Abstract:
A block for use in constructing a retaining wall having a bottom with a non-planar portion which creates a gap between the bottom surface and the top surface of a lower course of similar blocks when the block is placed thereon. This gap assists the block in resting on the lower course of blocks in a stable, level manner by providing a space where small amounts of rubble and dirt may exist without interfering with the stacking of the blocks. The non-planar, preferably concave, portion is also advantageous in that it reduces the unit weight of the block without significantly affecting the structural integrity of the block. Preferably, the block&#39;s bottom surface further comprises a plurality of grooves which further reduce the weight of the block and provide additional clearance in the gap for larger stones. It is envisioned that these grooves be “V” shaped, thereby having angled walls which act to funnel the larger stones into an area of adequate clearance when the block is being placed on a lower course of similar blocks.

Description:
CROSS REFERENCES  
       [0001]    This application is a continuation in part of U.S. patent application Ser. No. 09/377,094 filed on Aug. 19, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates generally to the construction of retaining walls used in landscaping applications. Such walls are used to provide lateral support between differing ground levels where the change in one elevation to the other occurs over a relatively short distance, thereby reducing the possibility of erosion and landslides. Retaining walls can be both functional and decorative and range from small gardening applications to large-scale construction. They are constructed of a variety of materials and shapes. Some have been constructed of wood timbers, others of rock in a natural form (such as limestone). Still others have been constructed of manufactured aggregate or concrete blocks. The present invention relates to a manufactured block.  
           [0003]    Constructing a fit and true retaining wall can be an arduous endeavor. In addition to laying a level first course on ground which is usually located at the foot or in the side of a steep embankment, the builder must ensure that each subsequent course is level. An error made in a lower course usually gets exaggerated as higher courses are stacked above it. As a wall made of blocks necessarily develops somewhat of a grid-like appearance, interruptions or undulations in the lines of the wall become readily apparent to the human eye.  
           [0004]    One particular problem the prior art has failed to overcome is developing a retaining wall block shaped to avoid these undulations and interruptions which are caused by blocks being stacked on dirt or debris found on the upper surface of the lower course of blocks. Dirt presents itself as a result of the fill material used to fill the gap between the rear of the wall and the earth it is being built to retain. This fill material usually consists of small, coarse rocks. They serve as a barrier between the earth and the wall and prevent wet earth from seeping through the bricks of the wall during inclement weather. Present wall building methods include laying a course of blocks, filling the space behind the course with fill material, packing the fill material, and carefully sweeping the dirt off of each completed course prior to the addition of the next course. This final, sweeping step is time consuming but necessary to ensure the next course of blocks lies flat on the lower course.  
           [0005]    Some larger blocks incorporate continuous cavities that extend from their bottom surface to their top surfaces. These cavities are intended to reduce the amount of material required to form the block, thereby reducing its cost and weight, and also allow an area to be filled with fill material once a course is finished. At first blush it would appear that, because the presence of cavities reduces the surface area of the top and bottom of the block, they would also serve to decrease the area for interference by small stones and debris between courses. However, because the cavities are filled with fill material, the fill material spills over the upper surfaces and exacerbates, rather than alleviates, the problem. Furthermore, smaller blocks cannot incorporate cavity portions without jeopardizing their structural integrity.  
           [0006]    The inability of smaller blocks to accommodate cavity portions creates further problems. Making a solid block out of concrete results in a dense rock which is heavy for its relatively small size. Working with these rocks can become cumbersome. The absence of cavities or interruption in the side walls makes these blocks difficult to lift. They have few areas which lend themselves to easy gripping and lifting. This becomes an important consideration in light of the number of blocks that must be lifted and set in place during the construction of even a relatively small retaining wall.  
