U.S. patent application number 17/616549 was filed with the patent office on 2022-07-28 for helmet.
This patent application is currently assigned to HEXR LTD. The applicant listed for this patent is HEXR LTD. Invention is credited to James COOK, Henry NEILSON.
Application Number | 20220232924 17/616549 |
Document ID | / |
Family ID | 1000006302702 |
Filed Date | 2022-07-28 |
United States Patent
Application |
20220232924 |
Kind Code |
A1 |
COOK; James ; et
al. |
July 28, 2022 |
HELMET
Abstract
A helmet (100) including an impact absorbing layer (102), an
outer shell (104) and a connector (106, 114). The outer shell is
mounted on the outer surface of the impact absorbing layer. The
connector connects the outer shell to the impact absorbing layer,
to retain the outer shell on the impact absorbing layer. The
connector is also arranged to allow the outer shell to separate
from the impact absorbing layer when the helmet is subject to an
impact.
Inventors: |
COOK; James; (London,
GB) ; NEILSON; Henry; (London, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HEXR LTD |
London |
|
GB |
|
|
Assignee: |
HEXR LTD
London
GB
|
Family ID: |
1000006302702 |
Appl. No.: |
17/616549 |
Filed: |
June 5, 2020 |
PCT Filed: |
June 5, 2020 |
PCT NO: |
PCT/GB2020/051378 |
371 Date: |
December 3, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A42B 3/064 20130101 |
International
Class: |
A42B 3/06 20060101
A42B003/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2019 |
GB |
1908090.2 |
Claims
1. A helmet comprising: an impact absorbing layer; an outer shell
mounted on the outer surface of the impact absorbing layer; and a
connector which connects the outer shell to the impact absorbing
layer to retain the outer shell on the impact absorbing layer;
wherein the connector is arranged to allow the outer shell to
separate from the impact absorbing layer when the helmet is subject
to an impact.
2. The helmet as claimed in claim 1, wherein the impact absorbing
layer comprises a hollow cell structure.
3. The helmet as claimed in claim 1, wherein the outer shell is
formed from a rigid material.
4. The helmet as claimed in claim 1, wherein the outer shell has a
thickness of less than 6 mm, less than 4 mm, e.g. less than 2 mm,
e.g. less than 0.5 mm.
5. The helmet as claimed in claim 1, wherein the connector is
arranged to allow the outer shell to separate from the impact
absorbing layer when the helmet is subject to an impact having a
particular force.
6. The helmet as claimed in claim 1, wherein the connector is
located along an axis of symmetry of the helmet.
7. The helmet as claimed in claim 1, wherein the connector is
located at the front of the helmet.
8. The helmet as claimed in claim 1, wherein the connector
comprises a discrete component from the outer shell and the impact
absorbing layer.
9. The helmet as claimed in claim 1, wherein at least a portion of
the connector is arranged to detach from the impact absorbing layer
and/or the outer shell when the helmet is subject to an impact.
10. The helmet as claimed in claim 1, wherein the connector
comprises a plug which extends between the outer shell and the
impact absorbing layer.
11. The helmet as claimed in claim 10, wherein the outer shell
comprises an aperture for receiving the plug.
12. The helmet as claimed in claim 10, wherein the connector
comprises a socket for receiving the plug of the connector.
13. The helmet as claimed in claim 12, wherein the socket is formed
on or attached to the outer surface of the impact absorbing
layer.
14. The helmet as claimed in claim 12, wherein the plug and the
socket attach together via a push fit.
15. The helmet as claimed in claim 10, wherein the plug comprises
an outer head having dimension(s) greater than the corresponding
dimension(s) of the aperture.
16. The helmet as claimed in claim 1, wherein the connector
comprises a projection and that is integral to the impact absorbing
layer, wherein the protection is attached to the main body of the
impact absorbing layer by a flexible portion.
17. (canceled)
18. The helmet as claimed in claim 16, wherein the impact absorbing
layer comprises a cavity arranged to receive the projection.
19. The helmet as claimed in claim 16, wherein the outer shell
comprises an aperture for receiving the projection.
20. The helmet as claimed in claim 1, wherein the impact absorbing
layer comprises at least one groove formed therein, wherein the
outer shell comprises at least one inwardly projecting ridge, and
wherein the at least one ridge is arranged to engage with the at
least one groove when the outer shell is mounted on the impact
absorbing layer, and wherein the at least one ridge and the at
least one groove are arranged such that a particular force is
required to remove the at least one ridge from the at least one
groove.
21. (canceled)
22. The helmet as claimed in claim 1, wherein the connector extends
in a radial direction to the impact absorbing layer.
Description
[0001] This nonprovisional application is a National Stage of
International Application No. PCT/GB2020/051378, which was filed on
Jun. 5, 2020, and which claims priority to Great Britain Patent
Application No. 1908090.2, which was filed in Great Britain on Jun.
6, 2019, and which are both herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] This invention relates to a helmet, in particular a helmet
having a detachable outer shell.
