Mattress spring structure

A mattress spring structure including a plurality of spring assemblies each comprising an array of open-ended spring coils, the spring assemblies being arranged in superimposed relationship with the individual spring coils of the respective assemblies registering in vertical alignment with one another, a membrane extending between each pair of superimposed assemblies and means connecting the assemblies to one another to form a unitary structure wherein all the coil springs are of a type having a tendency to incline in a preferential direction when subjected to axial loading, and wherein the coil springs in one assembly have opposite orientations to the coils in a superimposed assembly.