WO2020242373A1

WO2020242373A1 - Protective head device

Info

Publication number: WO2020242373A1
Application number: PCT/SG2019/050277
Authority: WO
Inventors: Sanjay AMARASINGHE
Original assignee: Amarasinghe Sanjay
Priority date: 2019-05-28
Filing date: 2019-05-28
Publication date: 2020-12-03

Abstract

Protective head device (100) for reducing an impact, including a linear impact, a rotational impact or an oblique impact. The protective head device comprises an outer shell (102) for withstanding the impact, an inner shell (104) in contact with head of a wearer; and an intermediate layer (106) arranged between the outer shell and the inner shell for damping energy of the impact. The intermediate layer comprises an outer surface fixed to the outer shell and an inner surface fixed to the inner shell. In particular, the intermediate layer can damp a unidirectional compressive energy, a rotational energy, or both. In addition, the protective head device also has an excellent aerodynamic performance and thus is applicable in cycling, motorcycling, skiing and various occupational endeavours. Moreover, the present application also provides a method of making the protective head device.

Description

PROTECTIVE HEAD DEVICE

[0001 ] The present application relates to a protective head device, and methods of making, using and testing the same.

[0002] Head injury is often a major cause of trauma-related death, associated with 90% of pre-hospital trauma-related deaths Protective head devices such as a helmet have been applied to a broad spectrum of activities to provide cranial protection against head injuries such as skull fractures and intracranial injuries Modern helmets are invariably composed of 2 layers: an outer shell - composed of lightweight, sturdy materials such as carbon fiber, Kevlar, fiber glass and polycarbonate; and a soft inner liner consisting of extended polystyrene foam (“EPS”, Styrofoam), shock-absorption material or an energy-absorbing material for absorbing compressive energy. The structural material can resist a unidirectional compressive force and technically reduce chances of sustaining skull fractures and intracranial injuries (e.g. Contusions, intracerebral haemorrhages). However, an oblique impact also has angular acceleration or rotational force at a tangential direction, in addition to the linear acceleration. The rotational force can lead to more serious injuries, such as subdural haematomas (SH), i.e. bleeding as a consequence of blood vessels rupturing and diffuse axonal injuries (DAI), i.e. nerve fibres being severed as a consequence of varying inertia and density in brain tissues. Hence, there exist a need to prevent concussion and other intracranial injuries by adopting a protective head device to mitigate these forces and reduce the resultant force on the brain.

[0003] The present application intends to provide a new and useful protective head device. The protective head device is alternatively known as personal protective equipment or helmet. The application also intends to offer methods of making, using and testing the same. Essential features of relevant inventions are provided by one or more independent claims, whilst technically advantageous features are offered by their respective dependent claims.

[0004] Alternatively speaking, the present application aims to provide a protective head device for resisting direct and/or rotational impacts by adopting suitable materials and structures because the inventor understand that neurological outcome of an impact is determined by magnitude, mechanism and nature of intracranial injuries. In principle, an impact of higher compressive energy and rotational energy would lead to a more serious neurological outcome. Many components of the protective head device are made of energy-absorbing materials, so that the protective head device can absorb locally both the compressive energy and the rotational energy within an area of the impact. Meanwhile, the protective head device has a unique structure such that the impact can be also redistributed by transmitting both the compressive energy and the rotational energy from the area of the impact to other areas of the protective head device. In addition, the protective head device of the present application also has an excellent aerodynamic performance and thus is applicable in cycling, motorcycling, skiing and other high-speed activities. It can also be applied to hazardous occupational endeavours such as industrial work. The protective head device has a plurality of advantageous properties: light in weight since many components such as an inner shell and an outer shell are made of a material of low density but high compressive strength, adapted to multidirectional impacts (i.e. Multidirectional Impact Protection System(MIPS) compliant), reusable, durable for being non-biodegradable, comfortable for wearing, well ventilated for having air vents, excellent in aerodynamics, and low costs of manufacture and maintenance. The present application also provides methods of making, using and testing the protective head device.

[0005] According to a first aspect, the present application provides a protective head device (e.g. helmet) for mitigating an external impact, including not only a linear impact (e.g. direct impact) or a rotational impact, but also an oblique impact. The protective head device comprises an outer shell for withstanding the impact, an inner shell for covering a human head; and an intermediate layer connected between the outer shell and the inner shell for damping energy of the impact. The intermediate layer is configured to reduce or dampen (i.e. retard or decrease) both unidirectional (i.e. direct or linear) and rotational (i.e. shearing) impact. The outer shell may be a thin and strong layer, sheet, case, hull or husk. The inner layer may be a thin and strong layer, sheet or cover with a soft thick inner liner that is in contact with head of a wearer.

[0006] The intermediate layer comprises an outer surface fixed to the outer shell and an inner surface fixed to the inner shell. Both unidirectional and rotational impacts are absorbed and/or redistributed by the intermediate layer. The intermediate layer is preferably comprised of a viscoelastic structural material capable of withstanding high tensile (with a relatively low Young’s modulus) and compressive forces and possessing elastic recoil properties. The variation in thickness of the circumference of the helmet is adapted to preserve aerodynamic properties but also provide additional protection in more vulnerable regions (i.e. frontal, occipital, bi-temporal, vertex).

[0007] Compared with traditional helmets, the protective head device of the present application has two distinctive advantages. Firstly, the protective head device adopts a tri-laminar structure that can resist impact energies caused by three kinds of impact, i.e. unidirectional compressive energy caused by a unidirectional compressive force, rotational energy caused by a rotational force, and both unidirectional compressive energy and rotational energy caused by the oblique force. Secondly, the protective head device can damp the impact energies by absorbing the impact energies with the intermediate layer and meanwhile by dissipating the impact energies by redistributing the impact energies from the intermediate layer to other parts of the protective head device.

[0008] The inner shell, the outer shell or both can be made of a flexible material or a combination of several flexible materials. The inner shell, the outer shell or both are made of a flexible structure or a combination of several flexible structures. For better protective effect, the outer shell may have two properties: firstly, the outer shell is light in weight such that the protective head device would not create much load on bodily elements such as neck connecting head to torso of the user; and secondly, the outer shell is strong so as to withstand various impact. Accordingly, the outer shell is made of a material that is both light in weight and high in compressive strength. In addition, the material also needs to be robust in order to resist damage incurred by a shock or penetrating injury. Suitable materials may be hard plastics or fibre-reinforced plastics, including carbon fibre (i.e. fiber), glass fibre, various aramid fibres, polycarbonate, acrylonitrile butadiene styrene (ABS) plastic, or high density polystyrene or any combination of the foregoing materials. Optionally, the outer shell is relatively thin for reducing the size of the protective head device. These include materials such as carbon fibre or Kevlar.

[0009] The inner shell optionally has a uniform thickness. Thus the inner shell may be composed of expanded polystyrene foam or equivalent material. [0010] The intermediate layer is connected between the outer shell and the inner shell, either permanently or detachably. For permanent arrangement, the intermediate layer may be moulded together with the outer shell and the inner shell. Alternatively, the intermediate layer may be adhered to the outer shell and the inner shell with strong adhesives such as cyanoacrylates (i.e. power glues or superglues) that cannot be removed without damage. For detachable arrangement, the intermediate layer is tied to the outer shell and the inner shell using spring coils which also confer stability between the inner and outer shells.

[0011 ] According to different designs of the protective head device, the intermediate layer also can be connected between the outer shell and the inner shell in various ways. For example, the intermediate layer may be partially exposed from either the outer shell, the inner shell or both. Preferably, the intermediate layer is substantially enclosed between the outer shell and the inner shell. In this way, the intermediate layer can be well kept from external contaminations such as dust or sweat since the intermediate layer is not in direct contact with an outside environment or head of the wearer.

[0012] The intermediate layer is particularly important for the protective head device since the intermediate layer can simultaneously absorb and transmit the unidirectional compressive energy and/or the rotational energy. For each case, a working principle would be clarified below. For easy explanation, the intermediate layer is imaginarily divided into a front portion with a first thickness, a rear portion with a second thickness, a left portion with a third thickness and a right portion with a fourth thickness. The rear portion is distal to or opposite to the front portion, while the left portion and the right portion are between the front portion and the rear portion.

