U.S. patent application number 12/999004 was filed with the patent office on 2011-05-12 for compressible liner for impact protection.
Invention is credited to Donald Edward Morgan.
Application Number | 20110107503 12/999004 |
Document ID | / |
Family ID | 41463207 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110107503 |
Kind Code |
A1 |
Morgan; Donald Edward |
May 12, 2011 |
Compressible Liner for Impact Protection
Abstract
A compressible liner for impact protection, which may be
installed in a helmet worn by a person. The compressible liner may
also be applied to other impact protection situations, for example
to baby capsules and child safety seats, as well as offering
customised zones of impact protection. The compressible liner may
have a relatively low density foam inner layer fused to a
relatively high density foam outer layer. The inner layer may have
many cone shaped protuberances which project into matching recesses
of the outer layer. The compressible liner provides an initial low
resistance to the impact for a desired part of the human body. As
the impact progresses the level of resistance provided by the
compressible liner increases in a controlled manner so that
controlled deceleration of the part of the body is occurring
throughout the impact for a desired impact protection zone of the
compressible liner.
Inventors: |
Morgan; Donald Edward;
(Queensland, AU) |
Family ID: |
41463207 |
Appl. No.: |
12/999004 |
Filed: |
July 2, 2009 |
PCT Filed: |
July 2, 2009 |
PCT NO: |
PCT/IB2009/006133 |
371 Date: |
December 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12166447 |
Jul 2, 2008 |
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12999004 |
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Current U.S.
Class: |
2/456 ;
2/411 |
Current CPC
Class: |
F41H 1/08 20130101; A42B
3/128 20130101; A42B 3/124 20130101 |
Class at
Publication: |
2/456 ;
2/411 |
International
Class: |
A41D 13/00 20060101
A41D013/00; A42B 3/06 20060101 A42B003/06 |
Claims
1. An apparatus for impact protection for at least a part of a
human body comprising: a compressible liner with an inner layer and
an outer layer, wherein the inner layer has a contact surface and a
first joining surface, wherein the first joining surface includes a
plurality of protuberances; wherein the outer layer has a second
joining surface and an outer surface, wherein the second joining
surface includes a plurality of recesses adapted to receive the
protuberances of the inner layer; wherein the inner layer includes
a first material of a first compressibility and the outer layer
includes a second material of a second compressibility; and wherein
the first compressibility is greater than the second
compressibility.
2. An apparatus according to claim 1, wherein: at least part of the
contact surface of the inner layer of the compressible liner is
adapted to be immediately adjacent or to engage with part of the
human body.
3. An apparatus according to claim 1, wherein: the protuberances
are conical.
4. An apparatus according to claim 1, wherein: said inner layer is
formed from one or more inner layer segments.
5. An apparatus according to claim 4, wherein: the first
compressibility is different between one or more inner layer
segments.
6. An apparatus according to claim 1, wherein: said outer layer is
formed from one or more outer layer segments.
7. An apparatus according to claim 6, wherein: the second
compressibility is different between one or more outer layer
segments.
8. An apparatus according to claim 1, wherein: one or more of the
first material and the second material are foam.
9. An apparatus according to claim 8, wherein: said foam includes
expanded polystyrene.
10. An apparatus according to claim 9, wherein: the first material
has a density in the range of 15 to 50 kgm.sup.-3.
11. An apparatus according to claim 10, wherein: the first material
has a density in the range of 25 to 35 kgm.sup.-3 and the second
material has a density in the range of 35 to 50 kgm.sup.-3.
12. An apparatus according to claim 10, wherein: the first material
has a density in the range of 15 to 25 kgm.sup.-3 and the second
material has a density in the range of 35 to 45 kgm.sup.-3.
13. An apparatus according to claim 9, wherein: the second material
has a density in the range of 35 to 90 kgm.sup.-3.
14. An apparatus according to claim 13, wherein: the second
material has a density in the range of 35 to 55 kgm.sup.-3.
15. An apparatus according to claim 1, wherein: one or more of the
first material and the second material are viscoelastic or
thixotropic.
16. An apparatus according to claim 1, wherein: a penetration of
one or more protuberances into the outer layer is in the range of
50 to 100%.
17. An apparatus according to claim 1, wherein: an apex of one or
more protuberances is contiguous with the outer surface.
18. An apparatus according to claim 1, wherein: the distance
between adjacent bases of the protuberances is in the range of 0 to
20 mm.
19. An apparatus according to claim 18, wherein: the distance
between adjacent bases of the protuberances is in the range of 5 to
15 mm.
20. An apparatus according to claim 1, wherein: the maximum
transverse dimension of a base of the protuberances is in the range
of 15 to 22 mm.
21. An apparatus according to claim 1, wherein: the compressible
liner has a thickness in the range of 15 to 45 mm; a height of one
or more protuberances from the base of the respective protuberance
is in the range of 20 to 25 mm; and a distance from the base of one
or more protuberances to the contact surface is in the range of 5
to 10 mm.
22. An apparatus according to claim 1, wherein: the inner layer is
visible through the outer layer.
23. An apparatus according to claim 1, wherein: the compressible
liner comprises a removable and replaceable fitting.
24. An apparatus according to claim 1, wherein: one of the inner
and outer layer comprises a strip from which a line of
protuberances project.
25. An apparatus according to claim 24, wherein: said layer is the
inner layer.
26. An apparatus according to claim 24, wherein: a plurality of
said strips are connected to the compressible liner so as to form a
one-piece component.
27. An apparatus according to claim 1, wherein: the compressible
liner is installed within or forms an article selected from the
group including: a vehicle cabin liner, a baby capsule, a child
safety seat, a seat, a head rest and a body armour.
28. An apparatus according to claim 1, wherein: the compressible
liner is installed within or forms a helmet.
29. A method of impact protection for at least a part of the human
body by providing apparatus having: an initial low resistance to an
impact to at least a part of a human body; and then progressively
increasing the level of resistance to the impact to at least a part
of the human body as the impact progresses.
30. An apparatus for impact protection of at least part of an
article, the apparatus comprising: a compressible inner with a
stiffness gradient; wherein the stiffness gradient during an impact
varies from a low stiffness adjacent to the article to a higher
stiffness through the thickness of the compressible liner.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and a method
for improved impact protection using a compressible liner.
