JP7565610B2 - helmet - Google Patents

Description

The present invention relates to a helmet, and more particularly to a helmet having a removable outer shell.

Head injuries can be sustained as a result of participating in sports (such as cycling, horse riding, or rock climbing), and head injuries are a common cause of serious brain injuries. Impact protection is therefore important in preventing brain injuries as a result of impact to the head. Head protection (in the form of a helmet) is designed to reduce the forces experienced by a user's head during an impact. Typically, a helmet includes at least one impact absorbing layer that is designed to absorb a portion of the forces experienced by the helmet during an impact.

However, helmets often do not provide adequate protection during oblique impacts, which expose the helmet to large tangential forces. Oblique impacts are common because the impact rarely occurs directly along a direction normal to the helmet's outer surface without an additional component in other directions. Tangential forces result in rotational acceleration of the brain, which has been associated with bridging vein rupture, and which can cause subdural hematomas and diffuse axonal injury.

The object of the present invention is to provide an improved helmet.

Viewed from a first aspect, the present invention provides a helmet comprising:
A shock absorbing layer;
an outer shell mounted over an outer surface of the impact absorbing layer;
a connector connecting the outer shell to the shock absorbing layer to maintain the outer shell on the shock absorbing layer;
The connectors are positioned to allow the outer shell to separate from the impact absorbing layer when the helmet is subjected to an impact.

The present invention relates to a helmet including an impact absorbing layer and an outer shell, the impact absorbing layer and the outer shell being connected together by a connector, e.g., to keep the outer shell over the impact absorbing layer during normal use. When the helmet is subjected to an impact (and thus an external force acts on the helmet), the connector is arranged to allow the outer shell to separate from the impact absorbing layer (i.e., to be moved from a position where the outer shell is mounted over the impact absorbing layer and the connector connects them to a different position). For example, the outer shell may be configured such that when it is not connected to the impact absorbing layer by the connector, it can rotate about the impact absorbing layer.

Those skilled in the art will recognize that due to the manner in which the outer shell is removably connected to the shock absorbing layer via the connector, when the outer shell is separated from the shock absorbing layer (due to it no longer being held in place by the connector), the outer shell can move (and, for example, rotate) around the outer surface of the shock absorbing layer. Thus, when the helmet is subjected to an impact that includes at least a tangential component (i.e., that is not only along a direction normal to the helmet's outer surface), at least a portion of the tangential force created by the impact can act to rotate the outer shell. This helps reduce the rotation of the user's head and therefore reduces the transmission of tangential forces from the impact. This is because the user's head (e.g., with the shock absorbing layer still attached to it) can translate (e.g., slide or rotate) within the outer shell instead of being subjected to the tangential force itself.

When the tangential forces experienced by the head are reduced (thus reducing the rotational acceleration experienced by the head), the risk of injury such as bridging vein rupture is reduced. Reducing the tangential forces experienced by the user's head further reduces the risk of neck injury caused by excessive rotation of the head relative to the neck.

In at least the preferred embodiment, the shock absorbing layer is designed to provide a degree of protection to the user's head against the bulk forces exerted upon the helmet during an impact. Thus, preferably, the shock absorbing layer is positioned to absorb at least a portion of the normal component of the forces exerted upon the helmet during an impact.

The shock absorbing layer may be formed from any suitable and desired material (e.g., expanded polystyrene, etc.). In a preferred set of embodiments, the shock absorbing layer includes a hollow cell structure, e.g., a plurality of hexagonal (cross-sectional) cells. Preferably, at least a plurality of the cells tessellate with each other. For example, the shock absorbing layer structure may include a micro-truss lattice or an out-of-plane honeycomb. The shock absorbing layer may further include a rim portion, e.g., around the (lower) edge of the hollow cell structure.

Typically, in conventional helmets that include an outer shell, the outer shell may be provided primarily as an aesthetic feature used to improve the appearance of the helmet. Such outer shells are typically not connected as separate, distinct parts of the helmet (hence, in contrast to the outer shell of the present invention). Instead, conventional helmets may be manufactured in a mold, and the material forming the impact absorbing layer is injected into the mold. In the present invention, the applicant has recognized that the outer shell may also help reduce the rotation of the user's head when the helmet is subjected to an impact. Preferably, the outer shell is formed from a rigid material, such as a thermoplastic (e.g., polycarbonate) or carbon fiber, or a composite material. However, it may be made from any suitable and desired material. Preferred materials for forming the outer shell have a high strength to weight ratio.

