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BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to structural building blocks, and to modular systems for constructing composite structures, such as walls and edging which are usable in landscaping. More particularly, the invention relates to an improved structural building block, and to composite structures constructed therewith. 
   2. Background Art 
   Several types of modular landscaping systems are known and in common use today for constructing retaining walls, edging and other landscaping structures. Common landscaping systems include wood timbers and concrete-like blocks. 
   Examples of some of the known landscaping timbers, structural building blocks, and related devices include U.S. design Pat. No. D371,446 to VanDeusen, U.S. design Pat. No. D386,652 to Rimback et al., U.S. design Pat. No. D438,992 to Chrisco et al., U.S. design Pat. No. D448,859 to Doman, U.S. Pat. No. 5,168,678 to Scott, Jr. et al., and U.S. Pat. No. 6,062,772 to Perkins. 
   Although the known landscaping timbers and structural building blocks are usable for their intended purposes, a need still exists in the art for an improved structural building block and modular system, which is usable to build landscaping retaining walls. In particular, there is a need for an improved structural building block which is combinable in a staggered configuration, to build an internally reinforced wall. 
   SUMMARY OF TIE INVENTION 
   The present invention provides a structural building block, which is usable to build a retaining wall, or to make edging for a landscaped outdoor area. A block according to the invention may be interconnectably combined with a plurality of similar blocks, and with fasteners, to build a wall structure. A building block according to a specific embodiment of the invention is constructed and arranged so that any one of a variety of different wall configurations may be made, according to the needs of a particular user. Blocks according to a particular embodiment of the invention may be combined in a staggered configuration, to build a relatively strong, internally reinforced wall. The blocks according to the invention may also be used to form edging at the perimeter of a landscaped outdoor area. 
   A building block according to a first embodiment of the invention includes a block body having front and rear faces, top and bottom surfaces, and first and second ends. The first end of the block has a plurality of spaced-apart fingers extending longitudinally outwardly thereon, substantially parallel to a longitudinal axis of the block. The second end of the block also has a plurality of spaced-apart fingers thereon. The fingers on the second end of the block are oriented and spaced to be alignable with empty spaces between other fingers on the first end of a second, substantially similar block, allowing adjacent similar blocks to nestingly interengage. 
   The fingers have side surfaces which are coextensive with, and substantially flush with the front and rear faces of the block. The tip ends of the fingers are radiused, so that the outside corner edges thereof are rounded off. 
   The uppermost finger on the first end has an upper surface which is substantially flush with the block top surface. Optionally, the upper surface of the uppermost finger may have a recess formed therein to accept a fastener head, allowing the fastener head to be situated at or below the level of the finger&#39;s upper surface. 
   As noted, the second end of the block also includes a plurality of spaced-apart fingers extending longitudinally outwardly thereon. The fingers of the second end are placed on the block body so as to line up vertically with spaces between the fingers of the first end. 
   The lowermost finger on the second end has a lower surface coextensive with, and substantially flush with the block bottom surface. Optionally, the lower surface of the lowermost finger may also have a recess formed therein to accept a fastener head. 
   The fingers of the respective first and second ends have through holes formed therethrough, with the through holes of each end coaxially aligned with one another. Each of the through holes has an axis which is substantially perpendicular to a longitudinal axis of the block. 
   It is an object of the present invention to provide a building block, and a modular system incorporating such building block, which can be used to construct a landscaping wall. 
   It is a further object to provide a building block and modular system which provides the ability to construct curved walls. 
   For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a top plan view of a first structural block in accordance with a first embodiment of the invention; 
       FIG. 1B  is a side plan view of the block of  FIG. 1 ; 
       FIG. 2  is an exploded perspective view of two adjacent blocks and a connector according to the first embodiment; 
       FIG. 3  is a perspective view of a first wall section built using a plurality of blocks according to the first embodiment hereof; 
       FIG. 4  is an expanded view of the wall section of  FIG. 3 , showing how the blocks can be used to form a curved wall; 
       FIG. 5A  is a perspective view of a supplemental block which can be used in conjunction with the block of  FIGS. 1A-1B  as part of a system; 
       FIG. 5B  is a top plan view of the block of  FIG. 5A ; 
       FIG. 5C  is a front plan view of the block of  FIGS. 5A-5B ; 
       FIG. 6  is a perspective view of a second wall section built using a plurality of blocks according to a second embodiment hereof, using the base blocks of  FIGS. 1-2  in combination with a plurality of the supplemental blocks of  FIG. 5 ; 
       FIG. 7  is an expanded view of the wall section of  FIG. 6 , showing how the blocks can be used to form a curved wall; 
       FIG. 8  is a perspective view of a finishing block which is usable with a system according to the present invention; 
       FIG. 9  is a perspective view of a series of interconnected blocks including the finishing block of  FIG. 8 ; 
       FIG. 10  is an exploded perspective view of a connecting block insert and a hollow landscape timber according to a third embodiment of the invention; and 
       FIG. 11  is a top plan view of the insert and landscaping timber of FIG.  10 . 
