U.S. patent application number 17/162837 was filed with the patent office on 2021-05-20 for energy dissipating helmet.
This patent application is currently assigned to William A. Jacob. The applicant listed for this patent is William A. Jacob. Invention is credited to William J. Jacob.
Application Number | 20210145105 17/162837 |
Document ID | / |
Family ID | 1000005371137 |
Filed Date | 2021-05-20 |
![](/patent/app/20210145105/US20210145105A1-20210520-D00000.png)
![](/patent/app/20210145105/US20210145105A1-20210520-D00001.png)
![](/patent/app/20210145105/US20210145105A1-20210520-D00002.png)
![](/patent/app/20210145105/US20210145105A1-20210520-D00003.png)
![](/patent/app/20210145105/US20210145105A1-20210520-D00004.png)
United States Patent
Application |
20210145105 |
Kind Code |
A1 |
Jacob; William J. |
May 20, 2021 |
Energy Dissipating Helmet
Abstract
An energy dissipating helmet, such as a protective football
helmet, includes a structural component, such as a hard plastic
outer shell, adapted to receive an anticipatory impact having
energy, and configured to be caused to resistively collapse by the
impact, such that the component dissipates at least a portion of
the energy, wherein the component may further include an active
material element for further energy dissipation during and/or to
facilitate repair after receiving the impact.
Inventors: |
Jacob; William J.; (Kansas
City, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jacob; William A. |
|
|
US |
|
|
Assignee: |
Jacob; William A.
Kansas City
MO
|
Family ID: |
1000005371137 |
Appl. No.: |
17/162837 |
Filed: |
January 29, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13894423 |
May 14, 2013 |
|
|
|
17162837 |
|
|
|
|
61646596 |
May 14, 2012 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A42B 3/12 20130101; A42B
3/125 20130101 |
International
Class: |
A42B 3/12 20060101
A42B003/12 |
Claims
1. A protective football helmet configured to fit upon the head of
a user, to receive an anticipatory impact having energy on a
predefined area of the helmet, and to dissipate a portion of the
energy, so as to not transfer said portion of energy to the user,
when the impact is received on said predefined area, said football
helmet comprising: an outer shell of durable material defining an
exterior surface adapted to receive the impact, presenting a front
elevation and a back elevation opposite the front elevation, and
including a left side portion, a right side portion, and a dorsal
portion longitudinally extending from the front elevation and to
the back elevation, wherein the dorsal portion is intermediate the
left side portion and the right side portion, wherein the left side
portion, the right side portion, and the dorsal portion
cooperatively define an inverted U-shaped opening operable to
receive a facemask, in the front elevation, wherein the opening is
defined by opposite vertical edges defined by the left side portion
and the right side portion respectively, and an interconnecting
cross-edge cooperatively defined by the left side portion, the
right side portion, and the dorsal portion, said shell defining at
least one compliant energy dissipating section disposed within the
front elevation and the dorsal portion, wherein said at least one
compliant energy dissipating section is configured to resistively
collapse towards the head, so as to achieve an impact condition and
dissipate said portion of the energy, when receiving the impact,
said shell further defining a rigid, non-active section in each of
the left side portion and the right side portion, wherein the
non-active sections are configured so as to not achieve the
condition and not dissipate said portion of the energy, when each
receives the impact; and interior padding adapted to engage the
head when the helmet is donned, and configured to be compressed
when the shell receives the anticipatory impact.
2. The helmet as claimed in claim 1, wherein the shell is formed of
an injection molded hard plastic.
3. The helmet as claimed in claim 1, wherein the left side portion,
the right side portion, and the dorsal portion are integrally
formed, such that the shell presents a unitary and non-modular
structure.
4. The helmet as claimed in claim 1, wherein the shell defines an
overall width and overall height in the front elevation, the dorsal
portion presents a uniform width not more than 70% of the overall
width, and the side portions present a height not less than 90% of
the overall height.
5. The helmet as claimed in claim 4, wherein the dorsal portion
presents a uniform width not more than 60% of the overall width,
and the side portions present a height not less than 95% of the
overall height.
6. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section is laterally centered within the
dorsal portion.
7. The helmet as claimed in claim 1, said at least one compliant
dissipation section is spaced from the opening.
8. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section defines at least one through-hole,
said at least one through-hole being configured to facilitate said
at least one compliant dissipating section resistively collapsing
towards the head, when the helmet is donned and receives the
impact.
9. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section is configured to inelastically
deform, when receiving the impact.
10. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section presents an original shape, achieves
an impact condition when receiving the impact, and includes a
return element operable to drive said at least one compliant
dissipating section towards the original shape when in the impact
condition.
11. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section presents at least one of a
through-hole, a geometric configuration, a thinner layer, or a
fold-line operable to facilitate said at least one dissipating
section resistively collapsing towards the head, when the helmet is
donned and receives the impact.
12. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section is configured to resistively collapse
by folding towards the head, when receiving the impact.
13. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section and the non-active sections form
separate interconnected parts, so as to define a seam therebetween,
and said at least one compliant dissipating section and the
non-active sections are reversibly disconnectable.
14. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section and the nonactive sections
cooperatively define at least one male member and at least one
orifice, and are interconnected by inserting said at least one male
member into said at least one orifice.
15. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section is viewable in the front and back
elevations.
16. The helmet as claimed in claim 1, wherein said at least one
compliant dissipating section composes a composite shell, said
composite shell including a rigid inner layer and an outer layer at
least partially spaced from the inner layer and resistively
collapsible towards the inner layer by the impact.
17. The helmet as claimed in claim 16, wherein the composite shell
further includes a compressible medium interposed between the inner
and outer layers.
18. A protective football helmet configured to fit upon the head of
a user, receive an anticipatory impact having energy, and dissipate
a portion of the energy when the impact is received, said football
helmet comprising: a composite shell defining an exterior surface,
and including an inner layer and an outer layer at least partially
spaced from the inner layer, wherein the outer layer is caused to
resistively collapse towards the inner layer by the impact, so as
to dissipate said portion of energy, said outer layer defining the
exterior surface and an original shape, adapted to receive the
impact, and presenting a compliant energy dissipating section
configured to resistively collapse towards the head, so as to
achieve an impact condition and dissipate said portion of the
energy, when receiving the impact, said inner layer defining a
rigid, non-active section configured so as to not achieve the
condition and not dissipate said portion of the energy, when
receiving the impact; a compressible medium intermediate the inner
layer and outer layer, and operable to drive the outer layer
towards the original shape when in the impact condition; and
interior padding interior to the shell, adapted to engage the head
when the helmet is donned, and configured to be compressed when the
shell receives the impact.
19. The helmet as claimed in claim 18, wherein the compressible
medium includes a plurality of tubular elastic members orthogonally
interconnecting the inner and outer layers.
20. The helmet as claimed in claim 18, wherein the outer layer
presents a first thickness, and the inner layer presents a second
thickness greater than the first thickness.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This U.S. Non-Provisional patent application claims priority
to and the benefit of pending U.S. application Ser. No. 13/894,423,
filed on May 14, 2013, and U.S. Provisional application Ser. No.
