U.S. patent application number 12/683547 was filed with the patent office on 2010-07-08 for memory foam mattress and method of construction.
Invention is credited to William H. Rose.
Application Number | 20100170042 12/683547 |
Document ID | / |
Family ID | 42310732 |
Filed Date | 2010-07-08 |
United States Patent
Application |
20100170042 |
Kind Code |
A1 |
Rose; William H. |
July 8, 2010 |
Memory Foam Mattress and Method of Construction
Abstract
The present invention is directed toward an improved foam
mattress. In one embodiment, the mattress has a base layer coupled
to rectangular side sections each having a top surface. The top
surfaces of the side sections extend above the top surface of the
base layer and define a periphery of a space. The base layer and
side sections are made of a material having a first resiliency. A
central core layer is configured to fit entirely within the space
defined by the side sections and is made of a material having a
second resiliency, where the second resiliency is lower than said
first resiliency. A top layer rests on the top surface of the
central core layer and the top surface of the side sections. The
top layer is made of a material of having a resiliency equal to or
less than the second resiliency.
Inventors: |
Rose; William H.;
(Rockledge, FL) |
Correspondence
Address: |
PATENTMETRIX
14252 CULVER DR. BOX 914
IRVINE
CA
92604
US
|
Family ID: |
42310732 |
Appl. No.: |
12/683547 |
Filed: |
January 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61143365 |
Jan 8, 2009 |
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Current U.S.
Class: |
5/698 ;
5/739 |
Current CPC
Class: |
A47C 27/15 20130101;
A47C 27/148 20130101 |
Class at
Publication: |
5/698 ;
5/739 |
International
Class: |
A47C 27/15 20060101
A47C027/15 |
Claims
1. A mattress comprising: a base layer, having a top surface,
coupled to a plurality of rectangular side sections each having a
top surface, wherein the top surfaces of said side sections extend
above the top surface of the base layer and define a periphery of a
space and wherein said base layer and side sections are made of a
material having a first resiliency; a central core layer, having a
top surface, configured to fit entirely within the space defined by
the side sections, said central core layer being made of a material
having a second resiliency, wherein said second resiliency is lower
than said first resiliency; and a top layer that rests on the top
surface of the central core layer and the top surface of the side
sections, said top layer being made of a material of having a
resiliency equal to or less than the second resiliency.
2. The mattress of claim 1, wherein the side sections provide
support at the edges of the mattress.
3. The mattress of claim 1, wherein said side sections are
individual members bonded to said base layer.
4. The mattress of claim 1, wherein the side sections and said base
layer are shaped from a single contiguous unit of material.
5. The mattress of claim 1 further comprising an air foam layer
placed between the top layer and the central core layer.
6. The mattress of claim 1 further comprising an air foam layer
placed between the central core layer and the base layer.
7. The mattress of claim 1, wherein the mattress is encased with at
least one fire retardant fabric cover.
8. The mattress of claim 1, wherein the ILD for the material of the
base layer and the side sections is in the range of 20 to 40.
9. The mattress of claim 1, wherein the ILD for the material of the
central core layer and the top layer is in the range of 12 to
16.
10. The mattress of claim 1, wherein the material used for the base
layer, side sections, central core layer and the top layer is a
visco-elastic polyurethane foam.
11. The mattress of claim 1, wherein the overall thickness of the
mattress is in the range of 7 to 13 inches.
12. A mattress comprising: a base layer, having a top surface,
coupled to four rectangular side sections each having a top
surface, wherein the top surfaces of said side sections extend
above the top surface of the base layer and define a periphery of a
space and wherein said base layer and side sections are made of a
material having a first resiliency; a central core layer, having a
top surface, configured to fit entirely within the space defined by
the four side sections, said central core layer being made of a
material having a second resiliency, wherein said second resiliency
is lower than said first resiliency; and a top layer that rests on
the top surface of the central core layer and the top surface of
the side sections, said top layer being made of a material of
having a resiliency equal to or less than the second
resiliency.
13. The mattress of claim 12, wherein the thickness of each of said
four side sections is in the range of 1 to 4 inches, and wherein
the width of said side sections is in the range of 2 to 4
inches.
14. The mattress of claim 12, wherein the thickness and width of
side sections at the foot and head of the mattress is less than
that of the side sections at the sides of the mattress.
15. The mattress of claim 12, wherein said side sections are
individual members bonded to said base layer.
16. The mattress of claim 12, wherein the side sections and said
base layer are shaped from a single contiguous unit of
material.
17. The mattress of claim 12, wherein the ILD for the material of
the base layer and the side sections is in the range of 20 to
40.
18. The mattress of claim 12, wherein the ILD for the material of
the central core layer and the top layer is in the range of 12 to
16.
