U.S. patent application number 10/156074 was filed with the patent office on 2002-10-24 for body-contact protective interface structure and method.
Invention is credited to Dennis, Michael R., Paasche, Gerhard, Tucker, Michael W..
Application Number | 20020152542 10/156074 |
Document ID | / |
Family ID | 22273586 |
Filed Date | 2002-10-24 |
United States Patent
Application |
20020152542 |
Kind Code |
A1 |
Dennis, Michael R. ; et
al. |
October 24, 2002 |
Body-contact protective interface structure and method
Abstract
A plural-layer body-contacting protective and cushioning
interface structure. This structure has a body-facing side which
contacts the body, and an opposite side, and intermediate these
sides, in one form of the structure, is a moisture-wicking layer,
next a moisture-blocking, gas-permeable barrier layer adjacent the
moisture-wicking layer, and next, an acceleration-rate-sensitive
cushioning layer. In some applications, the moisture-wicking layer
is omitted.
Inventors: |
Dennis, Michael R.;
(Scappoose, OR) ; Tucker, Michael W.; (Beaverton,
OR) ; Paasche, Gerhard; (Scappoose, OR) |
Correspondence
Address: |
ROBERT D. VARITZ, P.C.
2007 S.E. GRANT STREET
PORTLAND
OR
97214
US
|
Family ID: |
22273586 |
Appl. No.: |
10/156074 |
Filed: |
May 27, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10156074 |
May 27, 2002 |
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09942987 |
Aug 29, 2001 |
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09942987 |
Aug 29, 2001 |
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09390518 |
Sep 3, 1999 |
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60099208 |
Sep 3, 1998 |
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Current U.S.
Class: |
2/414 |
Current CPC
Class: |
B32B 25/08 20130101;
B32B 2307/724 20130101; B32B 33/00 20130101; B32B 2437/04 20130101;
B32B 3/26 20130101; A42B 3/125 20130101; A42B 3/127 20130101; A42B
3/12 20130101; A42B 3/121 20130101; Y10T 428/249953 20150401; B32B
2307/7246 20130101 |
Class at
Publication: |
2/414 |
International
Class: |
A42B 003/00 |
Claims
We claim:
1. A layered, body-contacting, cushioning interface structure
having a body-facing side and a load-facing side, said interface
structure, progressing thereinto from a location which is adjacent
its said body-facing side, and toward its said load-facing side,
comprising a moisture-wicking layer, a fully moisture-proof,
non-perforated but gas-permeable barrier layer which blocks
completely any flow of moisture through the barrier layer, and a
viscoelastic cushioning structure.
2. A body-contacting cushioning interface structure comprising a
moisture-impervious, gas-permeable, deformable container, and an
acceleration-rate-sensitive, deformable, cushioning core disposed
within said container.
3. The interface structure of claim 2, wherein said cushioning core
is formed of a viscoelastic material.
4. A layered body-contacting protective structure having a
body-facing side and an opposite site, said structure, progressing
thereto from a location which is adjacent its said body-facing
side, and toward its said opposite side, comprising, a fully
moisture-proof, non-perforated but gas-permeable barrier layer
which blocks completely any flow of moisture through the barrier
layer, and an acceleration-rate-sensitive layer disposed adjacent
said barrier layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application from U.S.
patent application Ser. No. 09/942,987, filed Aug. 29, 2001,
entitled "Body-Contact Cushioning Interface Structure and Method",
which is a continuation from U.S. patent application Ser. No.
09/390,518, filed Sep. 3, 1999, entitled "Body-Contact Cushioning
Interface Structure", which application claims priority to U.S.
Provisional Application Serial No. 60/099,208, filed Sep. 3, 1998,
entitled "Body Contact System and Structure for Wearable Garments,
such as a Helmet."
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The present invention relates to a human-body-contact,
protective and cushioning interface structure. More particularly,
it relates to such a structure which is designed to be interposed
the body and some external structure which is worn on or attached
to the body, and through which various kinds of loads (such as
shock, general wearing-pressure related, and gravitational) may be
applied to the body. While there are many applications wherein the
structure of the present invention can offer distinct advantages,
one preferred embodiment of the invention is described herein
specifically (for illustration purposes) in the setting of a
helmet, such as a military helmet, with respect to which the
invention has been found to furnish particular utility. An
alternative preferred embodiment, referred to herein as a layered
body-contacting protective structure, is also described which
addresses the situation referred to above as "general
wearing-pressure", and very specifically to use of the invention as
a protective covering and "dressing" (bandage) over a wound which
is healing, and which requires some binding, as by tape attached to
the body, without appreciable occlusion of blood vessels that
supply a necessary flow of blood in the region of the wound.
