TECHNICAL FIELD

The present disclosure relates to an impact attenuation system.

More particularly, the present disclosure relates to an impact attenuation system to protect a person or a structure from injury or damage from impact shocks. The impact attenuation system can be utilised in helmets for athletes, mountaineers, motorcycle riders and any other persons who are prone to suffering head collisions, as well as in body armour.

BACKGROUND

Impact shocks have the tendency to cause great damage to the impacted body in whichever environment the impact takes place. In terms of human injury, a person’s head is most prone to sustain injury from such impact shocks, leading to concussion and brain injury. However, also buildings and other physical structures are often damaged by impact shocks.

A helmet is a form of protective gear worn to protect the head, more particularly to protect the human brain from injury following an impact shock. Helmets are used for recreational activities and sports (e.g. football codes including soccer, AFL (Australian Football League), rugby union and rugby league, jockeys in horse racing, American football, ice hockey, cricket, baseball, camogie, hurling and rock climbing); dangerous work activities such as construction, mining, riot police, military aviation, and in transportation (e.g. motorcycle helmets and bicycle helmets).

Some sporting helmets are made of a flexible foam, for example such as EVA foam (EVA foam is a closed cell ethylene-vinyl acetate copolymer foam), and are used in sports where there is a need to also protect the item impacting the head, e.g. in boxing and rugby or football. Other sporting helmets have an outer hard shell enclosing a flexible or rigid foam inside the helmet, e.g. bicycle helmets, motorbike helmets, and American football helmets. The hard shell resists breaking on impact, while the internal flexible or rigid foam cushions the impact of the hard shell against the head. In modern sports, a great emphasis is being placed on concussion safety. When a player’s head is impacted by an impact shock, the head and brain experiences G-forces which can lead to a concussion injury - the severity of the injury is dependent on the velocity of the impact shock as well as the mass, angle and location of the impact shock. Rotational motion is a common cause of concussions and more severe brain injury in oblique hits to the head. The impact shock, and the damage caused thereby, can be reduced by attenuating the impact time and the force and/or direction of the impact shock.

The MIPS system is a well-known example of a device designed to try and reduce rotational acceleration applied by an impact shock. Essentially, MIPS is a thin low-friction plastic liner inside a helmet that is designed to move slightly inside the helmet to help redirect forces away from the head. However, the effectiveness of the MIPS system tends to be limited to certain angles as it doesn’t work effectively against impact shocks from all angles and has no ability to absorb any impact shock.

To at least partially attenuate the damage caused by an impact shock it is necessary to improve angular acceleration management and/or to decelerate and attenuate the impact force.

The above references to the background art and any prior art citations do not constitute an admission that the art forms part of the common general knowledge of a person of ordinary skill in the art.

SUMMARY OF THE DISCLOSURE

According to the disclosure, there is provided an impact attenuation system. The impact attenuation system is arranged to protect a person or structure from injury or damage from impact shocks. The impact attenuation system can be utilised in helmets for athletes, mountaineers, motorcycle riders and any other persons who are prone to suffering head collisions, as well as in body armour.

According to a first aspect of the disclosure, there is provided an impact attenuation system for protecting an underlying structure, being a part of a person or a structure, from injury or damage resulting from impact shocks, the impact attenuation system comprising a multiplicity of nodes arranged in a nodal matrix, wherein each of the nodes is interlinked with its neighbouring nodes, and wherein each node is able to at least partially rotate relative to each other node within the nodal matrix.

The nodal matrix may include a single layer of nodes arranged in a triangular matrix.

In one example each node has a crown in the form of a ridge protruding from the node and wherein the crown is directed towards an operative outer side of the node. Each node may have a node cap mounted on the crown, whereby the node cap is arranged to outwardly cover the node. Each node cap may have a peripheral lip arranged to extend over an edge of the crown. In one example, each node has a node cap mounted on the node with the node cap being directed towards an operative outer side of the node. The node cap may be arranged to cover the outer side of the node. Each node cap may be made of a rigid plastics material.

In one example each node has a geometrical shape selected from the group of: a solid spherical node, a segmented or tessellated spherical node, an ovoid node, a pedestalshaped node, and an hourglass-shaped node. Each node may have an equatorial recessed groove. Each node may be made of either flexible foam, rigid foam, liquid crystal elastomers, hollow elastomer balls, or air-pressurized hollow elastomer balls.

In one example the nodal matrix is enclosed by an edge border that includes an embedded wire skeleton, wherein the wire skeleton is made of a resilient material having a high yield strength.