   

   DETAILED DESCRIPTION 
   First Embodiment 
   Referring to  FIG. 1 , there is shown a structural base block  10  according to a first embodiment of the invention. The block  10  includes a substantially rectangular central block body  11  having a front face  12 , a back face  14 , a top surface  16 , a bottom surface  18 , a first end  20 , and a second end  32  opposite the first end. It will be understood that the block  10  may be made in any practical and appropriate length, such as, e.g., two feet, four feet, six feet, or other desired length. 
   The block  10  may be formed of wood, plastic, cement, or other known material. Where wood is used, treated wood, which is resistant to decay is preferred. Where plastic is used, the blocks may be hollow. 
   Throughout the present specification, relative positional terms like ‘upper’, ‘lower’, ‘top’, ‘bottom’, ‘horizontal’, ‘vertical’, and the like are used to refer to the orientation of the block  10  as shown in the drawings, particularly FIG.  1 B. These terms are used in an illustrative sense to describe the depicted embodiments, and are not meant to limit the scope or application of the invention. It will be understood that the depicted block  10  may be placed at an orientation different from that shown in the drawings, such as inverted 180 degrees or oriented transversely to the orientation shown, and in such a case, the above-identified relative positional terms will no longer be accurate. 
   In the base block  10  of  FIG. 1 , the first end  20  includes first and second fingers  24 ,  26  integrally formed with, and extending outwardly from the central block body  11 . The first or uppermost finger  24  includes an upper surface  25 , which is coextensive with, and flush with the top surface  16  of the block. The second finger  26  is located directly below the first finger  24  and is spaced away therefrom, thereby forming a gap  28  between the first and second fingers. The second finger  26  is substantially the same size as the first finger  24 . Optionally, the height of each of the fingers  24 ,  26  may be approximately one fourth of the height of the block body  11 , as shown in the drawing. A second gap  30  is provided directly below the lower second finger  26 . The height of each of the gaps  28 ,  30  is just slightly larger than the height of one of the fingers  24  or  26 . 
   As seen in the top view of  FIG. 1A , the outer corners, at the tip ends of each of the first and second fingers  24 ,  26  are chamfered, or rounded off at the edges thereof. This may also be described as radiused, because the straight-line horizontal distance (radius) from the vertical center line of the hollow bore  42  in the fingers to any point on the outer surface of the finger tip should be approximately a constant value. 
   The second end  32  of the block  10  is substantially identical to the first end  20 , if the block of  FIG. 1B  was rotated 180 degrees clockwise around the center point thereof. The second end  32  includes third and fourth fingers  34 ,  36 , which are the same size as the first and second fingers  24 ,  26 . The third, or lowermost finger  34  includes a lower surface  35  which is coextensive with, and flush with the block bottom surface  18 . The fourth finger  36  is located directly above the third finger  34  and spaced upwardly away therefrom, thereby forming a gap  38  between the third finger  34  and the fourth finger  36 . Another gap  40  is located directly above the fourth finger  36 . These gaps  38 ,  40  are slightly larger than the vertical height of one of the fingers. 
   The tip portions of the fingers  34 ,  36  are radiused, as previously discussed, and also have coaxially located through-holes  42  formed therein. 
   It will be seen from  FIG. 1B  that the gap  28 , between the first and second fingers  24 ,  26 , is vertically aligned with the fourth finger  36  on the opposite side of the block  10 , and the gap  30 , below the second finger  26 , is vertically aligned with the third finger  34 . The respective fingers and gaps are dimensioned to allow the second end of a first block  10   a  ( FIG. 2 ) to nestingly interengage with the first end of a second, identical block  10   b , with the top and bottom surfaces of the respective blocks being substantially aligned. 
   Optionally, the lower surface  35  of the third finger  34  may have recesses  44  formed therein (FIG.  1 B), to accept the head of a fastener  70 , thereby making the fastener flush with the respective top or bottom surface of the block. In this way, blocks having fasteners installed therein may be vertically stacked on top of one another, if desired, without the fasteners creating unwanted space therebetween. Formation of a recess in the third finger  34  makes the first and second ends  20 ,  32 , identical and interchangeable, so that the block is never upside down. 
