U.S. patent application number 12/657568 was filed with the patent office on 2010-07-29 for anatomical, pressure-evenizing mattress overlay.
This patent application is currently assigned to MJD Innovations, L.L.C.. Invention is credited to Casey A. Dennis, Michael R. Dennis.
Application Number | 20100186172 12/657568 |
Document ID | / |
Family ID | 42352932 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100186172 |
Kind Code |
A1 |
Dennis; Casey A. ; et
al. |
July 29, 2010 |
Anatomical, pressure-evenizing mattress overlay
Abstract
A method and structure for furnishing pressure-evenized,
dynamic-reaction anatomical support. The method includes (a)
supporting the anatomy with a 100% open cell viscoelastic foam, and
(b) thereafter, and within the foam, reacting to both static and
dynamic, anatomically-produced foam indentations to expand and
contract cell-openness size, whereby deeper/sharper indentations
result in greater-size cell-openness. Such reacting includes
laterally stretching and flowing regions of the foam adjacent such
an indentation The overlay structure features (1) a
dynamic-response core expanse formed of a 100% open-cell,
compressible and flowable, polyurethane, viscoelastic foam
possessing a compressed, relaxed-state volume and (2) an
elastomeric, moisture-resistant coating, load-transmissively,
interfacially bonded to the entirety of the outside surface of the
core expanse to function as a dynamically-responsive unit with the
expanse. The coating possesses a relaxed-state prestressed tension
condition which is responsible for the expanse's compressed
condition.
Inventors: |
Dennis; Casey A.; (Sequim,
WA) ; Dennis; Michael R.; (St. Helens, OR) |
Correspondence
Address: |
ROBERT D. VARITZ, P.C.
4915 SE 33RD PLACE
PORTLAND
OR
97202
US
|
Assignee: |
MJD Innovations, L.L.C.
|
Family ID: |
42352932 |
Appl. No.: |
12/657568 |
Filed: |
January 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61206126 |
Jan 28, 2009 |
|
|
|
Current U.S.
Class: |
5/740 |
Current CPC
Class: |
A47C 27/14 20130101;
A47C 27/006 20130101 |
Class at
Publication: |
5/740 |
International
Class: |
A47C 27/14 20060101
A47C027/14; A47C 21/00 20060101 A47C021/00 |
Claims
1. An anatomical pressure-evenizing mattress overlay comprising a
dynamic-response core expanse having spaced, upper and lower,
surfaces and a perimetral edge extending between said surfaces,
formed of a 100% open-cell, compressible and flowable, viscoelastic
foam, and having a relaxed-state volume in the overlay which is
prestressed, and about 8-10% compressed, thus to create a
pre-compression condition in the expanse, and an elastomeric,
moisture-resistant coating, load-transmissively bonded to the
entirety of the outside of said expanse to function as a
dynamically-responsive unit with the expanse, and possessing a
relaxed-state internal prestressed tension condition.
2. The overlay of claim 1, wherein said core expanse exhibits a
compressive-deflection vs. compression-force curve which includes
an extremely linear region over which a relatively wide change in
compressive deflection is accompanied by what turns out to be an
anatomically insignificant change in compression pressure.
3. The overlay of claim 1, wherein said core expanse is
specifically form of a polyurethane material.
4. The overlay of claim 1, wherein said upper and lower surfaces
are, allover, substantially equidistant.
5. The overlay of claim 1, wherein said expanse has a thickness
throughout of about 1-inches, and said coating has a thickness,
throughout, of about 0.015-inches.
6. The overlay of claim 1, wherein said coating is formed with
fifteen, approximately 0.001-inches thick cured, curable initially
wet vinyl sublayers initially having, between next-adjacent
sublayers, wet, interfacial surfaces of joinder.
7. The overlay of claim 1 which further comprises, for said
coating-covered core expanse, a removeably fittable/installable,
generally form-fitting, allover composite-fabric jacket having an
upper-surface portion formed of a selected, lower-friction
material, and a lower-surface portion formed of a selected, higher
friction material.
8. The overlay of claim 7, wherein said lower-friction material is
formed of a woven polyester fabric.
9. The overlay of claim 7, wherein said higher-friction material is
formed of a polyurethane-coated, polyester-knit fabric.
10. The overlay of claim 9, wherein said lower-friction material is
formed of a polyurethane-coated, polyester-knit fabric.
