A method for interlocking precast concrete sections to create a unified whole. The method allows precast pieces to be substituted for in situ castings in certain applications. Each precast concrete piece has an interlocking feature. The interlocking features are pierced by at least one transverse opening. Once the transverse openings are aligned, a user pours a solidifying substance such as wet concrete into the aligned transverse holes. A reinforcing metal bar may also be placed in the holes. Once the concrete hardens, the precast pieces are linked together.

CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    Not Applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       MICROFICHE APPENDIX 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    This invention relates to the field of construction. More specifically, the invention comprises a method for interlocking precast concrete segments to create a larger concrete assembly. 
         [0006]    2. Description of the Related Art 
         [0007]    Many concrete assemblies are presently cast in situ. One good example is a concrete sidewalk. The ground beneath the sidewalk is smoothed and leveled. Forms are then placed to define the sidewalk's lateral edges. Wet concrete is then poured into the forms and allowed to harden. After the concrete is sufficiently cured, the forms are removed. 
         [0008]    A second example is the casting of reinforced concrete floors in commercial buildings. Once a steel substructure is in place, forms are placed around the area to be poured. The concrete is then poured and allowed to cure with the forms in place. 
         [0009]    These known techniques produce a good finished assembly, but they are time and labor intensive. The installation of the forms is a skilled process that simply does not lend itself to automation. The curing of the concrete is also subject to the prevailing environmental conditions. Those skilled in the art will know that the ultimate strength obtained by concrete is largely dependent upon the temperature and humidity present during the cure period. 
         [0010]    On the other hand, precast concrete structures can be manufactured in a factory setting where temperature and humidity can be controlled. The aggregate mix quality may likewise be controlled. The factory setting also allows significant automation. It would therefore be advantageous to provide a construction method allowing precast concrete structures to be used in a setting which has traditionally required casting in situ. The present invention proposes just such a method. 
       BRIEF SUMMARY OF THE PRESENT INVENTION 
       [0011]    The present invention comprises a method for interlocking precast concrete sections to create a unified whole. The method allows precast pieces to be substituted for in situ castings in certain applications. The construction of sidewalks is one suitable application. Rather than forming a casting the sidewalk in place, a group of precast concrete links are used. Each link has interlocking features such as a first tang extending outward from a first end and a second tang extending outward from the opposite end. 
         [0012]    The first and second tangs are pierced by at least one transverse opening. The tangs are configured so that when two links are aligned the tangs will overlap and the transverse openings through the tangs will align. Once the links are properly positioned, a user pours wet concrete into the aligned transverse openings. A reinforcing metal bar may also be placed in the openings. Once the concrete hardens, the tangs are linked together. Using this method, a sidewalk of any desired length may be created. The inventive method may also be applies to linking precast concrete plates or other types of precast concrete pieces. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING VIEW 
         [0013]      FIG. 1  is a perspective view, showing a precast sidewalk link. 
           [0014]      FIG. 2  is a perspective view, showing the opposite side of the sidewalk link of  FIG. 1 . 
           [0015]      FIG. 3  is a section view, showing the tang and the transverse hole through the tang. 
           [0016]      FIG. 4  is a perspective view, showing how two sidewalk links may be assembled. 
           [0017]      FIG. 5  is a perspective view, showing the alignment of two sidewalk links. 
           [0018]      FIG. 6  is a perspective view, showing the addition of concrete to the aligned transverse holes in order to lock two sidewalk links together. 
           [0019]      FIG. 7  is a perspective view, showing the assembly of  FIG. 6  after the sidewalk links are locked together. 
           [0020]      FIG. 8  is a section view, showing how two adjacent sidewalk links are tied together. 
           [0021]      FIG. 9  is a perspective view, showing a series of sidewalk links tied together. 
           [0022]      FIG. 10  is a perspective view, showing an assembly of an alternate form of the sidewalk links. 
           [0023]      FIG. 11  is a perspective view, showing two precast concrete plates configured for use in the present inventive method. 
           [0024]      FIG. 12  is a perspective view, showing the placement of precast concrete plates on a steel truss structure. 
           [0000]    
         
           
                 
               
                 
                 
                 
                 
               
             
                 
                     
                 
                 
                   REFERENCE NUMERALS IN THE DRAWINGS 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                   10 
                   sidewalk link 
                   12 
                   first surface 
                 
                 
                   14 
                   second surface 
                   16 
                   first tang 
                 
                 
                   18 
                   second tang 
                   20 
                   tang height 
                 
                 
                   22 
                   link height 
                   24 
                   transverse hole 
                 
                 
                   26 
                   concrete 
                   28 
                   container 
                 
                 
                   30 
                   seam 
                   32 
                   reinforcing member 
                 
                 
                   34 
                   plate link 
                   36 
                   alternate sidewalk link 
                 