[0003] 2. Description of the Art
[0004] Applicant was co-author of a study titled "Improved Shock
Absorbing Liner for Helmets", Australian Transport Safety Bureau
(ATSB), www.atsb.gov.au, published in July, 2001. In that
publication, a combination of low density foam embedded into high
density foam was disclosed as one subject of the study. However,
the study did not contemplate or discuss the combination of
structural elements or method disclosed herein.
[0005] Past research has shown that common single density foam
liners used in current helmets are too hard and too stiff to
effectively absorb an impact force. A single density foam liner is
also limited in its ability to accommodate the variation in
strength about the human skull. In addition liners in bicycle
helmets for children use liners designed for adult skulls, they do
not account for a child's more deformable skull in comparison to an
adult. The more deformable skull of a child is less protective of
the brain. Incorporated by way of reference is: Corner et al,
"Motorcycle and Bicycle Protective Helmets--Requirement Resulting
from a Post Crash Study and Experimental Research", Report No. CR
55, 1987, Federal Office of Road Safety, Canberra, Australia and
Mohan et al; and "A Biomechanical Analysis of Head Impact Injuries
to Children" Vol. 101, 1979, Transactions of the ASME, Journal of
Biomechanical Engineering.
[0006] In addition the brain is also susceptible to impact injury
against the inside of the skull. The brain is a jelly like soft
tissue suspended within the enclosure of the hard skull in a bath
of cerebral spinal fluid. Additionally the brain is flexibly
supported within the skull by the brain stem and spinal cord at the
base of the brain, whilst about the general outer periphery of the
brain the dura-mater membrane connects the brain to the skull at
various suture points. An impact to the travelling skull may cause
the skull to rapidly decelerate whilst the flexibly supported brain
continues to travel and impact against the inside of the skull. The
impact of the brain against the skull may cause contusions and/or
haemorrhaging to the brain. Thus it may be important to decelerate
the head appropriately to minimise internal injuries.
[0007] Bone tests for the human skull have indicated that the
temporal portion of the skull has a significantly reduced bone
strength compared with other portions of the skull. Consequently
the temporal portion of the skull is more vulnerable to impact
injury compared with other portions of the skull. However, current
helmets are not manufactured with a compressible liner to provide
different zones of impact protection about the skull.
[0008] Similarly for other application areas for impact protection
such as baby capsules and child safety seats for passenger
vehicles, vehicle cabin liners and body armour there are profound
deficits in the provision of different zones of impact protection
about the human body. The word "baby capsule" in the specification
and the claims is taken to include one or more of rear facing
infant or baby seats for the seat of a car, reclining rear facing
seats for an infant or a baby and seats or capsules for children up
to approximately 1 year of age. The word "child safety seat" in the
specification and the claims is taken to include one or more of
forward facing toddler seats, toddler seats in general, seating for
children up to approximately 4 years of age, booster
seats/cushions, seats without a backrest and seating in general for
children for approximate ages of 4 to 8 years of age. Booster seats
may be described as seats without a backrest that are designed so
as to raise the seating position of the child so that the sash of
the existing adult lap-sash seatbelt appropriately engages the
child's shoulder and chest. Toddler seats may be differentiated
from booster seats in that they may have an independent five point
harness to secure the child to the toddler seat, the toddler seat
then being secured to the existing seat or other attachments points
within a car or other vehicle.
[0009] Baby capsules and child safety seats may have protective
side panels or thigh, torso and head bolsters (or projections or
"wings") on the sides of the baby capsule or child safety seats.
These side panels or bolsters serve to limit the amount of sideways
movement that a baby or child may experience in a side impact. They
may also serve to protect the baby or child from impact of a side
air bag in the event that the air bag is triggered in a collision.
In other terminology the protective side panels may form a
protective "channel" about the baby or child.
[0010] Baby capsules and child safety seats typically do not
differentiate between the head and the torso of the baby or child
in terms of the level of impact protection required. A rear facing
baby capsule for a car may be lined with a single density foam
liner sufficient to provide impact protection to the baby
externally as a whole, but may be insufficient to prevent
contusions and/or haemorrhaging to the back of the baby's brain in
the event of a head on collision by the car.
[0011] Child safety seats that are typically used for children
above an approximate age of one year are commonly constructed of or
have liners of polystyrene foam which may be as hard or harder than
typical single density polystyrene foam liners used in helmets for
adults. Such low compressibility (high stiffness) polystyrene foams
do not provide adequate impact protection for children since they
are too hard. Child safety seats may also be augmented with a thick
liner or structure of a very compressible upholstery or cushioning
foam which is so soft and pliable as to provide minimal or nil
impact protection to a child. The purpose of such upholstery or
cushioning foam liners or structures is primarily for comfort and
appearance.
[0012] None of the prior art provides and entirely satisfactory
solution to the problem of providing different levels of
appropriate impact protection for the head or to other parts of the
body, nor to the ease of manufacture to obtain a more satisfactory
impact protection with a compressible liner.
SUMMARY OF THE INVENTION
[0013] The present invention aims to provide embodiments of a
compressible liner for impact protection which overcome or
ameliorate the disadvantages of the prior art.
[0014] In one form, the invention provides a compressible liner for
impact protection for at least part of a human body. The
compressible liner includes: an inner layer and an outer layer,
where the inner layer has a contact surface and a first joining
surface with a plurality of protuberances. The outer layer has a
second joining surface and an outer surface, where the second
joining surface includes a plurality of recesses which are adapted
to receive the protuberances of the inner layer. Additionally the
inner layer includes a first material of a first compressibility
and the outer layer includes a second material of a second
compressibility; preferably the first compressibility being greater
than the second compressibility. The contact surface of the inner
layer of the compressible liner is adapted to be adjacent or engage
with part of the human body.
[0015] Preferably the protuberances are conical. The compressible
liner of the invention may be installed within or form for example,
a vehicle cabin liner, a baby capsule, a child safety seat, a seat,
a head rest or body armour. Preferably, in all applications, the
compressible liner may be a removable and replaceable fitting
[0016] Optionally the compressible liner may be formed from one or
more inner or outer layer segments and the compressibility between
the respective layer segments may differ.