[0013] The intermediate layer damps the unidirectional compressive energy by absorbing and transmitting the unidirectional compressive energy. In this way, the unidirectional compressive energy is not only absorbed locally, but also redistributed across the entire intermediate layer. For example, the unidirectional compressive force is applied to a center of the front portion, the front portion absorbs a fraction of the unidirectional compressive energy by contracting the first thickness. Meanwhile, another fraction of the unidirectional compressive energy is transmitted to the rear portion, the left portion and the right portion by expanding the second thickness, the third thickness and the fourth thickness respectively. The expansion of the rear portion is greater than the left portion and the right portion. It is reasonably understood that the contraction and expansion occur gradually within the intermediate layer. In other words, the intermediate layer deforms symmetrically to an imaginary axis from the center of the front portion to a center of the rear portion. In addition, the unidirectional compressive energy may also be transmitted from the intermediate layer to the inner shell as well.

[0014] The intermediate layer may dampen or reduce the rotational energy partially by absorbing and transmitting the rotational energy. In this way, the rotational energy is not only absorbed locally, but also redistributed across the intermediate layer. For example, the rotational force is applied to the center of the front portion or the rear portion, the front portion and the rear portion absorb a fraction of the rotational energy by expanding the first thickness and the second thickness respectively. Meanwhile, another fraction of the rotational energy is transmitted to the left portion and the right portion by contracting the third thickness and the fourth thickness respectively. It is reasonably understood that the contraction and expansion occur gradually within the intermediate layer. In other words, the intermediate layer deforms symmetrically to an imaginary axis from the center of the front portion to a center of the rear portion. In addition, the rotational energy may be transmitted from the intermediate layer to the inner shell as well.

[0015] The intermediate layer may structurally comprise a plurality of matrix sub-units (also known as columns) for partially absorbing and diverting (e.g. distributing) the unidirectional impact, rotational impact or both to another place of the inner shell. The plurality of matrix sub-unitshave spaces or gaps between the matrix sub-units so that ventilation air can pass through the spaces or gaps. In other words, the plurality of matrix sub-units comprises discrete components that are uniformly separated across the intermediate layer interface between the inner and outer shells. The columns are used to depicts the matrix subunits distributed separately from each other. Collectively, the matrix sub-units give visual impression that the matrix sub-units form a continuous stream or array.

[0016] One or more of the plurality of matrix sub-units (i.e. columns) can be substantially slanted (i.e. not perpendicular) against the inner shell, the outer shell or both at contact place of the one or more columns. The slanted orientation of the columns is operable for transmitting the impact energy from the columns directly under the impact to other columns located out of the impact area. In this way, the impact energy is more quickly and effectively damped by transmittance, in addition to local absorption.

[0017] The plurality of columns (i.e. matrix sub-units) optionally comprises multiple columns that are preferably arranged in parallel fashion, at a fixed angled orientation, relative to the inner and outer shells, all along the circumference of the helmet: collectively, the multiple columns enable an impact to be absorbed in any direction.

[0018] The multiple columns (i.e. matrix sub-units) may be spaced apart from each other. The multiple columns may comprise a same material of specific dimensions. For example, a column at a front portion of the protective head device is a thicker than another column at a back portion of the protective head device. As a result, the protective head device is uniquely designed for a specific purpose.

[0019] One or more of the plurality of columns (i.e. matrix sub-units) can be elastic, flexible, deformable, resilient, compressible, or have properties of a combination of any of these. For example, to fulfil a function of expansion and contraction, the columns of the intermediate layer are preferably made of one or more flexible and energy absorbing materials. The materials can be natural, synthetic or a combination thereof. The natural materials include collagen, and natural rubber or the alike. While the synthetic materials include viscoelastic polymers - e.g. Sorbothane, synthetic rubbers (eg. Silicon rubber, neoprene, butyl rubber, polyurethane), Akton polymer; gels (including hydrogels) and foams (polyethylene, polypropylene and expanded polystyrene foam) and equivalent materials. The intermediate layer can also be made of any combination of the foregoing natural materials, the foregoing synthetic materials or both. Preferably, the material employed is a viscoelastic material with optimal compressive or expansive properties, including elastic recoil.

[0020] One or more of the plurality of columns (i.e. matrix sub-units) can have uniform cross sectional areas throughout their lengths respectively.

[0021 ] Spring coils are optionally placed interspersed throughout the intermediate layer for stabilising the intermediate interface from excessive rarefaction/expansion and translation, thereby providing better integration between the inner and outer shells. [0022] The protective head device may further comprise a liner for conforming to a contour of the head of the wearer. As a result, the liner provides comfort and appropriate fit for the wearer. Therefore, the liner is made of a flexible material. Meanwhile, the linear is made of an energy absorbing material for further reducing the unidirectional impressive energy, such as compressible and impact attenuating polymer material. The compressible and impact attenuating polymer material can be expanded polystyrene (EPS), expanded polypropylene (EPP), expanded polyurethane (EPU), or equivalent material.

[0023] The liner is sometimes removable, reconfigurable, or exchangeable from the protective head device. The liner is removable such that the liner is detachably tied to the inner shell with one or more fixation members such as snap fasteners. In lieu of snap fasteners, alternate means includes but not limited to screws, buttons, detent arrangements, removable adhesive strips, hook-and-loop strips and the alike. The liner is reconfigurable for providing a custom fit for a wide range of wearers having different head sizes and/or shapes. The liner is exchangeable such that the various types of liners can be attached to a specific protective head device for different purposes. For example, a protective head device in a construction site is adopted with a thick liner for absorbing more potential impact energies. While another protective head device in a sports activity such as cycling is used with an air permissible line for air exchange.

[0024] The protective head device can advantageously comprise a retention system for securing the protective head device to the wearer's head. For example, the retention system may comprise one or more straps that could be twined around the chin of the wearer, so that the protective head device is secured to the head of the wearer.

[0025] For fulfilling the function of damping both the unidirectional compressive energy and the rotational energy, the intermediate layer preferably has a distinctive and advantageous structure comprising a plurality of sub-units. The sub-units are discrete component with space interspersed between two adjacent sub-units. Each of the sub units has an outer surface fixed to the outer shell and an inner surface fixed to the inner shell. In this way, the intermediate layer is either permanently or temporally fixed between the outer shell and the inner shell and thus the intermediate layer is immobile in the protective head device. [0026] Under a neutral state when the impact is not applied, the sub-units may have a same dimension and orientation. In a cross-sectional view perpendicular to a height direction, each of the sub-units may have a shape of any geometric figure such as triangle square or circle. Preferably, the columns are cylindrical in shape. The optimal dimensions for these columns are varied according to specific requirements.

[0027] Specifically, the discrete sub-units within the intermediate layer are optionally oriented in a diagonally oriented configuration and a complimentary diagonally oriented configuration, to form a matrix configuration o. In the diagonally oriented configuration, all the sub-units are inclined in a same way such as from right to left. In the complimentary diagonally oriented configuration, all the sub-units are inclined in a same but complimentary way such as from left to right. In the matrix configuration, a first amount of sub-units is inclined in a diagonally oriented configuration; while a second amount of sub-units is inclined in a complimentary diagonally oriented configuration. The first amount is equal to the second amount. In other words, the intermediate layer comprises a plurality of matrix units in the matrix configuration; and each of the matrix unit comprises a first sub-unit in a diagonally oriented configuration and a second sub unit in a complimentary diagonally oriented configuration. The first sub-unit and the second sub-unit may be connected together at the intersection of each sub-unit column.

[0028] The matrix configuration is particularly effective for not only effectively absorbing the unidirectional compressive energy and the rotational energy but also redistributing the energies from the area under the impact or impact area (e.g. frontal area, occipital area, bi-temporal area, and vertex area) to other areas of the protective head device away from the impact area.

[0029] Under the unidirectional compressive force, the space interspersed between two adjacent sub-units of the matrix configuration permits the two adjacent sub-units to radially expand. While under the rotational force, the matrix configuration also enables each diagonally orientated sub-unit expand. The protective head device of the matrix configuration is thus compliant with the multi-directional Impaction Protection System (MIPS) International Standard for reducing rotational forces on brain. In a macro view, the intermediate layer is made of a plurality of the sub-units of the matrix configuration for fulfilling the properties of contraction or rarefaction under various conditions. [0030] The plurality of columns can be distributed over one or more portions of the protective head device at either inner shell, the outer shell or both uniformly or evenly (known as matrix formation). For example, the plurality of columns is distributed over the inner shell non-uniformly. The columns are adopted as the sub-units in the diagonal configuration and complimentary diagonal configuration, which combine to form a matrix configuration. Optionally, the columns as the sub-units have a uniform distribution in the intermediate layer for rendering a homogenous mechanical property to the intermediate layer. As a result, the protective head device can resist impact energies from all directions effectively. It is understood that the distribution of the sub units in the intermediate layer can be adjusted or altered according to specific requirements.

[0031 ] The sub-units may absorb the unidirectional compressive energy by a first conformational change. For example, when a unidirectional compressive force is applied to the front portion of the intermediate layer, the sub-units within the front portion absorb the unidirectional compressive energy by undergoing a first conformational change. The first conformational change comprises contracting the sub units in height and meanwhile expanding the sub-units in width, leading to an exaggerated orientation of the diagonally oriented configuration, the complimentary configuration, the matrix configuration or any combination thereof. As a result, the front portion become contracted as mentioned above, and the first thickness becomes thinner accordingly. In a macro view, the first conformational change results in an intensification of local sub-units within the front portion.

[0032] The sub-units can absorb the rotational energy by a second conformational change. For example, when the rotational force is applied to the front portion the intermediate layer, the sub-units within the front portion absorb the rotational energy by undergoing a second conformational change. For the diagonally oriented configuration or the complimentary configuration, the second conformational change comprises expanding the sub-units in height and meanwhile contracting the sub-units in width accordingly, leading to an exaggerated orientation. For the matrix configuration, the second conformational change comprises a similar process for the sub-units in the diagonally oriented configuration and an opposite process for the sub-units in the complimentary diagonally oriented configuration. In the opposite process, the sub-units contract in height and meanwhile expand in width accordingly, leading to a depressed orientation. As a result, the front portion of the intermediate layer becomes contracted as mentioned above, and the first thickness becomes thicker accordingly. In a macro view, the second conformational change results in a rarefaction of sub-units within the front portion of the intermediate layer.

[0033] The sub-units under the impact may transmit the energy of impact energy to other sub-units away from the impact. The energy of the impact may comprise unidirectional compressive energy, rotational energy, or both. In case that the unidirectional compressive force is applied to the front portion, the unidirectional compressive energy is gradually transmitted to the sub-units of the rear portion, the left portion and the right portion. In the rear portion, the sub-units expand in height and meanwhile contract in width, making the rear portion expanded as mentioned above, and the second thickness thicker accordingly. In a macro view, a rarefaction of sub units occurs within the rear portion. Similarly, rarefactions also happen in the left portion and the right portion, but to a less degree. It is reasonably understood that the contraction and expansion occur gradually within the intermediate layer.

[0034] In case that the rotational force is applied to the front portion, the rotational energy is gradually transmitted to the sub-units of the rear portion, the left portion and the right portion. Similar to the front portion, the sub-units in the rear portion also undergo a second conformational change, i.e. the sub-units expand in height and meanwhile contract in width, making the rear portion of the intermediate layer expanded and the second thickness thicker accordingly. In a macro view, a rarefaction of sub units occurs within the rear portion. In contrast, the sub-units in the left portion and the right portion undergo an opposite process, i.e. the sub-units contact in height and expand in width, making the left portion and the right portion of the intermediate layer contracted and the third thickness and the fourth thickness thinner accordingly. In a macro view, intensifications of sub-units occur within the left portion and the right portion. It is reasonably understood that the contraction and expansion occur gradually within the intermediate layer.

[0035] One or more of the plurality of columns may comprise a bundle of elastic or flexible fibres. Each fibre has two opposite ends connected to the inner shell and the outer shell respectively. The elastic fibres are provided in order to form an elastic recoil mechanism. A single sub-unit may comprise a plurality of elastic fibres combined in a parallel configuration. Each of the elastic fibres can undergo multiple cycles of compression and expansion, and therefore has an elastic recoil property for forming an elastic recoil mechanism to the sub-unit as a whole. The elastic fibre can be of any shape and length not exceeding the length of the sub-unit. Preferably, the elastic fibre has a cylindrical shape.

[0036] The sub-units under the impact can transmit the energy of the impact to the outer shell and the inner shell by the elastic recoil mechanism. As discussed above, the outer surface and an inner surface of each sub-unit are fixed to the outer shell and the inner shell, respectively. When the elastic fibres of the sub-unit are expanded under force, the expansion energy within the sub-unit is transmitted to the outer shell and the inner shell. In comparison, when the elastic fibres of the sub-unit are compressed under force, the compression energy within the sub-unit is also transmitted to the outer shell and the inner shell. As a result, the impact energy consisting of expansion energy and compression energy is transmitted from the sub-units of the intermediate layer to the outer shell and the inner shell.

[0037] The bundle of fibres are optionally made of helical polymer. The helical polymer has a helicity of chain structure, i.e. the chain structure spirals along a chain axis like in a spring. The helical polymer can be natural polymers such as collagen or some kinds of polypepides. The helical structure can expand (under tensile force) or contract (under compressive force or when in returns to its neutral state during elastic recoil) in alignment with the axis of the applied force.

[0038] The plurality of columns is aligned for providing at least one ventilation channel (also known as air vent). As discussed above, the sub-units are discrete components with space interspersed between two adjacent sub-units. On one hand, the space leaves necessary room for the adjacent sub-units to expand under the expansion force; on the other hand, the space also acts as an air vent or air channel of the intermediate layer for circulating air through the intermediate layer. Under the neutral state when no impact force is applied, the air vent preferably has a uniform distribution in the intermediate layer. In this way, the wearer feels more comfortable since air can be exchanged between the outer shell and inter shell through the intermediate layer. [0039] The air vent can decrease in its opening size when the two adjacent sub-units expand under the impact. In an extreme case when the impact force is extremely strong, the air vent is obliterated or closed when the two adjacent sub-units are in direct contact. As a result, the intermediate layer becomes a continuous element such that the protective head device can resist even more stronger impact.

[0040] The intermediate layer may comprise a plurality of air vents in the intermediate layer. Air enters as an incoming airflow into the inner shell from the outer shell via a first group of the air vents; meanwhile, air also exists as an outgoing airflow from the inner shell to the outer shell via a second group of the air vents. Under the neutral state when no impact force is applied, the first group of the air vents and the second group of the air vents are preferably arranged in a symmetrical manner.

[0041 ] The outer shell and the inner shell are optionally permeable to air flow. Air exchange is desired between an ambient environment and the head of the wearer. In this way, the wearer feels more comfortable since sweats from the head of the wearer can be dissipated out of the protective head device.

[0042] One or both of the outer shell and inner shell optionally have perforations for air ventilation. These perforations within the outer shell are also known as air holes since the perforations are exposed to the ambient environment. The air hole has a first opening on a bottom surface, a second opening on a top surface opposite to the bottom surface and a body between the bottom surface and the top surface. The air hole may be connected to the air vent of the intermediate layer via the first opening and also exposed outside of the protective head device. The perforations within the inner shell may be also connected to the air vent of the intermediate layer. In this way, air exchange can be more efficiently and easily conducted through the outer shell via the second opening, the body, the first opening of the air hole, then through the intermediate layer via the air vent, and finally through the inner layer via the perforation. The permeability/connectivity of airflow between the air holes and air vents enable air to flow in or egress during states of columnar compression, expansion or rotation.

