Note: Descriptions are shown in the official language in which they were submitted.
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HELMET
TECHNICAL FIELD
.. The present invention relates to a helmet.
BACKGROUND ART
Impact protection apparatuses generally aim to reduce the energy transferred
to an object,
such as a person to be protected, by an impact. This may be achieved by energy
absorbing
means, energy redirecting means, or a combination thereof. Energy absorbing
means may
include energy absorbing materials, such as a foam materials, or structures
configured to
deform elastically and/or plastically in response to an impact. Energy
redirecting means
may include structures configured to slide, shear or otherwise move in
response to an
.. impact.
Impact protection apparatuses include protective apparel for protecting a
wearer of the
apparel. Protective apparel comprising energy absorbing means and/or energy
redirecting
means is known. For example, such means are implemented extensively in
protective
headgear, such as helmets.
Examples of helmets comprising energy absorbing means and energy redirecting
means
include WO 2001/045526 and WO 2011/139224 (the entirety of which are herein
incorporated by reference). Specifically, these helmets include at least one
layer formed
from an energy absorbing material and at least one layer that can move
relative to the head
of the wearer of the helmet under an impact.
Implementing moving parts in a helmet has challenges. For example, ensuring
that friction
between moving parts under an impact can be overcome to allow enough relative
movement between parts can be challenging. Ensuring that the helmet can be
manufactured and assembled relatively easily can be challenging.
It is the aim of the present invention to provide a helmet that at least
partially addresses
some of the problems discussed above.
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SUMMARY OF THE INVENTION
According to an aspect of the disclosure there is provided a helmet,
comprising an outer
shell; a head mount, configured to be mounted on the top of the head of a
wearer of the
helmet; wherein the head mount is suspended within the outer shell such that,
in use, an air
gap is provided between the head mount and the outer shell; the head mount
comprises a
plurality of straps, that are configured to extend across the top of the head
of a wearer of
the helmet, and a head ring that at least partially surrounds the head of a
wearer of the
helmet, extending around the craniocaudal axis; and the helmet further
comprises: a head
engagement device that is provided on a surface of the head mount, that is
configured to
face the head of a wearer of the helmet, such that the head engagement device
can move
relative to the head mount; and a head engagement device support that is
configured to
inhibit the movement of the head engagement device through gaps between the
straps
and/or head ring of the head mount into the air gap between the head mount and
the outer
shell.
In an arrangement, the head engagement device support comprises a crown
section
connected to at least one of the straps at a location corresponding to the top
of the head of a
wearer of the helmet and at least one limb section that extends from the crown
section to
the head ring and is connected to the head ring.
In an arrangement, the head engagement device support comprises at least two
limb
sections, each extending from the crown section to a location on the head ring
corresponding to a respective side of the head of a wearer of the helmet.
In an arrangement, the head engagement device support comprises at least one
limb section
extending from the crown section to a location on the head ring corresponding
to the front
of the head of a wearer of the helmet and/or at least one limb section
extending from the
crown section to a location on the head ring corresponding to the back of the
head of a
wearer of the helmet.
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In an arrangement, the crown section of the head engagement device support
comprises at
least one slot; and the head engagement device support is connected to the
head mount by
at least one strap of the head mount passing through at least one slot in the
crown section.
In an arrangement, the crown section of the head engagement device support is
connected
to the headmount by an extension of the crown section of the head engagement
device
support that extending around at least one of the straps and connecting to
itself.
In an arrangement, at least one limb section of the head engagement device
support is
connected to the head ring by an end of the limb section extending around a
section of the
head ring and connecting to itself
In an arrangement, the helmet comprises at least one connector configured to
connect the
head engagement device to the head engagement device support while permitting
the head
engagement device to move relative to the head engagement device support.
In an arrangement, at least one connector is provided on the crown section of
the head
engagement device support.
In an arrangement, at least one connector is provided on a limb section of the
head
engagement device support.
In an arrangement, at least one connector on a limb section of the head
engagement device
support is provided at a location at which the limb section is connected to
the head ring.
In an arrangement, the connector comprises a sheet of elastically deformable
material; and
the sheet of elastically deformable material is connected to one of the head
engagement
device support and the head engagement device at an inner region of the sheet
of
elastically deformable material and is connected to the other of the head
engagement
device support and the head engagement device at a peripheral region of the
sheet of
elastically deformable material.
In an arrangement, the head engagement device support comprises at least one
outer
surface formed from a fabric or felt.
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In an arrangement, the head engagement device support is formed from a
material
comprising a layer of foam laminated between two layers of fabric or felt; and
the foam
layer is stiffer than the layers of fabric or felt.
In an arrangement, the head engagement device support is formed from two
layers of
fabric or felt with a plastic plate inserted between them that has a shape
corresponding to at
least a part of the head engagement device support.
In an arrangement, a low friction interface is provided between the head
engagement
device and at least one of the head mount and the head engagement device
support.
In an arrangement, the low friction interface is provided by a low coefficient
of friction
between the surfaces of the head engagement device and the head mount and/or
the head
engagement device support.
In an arrangement, the head engagement device is connected to the head mount.
In an arrangement, the head mount comprises a plurality of straps that extend
between an
opposing pair of connection points on the outer shell.
In an arrangement, the head engagement device is provided as a single
component.
In an arrangement, the head engagement device is formed from plural separate
sections.
In an arrangement, the head engagement device comprises a crown region that is
configured to be located between the top of the head of a wearer of the helmet
and the head
mount, and a frontal region that is configured to be located adjacent the head
ring.
In an arrangement, the head engagement device further comprises an
intermediate region
that connects the crown region to the frontal region.
In an arrangement, the head engagement device comprises a plate of material,
optionally
shaped to conform to the head of a wearer of the helmet.
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In an arrangement, in the absence of an impact on the helmet, the separation
between the
outer shell and the head mount at a location corresponding to the top of the
head of a
wearer provided by the air gap is at least lOmm, optionally at least 15mm,
optionally at
least 20mm, optionally at least 30mm, optionally at least 40mm.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in detail below, with reference to the accompanying
figures, in which:
Fig. 1 schematically shows a cross-section through a first example helmet;
Fig. 2 schematically shows a cross-section through a second example helmet;
Fig. 3 schematically shows a cross-section through a third example helmet;
Fig. 4 schematically shows a cross-section through a fourth example helmet;
Fig. 5 depicts the inside of an example of a helmet according to the
arrangement
depicted in Fig. 1;
Figs. 6, 7 and 8 depict a connector for use in a helmet of the arrangement
depicted
in Fig. 5;
Fig. 9 depicts the inside of a further example of a helmet;
Fig. 10 depicts the inside of a further example of a helmet;
Fig. 11 depicts the inside of a further example of a helmet;
Fig. 12 depicts the inside of a further example of a helmet;
Fig. 13 depicts the helmet of Fig. 12 from the side;
Fig. 14 depicts a head engagement device support for use within a helmet;
Fig. 15 depicts a helmet incorporating the head engagement device support of
Fig.