Description of the Background Art
[0003] Head injuries, which can be incurred as a result of
participation in sports such as cycling, horse riding or rock
climbing, are a common cause of serious brain injuries. Impact
protection is therefore important in preventing brain injuries as a
result of impacts to the head. Head protection, in the form of
helmets, is designed to reduce the forces experienced by a user's
head during an impact. Typically, a helmet comprises at least one
impact absorbing layer which is designed to absorb a portion of the
forces to which the helmet is subjected during an impact.
[0004] However, a helmet often does not provide adequate protection
during an oblique impact which subjects the helmet to significant
tangential forces. Oblique impacts are common, as it is rare for an
impact to occur directly along the normal to the outer surface of
the helmet with no additional components in other directions.
Tangential forces result in the rotational acceleration of the
brain, which has been linked to bridging vein rupture. In turn,
this may be responsible for subdural haematomas, and diffuse axonal
injuries.
SUMMARY OF THE INVENTION
[0005] It is an aim of the present invention to provide an improved
helmet.
[0006] When viewed from a first aspect the present invention
provides a helmet comprising:
[0007] an impact absorbing layer;
[0008] an outer shell mounted on the outer surface of the impact
absorbing layer; and
[0009] a connector which connects the outer shell to the impact
absorbing layer to retain the outer shell on the impact absorbing
layer;
[0010] wherein the connector is arranged to allow the outer shell
to separate from the impact absorbing layer when the helmet is
subject to an impact.
[0011] This invention relates to a helmet including an impact
absorbing layer and an outer shell, which are connected together by
a connector, e.g. to retain the outer shell on the impact absorbing
layer during normal use. When the helmet is subject to an impact
(and thus an external force acts on the helmet) the connector is
arranged such that it allows the outer shell to separate from the
impact absorbing layer (i.e. be moved to a different position from
that in which the outer shell is mounted on the impact absorbing
layer and the connector is connecting them). For example, the outer
shell may be configured such that it is able to rotate about the
impact absorbing layer when not connected to the impact absorbing
layer by the connector.
[0012] The skilled person will appreciate that owing the way in
which the outer shell is detachably connected to the impact
absorbing layer via the connector, the outer shell is able to move,
and for example rotate, about the outer surface of the impact
absorbing layer when the outer shell has separated from the impact
absorbing layer (owing to no longer being held in place by the
connector). Therefore, when the helmet is subject to an impact that
involves at least a tangential component (i.e. that is not solely
along the normal direction to the outer surface of the helmet), at
least a portion of the tangential forces produced by the impact may
act to rotate the outer shell. This helps to reduce the rotation of
the head of the user and thus the transfer of tangential forces
from the impact. This is because the user's head (e.g. with the
impact absorbing layer still attached thereto) may able to
translate (e.g. slide or rotate) within the outer shell instead of
being subject to the tangential forces itself.
[0013] When the tangential forces experienced by the head are
reduced (thus reducing the rotational acceleration experienced by
the head), the risk of injuries such as bridging vein rupture are
decreased. Reducing the tangential forces experienced by a user's
head further reduces the risk of neck injuries caused by
over-rotation of the head with respect to the neck.
[0014] In at least preferred embodiments, the impact absorbing
layer is designed to provide a user's head with a degree of
protection against bulk forces exerted in an impact. Thus
preferably, the impact absorbing layer is arranged to absorb at
least a portion of the normal component of the forces exerted on
the helmet during an impact.
[0015] The impact absorbing layer may be formed from any suitable
and desired material, such as expanded polystyrene. In a preferred
set of embodiments, the impact absorbing layer comprises a hollow
cell structure, e.g. comprising a plurality of hexagonal cells (in
cross section). Preferably, at least a plurality of the cells
tessellate with each other. For example, the impact absorbing layer
structure may comprise a micro-truss lattice or an out-of-plane
honeycomb. The impact absorbing layer may further comprise a rim,
e.g. around the edge (below) the hollow cell structure.
[0016] Typically, in conventional helmets comprising an outer
shell, the outer shell may be provided predominately as an
aesthetic feature used to improve the appearance of the helmet.
Such outer shells are typically not connected as a separate,
discrete part of the helmet (thus contrasting with the outer shell
of the present invention). Instead conventional helmets may be
manufactured in moulds, into which the material forming the impact
absorbing layer is injected. In the present invention, the
Applicant has appreciated that the outer shell may also help to
reduce the rotation of the head of the user when the helmet is
subject to an impact. Preferably the outer shell is formed from a
rigid material, such as a thermoplastic, e.g. polycarbonate, or
carbon fibre, or a composite material; however, it could be made
from any suitable and desired material. Preferable materials for
forming the outer shell have high strength to weight ratios.
[0017] In a preferred set of embodiments, the outer shell has a
thickness that is significantly less than a thickness of the impact
absorbing layer. The outer shell may thus comprise a membrane, e.g.
at least partly covering the impact absorbing layer. Thus, while
the outer shell is designed to detach from the impact absorbing
layer when subject to an impact, the outer shell may itself not be
designed to absorb the force of the impact. Preferably, the outer
shell has a thickness (e.g. in the normal direction) of less than 6
mm, e.g. less than 4 mm, e.g. less than 2 mm, e.g. less than 0.5 mm
Different outer shell thickness may be advantageous for different
types of helmets, e.g. motorcyclist helmets may preferably have a
thicker outer shell (e.g. 6 mm), whereas bicycle helmets may have a
thinner outer shell (e.g. less than 4 mm).
