WO2000065962A1

WO2000065962A1 - Composite foam mattress having multiple laminate construction

Info

Publication number: WO2000065962A1
Application number: PCT/US2000/012411
Authority: WO
Inventors: Peter O. Frickland; James E. Marson
Original assignee: Cascade Designs Inc
Current assignee: Cascade Designs Inc
Priority date: 1999-05-05
Filing date: 2000-05-05
Publication date: 2000-11-09
Anticipated expiration: 2001-11-05
Also published as: WO2000065962A9; AU4990700A

Abstract

A compressible pad having a resilient core (40) wholly surrounded by and bonded to an upper layer (20) and a lower layer (30) of less resilient material wherein the upper and lower layers are bonded at their common perimeter to form an enclosed member. In one embodiment, a plurality of slits (28) are formed in one layer to permit passive ingress and egress of air into and from the void occupied by the core. In another embodiment, a valve is disposed between the environment and the core to permit air ingress and egress. Features of the invention include the formation of contours (12) on the upper and/or lower surface of the pad to alter the deflection properties of the pad, and/or facilitate storage of the pad or inflation of the pad. Preferably, the upper and lower layers are constructed from a closed cell foam and the core is constructed of an open cell foam.

Description

COMPOSITE FOAM MATTRESS HAVING MULTIPLE LAMINATE

CONSTRUCTION

Field of the Invention: The present invention pertains to the field of self-inflating ground pads, and more particularly to those having a multiple laminate foam construction.

Background of the Invention:

In the field of ground pads, there have traditionally been two distinct avenues for achieving the desired combination of suitable support, insulative characteristics, and desirable storage dimensions. The first avenue arrived shortly after the introduction of foamed polymers into the market place. These pads consisted mainly of a slab of closed cell foam material that could be conveniently rolled into a storable form. Subsequently, these pads were enhanced by incorporating features or protrusions on the upper surface of the slab. Nevertheless, these pads have remained essentially unchanged since their introduction.

The second avenue arrived during the early 1970's. This second approach to ground pads utilized a highly compressible foam slab to which was bonded to an airtight skin. A valve was placed so that the interior chamber defined by the skin would be in fluid communication with the environment. Thus, when it was desired to inflate the pad, the user need only open the valve to permit the uncompressing foam to draw air into the chamber. When the pad was fully inflated, the user closed the valve to maintain the air volume in the pad. Because the volume was constant, and the pad shape retained by the bonding of the skin to the foam, localized compression of one portion of the pad would increase overall internal air pressure without the traditional air mattress bulging in uncompressed sections. For a more detailed review of this technology, reference is made to United States Patent numbers 3,872,525; 4,624,877; and 4,205,974 and for purposes of this patent, are incorporated by reference herein.

Each field of pad technology has its strengths: closed cell foam pads are highly durable in that they are not easily torn and if punctured, have no noticeable decrease in performance, stow easily, and are light in weight; self-inflating pads as described above are very comfortable, easily compressible and stow easily. However, closed cell foam pads are not inherently comfortable and self-inflating pads are not highly durable and are often noticeably more expensive to manufacture than closed cell foam pads.

Another line of pads is also used, although their use in the field of outdoor recreation has been more limited. These pads utilize one or more foam slabs surrounded by, but not bonded to, a fabric shell. In this respect, these pads resemble certain traditional household mattresses. While these pads are rather inexpensive to manufacture and are considered to be comfortable, they provide little resistance to water absorption, do not stay compressed for storage without an auxiliary compression strap system, and are not durable when compared to other technologies such as closed cell foam products. Water absorption in particular can make the pads cold and noninsulating while making them heavier to carry. Both are highly undesirable features in a ground pad used for hiking and mountaineering.