14;
Fig. 16 depicts an alternative head engagement device support;
Fig. 17 depicts a helmet incorporating the head engagement device support of
Fig.
16;
Fig. 18 depicts an alternative arrangement of a head engagement device
support;
Figs. 19 and 20 depict an arrangement for connecting a head engagement device
support to straps within a helmet;
Fig. 21 depicts an arrangement for connecting a head engagement device support
to
the head ring of a helmet;
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Figs. 22 and 23 depict example locations of connectors for connecting a head
engagement device to a head engagement device support;
Fig. 24 depicts the inside of an example of a helmet incorporating a head
engagement device support;
Fig. 25 depicts schematic in cross-section the structure of a head engagement
device support;
Fig. 26 depicts an alternative structure of a head engagement device support;
and
Fig. 27 depicted an example of a connector.
DETAILED DESCRIPTION
It should be noted that the Figures are schematic, the proportions of the
thicknesses of the
various layers, and/or of any gaps between layers, depicted in the Figures may
have been
exaggerated or diminished for the sake of clarity and can of course be adapted
according to
need and requirements.
General features of the example helmets are described below with reference to
Figs. 1 to 4.
Figs. 1 to 4 show example helmets 1 comprising an outer layer 2, or shell. The
purpose of
the outer layer 2 may be to provide rigidity to the helmet. This may help
spread the impact
energy over a larger area of the helmet 1. The outer layer 2 may also provide
protection
against objects that might pierce the helmet 1. Accordingly, the outer layer 2
may be a
relatively strong and/or rigid layer, e.g. compared to an energy absorbing
layer 3. The
outer layer 2 may be a relatively thin layer, e.g. compared to an energy
absorbing layer 3.
The outer layer 2 may be formed from a relatively strong and/or rigid
material. Preferable
such materials include a polymer material such as polycarbonate (PC),
polyvinylchloride
(PVC), high density polyethylene (HDPE) or acrylonitrile butadiene styrene
(ABS) for
example. Advantageously, the polymer material may be fibre-reinforced, using
materials
such as glass-fibre, Aramid, Twaron, carbon-fibre and/or Kevlar.
As shown in Fig. 4, one or more outer plates 7 may be mounted to the outer
layer 2 of the
helmet 1. The outer plates 7 may be formed from a relatively strong and/or
rigid material,
for example from the same types of materials as from which the outer layer 2
may be
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formed. The selection of material used to form the outer plates 7 may be the
same as, or
different from, the material used to form the outer layer 2.
The helmet of Fig. 4 is configured such that the outer plates 7 are able to
slide relative to
the outer layer 2 in response to an impact. A sliding interface may be
provided between
the outer plates 7 and the outer layer 2.
Friction reducing means, to reduce the friction at the sliding interface, may
be provided by
forming the outer layer 2 and/or the outer plates 7 from a low friction
material, providing
an additional low friction layer on a surface of the outer layer 2 and/or the
outer plates 8
facing the sliding interface, by applying a low friction coating to the outer
layer 2 and/or
the outer plates 7, and/or applying a lubricant to the outer layer 2 and/or
the outer plates 7.
The helmet 1 shown in Fig. 4 also comprises connectors 5 attached to the outer
plates 7
The connectors 5 are also attached to the outer layer 2 to allow relative
sliding between the
plates 7 and the outer layer 2. Alternatively or additionally, one or more of
the connectors
5 may be connected to another part of the remainder of the helmet 1, such as
an energy
absorbing layer 3. The connectors 5 may also be connected to two or more parts
of the
remainder of the helmet 1.
In such an arrangement, in the event of an impact on the helmet 1, it can be
expected that
the impact would be incident on one or a limited number of the outer plates 7.
Therefore,
by configuring the helmet such that the one or more outer plates 7 can move
relative to the
outer layer 2 and any outer plates 7 that have not been subject to an impact,
the surface
receiving the impact, namely one or a limited number of outer plates 7, can
move relative
to the remainder of the helmet 1. In the case of an impact, this may reduce
the rotational
acceleration of the head of a wearer.
It should be understood that such an arrangement of outer plates 7 may be
added to any
helmet described herein.
Figs. 2 to 4 show example helmets 1 comprising an optional energy absorbing
layer 3. The
purpose of the energy absorbing layer 3 is to absorb and dissipate energy from
an impact in
order to reduce the energy transmitted to the wearer of the helmet. Within the
helmet 1,
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the energy absorbing layer may be the primary energy absorbing element.
Although other
elements of the helmet 1 may absorb that energy to a more limited extent, this
is not their
primary purpose.
The energy absorbing layer 3 may absorb energy from a radial component of an
impact
more efficiently than a tangential component of an impact. The term "radial"
generally
refers to a direction substantially toward the centre of the wearers head,
e.g. substantially
perpendicular to an outer surface of the helmet 1. The term "tangential" may
refer to a
direction substantially perpendicular to the radial direction, in a plane
comprising the radial
direction and the impact direction.
The energy absorbing layer may be formed from an energy absorbing material,
such as a
foam material. Preferable such materials include expanded polystyrene (EPS),
expanded
polypropylene (EPP), expanded polyurethane (EPU), vinyl nitrile foam; or
strain rate
sensitive foams such as those marketed under the brand-names PoronTM and
D3OTM.
Alternatively, or additionally, the energy absorbing layer may have a
structure that
provides energy absorbing characteristics. For example, the energy absorbing
layer may
comprise deformable elements, such as cells or finger-like projections, that
deform upon
impact to absorb and dissipate the energy of an impact.
As illustrated in Fig. 3, the energy absorbing layer 3 of the helmet 1 may be
divided into
outer and inner parts 3A, 3B. These parts 3A, 3B may be configured to rotate
relative to
each other.
The energy absorbing layer is not limited to one specific arrangement or
material. The
energy absorbing layer 3 may be provided by multiple layers having different
arrangements, i.e. formed from different materials or having different
structures. The
energy absorbing layer 3 may be a relatively thick layer. For example, it may
be thickest
layer of the helmet 1.