[0018] Preferably the impact absorbing layer has a thickness (e.g.
in the normal direction) of between 10 mm and 50 mm, e.g. between
20 mm and 30 mm. Different impact absorbing layer thickness may be
appropriate for different types of helmets, e.g. motorcyclist
helmets may preferably have a thicker impact absorbing layer (e.g.
between 20 mm and 50 mm), whereas bicycle helmets may have a
thinner impact absorbing layer (e.g. between 10 mm and 30 mm).
[0019] In a preferred set of embodiments, the outer shell covers at
least 60% of the surface area of the outer surface of the impact
absorbing layer, e.g. at least 70%, e.g. at least 80%. The outer
shell preferably covers the impact absorbing layer at one or more,
e.g. all, sites on the helmet which may experience an impact. The
outer shell may comprise one or more vent apertures to allow
airflow. The outer shell may not extend over the rim of the impact
absorbing layer, when provided. Thus for example, the outer shell
may only extend over the outer surface of the hollow cell
structure. However, in other examples the shell extends at least
partly over the rim.
[0020] In a set of embodiments, the outer shell has a smooth outer
surface, e.g. in which the impact absorbing layer is formed from a
plurality of cells. In a set of embodiments, the inner surface of
the outer shell is smooth. Such embodiments may be advantageous as
providing smooth surfaces enables the outer shell to rotate over
the impact absorbing layer with a minimized resistance upon
impact.
[0021] The connecter is designed to retain the outer shell on the
impact absorbing layer (e.g. during normal use), and to allow the
outer shell to separate from the impact absorbing layer during an
impact. This may allow the outer shell to move, e.g. rotate, about
the outer surface of the impact absorbing layer. This may be
achieved in any suitable or desired way. For example, the connector
may be arranged to retain the outer shell in position on the impact
absorbing layer when weaker forces act on the helmet (e.g. as would
be expected in normal use), and allow the outer shell to separate
from the outer shell when larger forces act on the helmet, e.g. as
the result of an impact. Preferably the connector extends in a
radial direction, e.g. perpendicular, to the surface of the impact
absorbing layer (e.g. parallel to the walls of the plurality of
cells) and/or perpendicular to the surface of the outer shell.
[0022] In a set of embodiments, the connector is arranged to allow
the outer shell to separate from the impact absorbing layer when
the (e.g. outer shell of the) helmet is subject to an impact having
a particular (e.g. predetermined) force (e.g. an oblique force).
This helps to retain the outer shell on the impact absorbing layer
during normal use and to separate from the impact absorbing layer
when subject to an impact. The particular force required for the
connector to allow the outer shell to separate from the impact
absorbing layer may be chosen to have any suitable and desired
value (e.g. such that the outer shell only separates from the
impact absorbing layer as the result of a sufficiently large
impact). In one embodiment the particular (e.g. predetermined)
force is between 10 and 100 N, e.g. between 30 N and 70 N, e.g.
approximately 50 N. The particular force may, for example be chosen
such that it reflects the lowest range of forces acting on the
helmet which may cause an injury.
[0023] The connector may be located at any suitable and desired
position on the helmet. However, preferably the connector is
located along an axis of symmetry of the helmet, e.g. along the mid
plane of the helmet extending from the front to the rear of the
helmet. In a set of embodiments, the connector is located at the
front of the helmet. Positioning the connector at the front of the
helmet may be particularly useful in aiding the detachment of the
outer shell in an oblique impact, particularly for impacts that are
offset from the central axis of symmetry and thus the front of the
helmet.
[0024] The connector may have any suitable and desired form, e.g.
such that it is arranged to allow the outer shell to separate from
the impact absorbing layer when the helmet is subject to an impact
(e.g. having a force greater than a particular value e.g.
approximately 50 N). In a set of embodiments, the connector
comprises a discrete component from the outer shell and the impact
absorbing layer. Thus preferably at least a portion (e.g. the
discrete component) of the connector is arranged to detach from the
impact absorbing layer and/or the outer shell when the helmet is
subject to an impact, e.g. such that the at least a portion (e.g.
the discrete component) of the connector is no longer in contact
with the rest of the helmet, thus allowing the outer shell to be
separated from the impact absorbing layer.
[0025] In one set of embodiments the connector comprises a plug
which extends between (and, e.g., is attached to both) the outer
shell and the impact absorbing layer. Preferably, the outer shell
comprises an aperture for receiving the plug. Thus, for example,
the plug extends through the aperture and attaches to (e.g. a
socket of) the impact absorbing layer. The plug therefore may be
accessible from the outside of the outer shell. This may allow the
plug to be easily removed to interchange the plug and/or the outer
shell. Interchanging the plug or the outer shell is particular
advantageous if either is damaged accidently or for aesthetic
reasons.