[0043] The outer shell optionally has shelters or miniature roofs for covering the perforations (also known as air holes) for preventing rainwater from entry. The second opening is exposed to ambient environment and thus subjected to various environmental factors or even hazards, such as rainwater, snow, dust, chemical contaminates, microorganism, and other toxic substances. Rainfall is a more common environment factor in tropical countries such as Singapore. Therefore, rainwater is prevented from going into the protective head device by covering the perforations by the shelters. The shelters can be either temporarily or permanently installed at the outer shell. When not in use, the shelters are optionally removed or turned away from the protective head device. Each of the shelters may be small in size for just covering the second opening of the air hole. Alternatively, the shelter may be a single part that is larger enough for covering all the air vents. In addition, the outer shell optionally comprises grooves for guiding flow of rainwater away to an edge of the outer shell. The rainwater is then drained away from the protective head device and not accumulated around the shelters or the air holes. The groves can be of any shape, depth and design that are suitable for rainwater drainage. Meanwhile, the groves do not interface with airflow through the outer shell, i.e. the groves are not overlapped with the second opening of any air hole in the outer shell.

[0044] Optionally, the outer shell comprises multiple air channels for forming laminar airflows for reducing airflow resistance, particularly when the wearer travels at a high speed. The air channels may be made across the outer shell and distributed preferably in a symmetrical manner. The air channel may comprise an inlet for an incoming airflow into the air channel and an outlet for an outgoing airflow out of the air channel. The inlet and the outlet can be located at any position of the outer shell. For example, the inlet is located at a front side; while the outlet is located at a back side opposite to the inlet.

[0045] The air vent is preferably connected to one or more of the multiple air channels and the inner shell. In this design, the laminar air flowing in the air channels may enter into the air vent and then reach the inner shell of the protective layer. As a result, the air exchange is facilitated by flowing the air from the ambient environment into the air channels of the outer shell, through the intermedia layer via the air vent, through the air permeable inner shell, and finally to the head of the wearer.

[0046] One or more sensors (e.g. force sensor, speed sensor, a camera) may be installed in the protective head device for monitoring physical parameters of the wearer. For example, when the protective head device is in use, the sensors keep watch and record potential head impacts such as during a serious fall. When the impact is severe, the protective head device may checkout out for concussion symptoms via the sensors. More advantageously, the protective head device may have an embedded Global Positioning System (GPS) auto notification feature that locates an unresponsive wearer remotely from coordinates of the fall. Alternatively, the sensors communicate with a personal communication device such as a smartphone that automatically calls for help if the wearer is unconscious after the fall. In addition, when the protective head device is used in sports such as racing, various physical parameters of the wearer such as heart beat, body temperature, and blood pressure can be transmitted by an integrated communication unit or the personal communication device to a data center for deep analysis.

[0047] The protective head device may comprise other additional components, such as a headset, an earpiece, a light indicator, a ventilation fan, a radio transmitter, a radio receiver, a laser pointer, an alarm, a recorder (e.g. black box), an illuminator (e.g. torch light), a head strap, a rain cover, a wind shield, a neck supporter, a neck protector, a face guard, a hairclip, a cooling pad, or a combination of any of these. These additional components are preferably detachably installed on the protective head device such that the additional components can be detached when not in use. Particularly, the protective head device optionally comprises a warning system such as a warning light that is communicatively connected with the sensors and further with integrated communication unit or the personal communication device. When any of the physical parameters of the wearer is abnormal, the warning system instantly notify the wearer such that the wearer can take emergency actions accordingly without delay.

[0048] One or more components of the protective head device may be replicable, including but not limited to the outer shell, the intermediate layer with columns, the inner shell and the liner. The components are optionally detachable or exchangeable without using a tool, (i.e. by human hands only). For example, one or more of the plurality of columns can be removed and replaced if a user of the protective head device wishes to have a soft head protective gear (i.e. less robust or smaller Hooke’s constant). Alternatively, the component such as the inner layer can be removed and replaced as a whole. As a result, the components can be easily replaced with a replicator when damaged or not suitable anymore. In this way, the protective head device can be suitable for various wearers having different head sizes. The helmet can also be manufactured in different sizes, suited to the wearer. [0049] According to a second aspect, the present application provides a method of making the protective head device. The method comprises a step of providing an outer shell for withstanding an impact; a step of providing an inner shell for covering a wearer’s head; a step of providing an intermediate layer; and a step of providing the intermediate layer connected between the outer shell and the inner shell for damping, absorbing, reducing the impact; and arranging (such as configuring, organising or making) structure of the intermediate layer to reduce or dampen both unidirectional (i.e. direct) and rotational (i.e. shearing) impacts. The intermediate layer comprises an outer surface and an inner surface such that the outer surface is in contact with the outer shell and the inner surface is in contact with the inner.

[0050] Optionally, the method of making the protective head device comprises a step of fixing the intermediate layer to the outer shell and the inner shell. In detail, the outer surface of the intermediate layer is fixed to the outer shell either permanently or detachably; and the inner surface of the intermediate layer is fixed to the inner shell, either permanently or detachably. For permanent fixation, the intermediate layer may be adhered to the outer shell and the inner shell with strong adhesives such as cyanoacrylates (i.e. power glues or superglues) that cannot be removed without damage. For detachable fixation, the intermediate layer is tied to the outer shell and the inner shell with one or more fixation members such as snap fasteners. In lieu of snap fasteners, alternate means includes but not limited to screws, buttons, detent arrangements, removable adhesive strips, hook-and-loop strips and the alike. Alternatively, the intermediate layer is moulded, either in-moulded or co-moulded with the outer shell and the inner shell as a means of permanent fixation. The moulding method is particularly suitable for making the protective head device for motor sports including street and off-road motorcycling, and human powered or gravity sports such as bicycling and skiing.

[0051 ] Optionally, the method of making the protective head device also comprises a step of providing a liner to the inner shell for conforming to a contour of a head of a wearer. The liner can be fixed to the inner shell either permanently or detachably. For permanent fixation, the liner may be adhered to the inner shell with strong adhesives such as cyanoacrylates (i.e. power glues or superglues) that cannot be removed without damage. For detachable fixation, the liner is tied to the inner shell with one or more fixation members such as snap fasteners. In lieu of snap fasteners, alternate means includes but not limited to screws, buttons, detent arrangements, removable adhesive strips, hook-and-loop strips and the alike.

[0052] The step of arranging (such as configuring, organising or making) structure of the intermediate layer optionally comprises a step of providing a plurality of columns as the sub-units for diverting the impact. The columns (i.e. sub-units) are discrete components with space interspersed between two adjacent sub-units. The method may further comprise a step of uniformly distributing the plurality of columns over one or more portions of the protective head device or the protective head device as a whole. As a result, the protective head device has a homogeneous mechanical property such that the protective head device can resist the impact from any direction.

[0053] The step of providing a plurality of columns can comprise a step of causing one or more of the plurality of columns to be slanted against the inner shell, the outer shell or both. The slanted orientation of the columns has an advantage of transmitting the impact energy from the columns directly under the impact to other columns located out of the impact area. The step of causing one or more of the plurality of columns to be slanted optionally further comprises step of making multiple columns at an angle with respect to each other. The above step may be conducted by randomly orienting the columns such that the multiple columns are adapted for damping the impact no matter which direction the impact comes from.

[0054] Preferably, the method of making the protective head device further comprises a step of arranging the slanted columns (i.e. sub-units) in a diagonally oriented configuration, a complimentary diagonally oriented configuration, to form a matrix configuration. As a result, the intermediate layer can damp the impact energy by absorbing a fraction of the impact energy with the sub-units in the impact area and also by redistributing the other fraction of the impact energy to the other sub-units outside the impact area.

[0055] The method optionally comprises a step of bundling fibres to make one or more of the plurality of columns by fibres. The method of making the protective head device preferably comprises a step of providing a plurality of elastic fibres; and a following step of bundling or assembling the plurality of elastic fibres into one or more columns (i.e. sub-units) for forming an elastic recoil mechanism. The elastomer which adopts a helical polymeric configuration capable of expanding under tension, contracting under compression and undergoing elastic recoil.

[0056] The step of making multiple columns at an angle may comprise spacing or separating the multiple columns apart from each other. The space or gap between the columns is formed as air vents in the intermediate layer. Each of the plurality of air vents is interspersed between two adjacent columns (i.e. sub-units) of the intermediate layer for circulating air through the intermediate layer. The method may further comprise a step of aligning the plurality of columns for providing one or more ventilation channels between the plurality of columns. If the columns (i.e. sub-units) are uniformly distributed in the intermediate layer, the air channels in the intermediate layer (i.e. air vents) between two adjacent sub-units has an identical size accordingly. As a result, the protective head device has a homogeneous property of air ventilation, in addition to the homogeneous mechanical property to impact.

[0057] The method of making the protective head device may further comprise a step of making a plurality of air holes through the outer shell. Each of the plurality of air holes has a first opening connected to an air vent of the intermediate layer and a second opening exposed outside of the protective head device. The method may further comprise a step of making multiple air channels in the outer shell for forming laminar airflows. The method preferably comprises a step of making an inlet for an incoming airflow into one or more of the multiple air channels; and a step of making an outlet for an outgoing airflow out of the at least one of the multiple air channels. The method optionally comprises a step of making a first opening of the air vent connected to one or more of the multiple air channels; and a step of making a second opening of the air vent connected to the inner shell. As a result, air exchange can be facilitated between the ambient environment and the head of the wearer through the protective head device.

[0058] The method optionally comprises a step of sheltering one or more portions of the outer shell particularly at the air holes or perforations for preventing rainwater from entry into the protective head device. The step of sheltering is performed by installing shelters either temporarily or permanently at the outer shell. When not in use, the shelters are optionally removed or turned away from the protective head device. For permanent installation, the shelters may be adhered to the outer shell with strong and water-proof adhesives such as cyanoacrylates (i.e. power glues or superglues) that cannot be removed without damage. For detachable installation, the shelters may be tied to the outer shell and the inner shell with one or more fixation members such as snap fasteners. In lieu of snap fasteners, alternate means includes but not limited to screws, buttons, detent arrangements, removable adhesive strips, hook-and-loop strips and the alike.

[0059] The method may further comprise a step of providing one or more releasable catches for detaching or exchanging a part of the protective head device. The step is preferably conducted without using a tool (i.e. by human hands only). The releasable catches may be devices for securing the part onto the protective head device. For example, in case of the detachable fixation of the liner, the method may further comprise a step of removing or replacing the linear from the inner shell. The step is conducted by untying the fixation members such as snap fasteners, screws, buttons, detent arrangements, removable adhesive strips, hook-and-loop strips and the alike.

[0060] The method may further comprise a step of installing one or more sensors (e.g. force sensor, a camera) on the protective head device for monitoring physical parameters of the wearer, especially when protective head device the in use. The step of installing optionally comprises a step of keeping watch and recording by the sensors potential head impacts such as during a serious fall. When the impact is severe, the method optionally comprises a step of checking out for concussion symptoms via the sensors. In the case that the protective head device has an embedded Global Positioning System (GPS) auto notification feature, the method optionally comprises a step of locating an unresponsive wearer remotely from coordinates of the fall. Alternatively, the method optionally comprises a step of communicatively connecting the sensors with a personal communication device such as a smartphone that automatically calls for help if the wearer is unconscious after the fall. In addition, when the protective head device is used in sports such as racing, the method optionally comprises a step of transmitting various physical parameters of the wearer such as heart beat, body temperature, and blood pressure to a data center by an integrated communication unit or the personal communication device. Thus the method optionally comprises a step of analyzing the physical parameters at the data center in a form of a local computer or a remote server. [0061 ] According a third aspect, the present application provides a method of using the protective head device. If the protective head device is made of discrete components, the method comprises a step of wearing an inner shell; a step of installing an intermediate layer on the inner shell; and a step of installing an outer shell on the intermediate layer. The method of using the protective head device may further comprise a step of wearing a liner before wearing the inner shell; and a following step of installing the inner shell on the liner.

[0062] If the protective head device is moulded as a unitary device, the method of using the protective head device comprises a single step of wearing the moulded protective head device. The method may further comprise a step of wearing the liner, and a following step of wearing the protective head device. Alternatively, the method may further comprise a step of fixing the liner to the protective head device and a following step of wearing the liner and the protective head device as a whole.

[0063] For different purposes, the testing is conducted according to various standardised testing criteria, such as EN 1078 standard in European for pedal cyclists and users of skateboards and roller skates; Consumer Product Safety Commission (CPSC) standard in the United States for bicyclists; Snell Memorial Foundation 1990 Standard for use in bicycling (Snell B90), 1995 Standard for protective headgear for use with bicycles (Snell B95) and standard for protective headgear for use in non -motorized sports (Snell N94); and other international standards.

[0064] According a fourth aspect, the present application provides an apparatus for testing the protective head device in lab. The apparatus comprises a protective head device as described above, comprising an outer shell, an inner shell and an intermediate layer arranged between the outer shell and the inner shell. The apparatus also comprises a first pressure sensor mounted on the outer shell; a second pressure sensor mounted the inner shell; and an equipment for measuring a thickness of the intermediate layer.

[0065] According a fifth aspect, the present application provides a method of testing the shock absorption capabilities of the material defining the intermediate layer of the device The method also comprises a step of providing a first pressure sensor, wherein a first surface of the first pressure is mounted on the outer shell; a step of providing a second pressure sensor, wherein a first surface of the second pressure sensor is mounted on the inner shell; a step of attaching a second surface of the second pressure sensor on a wall; a step of applying an external force on a second surface of the first pressure; a step of calculating a pressure difference of the first pressure sensor and the second pressure sensor. Additional testing can be conducted to determine the optimal thickness of material by correlating material thickness with pressure difference (i.e. shock absorption ability).

[0066] After being tested in the lab, the protective head device is finally evaluated in field with a variety of methods of assessment, including concussion rates for American footballers, annual hospital rates of diagnosed minor, moderate and severe brain injuries, trauma-related deaths attributed to head trauma. The assessment methods are divided into several types of intracranial injuries: extradural, subdural and intracerebral haematoma, skull fractures, diffuse axonal injury, and etc. for determining performance of the protective head device of the present application. Other indices to assess neurological outcome after traumatic brain injury can also be utilised, e.g. Glasgow Outcome Score, disability index, etc.

[0067] The accompanying figures (i.e. Figs., drawings, pictures or diagrams) illustrate embodiments and serve to explain principles of the disclosed embodiments. It is to be understood, however, that these figures are presented for purposes of illustration only, and not for defining limits of relevant applications.

[0068] Fig. 1 illustrates a cross-sectional view of a protective head device in a neutral state;

[0069] Fig. 2 illustrates a cross-sectional view of a protective head device in a unidirectional compressive state;

[0070] Fig. 3 illustrates a cross-sectional view of a protective head device in a rotational state;

[0071 ] Fig. 4 illustrates a cross-sectional view of two sub-units in the diagonally oriented configuration on a plane in a neutral state;

[0072] Fig. 5 illustrates a cross-sectional view of two sub-units in the complimentary diagonally oriented configuration on a plane in a neutral state;

[0073] Fig.6 illustrates a cross-sectional view of two matrix units on a plane in a neutral state; [0074] Fig.7 illustrates a cross-sectional view of two sub-units in the diagonally oriented configuration on a plane for absorbing a unidirectional compressive energy;

[0075] Fig. 8 illustrates a cross-sectional view of two sub-units in the complimentary diagonally oriented configuration on a plane for absorbing a unidirectional compressive energy;

[0076] Fig.9 illustrates a cross-sectional view of two matrix units on a plane for absorbing a unidirectional compressive energy;

[0077] Fig.10 illustrates a 3D perspective view of a matrix unit on a plane in a neutral state;

[0078] Fig.1 1 illustrates a 3D perspective view of a matrix unit on a plane under a unidirectional compressive force;

[0079] Fig.12 illustrates a cross-sectional view of two sub-units in the diagonally oriented configuration on a curve in a neutral state;

[0080] Fig.13 illustrates a cross-sectional view of two sub-units in the complementary diagonally oriented configuration on a curve in a neutral state;

[0081 ] Fig.14 illustrates a cross-sectional view of two matrix units on a curve in a neutral state;

[0082] Fig.15 illustrates a cross-sectional view of four sub-units in the diagonally oriented configuration on a curve for absorbing a rotational energy;

[0083] Fig.16 illustrates a cross-sectional view of four sub-units in the complementary diagonally oriented configuration on a curve for absorbing a rotational energy;