19. The mattress of claim 12, wherein the material used for the
base layer, side sections, central core layer and the top layer is
visco-elastic polyurethane foam.
Description
CROSS-REFERENCE
[0001] The present application relies on U.S. Patent Provisional
Application No. 61/143,365, filed on Jan. 8, 2009, and incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
mattresses, and, more specifically, to a multi-layered foam
mattress that allows for customization of the overall firmness,
thickness and breathability of the mattress along with providing a
uniform experience across the entire surface of the mattress.
BACKGROUND OF THE INVENTION
[0003] A conventional mattress generally includes a set of metal
springs or coils mounted either on a base under a pad, or
sandwiched in the center of a pair of pads. The metal springs and
pad or pads are then covered with a strapping material. The entire
structure is then sewn into a fabric cover and the edges are
wrapped and sewn. Thus, once the mattress is fabricated, the
components are not replaceable.
[0004] The limitations of metal spring mattresses combined with
improved quality and durability of foam products has lead to the
development of a foam core mattress as an alternative to metal
spring mattress. A foam core mattress provides improved comfort and
support compared with conventional spring-based mattresses. For
example, spring-based mattresses inherently have varying feel
properties over their surface, and it is quite difficult to
perceivably remove or allay the variations of these feel properties
relating to zone and surface areas.
[0005] A basic foam mattress may include one or more layers of foam
having desirable properties and that are enveloped into a fabric
cover. Typically, such a foam mattress may include a center core of
relatively high resilience foam sandwiched between two layers of
lower resilience foam encased in a fabric shell. This configuration
allows for a reversible mattress. Typically, in prior art foam
mattresses having multiple horizontal layers, the bottom layer
comprising high resiliency foam is rigid and about 5-7 inches
thick. On top of this layer are additional layers designed to
provide the sleep comfort, such as egg crate foam and a
viscoelastic layer. The viscoelastic layer provides softness to the
mattress and is typically 3-5 inches thick. One of the major
drawbacks of this design is that towards the edges of the mattress,
the viscoelastic foam does not provide enough support. As a result,
the user experiences a feeling of falling off the side of the
bed.
[0006] Some prior art mattresses try to give more support around
the edges by providing triangular wedges around the sides of the
mattress. FIG. 1 illustrates an exemplary prior art mattress which
includes 3''.times.3'' triangular wedges 101 at the sides. The
problem with this design is that there is limited surface area to
provide support on the top 103 of edges.
[0007] Since mattresses in this day are viewed highly personally,
people look forward to enhanced comfort, especially with regard to
firmness of the mattress. Consumers also demand better flexibility
and the ability to customize the overall firmness, thickness and
even feel of their mattress. Besides expecting enhanced durability
of their mattress, people also look forward to breathability,
specifically to the perceived temperature, which in case of
luxury/costly layered-foam mattresses is highly desirable.
[0008] Accordingly, there is need in the prior art for an improved
mattress that allows for better maneuverability of desired
functional features of the mattress such as firmness, thickness,
durability, provides uniform experience across the surface of the
mattress, and provides for improved support at the mattress
edges.
SUMMARY OF THE INVENTION
[0009] One embodiment of the present invention is directed toward a
mattress comprising a base layer, having a top surface, coupled to
a plurality of rectangular side sections each having a top surface,
wherein the top surfaces of said side sections extend above the top
surface of the base layer and define a periphery of a space and
wherein said base layer and side sections are made of a material
having a first resiliency; a central core layer, having a top
surface, configured to fit entirely within the space defined by the
side sections, said central core layer being made of a material
having a second resiliency, wherein said second resiliency is lower
than said first resiliency; and a top layer that rests on the top
surface of the central core layer and the top surface of the side
sections, said top layer being made of a material of having a
resiliency equal to or less than the second resiliency.
[0010] The side sections provide support at the edges of the
mattress. Optionally, the side sections are individual members
bonded to said base layer. The side sections and said base layer
are shaped from a single contiguous unit of material. The mattress
further comprises an air foam layer placed between the top layer
and the central core layer. The mattress further comprises an air
foam layer placed between the central core layer and the base
layer. The mattress is encased within at least one fire retardant
fabric cover. The ILD for the material of the base layer and the
side sections is in the range of 20 to 40, such as 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40.
The ILD for the material of the central core layer and the top
layer is in the range of 12 to 16, such as 12, 13, 14, 15, or 16.
The material used for the base layer, side sections, central core
layer and the top layer is a visco-elastic polyurethane foam. The
overall thickness of the mattress is in the range of 7 to 13
inches.
