Multi-zone mattress

Abstract

A multi-zone mattress comprising a top layer, an intermediate layer and a bottom layer disposed in substantially parallel relationship relative to each other including a first plurality of zones each having a first firmness profile to support a person thereon separated by a second plurality of zones each having a second firmness profile less than the firmness of the first firmness profile of the first plurality of zones, the first plurality of zones and the second plurality of zones each cooperatively formed by corresponding sections of the top layer, intermediate layer and bottom layer disposed in substantially parallel alignment relative to each other.

Claims

1. A mattress comprising a top layer, an intermediate layer and a bottom layer disposed in substantially parallel relationship relative to each other including a first plurality of zones each having a first firmness profile to support a person thereon separated by a second plurality of zones each having a second firmness profile less than said firmness of said first firmness profile of said first plurality of zones, said first plurality of zones and said second plurality of zones each cooperatively formed by corresponding sections of said top layer, said intermediate layer and said bottom layer disposed in substantially parallel alignment relative to each other wherein said top layer comprises an outer upholstery or fabric panel and an inner fabric backing having a panel of resilient material disposed therebetween, said outer upholstery or fabric panel comprises a first plurality of sections including a proximal section, a middle section and a distal section separated by a second plurality of sections including a pair of interior sections, said first plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections having a second firmness profile less than said first firmness profile of said first plurality of sections.

2. The mattress of claim 1 wherein said intermediate support layer comprises an intermediate panel or block of resilient material.

3. The mattress of claim 2 wherein said bottom foundation layer comprises a foundation resilient base of coil springs arranged or disposed in rows and columns.

4. The mattress of claim 1 wherein said second plurality of sections further comprises a pair of exterior sections formed on each end portion of said top layer of said mattress.

5. The mattress of claim 1 wherein said intermediate support layer comprises a panel or block of resilient material comprising said first plurality of sections including a proximal section, a middle section and a distal section separated by said second plurality of sections including a pair of interior sections, said first plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections of said intermediate support layer having a second firmness profile less than the first firmness profile of said first plurality of sections of said intermediate support layer.

6. The mattress of claim 5 wherein said second plurality of sections of said intermediate support layer further comprises a pair of exterior sections formed on each end portion of said intermediate support layer of said mattress.

7. The mattress of claim 5 wherein said bottom foundation layer comprises a foundation resilient base comprising said first plurality of sections including a proximal section, a middle section and a distal section separated by said second plurality of sections including a pair of interior sections, said plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections of said bottom foundation layer having a second firmness profile less than the first firmness profile of the said first plurality of sections of said bottom foundation layer.

8. The mattress of claim 7 wherein said second plurality of sections of said bottom foundation layer may further comprises a pair of exterior sections formed on each end portion of said bottom foundation layer of said mattress.

9. The mattress of claim 7 wherein said proximal section of said top layer, said proximal section of said intermediate support layer and said proximal section of said bottom foundation layer cooperatively form a proximal support zone; said middle section of said top layer, said middle section of said intermediate support layer and said middle section of said bottom foundation layer cooperatively form a middle support zone and said distal section of said top layer, said distal section of said intermediate support layer and said distal section of said bottom foundation layer cooperatively form a distal support zone to form the said first plurality of zones having a first firmness profile to support a person on the mattress.

10. The mattress of claim 7 wherein corresponding interior sections of said top layer, said intermediate support layer and said bottom foundation layer cooperatively form corresponding second plurality of zones having a firmness profile less than the first firmness profile of said first plurality of zones.

11. The mattress of claim 1 wherein said proximal section, said intermediate section and said distal section of said top layer each comprises a separate panel of fabric having a weight or density greater than the weight or density of said separate panels forming said interior sections.

12. The mattress of claim 1 wherein said top layer comprises a single sheet of fabric having a second sheet of fabric sewn or otherwise held in place on said single sheet of fabric.

13. The mattress of claim 5 wherein said intermediate layer comprises a panel or block having a plurality of resilient projections extending upwardly from the upper surfaces of said interior sections.

14. The mattress of claim 7 wherein said bottom foundation layer comprises a plurality of coil springs arranged in columns, said coil springs of said first plurality of zones in adjacent rows are off-set to form a nested configuration and said plurality of coil springs of said interior sections are symmetrically arranged in rows and columns such that nested configurations are firmer than the symmetrically non-nested configurations to provide more support than the symmetrical non-nested configurations.