Therefore, the primary objectives for a ground pad have been achieved with mixed success. Traditional performance pads might have good insulating properties, be highly durable and low in weight, and have low manufacturing cost, however these goals are usually achieved at the expense of user comfort. Conversely, comfortable performance pads may also have good insulating properties and compactability, however, these goals are usually achieved at the expense of manufacturing cost, puncture susceptibility, and increased weight. It is therefore desirable to develop a ground pad that has the advantages of a closed cell foam pad with the primary advantage of comfort associated with a self-inflating pad. The present invention is intended to meet these objectives.

SUMMARY OF THE INVENTION The present invention combines the desirable qualities of traditional closed cell foam pads with the advantages inherent in a self-inflating pad. By [SMEijbonding a shell of resilient material to a slab of resilient material having a density less than the shell, and by permitting the ingress and egress of air into and out of the chamber defined by the shell, the stated objective can be achieved. Broadly stated, a pad according to the invention comprises a first outer layer constructed from a first type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; a second outer layer constructed from a second type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; and an inner layer constructed from a third type of resilient material which defines a first major surface, a second major surface, and a perimeter portion wherein the inner layer is disposed between and permanently bonded at least in part to the inner surface of the first outer layer and the inner surface of the second outer layer. Preferably, the perimeter portions of the first and second outer layers are bonded to one another to form a substantially fluid tight seal, thereby shielding the inner layer from exposure to the elements. To permit fluid ingress and egress into the chamber defined by the first and second outer layers, the invention may be fitted with a valve closable at user discretion, or one or more apertures may be formed in either outer layer to permit passive ingress and egress of fluid into and out of the chamber. In a preferred embodiment, the inner layer is constructed of a foamed thermoset polymeric material having a stiffness of between about 10 and 45 lb 25% IFD and a density of between about 0.7 and 2.5 lbs/ft³, and preferably having a stiffness of between about 30 and 40 lb 25% IFD and a density of between about 1.0 and 1.7 lbs/ft³. Sectional thickness of the inner layer can range between about 0.25" to 4", and preferably between about 1.0" and 1.75". Best results have been achieved using an open cell, flexible, slabstock polyurethane foam.

Those persons skilled in the art will appreciate that the nature of the core is not essential to the invention insofar as any compliant or resilient material of homogenous or heterogeneous composition that provides a desirable level of stiffness, resilience, compressibility, and insulative characteristics will suffice. Thus, by way of example only, the core can be comprised of discrete portions having differing 25% IFD values such as is described in United States Patent number 5,282,286, which is incorporated herein by reference; it can be contoured prior to any thermoforming or subsequent fabrication steps as detailed below; it can be modified as described in United States Patent number 5,705,252, which is also incorporated herein by reference. Also in a preferred embodiment, the first outer layer (for convention purposes the upper layer which contacts a user) is constructed of a closed cell foamed thermoplastic polymeric material having a density of between about 0.5 and 20 lbs/ft³, and preferably having a density of about 2 lbs/ft³. Sectional thickness of the first outer layer can range between about 0.005" to 0.75", and preferably about 0.25". The second outer layer (for convention purposes the lower layer which contacts the ground) is constructed of a closed cell foamed thermoplastic polymeric material having a density of between about 0.5 and 20 lbs/ft³, and preferably having a density of about 3 lbs/ft³. Sectional thickness of the first outer layer can range between about 0.005" to 0.5", and preferably about 0.125". Best results for both the first and the second outer layers have been achieved using a closed cell, flexible, polyolefin foam. The foam consists of polyethylene and ethylene vinyl acetate (EVA) wherein the EVA content is between about nominal to 20% by weight.

As with selection of the material for use as the inner or core layer, selection of material for the outer layers is not limited to varieties of closed cell foam used with a preferred embodiment. Those persons skilled in the art will realize the broad scope of materials having the requisite level of stiffness, resilience, compressibility, and insulative characteristics. While use of closed cell foam material for the second or bottom layer is preferred, it is within the scope of the invention to use sheet material such as solid polyethylene to form either or both of the top and bottom iayers.