Where used, the energy absorbing material layer may be provided as a shell
over
substantially all of the surface of the hard shell facing the wearer's head,
although
ventilation holes may be provided. Alternatively or additionally, localised
regions of
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energy absorbing material may be provided between the hard shell and a head
mount
(described below). For example, a band of energy absorbing material may be
provided
around the lower edge of the outer shell and/or a section of energy absorbing
material may
be provided to be located above the top of the wearer's head.
In some example helmets, the outer layer 2 and/or the energy absorbing layer 3
may be
adjustable in size in order to provide a customised fit. For example the outer
layer 2 may
be provided in separate front and back parts. The relative position of the
front and back
parts may be adjusted to change the size of the outer layer 2. In order to
avoid gaps in the
outer layer 2, the front and back parts may overlap. The energy absorbing
layer 3 may also
be provided in separate front and back parts. These may be arranged such that
the relative
position of the front and back parts may be adjusted to change the size of the
energy
absorbing layer 3. In order to avoid gaps in the energy absorbing layer 3, the
front and
back parts may overlap.
Fig. 1 shows an example helmet 1 comprising a head mount 20. Although not
shown in
Figs. 2 to 4, these example helmets also comprise a head mount 20. The head
mount 20
may be provided to mount the helmet 1 on the head of a wearer. In some
arrangements,
this may improve the comfort of the wearer.
The head mount 20 may be provided in any form that can function to contribute
to
mounting the helmet to the wearer's head. In some configurations, it may
assist in
securing the helmet 1 to the wearer's head but this is not essential. The head
mount 20
may be configured to at least partially conform to the head of the wearer. For
example, the
head mount 20 may be elasticated and/or may comprise an adjustment mechanism
for
adjusting the size of the interface layer 20. In an arrangement, the head
mount 20 may
engage with the top of a wearer's head.
The head mount 20 may be removable. This may enable the head mount 20 to be
cleaned
and/or may enable the provision of an interface layer that is configured to
fit a specific
wearer.
As shown in Fig. 1 the head mount 20 is suspended within the rest of the
helmet, e.g. a
cavity formed therein for accommodating the head, (e.g. the outer shell 2
and/or optional
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energy absorbing layer 3) such that an air gap 21 is provided between the rest
of the helmet
and the head mount 20. The head mount 20 may be connected to the rest of the
helmet
(e.g. to the outer shell 2 and/or optional energy absorbing layer 3) by
connectors 25.
Helmets of this type are commonly used for industrial purposes, such as by
builders, mine-
workers or operators of industrial machinery. However, helmets based on such
an
arrangement may be used for other purposes.
In a helmet 1 such as that depicted in Fig. 1, the provision of an air gap 21
between the
inner surface of the outer shell 2 and the head mount 20 is intended to ensure
that loading
caused by an impact on the outer shell 2 is spread across a wearer's head. In
particular, the
load is not localised on a point on the wearer's head adjacent the point of
impact on the
helmet 1. Instead, the load is spread across the outer shell 2 and,
subsequently, spread
across the head mount 20 and therefore spread across the wearer's skull.
During an impact, some of the energy of the impact may be absorbed by
deformation of
parts of the helmet, such as the head mount, reducing the size of the air gap.
Accordingly,
the size of the air gap 21 between the outer shell 2 and the head mount 20 may
be chosen
to ensure that, under an impact on the helmet below a threshold force that the
helmet is
designed to withstand, the head mount 20 does not come into contact with the
outer shell 2,
namely the air gap 21 is not entirely eliminated, such that the impact may be
directly
transferred from the hard shell to the head mount 20. However, in some example
helmets,
for impacts above the threshold force, the gap 21 may be eliminated, e.g. at a
specification
location such as the location of impact, such that the rest of the helmet
contacts the head
mount 20. Such example helmets may comprise an energy absorbing layer 3, which
is
provided in the space that would otherwise be empty and forming the air gap
21. In other
words, part of the air gap 21 may be replaced by an energy absorbing layer.
This may
bring the rest of the helmet closer to the head mount 20.
In an arrangement, the helmet 1 may be configured such that, in the absence of
an impact
on the helmet, the separation between the outer shell 2 and the head mount 20
at a location
corresponding to the top of the head of a wearer is at least 10 mm, optionally
at least 15
mm, optionally at least 20 mm, optionally at least 30 mm, optionally at least
40 mm. The
magnitude of the impact that the helmet 1 is designed to withstand, and
therefore the size
of the air gap 21, may depend upon the intended use of the helmet 1. It should
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understood that, depending on the intended use of the helmet the size of the
air gap 21 may
be different at different locations. For example, the air gap 21 may be
smaller at the front,
back or side of the helmet than it is at the location corresponding to the top
of the head of
the wearer.
In arrangements that include energy absorbing layer, the energy absorbing
layer may
contribute to the helmet's ability to withstand radial impacts. In particular
in arrangements
in which the energy absorbing material is located within the air gap between
the outer shell
2 and the head mount 20 at the location corresponding to the top of the
wearer's head, it
will be appreciated that the gap between the head mount and the surface of the
energy
absorbing layer will be smaller than the gap between the outer shell and the
head mount,
and may be eliminated altogether. Additionally, as a result of the energy
absorbing
material's contribution in the event of a radial impact, a smaller gap between
the outer
shell and the head mount may be required than would be the case in the absence
of the
energy absorbing material.
In some arrangements, the head mount 20 may include a head band, or head ring,
that at
least partially surrounds the wearer's head. Alternatively or additionally,
the head mount
may include one or more straps that extend across the top of the wearer's
head.
20 Alternatively or additionally, the head mount 20 may include a cap or
shell that
encapsulates an upper portion of the wearer's head. Straps or bands that form
part of the
head mount may be formed from Nylon fabric. Other materials may alternatively
or
additionally be used.
Figs. 5 shows an example of a helmet of the type schematically depicted in
Fig. 1. As
shown, the head mount includes a plurality of straps 20 that extend across the
top of the
head of a wearer of the helmet 1. The straps 20 may be connected at connection
points to
the outer shell 2 by any of a plurality of known methods. For example, the
outer shell 2
may be moulded to include sockets into which connectors 25 may be inserted.
In the arrangement depicted in Fig. 5, the head mount is formed from two
straps 20 that
each extend between a pair of connectors 25 positioned such that the straps 20
extend
across the head of the wearer of the helmet. For example, a first strap 20 may
extend from
a rear left position to a forward right position and a second strap 20 may
extend from a rear
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right position to a forward left position. However, it should be appreciated
that many other
arrangements may be used. For example, additional straps may be provided such
that there
are three, four or more straps extending across the top of the head of the
wearer. Similarly,
the position of the connection points of the straps 20 to the remainder of the
helmet 1 may
.. be different from that depicted in Fig. 5.