[0084] Fig.17 illustrates a cross-sectional view of four matrix units on a curve for absorbing a rotational energy;

[0085] Fig.18 illustrates a cross-sectional view of the intermediate layer on a curve for transmitting a unidirectional compressive force;

[0086] Fig.19 illustrates a cross-sectional view of the intermediate layer on a curve for transmitting a rotational force;

[0087] Fig.20 illustrates a perspective view of stacked elastic fibres and helical polymers in a neutral state;

[0088] Fig.21 illustrates a single helical polymer under an expanding force or under a compressive force;

[0089] Fig.22 illustrates a cross-sectional view of spring coils dispersed in the intermediate layer; [0090] Fig.23 illustrates a 3D perspective view of the protective head device with spring coils;

[0091 ] Fig.24 illustrates a cross-sectional view of air ventilation for half of the protective head device;

[0092] Fig.25 illustrates a cross-sectional view of aerial ventilation for the protective head device;

[0093] Fig.26 illustrates a cross-sectional view of air ventilation in the neutral state and under the unidirectional compressive force;

[0094] Fig.27 illustrates a cross-sectional view and an overhead view of air ventilation;

[0095] Fig.28 illustrates a cross-sectional forward-facing view of air holes in the outer shell;

[0096] Fig.29 illustrates a cross-sectional view of air channels in the outer shell;

[0097] Fig.30 illustrates a perspective view of air channels in the outer shell from top of the protective head device;

[0098] Fig.31 illustrates a 3D diagrammatic view of laminar airflow across the protective head device;

[0099] Fig.32 illustrates a method of making the protective head device;

[0100] Fig.33 illustrates a method of using the protective head device;

[0101 ] Fig.34 illustrates an apparatus for testing the protective head device; and

[0102] Fig.35 illustrates result analysis of the testing in Fig.34.

[0103] Exemplary, non-limiting embodiments of relevant inventions will now be described with references to the above-mentioned figures.

[0104] Fig. 1 illustrates a cross-sectional view of a protective head device 100 in a neutral state. The protective head device 100 comprises an outer shell 102 for withstanding an impact, an inner shell 104 in contact with head of a wearer; and an intermediate layer 106 arranged between the outer shell 102 and the inner shell 104 for damping energy of the impact. The intermediate layer 106 further comprises a plurality of matrix units 108, and each matrix unit 108 comprise a first sub-unit 1 10 (drawn in solid line) in a diagonally oriented configuration and a second sub-unit 1 12 (drawn in dash line) in a complimentary diagonally oriented configuration. Particularly, the first sub-unit 1 10 and the second sub-unit 1 12 not connected together. Fig. 1 shows that the protective head device 100 is in a neutral state when no impact is applied and thus the intermediate layer 106 has a same thickness across the entire intermedia layer 106. Each of the first sub-units 1 10 or the second sub-units 1 12 has an outer surface 1 14 fixed to the outer shell 102 and an inner surface 1 16 fixed to the inner shell 104. In this way, the intermediate layer 106 is either permanently or temporally fixed between the outer shell 102 and the inner shell 104 and thus the intermediate layer 106 is flexible within the confines of the inner and outer shell in the protective head device 100. In the intermediate layer 106, the matrix units 108 are discrete in that two adjacent matrix units 108 are separated by space 118. Each of the sub-units 1 10, 1 12 can have any shape such as a cylindrical shape 120. The matrix units 108 can be either uniformly distributed or distributed according to specific requirements. The sub-units 1 10, 1 12 are made of an energy-absorbing material, either natural or synthetic for locally absorbing the unidirectional compressive energy or the rotational energy.

[0105] The intermediate layer 106 can damp the energy of the impact, which may comprise a unidirectional compressive energy caused by a unidirectional compressive force 138 in a linear direction, a rotational energy caused by a rotational force 144 incurred in a tangential direction, or an oblique energy caused by an oblique force. The oblique energy comprises both a unidirectional compressive energy and a rotational energy since the oblique force can be decomposed into a unidirectional compressive force 138 in a linear direction and a rotational force 144 in a tangential direction. Therefore, the protective head device 100 effectively resists a unidirectional compressive force, a rotational force 144 or more commonly an oblique force.

[0106] Fig. 2 illustrates a cross-sectional view of a protective head device 100 in a unidirectional compressive state. The intermediate layer 106 is imaginarily divided into a front portion 122 with a first thickness 124 and a first diameter 125, a rear portion 126 with a second thickness 128 and a second diameter 129, a left portion 130 with a third thickness 132 and a third diameter 133 and a right portion 134 with a fourth thickness 136 and a fourth diameter 137. A unidirectional compressive force 138 is applied on the protective head device 100 and impacts directly to a center of the front portion 122 of the intermediate layer 106. The intermediate layer 106 deforms symmetrically to an imaginary axis 140 from the center of the front portion 122 to a center of the rear portion 126. Accordingly, Fig.2 also shows that the contraction and expansion occur gradually within the intermediate layer 106. [0107] Due to the unique structure of the matrix units 108, the unidirectional compressive energy is damped by the intermediate layer 106 in several ways. Firstly, the matrix units 108 are made of an energy-absorbing material. The matrix units 108 within the front portion 122 thus locally absorb a first fraction of the unidirectional compressive energy by compressing the matrix units 108. In particular, a first matrix unit 123 at the center of the front portion 122 is directly compressed by the impact, and thus has the most significant deformation. The sub-units 110, 1 12 of the first matrix unit 123 are equally compressed with the shortest length and the largest diameter. The nearer to the first matrix unit 123, the more compressed the matrix units 108 would be. In a macro view, the first thickness 124 is reduced to a minimum at the first matrix unit 123. Accordingly, an intensification of the matrix units 108 also occurs in the front portion 122, especially near the first matrix unit 123. Therefore, the first fraction of the unidirectional compressive energy is absorbed locally by the front portion 122 of the intermediate layer 106.

[0108] Secondly, a second fraction of the unidirectional compressive energy is gradually transmitted to the sub-units 1 10, 1 12 in the left portion 130 and the right portion 134, and finally to the sub-units 110, 1 12 in the rear portion 126. In particular, a second matrix unit 127 at the center of the rear portion 126 is furthest from the first matrix unit 123. Thus, the sub-units 1 10, 1 12 of the second matrix unit 127 are equally expanded with the longest length and the smallest diameter. The nearer to the second matrix unit 127, the more expanded the matrix units 108 would be. Meanwhile, the matrix units 108 in the left portion 130 and the right portion 134 are also expanded symmetrically, but to a less degree. In a macro view, the second thickness 128 is grown to a maximum at the second matrix unit 127 Meanwhile, the third thickness 132 and the fourth thickness 136 are also grown, but to a less degree. Accordingly, a rarefaction of the matrix units 108 also occurs in the left portion 130, the right portion 134 and the rear portion 126, especially near the second matrix unit 127. Therefore, the second fraction of the unidirectional compressive energy is transmitted to the left portion 130, the right portion 134 and the rear portion 126 of the intermediate layer 106.

[0109] Thirdly, a third fraction of the unidirectional compressive energy may be further transmitted through the intermediate layer 106 and reaches the inner shell 104. Similar to the intermediate layer 106, the inner shell 104 is made of an energy-absorbing material such that the third fraction is almost completely absorbed by the inner shell 104. Meanwhile, the protective head device 100 may additionally comprise a liner 142 (not shown) attached inside the inner shell 104. Even if the unidirectional compressive energy has a fourth fraction escaping from the inner shell 104, a wearer’s head is still well protected by the liner 142 since the liner 142 is also preferably made of energy absorbing material. In summary, the protective head device 100 can damp the unidirectional compressive energy by local absorption with the intermedia layer 106, maybe the inner shell 104 and the liner 142 in the impact area; and simultaneously by transmittance to the other areas of the intermediate layer 106 outside the impact area.

[01 10] Fig. 3 illustrates a cross-sectional view of a protective head device 100 in a rotational state. Only first sub-units 110 in the diagonally oriented configuration are shown for clarifying the deformation more clearly. A rotational force 144 is applied on the protective head device 100 and impacts directly to a center of the front potion 122 and a center of the rear portion 126 of the intermediate layer 106. The intermediate layer 106 deforms radially to a center of the protective head device 100. Accordingly, Fig.3 also shows that the contraction and expansion occur gradually within the intermediate layer 106.

[01 11 ] The rotational energy is damped by the intermediate layer 106 in several ways. Firstly, the first sub-units 1 10 are made of an energy-absorbing material. The first sub units 1 10 within the front portion 122 and the rear portion 126 thus locally absorb a first fraction of the unidirectional compressive energy by expanding the first sub-units 1 10. In a macro view, the first thickness 124 and the second thickness 128 are grown to a maximum. Accordingly, a rarefaction of the first sub-units 110 also occurs in the front portion 122 and the rear portion 126. Therefore, the first fraction of the unidirectional compressive energy is absorbed locally by the front portion 122 and the rear portion 126 of the intermediate layer 106.

[01 12] Secondly, a second fraction of the rotational energy is gradually transmitted to the first sub-units 1 10 in the left portion 130 and the right portion 134 that are contracted symmetrically to the center of the protective head device 100. In a macro view, the third thickness 132 and the fourth thickness 136 are deduced to a minimum. Accordingly, an intensification of the first sub-units 1 10 also occurs in the left portion 130 and the right portion 134. Therefore, the second fraction of the rotational energy is transmitted to the left portion 130 and the right portion 134 of the intermediate layer 106. In contrast to the first sub-units 110 in the diagonally oriented configuration, the second sub-units 1 12 in the complimentary diagonally oriented configuration undergo an opposite deformation, i.e. contraction in the front portion 122 and the rear portion 126; and expansion in the left portion 130 and the right portion 134.

[01 13] Thirdly, a third fraction of the rotational energy may be further transmitted through the intermediate layer 106 and reaches the inner shell 104. Similar to the intermediate layer 106, the inner shell 104 is made of an energy-absorbing material such that the third fraction is almost completely absorbed by the inner shell 104. Meanwhile, the protective head device 100 may additionally comprise the liner 142 (not shown) attached inside the inner shell 104. Even if the rotational energy has a fourth fraction escaping from the inner shell 104, a wearer’s head is still well protected by the liner 142 since the liner 142 is also preferably made of energy-absorbing material. In summary, the protective head device 100 can damp the rotational energy by local absorption with the intermedia layer 106, maybe the inner shell 104 and the liner 142 in the impact area; and simultaneously by transmittance to the other areas of the intermediate layer 106 outside the impact area.

[01 14] Fig. 4 illustrates a cross-sectional view of two first sub-units 110 in the diagonally oriented configuration on a plane in a neutral state. The first sub-units 110 are sandwiched and fixed between the outer shell 102 and the inner shell 104. Each of the first sub-unit 1 10 has a same cylindrical shape 120.

[01 15] Fig. 5 illustrates two second sub-units 1 12 in the complimentary diagonally oriented configuration on a plane in a neutral state. Similar to the first sub-units 1 10, the second sub-units 112 are sandwiched and fixed between the outer shell 102 and the inner shell 104. Each of the second sub-unit 1 12 has a same cylindrical shape 120.

[01 16] Fig.6 illustrates two matrix units 108 on a plane in a neutral state. The matrix units 108 are sandwiched and fixed between the outer shell 102 and the inner shell 104. Each of the matrix unit 108 comprises a first sub-unit 110 in the diagonally oriented configuration and a second sub-unit 1 12 in the complimentary configuration.

[01 17] Fig.7 illustrates a cross-sectional view of two first sub-units 1 10 in the diagonally oriented configuration on a plane for absorbing a unidirectional compressive energy. Under the unidirectional compressive force 138, the first sub-units 1 10 are immobile between the outer shell 102 and the inner shell 104 and undergo a first conformational change. Each of the first sub-unit 1 10 still keeps a same cylindrical shape 120.

[01 18] Fig. 8 illustrates a cross-sectional view of two second sub-units 1 12 in the complimentary diagonally oriented configuration on a plane for absorbing a unidirectional compressive energy. Similar to the first sub-units 1 10, the second sub units 1 12 under the unidirectional compressive force 138 are immobile between the outer shell 102 and the inner shell 104 and undergo a first conformational change. Each of the second sub-unit 112 still keeps a same cylindrical shape 120.

[01 19] Fig 9 illustrates a cross-sectional view of two matrix units 108 on a plane for absorbing a unidirectional compressive energy. The matrix units 108 under the unidirectional compressive force 138 are immobile between the outer shell 102 and the inner shell 104 and undergo a first conformational change.

[0120] Fig.10 illustrates a 3D perspective view of a matrix unit 108 on a plane under a unidirectional compressive force 138 in a neutral state. Fig. 10 shows that the matrix unit 108 is in the neutral state and each of the sub-units 110, 112 has the initial length 146 and the initial diameter 148. Fig 1 1 illustrates a 3D perspective view of a matrix unit 108 on a plane under a unidirectional compressive force 138. Fig. 1 1 (a) shows the same neutral state as Fig. 10. Fig. 1 1 (b) shows that the matrix unit 108 is under the unidirectional compressive force 138 and the sub-units 1 10, 1 12 undergo a first conformational change. Each of the sub-units has the compressed length 150 and the compressed diameter 152. Fig. 1 1 (c) shows that the unidirectional compressive force 138 applied on the matrix unit 108 becomes stronger and the sub-units 1 10, 1 12 still undergo a first conformational change but to a greater degree. Each of the sub-units has a shorter length and a larger diameter.

[0121 ] Fig 12 illustrates a cross-sectional view of four first sub-units 1 10 in the diagonally oriented configuration on a curve in a neutral state. The first sub-units 1 10 are sandwiched and fixed between the outer shell 102 and the inner shell 104. Each of the first sub-unit 1 10 has a same cylindrical shape 120. Similarly, Fig.13 illustrates a cross-sectional view of four second sub-units 1 12 in the complementary diagonally oriented configuration on a curve in a neutral state; and Fig.14 illustrates a cross- sectional view of four matrix units 108 on a curve in a neutral state.

[0122] Fig.15 illustrates a cross-sectional view of four first sub-units 1 10 in the diagonally oriented configuration on a curve for absorbing a rotational energy. Arrows in solid line denote deformation of the first sub-units 1 10. The first sub-units 110 are immobile between the outer shell 102 and the inner shell 104. Under the rotational force 144, each of the first sub-units 110 undergoes a second conformational change where each first sub-unit 1 10 is compressed but to a different degree. The nearer to the rotational force 144, the more compressed and less inclined the first sub-unit 110 would be. In addition, each of the first sub-unit 1 10 still keeps a same cylindrical shape 120.

[0123] Fig.16 illustrates a cross-sectional view of four second sub-units 1 12 in the complementary diagonally oriented configuration on a curve for absorbing a rotational energy. Arrows in solid line denote deformation of the second sub-units 1 12. The second sub-units 1 12 under the rotational 144 are immobile between the outer shell 102 and the inner shell 104. The second sub-units 1 12 under a second conformational change, but the second sub-units 112 are expanded, in contrast to the first sub-units 1 10. The farther from the rotational force 144, the more expanded and exaggerated the second sub-unit 1 12 would be. In addition, each of the second sub-unit 1 12 still keeps a same cylindrical shape 120.

[0124] Fig.17 illustrates a cross-sectional view of four matrix units 108 on a curve for absorbing a rotational energy. Arrows in solid line denote deformation of the matrix units 108. The matrix units 108 under the rotational force 144 are immobile between the outer shell 102 and the inner shell 104 and undergo a second conformational change.

[0125] Figures 18 and 19 demonstrate the redistribution and absorption of energy when a unidirectional force and a rotational force is applied respectively.

[0126] Figure 18 illustrates the energy from a unidirectional compressive force 138 is absorbed by the front/vertex/rear portion through compression of the structural material near the region of impact 138, and simultaneously through the expansion of the material elements in the left, right and rear portions. The rear portion locates at the opposite side of the protective head device 100 (also known as helmet), which is the most distant place from the unidirectional compressive force 138.

[0127] Figure 19 illustrates the energy from a rotational force applied at front portion is absorbed through compression of the material elements in the left and right portions and simultaneously through the expansion of the front and rear portions.