15. The mattress of claim 7 wherein said bottom foundation layer of said mattress comprises a plurality of symmetrically arranged coil springs, said coil springs of said proximal section, said middle section and said distal section are less resilient than said coil springs of said interior sections.

16. The mattress of claim 5 wherein said intermediate layer comprises a block of resilient material including a plurality of substantially convex resilient projections extending upwardly from said first plurality of sections and a plurality of substantially convex resilient projections extending upwardly from said second plurality of sections; an upper surface of said substantially convex resilient projections of said first plurality of sections being greater than said upper surfaces of said substantially convex resilient projections of said second plurality of sections.

17. The mattress of claim 16 wherein said a plurality of substantially convex resilient projections extending upwardly from said second plurality of sections are disposed in spaced relationship relative to each other.

18. The mattress of claim 5 wherein upper surfaces of said first plurality of sections of said intermediate layer are substantially flat and a plurality of resilient projections extend upwardly from said upper portions of said interior sections.

19. The mattress of claim 18 wherein adjacent resilient projections within each said interior section is separated by a trough and upper surfaces of said resilient projections are substantially flat.

20. A mattress comprising a top layer, an intermediate layer and a bottom layer disposed in substantially parallel relationship relative to each other including a second plurality of zones each having a first firmness profile to support a person thereon separated by a first plurality of zones each having a second firmness profile less than the firmness of said first firmness profile of said first plurality of zones, said first plurality of zones and said second plurality of zones each cooperatively formed by corresponding sections of said top layer, said intermediate layer and said bottom layer disposed in substantially parallel alignment relative to each other, said top layer comprises an outer upholstery or fabric panel and an inner fabric backing having a panel of resilient material disposed therebetween, said intermediate support layer comprises an intermediate panel or block of resilient material, said outer upholstery or fabric panel comprises a second plurality of sections including a proximal section, a middle section and a distal section separated by a first plurality of sections including a pair of interior sections, said first plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections having a second firmness profile less than said first firmness profile of said first firmness profile of said first plurality of sections, said intermediate support layer comprises a panel or block of resilient material comprising said second plurality of sections including a proximal section, a middle section and a distal section separated by said first plurality of sections including a pair of interior sections, said first plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections of said intermediate support layer having a second firmness profile less than first firmness profile of said first plurality of sections of said intermediate support layer, and said bottom foundation layer comprises a resilient base comprising said second plurality of sections including a proximal section, a middle section and a distal section separated by said first plurality of sections including a pair of interior sections, said plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections of said bottom foundation layer having a second firmness profile less than said first firmness profile of the said first plurality of sections of said bottom foundation layer.

21. The mattress of claim 16 wherein said intermediate layer comprises a block of resilient material including a plurality of substantially convex resilient projections extending upwardly from said first plurality of sections and a plurality of substantially convex resilient projections extending upwardly from said second plurality of sections; an upper surface of said substantially convex resilient projections of said first plurality of sections being greater than said upper surfaces of said substantially convex resilient projections of said second plurality of sections.

22. The mattress of claim 17 wherein said a plurality of substantially convex resilient projections extending upwardly from said second plurality of sections are disposed in spaced relationship relative to each other.

23. The mattress of claim 20 wherein said second plurality of sections of said intermediate support layer further comprises a pair of exterior sections formed on each end portion of said intermediate support layer of said mattress and said bottom foundation layer comprises a foundation resilient base comprising said first plurality of sections including a proximal section, a middle section and a distal section separated by said second plurality of sections including a pair of interior sections, said plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections of said bottom foundation layer having a second firmness profile less than the first firmness profile of the said first plurality of sections of said bottom foundation layer.

24. A mattress comprising a top layer, an intermediate layer and a bottom layer disposed in substantially parallel relationship relative to each other including a first plurality of zones each having a first firmness profile to support a person thereon separated by a second plurality of zones each having a second firmness profile less than the firmness of said first firmness profile of said first plurality of zones, said first plurality of zones and said second plurality of zones each cooperatively formed by corresponding sections of said top layer, said intermediate layer and said bottom layer disposed in substantially parallel alignment relative to each other wherein said top layer comprises an outer upholstery or fabric panel having a first plurality of sections including a proximal section, a middle section and a distal section separated by a second plurality of sections including a pair of interior sections, said first plurality of sections having a first firmness profile to support a person thereon and said second plurality of sections having a second firmness profile less than said first firmness profile of said first plurality of sections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a fuller understanding of the nature and object of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

(2) FIG. 1 is a cross-sectional side view of the multi-zone mattress of the present invention.