In a preferred set of embodiments, the outer shell has a thickness that is significantly smaller than the thickness of the shock absorbing layer. The outer shell can therefore include a membrane, for example a membrane that at least partially covers the shock absorbing layer. The outer shell is therefore designed to break away from the shock absorbing layer when exposed to an impact, but the outer shell itself may 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, for example a thickness of less than 4 mm, for example a thickness of less than 2 mm, for example a thickness of less than 0.5 mm. Different outer shell thicknesses may be advantageous for different types of helmets, for example a motorcyclist helmet may preferably have a thicker outer shell (e.g., 6 mm), while a bicycle helmet may have a thinner outer shell (e.g., less than 4 mm).

Preferably, the shock absorbing layer has a thickness (e.g., normal) between 10 mm and 50 mm, for example between 20 mm and 30 mm. Different shock absorbing layer thicknesses may be suitable for different types of helmets, for example, motorcyclist helmets may preferably have a thicker shock absorbing layer (e.g., between 20 mm and 50 mm), while bicycle helmets may have a thinner shock absorbing layer (e.g., between 10 mm and 30 mm).

In a preferred set of embodiments, the outer shell covers at least 60%, such as at least 70%, such as at least 80% of the surface area of the outer surface of the impact absorbing layer. The outer shell preferably covers the impact absorbing layer at one or more (e.g., all) locations on the helmet that may experience an impact. The outer shell may include one or more vent apertures to allow air to flow. The outer shell (when provided) may not extend over the rim portion of the impact absorbing layer. Thus, for example, the outer shell may extend only over the outer surface of the hollow cell structure. However, in other examples, the shell extends at least partially over the rim portion.

In one set of embodiments, the outer shell has a smooth outer surface, for example, within which the shock absorbing layer is formed from a plurality of cells. In one set of embodiments, the inner surface of the outer shell is smooth. Such an embodiment may be advantageous because providing a smooth surface allows the outer shell to roll over the shock absorbing layer with minimized resistance upon impact.

The connectors are designed to keep the outer shell on the shock absorbing layer (e.g., during normal use) and to allow the outer shell to separate from the shock absorbing layer during an impact. This can allow the outer shell to move (e.g., rotate) around the outer surface of the shock absorbing layer. This can be achieved in any suitable or desired manner. For example, the connectors can be arranged to keep the outer shell in place on the shock absorbing layer when weaker forces act on the helmet (e.g., as would be expected in normal use) and to allow the outer shell to separate from the outer shell when stronger forces act on the helmet (e.g., as a result of an impact). Preferably, the connectors extend radially (e.g., perpendicularly) to the surface of the shock absorbing layer (e.g., parallel to the walls of the cells) and/or perpendicularly to the surface of the outer shell.

In one set of embodiments, the connectors are arranged to allow the outer shell to separate from the shock absorbing layer when the helmet (e.g., the outer shell of the helmet) is subjected to an impact having a specific (e.g., predetermined) force (e.g., oblique force). This helps to keep the outer shell on the shock absorbing layer during normal use and separate from the shock absorbing layer when subjected to an impact. The specific force required for the connectors to allow the outer shell to separate from the shock absorbing layer can be chosen to have any suitable and desired value (e.g., such that the outer shell separates from the shock absorbing layer only as a result of a sufficiently large impact). In one embodiment, the specific (e.g., predetermined) force is between 10N and 100N, e.g., between 30N and 70N, e.g., approximately 50N. The specific force can be chosen, for example, to reflect the lowest range of forces acting on the helmet that may cause damage.

The connector may be positioned at any suitable and desired location on the helmet. Preferably, however, the connector is positioned along an axis of symmetry of the helmet, e.g., along a central plane of the helmet extending rearward from the front of the helmet. In one set of embodiments, the connector is positioned at the front of the helmet. Locating the connector at the front of the helmet can be particularly useful in aiding in removal of the outer shell in oblique impacts, especially for impacts offset from the central axis of symmetry (and thus the front of the helmet).