In one example each node is in abutting contact with its neighbouring nodes. Each node may be integrally formed with each abutting neighbouring node.

In one example each node is spaced apart from but interconnected with its neighbouring nodes. In one example the nodes are interconnected by lattice bars that are integrally formed with the nodes.

In one example the impact attenuation system further includes a lattice web having a number of strands arranged in a lattice structure that intersect at intersections, wherein the nodes are mounted on the lattice web at each of the intersections. The nodes may be over-moulded or clip-fitted onto the intersections of the lattice web. Alternatively, the nodes may be pre-formed in connectable separate parts having engageable male pins and female sockets enabling the nodes to be clipped together over the intersections of the lattice web.

In one example the impact attenuation system further includes a rigid or flexible frame structure defining a number of through-holes, whereby one of the nodes can be located within each of the through-holes. A part of the frame structure surrounding each through-hole may be received within an equatorial groove in the node located within that through hole.

The nodes may be spaced apart within the nodal matrix with the spacing between the centres of neighbouring nodes being about 80%-130% of the nominal cross-sectional width of one of the nodes. In nodes having a substantially spherical shape the nominal cross-sectional width of one of the nodes is its diameter.

In one example the nodal matrix may be arranged in the form of a helmet for protecting a person’s head. In another example the nodal matrix may be arranged in the form of an internal lining or padding provided within a conventional helmet or hardhat. In one example the nodal matrix may be arranged in the form of body armour to be worn on a person’s body to protect a part of the person’s body. In one example the nodal matrix may be arranged in the form of a protective layer to protect a part of a building or physical structure. During use, when the nodes are impacted by an impact shock, the nodes may be arranged at least partially to rotate within the nodal matrix and roll along the underlying structure.

The nodes may be made of a resilient compressible material that has an increasing resistance to compression as the nodes are compressed by an impact shock. The nodes may be made of a resilient compressible material having a variable density across the height of the nodes extending away from the underlying surface, wherein the resilient compressible material includes lower density foam nearer to the underlying surface and higher density foam farther from the underlying surface.

According to a second aspect of the disclosure, there is provided a helmet for a person’s head, the helmet being arranged to at least partially surround the person’s head, the helmet comprising a multiplicity of nodes arranged in a nodal matrix, wherein each of the nodes is interlinked with its neighbouring nodes, and wherein each node is able to at least partially rotate relative to each other node within the nodal matrix, whereby in use when an impact shock impacts against one or more of the nodes, the impacted nodes are able at least partially to rotate and roll around the person’s head.

The helmet may include the impact attenuation system as defined in the first aspect of the disclosure. The helmet may be arranged in the form of an internal lining or padding provided within a conventional helmet or hardhat.

BRIEF DESCRIPTION OF DRAWINGS

The above and other features will become more apparent from the following description with reference to the accompanying schematic drawings. In the drawings, which are given for purpose of illustration only and are not intended to be in any way limiting:

Figure 1 is a perspective view of a first embodiment of a helmet incorporating the impact attenuation system according to the disclosure, wherein the impact attenuation system includes a multiplicity of nodes interlinked in a spaced nodal matrix as shown in the enlarged blow-out balloon section view;

Figure 2 is a perspective view of a second embodiment of a helmet, incorporating the impact attenuation system according to the disclosure, wherein the impact attenuation system includes a multiplicity of nodes interlinked in a condensed nodal matrix as shown in the enlarged blow-out balloon section view;

Figure 3 is a perspective view of a third embodiment of a helmet that is similar to the helmet of Figure 1 , but wherein the nodes of the spaced nodal matrix are provided with node caps as shown in the enlarged blow-out balloon section view;

Figures 4 is a partial view of the helmet of Figure 1 , wherein only an edge border of the nodal matrix is shown;

Figure 5 is a schematic side view of the helmet of Figure 1 , wherein the helmet is provided as a lining or padding inside a hardhat;

Figures 6A - 6F show side views of various embodiments of different types of nodes that can be used in the nodal matrix shown in Figures 1 and 2;

Figures 7A - 7C show side views of various embodiments of different types of nodes that can be used in the nodal matrix shown in Figure 3;

Figure 8 shows a perspective view of a part of the condensed nodal matrix shown in the helmet of Figure 2;

Figure 9 shows a perspective view of a part of the spaced nodal matrix shown in the helmet of Figure 3;

