Note: Descriptions are shown in the official language in which they were submitted.
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GEL FILLED TRAUMA MITIGATION
DEVICE AND COMPOSITION THEREFORE
CROSS REFERENCE TO RELATED APPLICATIONS
This Application claims the benefit of U.S. Provisional Application Serial No.
60/223,633 filed August 8, 2000.
FIELD OF THE INVENTION
This invention provides laminar devices for mitigating trauma to humans and
other members of the animal kingdom, that would occur upon impact as a result
of
automobile collisions, boating accidents, and the like.
BACKGROUND
When an occupied vehicle is involved in a collision, forces are transmitted
through the materials of the vehicle to the occupants of the vehicle; another
concomitant accident generally occurs, often referred to as the second
collision,
which subjects the occupants to impacts with the inside surfaces of the
vehicle. For
example, in some automobile collisions, it has been measured that 6
kilonewtons of
force are imposed on the tibia of an occupant, resulting in compound
fractures. As
another example, in racing boats and on the seats of log skitters, damaging
forces
may be transmitted through the construct of the vehicle and to the anatomy of
occupants. The present invention is designed to eliminate or mitigate
traumatic
injuries due to such impacts.
SUMMARY
The present invention provides a device that helps to dissipate the energy of
the impact rather than allowing it to be transmitted directly to the protected
subjects
(e.g. occupants of a vehicle). The trauma-mitigating effects are provided by a
laminar
(flat layered) device of the present invention, sometimes referred to herein
for short as
a "laminate." Devices of the present invention may be produced in various
thicknesses, preferably 9 cm and less. The elements of the laminar device have
cumulative effects in protecting the subjects when an impact occurs. The
laminate is
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intended to minimize damaging forces which may be transmitted to the lower
limbs
and other body parts. Included in this invention are several embodiments
designed to
protect occupants in a vehicle from injury to limbs and body surfaces due to
the
"second collision" and/or transmission of force through the structural
elements of the
vehicle. The invention helps to reduce impact forces, and resulting injury, by
providing a multilayered device between a source of impact and the protected
subject,
e.g. a vehicle and its occupants.
When a vehicle is in motion, it moves at an essentially steady speed along
with the human occupants. A collision causes the vehicle to undergo a rapid
deceleration. The occupants continue to move at the same steady pace as the
vehicle
did initially. When the occupants come into contact with the decelerating
vehicle,
portions of the anatomy experience the force produced by the difference in
deceleration of the human body and the vehicle. A device of the present
invention
reduces the impact on any one portion of the anatomy that would otherwise be
produced by this deceleration difference, thus resulting in reduced force and
reduced
inj ury.
The space or distance between the interior of a vehicle and the occupant is
limited. Therefore, an intervening laminate must effect a reduction in
relative speed
between the two over a short distance. The shorter the distance and the
shorter the
time, the greater the energy generated. One function of the laminate is to
undergo
deformation, converting to heat the energy generated. A second function of the
laminate is to minimize the force conveyed to the subject's anatomy by
spreading it
over as wide an area as possible. This results in a large reduction in trauma
and
concomitant injury to a part of the anatomy which might be impacted.
The laminate of the current invention efficiently provides the aforesaid
functions. Some layers in the laminate compress and defornl when forces are
applied.
Other layers respond at the point of contact to distribute the force over an
area of the
device. Internal to one of the layers, elements within a viscous fluid
interact to
dissipate forces.
In certain embodiments, the laminate is located on and integral to the
footwell
or toepan surface. It could also be used on the knee bolster to protect the
driver and
front seat passenger.
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In its most general form, the laminate of the present invention comprises an
enclosed crushable structure adapted to deform in a predetermined manner upon
sudden impact. The enclosed crushable structure comprises a fluid-impervious
flexible enclosure containing a crushable matrix bathed in a highly viscous
fluid
composition.
The crushable matrix desirably comprises a multiplicity of matrix elements
arrayed within and each disposed generally perpendicular to the principal
plane of the
laminate. These matrix elements may, for example, be cylindrical,
hemispherical or
pyramidal, or a mixture thereof. Preferably some or all of the matrix elements
are
formed of a pair of hemispheres or pyramids secured together at a convexity or
an
apex. Optionally, some or all of the matrix elements are provided with a
multiplicity
of crushable arms extending therefrom. Optionally, the hemispherical or
pyramidal
elements may be used in combination with cylindrical elements.