Bonding between the inner layer and the two outer layers can be achieved by any traditional means for bonding the resilient materials selected to construct the invention. Thus, direct thermal bonding, flame laminating, or chemical adhering are within the scope of possibilities for bonding the layers. When using the layers described above with respect to a preferred embodiment, it has been ascertained that latex based adhesive PO9050 manufactured by Bostik, Inc., or Fastbond 100 neoprene-based adhesive by 3M provide a suitable bond between the several layers when used according to the manufacturers recommendations. The bonding process referenced above is preferably enhanced by using thermoforming. In such a process, the laminate set up is subjected to heat and compression to ensure that the bond at the layer interfaces is complete and coextensive. It is during this process, that any features or surface details can be formed on the first and/or second outer layers. In addition, if a perimeter bond is desirable, the same can be accomplished at this stage. Thus, while basic adhesion between the several layers is carried out prior to thermoforming the pad, the thermoforming process not only enhances the bond, but can also be used to establish any perimeter bond and outer surface details.

These and other features of the invention will be better ascertained by reference to the accompanying drawings and to the detailed description of the invention which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of the invention shown in a rolled or stowed state;

Fig. 2 is an end elevation view of the invention shown in Fig. 1 ;

Fig. 3 is a perspective view of the invention shown in an unrolled or ready to use state; Fig. 4 is a perspective detail of a portion of the invention shown in Fig. 3;

Fig. 5 is a cross section elevation taken substantially along the line 5 - 5 in Fig. 4 detailing the contours of the various foam materials used to construct the invention;

Fig. 5a is a perspective view in partial cross section of an alternative embodiment wherein the upper surface contours or features are transverse ribs;

Fig. 6 is a partial perspective view of the lower side of the invention;

Fig. 7 is a partial perspective view of the upper side of the invention wherein the several foam laminates are partially peeled away;

Fig. 8 is a plot of pad deflection versus a10 inch² surface load comparing a non-contoured pad and a pad having features molded in the upper surface thereof; and

Fig. 9 is a plot of maximum fill height versus contour diameter (dimensionless) illustrating certain permissible ratios between these two values when creating contours that must be filled by a foam core during manufacture and having a schematic inset showing the testing apparatus.

DETAILED DESCRIPTION OF THE INVENTION Turning then to the several figures wherein like numerals indicate like parts, and more particularly to Figs. 1- 5, the general nature of pad 10 is shown. Pad 10 comprises upper shell portion 20, lower shell portion 30, and core 40, alternatively referred to as first layer 20, second layer 30, and third layer 40. Upper shell portion 20 has outer surface 22, inner surface 24, and perimeter portion 26; similarly lower shell portion 30 has outer surface 32, inner surface 34, and perimeter portion 36. Core 40 has first major surface 42 and second major surface 44 in addition to peripheral surface 46. Both shell inner surfaces 24 and 34 are wholly bonded to, respectively, major surfaces 42 and 44 of core 40. Upper shell portion 20 is bonded at its perimeter portion 26 to perimeter portion 36 of lower shell, thereby encasing core 40 and defining an enclosed volume . It should be noted, however, that a perimeter portion of core 40 may be disposed between inner surfaces 24 and 34 only to the extent that such interposition does not negatively affect the bonding of the two portions. The straps 50a and 50b and their attachment mechanism 60 are removable and optional.

Upper shell portion 20 is preferably formed from a 24" wide and 72" long slab of closed cell polyethylene and ethylene vinyl acetate foam material having a maximum EVA content from about nominal to 10%. Those persons skilled in the art will appreciate the effect that the addition of EVA will provide, namely enhanced flexibility. Thus, while durability of upper shell portion 20 is desirable, the overall comfort of this layer should not be sacrificed in favor of durability as compared to lower shell portion 30 described in detail below. Final sectional thickness is preferably about 0.25" based upon the overall dimensions of pad 10 described herein, although the acceptable range is from about 0.005" to 0.5". Upper shell portion 20 preferably has a density of about 2 lbs/ft³, although the range can be from 0.5 to about 20 lbs/ft³. A beneficial feature of upper shell portion 20 is that the chosen material is inherently hydrophobic. Consequently, water and water based solvents are not drawn towards shell portion 20. Thus, core 40 tends to remain dry as will be described in more detail below.