In an arrangement where different straps 20 are in proximity to each other,
for example, at
the top of the wearer's head, the straps 20 may not be connected to each
other, permitting
some movement of one strap relative to another. In other arrangements, the
straps 20 may
.. be connected to each other where they cross. In a further arrangement, the
head mount
may include one or more straps that extend from a connection point to the
remainder of the
helmet 1 to a point at which it is connected to other straps, for example, at
a location
corresponding to the top of the head of a wearer of the helmet.
Further straps, e.g. chin straps, may be provided to secure the helmet 1 to
the head of the
wearer.
As shown in Fig. 5, the helmet 1 further includes a head engagement device 40.
The head
engagement device 40 is mounted on a surface of the head mount, namely the
straps 20 in
the arrangement depicted in Fig. 5, that faces the head of a wearer when the
wearer is
wearing the helmet 1. In other words, the head engagement device 40 is
provided on the
opposite side of the head mount 20 from the airgap that exists between the
head mount 20
and the outer shell 2.
As is discussed in further detail below, the head engagement device 40 is
mounted such
that the head engagement device 40 can move relative to the head mount 20. In
other
words, the head engagement device 40 and the head mount 20 are not rigidly
connected to
each other. A low friction interface may be provided between the head mount 20
and the
head engagement device 40. This may facilitate the movement of the head
engagement
.. device 40 relative to the head mount 20 under an impact to the helmet 1.
In the event of an oblique impact on the helmet 1 while it is being worn by a
wearer, the
ability of the head engagement device 40 to move relative to the head mount 20
enables
movement, such as a rotation, of the helmet 1 relative to the wearer's head.
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The low friction interface between the head mount 20 and the head engagement
device 40
may be implemented by any of a variety of methods. For example, the head
engagement
device 40 may be formed from a material that provides a sufficiently low
coefficient
friction between it and the head mount 20. For example, it may be formed from
polypropylene (PP), Nylon, polycarbonate (PC), a polyketone, or any other low
friction
material, such as those discussed above. By suitable material selection for
forming one or
both of the head mount and the head engagement device, the low friction
interface may be
provided without provision of additional components and/or surface treatments.
In other arrangements, one or both of the surfaces of the head mount 20 and
the head
engagement device 40, where they are in contact, may be provided with a
separate sliding
facilitator, such as a patch of low friction material or a coating of another
material, which
could be another polymer with a low coefficient of friction or a section of a
fabric material
.. or felt, or may have a lubricant applied to it.
Possible low friction materials include waxy polymers such as PC, TPU, Nylon
(e.g.
brushed Nylon), PTFE, ABS, PVC, PFA, EEP, PE and UHMWPE, TeflonTm.
Alternatively, the low friction layer may be formed from a woven or nonwoven
fabric.
Such low friction materials may have a thickness of roughly 0.1-5 mm, but
other
thicknesses can also be used, depending on the material selected and the
performance
desired.
If layers of low friction material are provided on both opposing surfaces,
namely the
surface of the head mount 20 and the surface of the head engagement device,
these may be
formed from the same materials or different materials. In one example, a
polymer
material, such as PC, may be provided to the surface facing the head mount 20
and the
surface of the head mount 20 may be provided with a fabric material.
In some examples, a sliding interface may be provided between two sheets of
ribbed fabric
arranged such that the rib directions are perpendicular to each other, thus
forming the
sliding interface between. Preferably, the ribbed fabric is a tricot fabric.
Preferably, the
tricot fabric has a dull side and a shiny side and the respective shiny sides
face each other
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at the sliding interface. The two sheets of fabric may be provided
respectively to the head
mount 20 and the rest of the helmet (e.g. an energy absorbing layer 3 or outer
shell 2).
Alternatively, or additionally, lubricating materials include oils, polymers,
microspheres,
or powders, or combinations thereof may be used at the sliding interface. For
example,
these may be applied to a surface of the helmet facing the head mount 20.
In one example the low friction material or lubricating material may be a
polysiloxane-
containing material. In particular the material may comprise (i) an organic
polymer, a
polysiloxane and a surfactant; (i) an organic polymer and a copolymer based on
a
polysiloxane and an organic polymer; or (iii) a non-elastomeric cross-linked
polymer
obtained or obtainable by subjecting a polysiloxane and an organic polymer to
a cross-
linking reaction. Preferred options for such materials are described in
W02017148958.
In one example the low friction material or lubricating material may comprise
a mixture of
(i) an olefin polymer, (ii) a lubricant, and optionally one or more further
agents. Preferred
options for such materials are described in W02020115063.
In one example the low friction material or lubricating material may comprise
an ultra high
molecular weight (UHMW) polymer having a density of < 960 kg/m3, which UHMW
polymer is preferably an olefin polymer. Preferred options for such materials
are described
in W02020115063.
In one example the low friction material or lubricating material may comprise
a
.. polyketone.
In some arrangements, it may be desirable to configure the sliding interface
such that the
static and/or dynamic coefficient of friction between materials forming
sliding surfaces at
the sliding interface is between 0.001 and 0.3 and/or below 0.15. The
coefficient of
.. friction can be tested by standard means, such as standard test method ASTM
D 1894.
In some examples, the sliding interface may be provided by a shearing layer,
rather than a
layer of low friction material. In such examples, the layer of low friction
materials
described above may be replaced by shearing materials or structures. These
materials
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generally comprise two layers that are able to shear with respect to each
other to allow
relative sliding between layers of the helmet.
The head engagement device 40 may be connected to the helmet 1 in any suitable
manner
that permits movement of the head engagement device 40 relative to the head
mount 20.
For example, the head engagement device 40 may be connected to the outer shell
2, for
example by connecters that permit movement of the head engagement device 40
relative to
the outer shell 2. Such connectors may include elastic components that can
stretch when
movement of the head engagement device 40 relative to the outer shell 2 is
required.
In an arrangement, such as that depicted in Fig. 5, the head engagement device
40 may be
connected to the head mount, for example to the one or more straps 20 that is
part of the
head mount.
Where the head engagement device 40 is connected to the head mount, connectors
45 may
be used that permit some movement of the head engagement device 40 relative to
the part
of the head mount to which it is connected.