61/646,596, filed on May 14, 2012, the disclosures of which being
incorporated by reference herein.
BACKGROUND
1. Field of the Invention
[0002] The present disclosure relates to protective helmets
offering energy dissipating functionality, and to protective
helmets that utilize active material activation to dissipate the
energy during and/or restore the helmet after an impact.
2. Discussion of Prior Art
[0003] A variety of protective helmets have been developed to
protect a user (e.g., an athlete) against injury resulting from an
impact to the head, as often required. For example, in the sports
of football, hockey, and baseball, players typically don helmets
during play to protect their head, neck, face, and spine from
catastrophic injury, which may result from an impact by another
player or the ground during a tackle, by a baseball pitch or hockey
puck gone awry, etc. Construction of these helmets typically
include a rigid outer shell formed of an injected molded hard
plastic, interior padding typically formed of vinyl, foam,
polypropelene, or similar material that absorb energy mechanically,
and a metal alloy facemask.
[0004] Conventional helmets have been shown to effectively protect
against some injuries, such as skull fractures, but present various
concerns in other areas even when used properly. For example,
concussions and spinal injury remain problematic, especially in
football, due, in part, to the transfer of energy to the player.
More particularly, it has been reported that at least 43,000
high-school football players in the United States suffer
concussions each year; and despite special rules that prevent
"spearing," spinal cord injuries remain a concern, especially in
secondary school and younger aged players who often do not possess
the necessary skill to execute a proper form tackle. Moreover,
conventional helmets do not offer indication or an alert that such
an impact has occurred.
[0005] Thus, there remains a need in the art for an improved
protective helmet that, among other things, reduces the likelihood
of concussions and spinal injury, and offer indication that such an
impact has occurred.
BRIEF SUMMARY
[0006] The present invention concerns a protective helmet adapted
for use by a user, and to receive an anticipatory impact having
energy. The helmet is operable to absorb (i.e., dissipate) at least
a portion of the energy, so as to not transfer said portion of the
energy to the user, and/or to facilitate repair after receiving the
impact. The helmet comprises a structural component presenting an
original shape and configured to receive and be elastically or
inelastically deformed (i.e., resistively collapsed) by the impact,
so as to absorb said portion of the energy. In some embodiments,
wherein energy dissipation is provided only within a predetermined
area of the helmet (e.g., the dorsal portion of a football helmet
shell), the invention is useful for providing a dually functional
helmet that provides energy dissipation where desired, while
maintaining conventional (e.g., deflective) capabilities in other
areas (e.g. the side portions of a football helmet shell). In
further embodiments, the helmet employs a stress activated active
material element to further dissipate energy during an impact.
Thus, the invention is useful for reducing the amount of energy
that is transferred to the head, neck, and/or spine of a user, and
therefore, for reducing the likelihood of injuries, including
concussions and spinal injury that may occur from an impact to the
head of an athlete. Whereas conventional helmets temporarily absorb
energy through compression of various foams or padding materials
and subsequently release the stored energy (to the user) through
decompression and equilibration once the impact subsides, the
present invention provides a novel method of dissipating energy
(i.e., removing at least a portion of the energy from the transfer
all together).
[0007] More particularly, where shape memory allow is employed, the
hysteresis loop of the material as it goes from Austenite to
Martensite and then back to Austenite defines the amount of energy
dissipated (the higher above Af the more energy required to
transform), another benefit of the invention is in concussion
prevention. In a preferred embodiment, transformation to the more
malleable state will occur at some point during head travel/padding
compression, thereby making it easier to continue to
travel/compress. This is contrary and advantageous to conventional
helmet padding materials that apply increasingly greater resistance
as they are compressed even though the user is decelerating, which
accelerates the stop. In the present invention, transformation
results in greater resistance at the beginning (when acceleration
is greatest), and reduced resistance at a subsequent point, where
acceleration has lessened. Moreover, greater travel is enabled,
where the inventive interior padding is able to achieve a thinner
collapsed profile in its Martensitic form than a resistively
equivalent conventional pad. Thus, by reducing the resistance
offered by the pad during impact, and increasing the available
travel distance, concussions are deterred.
[0008] As a result, the invention is useful for improving the
safety of users during activities, such as playing football,
baseball, or hockey, conducting military, factory, or construction
operations, or operating a bicycle, motorcycle, or
all-terrain-vehicle (ATV), and therefore for providing
psychological reassurance to the user, family members of the user,
and others during such activities. The invention is yet further
useful for providing a method of retrofitting or reconditioning
existing helmets in a manner that improves upon their original
functionality. Finally, in a preferred embodiment, the invention
may be used to produce an alert that an impact has occurred, and
therefore may be used as a training tool to teach proper tackling
technique, or a diagnostic tool to indicate a desire to assess the
user.
[0009] In general, the invention presents an energy-dissipating
helmet adapted for use by a user, to receive an anticipatory impact
having energy, and to dissipate at least a portion of the energy,
so as to not transfer the portion of energy to the user. The helmet
includes a structural component (e.g., shell) configured to receive
the impact, undergo a greater amount of deformation so as to
dissipate a greater portion of the impact energy, and in some
embodiments, further includes an active material element, such as a
normally Austenitic shape memory alloy wire, mesh, matrix, or
spring, operable to undergo a reversible change in fundamental
property when exposed to a stress activation signal. The element is
communicatively coupled to the component and configured such that
it receives the impact, the impact produces the stress activation
signal, and the change in fundamental property causes or further
causes the dissipation of energy.