[0003] Describing the invention first with reference to the
conventional "military helmet" environment, this environment is
very demonstrative of the issues that are successfully addressed by
the present invention. For example, the current U.S.-issue infantry
helmet utilizes an internal webbing system combined with a
removable leather liner to suspend the helmet on the wearer's head.
Airspace between the webbing and the shell of the helmet greatly
contributes to the ballistic and cooling capabilities of the
helmet, but the webbing system has proven consistently to be quite
uncomfortable, and thus to be the source of many complaints from
users.
[0004] Generally speaking, such discomfort comes about principally
because of localized capillary circulation loss caused by localized
high-pressure points that exist in the contact interface between
the helmet and the head. These pressure points come about typically
because of poor conformation (uneven pressure distribution) of the
usual web-borne head-contacting structure and the shape of the
head. Such pressure points generate the complained-of discomfort
and pain by creating localized low-blood-concentration ischemia
regions in the head. In fact, and as a momentary reminder here that
the invention has an application in the environment of bandaging,
there are many circumstances wherein pressure applications to the
body challenge and minimize blood flow in the associated region of
the body. For example, many people experience discomforting (or
otherwise negative) blood-flow diminution at a location where
particularly tight conventional bandaging has been applied, as by
contact taping. This situation will be addressed later herein.
[0005] The structure of the present invention offers improvements
in all of these areas of interest. This structure, in one preferred
form of the invention, features a novel, multilayered, web-like
cushioning structure which includes different "focused" layer
components that individually address (1) conformance-comfort and
ballistic behaviors, (2) moisture-wicking and cooling behaviors,
and (3) full moisture-barriering, nonetheless coupled with
substantially full gas-flow-enabling, behavior that both guard and
enhance the performances associated with matters (1) and (2). The
structure of the invention, in relation to the matters of ballistic
behavior and comfort, effectively minimizes, substantially to
beyond notice, localized high-pressure contact conditions which are
the principal creators of discomfort. In the bargain, so-to-speak,
of dealing with this issue, the same structural features which
vanquish discomfort promote significantly improved ballistic
response. Notably, the structure's improved ballistic behavior
remains uncompromised even in the very challenging circumstances of
water immersion which can, if not carefully prevented from
introducing any moisture into the cushioning core material,
appreciably disable the shock-handling capabilities of that
material.
[0006] Other features of the invention successfully improve the
state of the art with respect (a) to minimizing the build-up of
heat, (b) to maximizing the dispelling of perspiration, and (c) to
enhancing the action of evaporative cooling.
[0007] According to one very useful embodiment of the invention,
our proposed new structure includes (a) an outer body-contacting
layer which is formed of a suitable moisture-wicking material, (b)
an anatomically conforming, acceleration-rate-sensitive (preferably
viscoelastic), cushion-like structure, or layer, which is disposed
closely adjacent the moisture-wicking layer, and (c) a
continuous-surface, fully moisture-blocking, yet gas-permeable,
barrier layer forming a complete jacketing enclosure, or container,
around the viscoelastic layer. The cushion-like rate-sensitive core
layer structure can be, selectively, either of a single-component
or of a plural-component (plural sublayers) nature, and in the
setting of a military helmet, preferably takes the form of two,
individual, viscoelastic sublayers which have two different
durometers. In this helmet setting, and during use by a wearer, the
lower-durometer sublayer is employed closer to the head, and the
higher-durometer sublayer is on the opposite side of the
lower-durometer sublayer relative to the head, and is interposed
the lower-durometer sublayer and the outer external structure which
is still on the inside of a helmet. Within, and throughout the
full, three-dimensional boundaries of each rate-sensitive,
viscoelastic layer, the layer material therein is unfettered in its
uniform, omnidirectional performance in response to introduced
impact/shock loads. No other structure extends as a
non-"homogeneous" anomaly through and in this region, which other
structure would alter such uniform, all-over, load-response
behavior.