[0026] Preferably the plug comprises an outer head having
dimension(s) greater than the corresponding dimension(s) of the
aperture. The outer head of the plug may therefore cover (e.g.
encase) a portion of the outside of the outer shell. This may
further aid easier removal of the plug to interchange the plug
and/or the outer shell.
[0027] The plug may attach to the impact absorbing layer in any
suitable and desired way. The plug may attach directly to the
impact absorbing layer. For example, in embodiments in which the
impact absorbing layer comprises a hollow cell structure (e.g.
comprising a plurality of cells), the plug may attach directly into
a cell of the hollow cell structure of the impact absorbing
layer.
[0028] In a preferred set of embodiments, the connector comprises a
socket (e.g. clip) for receiving the plug of the connector.
Preferably the socket is formed on or attached to the outer surface
of the impact absorbing layer. Thus, when the outer shell is
mounted on and retained to impact absorbing layer, the plug is
located in the socket. Preferably, when the helmet is subject to an
impact, the plug is arranged to be removed from the socket, such
that this allows the outer shell to separate from the impact
absorbing layer.
[0029] In one set of embodiments, the connector is an integrally
formed part of the helmet (e.g. of the outer shell and/or the
impact absorbing layer). For example, the outer shell and the
impact absorbing layer may comprise complementary (e.g. male and
female) parts which (e.g. fit together to) form the connector.
Thus, for example, the outer shell may comprise a female (or male)
member and the impact absorbing layer may comprise a corresponding
male (or female) member which connect together to attach the outer
shell to the impact absorbing layer. As outlined above, for
example, the male member may comprise a plug and the female member
may comprise a complementary socket.
[0030] In a set of embodiments, the connector comprises a (e.g.
hinged) projection (e.g. a projecting latch). Preferably the
projection is integral to (comprises part of) the impact absorbing
layer. Preferably, the projection is attached (e.g. integral) to
the main body of the impact absorbing layer by a flexible (e.g.
hinged) portion. Preferably the flexible portion is formed from the
same material as (e.g. is integral to) the impact absorbing
layer.
[0031] The flexible (e.g. hinged) portion may be formed by a
portion of material (e.g. a "living hinge") that is thinner than
the surrounding material (e.g. of the impact absorbing later and/or
the projection). The flexible portion allows the projection to bend
and/or deform (e.g. relative to the impact absorbing layer) when a
force is applied, e.g. without fracturing and/or rupturing the
projection or its attachment to the main body of the impact
absorbing layer (via the flexible portion).
[0032] In a set of embodiments, the impact absorbing layer
comprises a cavity arranged to receive the projection, e.g. when
the projection bends or deforms (e.g. via the flexible portion)
relative to the main body of the impact absorbing layer. This may
happen, for example, when a force is applied to the projection
(e.g. via the outer shell). Preferably the projection is arranged
to bend and/or deform relative to the main body of the impact
absorbing layer, to allow the outer shell to separate from the
impact absorbing layer when the helmet is subject to an impact.
Thus, preferably, in normal use of the helmet, the cavity is empty
and the projection substantially does not protrude into the
cavity.
[0033] Preferably, the outer shell comprises an aperture for
receiving the projection (e.g. in the manner of a latch). The
projection and the aperture are preferably arranged such that the
projection extends through the aperture, e.g. when no force is
applied to the projection. Preferably the projection and the
aperture are arranged to retain the outer shell on the impact
absorbing layer.
[0034] Preferably the projection and the aperture are arranged such
that when a force is applied to the projection (e.g. as a result of
a force being applied to the outer shell) the projection and the
aperture move relative to (e.g. apart from) each other, allowing
the outer shell to move relative to the impact absorbing layer.
This may be owing to the projection being pushed into the cavity or
the outer shell flexing away from the projection. Preferably this
results in the projection no longer extending through the aperture
in the outer shell.
[0035] This arrangement may help to retain the outer shell in a
desired position on the impact absorbing structure during normal
use, while allowing (e.g. translational) movement of the outer
shell over the impact absorbing layer when the projection has been
moved into the cavity in the impact absorbing layer (e.g. owing to
a force being applied to the projection during an accident or by
intentional means by a user, such as to remove the outer shell from
the impact absorbing layer).
[0036] In any of the embodiments described herein, the components
of the connector may attach to each other (and/or to the outer
shell and/or impact absorbing layer) in any suitable or desired
way, e.g. to provide them with an attachment requiring a particular
separation force (e.g. the particular force required to separate
the outer shell from the impact absorbing layer as outlined
above).
[0037] For example, the plug and the (e.g. socket of the) impact
absorbing layer may attach together via a push (e.g. friction) fit.
The push fit may be determined (e.g. solely) by the dimensions of
the plug (and, e.g., the socket). However, in one embodiment, the
plug and/or socket comprise one or more grips, ridges or latches.
The grips, ridges or latches may help to control (e.g. increase)
the friction therebetween and thus the force required to be exerted
for the connector to allow the outer shell to separate from the
impact absorbing layer when the helmet is subject to an impact.