[0010] Other aspects and advantages of the present invention,
including embodiments wherein various active material elements
compose the shell, interior padding, or facemask may be understood
more readily by reference to the following detailed description of
the various features of the disclosure and the examples included
therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Preferred embodiments of the invention are described in
detail below with reference to the attached drawing figures of
exemplary scale, wherein:
[0012] FIG. 1 is a front elevation of a football helmet comprising
a rigid outer shell presenting dorsal energy dissipating and side
non-active sections inter-engaged by a plurality of pins, and an
active material mesh disposed within the energy dissipating
section, and further comprising interior padding having Austenitic
SMA wire (shown in hidden-line type) entrained within its cushion
material and fixedly anchored by the shell, in accordance with a
preferred embodiment of the invention;
[0013] FIG. 1a is a side elevation of the football helmet shown in
FIG. 1;
[0014] FIG. 1b is a partial front elevation of a football helmet
comprising a dorsal dissipating section presenting at least one
through-hole, a fold line and lateral slopes extending from the
fold line, in accordance with a preferred embodiment of the
invention;
[0015] FIG. 2 is a back elevation of the football helmet shown in
FIG. 1, further illustrating the sections, and in enlarged caption
view, the active mesh;
[0016] FIG. 2a is an exemplary cross-section of an energy
dissipating section taken along lines A-A in FIG. 1, illustrating
an outer shell formed by outer and inner layers spaced by air, and
interior padding comprising non-active cushion material, wherein
the outer layer includes an active material continuous sheet, in
accordance with a preferred embodiment of the invention;
[0017] FIG. 3 is a front elevation of a football helmet after an
impact has caused an inelastic deformation in the energy
dissipating section, in accordance with a preferred embodiment of
the invention;
[0018] FIG. 4 is an exemplary cross-section of an energy
dissipating section, illustrating an outer shell comprising outer
and inner layers spaced by an active medium, and interior padding
comprising non-active cushion material and active material springs
or coils disposed within cutouts defined by the material, in
accordance with a preferred embodiment of the invention;
[0019] FIG. 4a is an exemplary cross-section of an energy
dissipating section comprising an outer shell formed of outer and
inner layers spaced by an active medium further comprising a
plurality of active spheres embedded within a compressible
substrate, in accordance with a preferred embodiment of the
invention;
[0020] FIG. 4b is an exemplary cross-section of an energy
dissipating section comprising an outer shell, a compressible
active layer disposed adjacent the shell, and non-active cushion
material adjacent the layer, in accordance with a preferred
embodiment of the invention;
[0021] FIG. 4c is an exemplary cross-section of an energy
dissipating section comprising an outer shell, an active polygonal
sheet defining faces and vertices fixedly coupled to the shell, and
non-active cushion material adjacent the sheet, in accordance with
a preferred embodiment of the invention;
[0022] FIG. 4d is an exemplary cross-section of an energy
dissipating section comprising an outer shell formed of outer and
inner layers spaced by a plurality of tubular elastic members, or
compression springs coupled and orthogonally oriented relative to
the engaging surfaces of the layers, in accordance with a preferred
embodiment of the invention;
[0023] FIG. 5 is an elevation of an active material spring, e.g.,
to be disposed within the cutouts shown in FIG. 4, in a collapsed
condition and mechanically connected in series to a non-active
spring, in accordance with a preferred embodiment of the
invention;
[0024] FIG. 6 is a side elevation of a bicycle helmet comprising
energy dissipation along its entire outer surface, in accordance
with a preferred embodiment of the invention;
[0025] FIG. 7 is a perspective view of a baseball helmet comprising
side energy dissipating sections, and a dorsal non-active section,
in accordance with a preferred embodiment of the invention;
[0026] FIG. 8 is a side elevation of a hockey helmet including a
facemask, and a shell further comprising front and back energy
dissipating sections, and a non-active section, in accordance with
a preferred embodiment of the invention;
[0027] FIG. 9 is a perspective view of a construction, factory, or
military hard hat/helmet comprising a top energy dissipating
section, in accordance with a preferred embodiment of the
invention;
[0028] FIG. 10 is a perspective view of a motorcycle helmet
presenting energy dissipation along its entire outer surface, in
accordance with a preferred embodiment of the invention; and
[0029] FIG. 11 is a back elevation of a football helmet comprising
piezoelectric composite elements communicatively coupled to
resistive elements and luminaries, in accordance with a preferred
embodiment of the invention.
DETAILED DESCRIPTION
[0030] In a preferred embodiment of the present invention, a
protective football helmet is configured to fit upon the head of a
user, to receive an anticipatory impact having energy on a
predefined area of the helmet (e.g., the shell, facemask etc. (in
whole or in part)), and to dissipate a portion of the energy, so as
to not transfer said portion of energy to the user, when the impact
is received only on said predefined area. For example, the football
helmet may comprise an outer shell of durable material defining an
exterior surface adapted to receive the impact, and presenting a
front elevation and a back elevation opposite the front elevation.
The shell includes a left side portion, a right side portion, and a
dorsal portion, said portions longitudinally extending preferably
from within the front elevation to within the back elevation. The
dorsal portion is intermediate the left side portion and the right
side portion, and may define an elongated medial strip having
parallel sides. The left side portion, the right side portion, and
the dorsal portion cooperatively define an inverted U-shaped
opening operable to receive a facemask, in the front elevation. The
opening is defined by opposite vertical edges defined by the left
side portion and the right side portion, which extend along the
sides of the user's face, and an interconnecting cross-edge
cooperatively defined by the left side portion, the right side
portion, and the dorsal portion that extends across the user's
forehead, when donned. The preferred shell defines at least one
compliant energy dissipating section disposed within the front
elevation and the dorsal portion. The compliant energy dissipating
section(s) is configured to resistively collapse towards the head,
so as to achieve an impact condition and dissipate said portion of
the energy, when receiving the impact. In this regard, it is
appreciated that "resistively collapse/collapsing" instructs that
the dissipating section is configured so as to require said portion
of energy to deform, wherein the more resistive to collapse the
greater the required energy. The shell further defines a rigid,
non-active section in each of the left side portion and the right
side portion, wherein the non-active sections are configured so as
to not achieve the condition and not dissipate said portion of the
energy (i.e., maintain its deflective capability), when each
receives the impact. The helmet further comprises interior padding
adapted to engage the head when the helmet is donned, and
configured to be compressed when the shell receives the
anticipatory impact, and a facemask.
[0031] The preferred shell may be formed of an injection molded
hard plastic. The left side portion, the right side portion, and
the dorsal portion may be integrally formed, such that the shell
presents a unitary and non-modular structure. Where the shell may
define an overall width and overall height in the front elevation,
the preferred dorsal portion may present a uniform width not more
than 70% of the overall width, and the preferred side portions may
present a height not less than 90% of the overall height; most
preferably, the dorsal portion may present a uniform width not more
than 60% of the overall width, and the side portions may present a
height not less than 95% of the overall height. The preferred
dissipating section(s) may be laterally centered within the dorsal
portion; spaced from the opening; be viewable in the front and back
elevations; define at least one through-hole configured to
facilitate resistive collapsing towards the head; and be configured
to inelastically deform, when receiving the impact. Where the
dissipating section(s) presents an original shape, achieves an
impact condition when receiving the impact, it may include a return
element operable to drive the dissipating section(s) towards the
original shape when in the impact condition. The dissipating
section(s) may present at least one of a through-hole, a geometric
configuration, a thin layer of hard plastic, or a fold-line
operable to facilitate resistively collapsing towards the head,
when receiving the impact, and as such, may be configured to
resistively collapse by folding towards the head. For example, both
a thinner layer of hard plastic (FIG. 1), with or without the
active-material mesh interposed therein, may be combined with a
geometric configuration and/or fold-line defined by a through-hole
(FIG. 1b) to provide a dorsal energy dissipation section and an
area of even greater energy dissipation within the dissipating
section. The dissipating section(s) may present a composite shell
including an inner layer and an outer layer at least partially
spaced from the inner layer, wherein the outer layer is caused to
resistively collapse towards the inner layer by the impact, and a
compressible medium interposed between the inner and outer layers.
The dissipating section(s) and the non-active sections may form
separate interconnected parts, so as to define a seam therebetween
and be reversibly disconnectable. To that end, the dissipating
section(s) and nonactive sections may cooperatively include at
least one male member and defines at least one orifice, such that
the dissipating section(s) and the nonactive sections are
interconnected by inserting the male member(s) into the
orifice(s).