The connector can have any suitable and desired form, for example, such that when the helmet is subjected to an impact (e.g., having a force greater than a certain value (e.g., approximately 50 N)), it is arranged to allow the outer shell to separate from the impact absorbing layer. In one set of embodiments, the connector comprises a separate component from the outer shell and the impact absorbing layer. Thus, preferably at least a portion (e.g., separate component) of the connector is arranged to detach from the impact absorbing layer and/or the outer shell when the helmet is subjected to an impact, for example such that at least a portion (e.g., separate component) of the connector is no longer in contact with the remainder of the helmet, thus allowing the outer shell to separate from the impact absorbing layer.

In one set of embodiments, the connector includes a plug, the plug extending between the outer shell and the shock absorbing layer (e.g., attached to both the outer shell and the shock absorbing layer). Preferably, the outer shell includes an aperture for receiving the plug. Thus, for example, the plug extends through the aperture and is attached to the shock absorbing layer (e.g., a socket in the shock absorbing layer). Thus, the plug may be accessible from outside the outer shell. This allows the plug to be easily removed, and it is possible to interchange the plug and/or the outer shell. Interchanging the plug or the outer shell is particularly advantageous if either is accidentally damaged or for aesthetic reasons.

Preferably, the plug includes an outer head having a dimension larger than the corresponding dimension of the aperture. Thus, the outer head of the plug can cover (e.g., encase) a portion of the outside of the outer shell. This further aids in easier removal of the plug and allows the plug and/or the outer shell to be interchangeable.

The plug may be attached to the shock absorbing layer in any suitable and desired manner. The plug may be attached directly to the shock absorbing layer. For example, in an embodiment in which the shock absorbing layer includes a hollow cell structure (e.g., including a plurality of cells), the plug may be attached directly into a cell of the hollow cell structure of the shock absorbing layer.

In a preferred set of embodiments, the connector includes a socket (e.g., a clip) for receiving a plug of the connector. Preferably, the socket is formed on or attached to an outer surface of the impact absorbing layer. Thus, when the outer shell is held mounted on the impact absorbing layer, the plug is positioned in the socket. Preferably, when the helmet is subjected to an impact, the plug is arranged to be removed from the socket, which allows the outer shell to separate from the impact absorbing layer.

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 can include complementary (e.g., male and female) parts that (e.g., fit together) to form the connector. Thus, for example, the outer shell can include a female (or male) member and the impact absorbing layer can include a corresponding male (or female) member that connect together and attach the outer shell to the impact absorbing layer. As outlined above, for example, the male member can include a plug and the female member can include a complementary socket.

In one set of embodiments, the connector includes a (e.g. hinged) protrusion (e.g. a protruding latch). Preferably, the protrusion is integral with (includes a portion of) the shock absorbing layer. Preferably, the protrusion is attached to (e.g. integral with) the main body of the shock absorbing layer by a flexible (e.g. hinged) portion. Preferably, the flexible portion is formed from (e.g. integral with) the same material as the shock absorbing layer.

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., the material of the shock absorbing layer and/or the protrusion). The flexible portion allows the protrusion to bend and/or deform (e.g., relative to the shock absorbing layer) when a force is applied, for example, without fracturing and/or rupturing the protrusion or its attachment to the main body portion of the shock absorbing layer (via the flexible portion).

In one set of embodiments, the impact absorbing layer includes a cavity, the cavity being arranged to receive the protrusion, for example, when the protrusion bends or deforms (e.g., via the flexible portion) relative to a main body portion of the impact absorbing layer. This may occur, for example, when a force is applied to the protrusion (e.g., via the outer shell). Preferably, the protrusion is arranged to bend and/or deform relative to a main body portion of the impact absorbing layer, allowing the outer shell to separate from the impact absorbing layer when the helmet is subjected to an impact. Thus, preferably, during normal use of the helmet, the cavity is empty and the protrusion does not substantially protrude into the cavity.

Preferably, the outer shell includes an aperture for receiving the protrusion (e.g., in the manner of a latch). The protrusion and aperture are preferably arranged such that, for example, the protrusion extends through the aperture when no force is applied to the protrusion. Preferably, the protrusion and aperture are arranged to keep the outer shell over the shock absorbing layer.

Preferably, the protrusion and aperture are arranged such that when a force is applied to the protrusion (e.g., as a result of a force being applied to the outer shell), the protrusion and aperture move relative to one another (e.g., away from one another), allowing the outer shell to move relative to the shock absorbing layer. This may be because the protrusion is forced into the cavity, or because the outer shell is bent away from the protrusion. Preferably, this results in the protrusion no longer extending through the aperture in the outer shell.