[0038] The connector may be formed from any suitable and desired
material. Preferably the connector (e.g. the plug and/or socket) is
formed from a rigid material such as plastic, e.g. a thermoplastic,
e.g. thermoplastic polyurethane (TPU), or a polyamide (Nylon), e.g.
laser sintered polyamide 11, or acrylonitrile butadiene styrene
(ABS). The connector (e.g. the plug and/or socket) may be formed of
multiple parts which may be fabricated from different materials, as
appropriate. For example, as outlined above, at least part of the
connector may be integrally formed with (and thus preferably formed
from the same material from) the impact absorbing layer.
[0039] In some embodiments the connector is arranged to separate
into distinct parts or break when the helmet is subjected to an
impact, rather than to deform and absorb energy when subjected to
an impact. Preferably the plug is weaker than the outer shell, such
that the connector may detach before the shell fractures during an
impact.
[0040] The connector may be arranged to allow the outer shell to
separate from the impact absorbing layer as a result of an impact
in any suitable and desired way. Furthermore, the outer shell and
the impact absorbing layer may be arranged to separate from each
other in any suitable and desired way. In a preferred embodiment,
e.g. when the helmet is subject to an oblique impact (such that
tangential and radial forces are exerted on the helmet), the outer
shell is arranged to be displaced relative to (e.g. rotated about)
the impact absorbing layer. Preferably the displacement of the
outer shell causes the connector to disconnect (e.g. the plug to be
detached), e.g. owing to shearing forces.
[0041] The outer shell may be displaced relative to the impact
absorbing layer in any suitable and desired way. Preferably the
outer shell is arranged to translate (e.g. slide or rotate)
relative to the impact absorbing layer when the helmet is subject
to an impact. Thus, preferably, apart from the connector (and, e.g.
any further features (e.g. as outlined herein) that help to locate
the outer shell relative to the impact absorbing layer), the outer
shell is not fixed (e.g. glued, taped or attached permanently by
connectors) to the impact absorbing layer. This enables the outer
shell to be separated from the impact absorbing layer when the
connector is no longer connecting the outer shell to the impact
absorbing layer. Thus preferably no part which is integral to the
(e.g. inner surface of the) outer shell (e.g. away from the
perimeter of the outer shell) is attached to the impact absorbing
layer.
[0042] When subject to an impact that causes the outer shell to
separate from the impact absorbing layer, preferably the connector
is arranged to allow the outer shell to separate from the impact
absorbing layer within 5 ms of the impact. Preferably the outer
shell and the impact absorbing layer are arranged to move, e.g.
rotate, relative to each other for between 10 and 15 ms when
subject to an impact, e.g. after the outer shell has separated from
the impact absorbing layer.
[0043] While the helmet may comprise only one connector, in a set
of embodiments the helmet comprises a plurality of connectors that
connect the outer shell to the impact absorbing layer. The
plurality of connectors may be identical or different. Preferably
the plurality of connectors are (together) arranged (e.g. together)
to allow the outer shell to separate from the impact absorbing
layer when the helmet is subjected to a particular (e.g.
predetermined) force. Preferably the plurality of connectors are
located in respective different positions on the helmet. For
example, the connectors may be located at particular angles about
the base of the outer shell, e.g. evenly spaced from each
other.
[0044] While the connector preferably provides the principal
connection that connects the outer shell to the impact absorbing
layer to retain the outer shell on the impact absorbing layer, the
helmet may comprise one or more additional features which aid the
(correct) positioning and retention of the outer shell on the
impact absorbing layer. The (e.g. rim of the) impact absorbing
layer may comprise at least one groove or projection formed
therein. In some embodiments the outer shell may comprise at least
one inwardly projecting ridge (e.g. clip).
[0045] Preferably the at least one ridge corresponds (e.g. in
location) to and engages with the at least one groove (or
projection) in the (e.g. rim of the) impact absorbing layer (e.g.
in terms of location and dimensions), such that the ridge is
located in the groove (or on the projection), when the outer shell
is mounted on the impact absorbing layer. The at least one ridge
may thus be located in the at least one groove (when the outer
shell is mounted on the impact absorbing layer), such that there
are additional attachment point(s) between the outer shell and the
impact absorbing layer than just the connector. The interconnecting
ridge(s) and groove(s) (or projection(s)) help to retain the outer
shell in position during general use.
[0046] Preferably, the interconnecting ridge(s) and groove(s) (or
projection(s)) provide a weaker connection between the outer shell
and the impact absorbing layer than is provided by the connector.
During an impact, when the connector disconnects the outer shell
from the impact absorbing layer, the at least one ridge is forced
out of position from its corresponding groove (or projection) such
that the outer shell is able to separate from the impact absorbing
layer.