Figure 10 shows a perspective view of a part of another embodiment of a spaced nodal matrix, wherein the nodes are able to be removably secured to a lattice web and wherein the nodes are shaped as shown in Figure 1;

Figure 11 shows an exploded perspective view of the nodal matrix of Figure 10, but wherein the nodes are shaped as shown in Figure 6A;

Figure 12 shows a perspective view of a part of another embodiment of a spaced nodal matrix, wherein the nodes are able to be removably secured to a frame structure;

Figures 13A - 13C show schematic plan views of various nodal matrixes having nodes with different nominal widths and arranged in different nodal spacings;

Figure 14 shows schematic cross-sectional views of a node, such as the embodiment shown in Figure 6A, in various stages of deformation under increasing orthogonal compression forces;

Figure 15 shows schematic cross-sectional views of a series of nodes, such as the embodiment shown in Figure 6A, in various stages of deformation under increasing oblique compression forces;

Figure 16 shows a chart of a compression resistance curve and an impact force deceleration curve plotted against the degree of compression; and

Figures 17A - 17C show the use of the impact attenuation system in various other applications such as body armour in the form of a chest plate and shin guards, and on crash barriers.

DETAILED DESCRIPTION

The present disclosure relates to an impact attenuation system. The impact attenuation system is arranged to protect a person or a structure from injury or damage resulting from impact shocks. The impact attenuation system can be utilised in helmets for athletes, mountaineers, motorcycle riders and any other persons who are prone to suffering head collisions, as well as in body armour. The impact attenuation system is particularly adapted to attenuate an impact time and force and/or direction of an impact shock imparted to a person’s head or body.

Figure 1 of the drawings shows a first embodiment of a helmet 110 that is arranged to be worn on a person’s head 100. The helmet 110 incorporates an impact attenuation system 102 that includes a multiplicity of nodes 112 that are interlinked with each other in a nodal matrix 114. The nodal matrix 114 has a peripheral edge border 116 that can be attached to straps 118, such as chin straps, for securing the helmet 110 on the person’s head 100. As can be seen in Figure 1 , the nodes 112 are spaced apart and arranged in a triangular matrix, wherein the nodes 112 do not abut against each other, but wherein each of the nodes 112 is interlinked with its neighbouring node by lattice bars 120. Although the lattice bars 120 are represented as tubular bars, they can also have other geometrical cross-sections such as square, rectangular or elliptical bars. Each node 112 is substantially spherical in shape having an outwardly directed crown 122 in the form of a protruding ridge that is hexagonal in shape. Each crown 122 can be integrally formed with its node 112. In this embodiment the shape of the crown 122 is only aesthetic and has no functional purpose, however, in other embodiments ( as described below) the crown may have certain functions.

The helmet 110 Is manufactured from a uniform material throughout so that the nodes 112 and lattice bars 120 are made of the same material. The helmet 110 is manufactured from a soft foam that is compressive and resilient, e.g. EVA foam.

Figure 2 shows a second embodiment of a helmet 210 that is arranged to be worn on a person’s head 100. The helmet 210 is substantially similar to the helmet 110 and equivalent parts are indicated by the same reference numerals. The helmet 210 includes a multiplicity of nodes 112 that are interlinked with each other in a nodal matrix 114. The nodal matrix 114 has a peripheral edge border 116 that can be attached to straps 118, such as chin straps, for securing the helmet 210 on the person’s head 100. The helmet 210 has a chin guard 124 joined to the straps 118, wherein the chin guard 124 is shaped complementary to a person’s jawline and generally has a nodal matrix enclosed by a peripheral edge border.

As can be seen in Figure 2, in this embodiment the nodes 112 are substantially spherical in shape and arranged in a condensed triangular matrix wherein the nodes 112 directly abut against and are joined to each neighbouring node. In some examples the nodes 112 can be integrally joined together.

The helmet 210 is manufactured from a uniform material throughout. The helmet 210 is manufactured from a soft foam that is compressive and resilient, e.g. EVA foam.

Figure 3 shows a third embodiment of a helmet 310 that is arranged to be worn on a person’s head 100. The helmet 310 is substantially similar to the helmet 110 and equivalent parts are indicated by the same reference numerals. The helmet 310 also has a chin guard 124 similar to that shown in Figure 2. The nodes 112 of the third embodiment are provided with outer node caps 126 that seat onto the crown 122. In contrast to the soft foam of which the nodes 112 and lattice bars 120 are made, the node caps 126 are made of rigid plastics material that is arranged to constitute a hardshell.