[0017] Optionally one or more of the materials forming the
compressible liner may be foam, preferably Expanded Polystyrene
(EPS). Alternatively one or more of the materials may be
viscoelastic. Preferably the densities of the EPS foam materials
may be: [0018] The inner layer may have a density in the range of
15 to 50 kgm.sup.-3. [0019] The outer layer may have a density in
the range of 35 to 90 kgm.sup.-3 or more preferably a density in
the range of 35 to 55 kgm.sup.-3. [0020] The inner layer may have a
density in the range of 25 to 35 kgm.sup.-3 and outer layer may
have a density in the range of 35 to 50 kgm.sup.-3. [0021] The
inner layer may have a density in the range of 15 to 25 kgm.sup.-3
and outer layer may have a density in the range of 35 to 45
kgm.sup.-3.
[0022] Optionally the penetration of one or more protuberances from
the inner layer into the outer layer may be in the range of 50 to
100%. Preferably, an apex end of one or more protuberances is
contiguous with the outer surface.
[0023] Preferably the distance between adjacent circular bases is
in the range of 0 to 20 mm and more preferably in the range of 5 to
15 mm.
[0024] Preferably the diameter of the circular base is in the range
of 15 to 22 mm.
[0025] Optionally the compressible liner may have a thickness in
the range of 15 to 45 mm, a height of one or more protuberances
from the circular base may be in the range of 20 to 25 mm and a
distance from the circular base of one or more protuberances to the
contact surface may be in the range of 5 to 10 mm.
[0026] In a further form of the invention the inner layer is
visible through the outer layer.
[0027] In a further form the invention provides a method of impact
protection for at least a part of the human body, wherein the
method provides an initial low resistance to an impact to at least
a part of a human body and then progressively increases the level
of resistance to the impact to at least a part of the human body,
as the impact progresses.
[0028] In yet a further form, the invention provides an apparatus
for impact protection of a least a part of an article, wherein the
apparatus includes a compressible liner with a stiffness gradient.
The stiffness gradient during an impact preferably varies from a
low stiffness adjacent to the article to a higher stiffness through
the thickness of the compressible liner. `Articles` includes goods,
humans, animals or anything of value.
[0029] Further forms of the invention are as set out in the
appended claims and as apparent from the description.
DISCLOSURE OF THE INVENTION
Brief Description of the Drawings
[0030] Further preferred embodiments of the invention will now be
described with reference to the accompanying drawings, in
which:
[0031] FIG. 1 is a schematic cross-sectional view of the
compressible liner in a helmet in an embodiment of the present
invention.
[0032] FIG. 2 is a cross-sectional view taken along the line 2-2 of
FIG. 1.
[0033] FIG. 3 is a schematic, perspective, part-sectional view of
an alternate embodiment of a compressible liner in the helmet
embodiment.
[0034] FIG. 4 is an exploded view of FIG. 3.
[0035] FIG. 5 is a schematic cross-sectional view of the
compressible liner.
[0036] FIG. 6 is an alternate embodiment of the compressible liner
in FIG. 5.
[0037] FIG. 7 is a schematic cross-sectional view of the
compressible liner in a portion of a vehicle cabin, in an
embodiment of the invention.
[0038] FIG. 8 is a schematic cut-away illustration of the interior
of a civilian passenger car with an installed embodiment of the
vehicle cabin liner compressible liner of FIG. 7.
[0039] FIG. 9 schematically illustrates, in a perspective view, an
example of an embodiment of a baby compressible liner for a baby
capsule.
[0040] FIG. 10 is a schematic perspective view of a child safety
seat with a child safety seat compressible liner.
[0041] FIG. 11 is a schematic of a front elevation view of a
protective vest with inserts of a body armour compressible
liner.
[0042] FIG. 12 is a schematic cross-sectional view of a double
compressible liner, in an embodiment of the invention. FIG. 13 is a
schematic view of the inner liner in strip form.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Reference is first made to FIGS. 1 and 2 which are
orthogonal cross-sectional views, schematically showing a first
embodiment of a compressible liner 110 installed in a helmet 112
worn by a person 114. The helmet 112 may include a hard outer shell
116 against the outer surface 118 of the compressible liner 110 and
also may include a comfort liner 120 against the contact surface
122 of the compressible liner 110. If a comfort liner 120 is
present then it is appreciated that the head is immediately
adjacent the contact surface 122 via the comfort liner 120. If the
comfort liner is not present the contact surface 122 engages the
head directly.
[0044] The compressible liner 110 may have a relatively low density
foam inner layer 124 fused, adhered or otherwise attached at
respective joining surfaces 126 to a relatively high density foam
outer layer 128, where the lower density foam is more easily
compressed than the higher density foam. That is, the first
material forming the inner layer 124 is more compressible than the
second material forming the outer layer 128. The inner layer 124
has many protuberances 130 which project into matching recesses 132
of the outer layer 128 at the joining surface 126. The inner layer
124 has a first region 134 of a relatively uniform thickness layer.
Extending radially outwardly from the first region 134 is the
multiplicity of protuberances 130 integrally formed with the inner
layer 124. The protuberances 130 have apex ends 136 as well as
bases 138 having outer peripheries 140 closely spaced from bases
138 of adjacent protuberances 130. The outer peripheries 140
distance may also be considered as the closest distance between
adjacent bases 138 of the protuberances 130.
[0045] In an embodiment of the compressible liner 110 the foam
material may be expanded polystyrene foam (EPS) where the density
of the foam is commonly proportional to a compressibility or a
stiffness of the foam, where stiffness has an inverse proportional
relationship to compressibility. In a preferred embodiment, the
inner layer 124 may have a density of in the range of 20 to 50
kgm.sup.-3, (or 1.25 to 3.12 pounds per cubic foot). The outer
layer 128 may have a density of in the range of 35 to 90 kgm.sup.-3
(or 2.18 to 5.62 pounds per cubic foot) and more preferably 35 to
55 kgm.sup.-3. In all choices of the respective foam density for
the inner layer 124 and outer layer 128, the foam density of the
inner layer 124 is less than that of the outer layer 128. In a more
preferable embodiment the inner layer 124 foam density may be in
the range of 25 to 35 kgm.sup.-3 and the outer layer 128 foam
density may be in the range of 35 to 50 kgm.sup.-3. In accordance
with the teachings of the present invention, the foam employed may
be of any suitable type that permits the desired compressibility or
stiffness to be achieved as for the EPS foam embodiment given above
and below. In all instances described above and below it will be
noted that the first material forming the inner layer 124 has a
first compressibility which is more than second material forming
the outer layer 128, which has a second compressibility.