This arrangement can help maintain the outer shell in a desired position on the impact absorbing structure during normal use while allowing movement (e.g., translation) of the outer shell on the impact absorbing layer when the protrusion is displaced into a cavity in the impact absorbing layer (e.g., due to a force being applied to the protrusion during an accident or by intentional means by a user, such as removing the outer shell from the impact absorbing layer).

In any of the embodiments described herein, the components of the connector may be attached to one another (and/or to the outer shell and/or shock absorbing layer) in any suitable or desired manner, for example, to provide them with an attachment that requires a particular separation force (e.g., a particular force required to separate the outer shell from the shock absorbing layer as outlined above).

For example, the plug and the shock absorbing layer (e.g., the shock absorbing layer's socket) may be attached 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 include one or more grips, ridges, or latches. The grips, ridges, or latches can help control (e.g., increase) the friction therebetween, and thus help control (e.g., increase) the force that needs to be exerted on the connector to allow the outer shell to separate from the shock absorbing layer when the helmet is subjected to an impact.

The connector may be formed from any suitable and desired material. Preferably, the connector (e.g., plug and/or socket) is formed from a rigid material such as a 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), or the like. The connector (e.g., plug and/or socket) may be formed from multiple parts that may be fabricated from different materials, as desired. For example, as outlined above, at least a portion of the connector may be integrally formed with the shock absorbing layer (and thus preferably formed from the same material as the shock absorbing layer).

In some embodiments, the connector is positioned so that the helmet separates or breaks into separate parts upon impact, rather than deforming and absorbing energy upon impact. Preferably, the plug is weaker than the outer shell, allowing the connector to break away before the shell fractures during impact.

The connectors may be arranged in any suitable and desired manner to allow the outer shell to separate from the shock absorbing layer as a result of an impact. Moreover, the outer shell and the shock absorbing layer may be arranged to separate from each other in any suitable and desired manner. In a preferred embodiment, the outer shell is arranged to be displaced relative to the shock absorbing layer (e.g., rotated about the shock absorbing layer) when, for example, the helmet is subjected to an oblique impact (such that tangential and radial forces are exerted on the helmet). Preferably, the displacement of the outer shell causes the connectors to separate (e.g., the plug is removed), for example due to shear forces.

The outer shell may be displaced relative to the shock absorbing layer in any suitable and desired manner. Preferably, the outer shell is arranged to translate (e.g., slide or rotate) relative to the shock absorbing layer when the helmet is subjected to an impact. Thus, preferably, apart from the connector (and any further features (e.g., as outlined herein) that help, for example, to position the outer shell relative to the shock absorbing layer), the outer shell is not fixed (e.g., not permanently glued, taped or attached by the connector) to the shock absorbing layer. This allows the outer shell to be separated from the shock absorbing layer when the connector no longer connects the outer shell to the shock absorbing layer. Thus, preferably, the portion that is integral (e.g., away from the periphery of the outer shell) with the outer shell (e.g., the inner surface of the outer shell) is not attached to the shock absorbing layer.

When exposed to an impact that causes the outer shell to separate from the shock absorbing layer, preferably the connector is arranged to allow the outer shell to separate from the shock absorbing layer within 5 ms of the impact. Preferably, the outer shell and the shock absorbing layer are arranged to move (e.g., rotate) relative to one another in a time between 10 ms and 15 ms when exposed to an impact (e.g., after the outer shell separates from the shock absorbing layer).

While it is possible for the helmet to include only one connector, in one set of embodiments the helmet includes multiple connectors connecting the outer shell to the impact absorbing layer. The multiple connectors may be the same or different. Preferably, the multiple connectors are 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 multiple connectors are positioned at respective different locations on the helmet. For example, the connectors may be positioned at particular angles around the base of the outer shell and may be evenly spaced from each other, for example.

The connector preferably provides the primary connection connecting the outer shell to the impact absorbing layer and keeping the outer shell on the impact absorbing layer, but the helmet can include one or more additional features that aid in (correct) positioning and retention of the outer shell on the impact absorbing layer. The impact absorbing layer (e.g., a rim portion of the impact absorbing layer) can include at least one groove or protrusion formed therein. In some embodiments, the outer shell can include at least one inwardly protruding ridge (e.g., a clip).

