Note: Descriptions are shown in the official language in which they were submitted.
SHOCK ABSORBERS FOR PROTECTIVE BODY GEAR
TECHNICAL FIELD
[0001] The present invention relates generally to shock absorbers for use
in protective structures
such as body gear, and more particularly to fluid-filled compressible cells.
BACKGROUND
[0002] During sports and other physical activity, individuals are often
exposed to impact forces
that, if not at least partially attenuated, can cause severe injury.
Therefore, they usually wear
protective sporting gear, such as helmets, shields, elbow and knee pads, etc.
Such protective gear
typically includes impact-attenuating structures that deform elastically
and/or plastically in response
to an impact force, thereby mechanically attenuating the impact. For example,
many helmets have a
crushable foam layer disposed between a rigid or semi-rigid outer shell and an
inner liner that
conforms the helmet to the wearer's head.
[0003] Foams are generally customized to respond optimally to a specific
range of impact
energies, but outside this range, their effectiveness is significantly
reduced. For impact energies
exceeding the high end of the range, the foam is too soft and "bottoms out" ¨
i.e., reaches maximum
compression ¨ before the impact is fully attenuated, resulting in the transfer
of high impact forces to
the body. For impact energies below the optimal range, on the other hand, the
foam is too hard to
compress, or "ride down," sufficiently to adequately prolong the distance and
time over which
deceleration occurs following impact, resulting in sudden, high peak forces.
The only way to
improve the impact-attenuating capability of a foam layer is, typically, to
decrease the density of the
foam (i.e., make it softer) and increase the thickness of the layer, which
results in an undesirable
increase in the amount of material used. Exacerbating this trade-off, the
maximum ride-down
distance for most foams is only about 30-40% of the original height. Thus,
about 60-70% of the
foam layer add to the bulk and weight, but not the impact-absorption capacity,
of the protective
structure. In addition, the performance of many foams degrades rapidly with
repeated impacts.
Other conventional impact-absorbing layers exhibit similar problems and
limitations.
[0004] More recent helmet designs feature, in place of a continuous layer,
discrete fluid-filled
compression cells, which resistively vent a fluid through an orifice of the
cell enclosure to
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=
attenuate the impact. These cells generally have ride-down distances close to
their height,
exhibit superior durability, and adapt to a wide range of impact energies.
Furthermore, they
provide opportunities for tailoring the impact-absorption characteristics of
the helmet (or other
protective structure) via the cell design. Such customization opportunities,
however, have rarely
been exploited.
SUMMARY
[0005] The present invention provides shock absorbers for integration into
protective
structures, such as, for example, helmets and other protective body gear, as
well as dashboards,
shock-absorbing seating, and safety padding in vehicles, sporting equipment,
and machinery.
The shock absorbers generally take the form of hollow, fluid-filled,
compressible cells. In
preferred embodiments, the cell enclosure includes one or more orifices, or
vents, through which
a fluid (such as air or water) can escape from the inner chamber formed by the
enclosure. Such
compression cells utilize, simultaneously or in sequence, two impact-
attenuating mechanisms:
resistance of the cell enclosure to compression, and resistive fluid-venting
through the orifice(s).
In some embodiments, the cell attenuates impact forces by resisting
compression at least initially
through both the enclosure (or walls) and the fluid. Following an initial
stage of the impact, the
walls may yield to allow the remainder of the impact to be attenuated via
resistive fluid-venting.
The enclosure may include features that increase resistance to compression as
the cell
approaches the fully compressed state. Various embodiments of the present
invention are
directed to improving the energy management characteristics of the shock
absorbers by tailoring
the structure and shape of the enclosure, and/or the size and shape of the
vents.
[0006] The compression cells may include top, bottom, and side walls, and
may (but need
not necessarily) be symmetrical around an axis through the center points of
the top and bottom
walls. For example, the cells may be disk-shaped or cylindrical. The side
walls may be, without
limitation, straight, angled, curved, or frustoconical, depending on the
impact absorption profile
desired for the particular application. In certain embodiments, two
frustoconical portions of the
side walls are arranged back-to-back such that the walls toe in toward a
medial plane,
accelerating the reduction of the inner volume as the cell collapses. The
exterior shape of the
cell may be adjusted to the protective structure in which it is integrated.