[0011] In another embodiment, the mattress comprises a base layer,
having a top surface, coupled to four rectangular side sections
each having a top surface, wherein the top surfaces of said side
sections extend above the top surface of the base layer and define
a periphery of a space and wherein said base layer and side
sections are made of a material having a first resiliency; a
central core layer, having a top surface, configured to fit
entirely within the space defined by the four side sections, said
central core layer being made of a material having a second
resiliency, wherein said second resiliency is lower than said first
resiliency; and a top layer that rests on the top surface of the
central core layer and the top surface of the side sections, said
top layer being made of a material of having a resiliency equal to
or less than the second resiliency. The thickness of each of said
four side sections is in the range of 1 to 4 inches, and wherein
the width of said side sections is in the range of 2 to 4 inches.
The thickness and width of side sections at the foot and head of
the mattress is less than that of the side sections at the sides of
the mattress. The side sections are individual members bonded to
said base layer. The side sections and said base layer are shaped
from a single contiguous unit of material. The ILD for the material
of the base layer and the side sections is in the range of 20 to
40. The ILD for the material of the central core layer and the top
layer is in the range of 12 to 16. The material used for the base
layer, side sections, central core layer and the top layer is
visco-elastic polyurethane foam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features and advantages of the present
invention will be appreciated, as they become better understood by
reference to the following Detailed Description when considered in
connection with the accompanying drawings, wherein:
[0013] FIG. 1 illustrates an exemplary prior art mattress which
includes triangular wedges at the sides;
[0014] FIG. 2a is an illustration of a composite mattress
structure, according to one embodiment of the present
invention;
[0015] FIG. 2b is an expanded view illustration of the composite
mattress structure shown in FIG. 2a;
[0016] FIG. 3a shows a representative embodiment of the mattress
structure shown in FIG. 2a;
[0017] FIG. 3b show a representative embodiment of the mattress
structure shown in FIG. 2b;
[0018] FIG. 4 illustrates another embodiment of the mattress
structure;
[0019] FIG. 5 is a depiction of another embodiment of the composite
mattress structure of the present invention;
[0020] FIG. 6a is an illustration of one embodiment of the
composite mattress structure;
[0021] FIG. 6b is an illustration of another embodiment of the
composite mattress structure; and
[0022] FIG. 6c is an illustration of yet another embodiment of the
composite mattress structure; and
[0023] FIG. 7 illustrates another embodiment of the composite
mattress of the present invention with supportive edges on all the
four sides.
DETAILED DESCRIPTION OF THE INVENTION
[0024] In one embodiment, the present invention is directed towards
a composite mattress that allows for customization of its overall
thickness and firmness.
[0025] In another embodiment, the present invention is directed
towards a mattress having a uniform comfort level across the entire
surface for allowing an individual to sit or sleep even at the
edges without causing the mattress to deform or bend. The design of
the mattress of present invention also prevents people from feeling
as if they're going to fall off when sleeping on the edge of the
bed.
[0026] In one embodiment, the present invention is directed towards
a mattress comprising a base foam layer that further comprises a
central base foam layer and two raised side sections, forming a
T-shape structure; a central core foam layer that fits tightly
within the channel created by the side sections over the base foam;
and a topper foam layer that fully covers the top surfaces of the
side sections and the central core foam.
[0027] In one embodiment of the mattress of the present invention,
the density of the base foam layer is greater than the density of
the core foam layer and topper foam layer. In addition, the
densities of the core foam layer and topper foam layer can be
varied and/or interchanged to customize the overall firmness of the
mattress.
[0028] In one embodiment of the present invention, the base foam
layer is firm and provides sturdy support to the topper layer, even
along the edges, for a uniform feel across the surface of the
mattress. The overall thickness of the mattresses is dependent on
the thicknesses of the side sections and the topper foam layer
along with any additional layer of foam that may optionally be
added over the topper foam layer.
[0029] In another embodiment, the composite mattress of the present
invention includes edge support on all the four sides.
[0030] In yet another embodiment, the present invention is directed
towards a mattress that has better air permeability thereby
allowing for better control of temperature of the mattress when an
individual is using it. Thus, in one embodiment, the mattress of
the present invention comprises a breathable air foam layer in
addition to the base foam layer, the core foam layer, and the
topper foam layer. In one embodiment the air foam layer is placed
immediately underneath the topper foam layer and above the core
foam layer, which in turn, is placed on top of the base foam layer.
In another embodiment the air foam layer is sandwiched between the
base foam layer and the core foam layer.
[0031] In another embodiment of the present invention, the mattress
is wrapped with at least one fire retardant fabric cover.
[0032] Various modifications to the preferred embodiment, disclosed
herein, will be readily apparent to those of ordinary skill in the
art and the disclosure set forth herein may be applicable to other
embodiments and applications without departing from the spirit and
scope of the present invention and the claims hereto appended.