[0046] The lines 142 represent the boundaries 142 between adjacent
segments 144, 146, 148, 150 of the compressible liner 110. The
division of the compressible liner 110 into a number of segments as
illustrated in FIG. 1 allows different zones of impact protection
to be customised for the helmet 112. For example the rear segment
150 of the compressible liner 110 may be configured and constructed
to offer a higher level of impact protection than crown segment
146.
[0047] In FIG. 2 another example of the division of the
compressible liner 110 into a number of segments 210, 212, 214, 216
to provide different zones of impact protection is shown. The
temporal segments 210, 216 may be configured and constructed to
offer a higher level of impact protection compared to the crown
segments 212, 214 due to the higher level of vulnerability of the
temporal portions of the skull.
[0048] FIG. 3 is a perspective, part-sectional view of an alternate
embodiment of the compressible liner 310 with an emphasis to
illustrating the protuberances 130 of the inner layer 124. For
clarity the portion of the helmet 112 covering the ear is omitted
from FIG. 3. In the embodiment illustrated the protuberances 130
are conical with circular bases 138. In alternate embodiments the
conical protuberances may have bases 138 that are polygonal in
configuration, for example, trigonal, square, pentagonal,
hexagonal, octagonal, etc. Also, if desired, the protuberances 130
may be made frustoconical rather than conical with pointed apexes
136. In yet another embodiment the protuberances may be
hemispherical.
[0049] In FIG. 3 segmentation of compressible liner 310 is again
shown with the boundary lines 142. However in this embodiment only
the inner layer 124 is segmented whilst the outer layer is not
segmented. The segmentation of the inner layer 124, for this
embodiment of the compressible liner 310, is described in detail
with respect to FIG. 4.
[0050] FIG. 4 is an exploded view of the inner layer 124 and outer
layer 128 of FIG. 3. It can be seen that the outer layer 128
includes a multiplicity of conical recesses 132 sized and
configured to receive the protuberances 130 with surface contact in
the manner shown in FIGS. 1 and 2. The inner layer 124 may be
divided into a number of segments, 410, 412, 414, 416, 418, 420,
422, 424, 426, 428. In the illustrated embodiment 10 segments are
given. However alternate embodiments may have range in number of
segments from one to ten with a most preferable number of segments
being five. The use of a number of segments 410-428 allows the
compressibility or stiffness of the inner layer 124 to be adjusted
according to the level of customised impact protection required for
a portion or segment of the skull. For example the temporal
segments 414, 416 may be more compressible compared with the top of
skull segments 418, 420. The temporal sections of the skull being
more vulnerable to impact injury than other sections of the skull,
bone tests have indicated that the temporal portion of the skull is
a half to a third of the strength of other portions of the skull.
In another embodiment of the invention the EPS foam densities of
the various segments may be as follows: front segments 410, 412 of
density 30 kgm.sup.-3, temporal segments 414, 416 of density 25
kgm.sup.-3, top segments 418, 420 of density 35 kgm.sup.-3 and rear
segments 422, 424, 426, 428 of density 30 kgm.sup.-3.
[0051] In accordance with the above, the segments may have
circumferential shapes as defined by the boundary lines 142 as
illustrated in FIG. 4 or any other range of circumferential shapes
that allows adjoining segments to engage in a close fitting manner
along the boundaries 142. The choice of the circumferential shapes
of the individual segments being such that when the compressible
liner 110 is assembled the segments form a continuous inner layer
124 within the compressible liner 110. For example a segment's
planar circumferential shape may be any number of polygonal
shapes.
[0052] In yet another embodiment the outer layer 128 may also be
segmented (not shown) so that different foam densities may be used
about the skull for the outer layer 128. This embodiment may allow
for further, independent tailoring of the impact protection about
the skull. This embodiment may also be used to provide different
levels of protection required between, for example, a child and an
adult. The outer layer 128 may be segmented in a similar manner to
that described above for the inner layer 124. The planar
circumferential shapes of the outer layer 128 segments may or may
not correspond to segments of the inner layer. For example the
boundary lines 142 for the inner layer 124 and outer layer 128
segments may correspond as shown in FIGS. 1 and 2 or the boundary
lines 142 may be discontinuous between the inner layer 124 and the
outer layer 128 segments, described in detail with respect to FIG.
5.
[0053] In still yet another embodiment the density and dimensions
of the protuberances 130 and matching recesses 132 and the overall
compressible liner dimensions may be varied between segments of the
inner layer 124 and/or the outer layer 128 in order to vary the
compression or stiffness properties of the compressible liner 110.
For example the temporal segments 414, 416 may have conical
protuberances 130 of reduced base 138 diameter compared with the
other segments of the inner layer 124, however the temporal
segments 414, 416 may have a greater areal density of conical
protuberances 130 compared with the other segments of the inner
layer 124. For example for FIG. 4 the front segments 410, 412 may
together have 23 conical protuberances 130 with a base 138 diameter
of 20 mm, the top segments 418, 420 may together have 47 conical
protuberances 130 with the base 138 diameter also of 20 mm, the
rear segments together may have 39 conical protuberances 130 also
with the base 138 diameter of 20 mm whilst the temporal segments
may together have 36 conical protuberances 130 but with a base 138
diameter of 15 mm. In addition the range in the outer peripheries
140 distance (or the closest distance between adjacent bases 138)
may be from 0 to 20 mm and more preferably 5 to 15 mm, depending on
the segment. Corresponding separations between adjacent apex ends
136 of protuberances 130 may be up to 40 mm with most being between
25 to 35 mm.
[0054] In manufacture typically the outer layer 128 may be formed
in one or a number of pieces or segments using moulding techniques.
Similarly the inner layer 124 may be formed separately in one or a
number of pieces or segments. The pieces of the outer layer 128 and
inner layer 124 are then assembled and fused together to form the
compressible liner 110 suitable for a helmet or other impact
protection application. The dimensions, number and configuration of
the protuberances 130 and recesses 132 may be adjusted by a person
skilled in the art of fabrication techniques in order to be able to
form the compressible liner. For example the angle of the side of
the conical protuberances 130 and the shape of the apex end 136 may
be adjusted to enable suitable mould release properties depending
on a particular foam type or other material used.