11. An anatomical pressure-evenizing mattress overlay comprising a
core expanse of single-density, 100%, open-cell, compressible and
flowable, polyurethane, viscoelastic foam, and a gas-breathable,
moisture-resistant, elastomeric coating extending over the entirety
of the surface area of said core expanse, and interfacially,
mechanically bonded to said surface area, said coating being
everywhere in tension and placing said core expanse everywhere in
compression.
12. A method for furnishing pressure-evenized, dynamic-reaction
support for the anatomy comprising supporting the anatomy with a
100% open cell viscoelastic foam, and following said supporting,
and within the supporting foam, reacting therein to both static and
dynamic, anatomical-unevenness-produced indentations in the foam to
expand and contract cell-openness size, whereby deeper and sharper
indentations result in greater cell-openness size.
13. The method of claim 12, wherein said reacting includes
laterally stretching and laterally flowing regions of the foam
adjacent such an indentation.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims filing-date priority to prior-filed,
currently copending U.S. Provisional Patent Application Ser. No.
61/206,126, filed Jan. 28, 2009, for "Anti-Decubitus-Injury
Mattress Overlay". The entire disclosure content of this
prior-filed application is hereby incorporated herein by
reference.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The present invention pertains to a special-purpose,
special-capability, breathable, moisture-controlling,
anatomical-support, pressure-evenizing, "mattress overlay" intended
to be placed on top of, and used in conjunction with, an
underlying, yieldable support surface, such as that provided by a
mattress, for the purpose of furnishing "direct",
pressure-evenizing under-support for a substantially bed-ridden
person. It is specifically designed, as will be explained more
fully below, with a thinness suitable, with appropriate, yieldable
under-support, for handling persons weighing up to about 250-lbs.
It is definitively not designed to be used alone as a support on
top of any rigid, underlying surface; nor is it intended to be a
"stand-alone" support structure, such as a mattress, per se. Where
heavier persons need to be accommodated, this may be done, as will
also be explained more fully below, by placing the overlay on top
of an additional, bariatric, under-support structure.
[0003] Accordingly, the herein-proposed overlay, as will be
developed further herein, has an important, intentional, preferred
quality of relative thinness preferably (no more than about
1-inches), and this important thinness quality militates against
its utilization respecting the "not-designed-for" uses just
mentioned. The term "bed-ridden" as used herein as a "person
characterization" is intended broadly to include a wide range of
differently convalescing persons who may spend significant amounts
of extended, body-support time not only specifically in hospital
beds, but also in conjunction with other bed-like mattress
structures.
[0004] Speaking more specifically about the invention, and about
its remarkable, demonstrated capability, it, the proposed "mattress
overlay", has as its special purpose the dramatic minimization, and
in many instances the complete prevention, of the onset and
development of decubitus ulcers(sores)--medical conditions that
lead to dangerous and potentially lethal injuries which come from
long-term body-rest/support conditions. Accordingly, the overlay of
the present invention is naturally, and particularly, well suited
for placement on top of conventional, long-term,
person/patient-support mattresses, such as hospital-bed mattresses.
While such a hospital-bed setting clearly presents an ideal use
environment for the present invention, the defining term "mattress
overlay" is intended herein to refer to any overlay structure
constructed in accordance with the special and unique features of
the present invention which may be shaped, sized, etc., for use not
only on top of an underlying, conventional mattress structure, per
se, but also in other similar environments where nonambulatory
people, such as convalescing patients, may lie recurrently
supported for long periods of time. The above-expressed concept of
"direct", underlying, person support, while it could (and can)
include the concept of direct-to-skin contact support, herein more
typically means support which is furnished, for example, "directly
through" clothing (such pajamas, a hospital gown, etc.), through a
bed sheet, or through some combination of these things.
[0005] Regarding the above-mentioned special purpose of the present
invention, it is now, and has been for some time, well recognized
that the medical issue involving the development of decubitus
ulcers in bed-ridden, etc., patients, often those people who are
still in the environment of a hospital recovering from some medical
event or condition, is an extremely serious problem--a problem
which has recently caught the significant negative attention of
medical-institutional (and related) insurance agencies who have
come to recognize that prevention of the development of such ulcers
is, in fact, quite possible, though through conventional approaches
very challenging. This "negative attention" has translated itself,
among other things, into agency refusals to offer/provide relevant
insurance coverage. While the just-mentioned term "quite possible"
is indeed true, real prevention--that is, effective real
prevention--heretofore has been almost prohibitively expensive
because of the fact that such prevention has, in reality, required
substantial, frequent, personnel-intensive, one-to-one, or
more-to-one, personal attendance to the changing of the resting
"positions" of "bed-ridden" persons at risk.