[0008] In this newly proposed layered structure, the
body-contacting (head-contacting in the case of a helmet)
moisture-wicking layer effectively draws moisture away from the
body. It accomplishes this, in the helmet environment, in a way
which is experienced as being superior to the related activity of a
conventional helmet support system. The barrier layer forms an
uninterrupted continuum enclosing the inside rate-sensitive core
material, and thus defines an absolute, limiting boundary for the
migration of wicked moisture, preventing it from wetting the
rate-sensitive material, and encouraging, at its outer surface,
rapid evaporation and attendant cooling. In addition, and as will
become apparent, the gas-permeable characteristic of this barrier
layer accommodates substantially uncompromised cushioning behavior
in the adjacent rate-sensitive, viscoelastic structure.
[0009] The cushioning, rate-sensitive, viscoelastic layer structure
(two sublayers in the preferred helmet embodiment described herein)
furnishes a unique and very effective response both to static and
to dynamic (shock/impactlballistic) loads. This material is
temperature and pressure sensitive, and tends to creep (flow
laterally) away from hot spots and from localized high-pressure
spots. It thus tends to evenize the distributed static (wearing)
load, and thus to eliminate, substantially, localized capillary
circulation loss, and hence, localized ischemia regions. This
latter-mentioned feature can be especially significant also in
tight bandaging situations.
[0010] Additionally, and very significantly with regard to shock
protection, the cushioning layer in the structure of this invention
responds (rate-resistantly) to shock-produced, rapid acceleration
with a resistance to deformation that generally rises in a somewhat
direct relationship to the level of acceleration. This kind of
acceleration-rate sensitivity is somewhat analogous to the
phenomenon known in the world of fluid mechanics as shear-resistant
fluid dilatancy. This behavior causes a shock load to be
transmitted to and borne by the body over a relatively wide surface
area, and thus generally reduces the likelihood of serious injury.
The rate-sensitive core material proposed by the structure of this
invention also responds to (and following) an impact event by
recovering slowly to an undeformed condition--thus avoiding any
dangerous "rebound" activity. The important and special
rate-resistant , and slow "recovery", response of this material
requires the maintenance of adequate gas-breathability (inflow and
outflow) during onset and recovery from deformation, in an
environment which also simultaneously guards the material against
the infusion of water, or other "solid-like" moisture. Moisture
infusion would dramatically and negatively affect
ballistic-response cushioning behavior.
[0011] The layer structure of this invention is easily rendered in
a variety of specific configurations, and thus is readily usable in
a host of different settings. It is relatively easy and inexpensive
to manufacture, and it can be introduced very conveniently in a
wide range of "retrofit" situations. The specific layer
organization of the invention which is chosen for different
selected applications is itself an accommodating variable--a
variable which enhances the invention's versatility. For example:
overall structure thickness can be different for different
circumstances. A single, or more than two, rate-sensitive
sublayer(s) can be employed. Within a relatively wide range, a
different specific durometer value (or values) for the
rate-sensitive sublayer(s) can be chosen. The moisture-wicking
layer can be distributed in different ways in the structure to suit
different use environments, and can be omitted if desired for use
of the invention in certain applications. The moisture-blocking
gas-permeable barrier layer can have different selected thicknesses
to suit different applications. Importantly, this layer is chosen
to be such, that in any situation, such as a water-immersion event,
which exposes the proposed new layer structure to significant
wetting, no water can penetrate the barrier layer to degrade the
shock-managing performance of the rate-sensitive layer material
encapsulated inside.
[0012] Another application of this invention involves the issue of
tight bandaging mentioned above. Such bandaging can significantly
reduce needed blood flow in the region of a wound, and a bandaging
interface structure built in accordance with the invention can
address this problem because of the presence of the
acceleration-rate sensitive material which tends to minimize
blood-vessel occlusion. An interface structure especially useful
for this application can take the form of a layered structure
wherein just one side of the employed acceleration-rate-sensitive
material can be guarded over its full effective surface area by a
moisture-blocking, but gas-permeable, barrier layer. The
moisture-wicking layer can be omitted if desired.
[0013] Accordingly, variations from, and modifications of, the
invention are recognized to be possible. Several of these are
mentioned specifically below.
[0014] All of the special features and advantages mentioned above
that are offered by the present invention will become more fully
apparent as the description which now follows is read in
conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a front elevation (with certain portions broken
away to reveal details of internal construction) of a military
helmet which is equipped with plural pad-like expanses (seven in
total number) of layered cushioning interface structure constructed
in accordance with one preferred embodiment of the present
invention.