[0055] FIG. 5 is a cross-sectional view of another embodiment of a
compressible liner 510 which schematically illustrates the
dimensions of the various elements of the compressible liner 110,
310, 510 as well as showing a discontinuous boundary line 142 for
segmentation. The dimensions given are by way of example for the
various embodiments described above and below. The compressible
liner 510 may have a thickness 524 ranging from 20 to 45 mm
depending on the application area and/or the portion of the skull
to be protected. In a preferred embodiment for a motorcycle helmet
the thickness 524 may be 25 mm in the temporal portion of a helmet
and 42 mm thick for the top or crown portions of the helmet. For a
compressible liner of uniform thickness, the preferred thickness
524 may be in a range from 30 to 35 mm for motorcycle helmets. For
helmets for use in horse related sports the thickness 524 of a
compressible liner may be reduced to the range of 15 to 25 mm or to
a more preferable uniform thickness 524 of 20 mm.
[0056] In FIG. 5 the outer periphery 140 spacing (between bases
138) is between the two inward pointing arrows. The joining surface
126 of the outer periphery 140 may be flat or radiused. For example
the radius of curvature may be in a range from 0 to 2.5 mm or more.
Consequently the protuberances 130 may cover the entirety of the
radially outward portion of the inner layer 124 or be spaced
apart.
[0057] In FIG. 5 the apex ends 136 of the protuberances 130 are
spaced from the outer surface 118 of the outer layer 128 by a
spaced region 526. The spaced region 526 may have a thickness in
the range of 1 to 5 mm or more. In an alternative embodiment the
apex ends 136 of the protuberances 130 of the inner layer 124 may
extend to be contiguous with the outer surface 118 of the outer
layer 128. For this embodiment the spaced region 526 thickness
would effectively be 0 mm.
[0058] The apex end 136 of the protuberance 130 may be pointed (or
sharp), rounded off with a radius of curvature in the range of 1 to
2 mm or simply truncated.
[0059] FIG. 5 also illustrates an embodiment of the segmented
compressible liner 510 where the boundary lines between the inner
layer 124 and outer layer 128 segments is discontinuous. The inner
layer 124 is divided into two segments 512, 514 by a boundary line
516. Whilst the outer layer 128 is divided into two segments 518,
520 at a different boundary line 522.
[0060] FIG. 6 illustrates an example alternate embodiment to FIG.
5. In FIG. 6 the space region 526 is increased so that the
protuberances 130 project into the outer layer 128 to approximately
50% of the thickness of the outer layer 128. The range in
penetration of the protuberances 130 into the outer layer 128 may
be from 50 to 100%. The corresponding boundary line 522 between the
two segments 518, 520 of the outer layer 128 is extended to
correspond to the increased space region 526.
[0061] With reference to FIGS. 5 and 6, the protuberances 130 may
have a height from base 138 to apex 136 in the range of
approximately 20 to 25 mm. The base 138 of the protuberances 130
may have a diameter or width in the range of approximately 15 to 22
mm.
[0062] In FIGS. 1, 2, 5 and 6 the first region 134 of the inner
layer 124 forms a thin layer upon which the bases 138 of the
protuberances 130 are linked. The thickness of the first region 134
may range from 5 to 10 mm or more, with the most preferable
thickness being 5 mm.
[0063] The compressible liner may be employed with any desired
helmet, including motorcycle helmets as well as helmets used by
construction personnel, riders of bicycles, horse riders, rodeo
riders, football players, baseball players and cricket players.
[0064] In yet another embodiment the compressible liner may be
retro-fitted into a helmet in order to improve its impact
protection. The retro-fitting of the compressible liner may be to
replace all the previous liner in a helmet or just particular
sections in a helmet's liner may only be replaced. A partial
retro-fitting may be particularly useful for those portions of the
liner adjacent to the temporal sections of the skull.
[0065] Foam Alternatives
[0066] Alternative materials that may used for the inner layer 124
and/or outer layer 128 include foams that are elastic. An elastic
foam having the property of enabling the compressible liner to
elastically compress so that the original dimensions and impact
protection performance prior to the impact are restored after the
impact. An alternative material to an elastic foam may be a
synthetic or natural rubber, either as a continuous solid or as a
composite with other materials, for example air, fabric or as
designed or selected by a person skilled in the art of shock,
vibration or impact absorber design or manufacture.
[0067] Other alternative materials to the foam for the compressible
liner may be viscoelastic or thixotropic. Such materials exhibits
viscous or liquid behaviour when no force or stress is applied to
them, however when a force is applied, such as an impact, the
material acts in an elastic fashion exhibiting stiffness to the
impacting force. An example of such material is a children's toy
commonly known as "silly putty". The inner layer 124 and/or outer
layer 128 may be fully or partially viscoelastic. An advantage of
the use of viscoelastic materials is that a compressible liner may
be constructed that readily conforms to the various skull shapes
(or any other body part) present in the human population and may
recover after impact sufficiently for the compressible liner to be
readily re-used.
Alternate Bicycle or Motorcycle Helmet
[0068] In an alternate embodiment to the compressible liner for a
helmet, the outer layer 128 may be replaced by a suitably
transparent or translucent material. For example the transparent or
translucent material may be a viscoelastic jell or a transparent
synthetic rubber material with the appropriate compressible and/or
stiffness properties. The outer shell 116 of the helmet may either
be absent or a suitably transparent or translucent material. The
inner layer 124 may be of an opaque material for example black
expanded polystyrene (EPS) foam. Such a helmet may have the
striking visual appearance of many visible cones or spikes
radiating from the person's head, an aesthetically appealing
feature to some bicycle and motorcycle riders, which may still
provide impact protection to the wearer of the helmet.