Reference will now be made in detail to specific embodiments of the
invention. Language used in this specification should not be
interpreted as a general disavowal of any one specific embodiment
or used to limit the claims beyond the meaning of the terms used
therein.
[0033] FIGS. 2a and 2b illustrate one embodiment of the composite
mattress structure 200 in accordance with an aspect of the present
invention. Composite mattress 200 comprises base foam layer 204 and
two longitudinally extending side foam sections 203. In addition,
composite mattress further comprises a central foam core layer 210
that is received in the opening or space defined by side sections
203 and base foam layer 204; and foam topper layer 215 that rests
on the top surface of central foam core layer 210 and side foam
sections 203. In one embodiment, base foam layer 204 and raised
side sections 203 are formed into a single unit of foam that has
been shaped accordingly. In an alternate embodiment, base foam
layer 204 and side foam layers 203 are fabricated as discrete
components and assembled via bonding.
[0034] Referring now to both FIGS. 2a and 2b, the overall width 220
(X.sub.o) and length 225 (L.sub.o) of the composite mattress 200 is
determined by the corresponding dimensions of industry standard
beds that are commercially available, such as a king or queen-sized
bed. However the width 220 and length 225 of the mattress 200 can
also be customized.
[0035] In one embodiment, side sections 203 have widths of X.sub.s1
and X.sub.s2 respectively. In one embodiment X.sub.s1 is equal to
X.sub.s2, however in an alternate embodiment X.sub.s1 is not equal
to X.sub.s2. The width of base foam section 204 is determined as
X.sub.b=X.sub.0-(X.sub.s1+X.sub.s2). The width X.sub.c of foam core
210 is also equal to the width X.sub.b of base foam 204, in one
embodiment, such that core foam layer 210 fits squarely in the
channel defined by side sections 203 and base foam 204. The width
of foam topper layer 215 is equal to X.sub.o which is the overall
width of the composite mattress 200 so that the topper 215 fully
covers the side sections 203 and the core foam layer 210.
[0036] The mattress of the present invention is advantageous in
that the two side sections 203 provide support to the topper foam
layer 215 along the edges allowing an individual to sleep, sit or
rest on the edges of the mattress 200 without causing the mattress
200 to deform, bend or warp and thus giving the individual a
uniform resting experience on the entire surface of the mattress
200. According to another aspect of the present invention, the
width of the two side sections X.sub.s1, X.sub.s2 is chosen to
optimize mattress support along the edges while maximizing the
width X.sub.c of the core foam 210 that defines the primary rest
area for the individual.
[0037] Further, since the side sections for providing edge support
are rectangular, it provides more top edge support than the
triangular wedges used for edge support in prior art mattresses.
This is because rectangular side sections have more surface area to
provide better edge support.
[0038] The overall thickness 230 (T.sub.o) of the mattress 200 is
defined by the thickness T.sub.s of the side sections 203 and that
of the topper foam 215 denoted as T.sub.t. Thus,
T.sub.o=T.sub.s+T.sub.t. In an alternate embodiment, the overall
thickness T.sub.o of the mattress 200 depends on the thickness
T.sub.s of the side sections 203, the thickness of the topper foam
215, denoted as T.sub.t, and the thickness T.sub.other of any
optional foam layer(s) placed over the topper foam layer 215. Thus,
in this case T.sub.o=T.sub.s+T.sub.t+T.sub.other. Also, the
thickness T.sub.b of the base foam 204 and T.sub.c of the core 210
is such that T.sub.b T.sub.c=T.sub.s, that is, the sum of the
thickness of the base 204 and core 210 is equal to the thickness of
the side sections 203. In one embodiment T.sub.b is equal to T. In
another embodiment T.sub.b is not equal to T.sub.c where
T.sub.b>T.sub.c or T.sub.c>T.sub.b. However, in all
embodiments the core 210 does not rise above the top edges of the
side sections 203. The thickness T.sub.t of the topper foam 215 may
or may not be equal to those of the base 204 or the core 210.
[0039] In one embodiment, the various components of the composite
mattress 200 are made of visco-elastic polyurethane foam, also
referred to as memory foam or foam rubber. Viscoelastic foam is
typified by its slow recovery after compression. Due to this
property, viscoelastic foam can closely conform to the shape of the
human body, and can efficiently distribute pressure over the whole
surface. Viscoelastic foam also has ability to dampen vibration as
well as absorb shock, absorbing up to 90% of impact. In addition to
these key advantages, viscoelastic foam also reacts to body
temperature and ambient temperatures, softening with heat and
adjusting more easily to body contours. Due to its conforming
aspect, viscoelastic material makes for a comfortable yet
supportive mattress or mattress pad, and its low resilience works
especially well in medical applications, for people with impaired
mobility.
