Joining system for fast assembly structures of variable size

Joining system for fast assembly structures of variable size which comprises polyhedron shaped connectors or nodes having 18 equal square faces, as well as eight regular triangular faces. In the square faces threaded round perforations are located having variable diameter according to side of the square, characterized in that it consists of spherical head screws having an integrated nut;

• an bushing having a reduced height cylindrical structure, with a semispherical cavity in the central part of one of the cylindrical structure faces and a divergent broaden section ending in the other cylindrical structure face. When the screw is in the assembled position, it is partially located inside the tubular element and the bushing is fixed to the extreme inner wall of said tubular element, protruding from the tube part of the screw body, the nut and the threaded section;
• the assembled spherical head freely rotates and the screw can effect shifts during its assembling stage, in a very wide angle value range of the tubular element with respect to the node, which are constructed with metallic or plastic materials.