Preferably, the at least one ridge corresponds (e.g., in terms of location and dimensions) to (e.g., at a suitable location) and engages with at least one groove (or protrusion) in the shock absorbing layer (e.g., a rim portion of the shock absorbing layer) such that the ridge is positioned in the groove (or over the protrusion) when the outer shell is mounted over the shock absorbing layer. Thus, the at least one ridge can be positioned in the at least one groove (when the outer shell is mounted over the shock absorbing layer) such that there is an additional attachment point between the outer shell and the shock absorbing layer, not just a connector. The interconnecting ridges and grooves (or protrusions) help to keep the outer shell in the proper position during typical use.

Preferably, the interconnecting ridges and grooves (or protrusions) provide a weaker connection between the outer shell and the shock absorbing layer than that provided by the connector. During an impact, when the connector separates the outer shell from the shock absorbing layer, at least one ridge is forced out of position from its corresponding groove (or protrusion), allowing the outer shell to separate from the shock absorbing layer.

Thus, in one embodiment, the ridges and grooves (or protrusions) are arranged such that a specific (e.g., predetermined) force is required to remove the ridges from the corresponding complementary grooves (or protrusions) (e.g., interconnected when the outer shell is mounted on the shock absorbing layer). Preferably, this specific (e.g., predetermined) force is less than the specific (e.g., predetermined) force required for the connector to allow the outer shell to separate from the shock absorbing layer when the helmet is subjected to an impact. This helps ensure that the force of the impact will be sufficient to disconnect the connector between the outer shell and the shock absorbing layer, and that upon disconnection of the outer shell from the shock absorbing layer, the ridges and grooves (or protrusions) will preferably disengage (or have already disengaged) from each other and will preferably not act to provide additional resistance in keeping the outer shell on the shock absorbing layer.

In some embodiments, the shock absorbing layer (e.g., a rim portion of the shock absorbing layer) includes at least one ridge and the outer shell includes at least one groove (or protrusion), i.e., the positioning of the ridge and groove on the shock absorbing layer and outer shell is inverted compared to the arrangement described above. The features of the ridge and groove (or protrusion) outlined herein are equally applicable to this embodiment.

The one or more grooves (or protrusions) and ridges may be positioned at any suitable and desired location around the shock absorbing layer and the outer shell (e.g., at its rim). In one set of embodiments, the grooves (or protrusions) are equally spaced around the shock absorbing layer (e.g., at the rim of the shock absorbing layer). The one or more ridges are preferably correspondingly positioned toward (e.g., at) the bottom edge (e.g., at the rim) of the outer shell. For example, complementary grooves (or protrusions) and ridges may be positioned on the sides and rear of the helmet. Providing multiple interconnecting grooves (or protrusions) and ridges allows the shell to be more securely held in place over the shock absorbing layer when the outer shell is fitted over the shock absorbing layer during normal use.

In one embodiment, for example, in addition to the ridges and grooves (or protrusions) outlined above, the shock absorbing layer can include at least one protrusion on its outer surface to help keep the outer shell in place on the shock absorbing layer during normal use. When the shock absorbing layer includes multiple protrusions, the protrusions are preferably evenly spaced around the outer surface of the shock absorbing layer. In this embodiment, the outer shell preferably includes at least one recess that corresponds to (and is complementary to) the at least one protrusion of the shock absorbing layer. Thus, when the outer shell is positioned over the outer surface of the shock absorbing layer, at least one protrusion on the shock absorbing layer interconnects with at least one corresponding recess.

Preferably, the complementary protrusions and recesses are provided (only) to assist in positioning the outer shell in its correct position on the shock absorbing layer. Thus, preferably, the complementary protrusions and recesses provide a (e.g., significantly) weaker connection between the outer shell and the shock absorbing layer than that provided by the connector (and, e.g., by the complementary grooves (or protrusions) and ridges). During an impact, when the connector disconnects the outer shell from the shock absorbing layer, the protrusions and recesses move away from each other, allowing the outer shell to separate from the shock absorbing layer.