Lower shell portion 30 is also preferably formed from a 24" wide and 72" long slab of closed cell polyethylene and ethylene vinyl acetate foam having a maximum EVA content of about from nominal to 2% depending upon the degree of toughness desired. Sectional thickness is preferably about 0.125" based upon the overall dimensions of pad 10 described herein, although the acceptable range is from about 0.005" to 0.5". Upper shell portion 20 preferably has a density of about 3 lbs/ft³, although the range can be from 0.5 to about 20 lbs/ft³. As with upper shell portion 20, the selected material is inherently hydrophobic. The densities for both lower and upper sections are defined by The American Society for Testing Materials (ASTM) in method D-3575.

Finally, core 40 is preferably formed from a 24" wide and 72" long slab of open cell polyurethane foam having a sectional thickness of about 1.25" based upon the overall dimensions of pad 10 described herein, although the acceptable range is from about 0.25" to 4". Core 40 preferably has a density of about 1.45 lbs/ft³ and a stiffness 25%IFD value of 36 lbs., although the density range can be from 0.5 to about 20 lbs/ft³ and the 25% IFD stiffness value range can be from 10 to 45 lbs. The values of density and IFD are defined by the American Society for Testing and Materials (ASTM) in Method 3574. While not necessary to the operation of the invention, the width and length dimensions of core 40 are slightly less than the overall pad dimensions since it is wholly surrounded by upper shell portion 20 and lower shell portion 30. In this manner, when perimeter portions 26 and 36 are joined as described below, no portion of core 40 is exposed directly to the environment. Consequently, the hydrophilic nature of core 40 will not degrade from the performance of pad 10 by contact leaching of moisture from the environment.

Those persons skilled in the art will appreciate the stiffness to density ratio present in the instant invention: core 40 has a relatively high stiffness for the given density. In conventional self-inflating pads, a high stiffness value would otherwise provide less comfort to a user. However, because upper shell portion 20 is constructed from a foam having a relatively high density, localized compression loading of this surface is distributed across a greater area of core 40 than would be possible using a flexible fabric shell. Thus, a greater self-inflation biased foam can be used, which also provides for enhanced support features without sacrificing user comfort. By the same token, a very low density core can be used without sacrificing performance of pad 10. Because the instant invention is vented to atmosphere, a higher IFD foam is used to provide adequate support to prevent the user from "bottoming out" onto the ground.

While it is considered desirable to use an upper shell portion having a higher density than the core, it may be desirable to modify the compliance of the upper shell without modifying the composition of the material comprising the upper shell. Through research, it has been found that the deflection or compliance characteristics of a given upper shell portion material can be varied by forming certain details therein. As best shown in Fig. 8, greater deflection or compliance of pad 10 can be achieved when certain modifications in the form of features are formed in upper shell portion 20 as compared to a similar pad not having features formed therein. It is also beneficial to note the relatively smooth deflection curve produced by pad 10 when incorporating upper shell features. As those persons skilled in the art will appreciate, conventional self-inflating pads have a desirable compliance curve until the portion of the core subject to loading is fully compressed, where after the compliance values sharply level off. By utilizing a moderately compliant upper shell portion, a highly compliant core, and low compliance lower shell portion, it is possible to provide desirable progressive compliance characteristics to pad 10.

Turning to Figs. 3 and 4, it can be seen that the contours or details noted above preferably take the form of a series of convex dome protrusions 12 that are formed in upper shell portion 20. To ascertain the nature of desirable contours to incorporate in pad 10 so as to vary the initial compliance, two primary factors were considered. The first factor related to the effect that contour incorporation would have on the nature of the bond interface between major surface 42 of core 40 and inner surface 24 of upper shell portion 20; the bond should be coextensive and robust. The second factor related to user perception of comfort. Incidental considerations included whether the contours would enhance or degrade use or storage of a pad, deleteriously affect the insulation properties of a pad, and withstand being rolled and compressed for long periods without being permanently deformed.