Optionally the enclosed crushable structure includes a thin supporting layer
above and/or below the multiplicity of matrix elements. Such a supporting
layer may
be a ductile metal such as aluminum or copper, in a corrugated or other
crushable
shape, or it may be cast or otherwise fashioned as a corrugated, honeycomb or
similar
shape of polymeric material, having a rubbery or solid consistency, or it may
be
entirely or partly of ceramic or ceramic alloy.
Alternatively, such a thin supporting layer may be sandwiched outside the
enclosed crushable structure.
The fluid-impervious flexible enclosure that encloses the enclosed crushable
structure may be of polymeric film or of rubberized or elastomeric woven or
nonwoven fabric of suitable toughness to withstand expected forces without
rupturing. It s preferably formed of a pair of parallel 20-mil-thick
rubberized, fluid-
impervious barners. These barriers may optionally be formed of a single sheet
folded
over itself. They may be joined together by a somewhat thinner film (e.g. 10
to 15
mil) along some or all of the periphery. One or more edges of the enclosure
preferably have one or more accordion pleats (gussets) to accommodate
percussive
expansion along the plane of the laminate.
The highly viscous fluid composition is enclosed in the fluid-impervious
flexible enclosure. It comprises a viscous fluid having a viscosity from about
300,000
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CPS to about 6 million CPS (i.e. semi-solid, such as a gel or bloclc polymer).
When
there is an impact on a device of the present invention, the crushable matrix
interacts
with the viscous fluid to transfer energy thereto or therein, generating
movement of
the elements within the viscous fluid and movement along the plane of the
laminate
and also dissipating energy in the form of heat.
Preferably the highly viscous fluid also comprises low-density microsphere
particulates, having a diameter of about 100 to 400 microns. Such microsphere
particulates may be ceramic or plastic, or a mixture of both may be used.
More preferably, the highly viscous fluid comprises macrosphere particulates,
e.g. a foamed polymer such as polystyrene, having a diameter of about 0.5 mm
to 5
mm, either alone or in combination with microspheres. Desirably, particulates
of
various sizes comprise 20% to 40% of the highly viscous fluid by volume. When
there is an impact on a device of the present invention, the crushable matrix
interacts
with the particulate components of the viscous fluid to transfer energy
thereto.
The fluid-impervious flexible enclosure may comprise a polymer film of
suitable thicl~ness and toughness to maintain its integrity through the
expected
impacts, or it may be made of two or more plies comprising fabric or
elastomer. One
such ply may be of polynorbornene or butyl rubber, to provide softness and
additional
resiliency. Major portions of the enclosure may optionally be made by
coextrusion,
e.g. of polymer film and metallic film.
For adherence to metal, e.g. the floor of a vehicle or a thin crushable layer
of
ductile metal as described hereinabove, a metal-adhering film such as
XU661126.02
(Dow Chemical Co., Midland, MI) may be employed.
In another aspect of the invention, the enclosed crushable structure is
surmounted by a layer of fully reticulated foam. A source of pressurized air
is
provided so that when an impact (sudden deceleration or acceleration) is
sensed, the
foam layer is pressurized.
In an embodiment used as an example herein, a laminate of the present
invention is composed of the following layers. The uppermost layer is the
carpet
provided as automotive floor covering. The next layer is of reticulated foam.
Then
comes the enclosed crushable structure, starting with a film that forms the
top of the
fluid-impervious flexible enclosure. The thin supporting layer within the
flexible
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enclosure is a honeycomb or corrugated structure designed to collapse upon
impact.
A matrix comprising a plurality of matrix elements is immediately outside the
thin
supporting layer. It is bathed in a highly viscous fluid composition, which
includes
microspheres and macrospheres. A corrugated aluminum thin supporting layer is
next
outside. The bottom of the flexible enclosure is next, and optionally an
adhesive film
is provided which attaches to the vehicle structure.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagrammatic, cross-sectional exploded view of an embodiment
of the present invention wherein the matrix elements are cylindrical.
Figure 2 is a plan view of the embodiment of Fig. 1, tal~en along line 2-2.
