Method of making a mattress overlay

Abstract

A method of making a polyurethane foam mattress overlay so that it has several sections defined in a relatively flat support surface thereof. The sections are longitudinally disposed so as to correspond with different parts of a user's body. Each such section has predetermined support characteristics which are selected in relationship with such characteristics for the other sections so as to define systematized support. Specific numerical ranges and interrelationships for such sections are preferred. A plurality of projections are formed in each surface section. In general, the cross-sectional area of such projections at the overlay support surface or at a given depth therefrom is the same within each section, but differs from one section to another. Separation distances between such projections may also vary with the respective sections. The resulting tailored support characteristics in respective sections provide engineered support for all parts of a user's body. Side edges of the projections may be bevelled and/or include a radius of curvature to enhance independent action of the projections. Channels for dissipating heat and moisture may be provided, and have characteristics which vary with the different support sections. An effectiveness index takes into consideration the thickness, indentation load deflection (i.e., stiffness), and density of a given pad, to assist practioners in selecting appropriate embodiments of the invention.