Regarding the first factor and as a preliminary matter, contours or details having sharp edges or deep profiles would likely decrease the ability of inner surface 24 of upper shell portion 20 to bond with major surface 42 of core 40. Thus, the nature of any given detail should not include radical areas of surface transition or nook and crannies that would be difficult for the core material to occupy.

To determine viable detail parameters during the development of the invention, the inventors formed holes of various diameters in a compression die and subjected core 40, consisting of a 36 lb. 25% IFD, 1.45 Ib./ft³ density slab of polyurethane foam, to various compression loads. The results of these tests, shown in Fig. 9, assisted the inventors in determining the permissible physical parameters for any potential detail: because the core material would only extend to a limited degree during manufacturing compression based upon a given hole dimension, the selected detail would have to have a volume equal to or less than the observed core volume extending beyond the compression die, and have complimentary physical parameters. Thus, selection of a detail that would retain sufficient contact with the core material would ensure that there would be sufficient bonding between the core and the upper shell portion.

Concerning the second factor, earlier research derived during development of a conventional closed cell pad such as is described in United States Patent number 4,980,936 incorporated by reference herein indicated that a protrusion 12 having a diameter of about 2" (based upon the overall dimensions of the pad described herein) provided the desired level of deflection modification (increasing compliance) while remaining essentially undetectable by the user. Naturally, the nature of material used and pad deflection properties will be variables worthy of consideration. Therefore, the foregoing is intended to provide an example of second factor considerations and not a limitation thereof, as will be shown with respect to a second embodiment in Fig. 5a.

As a consequence of these two initial findings, in combination with the ancillary considerations noted above, it was found that domed convex protrusions having a diameter of about 2" were optimal. The location and arrangement of protrusions 12 on outer surface 22 were selected based in part upon the knowledge that pad 10 would be subject to rolling for storage purposes. Thus, protrusions 12 are aligned in rows wherein outer surface 22 of upper shell portion 20 has transverse unadultered portions 14 (see Fig. 4) so that pad 10 will accept transverse creases when rolled for storage. Moreover, every other row of protrusions 12 are longitudinally aligned, with every row being laterally offset from the adjacent rows by a factor of about ∑ protrusion. This offset prevents longitudinally adjacent protrusions 12 from directly interfering with each other when pad 10 is rolled for storage purposes. These two factors are demonstrated with reference to Figs. 1 and 2.

An alternative embodiment to that shown in Figs. 1-5 is shown in Fig. 5a. Here, a series of transverse lands 14a are formed in outer surface 22 of upper shell portion 20. Protrusions 12a take the form of ribs as opposed to the domed convex protrusions 12 shown in Figs. 4 and 5. Similar parameters are used to evaluate the physical dimensions of protrusions 12a as were considered with respect to protrusions 12.

Heretofore, attention has been given primarily to upper shell portion 20. However, lower shell portion 30 also has contours formed therein. Turning to Fig. 6, it can be seen that a plurality of transverse lands 16 are formed in lower shell portion 30. These lands correspond sectionally with transverse unadulterd portions 14 in upper shell portion 20 as best shown in Fig. 5, thereby creating transverse portions of pad 10 that naturally accept a folding bias. Consequently, by segmenting pad 10 in such a manner, it more readily rolls for storage as demonstrated in Fig. 2, and more readily accepts a planar shape after initial inflation. In addition, these lands impart transverse beam strength to the pad, which mitigates against pad distortion during rolling. Beam rigidity during rolling aids in the compression of inner core 40 resulting in a smaller stowed volume.