[0006] The decubitus ulcer problem is recognized today as being one
of the most serious problems facing hospital and medical-care
facilities, and these skilled care facilities are openly waging a
fierce battle with state and federal agencies and insurance
companies over who should pay the enormous costs in the treatment
of this "new epidemic."
[0007] In this setting, the prior art, of which we are aware, that
has been aimed at addressing the "decubitus-injury" problem is rich
with purportedly effective, proposed approaches for resolving it.
In practice, none appears to be particularly successful or
satisfactory, owing, as we perceive it, to the significant and
apparent failure to grasp a full understanding of the body-support
environmental contact conditions which must exist if decubitus
"onset" is to be avoided. The present invention is based upon, and
"possesses", this understanding, and in months of experimental use,
involving thousands of "real-life" patient-support hours, and
hundreds of bed-ridden patients, there has not been one single
instance of decubitus-injury onset.
[0008] Notable, known, patent-related pieces of this prior art are
identified herein immediately below:
[0009] U.S. Patent Application Publication No. 2001/0034908 A1 of
Duly, for "Mattress"; U.S. Pat. No. 5,031,261 to Fenner, Sr., for
"Mattress Overlay For Avoidance of Decubitus Ulcers"; U.S. Pat. No.
5,077,849 to Farley, for "Anatomically Conformable Foam Support
Pad"; U.S. Pat. No. 6,052,851 to Kohnle, for "Mattress For
Minimizing Decubitus Ulcers"; U.S. Pat. No. 7,356,863 to Oprandi,
for "Mattress Pad".
[0010] While these prior-art approaches address, and attempt to
tackle with resolution, certain technical medical issues and
conditions that can lead to the development of decubitus injury (we
will hereinafter use for such an injury the term "decubitus
ulcer"), clearly taking aim, in the bargain, so to speak, at
successfully minimizing costly medical-personnel attention to
at-risk individuals, and repeating with emphasis what we have said
above, as far as we can tell, no one has successfully developed a
truly effective support structure and/or methodology which
has(have) the capabilities of substantially eliminating, in most
instances, the likelihood that such a decubitus ulcer will
develop.
[0011] The present invention dramatically changes this situation.
While readings and study of this prior, when compared with a
reading of the present invention disclosure may appear at first
glance, and on certain points, to reveal only subtle differences,
in reality these differences, in terms of solving the problem of
decubitus onset, are anything but subtle. Put another way, these
differences "make the difference"!
[0012] While there are probably many issues that are usefully
addressable in terms of preventing decubitus ulcers, the three, key
considerations which we specially recognize in the methodology and
structure of the present invention involve: (a) (1) avoiding even
very short-term (minutes) of high applied anatomical pressure, (2)
at all times pressure-evenizing the contact-loading characteristics
which define how the anatomy of a bed-ridden patient is supported,
and (3) specifically producing a loading condition, static and
dynamic, whereby there exist substantially no notably high-pressure
points (preferably none exceeding about 32-mm Hg, and even more
preferably not exceeding about 20-mm Hg), and definitively no
conditions involving a projecting portion of the person's anatomy
(i.e., a protuberance) bottoming out against either a non-yielding,
or relatively non-yielding, underlying support surface, or in any
manner significantly raising (de-evenizing) anatomical support
pressure; (b) dealing effectively with the handling (removing) of
moisture which may develop in the contact interface between a
person's anatomy and the underlying support structure, and (c),
very importantly, providing effective, ventilating airflow (more
broadly, gas flow) in the region immediately beneath the contact
supported anatomy so as to avoid the development of hot-spots and
overheating, and especially recognizing that those portion of a
supported anatomy, such as bony prominences, which create notable,
downward "indentations" in an underlying support structure should
be offered proportionally larger access to air (gas) flow.