(3) FIG. 2 is an exploded cross-sectional side view of the multi-zone mattress of the present invention.

(4) FIG. 3 is a top view of the top layer of the multi-zone mattress of the present invention.

(5) FIG. 4 is a top view of an alternate embodiment of the top layer of the multi-zone mattress of the invention.

(6) FIG. 5 is a top view of the intermediate layer of the multi-zone mattress of the present invention.

(7) FIG. 6 is a top view of an alternate embodiment of the intermediate layer of the multi-zone mattress of the present invention.

(8) FIG. 7 is a top view of the bottom layer of the multi-zone mattress of the present invention.

(9) FIG. 8 is a top view of an alternate embodiment of the bottom layer of the multi-zone mattress of the present invention.

(10) FIG. 9 is an exploded cross-sectional side view of an alternate embodiment of the multi-zone mattress of the present invention.

(11) FIG. 10 is an exploded cross-sectional side view of another alternate embodiment of the multi-zone mattress of the present invention.

(12) FIG. 11 is an exploded cross-sectional side view of an alternate embodiment of the top layer of the multi-zone mattress of the present invention.

(13) FIG. 12 is an exploded cross-sectional side view of still another alternate embodiment of the multi-zone mattress of the present invention.

(14) Similar reference characters refer to similar parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

(15) The present invention relates to a multi-zone mattress comprising a plurality of first zones each having a first firmness profile to support a person thereon separated by a plurality of second zones each having a second firmness profile less than the firmness of the first firmness profile of the plurality of first zones wherein each of the plurality of first zones and each of the plurality of second zones each comprises multiple sections of different firmnesses to cooperatively form the plurality of first zones and the plurality of second zones.

(16) As shown in FIGS. 1 and 2, the multi-zone mattress generally indicated as 10 comprises a top layer generally indicated as 12, an intermediate layer generally indicated as 14 and a bottom layer generally indicated as 16 assembled together to form the multi-zone mattress 10.

(17) As shown in FIGS. 1 and 2, the top layer 12 comprises a quilted or outer upholstery panel generally indicated as 18 and an inner fabric backing generally indicated as 20 having a panel or block of resilient material generally indicated as 22 such as foam disposed therebetween. The top layer 14 comprises a first plurality of sections including a proximal section generally indicated as 24A, a middle section generally indicated as 24B and a distal section generally indicated as 24C separated by a second plurality of sections including a pair of interior sections each generally indicated as 26A. The first plurality of sections comprising sections 24A, 24B and 24C has a first firmness profile to support a person thereon and the second plurality of sections 26A has a second firmness profile less than the first firmness profile of the first plurality of sections 24A, 24B and 24C. In addition, the second plurality of sections may further comprise a pair of exterior sections each generally indicated as 26B formed or disposed on each end portion of the top layer 12 of the multi-zone mattress 10.

(18) As shown in FIGS. 1 and 2, the intermediate layer 14 comprises an intermediate block of resilient material such as foam comprising a first plurality of sections including a proximal section generally indicated as 28A, a middle section generally indicated as 28B and a distal section generally indicated as 28C separated by a second plurality of sections including a pair of interior sections each generally indicated as 30A. The first plurality of sections comprising sections 28A, 28B and 28C has a first firmness profile to support a person thereon and the second plurality of sections 30A has a second firmness profile less than the first firmness profile of the first plurality of sections 28A, 28B and 28C. In addition, the second plurality of sections may further comprise a pair of exterior sections each generally indicated as 30B formed or disposed on each end portion of the intermediate layer 14 of the multi-zone mattress 10.

(19) As shown in FIGS. 1 and 2, the bottom layer 16 comprises a resilient base such as a plurality of coil springs arranged or disposed in rows and columns comprising a first plurality of sections including a proximal section generally indicated as 32A, a middle section generally indicated as 32B and a distal section generally indicated as 32C separated by a second plurality of sections including a pair of interior sections each generally indicated as 34A. The first plurality of sections comprising sections 32A, 32B and 32C has a first firmness profile to support a person thereon and the second plurality of sections 34A has a second firmness profile less than the first firmness profile of the first plurality of sections 32A, 32B and 32C. In addition, the second plurality of sections may further comprise a pair of exterior sections each generally indicated as 34B formed on each end portion of the bottom base layer 16 of the multi-zone mattress 10.