In the preferred embodiment, a higher density closed cell foam is chosen for the lower shell 30. A higher density foam generally will have superior tensile, tear and abrasion resistance as will be needed on a shell contacting the ground.

Also formed in lower shell portion 30 are a pair of longitudinal lands 18a and 18b (only 18a being shown in Fig. 6). These features are intended to provide a convenient means for locating compression straps 50a and 50b (see Figs. 1 and 3). By providing for strap location in the manner shown, the higher density material present at lands 18a and 18b will increase durability of pad 10 in these areas that will be subject to repeated abrasion from strap use and high compression loads. While lands 18a and 18b need not extend the entire length of pad 10, for convenience they do so.

As noted previously, the present invention may provide for active or passive inflation and deflation. Active inflation and deflation is defined as involving user intervention, usually by way of operation of a valve that is in fluid communication with the interior chamber defined by upper shell portion 20 and lower shell portion 30. Passive inflation and deflation is defined as not involving user intervention, except for compressing and expanding the volume of pad 10 such as when stowing or using the same. Because the material selected in a preferred embodiment for upper and lower shell portions 20 and 30 is to a reasonable extent, inherently fluid impervious, the chamber defined thereby is capable of maintaining a constant volume of fluid or air. Because core 40 is wholly bonded at its major surfaces 42 and 44 to the outer shells, core 40 is caused to act as a tension member. Thus, by incorporating a valve in the manner disclosed and taught by the patents for self-inflating pads referenced herein, the benefits of such a construction can be realized.

However, in view of the short-comings associated with such structures as recited above, pad 10 can also be, and is preferably, used in the passive mode. Referring specifically to Figs. 4 and 5, it can be seen that a plurality of slits 28 are formed in outer surface 22 of upper shell portion 20. It is desirable to place slits 20 at the top of protrusions 12 so that water is less likely to accumulate over them. These slits have a normal closure bias as a function of material selection so that only when an above nominal pressure differential exists between the environment and the chamber will pad 10 passively inflate or deflate. Furthermore, because upper shell portion 20 is constructed from inherently hydrophobic material, contact moisture migration is all but eliminated, thus preserving the integrity of core 40, which is noticeably hydrophilic.

It is highly desirable to eliminate moisture from the core 40 because it gives the undesirable effects of: increasing the weight which must be carried, greatly reduces the insulating properties of the core, and leads to degradation of the physical properties of the core 40 and adhesives used to bond the shells to the core.

Claims

What is claimed:

1. An [SME2]inflatable body comprising: a first outer layer constructed from a first type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; a second outer layer constructed from a second type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; and an inner layer constructed from a third type of resilient material which defines a first major surface, a second major surface, and a perimeter portion wherein the inner layer is disposed between and securely bonded at least in part to the inner surface of the first outer layer and the inner surface of the second outer layer.

2. The inflatable body of claim 1 wherein the first type of resilient material is substantially the same as the second type of resilient material.

3. The inflatable body of claim 1 wherein the first type of resilient material is selected from the group consisting of polyolefins, neoprenes, polyvinyl chloride, EVA, nitrile rubbers, laytex, and polyurethanes.

4. The inflatable body of claim 1 wherein the second type of resilient material is selected from the group consisting of polyolefins, neoprenes, polyvinyl chloride,

EVA, nitrile rubbers, laytex, and polyurethanes.

5. The inflatable body of claim 1 wherein the third type of resilient material is selected from the group consisting of polymeric foams, polyurethane foams, fiber battings and polyolefin foams.

6. The inflatable body of claim 1 wherein the first major surface of the inner layer is wholly bonded to the inner surface of the first outer layer and the second major surface of the inner layer is wholly bonded to the inner surface of the second outer layer.

7. The inflatable body of claim 1 wherein the first outer layer has a density less than the second outer layer.

8. The inflatable body of claim 1 wherein the first and second outer layers are substantially directly bonded to each other at common peripheral portions.