[0040] One of ordinary skill in the art would however appreciate
that any material providing support and firmness characteristics
similar to those provided by foam rubber can be used in the
mattress of the present invention without exceeding the scope of
the invention. Examples of alternate materials comprise latex foam,
coir foam, XPS (Extruded Polystyrene) foam such as Styrofoam or
Foamcore, or any other similar material known to persons of
ordinary skill in the art.
[0041] In one embodiment of the mattress of the present invention,
the thicknesses and densities of the side foam sections 203, base
foam layer 204, core foam layer 210, topper foam layer 215 and
therefore that of the overall composite mattress 200 are a function
of at least the overall desired density of the composite mattress,
desired therapeutic function of the mattress, age and weight of the
individual who will be using the mattress and/or the climatic
condition and therefore the place/region where the mattress will be
used, and overall user preference.
[0042] Thus, in one embodiment the base foam structure 205
comprising of two longitudinally extending side foam sections 203
and the central base foam 204 is made of more dense and/or
resilient (and firmer) foam material while the core foam layer 210
and the topper foam layer 215 are made of comparatively less dense
and/or resilient (and thus softer) foam material. In addition, the
core foam layer 210 is, in one embodiment, firmer and/or more
resilient in comparison to the topper foam layer 215. This density
and/or resiliency variation across sections of the composite
mattress 200 is advantageous in that the softer upper layer(s),
such as the topper foam layer 215, provides gentle support to the
entire body while the firmer and/or more resilient core layer 210
provides greater support to a heavier area of the body that sinks
deeper into the mattress 200. At the same time the substantially
firmer and/or more resilient side sections 203 provide sturdy
support to the core foam layer 210 and the topper foam layer 215.
In an alternate embodiment while the core 210 and topper 215 have
lesser densities and/or resiliency, in comparison to the base foam
layer 204 and side sections 203, the densities and/or resiliencies
of the core foam layer 210 and topper foam layer 215 may be same.
In a yet another embodiment, the density and/or resiliency of the
topper foam layer 215 is substantially higher than the core foam
layer 210, which may be needed for therapeutic conditions of
spondylitis or other similar conditions of the vertebrae for which
a relatively harder/firmer bed is recommended.
[0043] One of the advantages of memory foam or visco-elastic
polyurethane foam is that depending on its overall density and
chemical additives it is firmer in cool temperatures and softer
when warm. Higher density memory foam reacts to body heat which
allows it to mould itself to the shape of a warm body within a
short time period. Thus, the density of the mattress 200 and/or
that of the topper foam layer 215 can be chosen depending upon the
climatic condition and therefore the region of use of the mattress.
In one embodiment, the density and/or resiliency of the topper foam
layer 215 that is used in cold climatic conditions is slightly
lower than that which is used in hot climatic conditions--though
the topper foam layer 215 in either case may be of high or low
density in absolute terms when viewed from industry standards or
from therapeutic functionality. The reason for this relative
density and/or resiliency difference, owing to climatic conditions,
is that in cold climates memory foam is firmer with an anticipation
that the body temperature of the user/individual would cause the
foam to soften. However, in cold climates the body temperature of
the user is likely to cause this softness of the foam over a longer
period of time owing to the effect of external temperature. Thus,
it will take a longer time for the foam to soften and provide the
anticipated comfort to the user. On the other hand, in hot climates
memory foam is softer and its interaction with body temperature of
the user may further soften the foam to an undesirable effective
density. Therefore, the topper foam layer 215 is of slightly high
density when used in hot climatic conditions.
[0044] It may be noted that the weight and the visco-elasticity of
the foam are determined by the amount of chemicals used in the
composition of the polyurethane foam. Generally the higher the
density, the greater the visco-elastic properties exhibited by the
foam. The density does not determine the firmness of the foam. The
industry standard that determines firmness of a visco elastic foam
is known as Indentation Load Deflection (ILD). ILD rating is the
number of pounds or weight required to achieve a 25% compression on
a foam using a 50 square inch indentation. For example, foam with
ILD rating 14 implies that it requires 14 lbs to acquire a 25%
compression. ILD rating indicates how hard or soft the foam is--the
higher the ILD rating, the harder the foam. ILD also determines how
easily a foam will shape to the user's body and how much support it
is capable of giving. Very low ILD foams are wonderfully cushy on
the body, but provide very little support.
[0045] FIGS. 3a and 3b show one embodiment of the mattress of FIGS.
