Box spring assembly

Claim 1

A spring assembly comprising a border wire to which are attached transversely and longitudinally extending pairs of crossing wires welded at their intersections, said pairs of crossing wires defining seats for attachment thereto of the end loops of coil springs characterized in that at least two opposed wires of the seats contain longitudinally spaced deviations in planes perpendicular to the seats which define in conjunction with the portions of the wire therebetween vertically spaced and longitudinally spaced bearing surfaces and the end loops contain diametrically disposed deviations of such configuration as to require relative deformation of the wires of the seat and the end loops to be interengaged and to become locked by restoration to their undeformed state and wherein the deviations in the end loops lie in the planes of the end loops such that when the end loops are sprung into engagement with the wires, the arcuate portions of the end loops pass through the deviations in the wires from one side and the deviating portions of the end loops pass between the deviations in the wires from the other side in engagement with the vertically and longitudinally spaced bearing surfaces provided by said deviating and nondeviating portions of the wires so as to prevent relative movement of the end loops perpendicularly and parallel to the plane of the grid.