[0032] In another preferred embodiment of the invention, a
protective football helmet is configured to fit upon the head of a
user, receive an anticipatory impact having energy, and dissipate a
portion of the energy when the impact is received. The football
helmet comprises a composite shell defining an exterior surface and
includes an inner layer and an outer layer at least partially
spaced from the inner layer. The outer layer is caused to
resistively collapse towards the inner layer by the impact, so as
to dissipate said portion of energy. The outer layer defines the
exterior surface and an original shape, is adapted to receive the
impact, and presents a compliant energy dissipating section
configured to resistively collapse towards the head, so as to
achieve an impact condition and dissipate said portion of the
energy, when receiving the impact. The inner layer defines a rigid,
non-active section configured so as to not achieve the condition
and not dissipate said portion of the energy, when receiving the
impact. A compressible medium is disposed intermediate the inner
layer and outer layer, and operable to drive the outer layer
towards the original shape when in the impact condition. Finally,
the helmet includes interior padding that is interior to the shell,
adapted to engage the head when the helmet is donned, and
configured to be compressed when the shell receives the impact, as
well as a facemask. More preferably, the compressible medium
includes a plurality of tubular elastic members orthogonally
inter-connecting the inner and outer layers; and the outer layer
presents a first thickness, and the inner layer presents a second
thickness greater than the first thickness.
[0033] Turning to FIGS. 1-10, the present invention concerns a
protective helmet 10 operable to dissipate energy and provide the
aforementioned benefits. More particularly, the helmet 10 is
adapted for use by a user (not shown) during an activity, and
configured to receive an anticipatory impact producing a total
energy and dissipate at least a portion of the energy, so as to not
transfer the portion to the user, wherein an "anticipatory impact"
is an impact of type and magnitude typically encountered during the
activity that has the potential to cause injury to the user. In the
exemplary embodiments shown in FIGS. 1, 2, and 3, the helmet 10
presents a football helmet in a traditionally upright orientation.
The helmet 10 is shown in a front elevation (FIGS. 1,3), a side
elevation (FIG. 1a), and a back elevation (FIG. 2). As best shown
in FIG. 1, the helmet comprises a shell 14 including a left side
portion, a right side portion, and a dorsal portion intermediate
the left side and right side portions, when viewed in the front or
back elevations. The shell 14 is configured so as to define a
continuous exterior surface, and a downward-facing concavity that
enables a user's head (not shown) to be inserted securely therein,
such that the shell 14 overlays and protects a majority of the
user's skull.
[0034] As used herein, the term "dorsal portion" generally defines
that portion of the shell intermediate the side sections. It may
present an elongated medial strip having parallel sides that
longitudinally extend from the front elevation (FIG. 1, leader
lines of W3) and to the back elevation (FIG. 2), or sinuous sides,
so as to present an enlarged front and rear sections (compare FIGS.
1,2 to FIGS. 7,9). As such, the dorsal portion defines the crown or
apex of the helmet 10. The left side portion, the dorsal portion,
and the right side portion cooperatively define the exterior
surface. As shown in FIGS. 1,2, the left side portion, the right
side portion, and the dorsal portion cooperatively define, in the
upright orientation and front elevation (FIG. 1), an inverted
U-shaped opening operable to receive a facemask 18. The opening is
defined by opposite vertical edges defined by the left side portion
and the right side portion, and an interconnecting cross-edge
defined by the left side portion, the right side portion, and the
dorsal portion. As such, the preferred dorsal portion presents a
maximum lateral extent that is less than the width of the
cross-edge of the U-shaped opening. Finally, the dorsal portion is
laterally centered (FIGS. 1,2), such that the left side and
right-side portions are congruent. In the embodiment shown in FIG.
1, where the football helmet shell 14 presents a maximum overall
width, W2 (e.g., approximately 10 in.), and height, H2 (e.g.,
approximately 12 in.), the dorsal portion may present a medial
strip of uniform width, W3 (e.g., approximately 6 in. or 60% of the
maximum shell width), such that the side portions present widths
equal to (W2-W3)/2 (e.g., approximately 2 in. or 20% of the maximum
shell width). In this configuration, it is appreciated that the
non-active side portion would present a height, H3 (e.g.,
approximately 11.36 in. or 95% of the maximum shell height). More
preferably, the dorsal portion width is not more than 70% of the
overall shell width, and the side portion height is not less than
90% of the overall shell height.
[0035] In some embodiments, the helmet 10 employs stress activated
active material actuation to further dissipate energy during an
impact. In these embodiments, the helmet 10 comprises a
stress-activated active material element 12 configured to receive
the impact, convert at least a portion of its energy into a stress
activation signal, and dissipate energy by using the signal to
reversibly and spontaneously transform the active material as
further described below. The dissipating section 22, including the
element 12, dissipates a minimum portion, more preferably, at least
10%, and most preferably, at least 25% of the energy, so as to
effect a measurable impact upon the impact. Finally, it is
appreciated that the advantages and benefits of the present
invention may be applied wherever protective helmets are used; for
example, the invention may be used in association with football,
baseball, hockey, lacrosse, and other contact sports, while
operating a bicycle, motorcycle, ATV, or other vehicle, and while
working in potentially injurious settings, such as construction,
factory, and military/combat applications.
[0036] An active material particularly suited for use in the
present invention is shape memory alloy in a normally Austenite
phase (i.e., having a phase transition temperature less than
ambient temperature); however, it is well within the ambit of the
invention to utilize any stress-activated active material, as
equivalently presented herein, or modified as necessary. As used
herein the term "active material" is to be given its ordinary
meaning as understood and appreciated by those of ordinary skill in
the art; and thus includes any material or composite that undergoes
a reversible fundamental (e.g., intensive physical, chemical, etc.)
property change when activated by an external stimulus or
signal.
[0037] Shape memory alloys (SMA's) generally refer to a group of
metallic active materials that demonstrate the ability to return to
some previously defined shape or size when subjected to an
appropriate thermal stimulus. Shape memory alloys are capable of
undergoing phase transitions in which their yield strength,
stiffness, dimension and/or shape are altered as a function of
temperature, and therefore, exist in several different
temperature-dependent phases. The most commonly utilized of these
phases are Martensite and Austenite phases. The Martensite phase
generally refers to the more deformable, lower temperature phase
whereas the Austenite phase generally refers to the more rigid,
higher temperature phase. When the shape memory alloy is in the
Martensite phase and is heated, it begins to change into the
Austenite phase and recover a "memorized" shape. The temperature at
which this phenomenon starts is often referred to as Austenite
start temperature (A.sub.s). The temperature at which this
phenomenon is complete is called the Austenite finish temperature
(A.sub.f).
[0038] In the Austenite phase, a stress induced phase change to the
Martensite phase exhibits a superelastic (or pseudoelastic)
behavior that refers to the ability of SMA to return to its
original shape upon unloading after a substantial deformation in a
two-way manner. That is to say, application of increasing stress
when SMA is in its Austenitic phase will cause the SMA to exhibit
elastic Austenitic behavior until a certain point where it is
caused to change to its lower modulus Martensitic phase, where it
then exhibits elastic Martensitic behavior followed by up to 8% of
superelastic deformation. Removal of the applied stress will cause
the SMA to switch back to its Austenitic phase in so doing
recovering its starting shape and higher modulus, as well as
dissipating energy under the hysteretic loading/unloading
stress-strain loop. Moreover, it is appreciated that the
application of an externally applied stress causes Martensite to
form at temperatures higher than M.sub.s. Superelastic SMA can be
strained several times more than ordinary metal alloys without
being plastically deformed, however, this is only observed over a
specific temperature range, with the largest ability to recover
occurring close to A.sub.f.
