Connection surface for a structural unit

Abstract

A connection surface that is disposed on at least a portion of a face of a structural unit comprises a first convex surface and a first concave surface arranged substantially along a first line. The shape of the first concave surface is complementary to the shape of the first convex surface. A second convex surface and a second concave surface are arranged substantially along a second line that is substantially parallel to the first line. The shape of the second concave surface is complementary to the shape of the second convex surface. The concave-convex order of the second line is reversed relative to the first line, such that the second convex surface corresponds with the first concave surface and the second concave surface corresponds with the first convex surface.

What is claimed is: 
     
         1 . A connection surface disposed on a face of a structural unit, the connection surface comprising:
 a first convex surface and a first concave surface, the first convex surface and first concave surface being arranged substantially along a first line, the shape of the first concave surface being complementary to the shape of the first convex surface; and   a second convex surface and a second concave surface, the second convex surface and second concave surface being arranged substantially along a second line that is substantially parallel to the first line, the shape of the second concave surface being complementary to the shape of the second convex surface;   wherein a concave-convex order of the second line is reversed relative to the first line such that the second convex surface corresponds to the first concave surface and the second concave surface corresponds to the first convex surface.   
     
     
         2 . The connection surface of  claim 1  wherein the first and second convex surfaces and first and second concave surfaces each comprise at least one partial geometric solid. 
     
     
         3 . The connection surface of  claim 1  wherein the first convex and second concave surfaces together define a third S profile, and wherein the second concave and first convex surfaces together define a fourth S profile that is symmetrical but reversed with respect to the third S profile. 
     
     
         4 . The connection surface of  claim 3  wherein the profile of the first and second S profiles is different from the profile of the third and fourth S profiles. 
     
     
         5 . The connection surface of  claim 1  wherein the first convex surface and first concave surface are separated by a first distance, and wherein the second concave and second convex surfaces are separated by a second distance. 
     
     
         6 . The connection surface of  claim 5  wherein the second distance is substantially equal to the first distance. 
     
     
         7 . The connection surface of  claim 6  wherein the first and second lines are separated by a third distance that is substantially equal to the first distance. 
     
     
         8 . A structural unit comprising:
 a plurality of faces;   at least one connection surface disposed on each of at least two of the plurality of faces;   wherein each connection surface comprises:   a first convex surface and a first concave surface, the first convex surface and first concave surface being arranged substantially along a first line, the shape of the first concave surface being complementary to the shape of the first convex surface; and   a second convex surface and a second concave surface, the second convex surface and second concave surface being arranged substantially along a second line that is substantially parallel to the first line, the shape of the second concave surface being complementary to the shape of the second convex surface;   wherein a concave-convex order of the second line is reversed relative to the first line such that the second convex surface corresponds to the first concave surface and the second concave surface corresponds to the first convex surface.   
     
     
         9 . The structural unit of  claim 8  wherein the structural unit comprises a molded concrete building unit. 
     
     
         10 . The structural unit of  claim 8  wherein the unit has a first and opposite second face, each said face having a connection surface thereon. 
     
     
         11 . The structural unit of  claim 10  where the first and second faces are substantially parallel. 
     
     
         12 . The structural unit of  claim 10  wherein the unit first and second faces are not substantially parallel. 
     
     
         13 . A structure comprising:
 a plurality of structural units including at least first and second structural units, each of the plurality of structural units comprising a plurality of faces including at least a first and second face, each of said first and second faces having at least one connection surface;   wherein each connection surface comprises:   a first convex surface and a first concave surface, the first convex surface and first concave surface being arranged substantially along a first line, the shape of the first concave surface being complementary to the shape of the first convex surface; and   a second convex surface and a second concave surface, the second convex surface and second concave surface being arranged substantially along a second line that is substantially parallel to the first line, the shape of the second concave surface being complementary to the shape of the second convex surface;   wherein a concave-convex order of the second line is reversed relative to the first line such that the second convex surface corresponds to the first concave surface and the second concave surface corresponds to the first convex surface;   wherein connection surfaces of the first and second structural units are coupled to one another such that the first and second concave surfaces of the connection surface of the first structural unit at least partially receive the first and second convex surfaces of the connection surface of the second structural unit, and such that the first and second concave surfaces of the connection surface of the second structural unit at least partially receive the first and second convex surfaces of the connection surface of the first structural unit.   
     
     
         14 . The structure of  claim 13  wherein the connection surfaces are coupled to one another such that the first and second structural units are constrained from either horizontal or vertical movement with respect to one another, but are less constrained for the other of horizontal or vertical with respect to one another. 
     
     
         15 . The structure of  claim 13  wherein a gap is defined between mating faces of the first and second structural units that is permeable to liquid. 
     
     
         16 . The structure of  claim 13  wherein the connection interface between the first and second structural units is substantially impermeable to light, sand and soil. 
     
     
         17 . The structure of  claim 13  wherein the first and second structural units are of different sizes and/or different shapes. 
     
     
         18 . The structure of  claim 13  wherein the structure comprises at least a third structural unit;
 wherein the third structural unit comprises at least two connection surfaces on a single face; 
 wherein connection surfaces of the first and second structural units are coupled to respective ones of the at least two connection surfaces on the third structural unit.