Vehicle Cabin Liner
[0069] FIG. 7 schematically illustrates the use of the compressible
liner 710 as a vehicle cabin liner (VCL) within a portion of a
vehicle cabin carrying people. The VCL compressible liner 710 may
be attached via an attachment layer 714 to the vehicle structure
712 that forms the interior of the vehicle cabin (not shown). For
car the vehicle structure 712 may be a door pillor, dashboard,
ceiling or any structure within the cabin of a car. The use of the
VCL compressible liner 710 within a vehicle cabin is of particular
interest for side impact collisions of passenger vehicle cars where
there is a tendency to a higher proportion of head injuries form
the impact of a passenger (or driver) head with the vehicle cabin
interior.
[0070] The VCL compressible liner 710 may be permanently affixed to
the vehicle structure 712 via the attachment layer 714 adhering to
the outer surface 118 of the compressible liner 710. For example
attached to side door pillars and windscreen pillars in passenger
vehicle cars. Alternatively the VCL compressible liner 710 may a
removable and replaceable fitting which may be retrofitted to
existing vehicles. For the removable and replaceable fitting the
attachment layer 714 may comprise of a material such as Velcro or
incorporate any one of many fastening methods known to a person
skilled in the art of interior fittings for vehicles.
[0071] The installation of the VCL compressible liner 710 within a
vehicle may further incorporate an optional interior trim liner 716
attached to the contact surface 122 of the VCL compressible liner
710. The interior trim liner 716 may provide aesthetic, tactile
and/or sound proofing properties. The interior trim liner 716, or
comfort liner, may be made of fabric, cushioning foam, "bubble
wrap" plastic and/or a plastic scuff lining.
[0072] Examples of vehicles that may be applicable to the use of
the VCL compressible liner 710 include: civilian cars and trucks,
military craft such as tanks, aircraft and the like, marine craft
and spacecraft. Yet another application area is the seat and head
rests of vehicles and in particular aircraft and spacecraft where
severe impacts may be encountered by those craft.
[0073] FIG. 8 is a cut-away illustration of the interior of a
civilian passenger car. FIG. 8 schematically shows the application
of the VCL compressible liner 710 to provide different zones of
impact protection about the vehicle cabin interior. For example
three different zones of protection may be identified, the front
and side pillars with the door window sills 810, the rear of the
front seats 812 and the dashboard and central console 814. For each
of the three zones 810, 812, 814 the outer layer 128 of the VCL
compressible liner 710 may be the same stiffness or compressibility
whilst the inner layer 124 varies in compressibility between the
zones 810, 812, 814 to provide the desired level of impact
protection with additional consideration of the day to day wear and
tear durability expected of an interior cabin lining for a car.
[0074] In yet another embodiment of the VCL compressible liner 710
(not shown), a zone of impact protection may be further divided.
For example the rear of the front seats 812 may have a higher
portion with an inner layer 124 segment that may be more
compressible than an inner layer 124 segment for a lower portion of
the rear of the front seats 812. This arrangement may provide a
zone of higher impact protection for the head of an unsecured rear
passenger where they are most likely to initially impact on the
upper portion of the rear of the front seats 812. The less
compressible lower portion of the rear of the front seats 812
allows for an increased durability to scuffing by the feet and legs
of rear passengers entering and exiting the rear of the passenger
cabin.
[0075] In another example application an embodiment of the
compressible liner 110 may be applied to the exterior front
surfaces of cars and trucks to aid in the impact protection of
pedestrians that may be struck by the car or truck.
Baby Capsules and Child Safety Seats
[0076] Yet another application of the compressible liner within a
vehicle is for baby capsules and child safety seats that are
typically used in cars, trucks or aircraft.
[0077] A baby capsule or child safety seat (CSS) may incorporate
segmented compressible liners according to the location of the
torso and head of the baby or child within the baby capsule or CSS
so as to offer the appropriate impact protection for those parts of
the baby's body. In other words different zones of impact
protection within a baby capsule or CSS may be provided. Typically
the compressible liner may be added to the interior of the baby
capsule or CSS, either as a number of panels to form the complete
compressible liner or the compressible liner may be inserted as one
unit liner. In another embodiment the compressible liner may form
the baby capsule or CSS. In addition the compressible liner may
also form the protective side panels or bolsters or in another
embodiment may be added to the existing side panels or bolsters of
a baby capsule or a child safety seat. Optionally, a comfort liner
may also be added to the baby capsule or CSS.
[0078] FIG. 9 schematically illustrates, in a perspective view, an
example of an embodiment of a baby compressible liner 910 for a
baby capsule. A baby capsule 912 is secured into an adult car seat
914 by the use of the baby capsule base 916 in the adult car seat
914 with rearward securing straps 918 anchoring to a suitable point
on the vehicle structure. A baby (not shown) is secured within the
removable cradle 920 of the baby capsule 912. Within the cradle 920
the baby compressible liner 910 may be segmented into two zones of
impact protection, the baby head zone 922 and a baby torso zone
924. In FIG. 9 the baby compressible liner 910 is shown as an
inserted liner into the structure of the cradle 920. In a preferred
embodiment the density of the EPS foam for the baby compressible
liner 910 may be in a lower range to that described above for
helmets. The inner layer 124 may have density in the range of 15 to
25 kgm.sup.-3, with an outer layer 128 of density in the range of
35 to 45 kgm.sup.-3. For increased impact protection for the baby's
head, the segments comprising the baby head zone 922 of the baby
compressible liner 910 may have EPS densities for the inner and
outer layers 124, 128 lower than the segments comprising the baby
torso zone 924.
[0079] In yet another embodiment of the baby compressible liner
910, the baby head zone 922 may be shaped in the partial form of a
helmet. With reference to FIG. 4 the baby head zone 922 may be
shaped in a form approximated by the rear segments 422, 424, 426,
428 and temporal segments 414, 416, with corresponding segments of
the outer layer 128.