Referring now to Figure 4, there is shown only a partial schematic view of the edge border 116 of the first embodiment of the helmet 110 with the remaining parts of the helmet omitted for clarity and simplicity. The edge border 116 is shown including an embedded wire skeleton 128. In one example the wire skeleton 128 extends along the full length of the edge border 116 so that it fully encircles the head 100. However, in other examples, the wire skeleton 128 can be provided only along intermittent sections of the edge border 116 as needed. The wire skeleton 128 is made of a resilient material, for example such as spring steel or carbon fibre having a high yield strength. The resilience of the wire skeleton 128 allows the edge border 116 of the helmet 110 to be pushed open by a person to enable them to place the helmet 110 on their head 100, whereafter the wire skeleton 128 will “snap” back to (or largely to) its original shape and thereby hold the helmet 110 onto the person’s head 100 under a friction fit and without the need for straps 118. The fitting of the helmet 110 onto person’s head and the strength of the friction fit can be enhanced by extending the forward cheek flaps of the helmet 110 to at least partially enclose the person’s cheek bones or jaw. It should be appreciated that the provision of the wire skeleton 128 and its friction fit can also be applied in the second and third embodiment of the helmet 210, 310.

Apart from being used as a piece standalone protective headgear, either of or any part of the helmets 110, 210 can also be used as an internal lining or padding within a conventional type of hardhat, e.g. an industrial hardhat or a hard helmet such as a motorbike helmet, bicycle helmet, American football helmet, etc. Figure 5 shows a schematic cross-sectional side view of such a hardhat 130 with the helmet 110 provided as an internal lining therein to provide better impact protection, whether from direct orthogonal or oblique impact shocks.

In each of the above-described embodiments of the helmet 110, 210, 310, the nodes 112 can be selected to have one of several different types or shapes. Examples of such differently shaped nodes are shown in Figures 6A-6F, wherein:

- Figure 6A shows a solid spherical ball shaped node 132. - Figure 6B shows a segmented or tessellated spherical ball shaped node 134. In one example the node 134 can have a honeycomb geometrical structure. In another example the node 134 can be any n-gonal hosohedron being a tessellation of lunes on a spherical surface, such that each lune shares the same two polar opposite vertices. In the exemplary embodiment the node 134 is square hosohedron.

- Figure 6C shows an ovoid shaped node 136 having it greatest girth in the outer/upper half of the node as shown by reference numeral 138, i.e. which greatest girth 138 will be spaced concentrically farthest from the head 100 in use. Such an ovoid shape allows the nodes 112 to more fully cover the person’s head 100 and reduce the formation of outer gaps that may occur using spherical balls.

- Figure 6D shows a substantially spherical ball shaped node 140 having an equatorial recessed groove 142 and a circular crown 144.

- Figure 6E shows a pedestal shaped node 146 having a mushroom-like appearance, which can be formed by inverting a lower hemisphere of a spherical node.

- Figure 6F shows an hourglass-shaped node 148, which can be formed by inverting both an upper and a lower hemisphere of a spherical node.

However it should be appreciated that other shaped nodes can also be used in the nodal matrix 114. The nodes 112 can be made of flexible foam, rigid foam, liquid crystal elastomers, or hollow elastomer balls (optionally that may be pressurized). In one example the nodes 112 can be made of solid, hollow or 3D lattice structured liquid crystal elastomers. In another example the nodes 112 are air-pressurized hollow elastomer balls, e.g. similar to miniature stress balls or squash balls. Such nodes 112 may be pressurized to an optimal pressure for impact absorption, potentially creating a pneumatic impact system. Additionally, when compared to foams, the elastomer skins (such as polyurethane) of elastomer balls may display superior surface toughness against abrasive mechanical impact.

Furthermore, in each of the above-described embodiments of the helmet 110, 210, 310, the nodes 112 can be provided with the node caps 126, i.e. also the helmets 110 and 210 can be provided with node caps 126 similar to those shown in the helmet 310 of Figure 3. Examples of such nodes 112 with node caps 126 are shown in Figures 7A-7C, wherein:

- Figure 7A shows a spherical ball shaped node 140 provided with a saucer shaped node cap 150 having an out-turned circular perimeter 152;

- Figure 7B shows a spherical ball shaped node 154 with a hexagonal crown 156, i.e. being similar to the nodes 112 shown in Figure 1, and provided with a node cap 158 having a hexagonal perimeter 160;

- Figure 7C shows a spherical ball shaped node 162 having an equatorial groove 164 and a hexagonal crown 166 provided with a node cap 168 having a hexagonal perimeter 170, i.e. the node 162 and node cap 168 are similar to the nodes 112 shown in Figure 3 but with the node 162 having an equatorial groove 164 as shown in Figure 6D. The hexagonal perimeter 170 has a depending peripheral lip 172 that is arranged to extend over an edge of the hexagonal crown 166 thereby to locate the node cap 168 more securely. In the exemplary embodiment the edge of the hexagonal crown 166 has a rabbeted recess so that the peripheral lip 172 can be received therein without protruding beyond the hexagonal crown 166.

In one embodiment the node caps 126 are hexagonal in shape when seen in plan view, i.e. orthogonal to the person’s head 100. The use of hexagonal node caps 126 allows the node caps 126 to be tessellated on the helmet 110 thereby being able to be packed relatively closely together and provide a large degree of covering over the outer surface of the helmet 310. It will be appreciated that other shaped node caps 126 will also allow similar tessellation.

The provision of the crown 122 on the nodes 112 permits a more secure attachment of the node caps 126 to the nodes 112.

Referring now to Figures 8 through 12, there are shown various examples for joining the nodes 112 together in the nodal matrix 114. The nodal matrix 114 is generally a sheet having a single layer of nodes 112. When the nodal matrix 114 is manufactured as a flat sheet, the nodes 112 will be arranged generally co-planarly with each other, however it should be appreciated that due to the flexibility of the material from which the nodes 112 and/or the interconnecting lattice bars 120 are made, it is possible to bend the nodal matrix 114 into any desired shape, e.g. a shape defining the helmet 110, a helmet liner, or a part of body armour. Alternatively, the nodal matrix 114 can be moulded directly in the requisite shape, e.g. that of the helmet 110. In the Figures 8-12 only a part of the nodal matrix 114 is shown and it should be appreciated that the matrix can be extended to obtain the desired planar size. In the exemplary embodiment the nodal matrix 114 is arranged in a triangular matrix as that allows for the maximum number of spherical nodes 112 to be provided in any given area. In Figure 8 there is shown a first embodiment of the nodal matrix 114 wherein the nodes 112 are spherical ball shaped nodes that abut directly against their neighbouring nodes in a condensed matrix. In some instances, the nodes 112 can be joined at a circumferential I tangential contact point with their neighbouring nodes 112, but such a small contact area may result in a weak joint between the neighbouring nodes 112. As shown in Figure 8, a more secure bond can be obtained by having the nodes 112 intersect I overlap so that neighbouring nodes 112 can be joined together along a desired spherical segment of their circumference to provide a larger contact area. In Figure 8 the spacing between the centres of neighbouring nodes 112 will be <100% and typically be about 80%-90% of the nominal cross-sectional width of one of the nodes 112 (e.g. the diameter of a spherical node). The nodal matrix 114 shown in Figure 8 is moulded as a single part. The use of the condensed nodal matrix 114 is shown in the helmet 110 of Figure 2.

In Figure 9 there is shown a second embodiment of the nodal matrix 114 wherein the nodes 112 are spherical ball shaped nodes each having the hexagonal crown 122 that is provided with the node cap 126. The nodes 112 are spaced apart from each other in a spaced matrix, whereby each of the nodes 112 is interlinked with its neighbouring nodes 112 by lattice bars 120. The lattice bars 120 have a cylindrical shape and have a diameter being about 20%-50% of the diameter of the nodes 112. The axial length of the lattice bars 120 can be selected to obtain the desired spacing between the centres of neighbouring nodes 112. In Figure 9, the spacing between the centres of neighbouring nodes 112 will be >100% and typically be about 105%-130% of the nominal cross-sectional width of one of the nodes 112 (e.g. the diameter of a spherical node). As previously mentioned, although the lattice bars 120 are represented as tubular bars, they can also have other geometrical cross-sections such as square, rectangular or elliptical bars. The nodal matrix 114 shown in Figure 9 is moulded as a single part, apart from the node caps 126 which are joined to their respective nodes 112 later in the production process, for example by bonding or over-moulding.

In Figures 10 and 11 there is shown a third embodiment of the nodal matrix 114 wherein the nodes 112 are spherical ball shaped nodes each having an outer hexagonal crown 122. The nodes 112 are spaced apart from each other in a spaced matrix, whereby each of the nodes 112 is joined to a flexible lattice web 174 (seen more clearly in Figure 11). The lattice web 174 has strands 176 arranged in a triangular lattice structure, but it should be appreciated that other shaped lattice structures could also be used, e.g. a square lattice web or a diamond lattice web. The strands 176 of the lattice web 174 have a diameter being about 5%-20% of the diameter of the nodes 112. The lattice web 174 can be made of any material that is stretchy but tough and resilient, such as polyurethane elastomer. The nodes 112 are joined to the lattice web 174 at each of the intersections 178 of the strands 176 so that the centre of each node 112 lies on its associated intersection 178. The spacing of the intersections 178 of the lattice web 174 can be selected to obtain the desired spacing between the centres of neighbouring nodes 112. In Figures 10 and 11, the spacing between the centres of neighbouring nodes 112 will be >100% and typically be about 105%-130% of the nominal cross-sectional width of one of the nodes 112 (e.g. the diameter of a spherical node). In some embodiments, as shown in Figure 10, the nodes 112 can be over-moulded as a single part onto the intersections 178 of the lattice web 174. In another embodiment the nodes 112 can be clip-fitted onto the intersections 178 of the lattice web 174. In yet another embodiment, as shown in Figure 11, the nodes 112 can be pre-formed in connectable separate hemispheres 180 that can be clipped over the intersections 178 of the lattice web 174 - in such case the hemispheres 180 will have suitable male pins 182 for engaging into female sockets 184 (although the skilled addresses will appreciate that also other types of mechanical connections could be used).

In Figure 12 there is shown a fourth embodiment of the nodal matrix 114 wherein the nodes 112 are of the type shown in Figure 7C, i.e. spherical ball shaped nodes 162 each having the equatorial groove 164 and the hexagonal crown 166 and being provided with the node cap 168. The nodal matrix 114 includes a flexible frame structure 186 defining a number of through-holes 188, whereby each of the nodes 162 can be located into one of the through-holes 188 so that the frame structure 186 is received within its equatorial groove 164. Accordingly, the through-holes 188 and the equatorial grooves 164 are complementary in shape - in the exemplary embodiment the through-holes 188 and equatorial grooves 164 have a hexagonal shape, but they could also be round or square shaped. The spacing of the through-holes 188 in the frame structure 186 can be selected to obtain the desired spacing between the centres of neighbouring nodes 162. In Figure 12, the spacing between the centres of neighbouring nodes 112 will be >100% and typically be about 105%-130% of the nominal cross-sectional width of one of the nodes 112 (e.g. the diameter of a spherical node). In some examples, the frame structure 186 can be rigid if the nodes 114 are sufficiently resilient to allow a slight “rolling”" of the nodes 114 relative to the frame structure 186 when compressed under an impact shock.

The above described spacing between the centres of neighbouring nodes 112 is more clearly illustrated in Figures 13A-C showing various partial nodal matrixes 114 in plan view. Figure 13A shows the nodal matrix 114 of Figure 8, wherein the nodes 112 have a diameter / nominal width “NW” and wherein the nodal spacing “NS” is about 95% of the nominal width. Figure 13B shows the nodal matrix 114 of Figure 9, wherein the nodes 112 have a diameter I nominal width “NW’ and wherein the nodal spacing “NS” is about 110% of the nominal width. Figure 13C shows the nodal matrix 114 of Figure 12, wherein the nodes 112 have a diameter / nominal width “NW’ and wherein the nodal spacing “NS” is about 104% of the nominal width.

The description hereinafter will refer only to the helmet 110, but it can apply equally to the helmets 210 and 310.

In most head knocks, the impact shock is not solely directed radially towards the centre of mass of the person’s head 100. Rather the impact shock is directed obliquely to the person’s head 100 and includes both radial and tangential impact forces.

In one example the helmet 110 can be used as a standalone piece of headgear, as shown in Figures 1 and 2. When an impact shock is applied to the helmet 110, the nodal matrix 114 functions to reduce both the magnitude and the rotational momentum of the impact force. This is achieved because the nodes 112 and the nodal matrix 114 are able to deform, both to cushion the impact force while the nodes 112 are able to at least slightly rotate or roll relative to each other within the nodal matrix 114, i.e. when the impact shock is applied to the person’s head 100, the nodes 112 can be compressed and also roll slightly around the wearer’s head.

