termination of the groove  430  there begins a web  456 , whose extent is defined by a wall of the second segment  484 . Continuing towards the left, wall  486  of the opening extends rearwardly until it reaches a second web  458 . Note, in this embodiment, the opening  480  does not extend to the top surface. Rather, the opening has a vertical extent  481  that is variable in height. Continuing to the left, the rear extent of web  458  is defined by a second groove  440 , while the lower extent is defined by an upper wall  449  of a notch  446 .  
         [0046]     With reference to  FIG. 16 , the rear surface  418  of the block includes a second groove  440  that forms two panels  442  and  444 , and which extends between the top surface  412  of the block and the upper wall  449  of notch  446 . Since the structure of the notch as been described above, it will not be discussed here in detail. The block  410  may also include a pair of spaced apart projections  460   a  and  460   b , a pair of spaced apart positioning elements  470   a  and  470   b , or a combination of projections and positioning elements (see also,  FIG. 15 ). It will be understood that if this embodiment is provided with projections, the primary point of engagement between vertically adjacent blocks will be stop surfaces  466  and  488  of sides surfaces  420  and  422 . It will also be understood that if this embodiment is provided with only positioning elements, the point of engagement between vertically adjacent blocks will be at the rear surface  418  (see, for example,  FIG. 18 ).  
         [0047]     In use, the block may be used to construct a vertical, free standing wall or a retaining wall having an upwardly receding slope, or batter as shown in  FIGS. 17 and 18 , respectively. Generally, each type of structure depicted may be assembled by first laying a first course of blocks to form a base layer. Then, additional courses of blocks are added, preferably by setting the front end of a block on the rear portion of the course below and then sliding the block forwardly along the depth direction (z-axis) until the block comes into engagement with the lower course of blocks. It will be understood that the point of engagement between vertically adjacent blocks will depend upon whether the block is provided with projections or positioning elements.  
         [0048]     After a wall has been constructed, the blocks in the wall may be split into smaller blocks, if desired. This may be accomplished by initiating a fracture along the front groove, which is in splitting juxtaposition relative to the weakened section. As one will appreciate, the fracture will travel along the weakened section of the block towards the rear surface. Because the blocks in the structure are usually constrained by adjacent blocks, the resulting fracture will be rather small, but significant.  
         [0049]     Examples of wall structures that may be constructed with the blocks disclosed are depicted in  FIGS. 17 and 18 .  FIG. 17  is a wall W in which the blocks are vertically aligned. As shown, the first four courses are composed of blocks disclosed herein. The top course comprises capstones and does not form part of the invention. Although the blocks are depicted as having roughened front surfaces or facings, it will be appreciated that other textures for the front surface are possible.  FIG. 18  shows a side elevational representation in which various embodiments of the blocks described above may be used to form a retaining wall having an upward receding slope or batter.  
         [0050]     The present invention having thus been described, other modifications, alterations or substitutions may present themselves to those skilled in the art, all of which are within the spirit and scope of the present invention. It is therefore intended that the present invention be limited in scope only by the claims attached below: