Patent ID: 12256796

The proportions of the thicknesses of the various layers in the helmets depicted in the figures have been exaggerated in the drawings for the sake of clarity and can of course be adapted according to need and requirements.

FIG.1depicts a first helmet1of the sort discussed in WO 01/45526, intended for providing protection against oblique impacts. This type of helmet could be any of the types of helmet discussed above.

Protective helmet1is constructed with an outer shell2and, arranged inside the outer shell2, an inner shell3that is intended for contact with the head of the wearer.

Arranged between the outer shell2and the inner shell3is a sliding layer4or a sliding facilitator, and thus makes possible displacement between the outer shell2and the inner shell3. In particular, as discussed below, a sliding layer4or sliding facilitator may be configured such that sliding may occur between two parts during an impact. For example, it may be configured to enable sliding under forces associated with an impact on the helmet1that is expected to be survivable for the wearer of the helmet1. In some arrangements, it may be desirable to configure the sliding layer or sliding facilitator such that the coefficient of friction is between 0.001 and 0.3 and/or below 0.15.

Arranged in the edge portion of the helmet1, in theFIG.1depiction, may be one or more connecting members5which interconnect the outer shell2and the inner shell3. In some arrangements, the connectors may counteract mutual displacement between the outer shell2and the inner shell3by absorbing energy. However, this is not essential. Further, even where this feature is present, the amount of energy absorbed is usually minimal in comparison to the energy absorbed by the inner shell3during an impact. In other arrangements, connecting members5may not be present at all.

Further, the location of these connecting members5can be varied (for example, being positioned away from the edge portion, and connecting the outer shell2and the inner shell3through the sliding layer4).

The outer shell2is preferably relatively thin and strong so as to withstand impact of various types. The outer shell2could be made of a polymer material such as polycarbonate (PC), polyvinylchloride (PVC) or acrylonitrile butadiene styrene (ABS) for example. Advantageously, the polymer material can be fibre-reinforced, using materials such as glass-fibre, Aramid, Twaron, carbon-fibre or Kevlar.

The inner shell3is considerably thicker and acts as an energy absorbing layer. As such, it is capable of damping or absorbing impacts against the head. It can advantageously be made of foam material like expanded polystyrene (EPS), expanded polypropylene (EPP), expanded polyurethane (EPU), vinyl nitrile foam; or other materials forming a honeycomb-like structure, for example; or strain rate sensitive foams such as marketed under the brand-names Poron™ and D3O™. The construction can be varied in different ways, which emerge below, with, for example, a number of layers of different materials.

Inner shell3is designed for absorbing the energy of an impact. Other elements of the helmet1will absorb that energy to a limited extend (e.g. the hard outer shell2or so-called ‘comfort padding’ provided within the inner shell3), but that is not their primary purpose and their contribution to the energy absorption is minimal compared to the energy absorption of the inner shell3. Indeed, although some other elements such as comfort padding may be made of ‘compressible’ materials, and as such considered as ‘energy absorbing’ in other contexts, it is well recognised in the field of helmets that compressible materials are not necessarily ‘energy absorbing’ in the sense of absorbing a meaningful amount of energy during an impact, for the purposes of reducing the harm to the wearer of the helmet.

A number of different materials and embodiments can be used as the sliding layer4or sliding facilitator, for example oil, Teflon, microspheres, air, rubber, polycarbonate (PC), a fabric material such as felt, etc. Such a layer 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. The number of sliding layers and their positioning can also be varied, and an example of this is discussed below (with reference toFIG.3B).

As connecting members5, use can be made of, for example, deformable strips of plastic or metal which are anchored in the outer shell and the inner shell in a suitable manner.

FIG.2shows the functioning principle of protective helmet1, in which the helmet1and a skull10of a wearer are assumed to be semi-cylindrical, with the skull10being mounted on a longitudinal axis11. Torsional force and torque are transmitted to the skull10when the helmet1is subjected to an oblique impact K. The impact force K gives rise to both a tangential force KT and a radial force KR against the protective helmet1. In this particular context, only the helmet-rotating tangential force KT and its effect are of interest.