     FIG. 2  shows an exploded perspective view of two blocks  10   a ,  10   b  and a fastener  70  for interconnecting the blocks. 
   The first block  10   a  and second, substantially identical block  10   b  are joined together when the third and fourth fingers  34  and  36  of the first block nestingly engage into the gaps  28 ,  30  next to the fingers  24  and  26  of the second block. With the fingers nested together and the holes  42  aligned with one another, a fastener  70  is then pushed through the holes, thereby pivotally joining the blocks together. 
   The fastener  70  includes a substantially straight and cylindrical shaft  72 , and an enlarged head  74  attached to an end of the shaft. The exact shape of the fastener head  74  is not critical. Where a recess  44  is used to receive the fastener head  74 , the recess should be formed in a shape corresponding to the shape of the fastener head. 
   Since the ends of the fingers are radiused, as discussed above, the blocks  10   a ,  10   b  can be pivotally moved relative to one another around the fastener  70 , to any desired angular relation up to 90 degrees, until the blocks contact and interfere with one another. In the larger view, this permits the formation of curved walls such as that shown in FIG.  4 . 
   Optionally, the blocks  10  according to the invention may be formed from a single beam of wood or other starting material, and may be cut out using a laser beam, in an inert gas atmosphere. Nitrogen gas may be used. A five kilowatt laser may be required for this process. Such a method of making the blocks makes a very efficient use of the material, and produces blocks having darkened, carburized surfaces where the cuts have been made. 
   Wall Construction 
   Aligning a multiplicity of blocks  10  in a manner as described, and connecting the blocks with fasteners  10 , a user can build a landscaping retaining wall in any desired shape that the pivotally movable blocks  10  can be placed into. 
   A first example of a wall  100  built with a multiplicity of blocks  10 , according to the first embodiment of the invention, is shown in FIG.  3 . In the wall of  FIG. 3 , all of the blocks  10  in a given row are lined up end-to-end with coplanar top surfaces and coplanar bottom surfaces. 
   A plurality of structural blocks  10   a - 10   f  can be joined together to form a wall  100  as illustrated in FIG.  3 . Each row of blocks is assembled in a manner such that the fingers of each block nest with the corresponding fingers of an adjacent block, with the upper surfaces  16  of the adjacent blocks in horizontal alignment with one another, thereby creating distinct, vertically stacked rows of blocks. 
   While two rows of blocks are shown in  FIG. 3 , it will be understood that three, four or more rows may be used, as appropriate for a particular installation. 
   The blocks  10  are fastened together and to the substrate  120  with fasteners  70 , such that the fasteners pass through the through holes  42  and into the substrate, thereby joining the blocks together and securing the wall structure to the substrate, which may be ground. The head  74  of each fastener  70  fits into the recess  44  at the top of the finger through-holes  42 , thereby making the fastener head flush with the surface of the respective block. 
   If desired, some of the fasteners can be made extra long, or else can be installed so that they extend down into the cement or other substrate that the wall  100  is being built on. 
   Alternatively, in the wall design of  FIG. 3 , where appropriate, a single, long fastener  70  may be used, for each connection point between adjacent blocks, to extend downwardly through all of the rows of blocks. The use of a single, long fastener  70  at each connection point also serves to join the vertical rows together. This long fastener may further extend through the blocks and into the substrate  120  to anchor the wall in place. 
   A larger three-dimensional view of the wall  100 , showing curvature on part of the wall caused by pivotally moving selected blocks relative to one another, is shown in FIG.  4 . Once such a wall is built, and placed into the preferred orientation thereof, dirt may be filled in behind the wall to provide a terraced effect. 
   As previously noted, blocks  10  of different lengths can be made, and optionally, in the practice of the present invention, different length blocks could be combined with one another. This allows for an overall shape of a landscaped area that is flat, rounded or and/or curved in different sections thereof, according to the requirements of a particular user. The shape of the landscaped area can be customized to fit the available space for a particular application. 
   Supplemental Short Block 
     FIG. 5  illustrates a supplemental short block  210  according to a second embodiment of the invention. The short block  210  is provided for use in combination with the base block  10 , to build a reinforced wall  200  (FIG.  6 ), in which the base blocks  10  are arranged in a vertically staggered configuration. 
   The short block  210  resembles one of the base blocks  10  which has been cut in half along a horizontal center plane thereof and had one of the resulting pieces removed. 