Thus, in one embodiment, the complementary protrusions and recesses are arranged such that a specific (e.g., predetermined) force is required to displace the protrusion from the complementary recess. Preferably, this specific (e.g., predetermined) force is (e.g., significantly) less than the specific (e.g., predetermined) force required for the connector to allow the outer shell to separate from the impact absorbing layer when the helmet is subjected to an impact. This helps ensure that the force of the impact will be sufficient to decouple the connector between the outer shell and the impact absorbing layer, and that upon decoupling of the outer shell from the impact absorbing layer, the complementary protrusions and recesses will also preferably be (or have already been) displaced from each other and will preferably not act to provide additional resistance in keeping the outer shell on the impact absorbing layer.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a front exploded view of a helmet according to an embodiment of the present invention. FIG. 2 is a rear exploded view of the helmet shown in FIG. 1. FIG. 3 is a front view of the helmet shown in FIGS. 1 and 2 . FIG. 4 is a cross-sectional view of the helmet shown in FIGS. 1, 2 and 3. FIG. 5 is a front view of the helmet shown in FIGS. 1 to 4 during an oblique impact. 1A-1D are various views of a plug for use in a helmet. 1A-1D are various views of a plug for use in a helmet. 1A-1D are various views of a plug for use in a helmet. 11 is a cross-sectional view of a portion of a helmet according to another embodiment of the present invention.

Helmets act to protect a user's head from injury by absorbing energy from an impact. Oblique impacts, which are a common type of impact, can expose the helmet to large tangential forces. Such forces have the potential to cause rotational acceleration of the user's brain, which can result in serious brain injuries. Embodiments of the present invention aim to provide an improved helmet that seeks to mitigate the effects of such oblique impacts.

Figures 1 to 5 show different views of a helmet 100 according to an embodiment of the present invention. Both Figures 1 and 2 show exploded views of the helmet to clearly show the different components of the helmet 100. Figure 1 shows a view oriented towards the front of the helmet 100. Figure 2 shows a view oriented towards the back of the helmet 100. The helmet 100 has the following main components: a shock absorbing layer 102, an outer shell 104, and a plug 106.

The shock absorbing layer 102 is formed primarily from an out-of-plane honeycomb structure. The shock absorbing layer 102 further includes a rim portion 108 around the base of the helmet 100. The rim portion 108 is formed from a solid (e.g., non-hollow) material such as expanded polystyrene, in contrast to the out-of-plane honeycomb structure 102, which is formed from hollow cells, and the tessellating cells have a hexagonal cross-section.

The rim portion 108 of the shock absorbing layer 102 further includes a set of grooves 116 into which ridges 118 on the lower edge of the outer shell 104 fit (as can be seen in FIG. 2). These interlocking grooves 116 and ridges 118 help to keep the outer shell 104 in the proper position on the shock absorbing layer 102 during normal use. FIG. 2 also shows an additional protrusion 124 on the shock absorbing layer 102 that is attached to the rear of the helmet. The protrusion 124 interconnects with a corresponding recess 126 on the outer shell 104, further helping to keep the outer shell 104 in the proper position on the shock absorbing layer 102 during normal use.

As can be seen from FIG. 1, the socket 114 is attached to the outer surface of the shock absorbing layer 102 and the plug 106 fits into it. The plug 106 and socket 114 fit together via a push (e.g., friction) fit. Together, the plug 106 and socket 114 form a connector that connects the shock absorbing layer 102 and the outer shell 104 together and keeps the outer shell 104 over the shock absorbing layer 102 during normal use.

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 over the shock absorbing layer 102. To fit the plug 106, outer shell 104, and shock absorbing layer 102 together, the outer shell 104 is first positioned over the shock absorbing layer 102. This requires interlocking of the side grooves 116 and corresponding complementary ridges 118, as well as interlocking of the rear projections 124 and interconnecting recesses 126.

When the outer shell 104 is properly positioned on the shock 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 place is shown in FIG. 3. FIG. 4 shows a cross-sectional view of the helmet 100 in a plane along the central axis of symmetry of the helmet 100, showing the plug 106 in the proper position, extending through the outer shell 104 into the socket 114 on the shock absorbing layer 102.

3 also shows recesses 122 on either side of the inner surface of the outer shell 104. In FIG. 5, corresponding protrusions 120 on the outer surface of the shock absorbing layer 102 can be seen, as well as recesses 122 in the outer shell 104. When the outer shell 104 is properly positioned on the shock absorbing layer 102, the protrusions 120 fit into the recesses 122 and act to help position and hold the outer shell 104 on the shock absorbing layer 102.