[0047] Thus, in one embodiment, the ridge(s) and groove(s) (or
projection(s)) are arranged (e.g. interconnected when the outer
shell is mounted on the impact absorbing layer) such that a
particular (e.g. predetermined) force is required to remove the
ridge(s) from the corresponding complementary groove(s) (or
projection(s)). Preferably, this particular (e.g. predetermined)
force is less than the particular (e.g. predetermined) force
required for the connector to allow the outer shell to separate
from the impact absorbing layer when the helmet is subject to an
impact. This helps to ensure that once the force of an impact is
sufficient to disconnect the connector between the outer shell and
the impact absorbing layer, to separate the outer shell from the
impact absorbing layer, the ridge(s) and groove(s) (or
projection(s)) will preferably also detach (or have already
detached) from each other and will preferably not act to provide
any further resistance in retaining the outer shell on the impact
absorbing layer.
[0048] In some embodiments the (e.g. rim of the) impact absorbing
layer comprises at least one ridge and the outer shell comprises at
least one groove (or projection), i.e. the positioning of the ridge
and the groove on the impact absorbing layer and the outer shell
are the opposite way around compared to the arrangement described
above. The features of the ridge(s) and groove(s) (or
projection(s)) outlined herein may apply equally to this
embodiment.
[0049] The one or more grooves (or projections) and ridges may be
located in any suitable and desired positions around the (e.g. rim
of the) impact absorbing layer and the outer shell. In a set of
embodiments, the groove(s) (or projection(s)) are equally spaced
about the (e.g. rim of the) impact absorbing layer. The one or more
ridges are preferably correspondingly located towards (e.g. at) the
bottom edge (e.g. a rim) of the outer shell. For example,
complementary grooves (or projections) and ridges may be located at
the sides and rear of the helmet. Providing a plurality of
interconnecting grooves (or projections) and ridges allows the
shell to be held more securely in position on the impact absorbing
layer, when the outer shell is mounted on the impact absorbing
layer during normal use.
[0050] In one embodiment, e.g. in addition to the ridge(s) and
groove(s) (or projection(s)) outlined above, in order to help
retain the outer shell in position on the impact absorbing layer
during normal use, the impact absorbing layer may comprise at least
one protrusion on its outer surface. When the impact absorbing
layer comprises a plurality of protrusions, preferably the
protrusions are evenly spaced around the outer surface of the
impact absorbing layer. In this embodiment, preferably the outer
shell comprises at least one recess corresponding (and
complementary) to the at least one protrusion of the impact
absorbing layer. Thus, when the outer shell is located on the outer
surface of the impact absorbing layer, the at least one protrusion
on the impact absorbing layer interconnects with the at least one
corresponding recess.
[0051] Preferably, the complementary protrusion(s) and recess(es)
are provided (only) to help locate the outer shell in its correct
position on the impact absorbing layer. Thus preferably, the
complementary protrusion(s) and recess(es) provide a (e.g.
significantly) weaker connection between the outer shell and the
impact absorbing layer than is provided by the connector (and,
e.g., by the complementary groove(s) (or projection(s)) and
ridge(s)). During an impact, when the connector disconnects the
outer shell from the impact absorbing layer, the protrusion(s) and
recess(es) move apart from each other such that the outer shell is
able to separate from the impact absorbing layer.
[0052] Thus, in one embodiment, the complementary protrusion(s) and
recess(es) are arranged such that a particular (e.g. predetermined)
force is required to displace the protrusion(s) from the
complementary recess(es). Preferably, this particular (e.g.
predetermined) force is (e.g. significantly) less than the
particular (e.g. predetermined) force required for the connector to
allow the outer shell to separate from the impact absorbing layer
when the helmet is subject to an impact. This helps to ensure that
once the force of an impact is sufficient to disconnect the
connector between the outer shell and the impact absorbing layer,
to separate the outer shell from the impact absorbing layer, the
complementary protrusion(s) and recess(es) will preferably also be
displaced (or have already been displaced) from each other and will
preferably not act to provide any further resistance in retaining
the outer shell on the impact absorbing layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] An embodiment of the present invention will now be
described, by way of example only, with reference to the
accompanying drawings in which:
[0054] FIG. 1 shows a front exploded view of a helmet according to
an embodiment of the present invention;
[0055] FIG. 2 shows a rear exploded view of the helmet shown in
FIG. 1;
[0056] FIG. 3 shows a front view of the helmet shown in FIGS. 1 and
2;
[0057] FIG. 4 shows a cross-section view of the helmet shown in
FIGS. 1, 2 and 3;
[0058] FIG. 5 shows a front view of the helmet shown in FIGS. 1 to
4 during an oblique impact;
[0059] FIGS. 6A, 6B and 6C show a selection of views of a plug for
use in the helmet; and
[0060] FIG. 7 shows a cross-section view of a portion of a helmet
according to another embodiment of the present invention.
DETAILED DESCRIPTION
[0061] A helmet acts to protect a user's head from injury by
absorbing energy from an impact. Oblique impacts, which are a
common type of impact, may subject a helmet to significant
tangential forces. Such forces have the potential to cause
rotational acceleration of the user's brain, which may cause
serious brain injuries. Embodiments of the present invention aim to
provide an improved helmet that seeks to mitigate the effect of
such oblique impacts.