Figure 3 is a view similar to Fig. 1, of an alternative embodiment wherein the
matrix elements comprise joined hemispherical sections.
Figure 4 is a view similar to Fig. 1, of an alternative embodiment wherein the
matrix elements comprise joined pyramids.
Figure 5 is a view similar to Fig. 1, but of only the matrix of yet another
alternative embodiment.
Figure 6 is a diagrammatic cross-sectional view of yet another alternative
embodiment.
Figure 7 is a diagrammatic cross-sectional view of still another embodiment.
DETAILED DESCRIPTION
The present invention will be described in greater detail in conjunction with
the appended drawings.
Fig. 1 shows an example of the laminar trauma-mitigation device 100 of the
present invention as may be applied to the footwell or toepan 110 of an
automobile.
For easier viewing, some of the layers that are actually contiguous are shown
slightly
separated, in this somewhat exploded view.
The carpet layer 101 is commonly used floor covering in automobiles, either
woven or pile carpeting. It is decorative as well as functional, as it may be
color-
coordinated with the rest of the vehicle, and it is the layer in direct
contact with the
protected occupants of the vehicle.
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An upper cushion layer 102 is desirably provided below the carpet layer 101.
It is of soft, resilient material such as butyl rubber, polynorbornene,
polyvinyl
chloride or polyurethane.
A foam layer 103 is desirably provided next below. This layer may be of
polyurethane or other inflatable fully-reticulated foam and is provided with
an
inflation tube 130 through which external air pressure may be provided to
expand it
and provide additional resiliency. Desirably pressurized air is directed into
foam
layer 103 through the inflation tube 130 when an impact is sensed and the
vehicle's
air bags are deployed. In certain embodiments of the present invention, the
foam
layer 103 may be omitted.
Optionally a lower cushion layer 122 may be provided immediately below
the foam layer 103.
An upper enclosure layer 104 is provided below the foam layer 103 (and
below a lower cushion layer 122 if such is included). The upper cushion layer
102
and upper enclosure layer 104 desirably serve to seal the upper and lower
surfaces
of foam layer 103 to make it generally airtight and susceptible to inflation
through
inflation tube 130. Alternatively, the surfaces of foam layer 103 may be
sealed by a
thin polymeric film or other means.
The fluid-impervious flexible enclosure 120 that encloses the enclosed
crushable structure 150 may be of polymeric film or of rubberized or
elastomeric
woven or nonwoven fabric of suitable toughness to withstand expected forces
without rupturing. It is preferably formed of a pair of parallel 20-mil-thick
rubberized, fluid-impervious barriers 104 'and 108. The barriers 104, 108 are
joined together by a somewhat thinner film 116, having accordion pleats
forming
gussets to accommodate percussive expansion along the plane of the laminate.
A thin supporting honeycomb metallic layer 105 comprises an upper portion
of the crushable structure 150. It provides excellent behavior by collapsing
under
pressure and absorbs energy by so doing. In an alternative embodiment, a layer
of
corrugated sheet aluminum or other similar material may be substituted.
Within the flexible enclosure 120 is a highly viscous fluid 160 which bathes
the contents thereof. It comprises a viscous fluid having a viscosity from
about
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300,000 CPS to about 6 million CPS (i.e. semisolid, such as a gel or block
polymer). When there is an impact on a device of the present invention 100,
the
crushable matrix 106 interacts with the viscous fluid 160 to transfer energy
thereto
or therein, generating movement of the elements within the viscous fluid and
movement along the plane of the laminate and also dissipating energy in the
form of
heat.
Preferably the highly viscous fluid also comprises low-density microsphere
particulates 161, having a diameter of about 100 to 400 microns. Such
microsphere
particulates 161 may be ceramic or plastic, or a mixture of both may be used.
More preferably, the highly viscous fluid also comprises macrosphere
particulates 162, e.g. a foamed polymer such as polystyrene, having a diameter
of
about 0.5 mm to 5 mm. Desirably, particulates of various sizes comprise 20 %
to
40 % of the highly viscous fluid 160 by volume.
The mid section of the crushable structure 150 is a crushable matrix 106
formed from a plurality of vertically-oriented cylindrical elements 166. Fig.