In an arrangement, a connector 45 may have first and second ends 46, 47 joined
to the head
engagement device 40 at respective first and second locations on the head
engagement
device 40 and positioned such that a strap 20 of the head mount is located
between the
connector 45 and the head engagement device 40 in a region between the first
and second
locations on the head engagement device 40. In such an arrangement, the strap
20 may not
be fixedly secured to any part of the connector 45 such that the strap can
slide in its
.. lengthwise direction and/or sideways relative to the connector 45. However,
the head
engagement device 40 is restricted from being completely removed from the
strap 20.
In such an arrangement, the connector 45 may be formed from a material, or
covered with
a material, that provides a sufficiently low coefficient of friction between
it and the strap
20 that movement of the head engagement device relative to the head mount is
not
significantly reduced, and therefore does not significantly hinder the
function of the helmet
1. Alternatively or additionally, the connector 45 may be formed from an
elastic material
such that, to the extent that a part of the connector 45 does not slide
relative to the strap 20,
the strap can move relative to the first and second parts 46, 47 of the
connector 45 joined to
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the head engagement device 40, for example by stretching of the connector,
permitting the
desired movement of the head engagement device relative to the head mount.
In an arrangement such as the depicted in Fig. 5, the connector 45 may be
formed from an
.. elongate section of material. For example, the connector 45 may be formed
from a section
of material in the shape of a cord, band or tape. Such a material may, for
example, be
generally round or rectangular in cross section. The connector may be formed
from an
elastic material, which may be beneficial for the function of the connector in
the event of
an impact on the helmet 1, as described above, and/or may facilitate assembly
of the
helmet 1. In an arrangement, the connector 45 may be formed from an elastic
material that
is coated with a layer of fabric. The connector 45 may alternatively or
additionally be
formed from silicone, rubber or another elastic plastic material.
A connector such as that disused above may be joined to the head engagement
device 40 at
the first and second locations by any suitable method, including for example
adhesive or
mechanical methods such as a snap-fit connection. Alternatively two ends of
the elongate
material may be tied to each other and/or at least one end may be tied to a
part of the
helmet 1 in order to secure it.
In an arrangement, as schematically depicted in Figs. 6 to 8, the length of
material 50 used
to form the connector 45 may be terminated with a component, such as a
relatively short
bar 51. The bar 51 is connected to the elongate material 50 such that the
length of the bar
51 is at an angle to the elongate length of the material, optionally
perpendicular. As shown
in Fig. 7, during assembly, the bar 51 may be inserted in a lengthwise
direction through a
hole 41 in the head engagement device 40. However, as shown in Fig. 8, the bar
51 will
subsequently naturally orient itself against the surface of the head
engagement device 40
such that the bar 51 cannot pass back through the hole. It will be appreciated
that in such
an arrangement, the hole 41 in the head engagement device 40 may be configured
to be
larger than the cross-section of the bar 51 but be smaller than the length of
the bar 51.
In an arrangement such as that depicted in Fig. 5, the strap 20 is connected
to the head
engagement device 40 such that the strap 20 is on the opposite side of the
head engagement
device 40 from the head of a wearer of the helmet. Accordingly, the connector
45 is also
predominantly on the opposite side of the head engagement device 40 from the
head of the
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wearer of a helmet. In a connector arrangement as discussed above and depicted
in Figs. 6
to 8, the connector 45 may be configured such that the length of material
forming the
connector 45 extends through a hole 41 in the head engagement device 40 from
the side
against which the strap 20 is in contact, with the result that the bar 51 is
positioned on the
surface of the head engagement device 40 facing the head of a wearer of the
helmet.
If this is undesirable, for example if it impacts on the comfort of the wearer
of the helmet
or if it is desirable to conceal the bar 51, either for aesthetic reasons or
to reduce the risk of
damage to the connector 45 and/or the risk of tampering, a second hole 41 may
be
provided in the head engagement device 40 at each location used for securing
the
connector. In such an arrangement, the length of material may pass through one
hole from
the region in which the connector is engaging with the strap, pass across a
section of the
head engagement device 40 between the two holes 41, and then pass through the
second
hole. In such an arrangement, the bar 51 is held on the same side of the head
engagement
device 40 as the strap 20, namely on the opposite side of the head engagement
device 40
form the head of the wearer.
In an arrangement, each connector 45 may be formed from its own separate
section of
elongate material. Alternatively, one or more connectors 45 may be formed from
sections
of a single piece of the elongate material. For example, plural connectors 45
may be
formed in a manner corresponding to the above but, in place of a bar 51 at a
location where
the connector 45 joins the head engagement device 40, the elongate material
may extend to
another connector 45. In an arrangement, all of the connectors 45 used to
connect a head
engagement device 40 to the head mount may be formed from a single length of
elongate
material.
As shown in Fig. 5, in an arrangement where the head mount includes straps 20
that extend
across the head of a wearer of the helmet between two connection points on the
outer shell
2, a pair of connectors 45 may be provided for each strap 20 on opposite sides
of the head
engagement device 40. Similarly, at least one connector 45, optionally a pair
of connectors
45, may be provided for each strap 20. However, this is not essential. For
example, as
shown in Fig. 9, fewer connections may be provided between the head engagement
device
and the head mount, such as the straps 20. In the arrangement depicted in Fig.
9, for
example, connectors 45 may only be provided at the rear of the helmet 1.
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Fig. 10 depicts an alternative arrangement for connecting the head engagement
device 40.
As shown, the head engagement device 40 may include holes 60 though which a
strap 20
that is part of a head mount may pass.
As discussed above, other arrangements for connecting the head engagement
device 40
may alternatively or additionally be used. For example, an elastically
deformable
connector may be provided between the head mount and the head engagement
device 40
such that a first part of the connector is secured to a part of the head
mount, such as a strap
20, and a second part of the connector is secured to a part of the head
engagement device
40. Movement of the head engagement device relative to the head mount may be
enabled
by stretching and/or other deformation of the connector. Such a connector may
be secured
to one or both of the surfaces of the head mount and head engagement device
that face
each other. The connector may be secured to one or both of the head mount and
head
engagement device by any suitable means, including for example, by means of
hook and
loop material and/or by adhesive.
As shown in the arrangements depicted in Figs. 5, 9 and 10, the head
engagement device
40 may be provided as a single component, such as a single layer of material.
However,
this need not be the case. For example, the head engagement device may be
formed from
plural separate sections. The separate sections may remain separate and, for
example, be
separately connected to the head mount and/or other parts of the helmet 1.
Alternatively,
two or more sections may be connected during assembly of the helmet. In an
arrangement,
a separate section of the head engagement device may be connected to each of,
or a subset
of, the straps 20 that form, or are part of, the head mount.
