CA3221588A1

CA3221588A1 - Helmet

Info

Publication number: CA3221588A1
Application number: CA3221588A
Authority: CA
Inventors: Amy Louise POMERING
Original assignee: Mips AB
Current assignee: Mips AB
Priority date: 2021-06-25
Filing date: 2022-06-16
Publication date: 2022-12-29
Also published as: EP4358781A1; US20240245161A1; TW202302003A; CN117460437A; GB202109168D0; WO2022268647A1

Abstract

A helmet (1) comprising: an outer shell (2); 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 (21) is provided between the head mount and the outer shell; the head mount comprises a plurality of straps (20), that are configured to extend across the top of the head of a wearer of the helmet, and a head ring (30) 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 (40) 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 (80) 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.

Description

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.

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.

2 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.

3 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.

4 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;

5 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

6

7 PCT/EP2022/066500 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, 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

8 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

9 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 be 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 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.

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 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 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 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 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.

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 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.

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 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 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 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 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 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 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 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 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.

Claims

1. 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.

2. A helmet according to claim 1, wherein 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.

3. A helmet according to claim 2, wherein 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.

4. A helmet according to claim 2 or 3, wherein 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.

5. A helmet according to any one of claims 2 to 4, wherein 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.

6. A helmet according to any one of claims 2 to 5, wherein 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

7. A helmet according to any one of claims 2 to 6, wherein 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

8. A helmet according to any one of claims 2 to 7, comprising 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.

9. A helmet according to claim 8, wherein at least one connector is provided on the crown section of the head engagement device support.

10. A helmet according to claim 8 or claim 9, wherein at least one connector is provided on a limb section of the head engagement device support.

11. A helmet according to claim 10, wherein 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.

12. A helmet according to any one of claims 8 to 11, wherein 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.

13. A helmet according to any one of the preceding claims, wherein the head engagement device support comprises at least one outer surface formed from a fabric or felt.

14. A helmet according to claim 13, wherein the head engagement device support is formed from a material comprising a layer of foam laminated between two layers of fabric or felt; and wherein the foam layer is stiffer than the layers of fabric or felt.

15. A helmet according to claim 13, wherein 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.

16. A helmet according to any one of the preceding claims, wherein 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.

17. A helmet according to claim 16, wherein 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.

18. A helmet according to any one of the preceding claims, wherein the head engagement device is connected to the head mount.

19. A helmet according to any one of the preceding claims, wherein the head mount comprises a plurality of straps that extend between an opposing pair of connection points on the outer shell.

20. A helmet according to any one of the preceding claims, wherein the head engagement device is provided as a single component.

21. A helmet according to any one of claims 1 to 19, wherein the head engagement device is formed from plural separate sections.

22. A helmet according to any one of the preceding claims, wherein 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.

23. A helmet according to claim 22, wherein the head engagement device further comprises an intermediate region that connects the crown region to the frontal region.

24. A helmet according to any one of the preceding claims, wherein the head engagement device comprises a plate of material, optionally shaped to conform to the head of a wearer of the helmet.

25. A helmet according to any one of the preceding claims, wherein, 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.