2 is a
plan view of the crushable matrix 106 showing the cylindrical elements 166
arrayed
as in a grid. Any of various layouts for the crushable elements may be
employed in
accordance with the present invention, the important point being that the
elements
be bathed in the highly viscous fluid 160. Optionally some or all of the
elements
may be filled with air (as shown in Figs. 1 and 2) or may alternatively
contain
highly viscous fluid 160.
The lower portion of the crushable structure 150 is formed by a thin
supporting honeycomb metallic layer 107. In an alternative embodiment, a layer
of
corrugated sheet aluminum or other similar material may be substituted.
Below the honeycomb metallic layer 107 is the fluid-impervious barrier 108
mentioned above. This constitutes the bottom of the flexible enclosure 120.
A metal-adhering film 109 such as XU661126.02 (Dow Chemical Co.,
Midland, MI) may be employed to secure the flexible enclosure 120 to the
toepan
110 or other metallic structure in a vehicle. It is a high quality adhesive
tape which
serves to attach the laminate structure to a metal surface in the automobile
where the
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environment of large swings of temperature, and with lubricants present which
might interfere with adhesion. Optionally, the lower fluid-impervious barrier
108
may itself be formed of such film.
Fig. 3 shows an alternative embodiment of the trauma-mitigation device 300
of the present invention. A carpet 301 overlies an upper cushion layer 302. A
foam layer 303 is provided with an inflation tube 330 generally as described
above.
An upper enclosure layer 304 is provided below the foam layer 303, forming
the top of the fluid-impervious flexible enclosure 320. Flexible enclosure 320
encloses the crushable structure 350. The structure 350 comprises an upper
corrugated layer 305, a lower corrugated layer 307, and a crushable matrix
306.
The crushable matrix 306 comprises hemispherical elements 366 joined
together at respective convexities. The elements 366 are bathed in viscous
fluid
360. As shown for this embodiment, the viscous fluid 360 is within the volumes
circumscribed by the elements 366 as well as outside of them. Highly viscous
fluid
360 comprises a viscous fluid of soybean oil, linseed oil, sunflower oil, or
pine oil
(along with antioxidant or other customary preservative); an oil/water
emulsion; or
petroleum oil, silicone, block polymer or other benign viscous substance, as
well as
microparticles 361 and macroparticles 362 distributed therethrough.
The corrugated metallic layer 307 forms the lower portion of the crushable
structure 350, which also comprises the crushable matrix 306 and corrugated
metallic layer 305.
Fluid-impervious barrier 308 forms the bottom of the flexible enclosure 320,
which also comprises the barrier 304 and gusseted edges 316.
Adhesive layer 309 bonds the enclosure 320 to the toepan 310.
Fig. 4 shows an alternative embodiment of the device 400 of the present
invention. The crushable structure 350 comprises a pair of honeycomb
structures
405 and 407, as well as a multiplicity of pyramidal elements 466 that together
comprise a matrix 406. As shown the pyramidal elements are joined at their
apexes
470, and their bases 472 abut the honeycomb structures 405 and 407.
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The interiors of the pyramidal elements of this embodiment may be filled
with air, and the exteriors are bathed in highly viscous fluid 460.
Fig. 5 shows the matrix of an alternative embodiment, wherein the crushable
structure 550 consists of a multiplicity of pyramidal matrix elements 566.
This
embodiment does not contain a honeycomb or corrugated layer in the crushable
structure 550. In use, the honeycomb or corrugated layer may be entirely
omitted,
or such layers may be placed outside the flexible enclosure 520.
Fig. 6 shows an embodiment of the invention wherein the crushable structure
650 comprises a multiplicity of pyramidal matrix elements 666 which are
smaller
than the matrix elements 466 shown in Fig. 4. The elements 666 are attached to
corrugated layers 605 and 607 by arms 667 extending from the bases of the
pyramids. Each of the aforesaid elements is a part of the crushable structure
650
and is bathed in highly viscous fluid 660.
Similarly Fig. 7 shows an embodiment of the invention wherein the
crushable structure 750 comprises a multiplicity of pyramidal matrix elements
766
which are attached to honeycomb layers 705 and 707 by arms 767 extending from
the bases of the pyramids. Each of the aforesaid elements is a part of the
crushable
structure 750 and is bathed in highly viscous fluid 760.
Those of skill in the art will understand that the aforesaid embodiments are
examples of the more generalized invention described above in the Summary.