[0013] Stressing this just-identified, third, airflow-associated
concern, and repeating with attention-commanding emphasis the
"proportionally" greater airflow comment just made above, it is
especially relevant that the points/areas/regions of underlying
anatomical support which must deal with the mentioned, notable,
anatomical protuberances, and especially with pronounced (i.e.,
relatively "sharp") protuberances, be designed to furnish enhanced
rather than more constricted airflow. Put another way such
protuberance-support areas are the ones that potentially define the
greatest risk for decubitus-ulcer development, and as we have
discovered, are the areas where the most robust ventilating airflow
needs to exist. Generally speaking, the greater the size and/or
"sharpness" of the protuberance, and thus the greater and the
deeper and the more angular the resulting support-surface
indentation, the greater the need for enhanced airflow.
[0014] Unfortunately, known and proposed prior art manners of
attacking the decubitus-ulcer problem do not recognize this
special, anatomical-protuberance-support observation of ours, and
failing that observation, actually propose supposedly
problem-resolving body-support structures and associated
methodologies which exacerbate the airflow problem associated with
protuberance support by reacting to downward protuberances with
either no attention paid to airflow, or even worse, increased
constriction to airflow.
[0015] With this background in mind, the present invention, in its
structural character, takes the form of an anatomical
pressure-evenizing mattress overlay including (a) a
dynamic-response, preferably uniform-thickness core expanse having
spaced, upper and lower, surfaces and a perimetral edge extending
between these surfaces, formed of a 100% open-cell, uniform-density
compressible and flowable, viscoelastic foam, and having a
"relaxed-state" volume in the overlay which is prestressed, by
being about 8-10% compressed, to create a pre-compression condition
in the expanse, and (b) an elastomeric, moisture-resistant,
gas-breathable vinyl coating, which is load-transmissively,
interfacially bonded to the entirety of the outside surface area of
the core expanse to function as a dynamically-responsive unit with
the expanse, with this coating possessing a "relaxed-state",
internal, prestressed tension condition which is responsible for
the prestressed compression condition in the core expanse. The term
"relaxed-state" herein is used to refer to the conditions of the
components (two) making up the pad when the pad is in a non-use
situation.
[0016] The core expanse is specifically and preferably formed of a
specific-character, solid-phase, single-component, single-density,
polyurethane material, shaped with its upper and lower surfaces
substantially equidistant (i.e., the core expanse has preferably a
uniform thickness) to give the overlay, as a whole, a substantially
uniform thickness of no more than about 1-inches, with the coating
having a contributing thickness throughout of only about
0.015-inches.
[0017] For important structural and performance reasons which will
be explained later herein, the coating is formed preferably with
fifteen, approximately 0.001-inches thick, cured, sublayers,
spray-applied, one over another, under circumstances where the
"previously applied", next-spray-receiving layer is still wet and
not yet cured. This layer-generating approach produces,
structurally, a final, cured, layered coating having, between all
next-adjacent sublayers, what we refer to structurally herein as
being finally cured, but initially wet, interfacial surfaces of
joinder. We have found that this special type of interfacial
joinder structure enhances not only the air/gas breathability of
the overall coating, but also, importantly, the controlled
shrinkage of the coating to produce the desired level of
coating-internal tension, and core-expanse-internal compression.
The detailed description of the invention which follows below will
describe fully the importance attached to the matter of
core-expanse-material flowability, coating tension, core-expanse
compression, and coating-core-expanse mechanical binding to one
another.
[0018] The overlay, per se, which is elongate and generally planar
in nature, has no preferential upper or lower end, and no
preferential top or bottom face, or side. It can, accordingly,
confidently be placed with any suitable orientation on an
appropriate supporting under-structure.
[0019] The overlay structure of the invention further includes, for
the coating-covered core expanse, a removeably
fittable/installable, generally form-fitting, allover
composite-fabric jacket having an upper-surface portion formed of a
selected, lower-friction material, and a lower-surface portion
formed of a selected, higher friction material. The lower-friction
material is formed of a woven polyester fabric, and the
higher-friction material is formed of a polyurethane-coated,
polyester-knit fabric. The term "composite-fabric" is used herein
to refer to the differentiated-fabric-material character of the
jacket.