Figure 5 shows the response of the helmet 100 shown in Figures 1 to 4 in an oblique impact. In Figure 5, the helmet 100, which is attached to the head of a user falling downwards, is subjected to impact with an obstacle 502. The edge of the obstacle 502 that the helmet 100 contacts during the impact is angled and contacts the helmet 100 at a location that is offset from the center of the helmet 100, which results in the force exerted on the helmet from the impact having a large tangential component.

In the impact shown in FIG. 5, the force exerted on the helmet 100 during the impact is greater than the specific force required to remove the plug 106 from the socket 114, allowing the outer shell to separate from the impact absorbing layer 102. Thus, upon impact with the obstacle 502, the plug 106 is ejected from the helmet 100, specifically from the socket 114 above the impact absorbing layer 102. As seen in FIG. 5, the plug 106 is completely separated from the helmet 100. However, there can be other embodiments, not shown, in which the plug 106 remains in contact with at least a portion of the helmet 100 while still allowing the outer shell 104 to separate from the impact absorbing layer 102.

Upon impact with the obstacle 502, the interconnecting recesses 122 and protrusions 120, the interconnecting grooves 116 and ridges 118, and the interconnecting protrusions 124 and recesses 126 are also separated from each other. Thus, there are no remaining features connecting the outer shell 104 to the shock absorbing layer 102. The outer shell 104 can then rotate on the shock 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 shock absorbing layer 102 (and ultimately the user's head) reduces the rotation of the user's head, which can reduce damage from the impact.

Applicant has found that helmets according to embodiments of the present invention are capable of reducing the rotational acceleration and rotational velocity experienced by a user's head by approximately 25% (in rotational acceleration) and approximately 45% (in rotational velocity) as compared to conventional foam helmets.

6A, 6B, and 6C show various views of the plug 106. As can be seen in these views, the plug 106 includes an outer head 602. The outer head 602 has an area that is larger than the area of the aperture 110 into which the plug fits. After inserting the plug 106 through the aperture 110 and into the socket 114, the outer head 602 sits on the outside of the outer shell 104, as seen in FIG. 3.

The plug 106 further includes a neck 604 that is connected to the outer head 602. In an example where 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 may be inserted into the socket 114. The neck 604 has a ridge 606 that acts to hold the plug 106 in place in the socket 114. The socket may include a corresponding groove that mates with the ridge 606 of the plug 106 when the plug 106 is inserted into the socket.

Figure 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 major components: an impact absorbing layer 702, an outer shell 704, and a latch 706. The latch 706 may be positioned in a similar location to the plug shown in the previous figure.

The latch 706 is integral with the shock absorbing layer 702 (e.g., formed from the same material as the shock absorbing layer 702). The latch 706 includes a flexible portion 708 that attaches the latch 706 to the main body portion of the shock absorbing layer 702. The flexible portion acts as a living hinge, allowing the position of the latch 706 to change relative to the main body portion of the shock absorbing layer 702 and the outer shell 704. The latch 706 also includes a block tip 707.

The shock absorbing layer 702 additionally includes a cavity 714. When a force is applied to the latch 706, the flexible portion 708 bends, which can move the latch 706 into the cavity 714.

The outer shell 704 includes an aperture 705. During normal use (e.g., not during an accident), a latch 706 extends through the aperture 705. A blocking tip 707 of the latch 706 interacts with an edge of the aperture 705 to help maintain the outer shell 704 in the proper position over the shock absorbing layer 702 during normal use and prevents translational movement of the outer shell 704 relative to the shock absorbing layer 702.

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 bends can depend on the direction of the tangential force acting on the helmet upon impact.

In an impact where a tangential force acts in the direction indicated by arrow 730 (i.e., the impact force acts downwards), as the outer shell 704 rotates downward, it moves over the latch 706, forcing the latch 706 into the cavity 714. This allows the outer shell 704 to disengage from and move over the shock absorbing layer 702, helping to reduce the tangential force transmitted to the user's head.

In an impact where the tangential force acts in the direction indicated by arrow 740 (i.e., the impact force acts upwards), the edge of the aperture 705 of the outer shell 704 engages the blocking tip 707 of the latch 706 as the outer shell 704 rotates. The force exerted on the latch 706 either moves the latch 706 into the cavity 714 or rotates the latch 706 back onto itself, away from the cavity 714. Either of these movements of the latch 706 allows the outer shell 704 to disengage from the shock absorbing layer 702 and/or to allow obstructions to move freely above the shock absorbing layer 702, helping to reduce the tangential force transmitted to the user's head.