           [0007]    It would be desirable to develop a retaining wall block shaped to accept a certain amount of dirt and debris from course to course without adversely affecting the overall structure and aesthetics of the resulting wall. It would also be desirable to devise a small retaining wall block which has a reduced unit weight due to the absence of block material in an area that will not adversely affect the strength of the block or its appearance. Finally, it would be desirable to provide a small retaining wall block which is relatively easy to grasp and pick up off of a stack of similar blocks.  
           [0008]    These and other objectives and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention advantageously provides a block for use in building a retaining wall that produces a level course of blocks, despite the presence of a small amount of debris on the lower course of blocks.  
           [0010]    The present invention is also advantageous in that it provides a relatively small block with material removed from strategic locations to provide a block which is lighter than it would have been had it been solid, yet the removal of material has not adversely affected the strength of the block, nor the appearance of the resulting wall.  
           [0011]    The present invention advantageously provides a block which has areas for a person building a retaining wall to grasp the block when lifting the block off of a stack of such blocks and placing the block on a lower course of blocks in the wall being constructed.  
           [0012]    The instant invention relates to a retaining wall block so shaped that when placed on top of a lower course of similar blocks, it lies flat despite the inevitable presence of dirt, small stones, and other debris. This feature alleviates the time-consuming step of meticulously cleaning the top of each course of blocks before the next course may be laid on top of it.  
           [0013]    The block generally comprises a continuous top surface, front and back surfaces extending from the top surface, multi-faceted side surfaces extending from the top surface and spanning from the front surface to perpendicularly intersect the back surface, and a bottom surface having a predetermined surface area that is integral with the front and side surfaces. A gutter is formed into the bottom surface of the block and is spaced away from the rear surface of the block. The gutter formed into the bottom surface of the block preferably has a forward edge that has a minimal surface area that acts to support a rear portion of the block upon a lower course of blocks.  
           [0014]    In order to further lighten a block constructed according the present invention, the multifaceted side surfaces of the blocks include an inwardly inset sidewall portion that perpendicularly intersects the rear surface of the block. The multifaceted side surfaces of the block may further comprise a shoulder formed between the aforementioned sidewalls and a forward portion of the multifaceted side surfaces wherein the shoulder and the forward portion of the multifaceted side wall intersect at an obtuse angle.  
           [0015]    In order to achieve the tolerance of small stones and debris between courses, a portion of the bottom face of the block of the present invention is non-planar, and more preferably, concave. This concave surface significantly reduces the area for block to block contact between successive courses. Preferably, this non-planar portion covers more than one half of the area of the bottom surface of the block. It also functions to provide an area of clearance or a gap between the stones where debris can migrate without causing interference or instability between courses. The concave portion is preferably shaped to form a portion of a cylinder and extends from one side surface to the other. Alternatively, the concave portion could be shaped to form a portion of a sphere or any other shape.  
           [0016]    In addition to the concave portion of the bottom surface, the present invention further comprises a plurality of grooves formed in the bottom surface and preferably extending transversely of the bottom surface between the front and back surfaces. The grooves preferably are angled inwardly to form an inverted “V” shape when the block is given its intended orientation. The grooves allow spaces of increased clearance for larger stones. The grooves preferably comprise two opposed surfaces of a predetermined width extending the length of the groove. The two surfaces are angled to form a “V” shape and meet to form an angle α. The angled walls of the grooves not only reduce the weight of the block and act as a splitting aid, but also act to funnel larger stones into the grooves, thereby positioning them into an area of maximum clearance.  
           [0017]    Alternatively, the first and second surfaces may be joined by a third, curved or flat, surface juxtaposed between the first and second surfaces. Such a third surface would give the groove an inverted “U” shape. The grooves are cut into the block and have a set depth which follows the irregular contour of the non-planar bottom surface.  