As can be seen, the force K gives rise to a displacement12of the outer shell2relative to the inner shell3, the connecting members5being deformed. A reduction in the torsional force transmitted to the skull10of roughly 25% can be obtained with such an arrangement. This is a result of the sliding motion between the inner shell3and the outer shell2reducing the amount of energy which is transferred into radial acceleration.

Sliding motion can also occur in the circumferential direction of the protective helmet1, although this is not depicted. This can be as a consequence of circumferential angular rotation between the outer shell2and the inner shell3(i.e. during an impact the outer shell2can be rotated by a circumferential angle relative to the inner shell3).

Other arrangements of the protective helmet1are also possible. A few possible variants are shown inFIG.3. InFIG.3a, the inner shell3is constructed from a relatively thin outer layer3″ and a relatively thick inner layer3′. The outer layer3″ is preferably harder than the inner layer3′, to help facilitate the sliding with respect to outer shell2. InFIG.3b, the inner shell3is constructed in the same manner as inFIG.3a. In this case, however, there are two sliding layers4, between which there is an intermediate shell6. The two sliding layers4can, if so desired, be embodied differently and made of different materials. One possibility, for example, is to have lower friction in the outer sliding layer than in the inner. InFIG.3c, the outer shell2is embodied differently to previously. In this case, a harder outer layer2″ covers a softer inner layer2′. The inner layer2′ may, for example, be the same material as the inner shell3.

FIG.4depicts a second helmet1of the sort discussed in WO 2011/139224, which is also intended for providing protection against oblique impacts. This type of helmet could also be any of the types of helmet discussed above.

InFIG.4, helmet1comprises an energy absorbing layer3, similar to the inner shell3of the helmet ofFIG.1. The outer surface of the energy absorbing layer3may be provided from the same material as the energy absorbing layer3(i.e. there may be no additional outer shell), or the outer surface could be a rigid shell2(seeFIG.5) equivalent to the outer shell2of the helmet shown inFIG.1. In that case, the rigid shell2may be made from a different material than the energy absorbing layer3. The helmet1ofFIG.4has a plurality of vents7, which are optional, extending through both the energy absorbing layer3and the outer shell2, thereby allowing airflow through the helmet1.

An attachment device13is provided, for attachment of the helmet1to a wearer's head. As previously discussed, this may be desirable when energy absorbing layer3and rigid shell2cannot be adjusted in size, as it allows for the different size heads to be accommodated by adjusting the size of the attachment device13. The attachment device13could be made of an elastic or semi-elastic polymer material, such as PC, ABS, PVC or PTFE, or a natural fibre material such as cotton cloth. For example, a cap of textile or a net could form the attachment device13.

Although the attachment device13is shown as comprising a headband portion with further strap portions extending from the front, back, left and right sides, the particular configuration of the attachment device13can vary according to the configuration of the helmet. In some cases the attachment device may be more like a continuous (shaped) sheet, perhaps with holes or gaps, e.g. corresponding to the positions of vents7, to allow air-flow through the helmet.

FIG.4also depicts an optional adjustment device6for adjusting the diameter of the head band of the attachment device13for the particular wearer. In other arrangements, the head band could be an elastic head band in which case the adjustment device6could be excluded.

A sliding facilitator4is provided radially inwards of the energy absorbing layer3. The sliding facilitator4is adapted to slide against the energy absorbing layer or against the attachment device13that is provided for attaching the helmet to a wearer's head.

The sliding facilitator4is provided to assist sliding of the energy absorbing layer3in relation to an attachment device13, in the same manner as discussed above. The sliding facilitator4may be a material having a low coefficient of friction, or may be coated with such a material.

As such, in theFIG.4helmet, the sliding facilitator may be provided on or integrated with the innermost sided of the energy absorbing layer3, facing the attachment device13.

However, it is equally conceivable that the sliding facilitator4may be provided on or integrated with the outer surface of the attachment device13, for the same purpose of providing slidability between the energy absorbing layer3and the attachment device13. That is, in particular arrangements, the attachment device13itself can be adapted to act as a sliding facilitator5and may comprise a low friction material.