[0080] FIG. 10 is a perspective view of a CSS 1012 with a CSS
compressible liner 1010. Typically the CSS 1012 may have a base
1014 resting upon an adult car seat 914. Upon the base 1014 is the
child seat 1016 that typically includes a seat, back rest and side
bolsters. The CSS 1012 is secured to the car seat 914 by use of the
adult lap sash seat belt (not shown) and/or additional securing
straps (not shown) to vehicle anchor points. The CSS compressible
liner 1010 may be segmented into two zones for impact protection;
the CSS head zone 1018 and the CSS torso zone 1020. Each zone 1018,
1020 may also feature side bolsters (or wings) 1022, 1024 to
"channel" or further confine and protect the child. In FIG. 10 the
CSS compressible liner 1010 is shown as an inserted liner onto the
structure of the child seat 1016. In a preferred embodiment the
density of the EPS foam for the CSS compressible liner 1010 may be
as described above for the baby compressible liner 910
Body Armour
[0081] Another application area of an embodiment of the
compressible liner 110 is its use in body armour, including
protective vests. For sports involving impacts such as motorcycle
riding, rodeo riding, football, gridiron, cricket and baseball,
body armour in the form of protective vests and pads are often worn
about the body. A body armour compressible liner may have an
embodiment adapted to impact protection in sports. For example the
body armour compressible liner may be a reduced thickness 524
appropriate to the sport, in the range of 5 to 30 mm. Materials
selected for the body armour compressible liner may be elastic and
robust to enable the compressible liner to be serviceable over many
impacts.
[0082] For ballistic body armour an embodiment of the body armour
compressible liner may be used in conjunction with ballistic
armour. The body armour compressible liner may absorb the impact
force of the ballistic armour in its reaction to an impacting
projectile.
[0083] FIG. 11 is a front elevation view of a protective vest 1112
with inserts of a body armour compressible liner 1110. The
protective vest 1112 may have Velcro shoulder tabs 1114 to aid the
wearer to put on and take off the protective vest 1112 garment.
Chest 1116 and abdominal 1118 compressible liner 1110 segments as
panels are shown inserted into the protective vest 1112, where
dashed lines 1120 indicate the extent of each segment 1116, 1118
for the front of the protective vest 1112 garment. The abdominal
compressible liner 1118 segments may offer a higher level of impact
protection compared with the chest compressible liner 1116 segments
because the rib cage in the chest offers a level protection for
internal organs that is absent for the abdomen.
Protection of High Value Articles
[0084] Another application area for the compressible liner may be
for the protection of high value articles such as: goods,
electronic devices, fragile mechanisms, animals, plants and the
like. Embodiments of the compressible liner may be used protect
high value articles in freight transit. Other embodiments may be
incorporated into military craft, aircraft and spacecraft for the
protection of sensitive equipment for improved survivability of
equipment in the event of a catastrophic impact to the craft.
Performance of the Compressible Liner
[0085] The performance of the compressible liner in the embodiments
described above may be further understood in terms of the following
descriptions of how the performance of impact protection apparatus
and methods are evaluated by those skilled in the art together with
the relative performance of the compressible liner. By way of
reference and example the following is incorporated herein:
"Improved Shock Absorbing Liner for Helmets", Australian Transport
Safety Bureau (ATSB), published in July, 2001, www.atsb.gov.au.
[0086] The compressible liner provides an initial low resistance to
the impact for the desired part of the human body, for example the
skull for a motorcycle helmet when a motorcycle rider's helmet
impacts the road surface. As the impact progresses the level of
resistance provided by the compressible liner increases in a
controlled manner so that controlled deceleration of the skull and
brain (continuing the prior example) is occurring throughout the
impact. In the following discussion the example embodiment of a
compressible liner with an EPS foam material in a motorcycle helmet
will be used, however it will be appreciated that similar remarks
may be made for all the other embodiments of the compressible liner
discussed above and below.
[0087] The particular configuration of the compressible liner with
the inner layer 124 and outer layer 128 of materials differing in
relative compressibility enables the compressible liner to provide
a continuous and gradual variation in compressibility and/or
stiffness as the compressible liner is compressed or crushed in an
impact.
[0088] The particular configuration of the compressible liner also
enables it to be readily manufactured with a reduced overall mass
for a helmet, in particular in comparison to single foam density
helmets. This is an advantage in reducing the effect of rotational
acceleration to the head and the neck during an impact.
Impact--Time Duration (Deceleration Time)
[0089] The compressible liner provides extended controlled
compression and crushing so as to extend the time period over which
the impact occurs. The human skull or any other body part may then
be more gradually decelerated to rest. The crush, or deformation
time, for the compressible liner may occur for a time up to and
beyond 20% over that for a liner with a single foam density. In
other terminology: the impact force translated to the skull is
reduced because the deceleration of the skull is slower due to the
action of the compressible liner.
Crushing
[0090] Crushing is the penetration into the compressible liner by
the skull during an impact. The compression of the compressible
liner dissipates the energy of the impact. The compressible liner
may crush up to and beyond 10% that of a liner constructed of a
single foam density.
Cracking
[0091] Slab and arc cracking during compression of an EPS foam
liner are commonly part of impact protection. Arc cracking is a
line of circumferential surface cracks about the penetration of the
skull into the foam liner. Slab cracking is a full thickness crack
through the foam liner in the region of the penetration into the
foam liner. Slab cracking is commonly seen in single density foam
liners and is to be avoided since impact protection by the foam
liner has then begun to fail.
[0092] The compressible liner exhibits no slab cracking during
impact tests. Arc cracking is considerably reduced for the
compressible liner. The reduction in arc cracking may in part be
due to the inner layer 124 making use of lower density foam in
comparison to common single density foam liners which commonly use
a foam density in the range of 45 to 90 kgm.sup.-3. Lower density
EPS foams will yield more in a plastic and/or elastic fashion than
higher density EPS foams, consequently a lower density foam inner
layer 124 is less likely to exhibit arc cracking. In addition the
use of lower density foam for the inner layer 124 allows the
contact surface 122 of the compressible liner to conform to the
skull better than a single density foam liner. Accordingly the
impact force is spread more evenly over a greater area of the
skull, a desirable feature.
Peak Deceleration (Impact Energy Attenuation or Shock Attenuation,
"g-force")
[0093] Australian and New Zealand national standards require that
the peak deceleration experienced within a helmet during a type of
simulated impact must be less than 300 g ("g" being the
gravitational acceleration of 9.8 ms.sup.-2). Similar standards
exist in North America and Europe. The peak deceleration for the
compressible liner in all situations tested was lower than
conventional single foam density liners and well below the
mandatory national standards requirements for Australia and New
Zealand.