[0020] From a methodologic general perspective, the invention
involves a method for furnishing pressure-evenized,
dynamic-reaction support for the anatomy including (a) supporting
the anatomy with a 100% open cell, polyurethane, viscoelastic foam,
and following such supporting, and within the supporting foam,
reacting therein to both static and dynamic,
anatomical-unevenness-produced indentations in the foam to expand
and contract foam cell-openness size, whereby deeper and sharper
foam indentations result in greater cell-openness size.
[0021] These and other features and advantages offered by the
present invention will become more fully apparent as the detailed
description which now follows is read in conjunction with the
accompanying drawings.
DESCRIPTIONS OF THE DRAWINGS
[0022] FIG. 1 is a simplified, isometric view of an anatomical
pressure-evenizing mattress overlay constructed in accordance with
a preferred and best-mode embodiment of the present invention
resting upon a fragmentarily shown hospital-bed mattress, and with
a portion of one corner of the illustrated overlay broken away to
illustrate details of internal construction.
[0023] FIG. 2 is a larger scale, fragmentary, cross-sectional view
taken generally along the line 2-2 in FIG. 1.
[0024] FIG. 3 is an even larger-scale, fragmentary illustration of
the region generally embraced by the two curved arrows 3-3 in FIG.
2.
[0025] FIG. 4 is a simplified, fragmentary view, drawn on about the
same scale which is employed in FIG. 2, illustrating anatomical,
load-bearing response of the overlay of FIGS. 1-3, inclusive, and
especially showing how the dynamic-response core of the overlay of
the present invention responds to such loading.
[0026] FIG. 5 is a simplified, isometric view, drawn on about the
same scale as that which is employed in FIG. 1, illustrating an
installable/removable fabric jacket having differentiated upper and
lower jacket portions, designed, in a form-fitting fashion, to
receive, and to be employed with, the overlay structure of FIGS.
1-4, inclusive.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Turning attention now to the drawings, and referring first
of all to FIGS. 1-3, inclusive, indicated generally at 10 is a
preferred and best-mode embodiment of an anatomical,
pressure-evenizing mattress overlay constructed in accordance with
the present invention. Overlay 10 herein has an overall thickness
of about 1-inches (a preferred maximum thickness), a lateral width
of about 36-inches, and a length of about 75-inches. Overlay 10 is
formed, basically, from two different components, or portions,
including a single-piece, dynamic-response core expanse 12, and an
elastomeric, air-breathable, moisture-resistant coating 14 which,
as will shortly be explained, is load-transmissively
(mechanically), interfacially (face-to-face) bonded to the entirety
of the outside broad-planar and edge surface area of expanse
12.
[0028] In FIGS. 1 and 2, overlay 10 is shown resting upon a
hospital-bed mattress of conventional construction shown generally
and fragmentarily only at 16 in these two drawing figures. As has
been mentioned earlier herein, the mattress overlay of this
invention need not necessarily be used in the setting of a
conventional, hospital, bedding mattress, but may also be used,
appropriately perimetrally shaped, to fit into other environments
involving convalescing patients. In all instances, it is important
that the mattress overlay of this invention be supported upon a
mattress-like support, or other, similar, suitably yieldable
understructure in order to prevent core expanse 12 from bottoming
out.
[0029] In this context, the about 1-inches thickness proposed
herein as being preferable for the core expanse has been chosen for
several reasons, one of which is that, when properly
under-supported, and as above described, it will readily handle a
person weighing about 250-lbs, and will also successfully deal,
without bottoming out, with notably projecting, angular portions of
the anatomy even involving persons of such weight. Under
circumstances where an especially heavy person, for example someone
who weighs more than about 250-pounds and up to about 450-lbs, is
to be supported in accordance with practice of the invention, it is
important that the overlay not be placed upon a hard and
non-yielding undersurface, or be used alone as a mattress with
stiff under-support. Such conditions could easily lead to bottoming
out. Rather the overlay should be placed on top of some auxiliary,
underlying, bariatric, yieldable supporting structure.
[0030] In addition to the mattress overlay as a whole having a
preferred thickness of about 1-inches in order to prevent a
bottoming out situation, another important reason for choosing an
overlay thickness limited to about 1-inches is that this is a
thickness which works well to assure maximum availability of the
significant air-breathability capabilities of the selected overlay
components.