[0016] FIG. 2 is a side elevation (also with portions broken away
to reveal internal construction) of the helmet of FIG. 1, on about
the same scale as and taken generally from the right side of FIG.
1, and tilted slightly toward the viewer.
[0017] FIG. 3 is an enlarged-scale fragmentary detail taken
generally in the area of curved arrows 3-3 in FIG. 2, showing in
cross section one of the interface structures employed in the
helmet of FIGS. 1 and 2.
[0018] FIG. 4 is a fragmentary cross-sectional detail which is very
much like the view presented in FIG. 3, showing one modified form
of the structure of the present invention.
[0019] FIG. 5 is a view which is very much like those presented in
FIGS. 3 and 4, showing yet another modified form of the
invention.
[0020] FIGS. 6A and 6B show two more embodiments of the invention
which are especially useful in wound bandaging applications.
DETAILED DESCRIPTION OF, AND BEST MODE FOR CARRYING OUT, THE
INVENTION
[0021] Turning attention now to FIGS. 1, 2 and 3, indicated
generally at 10 (FIGS. 1 and 2) is a military helmet including a
shell 10a. In all respects, shell 10a is completely conventional in
construction, and might have any one of a number of different
specific constructions and configurations. Fastened in a manner
that will shortly be described on the inside, concave, dome-like
wall of shell 10a is an installation 12 of body-contacting
interface structure constructed in accordance with the present
invention. Installation 12, in the particular setting illustrated
in these figures and now being described, includes seven,
individual, multi-layer, cushioning, interface-structure pads 12a,
12b, 12c, 12d, 12e, 12f, 12g, each of which is constructed with one
preferred form of a layered-assembly organization proposed by the
present invention. Each such pad is also referred to herein as a
body-contacting, expanse-like cushioning structure. Pad 12a is
joined to the inside wall of shell 10a in the frontal, central
portion of that wall, pads 12b, 12c on laterally opposite sides of
pad 12a, pads 12d, 12e in laterally spaced locations on the inside,
lower, rear portion of the inside wall of shell 10a, pad 12f
centrally between pads 12d, 12e, and pad 12g on the upper (or
crown) portion of the inside wall of shell 10a.
[0022] The perimetral shapes and the locations of these six pads,
and indeed the specific number of pads chosen for use in helmet 10,
are completely matters of choice, and form no part of the present
invention. These specific shapes, locations, and this number, have
been chosen in relation to equipping helmet 10 with an appropriate
body-contacting interface structure that acts between a wearer's
head and shell 10a. A description of pad 12a which now follows,
with regard to the layered construction (or assembly) of the pad,
fully describes the construction of each of the other six pads in
installation 12. It is useful to lead into this discussion by first
explaining generally the different orientations of pad 12a that
appear in FIGS. 2 and 3. Pad 12a, as shown in FIG. 2, has a
somewhat planar configuration, and appears to lie generally in a
plane 13 (shown in dash-dot lines) which slopes upwardly and to the
right in FIG. 2. In FIG. 3, plane 13 is rotated counterclockwise to
be vertical.
[0023] Accordingly, and focusing attention now on FIG. 3 along with
FIGS. 1 and 2, pad 12a includes a cushion-like structure, or layer,
16 made up of two cushion-like sublayers 16a, 16b, a
moisture-blocking, gas-permeable barrier layer 18, and a
moisture-wicking outer layer 20. In the specific construction now
being described, structure 16 effectively takes the form of a core
structure, and is so also referred to in the context of describing
and talking about the pads in installation 12. Layer 18 fully
envelops core structure 16, and similarly, layer 20 fully envelops
the combination of core structure 16 and layer 18. The assembly
including structure, or core structure, 16 and layers 18, 20 is
referred to herein as a layered assembly. The right side of pad 12a
in FIG. 3 is referred to herein as the body-facing side, and the
left side of the pad in this figure as the load-facing side. The
right side of core structure 16 is also referred to herein as its
body-facing expanse, and the left side of this core structure as
its load-facing expanse.