For example, shock
absorbers for use in helmets may have rounded (rather than planar) top walls
to better fit between
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the interior liner and the shell, and/or side walls that taper toward one side
to better
accommodate the narrow space along the periphery of the helmet.
[0007] The wall or walls of the shock absorber may be of uniform or varying
thickness,
depending on the desired shock absorption profile. For example, in some
embodiments, the side
walls increase in thickness from the top wall toward the bottom wall,
resulting in increased
resistance as the top wall approaches the bottom wall during compression. In
other
embodiments, the side walls decrease in thickness toward the bottom, which may
result in
shearing of the cell during the initial phase of the impact, followed by
compression. Further,
corrugations in and/or structures protruding from the top and/or bottom walls
may contact the
opposing wall during a late stage of compression. thereby effectively
increasing the number of
side walls that contribute to impact absorption.
[0008] In some embodiments, the enclosure includes features that alter the
rate of fluid-
venting through the orifice. For example, a pin at the bottom wall may engage
with (i.e.,
partially or totally plug) an orifice through the top wall so as to obstruct
the latter when the shock
absorber is compressed. Alternatively, the rim around the orifice may extend
into an open tube
that impedes fluid flow when it makes contact with the opposing wall. In
certain embodiments,
the orifice is equipped with a check valve or other structure that regulates
fluid flow. These and
similar features may be used individually or in various combinations to
customize the shock-
absorption characteristics of the compression cell.
[0009] Accordingly, in a first aspect, the invention relates to a
compressible cell for
attenuating impact forces imparted thereto. In various embodiments, the cell
comprises an
enclosure defining an inner chamber for containing a fluid; the enclosure
includes a side wall,
extending and varying in thickness between a top wall and a bottom wall, that
resistively yields
in response to an impact imparted to the top wall. The side wall may increase
or decrease in
thickness from the top to the bottom wall. The resistance of the yielding side
walls may increase
with increasing energy of the impact and/or increased compression of the side
wall. fhe cell
may shear in response to a non-perpendicular impact force. In various
embodiments, the cell
further comprises at least one orifice in the enclosure for resistively
venting fluid from the inner
chamber so as to at least partially attenuate the impact when the side wall
yields.
[0010] In another aspect, the invention relates to a method involving a
safety article that
comprises a compressible cell including an enclosure defining an inner chamber
and having a
3
side wall extending and increasing in thickness between a top wall and a
bottom wall, where the
safety article is worn on a body with the bottom wall closer to the body than
the top wall. The
method is directed toward protecting the body from damage due to impacts and
comprises, in various
embodiments, attenuating an impact imparted on the top wall at least partially
with the side wall by
resistively yielding, where resistance to yielding increases with increased
compression of the side
wall. In various embodiments, the enclosure has an orifice and the method
further comprises
attenuating the impact at least partially by venting fluid from the inner
chamber through the orifice.
[0011] In a further aspect, the invention relates to a method involving a
safety article that
comprises a compressible cell including an enclosure defining an inner chamber
and having a side
wall extending and decreasing in thickness between a top wall and a bottom
wall, where the safety
article is worn on a body with the bottom wall closer to the body than the top
wall. The method is
directed toward protecting the body from damage due to impacts and comprises,
in various
embodiments, attenuating a tangential component of an impact imparted on the
top wall at least
partially by shearing, and attenuating a normal component of the impact
imparted on the top wall at
least partially with the side wall by resistively yielding. In some
embodiments, the enclosure has an
orifice and the method further comprises attenuating the impact at least
partially by venting fluid
from the inner chamber through the orifice.