[0031] According to one very important feature of the present
invention, core expanse 12 is formed of a 100% open-cell,
single-density, viscoelastic foam most preferably made from the
product known as #5010 CF Visco, polyurethane, Domfoam made by
Domfoam International, Inc. in Montreal Quebec, Canada. This foam
is both compressible and flowable. Significantly, this foam which
has been chosen for the core expanse has another, very important,
internal structural character whereby, under changing
compression-pressure conditions, it exhibits a
compressive-deflection vs. compression-force curve which includes
an extremely linear region over which a relatively wide change in
compressive deflection is accompanied by what turns out to be an
anatomically insignificant (i.e., only slightly perceptible) change
in compression pressure. This feature plays a very important role
in assuring evenized support pressure applied statically and
dynamically to the underside of a supported anatomy,
notwithstanding the presences of, say, any bony anatomical
protrusions.
[0032] For a reason which will now be explained, and as has already
been mentioned above, core expanse 12, within the overall structure
of overlay 10, is in a pre-stressed compressed condition, with a
"relaxed-state" compression internally of about 8-10%. This
compression is brought about by virtue of the presence of allover
overcoating by coating 14 which is a multi-sublayered, sprayed-on
vinyl coating prepared with an overall thickness of about
0.015-inches from a vinyl material preferably that made and sold by
PlastiDip International in Blaine, Minn. under the identity
Miraculon PDF-830. As was mentioned earlier, coating 14 is prepared
with fifteen 0.001-inches thickness layers in a special manner to
ensure two of several important features of the overcoating, one of
which is that special inter-sublayer joinder exists between each of
the sprayed-on sublayers to improve air-breathability of the
coating, and another of which is to create a coating which, when
completed, demonstrates a controlled shrinkage which is responsible
for placing core expanse 12 into compression, and the coating into
a prestressed, tensed condition.
[0033] Directing attention for a moment to FIG. 3, here a fragment
of the fifteen-sublayer construction of coating 14 is illustrated.
In this figure, one can see several of these sublayers, including a
final outer sublayer 14a, a next adjacent sublayer 14b, and in
interfacial bond 14c which lies between sublayers 14a, 14b. This
interfacial bond is referred to herein as "initially wet",
interfacial surfaces of joinder. With core expanse 12 prepared
appropriately with the appropriate dimensions, coating 14 is then
applied in fifteen, successive spraying operations wherein the very
thin vinyl sublayers that ultimately make up the entirety of
coating 14 are applied, one after another in a succession whereby
each "next-adjacent" sublayer is sprayed onto the receiving
sublayer under circumstances with the vinyl material in the latter
(i.e., the receiving sublayer) still in a wet and not fully cured
state. This important preparation consideration results in the
resulting structural joinder which develops in the interfacial
region between the individual sublayers in coating 14 offering
improved breathability in the final structure of coating 14, and
further, promoting appropriately controlled shrinkage of coating 14
as a whole to create the different pre-stressed compression and
tension conditions mentioned above for the core expanse and the
coating, respectively.
[0034] Importantly, thin application of the first-to-be-sprayed-on
sublayers in coating 14 causes the coating as a whole to bonds
robustly mechanically (in a manner which we refer to as
load-transmissively) to the entire outside surface area of the core
expanse, with the result that the localized regions of joinder of
the core expanse and the coating function essentially as a unit
everywhere within the overlay.
[0035] Adding reference now to FIG. 4 in connection with FIG. 1,
this bonding condition produces an "in-use" action, extremely
important in the behavior of overlay 10, wherein expansive
stretching of the coating, such as that which occurs, for example,
when the anatomy, and particularly a sharp, anatomical protuberance
therein, depresses the overlay support surface (see arrow 18 in
these two drawing figures), pulls on the bonded core expanse, and
causes (a) core-openness size in that pulled-on and resultingly
expanded, core-expanse region to enlarge, and (b) airflow openness
in the coating to increase locally, thus immediately promoting
increased airflow capability and activity in that region. Prestress
compression in the core expanse importantly aids in this action,
since that compression urges the core expanse to swell
non-resistively, and expand. When the protuberance represented by
arrow 18 engages the overlay, and with understanding that things
are purposely illustrated exaggeratedly in FIG. 4, it produces a
significant depression 14A in coating 14, and a matching depression
in the upper surface of core expanse 12. Given the modest thickness
of the core expanse, this depression "telegraphs" to the immediate
underside of the expanse to produce the gentle downward bulging in
coating 14 shown at 14B.