In other words, the sliding facilitator4is provided radially inwards of the energy absorbing layer3. The sliding facilitator can also be provided radially outwards of the attachment device13.

When the attachment device13is formed as a cap or net (as discussed above), sliding facilitators4may be provided as patches of low friction material.

The low friction material may be a waxy polymer, such as PTFE, ABS, PVC, PC, Nylon, PFA, EEP, PE and UHMWPE, or a powder material which could be infused with a lubricant. The low friction material could be a fabric material. As discussed, this low friction material could be applied to either one, or both of the sliding facilitator and the energy absorbing layer

The attachment device13can be fixed to the energy absorbing layer3and/or the outer shell2by means of fixing members5, such as the four fixing members5a,5b,5cand5dinFIG.4. These may be adapted to absorb energy by deforming in an elastic, semi-elastic or plastic way. However, this is not essential. Further, even where this feature is present, the amount of energy absorbed is usually minimal in comparison to the energy absorbed by the energy absorbing layer3during an impact.

According to the embodiment shown inFIG.4the four fixing members5a,5b,5cand5dare suspension members5a,5b,5c,5d, having first and second portions8,9, wherein the first portions8of the suspension members5a,5b,5c,5dare adapted to be fixed to the attachment device13, and the second portions9of the suspension members5a,5b,5c,5dare adapted to be fixed to the energy absorbing layer3.

FIG.5shows an embodiment of a helmet similar to the helmet inFIG.4, when placed on a wearers' head. The helmet1ofFIG.5comprises a hard outer shell2made from a different material than the energy absorbing layer3. In contrast toFIG.4, inFIG.5the attachment device13is fixed to the energy absorbing layer3by means of two fixing members5a,5b, which are adapted to absorb energy and forces elastically, semi-elastically or plastically.

A frontal oblique impact I creating a rotational force to the helmet is shown inFIG.5. The oblique impact I causes the energy absorbing layer3to slide in relation to the attachment device13. The attachment device13is fixed to the energy absorbing layer3by means of the fixing members5a,5b. Although only two such fixing members are shown, for the sake of clarity, in practice many such fixing members may be present. The fixing members5can absorb the rotational forces by deforming elastically or semi-elastically. In other arrangements, the deformation may be plastic, even resulting in the severing of one or more of the fixing members5. In the case of plastic deformation, at least the fixing members5will need to be replaced after an impact. In some case a combination of plastic and elastic deformation in the fixing members5may occur, i.e. some fixing members5rupture, absorbing energy plastically, whilst other fixing members deform and absorb forces elastically.

In general, in the helmets ofFIG.4andFIG.5, during an impact the energy absorbing layer3acts as an impact absorber by compressing, in the same way as the inner shell of theFIG.1helmet. If an outer shell2is used, it will help spread out the impact energy over the energy absorbing layer3. The sliding facilitator4will also allow sliding between the attachment device and the energy absorbing layer. This allows for a controlled way to dissipate energy that would otherwise be transmitted as rotational energy to the brain. The energy can be dissipated by friction heat, energy absorbing layer deformation or deformation or displacement of the fixing members. The reduced energy transmission results in reduced rotational acceleration affecting the brain, thus reducing the rotation of the brain within the skull. The risk of rotational injuries including MTBI and STBI such as subdural haematomas, SDH, blood vessel rapturing, concussions and DAI is thereby reduced.

Connectors of the present invention for connecting two parts of an apparatus are described below. It should be appreciated that these connectors may be used in a variety of contexts and are not be limited to use within helmets. For example, they may be used in other devices that provide impact protection, such as body armour or padding for sports equipment. In the context of helmets, the connectors of the present invention may, in particular, be used in place of the previously known connecting members and/or fixing members of the arrangements discussed above.

In an embodiment of the invention, the connector may be used with a helmet1of the type shown inFIG.6. The helmet shown inFIG.6has a similar configuration to that discussed above in respect ofFIGS.4and5. In particular, the helmet has a relatively hard outer shell2and an energy absorbing layer3. A head attachment device is provided in the form of a helmet liner15. The liner15may include comfort padding as discussed above. In general, the liner15and/or any comfort padding may not absorb a significant proportion of the energy of an impact in comparison with the energy absorbed by the energy absorbing layer3.