In an arrangement, the head engagement device, or one or more parts of it may
be formed
by injection moulding or vacuum-forming. It may therefore be formed to have a
shape that
conforms to the shape of the head of a wearer of the helmet.
In arrangement of a helmet 1, such as depicted in Fig. 5, the head mount may
include a
head ring 30 that engages at least the forehead of a wearer of the helmet and
may
substantially surround the head of the wearer. The head ring 30 may be
oriented to extend
around the craniocaudal axis. It should be appreciated that such a head ring
30 may be
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connected to the helmet 1 separately from the remainder of the head mount,
such as straps
20. Alternatively the head ring 30 may be connected to the helmet 1 by means
of the
straps 20. As a further alternative, the straps 20 may be connected to the
rest of the helmet
1 by means of the head ring 30.
In an arrangement in which the helmet 1 includes a head ring 30, the head
engagement
device 40 may include a crown region 43 that is configured to be located
between the top
of the head of the wearer of the helmet and the head mount, such as straps 20,
and a frontal
region 44 that is configured to be located adjacent to the head ring 30, at
least in the region
of the forehead of the wearer of the helmet. The frontal region 44 of the head
engagement
device may be arranged such that it can slide relative to the portion of the
head ring to
which it is adjacent, in the same manner as other sections of the head
engagement device
40 are arranged to be able to move relative to other sections of the head
mount, such as
straps 20 where used.
The frontal region 44 of the head engagement device may be connected to the
head ring
and/or to the outer shell 2, for example by connectors that are configured to
permit
movement of one part relative to another, enabling movement of the frontal
region 44 of
the head engagement device 40 relative to the head ring 30. Alternatively or
additionally,
the frontal region 44 of the head engagement device 40 may be connected to the
helmet 1
by way of an intermediate region 48 of the head engagement device 40. In
particular, the
intermediate region 48 of the head engagement device 40 may connect the
frontal region
44 to the crown region 43. In an arrangement, the crown region 43,
intermediate region 48
and frontal region 44 of the head engagement device may be integrally formed
from a
single plate of material.
The intermediate region 48 of the head engagement device may be configured
such that it
performs an additional function beyond connecting the crown region 43 to the
frontal
region 44. In particular, in the event of an impact towards the front of the
helmet 1, the
intermediate region 48 may assist in preventing the forehead of a wearer of
the helmet
from contacting the frontal region of the outer shell 2. For example, this may
reduce the
tendency for the front of the head of the wearer to pass between two straps 20
in an
arrangement such as that depicted in Fig. 5.
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It should be appreciated that such an arrangement is not essential. The straps
20 used to
form a head mount may be positioned to avoid such a potential problem in any
event. For
example, with a sufficient number of straps 20, and/or with sufficiently wide
straps, the
problem may be avoided or minimised. Alternatively or additionally a strap 20
may be
provided that extends from the front of the helmet.
In an arrangement, as depicted in Fig. 11, although the crown region 43 of the
head
engagement device 40 is provided on the side of the head mount, such as straps
20, that
faces the head of the wearer of the helmet 1, the frontal region 48 may be
provided on the
opposite side of the head ring 30. Accordingly, such an arrangement may be
configured
such that the head ring 30 is positioned between the forehead of the wearer of
the helmet
and the frontal region 48 of the head engagement device.
Such an arrangement may be beneficial if the head ring 30, at least in the
region of the
forehead, is relatively soft and/or flexible. In such an arrangement, the low
friction
interface between the frontal region 48 of the head engagement device 40 and
the part of
the head ring 30 adjacent the wearer's forehead will enable movement of the
head ring 30,
and therefore the forehead of the wearer, relative to the front region of the
outer shell 2.
As shown, the frontal region 48 of the head engagement device 40 may be
connected to the
head ring 30 by connectors 49. Such connectors may be similar to those
discussed above
or another suitable form of connector that permits relative movement between
the
connected components.
As shown in Figs. 12 and 13, one or more pads 66, 67 may be provided to the
helmet 1.
.. For example, in a helmet of any of the configurations discussed above that
includes a
frontal region 44 of the head engagement device 40, a front pad 66 may be
positioned to be
adjacent the forehead of the wearer of the helmet. Depending on the
configuration of the
helmet 1, the front pad may be connected to one or more of the head ring 30,
the frontal
region 44 of the head engagement device 40 and the out shell 2.
For example, the front pad 66 may be directly connected to the frontal region
44 of the
head engagement device 40 in an arrangement in which the frontal region 44 of
the head
engagement device 40 is provided between the head ring 30 and the forehead of
the wearer
of the helmet. In such an arrangement, the frontal region of 44 of the head
engagement
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device 40 may include projections or hooks 68 that may engage with the front
pad 66.
Alternatively or additionally, the front pad 66 may be connected to the head
ring 30 by
way of elastic connectors 69 that engage with hooks or projections 70 formed
on the head
ring 30. In such a configuration, the elastic connectors 69 are configured to
be able to
stretch sufficiently that the front pad 66 is able to move relative to the
head ring 30.
In an arrangement such as that depicted in Fig. 11, in which part of the head
ring 30 is
provided between the forehead of the wearer of the helmet and the frontal
region 48 of the
head engagement device 40, the front pad may be connected directly to the head
ring 30.
Alternatively or additionally, it may be connected by elastic connectors to
the outer shell 2
and/or the frontal region 48 of the head engagement device 40.
In an arrangement, one or more pads 67 may be provided on other parts of the
head
engagement device 40, for example on a crown region 43 of the head engagement
device
40. Such pads 67 may function to improve the comfort for the wearer of the
helmet and/or
to provide separation of the head engagement device 40 from the head of the
wearer,
promoting ventilation. As shown in Fig. 12, the pads 67 may be positioned such
that they
do not overlap locations at which connectors 45 are provided, for example, to
connect the
head engagement device 40 to the head mount. Alternatively or additionally,
one or more
pads 67 may be positioned to cover the connectors 45.
As shown in Fig. 12, one or more holes 43 may be provided in the head
engagement device
40. Such holes may promote ventilation between the head of the wearer and the
gap 21
between the head mount 20 and the outer shell 2.
As discussed above, the head engagement device 40 may also include one or more
holes 41
used to engage with connectors. It should be appreciated that the head
engagement device
40 may therefore be provided with holes that may function either to provide
ventilation or
to engage with a connector. Alternatively, different holes may be provided for
specific
functions.
