Tension relieving body support apparatus
A mattress including a core foam layer having a first indentation force deflection at twenty five percent compression, a first density and a first thickness. The top outer foam layer has a second indentation force deflection at twenty five percent compression, a second density and a second thickness. The first intermediate foam layer is intermediate and coextensive with the core layer and the top outer layer, and has a third indentation force deflection at twenty five percent compression, a third density and a third intermediate thickness. The first indentation force deflection is greater than the third indentation force deflection and the third indentation force deflection is greater than the second indentation force deflection.
1. A mattress comprising:
a core foam layer having a first indentation force deflection at twenty five percent compression, a first density and a first thickness;
a top outer foam layer having a second indentation force deflection at twenty five percent compression, second density and a second thickness;
a first intermediate foam layer intermediate and coextensive with the core layer and the top outer layer and bonded to the core layer and the top outer layer; and having a third indentation force deflection at twenty five percent compression, a third density and a third intermediate thickness;
wherein the first indentation force deflection is greater than the third indentation force deflection and the third indentation force deflection is greater than the second indentation force deflection; and
wherein the relationship of first indentation force deflection, second indentation force deflection and third indentation force deflection is defined by the relationships:
A =( C/ 5.3)plus or minus 5
B= 2( C/ 5.3)plus or minus 5
wherein A represents the second indentation force deflection, B represents the third indentation force deflection and C represents the first indentation force deflection.
2. The mattress of claim 1 , wherein C equals 80 plus or minus 5.
3. The mattress of claim 1 , wherein the core foam layer comprises polyurethane and wherein the first density is between about 2.5 pounds per cubic foot and about 3.0 pounds per cubic foot and the first indentation force deflection is from about 75 to about 90 and the first thickness is from about one half inch to about five inches.
4. The mattress of claim 1 , wherein the intermediate foam layer comprises polyurethane wherein the third density is between about one and one half pounds per cubic foot and about two and one half pounds per cubic foot and the third indentation force deflection is from about twenty five to about thirty five and the third thickness is from about one half inch to about three inches.
5. The mattress of claim 1 , wherein the top outer foam layer comprises polyurethane, latex or a combination thereof and wherein the second density is from about two and three quarters to four and one half pounds per cubic foot, the second indentation force deflection is from about ten to twenty and the second thickness is from about one half to about three inches.
6. The mattress of claim 1 , wherein the top outer foam layer has a softness compression modulus of about 1.75 to about 2.35.
7. The mattress of claim 1 , wherein the first intermediate foam layer has a support compression modulus of about 1.7 to about 2.6.
8. The mattress of claim 1 , wherein the core layer has a support compression modulus of about 1.9 to about 2.3.
9. The mattress of claim 1 , further comprising a bottom outer foam layer and second intermediate foam layer intermediate and coextensive with the core layer and the bottom outer layer.
10. The mattress of claim 1 , wherein the bottom outer foam layer has the second indentation force deflection at twenty five percent compression and the second density and the second intermediate foam layer has the third indentation force deflection at twenty five percent compression and the third density.
11. A method of making a mattress comprising:
bonding a core foam layer having a first indentation force deflection at twenty five percent compression, a first density and a first thickness to a first intermediate foam layer that is substantially coextensive with the core layer;
bonding a top outer foam layer to the first intermediate foam layer;
selecting the top outer foam layer to have a second indentation force deflection at twenty five percent compression, second density and a second thickness;
selecting the intermediate layer to have a third indentation force deflection at twenty five percent compression, a third density and a third intermediate thickness;
wherein the first indentation force deflection is greater than the third indentation force deflection and the third indentation force deflection is greater than the second indentation force deflection; and
selecting the relationship of first indentation force deflection, second indentation force deflection and third indentation force deflection to be defined by the relationships
A =( C/ 5.3)plus or minus 5
B = 2( C/ 5.3)plus or minus 5
wherein A represents the second indentation force deflection, B represents the third indentation force deflection and C represents the first indentation force deflection.
12. The method of claim 11 , further comprising selecting the first indentation force deflection such that C equals 80 plus or minus 5.
13. The method of claim 11 , further comprising selecting the core foam layer to comprise polyurethane and such that the first density is between about 2.5 pounds per cubic foot and about 3.0 pounds per cubic foot, the first indentation force deflection is from about 75 to about 90 and the first thickness is from about one half inch to about five inches.
14. The method of claim 11 , further comprising selecting the intermediate foam layer to comprise polyurethane and such that the third density is between about one and one half pounds per cubic foot and about two and one half pounds per cubic foot, the third indentation force deflection is from about twenty five to about thirty five and the third thickness is from about one half inch to about three inches.
15. The method of claim 11 , further comprising selecting the top outer foam layer to comprise polyurethane, latex or a combination thereof and such that the second density is from about two and three quarters to four and one half pounds per cubic foot, the second indentation force deflection is from about ten to twenty and the second thickness is from about one half to about three inches.
16. The method of claim 11 , further comprising selecting the top outer foam layer to have a softness compression modulus of about 1.75 to about 2.35.
17. The method of claim 11 , further comprising selecting the first intermediate foam layer to have a support compression modulus of about 1.7 to about 2.6.
18. The method of claim 11 , further comprising selecting the core layer to have a support compression modulus of about 1.9 to about 2.3.
19. The method of claim 11 , further comprising bonding a second intermediate foam layer to the core foam layer and bonding a bottom outer foam layer to the intermediate foam layer such that the second intermediate foam layer is intermediate between and coextensive with the core layer and the bottom outer layer.
20. The method of claim 11 , further comprising selecting the bottom outer foam layer to have the second indentation force deflection at twenty five percent compression and the second density and selecting the second intermediate foam layer to have the third indentation force deflection at twenty five percent compression and the third density.