[0036] This "depression/bulging" condition is characterized, of
course, by an expanding and stretching of the coating at the 14A,
14B locations therein, and attendant increasing of the there-local
airflow permeability of the coating. This expanding and stretching
causes related, outward, lateral "dragging" of the bonded core
expanse, aided in that "dragging" by the relaxation of compression
in that expanse. The squeezing which results in the core expanse
between locations 14A, 14B produces slight, lateral, outward
flowing of the expanse as indicated by arrows 20, 22, with
outwardly flowed core expanse-material represented in the two,
angular, lightly shaded region of that expanse shown at 24. 26.
[0037] It is these air-management features of the invention,
promoted by relative thinness in the overall overlay, by the
mechanical bondedness which exists between the core expanse and the
coating, and the pre-compression/pretension conditions extant in
the core expanse and coating, respectively, which cause the overlay
to adapt needed anatomical-support airflow in a manner whereby
those supported areas of the anatomy which should receive enhanced
airflow in the context of being protected against "decubitus onset"
do receive such enhanced treatment. This adaptation behavior is
dynamic, in the sense that changes in supported anatomy position
are followed appropriately and instantly in the context of
most-needed airflow availability.
[0038] Prior art structures that are known to us have no such
capability for offering this important decubitus-injury-minimizing
behavior. In many instances, unfortunately, prior art structures
often respond to support indentation in a harmful manner which
closes off support-offering airflow capability the deeper/larger
the indentation which exists.
[0039] Turning attention now to FIG. 5, indicated generally at 28
is a removeably fittable/installable, generally form-fitting,
allover composite-fabric, freely air/gas-breathable jacket having
an upper-surface portion formed of a selected, lower-friction
material, and a lower-surface portion formed of a selected, higher
friction material, which jacket may be used under certain
circumstances now to be explained as a receiving jacket for overlay
10. This jacket is especially useful in circumstances where it is
desired that the lower side, effectively, of the overlay have a
higher-frictioning quality so that slippage on top of an underlying
support structure, such as a hospital-bed mattress, cannot easily
occur, and at the same time that the upper side, effectively, of
the overlay have a notably lower-friction quality so that a patient
lying on the overlay may easily be adjusted in position by gentle
sliding on the overlay if and when it becomes necessary to change
patient position. Accordingly, jacket 28 is formed with
differentiated-material upper and lower surface portions 30, 32
which furnish these differentiated frictioning qualities.
[0040] More specifically, upper surface, lower-friction portion 30
is formed of a freely air/gas-breathable, woven, polyester fabric,
made by Global Textile Partners based in Gloversville, N.Y., and
identified as TF-64 Polyester. This material very adequately
provides for a low-friction surface next to the skin or
bedding/clothing materials. and helps to minimize friction and
shear forces on the skin. Additionally, it aids caregivers by
allowing for easier sliding transfers of patients who are unable to
reposition themselves. Further, it also provides a high-rate
wicking material next to or near the skin--a feature which aids in
removal of potentially problem-generating moisture.
[0041] The lower surface, higher-friction portion 32 is formed of a
polyurethane-coated, polyester-knit fabric, made by Harrison
Technologies, Inc., in Broadalbin, N.Y., and identified as
Pigskin-Knew-Tek Polyurethane.
[0042] These two particular materials and their respective
manufacturers have been selected preferably because of the fact
that these specific materials function very well for the intended
purposes just expressed above. Those skilled in the art will
recognize that other, similar, friction-character materials may be
employed, so long as these materials collectively do not impede in
any appreciable way the intended airflow capability of overlay
10.
[0043] The upper and lower surface portions, or components, in
jacket 28 are suitably edge joined, with at least a portion (three
lateral sides herein) of edge joinder being created through a
zipper structure, such as that generally indicated at 34. In FIG.
5, jacket 28 has been illustrated with one end part of the upper
component unzipped, so to speak, from the lower component, and
folded back somewhat to provide insertion and removal access for
overlay 10 which is illustrated fragmentarily by a dashed line in
FIG. 5.