The liner15may be removable. This may enable the liner to be cleaned and/or may enable the provision of liners that are modified to fit a specific wearer.

Between the liner15and the energy absorbing layer3, there is provided an inner shell14formed from a relatively hard material, namely a material that is harder than the energy absorbing layer3. The inner shell14may be moulded to the energy absorbing layer3and may be made from any of the materials discussed above in connection with the formation of the outer shell2.

In the arrangement ofFIG.6, a low friction interface15′ is provided between the inner shell14and the liner15. This may be implemented by the appropriate selection of at least one of the material used to form the outer surface of the liner15or the material used to form the inner shell14. Alternatively or additionally, a low friction coating may be applied to at least one of the opposing surfaces of the inner shell14and the liner15. Alternatively or additionally, a lubricant may be applied to at least one of the opposing surfaces of the inner shell14and the liner15.

As shown, the liner15may be connected to the remainder of the helmet1by way of one or more connectors20of the present invention, discussed in further detail below. Selection of the location of the connectors20and the number of connectors20to use may depend upon the configuration of the remainder of the helmet. Accordingly, the present invention is not limited to the configuration depicted inFIG.6.

In an arrangement such as shown inFIG.6, at least one connector20may be connected to the inner shell14. Alternatively or additionally, one or more of the connectors20may be connected to another part of the remainder of the helmet1, such as the energy absorbing layer3and/or the outer shell2. The connectors20may also be connected to two or more parts of the remainder of the helmet1.

FIG.7depicts a further alternative arrangement of a helmet1using the connectors20of the present invention. As shown, the helmet1of this arrangement includes a plurality of independent sections of comfort padding16. Each section of comfort padding16may be connected to the remainder of the helmet by one or more connectors20according to the present invention.

The sections of comfort padding16may have a sliding interface provided between the sections of comfort padding16and the remainder of the helmet1. In such an arrangement, the sections of comfort padding16may provide a similar function to that of the liner15of the arrangement shown inFIG.6. The options discussed above for provision of a sliding interface between a liner and a helmet also apply to the sliding interface between the sections of comfort padding and the helmet.

It should also be appreciated that the arrangement ofFIG.7, namely the provision of a plurality of independently mounted sections of comfort padding16provided with a sliding interface between the sections of comfort padding16and the remainder of the helmet may be combined with any form of helmet, including those such as depicted inFIGS.1to5that also have a sliding interface provided between two other parts of the helmet.

Connectors20according to the present invention will now be described. For convenience, the connectors20will be described in the context of a connector for connecting a liner15to the remainder of a helmet1as depicted inFIG.6. However, it should be appreciated that the connector20of the present invention may be used for connecting any two parts of an apparatus together. Furthermore, where below the connector20is described as having a first component connected to a first part of an apparatus, such as a helmet liner15, and a second component connected to a second part of an apparatus, such as the remainder of the helmet1, it should be appreciated that, with suitable modifications, this may be reversed.

FIGS.8and9show equivalent embodiments to those ofFIGS.6and7, except that the inner shell14is applied to the liner15(inFIG.8) or comfort padding16(inFIG.9). In the case ofFIG.9, the inner shell14may only be a partial shell or a plurality of sections of shell, as compared to the substantially full shell arrangements ofFIGS.6to8. Indeed, in bothFIGS.8and9the inner shell14may also be characterised as a relatively hard coating on the liner15or comfort padding16. As forFIGS.6and7, the inner shell14is formed from a relatively hard material, namely a material that is harder than the energy absorbing layer3. For example, the material could be PTFE, ABS, PVC, PC, Nylon, PFA, EEP, PE and UHMWPE. The material may be bonded to the outer side of the liner15or comfort padding16to simplify the manufacturing process. Such bonding could be through any means, such as by adhesive or by high frequency welding.