[0024] Each of the two sublayers (16a, 16b) which make up core
structure 16 is formed of a suitable acceleration-rate-sensitive
material, such as a viscoelastic urethane material, which
possesses, in technical terms known to those skilled in art, (a)
acceleration-rate sensitivity, (b) temperature sensitivity and (c)
pressure sensitivity. With regard to acceleration-rate sensitivity,
the materials in sublayers 16a, 16b respond to compressive
accelerations each with a resistance behavior that is likenable
generally to the sheer-resistance behavior which is observed in
certain fluids as a phenomenon known as fluid dilatancy. When
compressive pressure is applied to these viscoelastic materials, if
that pressure application is done at a very low acceleration rate,
the materials respond very readily and fairly instantaneously with
a yielding response. However, if such a pressure is applied
rapidly, i.e., with a rapid acceleration rate, the materials tend
to act very much like solids, and they do not respond rapidly with
a yielding action. Generally speaking, is the higher the rate of
acceleration associated with an applied compressing force, the more
like a solid material do sublayers 16a, 16b perform. An important
consequence of this acceleration response characteristic is that
the structure of the invention offers, in relation to prior art
structures, a superior shock-cushioning action. It thus offers a
significant improvement in injury avoidance. A contributing factor
also in this regard is that the materials in sublayers 16a, 16b,
after undergoing a compressive deformation, return relatively
slowly toward their pre-deformation configurations.
[0025] While there are, and may be, various appropriate
rate-sensitive materials that are employable, the description which
follows herein is written in terms of viscoelastic material which
performs very admirably.
[0026] The preferred two-sublayer make-up for core structure 16 is
further characterized by the fact that the rate-sensitive,
viscoelastic material in sublayer 16a has a lower durometer and
Indentation Load Deflection (ILD) response number than does the
material in sublayer 16b. Specifically, and in the construction now
being described, sublayer 16a has a durometer with an ILD number
(or rating) preferably in the range of about 15 to about 28, and
sublayer 16b a durometer with an ILD rating preferably in the range
of about 42 to about 55. Sublayer 16a herein is made of a
viscoelastic material designated as Confor CF-40, made by a company
called EAR Specialty Composites in Indianapolis, Ind. Sublayer 16b
is made of a viscoelastic material designated as Confor CF-45, also
made by this same company.
[0027] The overall thickness of core structure 16, i.e. the
dimension thereof measured laterally (or from left to right sides)
in FIG. 3 (shown at T.sub.1), is about 7/8-inches. Sublayer 16a has
a thickness pictured in FIG. 3 at T.sub.2 (measured in the same
fashion) of about 3/8 inches, and sublayer 16b, a thickness
pictured in FIG. 3 at T.sub.3 of about 1/2-inches. Sublayers 16a,
16b are joined to one another by means of a suitable adhesive
material.
[0028] Within the context of a two-sublayer make-up for core
structure 16, and with respect to an overall core structure
thickness which is greater than about 1/2-inches, it is preferable
that the thickness of sublayer 16a be maintained at no less than
about 3/8 inches. Where the overall thickness of core structure 16
is reduced to about 1/2-inches or less, it is preferable here that
this core structure be made of but a single layer of "lower
durometer type" viscoelastic material.
[0029] Under all circumstances, it is preferable, where a
multi-sublayer structure is employed for core structure 16, that
the component thereof which is toward the body-facing side of the
whole assembly have the lowest (in the case of more than two
layers) durometer number associated with it.
[0030] Another consideration regarding the structure of core
structure 16 is that, preferably, it have a quite uniform thickness
throughout. Uniformity of thickness plays an important role in
maximizing the capability of this core structure to conform as
precisely as possible with, in the case of a helmet, the topography
of the wearer's head. Our practice has been to create such a core
structure with an overall thickness which lies within a tolerance
range of about .+-.0.002-inches. This is the thickness tolerance
which characterizes the core structure pictured in helmet 10.
[0031] Within the three-dimensional body of each of the two
viscoelastic sublayers, there is no other structure present, save
ambient and entrained gas. Accordingly, each such body responds
substantially uniformly, and omnidirectionally, throughout its
entirety.
[0032] Barrier layer 18 which completely surrounds, encapsulates
and envelops core structure 16 in pad 12a is a sprayed-on layer
formed of a vinyl-solvent-based material known as Russell Coating,
and sold under the product designator V-2000 to identify this
product. It is made by Russell Products Company, Inc. at 275 N.