           [0018]    Preferably, the bottom surface further comprises one or more downward projections proximate the rear surface and having an abutting surface which contacts the rear surface of a lower course of blocks when the block is stacked thereon. It is envisioned that the abutting surface is either parallel to the rear surface of the block, or forms an angle β, with the rear surface. These projections create an automatic and uniform setback among successive courses of blocks so that the resulting retaining wall is angled rearwardly. This also adds resistive strength to the wall against the natural forces exerted on the wall by the earth the wall is retaining by tying successive courses of blocks into those course below them. Preferably, the downward projection has a generally trapezoidal cross-sectional shape and is spaced away from the rear surface of the block. In addition, the abutting surface of the downward projection is preferably integral with a rear face of the gutter. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of a block of the present invention, looking up at the bottom to reveal the details of the bottom surface;  
         [0020]    [0020]FIG. 2 is a cross sectional view of the block of the present invention taken along lines  2 - 2  of FIG. 1;  
         [0021]    [0021]FIG. 3 is a cross sectional view of the block of the present invention taken along lines  3 - 3  of FIG. 1 and shown with other blocks in phantom, stacked, as in a retaining wall;  
         [0022]    [0022]FIG. 4 is a bottom plan view of the block of FIG. 1;  
         [0023]    [0023]FIG. 5 is a perspective view of the block shown in FIG. 1 in a stacked relationship with other blocks, as in a wall, and showing debris resting on a lower course of blocks and accommodated for by the concave area of the bottom surface of the block of the present invention;  
         [0024]    [0024]FIG. 6 is a perspective view of an alternative embodiment of the present invention, looking up at the bottom to show the detail of the bottom surface;  
         [0025]    [0025]FIG. 7 is a sectional elevational view taken along lines  7 - 7  of FIG. 6;  
         [0026]    [0026]FIG. 8 is an end elevational view of a block of the embodiment shown in FIG. 6, in stacked relation, as in a wall, with other blocks shown in phantom;  
         [0027]    [0027]FIG. 9 is a bottom plan view of a block of the embodiment shown in FIG. 6;  
         [0028]    [0028]FIG. 10 is a bottom plan view of a block of the present invention;  
         [0029]    [0029]FIG. 11 is a cross-sectional view of the block of FIG. 10 taken along cutting lines  11 - 11  in FIG. 10;  
         [0030]    [0030]FIG. 12 is a cross-sectional view of the block of FIG. 10 taken along cutting lines  12 - 12  in FIG. 10;  
         [0031]    [0031]FIG. 13 is a top plan view of the block of FIG. 10;  
         [0032]    [0032]FIG. 14 is a front elevational view of the block of FIG. 10;  
         [0033]    [0033]FIG. 15 is a side elevational view of a first side of the block of FIG. 10; and,  
         [0034]    [0034]FIG. 16 is a side elevation view of a second side of the block of FIG. 10. 
     
    
     DETAILED DESCRIPTION  
       [0035]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined only by the claims.  
         [0036]    Referring now to FIG. 1, there is shown a retaining wall block  10  having a front surface  12 , side surfaces  14   a  and  14   b  extending rearwardly from front surface  12  and integral with rear surface  16 . Top surface  18  is generally planar and continuous across its extents. Top surface  18  extends from side surface  14   a  to side surface  14   b,  and from front surface  12  to rear surface  16 . Preferably, top surface  18  is generally perpendicular to side surfaces  14   a  and  14   b,  and also to front surface  12  and rear surface  16 .  
         [0037]    In the embodiment shown in FIGS.  1 - 9 , front surface  12  comprises three parts,  12   a,    12   b,  and  12   c.  Part  12   c  is generally parallel to rear surface  16  and lies between parts  12   a  and  12   b . Parts  12   a  and  12   b  are angled such that the extend from part  12   c  and diverge rearwardly to meet side surfaces  14   a  and  14   b , respectively. Parts  12   a ,  12   b , and  12   c  are shown as split faces as opposed to formed faces. Creating a face with a rock splitter results in an irregular, more natural appearing surface. Also shown in the Figures is a rear surface  16  which has a smaller width than front surface  12  such that side surface  14   a  and  14   b  must converge rearwardly in order to be integral with rear surface  16 . This shape allows the construction of straight, concave, convex, or serpentine walls without interrupting the relatively uniform appearance created by the front surfaces  12  of a plurality of blocks  10  forming a wall.  