In another example the helmet 110 can be used as a liner inside a conventional hardhat 130, as shown in Figure 5. The main protection afforded by conventional hardhats 130 is against direct blows from rigid objects. For example, impact with a car, road, barrier etc. However, conventional hardhats 130 are not good at resisting concussion simply because an impact shock to any point of the hardhat 130 results in the entire hardhat 130 reacting to the blow - i.e. the person’s head 100 is rapidly accelerated by the impact force - and this is what needs to be avoided to prevent concussion. When an angular impact shock strikes the outside of a hardhat 130 that is lined with the helmet 110, the hardhat 130 will still rotate as an entity, but the hardhat 130 will press onto the nodes 112 in a discrete area causing the nodes 112 in that area to rotate and roll relative to the person’s head 100 and thereby resulting in the person’s head rotating to a lesser degree and attenuating the acceleration of the head caused by the oblique contact of the impact shock onto the hardhat 130.

Alternatively, the helmet 310 can be used as a standalone piece of headgear, as shown in Figure 5, which incorporates features of both the helmet 110 and the hardhat 130. By providing the hard plastic node caps 126 on the outer side of the nodes 112, the node caps 126 act like the protective scales of a pangolin. Such a segmented hard-shell structure localizes the area receiving the impact shock and thus the entire head/helmet is not accelerated in response thereto. The impact force is decelerated, absorbed and attenuated through the nodes 112 and nodal matrix 114 in the localized area of the impact shock.

The degree or distance that the nodes 112 can roll around the person’s head 100 is impacted by the size of the nodes 112. The flexibility of the nodal matrix 114 and the degree or distance that the nodes 112 can rotate and roll around the person’s head 100 is also impacted by the spacing between the nodes 112 and the matrix structure. It will be appreciated that in a nodal matrix 114 as shown in Figure 8 the nodes 112 will be able to experience a minimal degree of roll I rotation and the nodal matrix 114 will have a low flexibility. In a nodal matrix 114 as shown in Figure 9 the nodes 112 will be able to experience a moderate degree of roll I rotation and the nodal matrix 114 will have a moderate flexibility. In a nodal matrix 114 as shown in Figures 10 to 12 the nodes 112 will be able to experience a large degree of roll I rotation and the nodal matrix 114 will have a high flexibility.

The high flexibility of the nodal matrix shown in Figures 10 to 12 have the benefit of enabling the helmet 110 to better form-fit each person’s head 100 and to collapse almost flat when being stored. In addition to the use in the helmet 110, the matrix 114 shown in Figures 10 to 12 is also suited for use in body armour applications, particularly because of the high flexibility of the lattice web 174 and the large degree of roll / rotation of the nodes 112. The nodes 112 have a geometry that results in inherently progressive resistance to the impact force as the nodes 112 become compressed. In other words, as the impact force is increased on one or more of the nodes 112, the initial compression and resistance to the compression that is exerted by those nodes 112 is low, but as the nodes 112 become more compressed under increasing impact force the nodes 112 deform in shape to become more ellipsoid (oblate spheroid) thereby providing an increasingly progressive resistance to the impact force. Effectively, this is because the central cross-section of the nodes 112 increases in area.

The change in the geometry of the nodes 112 is illustrated in Figures 14 and 15 with the resultant effect displayed in the graph shown in Figure 16.

Figure 14 shows comparative schematic cross-sectional views of a single node 112 in various stages of deformation under increasing orthogonal compression forces 190, i.e. as would be radially I perpendicularly impacting a person’s head 100. The node 112.1 experiences a low impact force and displays minimal deformation remaining substantially spherical. The node 112.2 experiences a medium impact force and displays moderate deformation to become more ellipsoid. The node 112.3 experiences a large impact force and displays severe deformation to become very ellipsoid. As the deformation of the node 112 increases, its resistance to further deformation and thus its resistance to the impact force increases.

Figure 15 shows comparative schematic cross-sectional views of three neighbouring nodes 112 in various stages of deformation under increasing oblique compression forces 192, i.e. angular impact forces impacting a person’s head 100. In addition to the compression of the nodes 112 described in Figure 14, the tangential vector of the impact force also causes the nodes 112 to roll and rotate slightly around the person’s head 100. Thus the node 112.1 experiences minimal tangential displacement, while the node 112.2 experiences moderate tangential displacement, and the node 112.3 experiences large tangential displacement. The rolling can be seen by the displace of the static surface point 194 shown in the node 112.