It should also be appreciated that, where holes 41 are provided for engagement
with
connectors, a head engagement device 40 may be provided with holes 41 in the
locations
necessary for engagement with the connectors to fit the head engagement device
40 within
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a specific design of helmet. Alternatively, the head engagement device 40 may
be
provided with a plurality of holes 41 positioned to enable the engagement
device 40 to be
installed in any of a plurality of helmet designs and/or helmet sizes.
In an arrangement of a helmet such as any of those discussed above in which
the head
mount comprises a plurality of straps 20 and a head ring 30 that at least
partially surrounds
the head of a wearer of the helmet, a head engagement device support 80 may be
provided
that may improve the performance of the helmet. In particular, the head
engagement
device support 80 may be configured to reduce the tendency of the head
engagement
device 40 to pass through gaps between adjacent straps 20 and/or the head ring
30 of the
head mount into the air gap 21 between the head mount and the outer shell
during an
impact. When this occurs, it may undesirably reduce the ability of the head
engagement
device 40 to rotate relative to the head mount.
As is explained in further detail below, the head engagement device support 80
may be
provided as a separate component from the head mount. The helmet may therefore
be
configured such that loading from a radial impact is predominantly or entirely
supported
by the head mount, with the head engagement device support 80 predominantly
being
provided to improve the performance under an oblique impact. For example, the
head
engagement device support 80 may be added to an existing helmet design that
already has
satisfactory performance for radial impact provided by its head mount. It will
be
appreciated, however, that in some arrangements the head engagement device
support 80
may be configured to contribute to the performance of the helmet for radial
impact.
In an arrangement, the head engagement device support 80 may be connected to
at least
one of the straps 20 of the head mount. In particular, as shown in Figs. 14
and 15, the head
engagement device support 80 may include a crown section 81 that is connected
to at least
one of the straps 20 at a location corresponding to the top of the head of the
wearer of the
helmet. The head engagement device support 80 further includes at least one
limb section
82 that extends from the crown section 81 to the head ring 30 and is connected
to the head
ring.
The limb section 82 may be connected to the head ring 30 at a location between
two straps
20 of the head mount, as shown in Fig. 15 for example. The limb section 82 of
the head
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engagement device support 80 may therefore function to support the head
engagement
device (for clarity not shown in Fig. 15) namely inhibit the movement of the
head
engagement device 40 through the gaps between the straps 20. This may prevent
the head
engagement device 40 from having its motion restricted, namely enabling the
head
engagement device 40 to rotate relative to the head mount.
In an arrangement such as that depicted in Figs. 14 and 15, the head
engagement device
support 80 may have two limb sections 82. When installed in a helmet 1, the
two limb
sections 82 of the head engagement device support 80 may be connected to the
head ring
30 at locations corresponding to respective sides of the head of the wearer of
the helmet.
Such an arrangement may improve the performance of the helmet for oblique
impacts on
the side of the helmet.
In another arrangement, depicted in Figs. 16 and 17, the head engagement
device support
80 includes three limb sections 82 that, when installed within a helmet, are
connected to
the head ring 30 at respective locations corresponding to the sides and the
front of the head
of a wearer of the helmet. In a variation of such an arrangement, the head
engagement
device support 80 may be installed such that the three limb sections 82 are
connected to
respective locations on the head ring 30 at the sides and the back of the head
of a wearer of
the helmet.
In a further variation, as depicted in Fig. 18, the head engagement device
support 80 may
have four limb sections 82, configured to be connected to the head ring 30 at
respective
locations corresponding to the two sides, the front and the back of the head
of a wearer of
the helmet. In general, it should be appreciated that the head engagement
device support
80 may have any number of limb sections connected to respective locations on
the head
ring 30.
The crown section 81 of the head engagement support 80 may be connected to one
or more
of the straps at a location corresponding to the top of the head of a wearer
of the helmet by
any convenient means. In the arrangement depicted in Figs. 14 to 17, for
example, the
crown section 81 includes at least one slot 85 through which a strap 20 may
pass in order
that the head engagement device support 80 is connected to the strap 20. In
arrangements
such as that depicted in Figs. 14 to 17, the slots 85 in the crown section 81
of the head
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engagement device support 80 may be provided in pairs. With such an
arrangement, a
strap 20 may pass from a first side of the head engagement device support 80
through a
first slot 85 of a pair to the opposite side of the head engagement device
support 80 and
then back through a second slot 85 of the pair to return to the first side of
the head
engagement device support 80 providing a robust connection.
Figs. 19 and 20 depict an alternative arrangement for connecting the crown
section 81 of
the head engagement device support 80 to the straps 20 of the head mount. In
particular,
as shown, the crown section 81 of the head engagement device support 80
includes an
extension 87 that can be folded around at least one of the straps 20 and
connected back to
the remainder of the crown section 81. In the example depicted in Figs. 19 and
20, the
extension 87 of the crown section 81 has a shape matching that of the crown
section 81. It
will be appreciated however, that this is not essential. The extension 87 of
the crown
section 81 may be connected to the crown section 81 by way of one or more
suitable
connectors 88. The connectors 88 may, for example, be formed from hook and
loop
material, a snap-fit connector and/or adhesive.
The limb sections 82 of the head engagement device support 80 may be connected
to the
head ring 30 by any suitable means. In an arrangement, as depicted in Fig. 21,
an end 90
of the limb section 82 may extend around a portion of the head ring 30 and
connect to
itself. The connection of the end 90 of the limb section 82 to itself may be
implemented by
the provision of a connector 91. The connector 91 may be of any suitable form
including,
for example, hook and loop material, a snap-fit connector and/or adhesive.
Alternatively or additionally, the limb section 82 of the head engagement
device support
80 may be directly connected to the head ring by, for example, a snap-fit
connection and/or
adhesive.
In an arrangement of a helmet with a head engagement device support 80, the
head
engagement device 40 may be connected to the head engagement device support 80
either
as the sole means of connection of the head engagement device 40 to the helmet
or in
addition to another connection arrangement. Any connectors between the head
engagement device 40 and the head engagement device support 80 may be
configured such
that the head engagement device 40 can move relative to the head engagement
device
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support 80 such that, under an impact to the helmet, the head engagement
device 40 can
slide relative to the head engagement device support 80 and the head mount.
As shown in Fig. 22, in an arrangement, a connector 95 provided to connect the
head
.. engagement device 40 to the head engagement device support 80 may be
provided on the
crown section 81 of the head engagement device support 80.
Fig. 23 depicts an alternative arrangement in which plural connectors 95
between the head
engagement device 40 and the head engagement device support 80 are
additionally
provided at the ends of the limb sections 82 at the respective locations at
which the limb
sections 82 are connected to the head ring 30.
