Abstract: An adjustable mattress may have an inner spring core between a top and bottom cover. The bottom cover may have at least one section made of a stretchable material that stretches around the mattress as it bends. The stretchable cover reduces the stress on the inner core for the bending when adjusting the mattress. The inner core may be formed from a spring array surrounded by a foam perimeter rail. Sides of the foam perimeter rail may be formed from individual foam coils.

Abstract: A mattress has a perimeter rail having a head end, a foot end, and two sides, each having an inner surface, and at least two substantially parallel rectilinear sections. Each section comprises an array of springs whose tension is selected to provide a predetermined firmness for that section. Each adjacent pair of sections is urged into a spaced-apart relationship by a spacing means, where each spacing means comprises a flexible spacer. The flexible spacer restricts or substantially eliminates the translation of movements between the sections of the mattress, while avoiding the use of uncomfortable separation means.