[0039] Returning to the helmet configuration, the active material
element 12 may be communicatively coupled to or compose any
structural component (i.e., predetermined area) of the helmet 10
that is anticipated to receive an anticipatory impact. Inventively,
the active material element 12, such as an Austenitic (or
"superelastic") shape memory alloy wire, mesh, layer, or spring, is
activated by the impact, and more particularly, by stress induced
therefrom, so as to dissipate at least a portion of its energy. For
example, the structural component may present and the element 12
may compose or be communicatively coupled to a rigid outer shell
14, interior padding 16, and/or facemask/shield 18 composing the
helmet 10. The term "interior padding 16" shall include all
components of the helmet interior to the shell 14 and generally
functional to protect the user during impact. As previously stated
with respect to FIGS. 1, 2, 3, and 10, the shell 14 includes a left
side portion, a right side portion, and a dorsal portion defining a
crown, wherein the left side portion, the dorsal portion, and the
right side portion are viewable in the front elevation, and
cooperatively define the exterior surface. The dorsal portion is
centered about the lateral centerline of the helmet in the front
and back elevation. It is appreciated that the padding 16 may
comprise a plurality of components differing in constituency,
shape, performance, function, and/or location relative to the head
of the user. The element 12 may take any suitable form, including
wire formations (FIG. 1), wherein the term "wire" is meant to
encompass a range of tensile geometric forms such as strands,
strips, bands, cables, thin sheets or slabs, etc. Upon unloading at
temperatures above the Austenitic finish temperature (Af), the SMA
will revert to the original shape (almost indefinitely), exhibiting
pseudoelastic behavior.
[0040] As best shown in FIGS. 2 and 2a, the element 12 may further
present an extendable active mesh or continuous planar sheet. In
this configuration, the mesh 12 is formed by interconnected folded
or sinuous wires 20 that where receiving an increasing normal load
are caused to mechanically deform and straighten under Austenitic
elastic behavior, to transform to the Martensite phase, to further
straighten under Martensitic elastic behavior, and then to exhibit
up to 8% strain in the Martensite phase. More preferably, a
continuous sheet of the active material element 12 is used (FIG.
2a), so as to increase the energy dissipating capability of the
helmet 10. Where superelastic SMA is used within its bounds, it is
appreciated that unloading the helmet 10 results in a reversion of
the element 12 to the Austenite phase and its original shape, or an
attempt to do the same.
[0041] As shown in FIGS. 1, 2, 2a, 4, and 6-11, energy dissipation
may be provided by, and the element 12 may be disposed within the
rigid outer shell 14, and may co-extend with the shell 14 or be
limited to that part or section of the shell 14 most anticipated to
receive an impact that may cause injury due to energy transfer.
Where limited, the helmet 10 thus defines energy dissipating and
non-active sections or parts 22,24. The non-active section(s) 24 is
otherwise conventionally structured and functional (and will not be
further discussed herein). It is appreciated that the compliant
energy dissipating section 22 dissipates at least a portion of
energy and achieves an impact condition, when receiving the
anticipatory impact, while the non-active section 24 does not
dissipate the same portion of energy and does not achieve the same
impact condition, when receiving the same anticipatory impact.
Thus, it is appreciated by those of ordinary skill in the art that
the energy dissipating section 22 and non-active section(s) 24 are
cooperatively configured such that the energy dissipating section
22, as further described herein, undergoes a greater amount of
deformation than does the non-active section(s) 24 when each
section receives the same anticipatory impact. For example, the
shell 14 of a football helmet 10 may present a dorsal energy
dissipating section 22 (as shown in FIGS. 1-3, and 10), a baseball
helmet 10 may present side energy dissipating sections 22 (FIG. 7),
a hockey helmet may present front and back energy dissipating
sections 22 (FIG. 8), a construction hard hat 10 may present a top
energy dissipating section 22 (FIG. 9); and a bicycle or motorcycle
helmet 20 may present energy dissipation over its entire exterior
surface (FIGS. 6,10). Thus, in differing applications, the energy
dissipating section 22 may co-extend with the entire exterior
surface defined by the shell 14, may co-extend within the entirety
of the dorsal portion (or other portions), or may extend within a
predetermined area of the (e.g., dorsal or side) portion wherein
the remainder of the portion presents a non-active section(s).
[0042] As shown in FIGS. 1, and 2, the preferred energy dissipating
section 22 may be laterally centered within the dorsal portion of
the shell 14, and spaced from the facemask opening in the front
elevation (FIG. 1), and/or bottom edge of the shell 14 in the back
elevation (FIG. 3), such that the dorsal portion presents
non-active distal section. For example, the dissipating section 22
may be spaced a minimum longitudinal dimension (e.g., not less than
1 inch as exemplarily shown), in the front and/or rear elevation.
It is appreciated that the non-active distal sections of the dorsal
portion interconnect the non-active side sections 24, which
increases the structural integrity (e.g., torsional strength) of
the shell 14, and enables the facemask 18 to fasten to the lesser
compliant and more durable non-active section (FIG. 1). The
dissipating section 22 may be defined in the front elevation (FIG.
1, 1b, 3), the back elevation (FIG. 2, 11), or in both elevations,
wherein the crown is (FIG. 1a) or is not traversed.
[0043] As shown in the illustrated embodiments, the dissipating
section 22 may present a variable width as it extends along its
longitudinal dimension. The dissipating section 22 may increase in
width as it approaches its distal ends in the front and/or back
elevations (FIGS. 1,2), such that it is narrowest at the apex or
crown, and widest at the distal ends (so as to increase the area of
energy dissipation in the areas adjacent the forehead and back of
the head). In this configuration, where the shell 14 presents an
overall width of approximately 10 inches and height of 12 inches,
the dorsal portion and dissipating section 22 may present a minimum
width, W1 (e.g., 4 inches) at the apex or crown (FIG. 1) and a
maximum width (e.g., W3) at curvilinear ends. The minimum width,
W1, results in an increased height, H1 (e.g., 11.5 inches or 96% of
the maximum shell height), for the deflective, non-active side
sections 24.