Forge Street, Akron, Ohio 44304. In general terms, this coating
product forms a smooth abrasion-resistant skin-like protective
layer over the outside surfaces of core structure 16. It provides a
breathable and durable membrane skin on the outside of the core
structure which completely blocks penetration of moisture into the
core structure, yet permits relatively free bidirectional gas flow
into and out of the core structure. Thus, it permits "breathing" of
core structure 16 under circumstances of compression and
return-from-compression. Preferably, this barrier layer has a
thickness somewhere in the range of about 0.007-inches to about
0.01-inches, and in the specific construction now being described,
has a thickness of about 0.009-inches. In the specific setting of
the military helmet now being described for illustration purposes,
full "jacketing" of the core cushioning structure by the barrier
layer enables the helmet be fully immersible in water without
experiencing any degradation in cushioning-material performance,
which degradation would result from any moisture entrance into the
rate-sensitive core material.
[0033] Jacketing the outside of the combined assembly of core
structure 16 and barrier layer 18 is moisture-wicking layer 20.
This layer, which can be treated as optional in certain
applications, is distributed somewhat in the form of an enclosure
bag around the core structure and barrier layer. In the
construction now being described, layer 20 takes the form of a
polyester fabric (with a nominal thickness of about 0.015-inches)
known as Orthowick, made by Velcro Laminates, Inc., 54835 C. R. 19,
Bristol, Ind. 46507. Specifically, this Orthowick material bears
the following product designator: VELCRO.RTM. brand Loop 3993. The
bag form of layer 20 is closed as by stitching generally where
appropriate, and such stitching exists, for example, in the area
shown at 22 in FIG. 3. As can be seen, this stitching does not
penetrate the barrier layer.
[0034] Pad 12a is anchored to the inside of helmet shell 10a
through a two-component conventional hook-and-pile structure 24
typically sold under the name Velcro--a readily commercially
available product made by Velcro USA, Inc., 406 Brown Avenue,
Manchester, N.H. 03108-4806. One component of this hook-and-pile
structure is suitably joined as by stitching or adhesive bonding to
the outside surface of layer 20 which is the surface that is on
what was referred to earlier as the load-facing side of pad 12a.
The other component of the hook-and-pile structure is suitably
joined to the surface (at the appropriate location) of the inside
wall in helmet shell 10a.
[0035] Turning attention now for a moment to FIG. 4, here there is
indicated, also designated 12a, a modified form of a pad usable in
helmet 10 at the location of previously described pad 12a. In this
FIG. 4 pad 12a, substantially all components therein are just as
described in pad 12a as pictured in FIG. 3, except that the
moisture-wicking layer 20 here takes one optional, modified form,
essentially, of a single expanse of material 20a which extends only
on and across what has been referred to previously as the
body-facing side of pad 12a. Completing with expanse 12a an
enclosure generally in a bag form around the assembly of core
structure 16 and barrier layer 18 is another expanse of material
26. Material 26 has a direct compatibility with one of the two
conventional components found in available hook-and-pile fastening
structure, such as previously-described structure 24. For example,
this material (26) might typically have compatibility with the
so-called "hook portion" of a hook-and-pile fastener material. In
FIG. 4, such a "hook portion" is shown at 28 suitably secured to
the inside wall of helmet shell 10a. An appropriate fabric which is
suitable for material expanse 26 is a material sold as Veltex
another readily commercially available product made by Velcro USA,
Inc. The Veltex product specifically employed in pad 12a herein
bears the product designator: VELCRO.RTM. brand Loop 3981.
[0036] FIG. 5 in the drawings illustrates yet another modified form
of a pad 12a made in accordance with the invention. This FIG. 5 pad
12a differs from pad 12a as shown in FIG. 3 by the fact that core
structure 16 here includes but a single,
acceleration-rate-sensitive, viscoelastic component, or sublayer
element, shown at 16c. Component 16c has a thickness, indicated at
T.sub.4 in FIG. 5, of about 1/2-inches, and is formed generally of
the same kind of viscoelastic material described earlier as having
a durometer rating with an ILD number in the range of about 15 to
about 28. Thus, component 16c herein is made of the EAR Specialty
Composites material designated as Confor CF-40.
[0037] A factor to note now in relation to the several structural
embodiments that have been illustrated and described so far with
regard to the present invention is that, fundamentally, the
features of the invention which offer the advantages ascribed to it
are furnished by the presence of certain cooperating layers of
material. These layers, in a preferred form of the invention,
include a moisture-wicking body-contacting layer, a
moisture-blocking, gas-permeable barrier layer, and a cushioning
layer which is formed preferably of a rate-sensitive material, such
as a viscoelastic material, that offers the qualities of
temperature sensitivity, pressure sensitivity and acceleration-rate
sensitivity described above for structure 16. And, while such a
three-layer organization is generally preferred, and as was
mentioned above, the moisture-wicking layer can be omitted in
certain applications.