[0012] In another aspect, the invention pertains to a compressible cell for
attenuating impact
forces imparted thereto. In various embodiments, the cell comprises an an
enclosure defining an
inner chamber for containing a fluid, the enclosure comprising a non-
corrugated bottom wall, a top
wall including at least one corrugation defining a periphery around a central
portion of the top wall
and being spaced from the bottom wall, and a side wall extending between the
top and bottom walls,
the side wall and the at least one corrugation of the top wall resistively
yielding in response to an
impact imparted to the top wall so as to attenuate impact forces while
allowing the cell to compress,
the enclosure further comprising at least one orifice for resistively venting
fluid from the inner
chamber so as to at least partially attenuate the impact. The corrugations may
increase resistance to
compression of the cell as they contact the bottom wall. In various
embodiments, the top wall is
configured to allow lateral movement of a center region thereof relative to a
periphery thereof.
Furthermore, the side wall may vary in thickness between the top wall and the
bottom wall.
[0013] The cell may be configured for use between an exterior shell and an
interior liner of an
impact-attenuating helmet, in which case the top wall may be domed so as to
conform to the inner
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surface of the exterior shell. Moreover, the enclosure may be tapered at the
top wall so as to fit
between the shell and the liner in a peripheral region of the helmet.
[0014] In still a further aspect, the invention relates to a method
involving a safety article that
comprises a compressible cell including an enclosure defining an inner
chamber, a top wall having at
least one corrugation defining a periphery around a central portion of the top
wall, a non-corrugated
bottom wall, and a side wall extending between the top and bottom walls, the
safety article being
worn on a body with the bottom wall closer to the body than the top wall. The
method is directed
toward protecting the body from damage due to impacts, and comprises:
attenuating an impact
imparted on the top wall at least partially with the side wall by resistive
yielding thereof; and upon
contact of the corrugations with the bottom wall, attenuating the impact at
least partially with the side
wall and the corrugations of the top wall by resistive yielding thereof. In
some embodiments, the
enclosure has an orifice and the method further comprises attenuating the
impact at least partially by
venting fluid from the inner chamber through the orifice.
[0015] In yet another aspect, the invention pertains to a compressible cell
for attenuating impact
forces imparted thereto, and which, in various embodiments, comprises an
enclosure defining an
inner chamber for containing a fluid; the enclosure comprises at least one
side wall extending
between a top wall and a bottom wall, and the side wall(s) resistively yield
in response to an impact
imparted to the top wall so as to allow the cell to compress. The top wall
and/or the bottom wall
comprises vertically extending features that increase resistance to
compression of the cell as the top
wall approaches the bottom wall. In some embodiments, the cell further
comprises at least one
orifice in the enclosure for resistively venting fluid from the inner chamber
so as to at least partially
attenuate the impact. The features may comprise corrugations around a
periphery of the top wall
and/or a plurality of concentrically arranged ridges on the bottom wall. In
some embodiments, the
side wall varies in thickness between the top wall and the bottom wall. The
cell may be configured
for use between an exterior shell and an interior liner of an impact-
attenuating helmet, with the top
wall being domed so as to conform to the inner surface of the exterior shell.
The enclosure may be
tapered at the top wall so as to fit between the shell and the liner in a
peripheral region of the helmet.
[0016] In still a further aspect, the invention relates to a method
involving a safety article that
comprises a compressible cell including an enclosure defining an inner
chamber, a side wall, and
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top and bottom walls at least one of which includes vertically extending
features. The safety
article is worn on a body with the bottom wall closer to the body than the top
wall. The method
is directed toward protecting the body from damage due to impacts and in
various embodiments
comprises, in response to an impact imparted to the top wall, attenuating the
impact at least
partially with the side wall by resistive yielding thereof; and attenuating
the impact at least
partially with the vertically extending features as the top wall approaches
the bottom wall. The
enclosure may have an orifice, and the method may further comprise attenuating
the impact at
least partially by venting fluid from the inner chamber through the orifice.