         [0038]    Bottom surface  20  extends from front surface  12  to rear surface  16  and from side surface  14   a  to side surface  14   b . Bottom surface  20  includes concave, or non-planar portion  22 . Concave portion  22  is depicted in FIGS. 1, 3 and  4  as a relatively cylindrical indentation in bottom surface  20 , extending from side surface  14   a  to side surface  14   b . Preferably, portion  22  does not extend forward of where side surfaces  14   a  and  14   b  meet parts  12   a  and  12   b  of front surface  12 . This way concave portion  22  is not visible in a completed wall, regardless of whether the wall is straight, concave, convex, or serpentine.  
         [0039]    Allowing concave portion  22  to extend from side surface  14   a  to side surface  14   b  creates a gap  24  between the bottom surface  20  and the upper surface of a lower course of blocks when block  10  is placed thereon. This gap  24  may be used for ease in picking the block up and setting the block down. Also, as shown in FIGS. 1, 3 and  4 , concave portion  22  extends rearwardly but ends forward of downward projection  34 , which is described in more detail below. Ending the concave or, non-planar portion  22  forward of downward projection  34  provides another flat surface for block to block contact to assist in the leveling and stabilization of block  10  on a lower course of blocks.  
         [0040]    Alternatively, it is envisioned that concave portion  22  be an indentation of any shape, such as the generally spherical shape of the embodiment shown in FIGS.  6 - 9 . Preferably, portion  22  is large enough to occupy at least 30 percent, more preferably on the order of 50 to 75 percent, of the surface area of bottom surface  20 .  
         [0041]    In one embodiment, bottom surface  20  also includes at least one, preferably a plurality of, grooves  28 . As shown in FIG. 2, grooves  28  are preferably “V”-shaped and extend from the bottom surface into the block toward top surface  18 . In the embodiment depicted in FIGS. 1 and 2, grooves  28  are spaced generally equidistant from each other and oriented such that they extend from front to back generally across the non-planar portion  22 . It is envisioned that grooves  28  could be located generally anywhere across bottom surface  20 . It is preferred, however, that grooves  28  do not intersect front surface  12  so that grooves  28  remain hidden from view when block  10  is part of a completed wall.  
         [0042]    Grooves  28  having the preferred “V” shape generally comprise at least a first surface  30  and a second surface  32 . First surface  30  extends from bottom surface  20  and is integral with second surface  32 . Second surface  32  extends from first surface  30  to bottom surface  20  thereby forming an angle a between first surface  30  and second surface  32  as seen in FIGS. 2 and 7. Angle α is preferably less than 180 degrees. Alternatively, first surface  30  and second surface  32  could be joined by a third surface (not shown in the Figures) which extends along the length of the groove and is juxtapose between the first and second surfaces. This third surface could be curved, thereby forming a “U” shaped groove, or the third surface could be flat, thereby forming a rectangular groove. However, a “V” shaped groove generally eases manufacturing.  
         [0043]    As shown in all Figures, bottom surface  20  also includes at least one downward projection  34 . Downward projection  34  may extend across bottom surface  20 , adjacent rear surface  16  as shown in FIGS. 1, 2, and  4 . Alternatively, projection  34  may be broken into more than one projection  34  as shown in FIGS. 6, 7 and  9 . Projection  34  has an abutting surface  36  which is used to abut against the rear surface  16  of a lower course of blocks, thereby forming a setback between successive courses of blocks. This setback add strength and stability to the resulting wall.  
         [0044]    Abutting surface  36  may be substantially parallel to rear surface  16 . Alternatively, for ease of manufacture, abutting surface  36  may angle rearwardly forming a relatively small angle β with rear surface  16  as shown in FIG. 3. Angle β is preferably less than 45 degrees, more preferably less than 30 degrees. A smaller angle β provides more resistance to horizontal block slippage due to external forces against the back of the resulting wall.  