[0038] FIGS. 6A, 6B show two further modifications of the present
invention. Each includes a single layer 16 of viseoelastic
material, and each also includes but a single-side coating of
barrier-layer material on the viseoelastic layer. The modification
shown in FIG. 6A further includes a moisture-wicking layer 20,
whereas the FIG. 6B modification does not posses such a layer. One
should recall statement herein regarding an earlier certain
applications wherein moisture wicking is not a needed function.
[0039] Both of these FIGS. 6A, 6B modifications of the invention
are useful in the field of wound dressing, for example as a
protective covering wrapped or taped over a wound. In such an
application, the viseolastic layer 16 responds to blood-flow
activity by shaping itself so as not to occlude such flow, while
nonetheless maintaining desired pressure on surrounding regions. As
a wound dressing therefore, the invention tends to promote more
rapid healing.
[0040] In the wound dressing environment, moisture barriering and
gas breathability, as provided by layer 18, need only be one-sided
since problematic moisture attack will typically only come from the
single "wound" side of a dressing.
[0041] Thus, there is provided by the present invention a unique,
layered, body-contacting, cushioning structure which offers the
various benefits ascribed to it hereinabove--which benefits offer
significant improvements over related prior art structures. When
the structure of the present invention engages the human body, such
as the head of a wearer of a helmet like that shown and described
with respect to FIGS. 1-5, inclusive, initial contact areas with
the head which may define raised or elevated pressure points are
reacted to by behavior in core structure 16 in a manner which
causes these pressure points to disappear, and to yield to a
relatively even overall contact pressure regarding the head. For
example, such a pressure point is generally shown in FIG. 1 by the
cross which is designated P, a pressure point which can be thought
of as acting along a line of action shown by the dash-dot line
shown at P in FIG. 2, and by the arrow P in FIG. 3.
[0042] Such an initial pressure point might also be characterized
as a warm spot that has a somewhat elevated regional temperature
because of close, higher-pressure contact with the skin of the
head, for example. This condition, along with the elevated local
pressure condition just mentioned, will cause core structure 16 to
begin to adjust by lateral flow or creep, somewhat as is
illustrated by the three curved dashed lines present in FIG. 3.
This effectively causes the structure of the invention to retreat
from exerting localized elevated-pressure contact with the head,
thus to eliminate a differentiating high-pressure point, and
accordingly to conform to head topography in a way that avoids
capillary circulation-loss discomfort. This specific behavior is
exactly shat makes the structure of the invention so useful in the
settings of wound dressings.
[0043] Evenizing and "delocalizing" of static contact pressure
because of the kind of action just described reduces substantially
to non-existence the likelihood of a wearer of a helmet, like
helmet 10, experiencing the kind of pain and discomfort described
earlier herein. Contact of the head directly with a
moisture-wicking layer, such as layer 20, is effective preferably
to rid perspiration readily and quickly from the head, and in the
process, to promote enhanced evaporative cooling. The presence of
barrier layer 18 assures that wicked-away and ridden moisture, as
well as any water-immersion moisture, does not enter the
rate-sensitive, viscoelastic cushioning material(s) to interfere
with the cushioning performance of structure 16.
[0044] Beyond the somewhat static conditions just described which
make the wearing of a helmet like helmet 10 far more comfortable
than the wearing of a conventional helmet (with a conventional head
support structure), if and when a shock load is transmitted through
the helmet to the head of the wearer, the rate-sensitive nature of
structure 16 causes that structure to respond with the behavior
described earlier herein to act in an acceleration-resistant
fashion that causes such a shock load to be distributed over a very
broad expanse, rather than over a very small localized region of
the head. This behavior causes the structure of the present
invention, therefore, to offer superior ballistic response
capabilities in relation to the likelihood of a serious injury
occurring for a given kind of impact or shock-load event.
[0045] While the invention has been disclosed in particular
settings, and in particular forms herein, the specific embodiments
disclosed, illustrated and described herein are not to be
considered in a limiting sense. Numerous variations, some of which
have been discussed, are possible. Applicants regard the subject
matter of their invention to include all novel and non-obvious
combinations and subcombinations of the various elements, features,
functions and/or properties disclosed herein.
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