[0017] In a further aspect, the invention pertains to a compressible cell
for attenuating impact
forces imparted thereto, and which, in various embodiments, comprises an
enclosure defining an
inner chamber for containing a fluid; the enclosure compresses in response to
an impact. The
cell also includes at least one orifice in the enclosure for resistively
venting fluid from the inner
chamber during the compression so as to at least partially attenuate the
impact, and a valve for
partially obstructing the orifice so as to increase resistance to the
compression. In various
embodiments the enclosure comprises top and bottom walls, and the resistance
to the
compression of the cell is increased by the partial obstruction of the orifice
as the top wall
approaches the bottom wall. Some or all of the walls may resistively yield in
response to the
impact, thereby partially attenuating the impact while allowing the cell to
compress. In various
embodiments, the valve comprises a pin protruding from the bottom wall
opposite the orifice,
where the pin, in a compressed state of the cell, engages the orifice so as
restrict fluid venting
therethrough. Alternatively, the valve may comprise a tubular protrusion
extending downward
from the top wall and surrounding the orifice. The tubular protrusion self-
restricts the orifice due
to increased fluid turbulence.
100181 Yet another aspect of the invention relates to a method involving a
safety article that
comprises a compressible cell that includes an enclosure defining an inner
chamber and having
an orifice and a valve therein. The method is directed toward protecting the
body from damage
due to impacts and comprises, in various embodiments, attenuating an impact
imparted on the
enclosure at least partially by resistively venting fluid from the inner
chamber through the
orifice, whereby the enclosure compresses, during compression of the
enclosure, increasing a
resistance to compression by partially and increasingly obstructing the
orifice with the valve.
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[0019] Still another aspect of the invention pertains to a compressible
cell for use between an
exterior shell and an interior liner of an impact-attenuating helmet. In
various embodiments, the
cell comprises an enclosure comprising a top wall, a bottom wall, and at least
one side wall that
resists yielding in response to an impact at least during an initial phase
thereof, the enclosure
defining an inner chamber for containing a fluid; and at least one orifice in
the enclosure for
resistively venting fluid from the inner chamber so as to at least partially
attenuate the impact
after the initial phase, wherein the top wall is domed so as to confolin to an
inner surface of the
exterior shell.
[0020] In yet another aspect, the invention relates to a protective helmet
comprising an
exterior shell, an interior liner placed inside the shell, and, disposed
between the shell and the
liner, at least one compressible cell comprising (i) an enclosure defining an
inner chamber and
comprising a top wall, a bottom wall, and side walls that resist yielding in
response to an impact
at least during an initial phase thereof, the top wall being domed so as to
confoim to an inner
surface of the exterior shell, and (ii) at least one orifice in the enclosure
for resistively venting
fluid from the inner chamber so as to at least partially attenuate the impact
after the initial phase.
[0021] In a further aspect, the invention pertains to a compressible cell
for use between an
exterior shell and an interior liner of an impact-attenuating helmet. In
various embodiments, the
cell comprises an enclosure including a top wall, a bottom wall, and side
walls that resist
yielding in response to an impact at least during an initial phase thereof,
the enclosure defining
an inner chamber for containing a fluid; and at least one orifice in the
enclosure for resistively
venting fluid from the inner chamber so as to at least partially attenuate the
impact after the
initial phase, wherein the enclosure is tapered at the top wall so as to fit
between the shell and
liner in a peripheral region of the helmet.