         [0045]    Referring now to FIGS.  10 - 16 , there is shown a preferred embodiment of a retaining wall block  50  having a front surface  52 , side surfaces  54   a  and  54   b  extending rearwardly from front surface  52  toward rear surface  56 . Top surface  58  is generally planar and continuous across its extents. Top surface  58  extends from side surface  54   a  to side surface  54   b , and from front surface  52  to rear surface  56 . Preferably, top surface  58  is generally perpendicular to side surfaces  54   a  and  54   b , and also to front surface  52  and rear surface  56 .  
         [0046]    In the embodiment shown in FIGS.  10 - 16 , front surface  52  comprises three parts,  52   a ,  52   b , and  52   c.  In general, these parts will referred to as the front surface parts or as the face of the block  50 . Part  52   c  is generally parallel to rear surface  56  and lies between parts  52   a  and  52   b.  Parts  52   a  and  52   b  are angled such that they extend from part  52   c  and diverge rearwardly to meet side surfaces  54   a  and  54   b , respectively.  
         [0047]    Parts  52   a ,  52   b , and  52   c  are in FIGS.  10 - 16  shown as formed or smooth faces as opposed to split faces. Block  50  may preferably be formed by splitting as described above in conjunction with FIGS.  1 - 9 . Creating a face with a rock splitter results in an irregular, more natural appearing surface. As can be seen in the Figures, rear surface  56  has a smaller width than front surface  52 . Side surfaces  54   a  and  54   b  converge rearwardly toward the rear surface  56  at obtuse angle to the rear surface  56 . This shape allows the construction of straight, concave, convex, or serpentine walls without interrupting the relatively uniform appearance created by the front surfaces  52  of a plurality of blocks  10  forming a wall.  
         [0048]    Block  50  has a heel portion  70  that comprises the rear surface  56 , a projection  72  and a gutter  74 . As can be seen most clearly in FIGS. 10 and 13, sides  54   a  and  54   b  incorporate shoulders  76   a  and  76   b , respectively. Shoulders  76  may also be seen as a forward boundary of the heel portion  70  of the block  50 . Note that shoulders  76  form an obtuse angle with respect to sides  54 . Heel portion side walls  78   a  and  78   b  extend rearwardly from respective shoulders  76   a  and  76   b  and intersect with rear surface  56  of block  50 . Heel portion side walls  78   a  and  78   b  are preferably formed perpendicular to shoulders  76   a  and  76   b  and to rear surface  56  of block  50 . The resulting sides  54  comprise multiple facets and provide a number of benefits. Formation of side walls  78   a  and  78   b  as illustrated in the Figures results in a lighter block  50  as the block  50  will have a smaller volume. As a corollary benefit, less concrete material is used in the formation of block  50  where side walls  78   a  and  78   b  are formed as indicated.  
         [0049]    Bottom surface  60  extends from front surface  52  to gutter  74  and from side surface  54   a  to side surface  54   b . Bottom surface  60  includes concave, or non-planar portion  62 . Concave portion  62  is depicted in FIGS. 11, 12,  15 , and  16  as a relatively cylindrical indentation in bottom surface  60 , extending from side surface  54   a  to side surface  54   b . Preferably, portion  62  does not extend forward of where side surfaces  54   a  and  54   b  meet parts  52   a  and  52   b  of front surface  52 . In this way concave portion  62  will not be visible in a completed wall, regardless of whether the wall is straight, concave, convex, or serpentine.  