[0044] As shown in FIGS. 3, and 6-11, and appreciated by one of
ordinary skill in the art, the left side portion, the right side
portion, and the dorsal portion of the shell 14 may be integrally
formed such that the shell presents a unitary and non-modular
structure. That is to say, the shell 14 may present a singular body
(e.g., a curvilinear layer of injected molded hard plastic) that
defines both the dissipating section(s) 22 and non-active
section(s) 24. Here, for example, the shell 14 may be thinner, and
more preferably, at least 75% thinner (as exemplarily shown in the
illustrated embodiments), in the dissipating section than in the
non-active sections. Alternatively, the energy dissipating and
non-active sections 22,24 may be facilely and reversibly
disconnectable, so as to define separate inter-engaged parts and a
seam therebetween. In this configuration, it is appreciated that
the separate sections 22,24 are cooperatively configured to form
the shell 14, and may be formed of mated parts (e.g., wherein the
non-active section(s) define a space or depression in the shape of
the dissipating section(s), such that the dissipating section is
placed into the space and continues the layer)(FIGS. 1,2). It is
further appreciated that the separate sections are relatively
translatable when disconnected or disengaged. Finally, it is
appreciated that the separate sections 22,24 may cooperatively
define the continuous exterior surface, wherein the term "a"
continuous surface includes plural continuous surfaces (e.g., a
continuous exterior surface defined by each section). For example,
the energy dissipating and non-active sections 22,24 may be
selectively inter-engaged by a plurality of retractable pins or
dowels 26 (FIGS. 1-2). In this configuration, the pins 26 may be
(e.g., spring) biased towards the extended conditions shown, but
manually retracted into receptacles defined by the other of the
sections 22,24 when disassembly is desired. Thus, the dissipating
section 22 and the nonactive sections 24 may cooperatively include
at least one male member (e.g., pin) and at least one orifice
defined by the receptacles and be interconnected by inserting said
at least one male member into said at least one orifice. Suitable
linkage, transmission, and/or other means to effect retraction are
readily discerned by those of ordinary skill in the art and may
include a lever and bar linkage system. It is appreciated that
disassembly may be performed to repair or replace the energy
dissipating section 22. As such, where shape memory alloy is
employed, the helmet 10 is structurally configured such that
anticipatory impacts are able to transfer sufficient loading to the
element 12 to cause it to activate (e.g., transform fully from
Austenite to Martensite phase) without disassembly or failure of
the helmet 10. For example, it is appreciated that a 200 MPa stress
and 5% strain will spontaneously transform mean Austenitic SMA to
Martensitic SMA, where it will then be able to undergo further
strain, exhibiting superelastic behavior.
[0045] In another aspect of the invention, the energy dissipating
section 22 may be further formed of a material operable to
facilitate repair, such as a shape memory polymer (SMP). That is to
say, it is certainly within the ambit of the present invention for
the energy dissipating section 22 to comprise SMP so as to
facilitate repair, whereas energy absorption is accomplished
conventionally and the assembly 10 is devoid of a stress-activated
active material (e.g., SMA). More particularly, energy dissipation
may be provided through the deformation of known mechanical means,
such as tapered thin-walled structures, honeycomb structures,
recoverable (semi-rigid) foams, and other types of energy
absorption mechanisms as further described herein. To that end, it
is appreciated that the greater deformation of the shell itself in
the dissipating section 22 imparts a quantum of energy dissipation.
In this configuration, the SMP constituent material provides the
section 22 with the ability to remember and achieve its original
shape simply by heating the polymer past its activation temperature
(e.g., glass transition temperature range). As is appreciated by
those of ordinary skill in the art, thermally-activated shape
memory polymers (SMP's) generally refer to a group of polymeric
active materials that demonstrate the ability to return to a
previously defined shape when subjected to an appropriate thermal
stimulus. Their elastic modulus changes substantially (usually by
one--three orders of magnitude) across a narrow transition
temperature range, which can be adjusted to lie within a wide range
that includes the interval 0 to 150.degree. C. by varying the
composition of the polymer.
[0046] Generally, SMP's have two main segments, a hard segment and
a soft segment. The previously defined or permanent shape can be
set by melting or processing the polymer at a temperature higher
than the highest thermal transition followed by cooling below that
thermal transition temperature. The highest thermal transition is
usually the glass transition temperature (T.sub.g) or melting point
of the hard segment. A temporary shape can be set by heating the
material to a temperature higher than the T.sub.g or the transition
temperature of the soft segment, but lower than the T.sub.g or
melting point of the hard segment. The temporary shape is set while
processing the material above the transition temperature of the
soft segment followed by cooling to fix the shape. The material can
be reverted back to the permanent shape by heating the material
above the transition temperature of the soft segment.
[0047] More particularly, where the rigid outer shell 14 is formed
of a thin layer of SMP (having an Austenitic SMA mesh or sheet 12
disposed therein), and caused to be permanently deformed (i.e.,
inelastically deformed) by the impact as shown in FIG. 3, it may be
repaired simply by unloading and heating the section 22 past the
glass transition temperature of its soft segment in order to
achieve the original shape (FIG. 1). In a football setting, for
example, a deformed energy dissipating section 22 (FIG. 3) may be
removed from the helmet 10, passed through a heater or oven,
allowed to cool, and then reassembled on the sideline.
Alternatively, it is appreciated that a hand-held heater (e.g.,
blow dryer) may be used to heat the shell 14. Here, the shell 14
and the return force of the element 12 may be cooperatively
configured so as to manipulate the SMP only when the SMP is in its
more malleable state.
[0048] Though it is appreciated that Austenitic SMA provides a
two-way effect when deactivated, a return element 28 may compose
the energy dissipating section 22, so as to aid in its return to
its original shape and appearance. For example, as shown in FIG. 2,
a return mesh 28 (e.g., formed of elastic fibers or sheaths) may be
interposed with the active mesh 12 to drive both the return of the
active mesh 12 to a more folded or compressed state once extended,
and the dissipating section 22 to its original shape when deformed.
It is appreciated that, the return mesh 28 adds to the structural
integrity of the shell 14.
[0049] In another embodiment, the dissipating section 22 may be
presented by a composite shell 14 that is formed by inner and outer
layers 30,32 spaced by a collapsible medium 34 or fluid (e.g.,
air). Here, the entire outer layer 30 presents the dissipating
section 22, while the inner layer presents a hard conventional
shell that does not deform or crumple under the impact. The outer
layer 30 is preferably formed of a compliant yet durable material,
and as such, may be formed of a thinner layer of hard plastic,
metal, carbon fiber, composites, or the like, in comparison to the
conventional inner layer 32 (FIGS. 2a, 4,4a, 4d). That is to say,
the outer layer 30 may present a first thickness, and the inner
layer 32 presents a second thickness greater than the first
thickness.
[0050] In a preferred embodiment, air (or other fluid) interposed
between the layers 30,32 and through-holes 31 (FIG. 1b) defined by
the outer layer 30 may function to facilitate or allow the outer
layer 30 to resistively collapse towards the head and inner layer
32 during impact (FIG. 2a). The suffix "(s)" as used herein is
intended to include both the singular and the plural of the term
that it modifies, thereby including one or more of that term. As
such, it is appreciated that the dissipating section 22 may utilize
one or more through-holes to accomplish this function. The shape
and exact positioning of the through-hole(s) 31 may vary. In FIG.
1b, a U-shaped through-hole (or cutout) 31 is laterally centered
within the dorsal portion in the front elevation to define a
foldable flap that resistively collapses towards the head upon
impact. As such, the dissipating section 22 may further present a
fold-line 35 at the base of a flap having lateral slopes, since
that is whereabout the greatest moment will act upon the flap. It
is appreciated that fold-lines may be further etched or pinched
into the layer to promote folding. It is also appreciated that the
dissipating section(s) 22 may employ multiple fold-lines to
resistively collapse in a concertinaed fashion.