It will be appreciated that other arrangements of connectors are possible. For
example, the
connectors 95 may only be provided at the ends of the limb sections 82, with
no connector
at the crown section 81. Alternatively or additionally, connectors may be
provided on
some of the limb sections 82 and not others. Alternatively or additionally,
connectors 95
provided on limb sections 82 may be provided at locations other than the ends
of the limb
sections at the locations at which the limb sections 82 connect to the head
ring 30.
As shown in Fig. 24, once the head engagement device 40 is installed within
the helmet 1,
for example connected to the head engagement device support 80, it may
substantially
overlie the head engagement device support 80 and conceal the connectors 95.
In other
arrangements, at least a part of the head engagement device support 80 may be
visible.
In an arrangement, a connector 95 used to connect the head engagement device
40 to the
head engagement device support 80 may be formed from an elastically deformable
material in order to enable movement of the head engagement device 40 relative
to the
head engagement device support 80 while remaining connected.
In an arrangement, as depicted in Fig. 27, for example, the connector 95 may
be formed
from a sheet of elastically deformable material 96 arranged such that an inner
region 97 of
the sheet of elastically deformable material is connected to one of the head
engagement
device support 80 and the head engagement device 40 and such that a peripheral
region 98
of the sheet of elastically deformable material is connected to the other of
the head
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engagement device support 80 and the head engagement device 40. Deformation of
the
sheet of elastically deformable material enables the inner region to move
relative to the
peripheral region, in turn enabling the head engagement device support 40 to
move relative
to the head engagement device support 80. It will be appreciated that other
forms of
connector that enable movement between the head engagement device 40 and the
head
engagement device support 80 may be used.
In order to ensure that the head engagement device 40 can move relative to the
head
engagement device support 80 under an impact, a low friction interface may be
provided
between the head engagement device 40 and the head engagement device support
80 in a
similar manner to that described above between the head engagement device 40
and the
head mount.
In an arrangement, at least the outer surface of the head engagement device
support 80 may
be formed from a fabric or felt, selected to enable sliding of the head
engagement device
40 against it. Fig. 25 schematically depicts, in cross section, a head
engagement device
support 80. As shown, it may have a laminated structure including a layer of
foam 102
between two layers of fabric or felt 101. The layers may be joined by adhesive
or by heat
welding. The layer of foam 102 may be provided to increase the stiffness of
the head
engagement device support 80. Accordingly, the material of the foam layer 102
may be
selected to be stiffer than the layers of fabric or felt 101. In an example,
the layers of
fabric or felt 101 may be formed from brushed Nylon. In an example, the foam
layer 102
may be formed from polyethylene (PE) foam and/or polyurethane (PU) foam, in
which
case the characteristics of the foam, such as the density, may be selected to
provide a
desired stiffness.
In an arrangement, in place of the foam layer, the head engagement device
support 80 may
include a plastic plate 103 between two layers of fabric or felt 101. The
plastic plate 103
within the head engagement device support 80 may be formed from any one of the
materials discussed above as being suitable for forming the head engagement
device 40. It
will be appreciated, however, that in a particular helmet, different materials
and/or
different thicknesses of material may be used for the head engagement device
40 and the
plate 103 within the head engagement device support 80. As depicted in Fig.
26, in such
an arrangement, the stiffening plate 103 provided within the head engagement
device
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support 80 may only correspond to a part of the shape of the head engagement
device
support 80, for example a central region.
The purpose of helmet layers or components of a helmet, that move or slide
relative to
each other, such as those discussed above including the head mount and head
engagement
device, may be to redirect energy of an impact that would otherwise be
transferred to the
head the wearer. This may improve the protection afforded to the wearer
against a
tangential component of the impact energy. A tangential component of the
impact energy
would normally result in rotational acceleration of the head of the wearer. It
is well know
that such rotation can cause brain injury. It has been shown that helmets with
layers or
components that move relative to each other can reduce the rotational
acceleration of the
head of the wearer. A typical reduction may be roughly 25% but reductions as
high as
90% may be possible in some instances.
Preferably, relative movement between helmet layers results in a total shift
amount of at
least 0.5 cm between an outermost helmet layer and an inner most helmet layer,
more
preferably at least lcm, more preferably still at least 1.5cm. Preferably the
relative
movement can occur in any direction, e.g. in a circumferential direction
around the helmet,
left to right, front to back and any direction in between.
Regardless of how helmet layers or components are configured to move relative
to each
other, it is preferable that the relative movement, such as sliding, is able
to occur under
forces typical of an impact for which the helmet is designed (for example an
impact that is
expected to be survivable for the wearer). Such forces are significantly
higher than forces
that a helmet may be subject to during normal use. Impact forces tend to
compress layers
of the helmet together, increasing the reaction force between components and
thus
increasing frictional forces. Where helmets are configured to have layers
sliding relative to
each other the interface between them may need to be configured to enable
sliding even
under the effect of the high reaction forces experienced between them under an
impact.
Helmets as described above may be used in various activities. These activities
include
combat and industrial purposes, such as protective helmets for soldiers and
hard-hats or
helmets used by builders, mine-workers, or operators of industrial machinery
for example.
Helmets, are also common in sporting activities. For example, protective
helmets may be
27
CA 03221588 2023-11-24
WO 2022/268647 PCT/EP2022/066500
used in ice hockey, cycling, motorcycling, motor-car racing, skiing, snow-
boarding,
skating, skateboarding, equestrian activities, American football, baseball,
rugby, soccer,
cricket, lacrosse, climbing, golf, airsoft, roller derby and paintballing.
Examples of injuries that may be prevented or mitigated by the helmets
described above
include Mild Traumatic Brain Injuries (MTBI) such as concussion, and Severe
Traumatic
Brain Injuries (STBI) such as subdural haematomas (SDH), bleeding as a
consequence of
blood vessels rapturing, and diffuse axonal injuries (DAI), which can be
summarized as
nerve fibres being over stretched as a consequence of high shear deformations
in the brain
.. tissue.
Depending on the characteristics of the rotational component of an impact,
such as the
duration, amplitude and rate of increase, either concussion, SDH, DAI or a
combination of
these injuries can be suffered. Generally speaking, SDH occur in the case of
accelerations
of short duration and great amplitude, while DAI occur in the case of longer
and more
widespread acceleration loads.
Variations of the above described examples are possible in light of the above
teachings. It
is to be understood that the invention may be practiced otherwise and
specifically
described herein without departing from the spirit and scope of the invention.
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