[0062] FIGS. 1 to 5 show different views of a helmet 100 according
to an embodiment of the present invention. Both FIGS. 1 and 2 show
an exploded view of the helmet to demonstrate the different
components of the helmet 100 clearly. FIG. 1 shows a view directed
towards the front of the helmet 100. FIG. 2 shows a view directed
towards the back of the helmet 100. The helmet 100 has the
following principal components: an impact absorbing layer 102, an
outer shell 104 and a plug 106.
[0063] The impact absorbing layer 102 is predominately formed of an
out-of-plane honeycomb structure. The impact absorbing layer 102
further comprises a rim 108 around the base of the helmet 100. The
rim 108 is formed from a solid (e.g. non-hollow) material such as
expanded polystyrenes in contrast to the out-of-plane honeycomb
structure 102 which formed of hollow cells, the tessellating cells
having a hexagonal cross section.
[0064] The rim 108 of the impact absorbing layer 102 further
includes a set of grooves 116, into which ridges 118 on the lower
edge of the outer shell 104 (as can be seen in FIG. 2) fit. These
interlocking grooves 116 and ridges 118 help to retain the outer
shell 104 in position on the impact absorbing layer 102 during
normal use. FIG. 2 also shows an additional protrusion 124 on the
impact absorbing layer 102 mounted on the rear of the helmet. The
protrusion 124 interconnects with a corresponding recess 126 on the
outer shell 104, and further helps to retain the outer shell 104 in
position on the impact absorbing layer 102 during normal use.
[0065] As can be seen from FIG. 1, a socket 114 is attached to the
outer surface of the impact absorbing layer 102 into which the plug
106 fits. The plug 106 and the socket 114 fit together via a push
(e.g. friction) fit. Together, the plug 106 and the socket 114 form
a connector that connects the impact absorbing layer 102 and outer
shell 104 together to retain the outer shell 104 on the impact
absorbing layer 102 during normal use.
[0066] The outer shell 104 includes an aperture 110 at the front of
the helmet through which the plug 106 can be inserted when the
outer shell 104 is positioned on the impact absorbing layer 102. To
fit together the plug 106, the outer shell 104 and the impact
absorbing layer 102, the outer shell 104 is first positioned on the
impact absorbing layer 102. This involves interlocking the side
grooves 116 and corresponding complementary ridges 118, as well as
the rear protrusion 124 and the interconnecting recess 126.
[0067] When the outer shell 104 is correctly positioned on the
impact absorbing layer 102, the aperture 110 in the outer shell 104
is aligned with the socket 114. The plug 106 can then be inserted
through the aperture 110 and into the socket 114. A front view of
the helmet 100, with the plug 106 inserted and holding the outer
shell 104 in position, is shown in FIG. 3. FIG. 4, which shows a
cross section view of the helmet 100 in a plane along the central
axis of symmetry of the helmet 100, shows the plug 106 in position
extending through the outer shell 104 and into the socket 114 on
the impact absorbing layer 102.
[0068] FIG. 3 also shows recesses 122 in either side of the inner
surface of the outer shell 104. In FIG. 5, the corresponding
protrusions 120 on the outer surface of the impact absorbing layer
102 are seen, as well as the recesses 122 in the outer shell 104.
When the outer shell 104 is positioned correctly on the impact
absorbing layer 102, the protrusions 120 fit into the recesses 122,
acting to help locate and retain the outer shell 104 on the impact
absorbing layer 102.
[0069] FIG. 5 demonstrates the reaction of the helmet 100 shown in
FIGS. 1 to 4 in an oblique impact. In FIG. 5 the helmet 100, which
is attached to the head of a user who is falling downwards, has
been subject to a collision with the obstacle 502. The edge of the
obstacle 502 which the helmet 100 contacts during the collision is
slanted, and contacts the helmet 100 at a position which is offset
from the centre of the helmet 100, which results in the force
exerted on the helmet from the impact having a significant
tangential component.
[0070] In the impact shown in FIG. 5, the force exerted upon the
helmet 100 during the impact is larger than the particular force
which is required to detach the plug 106 from the socket 114, so to
allow the outer shell to separate from the impact absorbing layer
102. Therefore, upon impact with the obstacle 502, the plug 106 is
ejected from the helmet 100; specifically ejected from the socket
114 on the impact absorbing layer 102. As seen in FIG. 5, the plug
106 completely separates from the helmet 100. However, there may be
other embodiments not shown in which the plug 106 remains in
contact with at least part of the helmet 100 whilst still allowing
the outer shell 104 to separate from the impact absorbing layer
102.
[0071] Upon impact with the obstacle 502, the interconnecting
recesses 122 and protrusions 120, the interconnecting grooves 116
and ridges 118, and the interconnecting protrusion 124 and recess
126 also become disconnected from each other. There are therefore
no remaining features which connect the outer shell 104 to the
impact absorbing layer 102. The outer shell 104 is then able to
rotate on the impact absorbing layer 102. This rotation is caused
by the tangential component of the force exerted on the helmet 100
upon impact with the obstacle 502. The outer shell 104 rotating
independently of the impact absorbing layer 102 (and ultimately the
head of the user) reduces the rotation of head of the user, which
may reduce the injuries sustained from the impact.