[0051] Where SMA is employed, the spacing is configured to allow
the element to achieve up to 8% strain. For example, and as shown
in FIG. 1-3, a football helmet 10 may present a raised dorsal
energy dissipating section 22 comprising inner and outer layers
30,32 spaced by air, wherein the outer layer 30 is formed of SMP
and includes an Austenitic SMA sheet 12 disposed within the neutral
axis of the SMP. It is appreciated that the collapsed or crumpled
state of the outer layer 30 provides a visual indication that the
helmet 10 has properly functioned to dissipate energy (FIG. 3). It
is further appreciated that the SMP outer layer 30 may be used
without the use of SMA in the remainder of the helmet, such that
energy dissipation is performed solely by the "crumpling" action of
the outer layer 30. Thus, the present invention contemplates energy
dissipating through deformation of the shell itself, wherein the
energy dissipating section 22 is devoid of and energy is not
dissipated by an external attachment, and wherein the energy
dissipating section 22 is devoid of and the energy is not
dissipated by an internal element disposed intermediate the shell
14 and user.
[0052] It is yet further appreciated that the outer layer 30 may be
geometrically configured to facilitate crumpling, and more
preferably, to control deformation under impact. For example, the
dissipating section 22 may present lateral slopes that distend from
a general fold in a dorsal application, so as to deter purely
dorsal impacts (FIG. 1b). Thus, the energy dissipating section 22
and non-active section(s) 24 are cooperatively configured such that
the energy dissipating section 22 undergoes a greater amount of
deformation than does the non-active section(s) 24 when each
section receives an anticipatory impact. Finally, it is appreciated
that existing helmets may be retrofitted in this manner by
removably attaching (e.g., via existing screws located in the front
and rear of the helmet, etc.) or fixing an SMP outer shell to and
cooperatively defining an interior space with the existing outer
shell of the pre-existing helmet.
[0053] In lieu of air, a compressible or viscous medium 34 may be
interposed between the layers 30,32 to provide further energy
absorption. Where the composite shell further includes a
compressible medium 34 interposed between the inner and outer
layers 30,32, the medium functions to cause the outer layer to
resistively collapse towards the inner layer and provide a return
mechanism that drives the outer layer back towards the non-impacted
condition. The medium 34 may be formed at least in part by the
active material element 12 (FIG. 4) to provide further energy
dissipation. For example, the medium 34 may define a
cross-sectional cellular matrix formed of Austenitic SMA, such as
the honeycomb pattern shown in FIG. 4. In this configuration, the
outer layer 30 and medium 34 are collapsible by the impact and
configured to locally deform under the loading of the impact. Here,
the outer layer 30 may be formed of an even more compliant
material, such as leather, or a vinyl sheet fixedly adhered to the
medium 34, since resistive collapse is provided by the medium 34.
As previously described, the outer layer 30 may further include an
Austenitic SMA mesh 12 for added energy dissipation (FIG. 4). In
this configuration, the return element 28 may consist of tubular
elastic members positioned within cell of the matrix 34, or a
plurality of compression springs drivenly coupled and orthogonally
oriented relative to the engaging surface of the medium 34
(preferably at nodes or vertices defined thereby). That is to say,
a plurality of tubular elastic members or compression springs 28
may be drivenly coupled to the outside surface of the inner layer
32 and the inside surface of the outer layer 30 (i.e., the medium
engaging surfaces), so as to drive the outer layer 30 towards the
pre-impact condition (FIG. 4d). It is appreciated that overcoming
this bias (i.e., the elastic modulus of the members or the spring
stiffness) further functions to dissipate energy during the impact.
Accordingly, the members or springs 28 are sized and spaced based
on the anticipatory impact.
[0054] Alternatively, the medium 34 may include a plurality of
hollow Austenitic SMA spheres or capsules 12, each collapsible by
the impact (FIG. 4a). The spheres 12 are preferably confined so as
to prevent migration and maximize the conversion of impact energy
to sphere deformation. To aid in this, the medium 34 may be
bifurcated and supported by collapsible sectioning walls 36 (FIGS.
4 and 4a). That is to say, the medium 34 may be confined in by a
plurality of separate compartments, so as to promote local
deformation. In yet another alternative, the medium 34 may further
include a compressible substrate 38, wherein the spheres 12 are
fixedly embedded (FIG. 4a).
[0055] As previously mentioned, the active material element 12 may
compose the compressible interior padding 16, so as to provide
energy dissipation from within the shell 14. As shown in FIG. 1,
for example, pre-existing padding 16 may be retrofitted by
entraining Austenitic SMA wire 12a within otherwise non-active
cushion material (i.e., "cushion") 40. Individual wire passes may
be stand-alone or intertwined to form a geometric shape, webbing,
or mesh. The wires 12a are fixedly anchored to the shell 14 through
reinforced connection able to withstand the maximum tensile loads
experienced thereby. The wires 12a may be attached to the shell 14
prior to placing the padding 16. The existing padding 16 may be
caused to define narrow cutouts (not shown) (e.g., through laser
etching, etc.) that match the configuration of the wires 12a, so as
to depose the wires 12a at a predetermined depth within the cushion
material 40.
[0056] The wire(s) 12a are preferably pre-strained so as to
eliminate slack and produce a more instantaneous response. That is
to say, when an anticipatory impact strikes the helmet 10 and the
head of the user is caused to compress the padding 16, the
preferred wire(s) 12a will be immediately caused to stretch,
thereby invoking a tensile stress operable to trigger
transformation to the more malleable Martensite phase. Once
transformed, it is appreciated that the Martensite wire 12a will be
further able to strain up to 8%. The padding 16 and wire(s) 12a are
cooperatively configured such that the wires 12a do not interfere
with the function of the padding 16, and the wires 12a are able to
completely transform and achieve their maximum strain. More
preferably, the cushion material 40 and wires 12a are cooperatively
configured such that the impact causes the cushion material 40 to
partially compress prior to transforming the wires 12a, and then
further compress after the wires 12a have been fully transformed
and strained.