                 
                   40 
                   girder 
                   42 
                   truss 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The linking method of the present invention links precast concrete pieces together. It is necessary for the precast concrete pieces to include appropriate geometric features to enable the linking method to work. The drawing figures and the following detailed explanations explain some specific embodiments. Many other embodiments will be apparent to those skilled in the art. Thus, the illustrations and explanations should properly be viewed as exemplary and not limiting. 
         [0026]    One good application for the inventive method is the construction of concrete sidewalks.  FIG. 1  shows a precast concrete piece which is useful for this purpose. Sidewalk link  10  is preferably a rectangular piece having a suitable length and width. First surface  12  faces upward in the orientation shown in the view. First tang  16  extends out from a first end of the sidewalk link and second tang  18  extends out from the opposite end. 
         [0027]    Each of the two tangs is pierced by one or more transverse openings. In the embodiment shown, four transverse holes  24  pass through each tang. The openings need not be circular but may be any suitable shape. However, those skilled in the art will know that round holes are easy to cast in concrete. 
         [0028]    The tangs are approximately half as high as the sidewalk link in this embodiment. The reader will observe that tang height  20  is about ½ link height  22 .  FIG. 2  shows the same sidewalk link  10  in an inverted state. In this orientation second surface  14  is facing upward. The reader may see in this view how the transverse holes  24  pass all the way through the tangs. 
         [0029]      FIG. 3  is a detailed section view taken in the area of first tang  16 . Transverse hole  24  passes through the first tang and is radially symmetric about the central axis shown. In the orientation depicted, second surface  14  faces upward and first surface  12  faces downward. 
         [0030]      FIG. 4  shows two sidewalk links  10  in position for assembly. Second tang  18  of the right hand sidewalk link  10  is position to lie over first tang  16  of the left hand sidewalk link  10  when the right hand sidewalk link is placed in position. Once the right hand sidewalk link is placed, second surface  14  of the right hand sidewalk link will lie approximately flush with first surface  12  of the left hand sidewalk link. These surfaces then form the walking surface for the finished sidewalk.  FIG. 5  shows the assembly with the right hand link placed in the proper position. 
         [0031]    In the position shown in  FIG. 5 , the reader will note that the transverse holes  24  in the two overlapping tangs align. There will of course be some manufacturing and placement tolerances which prevent perfect alignment. The present inventive method does not need perfect alignment, so long as the transverse openings roughly align. 
         [0032]      FIG. 6  shows the linking process. A liquid material is deposited in each of the aligned transverse holes. This must be a “solidifying substance.” In this context, a solidifying substance is defined as a liquid that transitions to a solid over time, and which when solid has at least moderate resistance to shearing forces. Examples include concrete, reinforced grouts, epoxy resins, thermoset resins, moisture-cured resins, and UV-cured resins. It is even possible to use a flexible substance such as a two-part molding rubber. This is desirable where some small amount of movement is needed between adjoining links (such as to allow for frost expansion). 
         [0033]    Concrete is widely available and suitable for this purpose. Depending on the mechanical strength required and other environmental considerations (such as hard frosts, etc.), it may be desirable to add a fiber reinforcing material or a plasticizing material to the concrete. In the example of  FIG. 6 , container  28  contains freshly mixed concrete  26 . While the concrete is still wet, it is poured into transverse holes  24 . The concrete flows down into the transverse holes in both the overlapping tangs. 
         [0034]    The concrete solidifies over time. The result is shown in  FIG. 7 .  FIG. 8  shows a section view through the overlapping tangs after the concrete has solidified. Concrete  26  has formed a solid column that occupies the void previously existing within aligned transverse holes. The solid column of solidified concrete locks first tang  16  to second tang  18  and thereby locks the two sidewalk links together. 
         [0035]    Depending upon the amount of stress anticipated on the joint, it may be desirable to add a reinforcing member to the concrete. In  FIG. 8 , reinforcing member  32  (a piece of steel re-bar) has been placed within the concrete column prior to the time the concrete hardens. This is customarily done by pouring a portion of the necessary concrete, placing the reinforcing member in position, and pouring the remainder of the needed concrete. However, it is also possible to place the reinforcing member before any concrete is poured and it is even possible to place the reinforcing member into the wet concrete after it has been completely poured. 
         [0036]    A steel re-bar is used as the reinforcing member in  FIG. 8 . Other possibilities include a glass-reinforced plastic rod (suitable where a more elastic solidifying substance is used). A glass reinforced epoxy rod may also be used. 
         [0037]    The linking method may be used to tie together any desired number of precast concrete pieces.  FIG. 9  shows a sidewalk made using the method, in which five sidewalk links  10  have been tied together. 
         [0038]    As stated initially, the tang geometry shown in  FIGS. 1-8  is only one example of many possibilities.  FIG. 10  shows a second possibility. Two alternate sidewalk links  36  are shown. In this embodiment, only one of the two extending tangs is flush with second surface  14 . However, two adjoining sidewalk links fit together in a similar fashion as for the original embodiment. The two tangs still overlap and the transverse holes  24  still align. The adjoining links are fastened together by filling the aligned holes with a solidifying substance such as concrete. 
         [0039]    The exact shape and location of the tangs is not particularly important, as long as a transverse opening volume is created which—when filled with a solidifying substance—links the two pieces together. In fact, any type of interlocking feature which includes the transverse openings may be used. In this context, the term “interlocking feature” should be understood to mean any geometry which creates an overlap with the adjacent precast concrete piece. 
         [0040]    Of course, the precast concrete pieces that can be connected using the inventive method are by no means limited to sidewalk pieces.  FIG. 11  shows an application where the precast concrete pieces are much larger. Plate link  34  is a large, steel-reinforced floor section. Such a plate might be 3 meters long and 2 meters wide. 
         [0041]    Each plate link has a first tang  16  and a second tang  18  extending therefrom. Each tang has a plurality of transverse openings—in this case transverse holes  24 . The two tangs are overlapped so that the transverse holes align. A solidifying substance is then placed in the transverse openings and allowed to set. 
         [0042]      FIG. 12  shows adjacent structure which would typically be used to support precast pieces like the plate links. Girders  40  have attached trusses  42  spanning the gap in between. Plate links  34  are placed on top of these structures. Steel reinforcing members within the plate links may be attached to the girders or trusses to prevent unwanted movement. Once the plate links are arranged so that the tangs are overlapping, the solidifying substance is added to the transverse openings to lock the plate links together. 
         [0043]    Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. The inventive device could be realized in many different ways. Thus, the examples provided are properly viewed as embodiments of the invention rather than a definition of the invention's scope.