[0022] In another aspect, the invention relates to a protective helmet
comprising an exterior
shell; an interior liner placed inside the shell, where the distance between
the exterior shell and
the liner decreases in a peripheral region of the helmet; and disposed between
the shell and the
liner, at least one compressible cell comprising (i) an enclosure defining an
inner chamber and
comprising a top wall, a bottom wall, and side walls that resist yielding in
response to an impact
at least during an initial phase thereof, the enclosure being tapered at the
top wall so as to fit
between the shell and the liner in the peripheral region of the helmet, and
(ii) at least one orifice
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in the enclosure for resistively venting fluid from the inner chamber so as to
at least partially
attenuate the impact after the initial phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The foregoing will be more readily understood from the following
detailed
description, in particular, when taken in conjunction with the drawings, in
which:
[0024] FIG. 1A is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features side walls including an
exterior obtuse angle
and increasing in thickness toward the bottom plate;
[0025] FIG. 1B is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features side walls including an
exterior obtuse angle
and decreasing in thickness toward the bottom plate:
[0026] FIG. 1C is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features side walls of uniform thickness
that include an
interior obtuse angle;
[0027] FIG. 2A is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features corrugations in the top wall;
[0028] FIG. 2B is a schematic cut-away view of a shock absorber enclosure
in accordance
with one embodiment, which features nested cylindrical walls protruding from
the bottom wall;
[0029] FIG. 3A is a is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features a pin protruding from the
bottom wall opposite
an orifice through the top wall;
[0030] FIG. 3B is a schematic cross-sectional view of a shock absorber
enclosure in
accordance with one embodiment, which features a tubular protrusion extending
from the top
wall and surrounding an orifice therethrough;
[0031] FIG. 4 is an elevational view of a protective helmet with multiple
distributed
compression cells in accordance with one embodiment.
[0032] FIGS. 5A is a perspective sectional view of a shock absorber
enclosure in accordance
with one embodiment, side walls of varying thickness, a rounded top wall, and
corrugations
along the circumference of the top wall;
8
[0033] FIG. 5B is a sectional view of a shock absorber enclosure in
accordance with another
embodiment, which features varying wall thickness, corrugations along the
circumference of the top
wall, and a valve protruding from the top wall; and
[0034] FIG. 5C is a perspective sectional view of a shock absorber
enclosure similar to that of
FIG. 5A, which further tapers off toward one side so as to better fit into
peripheral space of a
protective helmet.
DETAILED DESCRIPTION
[0035] Shock absorbers in accordance herewith can be fabricated from a
variety of elastic and
semi-elastic materials, including, for example, rubbers, thermoplastics, and
other moldable polymers.
A particularly suited material, due its durability, resiliency, and
amenability to blow molding or
injection molding, is thermoplastic elastomer (TPE); commercially available
TPEs include the
ARNITEL and SANTOPRENE brands. Other materials that may be used include, for
example,
thermoplastic polyurethane elastomers (TPUs) and low-density polyethylene
(LDPE). In general, the
material selection depends on the particular application, and can be readily
made, without undue
experimentation, by a person of skill in the art based on known material
properties. Further, the
desired shape and configuration of the shock absorber enclosure can generally
be created using any
of a number of well-known manufacturing techniques, such as, e.g., blow
molding or injection
molding. The shock absorber may be manufactured in one piece, or in two or
more parts that are
subsequently bonded together to form a fluid-tight enclosure. Bonding may be
accomplished, for
example, with an adhesive (such as glue), or using a thermal bonding process.
Mechanically
interlocking features, clamps, or similar devices may be used to assure that
the multiple parts remain
affixed to each other.
[0036] FIG. IA schematically illustrates an exemplary shock absorber cell
100 in accordance
with various embodiments. The cell includes a flat bottom plate 102 and,
secured thereto, a cap 104
forming the top wall 106 and side walls 108 of the structure. An orifice or
vent 110 through the top
wall 106 allows fluid to exit from the interior chamber 112 formed by the cell
enclosure as the cell is
compressed during an impact, as well as to enter the chamber as the cell
returns to its original shape
following the impact. Although only one orifice is shown, various embodiments
use multiple
orifices of the same or different shapes and sizes. The orifice(s) need not go
through the top wall, but
may generally be located in any portion of the cell enclosure.
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Further, instead of being simple holes or slits, the orifices may be equipped
with valve structures
that regulate flow therethrough. For example, in some embodiments. check
valves that allow
only inflow are provided at the bottom wall of the cell, and check valves that
permit only outflow
are included in the top wall, or vice versa.