3a, 3b, denoted as 300, whereby the width of each side section 303
(X.sub.s1 and X.sub.s2) is 2 inches. Also, in one embodiment, the
thickness T.sub.b of the base foam 304 is 4 inches, the thickness
T.sub.c of the core foam layer 310 is 2 inches and the thickness
T.sub.t of the topper foam layer 315 is 1 inch. Thus, the overall
thickness T.sub.o of mattress 300 is 7 inches. The base foam
structure of mattress 300, formed from side foam sections 303 and
base foam layer 304, is, in one embodiment, comprised of high
density polyurethane foam. To provide adequate firmness and
support, the ILD for the side foam sections 303 and base foam layer
304 is kept in the range of 20 to 40. In one embodiment, the high
density polyurethane foam is of the order of 32 ILD. In one
embodiment, the core foam layer and topper foam layer are of a
comparatively lower density; for example, such layers may be
comprised of 3.5 lb, pure visco foam, which provides adequate
visco-elasticity without being uncomfortable to the sleeper. For
the same purpose, ILD for the core and topper foam layers is kept
in the range of 12 to 16. In an additional embodiment, the density
rating of the visco foam is in the range of 2 lb to 6 lb. One of
ordinary skill in the art would appreciate that firmness and
support can be customized according to the user's preference, and
materials of suitable density and ILD rating may be used
accordingly.
[0046] In an alternate embodiment, as shown in FIG. 4, the overall
thickness T.sub.o of mattress 400 is 8 inches such that the
thickness T.sub.b of the base foam 404 is 5 inches, thickness
T.sub.c of the core foam layer 410 is 2 inches and thickness
T.sub.t of the topper foam layer 415 is 1 inch. Persons of ordinary
skill in the art should note that the densities and thicknesses
above are exemplary only and in no way are meant to be limiting to
the invention.
[0047] FIG. 5 shows an embodiment of composite mattress structure
500 in accordance with another aspect of the present invention.
Composite mattress 500 comprises base foam structure 505 formed
from two longitudinally extending side foam sections 503 and a
central base foam 504 deposited therebetween; foam core layer 510
that is received in the opening defined by side sections 503 and
base foam 504; air barrier foam layer 514 that rests on the top
surface of foam core layer 510, and foam topper layer 515 that
rests on the top surface of air barrier foam layer 514 and side
sections 503. While in one embodiment the base foam structure 505
is a single unit of foam that has been shaped to have the base 504
and two raised side sections 503; in an alternate embodiment the
base foam structure 505 is fabricated by bonding together discrete
pieces of base foam 504 and side foams 503.
[0048] The optional breathable air foam layer 514 allows for easier
passage of air in and out of the mattress 500. This further allows
the mattress 500 to better conform to a person's body and improves
the deformation and recovery time of the foam as the person lies
down, sits and/or moves on the mattress.
[0049] The overall width X.sub.o and length (not depicted in FIG.
5) of the composite mattress 500 is determined by the corresponding
dimensions of industry standard beds that are commercially
available, such as a king or queen-sized bed. However the width and
length of the mattress 500 can also be customized. The side
sections 503 have widths of X.sub.s1 and X.sub.s2 respectively. In
one embodiment X.sub.s1 is equal to X.sub.s2, however in an
alternate embodiment X.sub.s1 is not equal to X.sub.s2. The width
of base foam layer 504 is determined as
X.sub.b=X.sub.0-(X.sub.s1+X.sub.s2). The widths X.sub.c of foam
core layer 510 and X.sub.a of air barrier foam layer 514 are also
equal to the width X.sub.b of base foam layer 504 so that core foam
layer 510 and air barrier foam layer 514 fit tightly in the channel
defined by side sections 503 and base foam 504. The width of foam
topper layer 515 is equal to X.sub.0 which is the overall width of
the composite mattress 500 so that the topper 515 fully covers the
side sections 503, the core 510 and the air barrier foam 514.
[0050] The two side sections 503 provide support to the topper foam
layer 515 along the edges allowing an individual to sleep, sit or
rest on the edges of the mattress 500 without causing the mattress
500 to deform, bend or warp thereby giving the individual a uniform
resting experience on the entire surface of mattress 500. In one
embodiment the width of the two side sections X.sub.s1, X.sub.s2 is
chosen to optimize mattress support along the edges while
maximizing the widths X.sub.c and X.sub.a of the core foam layer
110 and air barrier foam layer 514, respectively, that define the
primary rest area for the individual.