[0057] In another embodiment, the interior padding 16 may include
conventional non-active cushion material 40 and an active material
layer 12 disposed intermediate and secured (e.g., fastened,
coupled, adhesively bonded, etc.) to the shell 14 and/or cushion
material 40 (FIGS. 4, 4b, and 4c). In this configuration,
deformation of the active material layer 12 occurs from within the
shell 14, as the head of the user bears upon the layer 12, during
impact. In a first example, the layer 12 may present a thin planar
Austenitic SMA sheet defining contours to match the cushion 40,
wherein the layer 12 is spaced from the rigid outer shell 14,
except, for example, at coupling supports (not shown), so as to
generally enable the sheet 12 to strain and transform under the
load. Alternatively, and as shown in FIG. 4c, an Austenitic SMA
sheet defining polygonal faces 12b and vertices 12c may be
intermediately placed between the shell 14 and cushion material 40,
such that the faces 12b and not the vertices 12c are spaced from
the shell 14. Means for preventing lateral migration by the layer
12, e.g., by fastening to the shell 14 near or along the edges of
the layer 12 is necessarily provided, so as to effect the intended
strain during impact. For example, cushion fasteners (not shown)
may simply pass through the layer 12 thereby further anchoring the
layer 12. In operation, the geometry of the polygons and shell 14
will produce the spacing necessary adjacent the faces 12b. It is
appreciated that where an impact causes the head of the user to
bear upon a face 12b (through the cushion 40), the sheet 12 will be
caused to locally transform and bow, thereby encroaching the
adjacent space, achieving superjacent layers with the shell 14 and
cushion 40, and exhibiting up to 8% strain. Thus, during an impact,
the layer 12 will dissipate energy through mechanical deformed in a
break-away manner, and through the phase transformation of the SMA
triggered by the stress incurred in the material as it bears the
load. To facilitate implementation, the preferred sheet or layer 12
is facilely compliant along the edges of the polygons (e.g., via
etched fold lines), so as to generally achieve the contours of
various conventional shell geometries (FIG. 4c) and expand its
retrofitting/reconditioning capability. Moreover, it is appreciated
that the layer 12 may be caused to achieve its more compliant
Martensitic phase prior to assembly by lowering its temperature
past the transformation temperature range.
[0058] In another embodiment, an active compressible layer (e.g.,
cellular matrix) may co-extend, so as to form supejacent layers
with the entire interior surface of the shell 14 (FIG. 4b), or may
be positioned only within energy dissipation sections 22, so as to
reduce weight. In a first example, a compliant spring-mattress type
layer 12 comprising energy-absorbing coils as further described
below, may be positioned intermediate the interior surface of the
shell 14 and non-active cushion material 40. In this configuration,
the cushion material 40 defines at least one cutout 42, so as to
form an enclosed cavity, and the element 12 presents at least one,
and more preferably a plurality of compressible Austenitic SMA
springs or coils disposed within each cutout 42 (FIG. 4). The
cutout 42 is configured such that facilely compressible walls 44
about the cavity are created. This allows the majority of the
compression force to act upon the springs 12. The springs 12 are
configured such that compressive force necessary to generate the
activation stress is not less than, and more preferably equal to
the force necessary to compress the springs 12 in the Austenitic
phase, so that compression and transformation occur
contemporaneously or transformation lags partial compression. The
spring geometry and SMA constituency may be cooperatively
configured such that the springs 12, in their Austenite phase,
present a spring modulus generally equivalent to the compressive
force of conventional cushion material 40. As such, it is
appreciated that the number of turns, pitch, and diameter of the
spring wire shown in FIG. 4 may not reflect the preferred
embodiment of the invention.
[0059] Once transformation occurs, it is appreciated that the
springs 12 will more readily compress under the lower spring
modulus afforded by the Martensitic SMA and reduced cross-section
of the walls 44 in comparison to conventional cushion material 40.
Therefore, the preferred cushion material 40 presents enough volume
to further compress after the springs 12 fully compress (FIG. 4).
Alternatively, each active spring 12 may be connected in series to
a conventional spring 46 presenting a higher modulus than the
Martensitic spring 12, but comparable to the cushion material 40,
so as to provide further compression after transformation where
needed (FIG. 5). Thus, while the performance and compressibility of
conventional interior padding may be maintained, the total amount
of energy absorption/dissipation, under the present invention, is
increased due to transforming the phase of the SMA material in
addition to conventional mechanical deformation.
[0060] In addition to energy dissipation, the entire assembly 10 is
preferably operable to provide structural integrity, and comfort at
least on par with those of conventional helmets. Finally, in either
configuration, it is appreciated that the inventive helmet 10 may
be configured to provide energy dissipation (e.g., undergo an SMA
stress-activated phase transformation) when encountering a maximum,
mean, or minimum anticipatory impact, wherein the term "maximum"
shall define the limit of those impacts deemed safe for the user to
endure without the intended benefits of the present invention, so
that energy dissipation (e.g., SMA actuation cycle) is triggered
only in excessive impact occurrences, and the term "minimum" shall
mean any impact within the range of anticipatory impacts, so that
energy dissipation is triggered by all anticipatory impacts.
[0061] In yet another embodiment of the invention, it is
appreciated that piezoelectric ceramics/composites 12, preferably
composing the outer shell 14, may be used to convert a change in
pressure into electricity that is then dissipated through resistive
elements 48 as heat, and/or through luminaries (e.g., LED's) 50 as
light, wherein the resistive elements 48 and/or luminaries 50
compose the helmet 10 (FIG. 11). The lights may also serve to alert
interested parties that the user has sustained an impact to the
head, which, for example, in a football setting, may be used to
teach proper tackling technique. It is appreciated that the
piezoelectric activation may be used to drive an audible alert in
addition to or lieu of a visual alert.
[0062] Piezoelectric ceramics include PZN, PLZT, and PNZT. PZN
ceramic materials are zinc-modified, lead niobate compositions that
exhibit electrostrictive or relaxor behavior when non-linear strain
occurs. The relaxor piezoelectric ceramic materials exhibit a
high-dielectric constant over a range of temperatures during the
transition from the ferroelectric phase to the paraelectric phase.
PLZT piezoelectric ceramics were developed for moderate power
applications, but can also be used in ultrasonic applications. PLZT
materials are formed by adding lanthanum ions to a PZT composition.
PNZT ceramic materials are formed by adding niobium ions to a PZT
composition. PNZT ceramic materials are applied in high-sensitivity
applications such as hydrophones, sounders and loudspeakers.
[0063] Piezoelectric ceramics include quartz, which is available in
mined-mineral form and man-made fused quartz forms. Fused quartz is
a high-purity, crystalline form of silica used in specialized
applications such as semiconductor wafer boats, furnace tubes, bell
jars or quartzware, silicon melt crucibles, high-performance
materials, and high-temperature products. Piezoelectric ceramics
such as single-crystal quartz are also available.
[0064] The preferred forms of the invention described above are to
be used as illustration only and should not be utilized in a
limiting sense in interpreting the scope of the present invention.
Obvious modifications to the exemplary embodiments and methods of
operation, as set forth herein, could be readily made by those
skilled in the art without departing from the spirit of the present
invention. The inventor hereby states his intent to rely on the
Doctrine of Equivalents to determine and assess the reasonably fair
scope of the present invention as pertains to any system or method
not materially departing from but outside the literal scope of the
invention as set forth in the following claims.
[0065] Additionally, the terms "a" and "an" herein do not denote a
limitation of quantity, but rather denote the presence of at least
one of the referenced item. The suffix "(s)" as used herein is
intended to include both the singular and the plural of the term
that it modifies, thereby including one or more of that term.
Reference throughout the specification to "one embodiment",
"another embodiment", "an embodiment", and so forth, means that a
particular element (e.g., feature, structure, and/or
characteristic) described in connection with the embodiment is
included in at least one embodiment described herein, and may or
may not be present in other embodiments. It is to be understood
that the described elements may be combined in any suitable manner
in the various embodiments.
* * * * *