[00371 Returning to FIG. 1A, the side walls 108 form two back-to-back
frustoconical
portions that meet with their narrower end at a horizontal plane located
between the top and
bottom walls 106, 102, such that they define an obtuse exterior angle a. Thus,
when the cell 100
collapses, the side walls 108 move inward toward a central axis 114 of the
cell, thereby reducing
the volume of the cell and further compressing the air therein. This may
result in increased
turbulence of the air escaping through the orifice 110 and, thus, in increased
resistance to
compression. Further, as shown, the side walls 108 increase in thickness
between the top and
bottom walls. As a result, the resistance that the walls 108 themselves
provide to the impact
increases steadily throughout the duration of the compression. As will be
readily apparent to one
of skill in the art, variations of the wall thickness along its height can
generally be used to tailor
the temporal energy management profile of the cell, as characterized, for
example, in terms of
the residual force transmitted through the cell as a function of time.
[0038] FIG. 1B illustrates an alternative compression cell 120, in which
the thickness of the
side walls 128 increases toward the top wall 106. (Other than that, the cell
120 is similar to the
cell 100 depicted in FIG. 1A.) The thin portion 130 of the wall 128 near the
bottom plate 102
constitutes a "weak spot" of the cell enclosure, which allows the cell to
initially shear in response
to an impact force that includes a component parallel to the top surface
(i.e., a tangential force).
thereby dissipating tangential forces. During later phases of the impact,
energy is absorbed via
compression of the thicker wall portions near the top wall 106.
100391 FIG. 1C shows yet another shock absorber structure 140, which
includes walls of
substantially uniform thickness. In this embodiment, the side walls 148 are
angled so as to
define an interior obtuse angle [3, and, consequently, they collapse
outwardly. Accordingly, the
cell enclosure provides somewhat lower resistance to collapse then that of the
cells 100, 120 with
inverted walls depicted in FIGS. 1A and 1B. These and other cell wall designs
may be combined
with additional features as described below.
[0040] In some embodiments, the top and/or bottom walls of the shock
absorber are not flat
(as depicted in FIGS. 1A-1C). but include corrugations or features vertically
protruding
CA 02797170 2012-11-29
therefrom. Such features can provide increased resistance during late stages
of cell compression.
For example, FIG. 2A shows a shock-absorber cell 200 with one or more "V-
shaped"
corrugations 202 around a periphery of the top wall 204. As the cell is 200
compressed, the top
wall 204 approaches the bottom wall 206, and the lowest points 208 of the
corrugations 202
eventually contact the bottom wall 206. Effectively, this increases the number
of side walls
against which the impact forces work and, thus, inhibits further compression
of the cell 200. As
a result, the shock absorber cell 200 can withstand larger impact forces
before it bottoms out.
Moreover, flexure of the corrugations 202 facilitates lateral motion of the
center region of the top
wall 204 relative to the periphery in response to shear forces. Thus, in
addition to increasing the
cell's resistance to normal forces, the corrugations 202 help dissipating
shear forces.
[0041] FIG. 2B illustrates another design for a shock-absorbing cell 220,
in which a plurality
of concentric circular ridges 222 are arranged on the bottom wall 224. When
the top wall
reaches these ridges 222 during compression of the cell 220, the ridges 222
begin contributing to
the absorption of the impact, resulting in a higher overall resistance of the
shock absorber to
compression. The above-described corrugations and vertically protruding
features are merely
examples; corrugations and protrusions of different shapes and configurations,
attached to the
top wall, the bottom wall, or both, may likewise be used to achieve similar
effects.
[0042] FIGS. 3A and 3B illustrate shock absorbers in which the
configuration of the orifice
and, consequently, the rate of fluid flow therethrough change depending on the
compression state
of the cell. For example, FIG. 3A shows a compression cell that includes a
long, conical pin 302
protruding from bottom wall 304 opposite an orifice 306 through the top wall
308. Once the cell
300 has been sufficiently compressed in response to the impact (e.g., to about
half its original
height as shown in the figure), the pin 302 is received within and penetrates
the orifice 306,
thereby reducing the area through which fluid can escape. Eventually the pin
302 completely
obstructs the orifice, preventing any further fluid-venting. Thus, the orifice
306 and pin 302
together function as a valve.