9. The inflatable body of claim 1 wherein the outer surface of the first outer layer has contours formed therein.

10. The inflatable body of claim 1 wherein the outer surface of the second outer layer has contours formed therein.

11. The inflatable body of claim 1 wherein the first outer layer is formed from a slab of closed cell foam, the second outer layer is formed from a slab of closed cell foam, and the inner layer is formed from a slab of open cell foam, and wherein the first and second outer layers are substantially bonded to each other at their common peripheral portions thereby defining a chamber.

12. The inflatable body of claim 1 wherein at least one outer layer defines at least one orifice to permit the ingress and egress of fluid into and out of the chamber.

13. The inflatable body of claim 12 wherein a plurality of convex dome contours are formed in the outer surface of the first outer layer.

14. The inflatable body of claim 13 wherein a plurality of transverse land contours are formed in the outer surface of the second outer layer.

15. The inflatable body of claim 12 wherein a plurality of transverse lands are formed in the outer surface of the second outer layer.

16. The inflatable body of claim 11 wherein the surface area of the inner layer's first major surface is less than the surface area of the first outer layer's inner surface.

17. An [SME3]inflatable body comprising: a first fluid impervious outer layer constructed from a first type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; a second fluid impervious outer layer constructed from a second type of resilient material which defines an outer surface, an inner surface, and a perimeter portion; an inner layer constructed from a third type of resilient material which defines a first major surface, a second major surface, and a perimeter portion wherein the inner layer is disposed between and securely bonded at least in part to the inner surface of the first outer layer and the inner surface of the second outer layer and wherein the first and second outer layers are bonded to each other at their common peripheral portions thereby defining a fluid impervious chamber; and a valve for permitting ingress and egress of fluid into the chamber.

18. The inflatable body of claim 17 wherein the first type of resilient material is substantially the same as the second type of resilient material.

19. The inflatable body of claim 17 wherein the first type of resilient material is selected from the group consisting of polyolefins, neoprenes, polyvinyl chloride, EVA, nitrile rubbers, laytex, and polyurethane.

20. The inflatable body of claim 17 wherein the second type of resilient material is selected from the group consisting of polyolefins, neoprenes, polyvinyl chloride, EVA, nitrile rubbers, laytex, and polyurethane.

21. The inflatable body of claim 17 wherein the third type of resilient material is selected from the group consisting of polymeric foams, polyurethane foams, fiber battings and polyolefin foams.

22. The inflatable body of claim 17 wherein the first major surface of the inner layer is wholly bonded to the inner surface of the first outer layer and the second major surface of the inner layer is wholly bonded to the inner surface of the second outer layer.

23. The inflatable body of claim 17 wherein the first outer layer has a density less than the second outer layer.

24. The inflatable body of claim 17 wherein the outer surface of the first outer layer has contours formed therein.

25. The inflatable body of claim 17 wherein the outer surface of the second outer layer has contours formed therein.

26. The inflatable body of claim 17 wherein the first outer layer is formed from a slab of closed cell foam, the second outer layer is formed from a slab of closed cell foam, and the inner layer is formed from a slab of open cell foam.

27. The inflatable body of claim 26 wherein the first outer layer has a plurality of convex dome contours formed thereon and the second outer layer has a plurality of transverse lands formed thereon.

28. An [SME4]inflatable body comprising: a first outer layer constructed from a closed cell foam material having a first density, and which defines an outer surface, an inner surface, and a perimeter portion; a second outer layer constructed from a closed cell foam material having a second density that is greater than the first density, and which defines an outer surface, an inner surface, and a perimeter portion; and an inner layer constructed from an open cell foam material which defines a first major surface, a second major surface, and a perimeter portion wherein the inner layer is wholly enveloped by and securely bonded at least in part to the inner surface of the first outer layer and the inner surface of the second outer layer and wherein the first outer layer defines a plurality of passages to permit gas ingress and egress to and from the inner layer.

29. The inflatable body of claim 28 wherein the first outer layer has a plurality of surface contours.