(20) As shown in FIGS. 1 and 2, the proximal section 24A of the top layer 12, the proximal section 28A of the intermediate layer 14 and the proximal section 32A of the bottom layer 16 cooperatively form a proximal support zone generally indicated as 36A; the middle section 24B of the top layer 12, the middle section 28B of the intermediate layer 14 and the middle section 32B of the bottom layer 16 cooperatively form a middle support zone generally indicated as 36B; and the distal section 24C of the top layer 14, the distal section 28C of the intermediate layer 14 and the distal section 32C of the bottom layer 16 cooperatively form a distal support zone generally indicated as 36C to form the first plurality of zones having a first firmness profile to support a person on the multi-zone mattress 10.

(21) Similarly as shown in FIGS. 1 and 2, corresponding interior sections 26A of the top layer 12, interior sections 30A of the intermediate layer 14 and the interior sections 34A of the bottom layer 16 cooperatively form interior zones each generally indicated as 38A; while, corresponding exterior sections 26B of the top layer 12, exterior sections 30B of the intermediate layer 14 and the exterior sections 34B of the bottom layer 16 cooperatively form exterior zones generally indicated as 38B to form the second plurality of zones having a second firmness profile.

(22) FIG. 3 is a top view of the quilted or outer upholstery panel 18 of the top layer 12 of the multi-zone mattress 10. As depicted, the proximal section 24A, middle section 24B and distal section 24C of the quilted or outer upholstery panel 18 of the top layer 12 each includes a first pattern of stitching generally indicated as 40 denser than a second pattern of stitching generally indicated as 42 on the interior sections 26A and the exterior sections 26B such that the first plurality of sections 24A, 24B and 24C has the first firmness profile to support a person thereon and the second plurality of sections 26A and 26B has the second firmness profile less than the first firmness profile of the first plurality of sections 24A, 24B and 24C.

(23) FIG. 4 discloses an alternate embodiment of the quilted panel or outer upholstery panel 18 of the top layer 12 of the multi-zone mattress 10. Specifically, the proximal section 24A, middle section 24B and distal section 24C of the top layer 12 each comprises a separate panel of fabric having a weight or density greater than the weight or density of the separate panels forming the interior sections 26A and exterior sections 26B such that sections 24A, 24B, and 24C have a firmness profile greater than sections 26A and 26B to support a person thereon. Of course, the quilted panel or upholstery panel 18 of the top layer 12 may comprise a single sheet of fabric having a second sheet of fabric sewn or otherwise held in place on the single sheet of fabric to form sections 24A, 24B and 24C thicker than the single sheet of fabric such that sections 24A, 24B and 24C have a first firmness profile greater than the second firmness profile of sections 26A and 26B.

(24) The proximal section 24A, middle section 24B and distal section 24C may be a tighter weave than the weave of the interior sections 26A and 26B.

(25) As shown in FIGS. 2 and 5, the intermediate layer 14 of the multi-zone mattress 10 comprises a block of resilient material generally indicated as 44 such as foam. The substantially flat upper surfaces 49 of sections 28A, 28B and 28C each indicated as 46, and the upper surfaces of sections 30A and 30B each indicated as 48 are disposed in substantially the same horizontal plane. A plurality of substantially convex resilient projections each indicated as 50 extends upwardly from the upper portions of the interior sections 30A and the exterior sections 30B of the intermediate layer 14. As shown in FIG. 2, the resilient projections 50 may comprise a configuration similar to an egg carton. As shown in FIG. 1, the plurality of resilient projections 50 are depressed or flattened under the weight of a person on the multi-zone mattress 10.

(26) FIG. 6 shows an alternate embodiment of the intermediate layer 14 of the multi-zone mattress. In particular, the intermediate layer 14 of the multi-zone mattress 10 comprises a block generally indicated as 44 of resilient material such as foam. The upper surfaces 46 of sections 28A, 28B and 28C and the upper surfaces 48 of sections 30A and 30B are disposed in substantially the same plane. A plurality of recesses each indicated as 50 are formed in the upper portions of the interior sections 30A and the exterior sections 30B of the intermediate layer 14. The plurality of grooves or recesses 50 are depressed or flattened under the weight of a person on the multi-zone mattress 10.