   The short block  210  includes a rectangular block body  211  having front and back faces  212 ,  214 , top and bottom surfaces  216 ,  218  and first and second ends  220 ,  222 . The first end  220  of the block  210  has a single, upper finger  224  extending outwardly thereon above a gap  230 . The second end  222  of the block  210  has a single, lower finger  226  extending outwardly thereon below a gap  232 . Each finger has a through-hole  238  formed therein and an enlarged recess  240  for accepting a fastener head. 
   Alternate Wall Construction 
     FIGS. 6-7  illustrate a wall which can be constructed using both the base blocks  10  and the short blocks  210 . If the base blocks  10  are alternated with the short blocks  210  in a first row of a wall, a base row having a staggered upper profile is achieved. Wherever short blocks  210  (such as that shown at  200   a ) are found in the lower row, a base block  10  is set on top of each short block  210 , with yet another short block  210  (such as that shown at  200   b ) stacked thereon, as shown (for a wall of the height illustrated). 
   In this way, a reinforced wall construction  200  is realized in which the base blocks  10  are vertically staggered relative to one another. Fasteners  70  are used in a manner similar to that used in constructing the wall  100  of FIG.  3 . 
   This creates an internally reinforced wall having greater strength and structural integrity than the wall  100  of  FIGS. 3-4 . In the wall  200  according to the second embodiment, the subsequent rows are interdependent and interconnected to one another. 
   It will be understood that this pattern may be modified to make a wall of any desired height, and that for a different wall height, more of the base blocks  10  could be used between the top and bottom rows. For a higher wall, the second row would all be base blocks  10 , which could be repeated for additional rows as desired. 
     FIG. 7  illustrates that the wall  200  may also be made with some curvature therein, as desired, and may be used as a retaining wall for landscaping purposes. 
   Optional Finishing Block 
   Referring now to  FIGS. 8-9 , an optional finishing block in accordance with the invention is shown generally at  50 . The finishing block  50  is provided for optional use in making an end wall face with a substantially smooth side edge. The block  50  has a first end  52 , which is substantially similar to the first end  20  of the base block  10 , as previously described. The first end  52  of the finishing block  50  has two spaced-apart fingers  54 ,  56  extending outwardly thereon, which are the same size, shape and orientation as the first and second fingers  24 ,  26  on the base block  10 . 
   The finishing block  50  also has a second end  60  with an outer edge  62  having a substantially smooth and unbroken surface. The outer edge  62  of the finishing block  50  can be oriented substantially vertically, or may alternatively be disposed at an angle with respect to the vertical, as shown. 
     FIG. 9  illustrates how the finishing block  50  may be combined with two of the base blocks  10   a ,  10   b  to form a series having a substantially smooth and unbroken outer edge. 
   Insert Member—Third Embodiment 
   An optional insert member  310  is shown in  FIGS. 10-11 , according to a third embodiment of the invention. The insert member  310  is intended for use in conjunction with a hollow, plastic landscaping timber  390 . 
   The insert member  310  includes a reduced diameter section  384  for slidable placement inside of the open end  394  of the landscaping timber  390 , and a larger working section  386  having a plurality of fingers  324  and  326  thereon, which will nestingly interconnect with corresponding fingers on similar end block insert members. The landscaping timber has a plurality of holes  391 ,  392  formed therein, and the reduced diameter section  384  of the insert member has corresponding three-dimensional extensions  387 ,  388  protruding outwardly thereon for locking engagement in the holes  391 ,  392 . 
   The structure of the working section  386  is similar to the corresponding portion of the base block  10 , as previously described. It will be understood that an insert in the orientation shown in  FIG. 8  may be nestingly interengaged with a similar insert which has been inverted top-to-bottom and rotated 180 degrees from the orientation of the insert in the drawing. 
   Although the present invention has been described herein with respect to a limited number of presently preferred embodiments, the foregoing description is intended to be illustrative, and not restrictive. Those skilled in the art will realize that many modifications of the preferred embodiment could be made which would be operable. All such modifications, which are within the scope of the claims, are intended to be within the scope and spirit of the present invention.

Summary:
A building block includes a substantially rectangular block body, and may be used to make walls or edging for a landscaped area A first end of the block has spaced-apart fingers extending outwardly thereon. The outside corners of the finger tips are rounded off. The uppermost finger on the first end has an upper surface flush with the block top surface. Holes are formed coaxially through the fingers of the first end, with an axis substantially perpendicular to the block&#39;s longitudinal axis. Pins may be placed in the through holes to interconnect nested blocks. The second end is identical to the first end, rotated clockwise 180 degrees. Accordingly, the lowermost finger of the second end has a lower surface flush with the bottom surface of the block body. Multiple blocks may be combined with supplemental, reduced height blocks, and assembled in a staggered configuration to build a reinforced wall.