In an impact where the tangential force acts in a direction other than that indicated by arrows 730, 740, both of the above-mentioned mechanisms may occur (e.g., at least in part) to allow separation of the outer shell 704 and the shock absorbing layer 702.

Generally, the latch 706 shown in FIG. 7 can maintain its functionality after an impact. For example, in an impact where the latch 706 simply compresses into the cavity 714 so that the outer shell 704 is free to move over the shock absorbing structure 702, the original (or new) outer shell 704 can be repositioned over the shock absorbing structure 702 after the impact.

Also, the latch 706 can be manually compressed into the cavity 714 by a user, allowing for easy intentional removal of the outer shell 704, for example. This can allow the outer shells 704 to be interchangeable, for example, for aesthetic purposes.

Thus, it will be appreciated by those skilled in the art that in helmets according to embodiments of the present invention, two separate layers (the outer shell and the shock absorbing layer) are connected by a connector that allows the layers to separate when the helmet is subjected to an impact, and that helmets according to embodiments of the present invention help reduce tangential forces that may be transmitted to a user's head from an oblique impact. This can provide significant benefits over known helmets, for example, in helping to reduce brain injury. However, it will be further appreciated that many variations of the specific arrangements described herein are possible within the scope of the present invention. For example, different types of connectors (as opposed to plug and socket and arrangements) can be provided to connect the outer shell to the shock absorbing layer.

Claims (20)

A helmet, the helmet comprising:
A shock absorbing layer;
an outer shell mounted on an outer surface of the impact absorbing layer;
a connector connecting the outer shell to the shock absorbing layer to maintain the outer shell on the shock absorbing layer;
the connectors being positioned to allow the outer shell to separate from the impact absorbing layer when the helmet is subjected to an impact;
The helmet, wherein the connector includes a plug, the plug extending between the outer shell and the impact absorbing layer, the outer shell including an aperture for receiving the plug, the plug extending through the aperture and attached to the impact absorbing layer such that the plug is accessible from outside the outer shell . The helmet according to claim 1, wherein the impact absorbing layer includes a hollow cell structure. The helmet according to claim 1 or 2, wherein the outer shell is formed from a rigid material. 4. The helmet of claim 1, wherein the outer shell has one of a thickness of less than 6 mm, a thickness of less than 4 mm , a thickness of less than 2 mm , a thickness of less than 0.5 mm. A helmet according to any one of claims 1 to 4, wherein the connectors are arranged to allow the outer shell to separate from the impact absorbing layer when the helmet is subjected to an impact having a particular force. 6. The helmet according to claim 1, wherein the connector extends along a central axis of symmetry of the helmet. The helmet according to any one of claims 1 to 6, wherein the connector is positioned at the front of the helmet. The helmet of any one of claims 1 to 7, wherein the connector comprises a separate component from the outer shell and the impact absorbing layer. A helmet according to any one of claims 1 to 8, 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 subjected to an impact. The helmet of claim 1 , wherein the connector includes a socket for receiving the plug of the connector. The helmet of claim 10 , wherein the socket is formed on or attached to the outer surface of the impact absorbing layer. 12. A helmet as claimed in claim 10 or 11 , wherein the plug and the socket are attached via a push-fit. 13. A helmet according to any one of claims 1 to 12 , wherein the plug includes an outer head having a dimension greater than a corresponding dimension of the aperture. 8. The helmet of claim 1 , wherein the connector includes a protrusion, the protrusion being integral with the impact absorbing layer. 15. The helmet of claim 14 , wherein the projections are attached to the main body portion of the impact absorbing layer by flexible portions. 16. The helmet according to claim 14 or 15 , wherein the impact absorbing layer includes a cavity arranged to receive the protrusion. 17. A helmet according to any one of claims 14 to 16 , wherein the outer shell includes an aperture for receiving the protrusion. 18. The helmet of any one of claims 1 to 17, wherein the impact absorbing layer includes at least one groove formed therein, and the outer shell includes at least one inwardly protruding ridge, the at least one ridge positioned to engage the at least one groove when the outer shell is fitted over the impact absorbing layer. 20. The helmet of claim 18, wherein the at least one ridge and the at least one groove are positioned such that a particular force is required to remove the at least one ridge from the at least one groove. 20. The helmet according to any one of claims 1 to 19 , wherein the connector extends radially relative to the impact absorbing layer.

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