[00431 FIG. 3B shows an alternative embodiment 320, in which valve-like
behavior is
created by a tubular protrusion 322 that extends vertically downward from the
top wall 324 and
includes a lumen 326 therethrough. The tubular protrusion 322 can restrict
fluid-venting via two
mechanisms. As can be readily seen, fluid venting through the lumen 326
requires the fluid to
enter the tube 322 at the end 328 close to the bottom wall 330. Accordingly,
as this end 328
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contacts the bottom wall, venting is precluded or at least inhibited. In
addition, and generally
more importantly, the tube 322 can be made of a thickness and material that
allows it to constrict
and self-restrict the orifice in response to increased fluid turbulence, much
like a balloon that
releases air through the opening.
[0044] Shock absorbers as described above may employed advantageously in a
variety of
applications, including, for example, protective body gear, vehicle dash
boards, and shock-
absorbing seats. FIG. 4 illustrates, as one exemplary application, a
protective helmet 400
including multiple compression cells 402 distributed between a shell and a
helmet liner. The
shock absorbers 402 may include any combination of the features described
above. Further, they
may be shaped to accommodate the space between the shell and liner. For
example, FIG. 5A
shows a shock absorber cap 500A (omitting the bottom wall) that has an
elevated, rounded top
wall 502 with a curvature complementary to that of the interior surface of the
helmet shell.
Further, the shock absorber features one or more "V-shaped" corrugations 202
around the
periphery of the top wall 502, and inwardly angled side walls 505 with that
increase in thickness
toward the bottom. The rounded top wall and corrugation(s) cooperate to allow
the cell top to
shift laterally in response to shear forces.
[0045] FIG. 5B illustrates a shock absorber 500B suitable for use in areas
of the helmet that
curve back in toward the head, e.g., the occipital lock area on the back of
the helmet and the
areas on the lower sides. The shock absorber 500B has an elevated, rounded top
wall 502 with a
curvature complementary to that of the interior surface of the helmet shell.
Further, the shock
absorber features one or more "V-shaped" corrugations 202 around the periphery
of the top wall
502, and inwardly angled side walls 505 with that increase in thickness toward
the bottom. The
enclosure of this shock absorber tilts toward one side, i.e., the side wall
height decreases across a
diameter of the shock absorber such that, properly placed, it sits flush
against the shell. The
shock absorber 500B includes a tubular protrusion 322 that extends vertically
downward from the
top wall 502 and includes a lumen therethrough. The radial grooves illustrated
in FIGS. 5A and
5B are vents that permit air to travel over the surface of the shock absorber
upon impact.
[0046] FIG. 5C illustrates another shock-absorbing cell 500c having side
walls whose
collective height decreases across a diameter of the shock absorber to confonn
to a space of non-
uniform height. This cell combines side walls 502 toeing in toward a medial
plane and
increasing in thickness toward the bottom, corrugations 202 in the top wall,
and a plurality of
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concentric circular ridges 222 arranged on the bottom wall 506. These features
cooperate to increase
the cell's resistance to compression as a highly compressed state is reached
and, thus, collectively
increase the energy levels that can effectively be absorbed without increasing
the height of the shock
absorber structure.
100471 Certain embodiments of the present invention are described above. It
is, however,
expressly noted that the present invention is not limited to those
embodiments; rather, additions and
modifications to what is expressly described herein are also included within
the scope of the
invention. Moreover, it is to be understood that the features of the various
embodiments described
herein are not, in general, mutually exclusive and can exist in various
combinations and
permutations, even if such combinations or permutations are not made express
herein, without
departing from the spirit and scope of the invention. In fact, variations,
modifications, and other
implementations of what is described herein will occur to those of ordinary
skill in the art without
departing from the spirit and the scope of the invention. As such, the
invention is not to be defined
only by the preceding illustrative description.
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CA 2797170 2019-01-30
