US Patent 7237282 Stackable and stable bedding foundation

A nestably stackable bedding foundation assembly replaces the traditional border wire and disposed coil spring foundation assembly in a so-called box spring. The foundation assembly may be nestably stacked with numerous other such assemblies for transportation, thereby avoiding the need to compress and tie the assembly for shipping. Each foundation assembly includes a number of corrugated support wires having alternating peaks and valleys. The valleys of selected support wires are twisted relative to their associated peaks to provide a more stable mounting to a base and offer a variety of firmness to specific zones of the assembly.