[0051] In one embodiment, the overall thickness T.sub.o of the
mattress 500 depends on the thickness T.sub.s of the side sections
503 and that of the topper foam layer 515 denoted as T.sub.t. Thus,
T.sub.o=T.sub.s+T.sub.t. Also, the thickness T.sub.b of the base
foam layer 504, T.sub.c of the core foam layer 110 and T.sub.a of
air barrier foam layer 514 is such that
T.sub.b+T.sub.c+T.sub.a=T.sub.s, that is, the sum of the thickness
of the base 504, core foam layer 110 and air barrier foam layer 514
is equal to the thickness of the side sections 503. In one
embodiment T.sub.b is equal to T.sub.c. In another embodiment
T.sub.b is not equal to T.sub.c where T.sub.b>T.sub.c or
T.sub.c>T.sub.b. In one embodiment the thickness T.sub.a of air
barrier foam layer 514 is substantially less than the thicknesses
T.sub.b or T.sub.c of the base and core foam layers. In another
embodiment, the thickness T.sub.a is equal to either T.sub.b or
T.sub.c. In yet another embodiment, the thickness T.sub.a is
greater than T.sub.b or T.sub.c. However, in all embodiments the
air barrier foam layer 514 does not rise above the top edges of the
side sections 503. The thickness T.sub.t of the topper foam layer
515 may or may not be equal to those of the base 504, the core foam
layer 510 or the air barrier foam layer 514.
[0052] In one embodiment, the air barrier foam layer 514 is made of
poly foam that acts as a breathable air layer while other
components of the composite mattress 500 are made of visco-elastic
polyurethane foam, also referred to as memory foam or foam rubber.
However, any material providing support and firmness
characteristics similar to those provided by foam rubber can be
used without exceeding the scope of the invention. Examples of
alternate materials comprise latex foam, coir foam, XPS (Extruded
Polystyrene) foam such as Styrofoam or Foamcore, or any other
similar material known to persons of ordinary skill in the art.
[0053] FIG. 6a shows one embodiment of the mattress 500 of FIG. 5,
denoted herein as 600. As shown in FIG. 6a the width of each of the
side sections 603 X.sub.s1 and X.sub.s2 is 3 inches. Also, in this
particular embodiment, the thickness T.sub.b of the base foam layer
604 is 6 inches, the thickness T.sub.c of the core foam layer 610
is 2 inches, the thickness T.sub.a of the air barrier foam layer
614 is 3/8 inches and thickness T.sub.t of the topper foam layer
615 is 1 and 5/8 inches. Thus, the overall thickness T.sub.o of
mattress 600 is 10 inches.
[0054] While in one embodiment, as shown in FIG. 6a, the air
barrier foam 614 is positioned as the layer immediately underneath
the topper foam layer 615, in an alternate embodiment, the air
barrier foam 614 is sandwiched as a layer between the base foam
layer 604 and the foam core layer 610, as shown in FIG. 6b.
[0055] In one embodiment, side foam sections 603 and base foam
layer 604 of mattress 600 are comprised of high density
polyurethane foam. To provide adequate firmness and support, the
ILD for the side foam sections 603 and base foam layer 604 is kept
in the range of 20 to 40. In one embodiment, the high density
polyurethane foam is of the order of 32 ILD. In one embodiment, the
high density polyurethane foam is on the order of 32 ILD. In one
embodiment, core foam layer 610 and topper foam layer 615 are
comprised of a foam of a relatively lower density than the side
sections 603 and base foam layer 604, such as 5 lb pure visco foam,
which provides significant visco-elasticity. For the same purpose,
ILD for the core and topper foam layers is kept in the range of 12
to 16. In an additional embodiment, the density rating of the visco
foam is in the range of 2 lb to 6 lb.
[0056] Persons of ordinary skill in the art should note that the
densities and thicknesses above are exemplary only and in no way
are meant to be limiting to the invention. For example as shown in
FIG. 6c, in an embodiment, the overall thickness T.sub.o of the
mattress 600 depends on the thickness T.sub.s of the side sections
603, the thickness of the topper foam layer 615 denoted as T.sub.t
and the thickness T.sub.other, which represents an optional foam
layer(s) 620 placed over the topper foam layer 615. Thus, in this
case T.sub.o=T.sub.s+T.sub.t+T.sub.other. Thus, in one embodiment,
the overall thickness T.sub.o of mattress 600, in this case, is 13
inches. Also, for example, while side foam sections 603 and base
foam layer 604 are comprised of a high density polyurethane foam,
core foam layer 610 and topper foam layer 615 are of a
comparatively lower density. Thus, in one embodiment, side foam
sections 603 and base foam layer 604 are comprised polyurethane
foam having an ILD range of 20-40, while core foam layer 610 and
topper foam layer 615 are comprised of pure visco foam of 5 lb
density. Further, the additional topmost layer 620 may be comprised
of a foam having the relatively lowest density, such as 3 lb.
[0057] It should be appreciated that, in any of the aforementioned
embodiments, side sections 603 can be placed at each of the four
sides of the mattress, including the right, left, head, and foot
sides. In such a case, the core foam layer 610 is adjusted in size
to be accommodated in the space created by the four side
sections.
[0058] FIG. 7 illustrates yet another embodiment of the mattress of
the present invention. Referring to FIG. 7, mattress 700 includes
not only side rails 701 and 702, which are made up of a high
resiliency material such as polyurethane foam, but also includes
rails 703 and 704 at the head and foot of the mattress as well.