[0044] Where it is desired that the overlay of the present
invention be employed with a person whose weight lies in the range,
for example, of about 250-lbs to about 450-lbs, a suitable
bariatric under-support structure should be employed. Preferably,
this structure will have essentially the same perimetral outline as
that of the supported overlay, and will furnish appropriate
yieldable under-support to prevent bottoming out of the core
expanse in the supported overlay. While many different kinds of
such bariatric under-support structures may be employed, we have
experimented successfully with a 1-inches thick pad formed of two
layers of different, rate-sensitive, viscoelastic foam materials
specifically made by AEARO Specialty Composites in Indianapolis
Ind., with an upper layer in this pad having a thickness of about
0.75-inches and being formed of the material sold as Confor CF-42
foam, joined by adhesive bonding to a lower layer of the material
sold as Confor CF-45 foam having a thickness of about 0.25-inches.
There are, of course, many other materials which may be employed
successfully for such a bariatric under-support structure.
[0045] Thus the present invention offers an anatomical
pressure-evenizing mattress overlay including (1) a
dynamic-response core expanse having spaced, upper and lower,
surfaces and a perimetral edge extending between these surfaces,
formed of a 100% open-cell, compressible and flowable, viscoelastic
foam, and having a relaxed-state volume in the overlay which is
prestressed, and about 8-10% compressed, thus to create a
pre-compression condition in the expanse, and (2) an elastomeric,
moisture-resistant coating, load-transmissively bonded to the
entirety of the outside of the core expanse to function as a
dynamically-responsive unit with the expanse, and possessing a
relaxed-state internal prestressed tension condition.
[0046] Within this structure, the core expanse exhibits a
compressive-deflection vs. compression-force curve which includes
an extremely linear region over which a relatively wide change in
compressive deflection is accompanied by an anatomically
insignificant change in compression pressure.
[0047] The overlay of the invention further optionally includes,
for the coating-covered core expanse, a removeably
fittable/installable, generally form-fitting, allover
composite-fabric jacket having an upper-surface portion formed of a
selected, lower-friction material, and a lower-surface portion
formed of a selected, higher friction material.
[0048] The methodology of the invention feature's a method for
furnishing moisture-removing, pressure-evenized, dynamic-reaction
support for the anatomy, including the steps of (a) supporting the
anatomy with a 100% open cell viscoelastic foam, and (b) following
such supporting, and within the supporting foam, reacting therein
to both static and dynamic, anatomical-unevenness-produced
indentations in the foam to expand and contract cell-openness size,
whereby deeper and sharper indentations result in greater
cell-openness size. With regard to this methodology, the reacting
step includes laterally stretching and laterally flowing regions of
the foam adjacent such indentations.
[0049] Thus, a unique mattress overlay structure, and a related
methodology, aimed with a very particular focus on helping to
resolve the decubitus ulcer/injury problem have thus been
illustrated and described herein, with certain variations and
modifications suggested. Among the important factors relating to
resolving this very dangerous and widespread kind of injury,
namely, (a) paying close attention to furnishing support for the
anatomy with an overall, evenized pressure which falls within a
certain, identified range of pressures, (b) managing moisture
withdrawal from the interface between the overlay support structure
and the anatomy, and (c), extremely importantly, furnishing
adequate cooling airflow to the supported anatomy, all are
dramatically dealt with by the present invention. This
"dramatically dealt with" comment is strikingly supported by the
fact that, as was mentioned earlier herein, in various,
`real-life", trial settings wherein many patients-support hours
have been monitored in the testing of this invention, there has not
occurred a single onset of a decubitus injury.
[0050] As has been pointed out with great particularity, the unique
structure of the present mattress overlay includes a special core
foam material which is completely 100% open-celled in nature, and
which is nominally under compression, coated by a very thin,
moisture-resistant, gas-breathable elastomeric layer which is
bonded tenaciously (interfacially, mechanically bonded) to the
entire surface of core foam. This unique collaborative union of
structures results in the occurrence of a very special performance
regarding anatomically-cooling airflow, wherein the deeper the
indentation produced in the overlay by a portion of the body
supported on it, the greater the "effective openness" of both the
supporting core foam material and the overlay material, a behavior
which directly, proportionately enhances airflow in the region, or
regions, of such indentation, or indentations.
[0051] Accordingly, while a preferred and best mode embodiment of,
and manner of practicing, the present invention have been
illustrated and described herein, and certain variations and
modifications suggested, we appreciate that other variations and
modifications may be made without departing from the spirit of the
invention, and it is our intention that all of the claims to
invention will be construed as covering all such other variations
and modifications.
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