         [0050]    Allowing concave portion  62  to extend from side surface  54   a  to side surface  54   b  creates a gap  64  between the bottom surface  60  and the upper surface of a lower course of blocks when block  50  is placed thereon. This gap  64  may be used for ease in picking the block  50  up and setting the block down. As can be seen in FIGS. 11, 12,  15 , and  16 , gap  64  extends all the way to the edge  75  of gutter  74 . Because gap  64  extends all the way to edge  75  of gutter  74 , a block  50  in an upper course of blocks will rest upon a block  50  in a lower course of blocks upon that portion of bottom surface  60  that extends between the front face parts  52   a ,  52   b , and  52   c  and the forward edge  63  of the concave portion  62  and the edge  75  of gutter  74 . As can be appreciated, the rear of the block  50  is supported only on edge  75  and not on a planar surface, i.e. edge  75 , while having any number of curvilinear and/or rectilinear shapes, has a small surface area with respect to the remainder of bottom surface  60 . This affords the benefits of increased friction between two courses of blocks  50  and prevents the entrapment of sand, gravel, or bits of concrete between the upper surface  58  of a lower course of blocks and the bottom surface  60  of an upper course of blocks.  
         [0051]    Gutter  74  extends upwardly from edge  75  into the body of block  50  toward the top surface  58 . Gutter  76  extends laterally between heel portion side walls  78   a  and  78   b  and has a generally “U” shaped cross-sectional area. Note that the exact cross-sectional shape of the gutter  76  may vary. However it is important to form the gutter  74  without sharp-edged concave surfaces. Therefore, the cross-sectional shape of the gutter  74  will be gently curved within the constraints of its position and size. Such a shape avoids the formation of unwanted stress concentration points that might facilitate the fracture of the block.  
         [0052]    The rear face of the gutter  74  extends downwardly, away from the top surface of block  50  and beyond edge  75  to form an abutting surface  80  of projection  72 . Projection  72  and its abutting surface  80  function in the same manner as projection  34  and its abutting surface  36 , described above. That is, projection  72  acts to rearwardly offset each course of blocks  50  from the lower course upon which the upper course of blocks  50  rest. Projection  72  is preferably offset forwardly from the rear surface  56 . As can be seen in the Figures, rear face  82  of projection  72  is moved forward of the rear surface  56  of the block  50 . Additionally, it is preferred to cant the rear face  82  of projection  72  forwardly so that the projection has a generally trapezoidal cross-sectional shape with radiused edges. While this trapezoidal shape is not the only shape that may be used, it does afford additional durability to the projection  72  in that the lack of sharp edges prevents chipping and fracture of the projection  72 . The trapezoidal shape of the abutting surface  80  of the projection  72  aids in the rapid construction of walls by preventing the entrapment of sand, gravel, or pieces of concrete between the abutting surface  80  of the projection  72  of a block  50  in an upper course and the rear surface  56  a block  50  in a lower course.  
         [0053]    The formation of a heel structure  70  such as that illustrated in FIGS.  10 - 16  has the additional benefit of strengthening the projection  72  by forcing more of the concrete from which the blocks  50  are formed into the area of the mold that forms the projection  72 . Projection  72  of block  50  therefore has fewer voids, is more dense and is consequently stronger.  
         [0054]    In the preferred embodiment, bottom surface  60  also includes at least one, and preferably a plurality of, grooves  86  that are similar in shape and disposition to the grooves  28  described above in conjunction with FIGS. 1 and 2. Grooves  86  preferably have the “V”-shape as described above. While the grooves  86  may be located generally anywhere across the bottom surface  60 , it is preferred to locate the grooves substantially within the curved portion  62  of the bottom surface  60 . As seen in FIG. 10, grooves  68  may extend from front to back from a position on surface  60  somewhat forward of the point where front surfaces  52   a  and  52   b  interest side surfaces  54   a  and  54   b , respectively, to a position just forward of edge  75  of gutter  74 . Care must be taken to space the grooves  86  away from edge  75  sufficiently to avoid weakening edge  75 . Grooves  86  not only result in a lighter block  50 , but also realize a cost savings in the use of less concrete to form the blocks  50 . Additionally, grooves  86  may aid installers in the field by providing a fracture line along with the block  50  may be broken to fill a gap in wall made from blocks  50 .  
         [0055]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.