Figure 16 shows a graph of a compression resistance curve and an impact force deceleration curve plotted against degree of compression. The graphed compression curve 196 shows that as a node 112 is compressed (the X axis) its initial resistance to compression (the Y axis) is very low but then the resistance to compression progressively increases. The resultant impact deceleration curve 198 is the inverse of that curve, because the impact velocity is initially high but then progressively decreases. This progressive deceleration of the impact force reduces the chances of concussion or head injury.

The compression of the nodes 112 and their ability to roll and rotate relative to each other within the nodal matrix 114 spreads and attenuates the impact forces via deformation and work thereby reducing the magnitude of the impact forces.

All the geometrical shapes of the nodes 112 shown in Figure 6 essentially perform in an equivalent manner to that of a simple sphere when experiencing an orthogonal impact, with the progressive resistance and deceleration as described above being inherent in all the alternatives. The actual choice of which shape and/or type of nodes 112 to use is therefore largely determined by the specific desired practical application requirements.

Example 1

Laboratory testing of the nodal matrix 114 shown in Figures 1 and 2 was carried out at the New South Wales Government Crash-Lab of a rigid, medium density polystyrene foam block vs a block of the same density and thickness polystyrene foam spherical nodes. Both blocks were of the same thickness with identical 1 ,5mm thick polycarbonate skins on the top and bottom. The spherical node block had only 52% of the foam volume and 52% of the foam weight of the solid foam block because spherical balls are 52% of the volume of solid foam for the same thickness and perimeter.

The spherical node block displayed noticeably better results in attenuating the impact force in all the tests apart from a straight drop test. This is attributed thereto that with only 52% of the volume of foam, there was not quite enough foam to match the drop weight and height. However, with 48% less foam than the solid block, spherical node block was only 13% worse for straight drop impacts. In contrast the spherical node block was 50% better than the solid block even though it had only 52% of the foam volume. When corrected for volume/weight, the spherical node block is a factor of 3 times better than the foam block results for oblique impact forces. The improved attenuation of the oblique impact forces is attributed to the superior deceleration properties of the spherical nodes being able to rotate and roll (as described above). For the helmet 110 to be used as a football helmet, the nodes 112 are generally made of foam material such as EVA with a typical hardness of Shore A 35-40

(Asker C 55-65) - but these hardness values can be higher or lower. This hardness value generally corresponds with EVA foam densities above 100 kg/m3 but can of course vary according to proprietary EVA raw materials, etc. In some examples, each node 112 can be moulded with lower density foam in the inner part of the node 112 (i.e. that part to contact the person’s head 100) with higher density foam in the outer part of the node 112 (i.e. that part remote from the person’s head 100). This variable density combination has the perceived advantage of being more comfortable to wear because the softer foam is in contact with the person’s head 100 and also has a lower compression resistance (gentler initial deceleration from impact) because the lower density foam compresses first, followed by compression of the outer higher density foam.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the impact attenuation system as shown in the specific embodiments without departing from the spirit or scope of the disclosure as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

For example, most of the description above of the impact attenuation system 102 relates to its use in the helmets 110, however the impact attenuation system 102 has many other applications and can, for example, also be used in body armour, amongst others such as a chest plate as shown in Figure 17A and a shin guard as shown in Figure 17B. The body armour can include shoulder pads and gloves, such as cricket gloves.

Alternatively, the impact attenuation system 102 can also be used to protect structures and/or buildings from impact shocks and can, for example, also be used for crash barriers as shown in Figure 17C.

In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in a non-limiting and an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in the various embodiments. A reference to an element by the indefinite article “a" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements.

Reference numerals

100 head 156 hexagonal crown

102 impact attenuation system 158 node cap

110 helmet 160 hexagonal perimeter

210 helmet 162 ball shaped node

310 helmet 164 equatorial groove

112 nodes 166 hexagonal crown

114 nodal matrix 168 node cap

116 edge border 170 hexagonal perimeter

118 straps 172 lip

120 lattice bars 174 lattice web

122 crown 176 strands

124 chin guard 178 intersections

126 node caps 180 hemispheres

128 wire skeleton 182 pins

130 hardhat 184 sockets

132 solid ball shaped node 186 frame structure

134 segmented ball shaped node 188 through-holes

136 ovoid shaped node 190 orthogonal compression force

138 greatest girth 192 oblique compression force

140 ball shaped node 194 surface point

142 equatorial groove 196 compression curve

144 circular crown 198 deceleration curve

146 pedestal shaped node

148 hourglass shaped node NW nominal width of a node

150 saucer shaped node cap NS nodal spacing of a nodal matrix

152 circular perimeter

154 ball shaped node