InFIGS.8and9a low friction interface14′ is provided between the inner shell14and the energy absorbing layer3. This may be implemented by the appropriate selection of at least one of the material used to form the outer surface of the energy absorbing layer3or the material used to form the inner shell14. Alternatively or additionally, a low friction coating may be applied to at least one of the opposing surfaces of the inner shell14and the energy absorbing layer3. Alternatively or additionally, a lubricant may be applied to at least one of the opposing surfaces of the inner shell14and the energy absorbing layer3.

InFIGS.8and9, at least one connector20may be connected to the inner shell14. Alternatively or additionally, one or more of the connectors20may be connected to another part of the remainder of the liner15or comfort padding16.

FIG.10depicts, in cross-section, an embodiment of a connector20according to the present invention that may be used to connect first and second parts of an apparatus, such as a helmet. In particular it may be configured to connect a liner15to the remainder of a helmet.

In the arrangement depicted inFIG.10, the connector20includes a first sliding plate21with an anchor point22on one side of the plate21. On the other side of the first plate21to the anchor point22, a second sliding plate24is provided, having an anchor point25on the side facing away from the first plate21. Whilst the sliding plate21is shown as slightly concave inFIG.10, this is to illustrate the anchor point22and bonding to the underlying layer15. In practice, the plates21and24are both substantially flat at rest.

The sliding plates21,24may be formed from a sufficiently stiff material that they substantially retain their shape during expected use of the apparatus. In the context of a helmet, this may include normal handling of the helmet and wearing the helmet under normal conditions. It may also include conditions including an impact on the helmet for which the helmet is designed with the expectation that the impact would be survivable for the wearer of the helmet.

In the arrangement depicted inFIG.10, the first sliding plate21is provided adjacent to the surface of the second part, such as the liner15, such that the plate21may slide on the surface of the liner15(e.g. rotationally around the attachment point25).

In order to ensure that the first sliding plate21can slide relative to the second sliding plate24, a low friction interface24′ may be provided between the opposing surfaces of the two plate21,24.

In this context, a low friction interface24′ may be configured such that sliding contact is still possible even under the loading that may be expected in use. In the context of a helmet, for example, it may be desirable for sliding to be maintained in the event of an impact that this expected to be survivable for the wearer of a helmet. This may be provided, for example, by the provision of an interface between the two surfaces at which the coefficient of friction is between 0.001 and 0.3 and/or below 0.15.

In the present invention, a low friction interface24′ may be implemented by at least one of using at least one low friction material for the construction of the element forming at least one of the opposing surfaces of the plates21,24, applying a low friction coating to at least one of the opposing surfaces, applying a lubricant to at least one of the opposing surfaces, and providing an unsecured additional layer of material between the opposing surfaces that has at least one low friction surface.

The plates used in the connector of the present invention may be made from a variety of different materials. In an example, a plate may be made from polycarbonate (PC), polyvinylchloride (PVC), acrylonitrile butadiene styrene (ABS), polypropylene (PP), Nylon or another plastic. The plates may optionally have a thickness in the range of from approximately 0.2 mm to approximately 1.5 mm, for example approximately 0.7 mm thick.

The anchor point22of the first plate21is depicted inFIG.10in the form of a point at which the first plate21is attached by high frequency welding to the liner15. However, other methods of ‘permanent’ or non-releasable attachment may be used, such using an adhesive or stitching.

The anchor point25of the second plate24is depicted inFIG.10in the form of a point at which one side of a hook and loop connector26is attached (the other side being on the part to be connected, e.g. a helmet). However, other methods of ‘detachable’ attachment may be used, such as a snap-fit connection or a magnetic connector. Other forms of detachable connection may also be used.

Whilst the anchor point22of the first plate21has been discussed above for use with permanent′ attachments, and the anchor point25of the second plate2524has been discussed with ‘detachable’ attachments in the arrangement ofFIG.10, either anchor point22,25may be used for either permanent or detachable attachments. Either type of attachment may be configured such that it prevents translational movement of an anchor point22,25relative to the part being connected to. However, it may be configured such that the anchor point22,25and therefore the respective plate21,24can rotate about one or more axes of rotation relative to the part being connected to. Alternatively or additionally, the anchor points22,25may be connected to the parts to be connected by way of one or more additional components.