(27) FIG. 7 is a top view of the bottom layer 16 of the multi-zone mattress 10. Specifically, the bottom layer 16 comprises a plurality of coil springs arranged in rows and columns. The coil springs of the proximal section 32A, middle section 32B and 32C of the bottom layer 16 generally indicated as 52 disposed in adjacent rows are off-set to form a nested configuration; while, the plurality of coil springs of the interior sections 34A and exterior sections 34B of the bottom layer 16 are symmetrically arranged in rows and columns generally indicated as 54. Such nested configurations are firmer than the symmetrical non-nested configurations to provide more support than the symmetrical non-nested configurations.

(28) FIG. 8 depicts a top view of an alternate embodiment of the bottom layer 16 of the multi-zone mattress 10 comprising a plurality of coil springs. The symmetrically arranged or configured coil springs of the proximal section 32A, middle section 32B and distal section 32C generally indicated as 52 are less resilient or stiffer than the symmetrically arranged or configured coil springs of the interior sections 34A and the exterior sections 34B. The differences in resilience or stiffness is the coil springs 52 of the proximal section 32A, middle section 32B and distal section 32C and the coil springs 54 of the interior sections 34A and exterior sections 34B are due to differences in thickness or gauge of the coils, tempering of the coils or material of the coils as well as other factors generally known in the art.

(29) Except for the intermediate layer 14, FIG. 9 shows an alternate embodiment of the multi-zone mattress 10 virtually the same as the multi-zone mattress 10 of FIGS. 1 and 2. As such, corresponding structural elements are similarly designated. As depicted, the intermediate layer 14 of the multi-zone mattress 10 comprises a block generally indicated as 44 of resilient material such as foam. The upper surfaces of sections 28A, 28B and 28C each generally indicated as 46 and the upper surfaces of sections 30A and 30B each generally indicated as 48 are disposed in substantially the same horizontal plane. A plurality of substantially convex resilient projections each indicated as 49 extends upwardly from the upper portions of sections 28A, 28B and 28C of the intermediate layer 14. Similarly, a plurality of substantially convex resilient projections each indicated as 50 extends upwardly from the upper portions of the interior sections 30A and exterior sections 30B of the intermediate layer 14. Projections 49 are larger than projections 50. In addition, projections 50 may be disposed in spaced relationship relative to each other. Thus, in the aggregate, the upper surfaces of the substantially convex resilient projections 49 for each section 28A, 28B and 28C are greater than the upper surfaces of the substantially convex resilient projections 50 for each section 30A and 30B. Thus sections 28A, 28B and 28C are firmer or less resilient than sections 30A and 30B.

(30) Except for the intermediate layer 14, FIG. 10 shows another alternate embodiment of the multi-zone mattress 10 virtually the same as the multi-zone mattress 10 of FIGS. 1 and 2. As such, corresponding structural elements are similarly designated. As depicted, the intermediate layer 14 of the multi-layer mattress 10 comprises a block generally indicated as 44 of resilient material such as foam. The upper surfaces of sections 28A, 28B and 28C each generally indicated as 46 and the upper surfaces of sections 30A and 30B each generally indicated as 48 are disposed in substantially the same horizontal plane. The upper surfaces 49 of sections 28A, 28B and 28C of the intermediate layer 14 are substantially flat. A plurality of resilient projections each indicated as 50 extends upwardly from the upper portions of the interior sections 30A and exterior sections 30B of the intermediate layer 14. Each resilient projection 50 of each section 30A and 30B comprises a substantially flat upper surface. Adjacent resilient projections 50 within each section 30A and 30B are separated by a trough 51. In other words, the resilient projections 50 may be disposed in spaced relationship relative to each other. Thus, the area of substantially flat upper surfaces 49 for each section 28A, 28B and 28C are greater than the upper surfaces of the resilient projections 50 of each section 30A and 30B. Thus sections 28A, 28B and 28C are firmer or less resilient than sections 30A and 30B.