This configuration provides enough support at all the four edges of
the bed. The four edge rails are supported by a high resiliency
base foam structure (not shown), which forms the base of the
mattress in a manner similar to that described earlier with
reference to embodiments shown in FIGS. 3a, 3b, 5 and 6a. Further,
the four edge rails can be discrete pieces in one embodiment that
are bonded to a support base. In another embodiment, a single unit
of foam is shaped to have a base and four raised edge sections that
form the edge rails.
[0059] At the centre of the space created by the four high
resiliency edge rails 701, 702, 703 and 704, and on the top of the
support base of the mattress, is a core foam layer 705 comprising
material of relatively lower resiliency, such as pure viscoelastic
foam. As in previous embodiments, a foam topper layer (not shown),
also made up of a low resiliency material such as pure viscoelastic
foam rests on the top surface of central foam core layer 705 and
edge foam sections 701, 702, 703 and 704.
[0060] Thus, the base foam structure along with the edge sections
are made of more dense (and rigid) and/or more resilient foam
material while the core foam layer and the topper foam layer are
made of comparatively less dense and/or less resilient (and thus
softer) foam material. In addition, the core foam layer is, in one
embodiment, firmer in comparison to the topper foam layer. This
density variation across sections of the composite mattress 700 is
advantageous in that the softer upper layer(s) provide gentle
support to the entire body while the firmer bottom layer(s)
provides greater support to a heavier area of the body that sinks
deeper into the mattress. At the same time the substantially firmer
edge rails not only help prevent the feeling of falling off the
edge of the bed while sleeping on the sides, but also provide
sturdy support to the core foam layer and the topper foam
layer.
[0061] In one embodiment, the density of the material comprising
the head rail 703 is relatively higher than that of the material
comprising foot rail 704. This configuration is useful in
therapeutic conditions where better support is required for the
head and neck.
[0062] In the embodiment of FIG. 7, the thickness of the rigid edge
rails is designed to optimize comfort and support. Since thinner
rails provide inadequate support and too thick rails make the
mattress uncomfortable to sleep, therefore in one embodiment, the
thickness of edge rails is designed to be in the range of 1 to 6
inches, optimally 2-3 inches. Further, the thickness of edge rails
can be customized according to the requirement and user preference.
In one embodiment for example, the rails at the foot and head of
the mattress are less thick than at the sides.
[0063] Optionally, covers may be used to envelope the mattress of
the present invention. Referring back to FIG. 2a, 2b, in one
embodiment, the base foam structure comprising side foam sections
203 and base foam layer 204, along with the central foam core layer
210 are wrapped using a first cover (not shown) and the topper foam
layer 215 is wrapped using a second cover (not shown). In another
embodiment, a first cover (not shown) is used to wrap side foam
sections 203 and base foam layer 204, a second cover (not shown) is
used to wrap the central core foam layer 210 and a third cover (not
shown) is used for the topper foam layer 215.
[0064] Referring now to FIG. 5, in one embodiment, the base foam
structure 505, comprising the side foam sections 503 and base foam
504, along with the foam core 510 and the air barrier foam 514 are
wrapped using a first cover (not shown) and the topper foam layer
515 is wrapped using a second cover (not shown). In another
embodiment, a first cover (not shown) is used to wrap the base foam
structure 505, a second cover (not shown) is used to wrap the core
foam 510, a third cover (not shown) is used for the air barrier
foam 514 and a fourth cover (not shown) is used for the topper foam
layer 515.
[0065] For convenience of easy removal/changing the covers have
zippers, as is known in the art. The covers can be made of cotton,
which is breathable, absorbent and washable, or other permeable or
impermeable fabric such as wool, silk, linen, polyester fleece. In
one embodiment, the covers are fire retardant. For example,
flame-resistant covering may be made of cotton, linen, wool, silk,
nylon, an acrylic or other synthetic fabric that is impregnated
with a fire retardant compound such as, but not limited to, boric
acid (H.sub.3BO.sub.3), zinc borate, antimony trioxide
(Sb.sub.2O.sub.3), vinylidene chloride, decabromodiphenyl oxide
(DBDPO or Deca), Melamine or PVDC. Alternatively, flame-resistant
covering is made of a flame-retardant fabric such as, but not
limited to, a fabric made of para-aramid fibers.
[0066] The above examples are merely illustrative, and although
only a few embodiments of the present invention have been described
herein, it should be understood that the present invention might be
embodied in many other specific forms without departing from the
spirit or scope of the invention. Therefore, the present examples
and embodiments are to be considered as illustrative and not
restrictive, and the invention may be modified within the scope of
the appended claims.
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