Both anchor points22,25are depicted as being substantially level with first and second plates21,24. However, the anchor points may include protrusions, as illustrated in WO 2017/157765, which is herein incorporated in its entirety by reference.

When viewed in plan view, the anchor points22,25may be arranged substantially at the centre of their respective plates21,24. However, the present invention is not limited to a particular configuration. When viewed in plan view, any convenient shape of the plates21,24may be used, for example substantially rectangular, substantially square, substantially circular or substantially elliptical. In the case of a shape having corners, the corners may be rounded in order to minimise the risk of the plate getting caught on another part of the connector or another component.

A cuff or collar23of deformable material is provided that at least partially covers the sides of the plates21,24incorporating the anchor points22,25. That is the cuff at least partially covers the side of the first plate21on which the first anchor point22is located and at least partially covers the side of the second plate24on which the second anchor point25is located. In other words, at least several points23aaround the perimeter of the cuff23, as illustrated inFIG.11, wrap around the outer edge of the plates21,24. In some arrangements, the entire outer edge of the plates may be covered by the cuff23, rather than just parts as shown inFIG.11.

As illustrated, the cuff23does not cover the anchor points22,25of the connector20. That is, the anchor points22,25project through apertures or gaps in the cuff23. This can be seen in the cross-sectional view ofFIG.10and in plan view for the anchor point25of the second plate inFIG.11. This avoids cuff23interfering with the connection to the surrounding first and second parts to be connected.

The cuff23is not necessarily directly attached or bonded to the plates21,24. Instead, the cuff23can be provided as a close fit around the plates21,24, such that it stays in place due to the mechanical interaction with the plates21,24. Indeed, to initially fit the plates21,24within the cuff23, it may be necessary to stretch the cuff23and/or bend the plates21,24.

The construction of the cuff23and plates21,24into the connector20can take place in different ways. In one approach, the cuff23can be provided around both plates21,24before the anchor points22,25are fixed to the parts to be connected. In another approach, the anchor points22,25can be fixed to the parts to be connected before the cuff23is provided around the plates21,24. In another approach, one plate, e.g. plate21can be attached to a first component to be connected via the anchor point22, whilst the other plate24is fitted to the cuff23. The first plate21can then also be fitted into the cuff23before the second plate24is fixed to a second component to be connected via its anchor point25.

Thereafter, as the plates21,24slide over the low friction interface (e.g. during an impact), they change their relative positions and deform the cuff23. As such, the cuff23defines a natural resting position of the plates21,24relative to the first and second parts of the surrounding apparatus to which they connect via the anchor points22,25. However, by deformation of the deformable material23during displacement of the plates21,24, for example stretching of one side of the deformable material, the plates21,24are permitted to slide. In doing so, the second part of the apparatus, such as the remainder of the helmet, which may be connected to the second anchor point25, may slide relative to the first part of the apparatus, such as the liner15, connected to the first anchor point22.

A connector20of the present invention may be configured to permit a desired relative range of movement of the anchor points22,25, and therefore the relative range of movement between the first part of the apparatus the second part of the apparatus being connected. Such configuration may be achieved by the selection of the material forming the cuff23, the thickness of the material forming the cuff23and the number of points23aaround the perimeter at which the top layer of the cuff23is connected to the bottom layer. For example, a connector20for use within a helmet may be configured to enable a relative movement between the anchor points22,25of approximately 5 mm or more in any direction within a plane parallel to the major surface of the plates21,24.

The cuff23can be formed of material that deforms substantially elastically for the required range of movement of the plate21relative to the second part. For example, the deformable material may be formed from at least one of an elasticated fabric, an elasticated cloth, an elasticated textile and an elastomeric material, e.g. a elastomeric polymeric material such as silicone/polysiloxane.

By providing an elastically deformable cuff23, after the first and second plates21,24have been displaced away from the first, resting, position, and the cuff23has been stretched, the cuff23will urge the first and second plates21,24back into the first position. In other words, the cuff23biases the first and second plates21,24towards the first position

The cuff23may be formed as a single piece, by moulding for example, or may be formed by connecting together multiple pieces, e.g. an upper layer and a lower layer, subsequently joined at the edges.