(31) FIG. 11 depicts an alternate embodiment of the quilted top layer 12. Specifically, the quilted top layer 12 comprises an outer upholstery or fabric panel generally indicated as 18 and an inner fabric backing generally indicated as 20 having a block of resilient material generally indicated as 22 such as foam disposed therebetween. The quilted top layer 12 comprises a first plurality of sections including a proximal section generally indicated as 24A, a middle section generally indicated as 24B and a distal section generally indicated as 24C separated by a second plurality of sections including a pair of interior sections each indicated as 26A. In addition, the second plurality of sections may further comprise a pair of exterior sections each indicated as 26B formed on opposite ends of the quilted top layer 12. The substantially flat upper surfaces 49 of the block of resilient material of the first plurality comprising sections 24A, 24B and 24C have a first firmness profile greater than the second firmness profile of the substantially convex projections 50 of sections 26A and 26B of the second plurality of sections to support a person thereon.

(32) FIG. 12 shows an alternate embodiment of the multi-zone mattress 10. Specifically, the top layer 12 comprises a quilted or outer upholstery panel generally indicated as 18 and an inner fabric backing generally indicated as 20 having a panel or block of resilient material generally indicated as 22 such as foam disposed therebetween.

(33) The top layer 14 comprises a first plurality of sections including a proximal exterior section 24A, a proximal interior section 24B, a distal interior section 24C and a distal exterior section 24D and a second plurality of sections including a proximal section 26A, a middle section 26B and a distal section 26C. The first plurality of sections comprising sections 24A, 24B, 24C and 24D has a first firmness profile and the second plurality of sections comprising sections 26A, 26B and 26C has a second firmness profile less than the first firmness profile of the first plurality of sections 24A, 24B, 24C and 24D.

(34) As shown in FIG. 12, the intermediate support layer 14 comprises an intermediate block of resilient material generally indicated as 44 such as foam comprising a first plurality of sections including a proximal exterior section 28A, a proximal interior section 28B, a distal interior section 28C and a distal exterior section 28D and a second plurality of sections including a proximal section 30A, a middle section 30B and a distal section 30C. The first plurality of sections comprising sections 28A, 28B, 28C and 28D has a first firmness profile and the second plurality of sections comprising sections 30A, 30B and 30C has a second firmness profile less than the first firmness profile of the first plurality of sections 28A, 28B, 28C and 28D.

(35) As shown in FIG. 12, the bottom layer 16 comprises a resilient base such as a plurality of coil springs arranged or disposed in rows and columns comprising a first plurality of sections including a proximal exterior section 32A, a proximal interior section 32B, a distal interior section 32C and a distal exterior section 32D and a second plurality of sections including a proximal section 34A, a middle section 34B and a distal section 34C. The first plurality of sections comprising sections 32A, 32B, 32C and 32D has a first firmness profile and the second plurality of sections 34A, 34B and 34C has a second firmness profile less than the first firmness profile of the first plurality of sections 32A, 32B, 32C and 32D.

(36) The top layer 12 of the multi-zone mattress 10 of the alternate embodiment shown in FIG. 12 may comprise any of the embodiments previously described.

(37) The intermediate layer 14 of the multi-zone mattress 10 of the embodiment in FIG. 12 may comprise any of the embodiments previously described.

(38) The bottom layer 16 of the multi-zone mattress 10 of the alternate embodiment shown in FIG. 12 may comprise any of the embodiments previously described.

(39) The first plurality of zones comprises the proximal exterior zone 36A formed by the proximal exterior section 24A of the top layer 12, the proximal exterior section 28A of the intermediate layer 14 and the proximal section 32A of the bottom layer 16; a proximal interior zone 36B formed by the proximal interior section 24B of the top layer 12, the proximal interior section 28B of the intermediate layer 16 and the proximal interior section 32B of the bottom layer 16; a distal interior zone 36C formed by the distal interior section 24C of the top layer 12, the distal interior section 28C of the intermediate layer 14 and the distal interior section 32C of the bottom layer 16 and a distal interior zone 36D formed by the distal exterior section 24D of the top layer 12, the distal exterior section 28D of the intermediate layer 14 and the distal exterior section 32D of the bottom layer 16.

(40) The second plurality of zones comprises a proximal zone 38A comprising the proximal section 26A of the top layer 12, the proximal section 30A of the intermediate layer 14 and the proximal section 34A of the bottom layer 16; a middle zone 38B comprising the middle section 26B of the top layer 12, the middle section 30B of the intermediate layer 14 and the middle section 34B of the bottom layer 16; and a distal zone 38C comprising the distal section 26C of the top layer 12, the distal section 30C of the intermediate layer 14 and the distal section 34C of the bottom layer 16.

(41) It will thus be seen that the objects set forth above, among those made apparent from the preceding description are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

(42) It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

(43) Now that the invention has been described,