[0072] The Applicant has found that helmets according to
embodiments of the present invention may reduce the rotational
acceleration and velocity experienced the head of a user, compared
to conventional foam helmets, by approximately 25% (in rotational
acceleration) and approximately 45% (in rotational velocity).
[0073] FIGS. 6A, 6B and 6C show various views of the plug 106. As
can be seen in these Figures, the plug 106 comprises an outer head
602. The outer head 602 has an area greater than that of the
aperture 110 into which the plug fits. After insertion of the plug
106 through the aperture 110 and into socket 114, the outer head
602 sits outside of the outer shell 104 as seen in FIG. 3.
[0074] The plug 106 further comprises a neck 604, which is
connected to the outer head 602. In examples in which the plug 106
and the socket 114 fit together via a push (e.g. friction) fit, the
neck 602 may be made from a deformable plastic such that the neck
602 of the plug 106 can be inserted into the socket 114. The neck
604 has ridges 606 which act to hold the plug 106 in position in
the socket 114. The socket may comprises corresponding grooves
which mate with the ridges 606 of the plug 106 when the plug 106 is
inserted into the socket.
[0075] FIG. 7 shows a cross-sectional view of a portion of a helmet
700 according to another embodiment of the present invention. The
helmet 700 has the following principal components: an impact
absorbing layer 702, an outer shell 704 and a latch 706. The latch
706 may be positioned in a similar location as the plug shown in
previous figures.
[0076] The latch 706 is integral to (e.g. formed from the same
material as) the impact absorbing layer 702. The latch 706 includes
a flexible portion 708 that attaches the latch 706 to the main body
of the impact absorbing layer 702. The flexible portion acts as a
living hinge to allow the position of the latch 706 to change
relative to the main body of the impact absorbing layer 702 and the
outer shell 704. The latch 706 also includes a block tip 707.
[0077] The impact absorbing layer 702 additionally includes a
cavity 714. When a force is applied to the latch 706, the flexible
portion 708 bends, which may move the latch 706 into the cavity
714.
[0078] The outer shell 704 includes an aperture 705. During normal
use (e.g. not during an accident), the latch 706 extends through
the aperture 705. The block tip 707 of the latch 706 helps to keep
the outer shell 704 in position on the impact absorbing layer 702
during normal use, by interacting with the edges of the aperture
705 to prevent translational movement of the outer shell 704 with
respect to the impact absorbing layer 702.
[0079] Upon impact with an obstacle (e.g. similar to that seen in
FIG. 5), the force of the impact acts on the flexible portion 708
of the latch 706, causing the flexible portion 708 to bend. The
direction in which the flexible portion 708 is bent may depend on
the direction of the tangential forces acting on the helmet upon
impact.
[0080] In an impact in which the tangential forces act in the
direction shown by arrow 730, i.e. the impact force acts downwards,
as the outer shell 704 rotates downwards it moves over the latch
706 and the latch 706 is pushed into the cavity 714. This allows
the outer shell 704 to detach from and move over the impact
absorbing layer 702, helping to reduce the tangential forces
transferred to the head of the user.
[0081] In an impact in which the tangential forces act in the
direction shown by arrow 740, i.e. the impact force acts upwards,
as the outer shell 704 rotates, the edge of aperture 705 of the
outer shell 704 engages against the block tip 707 of the latch 706.
The force exerted on the latch 706 either moves the latch 706 into
the cavity 714, or rotates the latch 706 away from the cavity 714
and back on itself. Either of these movements of the latch 706
allows the outer shell 704 to detach from and/or move obstruction
free over the impact absorbing layer 702, helping to reduce the
tangential forces transferred to the head of the user.
[0082] In an impact in which the tangential forces act in another
direction to that shown by arrows 730, 740, both of the
abovementioned mechanisms may occur (e.g. at least in part) in
order to enable the separation of the outer shell 704 and the
impact absorbing layer 702.
[0083] In general, the latch 706 shown in FIG. 7, is able to
maintain its functionality after an impact. For example, in an
impact in which the latch 706 is merely compressing into the cavity
714 such that the outer shell 704 can move freely on the impact
absorbing structure 702, after the impact the original (or a new)
outer shell 704 may be repositioned on the impact absorbing
structure 702.
[0084] The latch 706 may also be manually compressed into the
cavity 714 by a user, e.g. to allow for easy intentional removal
the outer shell 704. This may allow the outer shell 704 to be
interchangeable, for example for aesthetic purposes.
[0085] Thus it will be appreciated by those skilled in the art that
a helmet according to embodiments of the present invention, in
which two independent layers (the outer shell and impact absorbing
layer) connected by a connector, which allows the layers to
separate when the helmet is subject to an impact, helps to reduce
the tangential forces that may be transferred from an oblique
impact to the head of the user. This may provide significant
benefits over known helmets, e.g. in helping to reduce brain
injuries. It will further be appreciated however that many
variations of the specific arrangements described herein are
possible within the scope of the invention. For example, a
different type of connector (as opposed to a plug and socket and
arrangement) may be provided to connect the outer shell to the
impact absorbing layer.
* * * * *