Anatomical, pressure-evenizing mattress overlay with prestressed core, and baffled, lateral-edge core respiration

Abstract

An anatomical pressure-evenizing mattress overlay including a dynamic-response core having spaced, upper and lower, surfaces and an intermediate, perimetral edge. The core is formed including a 100% open-cell, compressible and flowable, viscoelastic foam expanse, and possesses a relaxed-state volume which resides in about an 8-10% nominally compressed condition. Load-transmissively bonded to the entire outside of the core, so as to function as a dynamically-responsive unit with it, and possessing a relaxed-state, internal, prestressed, tension condition, is an elastomeric, moisture- and gas-flow-managing coating, including fluid-flow-controlling, baffled, respiration window structure which exposes a portion of the core's edge to accommodate respiration of and for the interior of the core.

1 . An anatomical pressure-evenizing mattress overlay comprising
 a dynamic-response core expanse having spaced, upper and lower, surfaces and a perimetral edge extending between said surfaces, formed of a 100% open-cell, compressible and flowable, viscoelastic foam, and having a relaxed-state volume in the overlay which is prestressed, and about 8-10% compressed, thus to create a pre-compression condition in the expanse, and   an elastomeric, moisture- and gas-flow-managing coating, including respiration window structure operatively associated with said core expanse's said perimetral edge, load-transmissively bonded to the entirety of the outside of said expanse to function as a dynamically-responsive unit with the expanse, and possessing a relaxed-state, internal, prestressed, tension condition.   
     
     
         2 . The overlay of  claim 1 , wherein said core expanse is elongate and includes opposite ends, and said respiration window structure includes a pair of laterally baffled windows disposed, one each, adjacent said core expanse's said opposite ends. 
     
     
         3 . The overlay of  claim 2 , wherein the lateral baffling for said windows includes, suitably anchored to said coating, and for each window, (a) a pair of laterally spaced, outwardly projecting baffle filter blocks disposed adjacent laterally opposite sides of the window and formed of the same viscoelastic foam material which is employed in said core expanse, and (b) an expanse of transparent adhering tape bridging the space between said blocks, and anchoring the blocks to said coating via attachment of the tape both (1) to portions of said blocks and (2) to portions of said coating which overlie the upper and lower surfaces of said core expanse adjacent the window. 
     
     
         4 . The overlay of  claim 3 , wherein each pair of baffle filter blocks and the associated adhering tape define an enclosed baffle chamber in fluid communication with the associated window. 
     
     
         5 . The overlay of  claim 3 , wherein each of said core expanse's said upper and lower surfaces has an area A, and said two windows collectively have an area which is approximately 0.0013 A. 
     
     
         6 . The overlay of claim in  1 , wherein said respiration window structure includes a perimetral band of thinness in said coating extending around the perimetral edge of said core expanse generally centrally intermediate the core expanse's said upper and lower surfaces, said band being edge-defined by spaced, upper and lower, baffle-function edges formed in thicker regions in said coating. 
     
     
         7 . The overlay of  claim 1 , wherein said core expanse exhibits a compressive-deflection vs. compression-force curve which includes an extremely linear region over which a relatively wide change in compressive deflection is accompanied by what turns out to be an anatomically insignificant change in compression pressure. 
     
     
         8 . The overlay of  claim 1 , wherein said core expanse is specifically formed of a polyurethane material. 
     
     
         9 . The overlay of  claim 1 , wherein said upper and lower surfaces are, allover, substantially equidistant. 
     
     
         10 . The overlay of  claim 1 , wherein said expanse has a thickness throughout of about 1-inches. 
     
     
         11 . The overlay of  claim 1 , wherein said expanse has opposite broad faces linked by a perimetral edge, and said coating, where it covers said broad faces, is formed so as to be substantially both moisture-impervious and gas-impermeable, and where it covers said edge so as to be, at least in its included respiration window structure, both moisture-resistant (but moisture-pervious) and gas-permeable. 
     
     
         12 . The overlay of  claim 11 , wherein said coating throughout possesses a plurality of approximately 0.001-inches thick sublayers including next-adjacent sublayers joined though initially wet, interfacial surfaces of joinder. 
     
     
         13 . The overlay of  claim 1 , wherein said coating has an outer surface which is characterized by an overall distribution of suction-cup-like dimples. 
     
     
         14 . An anatomical pressure-evenizing mattress overlay comprising
 a core expanse of single-density, 100%, open-cell, compressible and flowable, polyurethane, viscoelastic foam, and   an at least partially gas-breathable, elastomeric coating extending over the entirety of the surface area of said core expanse, and interfacially, mechanically bonded to said surface area, said coating being everywhere in tension and placing said core expanse everywhere in compression.   
     
     
         15 . An anatomical pressure-evenizing mattress overlay comprising
 a prestressed, dynamic-response core assembly having spaced, upper and lower, surfaces and a perimetral edge extending between said surfaces, formed with (a) a first core expanse made of a 100% open-cell, compressible and flowable, viscoelastic foam disposed adjacent said upper surface, (b) a second core expanse made of a different, closed-cell, viscoelastic foam disposed adjacent the opposite side of said first core expanse relative to said upper surface, and (c) a third core expanse made of yet another, closed-cell, viscoelastic foam disposed adjacent said core assembly's lower surface and the opposite side of said second core expanse relative to said first core expanse,   said core assembly having a relaxed-state volume in the overlay which is prestressed, and about 8-10% compressed, thus to create a pre-compression condition in the core assembly, and   an elastomeric, moisture- and gas-flow-managing coating, including respiration window structure operatively associated with said core assembly's said perimetral edge, load-transmissively bonded to the entirety of the outside of said assembly to function as a dynamically-responsive unit with the assembly, and possessing a relaxed-state, internal, prestressed, tension condition.