Rotational Forces
[0094] The mass of the compressible liner within a helmet may
contribute to rotational forces experienced by the head in an
accident. It is a safety advantage for the helmet and the
compressible liner to be lightweight so as to reduce injuries
associated with rotational forces. Helmets with single density foam
liners that may perform similarly to the equivalent with a
compressible liner, in terms of the other performance tests
described above, are significantly larger and heavier. This is
because the single density foam liner must be thicker and of a
lower single density foam, resulting in extra liner mass as well as
a larger and heavier outer shell for the helmet.
[0095] It will be appreciated for the above description that whilst
the inner layer 124 is required to be more compressible and/or a
lower stiffness than the outer layer 128, the configuration of the
protuberances 130 and recesses 132 may be reversed such that the
protuberances are associated with the outer layer 128 and the
recesses with the inner layer 124 so that the invention is still
performed. In another embodiment the joining surface 126 may be
symmetric such that both the inner layer 124 and the outer layer
128 both have protuberances and recesses in an arrangement that
allows engagement of the inner layer 124 to the outer layer 128 at
the joining surface 126. However in all configurations, described
above and below, the compressibility of the inner layer 124 is more
than the compressibility of the outer layer 128. Or in stiffness
terms, the stiffness of the inner layer 124 is less than that of
the outer layer 128.
[0096] It will also be appreciated that the dimensions, capacities
and materials of the compressible liner given above and later are
given by way as examples for the embodiments described. Other
dimensions, capacities and materials to those given may also be
selected or designed by a person skilled in the art, for example
for other impact protection applications.
[0097] FIG. 12 schematically illustrates a cross-sectional view of
a double compressible liner 1210. The double compressible liner
1210 is an alternate embodiment of the compressible liner 510 shown
in FIG. 5. The double compressible liner 1212 is two compressible
liners 510 joined together at the outer surface 118, to form the
new join 1212. The double compressible liner 1210 may useful in
such applications as contact sports where vigorous body contact
between participants is common. In such situations it is desirable
that when two participants impact each other that both participants
receive the benefits of the initial low resistance of the inner
layer 124. Another example is the use of the double compressible
liner 1210 between sensitive mechanisms, or articles, so that the
two mechanisms both receive the benefit of the inner layer 124. The
double compressible liner 1210 may also be segmented (not shown) to
provide different zones of impact protection as described
above.
[0098] A continuum liner (not shown) may be constructed with
similar or superior properties to the compressible liner. The
continuum liner may include a liner fabricated in the desired
shape, for example a helmet, of a first material. The first
material may be highly compressible and/or a low stiffness, for
example a viscoelastic jell. It is then desired to produce the
effect of decreasing the compressibility (increased stiffness)
through the thickness of liner, proceeding in the direction from
the inside of the helmet to the outside of the helmet. To apply
such an increasing stiffening gradient the first material may be
transformed in a continuous fashion to a second material. Where the
second material has less compressibility (more stiffness) than the
first material and that the second material and first material
exist in various proportions throughout the continuum liner so as
to produce the desired stiffening gradient.
[0099] The second material may be produced by a number of
processes, including: [0100] Ionising radiation to cross link the
molecules of the first material to various degrees of cross linking
to form a second material. [0101] A chemical agent to transform the
first material to the second material to various degrees.
[0102] The ionising radiation or chemical agent may be applied to
the exterior of the helmet form, or other forms, made of the first
material. The level of transformation from the first material to
the second material would be carefully controlled by the level of
depth attenuation through the thickness of the continuum liner.
[0103] In a similar manner the level of ionising radiation or
chemical agent applied about the helmet form of the first material
may be controlled to impart different levels zones of impact
protection required about the helmet form. For the alternate
embodiment with zones of impact protection the boundary between the
segments for each zone may not be a discrete boundary line but a
gradient as results from the particular technique used to transform
the first material to the second material.
[0104] A different type of bicycle helmet (not shown) may be
produced without the presence of the outer layer 128. For this
helmet the apexes 136 of the protuberances 130 of the inner layer
124 are connected to the outer shell 116. A person skilled in the
art of helmet design and manufacture may select a suitable material
or materials to form the inner layer 128 so that appropriate safety
standards are met for this different bicycle helmet. For example
the inner layer 124 EPS foam density may be as described above or
transformed into two materials as per the continuum liner described
above. In another embodiment (not shown), of the different bicycle
helmet, the outer shell 116 may be conformal with the outer surface
of the inner layer 124 so as to form a hard outer layer in the
shape of the conical protuberances.
[0105] The use of a segmented liner, in which zones of different
impact protection are provided, can substantially reduce the weight
of the liner as compared with a non-segmented construction. Weight
saving is possible by using reduced density material where a high
resistance to applied force is not required. In the case of a
segmented helmet liner, the weight of the helmet may be reduced by
up to 20%, which is of considerable benefit to the wearer.
[0106] The liner of the invention may be pierced or apertured to
provide areas of no protection, for example to allow ventilation
openings. Such an arrangement is particularly useful for helmets
and the like.
[0107] In an embodiment of the invention one of the layers,
typically the inner layer, is constituted by a panel in the form of
a strip having protuberances or recesses thereon for co-operation
into apertures with the other layer. A strip may for example
comprise a single row of protuberances, and be moulded with a
curvature to suit the other layer, as would be required in for
example a helmet.
[0108] Several such strips may form part of an insert and be
moulded with a sprue to connect them. The sprue may comprise the
layer of material from which the protuberances project, and is
typically a single moulding. In one embodiment the sprue extends
transversely to the general direction of the strips. This
embodiment is particularly suitable for a helmet because the gap
between the strips can be aliged with the usual ventilation
openings.
[0109] Although the invention has been herein shown and described
in what is conceived to be the most practical and preferred
embodiments, it is recognized that departures can be made within
the scope of the invention, which are not to be limited to the
details described herein but are to be accorded the full scope of
the appended claims so as to embrace any and all equivalent
assemblies, devices and apparatus.
[0110] In this specification, the word "comprising" is to be
understood in its "open" sense, that is, in the sense of
"including", and thus not limited to its "closed" sense, that is
the sense of "consisting only of". A corresponding meaning is to be
attributed to the corresponding words "comprise, comprised and
comprises" where they appear.
[0111] It will further be understood that any reference herein to
known prior art does not, unless the contrary indication appears,
constitute an admission that such prior art is commonly known by
those skilled in the art to which the invention relates.
* * * * *
References