[0128] In summary, this structural design maximises the absorption of energy imparted by a force not only at the point of impart but through both the compression and expansion of structural elements redistributed throughout the intermediate layer.

[0129] Fig.20 illustrates a perspective view of stacked cylindrical fibers 158. A viscoelastic material is adopted for possessing a helical polymeric ultratructure 160 in a neutral state. Fig. 20 (a) shows only first sub-units 1 10 in the diagonally oriented configuration are shown for clarifying the deformation more clearly. Each of the first sub-units 1 10 in the diagonally oriented configuration of the intermediate layer 106 comprises a plurality of stacked cylindrical fibers 158 to permit expansion, compression and elastic recoil. The elastic recoil mechanism effectively transmits the unidirectional compressive energy, the rotational energy or the oblique impact energy to the outer shell 102 and the inner shell 104 of the protective head device 100. Fig. 20 (b) also shows that each of the cylindrical fibers 158 further comprises a plurality of helical polymeric ultratructures 160 combined in a parallel and stacked configuration. The helical polymeric ultratructures 160 are identical in shape and size. Fig. 20 (c) shows a single helical polymeric ultratructure 160 in a helical configuration. The helical polymeric ultratructure 160 can be either natural or synthetic. Similarly, the second sub-units 1 12 (not shown) in the complementary diagonally oriented configuration also comprise a plurality of stacked cylindrical fibers 158 and further a plurality of combined helical polymeric ultratructures 160.

[0130] Fig. 20 (d) shows an alternative model for the structure of the sub-units composing the matrix. A plurality of cylindrical elastic fibers 192 are encased in a washer 194 (i.e. a hollow cylinder of viscoelastic materials, such as rubber, sorbothane, Akton polymer, and etc.). Both units work independently when a compressive or tensile force is applied. For example, when a compressive force 196 is applied, the washer 194 is compressed, resulting in increased thickness and shorter length; the elastic fibers 192 contract. On the contrary, when a tensile force 198 is applied, the elastic fibers 192 expand under tension but the washer 194 encasing these fibers 192 is unaltered in dimensions.

[0131 ] Fig.21 illustrates a single helical polymeric ultrastructure 160 under an expanding force or under a compressive force. Arrows denote the expanding force or the compressive force. Similar to Fig. 20 (c), Fig. 21 (a) shows a single helical polymeric ultratructure 160 in the neutral state. The helical polymeric ultrastructure 160 has an elastic recoil property such that the helical polymeric ultrastructure 160 can undergo multiple cycles of expansion and compression. Fig. 21 (b) shows that an expanding force is applied to two ends of the helical polymeric ultrastructure 160, inducing the helical polymeric ultrastructure 160 to an expanded state. Fig. 21 (c) shows that a compressive force is applied to two ends of the helical polymeric ultrastructure 160, inducing the helical polymeric ultrastructure 160 to a compression state. When the compressive or tensile force is removed, the helical polymeric ultrastructure 160 will return to its neutral state by elastic recoil.

[0132] Fig.22 illustrates a cross-sectional view of spring coils 162 dispersed in the intermediate layer 106. The spring coils 162 spans between the inner shell 104 and the outer shell 102. Fig.23 illustrates a 3D perspective view of the protective head device 100 with spring coils 162. The spring coils 162 help the protective head device 100 achieve greater stability for the structure as a whole. Meanwhile, the spring coils 162 can also enable the inner shell 104 and the outer shell 102 to translate when the rotational force 144 is applied. In this way, all components of the protective head device 100 move as a whole in a same direction without rotation or change of shape; and thus the rotational energy caused by the rotational force 144 is further reduced.

[0133] Fig.24 illustrates a cross-sectional side-on view of air ventilation for the protective head device 100. Arrows denote directions of airflow. The matrix units 108 are discrete components with space 1 18 interspersed between two adjacent matrix units 108. On one hand, the space 1 18 leaves necessary room for the adjacent matrix units 108 to expand under the compressive force. On the other hand, the space 1 18 also acts as an air vent 164 of the intermediate layer 106 for circulating air through the intermediate layer 106. The outer shell 102 and the inner shell 104 are composed of a fenestrated structural material, permeable to air flow. As shown in Fig. 24, air from an ambient environment passes through the outer shell 102, the intermediate layer 106 via a first group 166 of the air vents 164, then the inner shell 104 and, finally reaches an inner space 170 inside the inner shell 104. Air also circulates in an opposite way: starts from the inner space 170, passes through the inner shell 104, the intermediate layer 106 via a second group 168 of the air vents 164, the outer shell 102, and finally reaches the ambient environment. Under the neutral state when no impact force is applied, the air vent 164 preferably has a uniform distribution in the intermediate layer 106. In this way, the wearer feels more comfortable since air can be exchanged homogeneously between the outer shell 102 and inter shell 104 through the intermediate layer 106. Permeability of airflow between the inner shell, intermediate layer and outer shell enable air inflow or egress during states of expansion or compression, respectively.

[0134] Fig.25 illustrates a cross-sectional aerial view of air ventilation for the protective head device 100. Arrows denote directions of airflow. In addition to the outer shell 102 and the inner shell 104, air can also flow into and out of the inner space 170 passing through the intermediate layer 106.

[0135] Fig.26 illustrates a cross-sectional view of air ventilation in the neutral state and under the unidirectional compressive force 138. Arrows in solid line denote directions of airflow. Fig. 26 (a) shows that the air vents 164 between first sub-units 1 10 are kept open for air ventilation through the intermediate layer 106 in a neutral state. Under the unidirectional compressive force 138, each of the air vents 164 decreases in size since the two adjacent first sub-units 110 expand as shown in Fig. 26 (b). In an extreme case when the unidirectional compressive force 138 is extremely strong, the air vents 164 are obliterated or closed when the two adjacent first sub-units 110 get in direct contact. In this case, the intermediate layer 106 cannot used for air ventilation.

[0136] Fig.27 illustrates a cross-sectional view and an overhead view of air ventilation. Similar to Fig. 26 (a), Fig. 27 (a) shows that the air vents 164 between first sub-units 1 10 are kept open for air ventilation through the intermediate layer 106 in a neutral state. Fig. 27 (b) demonstrates an overhead view accordingly. Each of the air vents 164 has a same round shape. The air vents 164 are uniformly distributed and form lines of air vents 164 in the overhead view. The lines of air vents 164 are separated.

[0137] Fig.28 illustrates a cross-sectional forward-facing view of air holes 178 in the outer shell 102. Each of the air hole 178 has a first opening 180 on a bottom surface in contact with the intermediate layer 106, and a body 184 between the bottom surface and the top surface. For efficient and easy air ventilation, the air holes 178 are connected to the air vents 164 of the intermediate layer 106 via the first openings 180 and also exposed outside of the protective head device 100 from a second openings 182. The air vents connect the air channels on the outer surface to the inner surface. This enables air to flow in or out between the head of the wearer and the external environment.

[0138] Fig.29 illustrates a cross-sectional view of air channels 186 in the outer shell 102. Arrows in solid line and dash line denote directions of airflow. Laminar airflows are formed in the air channels 186 for reducing airflow resistance, particularly when the wearer travels at a high speed. The air channels 186 are also interconnected to the air vents 164 in the intermediate layer 106 for air flowing from the outer shell 102 to the inner shell 104 through the intermediate layer 106. Air flowing internally through the anterior air vent can circumvent the wearer’s head before flowing out through the posterior air vent.

[0139] Fig.30 illustrates a perspective view of the air channels 186 in the outer shell 102 from top of the protective head device 100. Arrows in solid line denote directions of airflow. The air channels 186 are made across the outer shell and distributed in a symmetrical manner. Each of the air channels 186 has an inlet 188 for incoming airflow and an outlet 190 for outgoing airflow.

[0140] Fig.31 illustrates a 3D diagrammatic view of laminar airflow across the protective head device 100. Arrows denote directions of airflow. Air from the ambient environment flows into the inlets 188, along the air channels 186 for forming laminar airflows, and finally out of the outlets 190.

[0141 ] Fig.32 illustrates a method 200 of making the protective head device 100. The method 200 comprises a first step 202 of providing an outer shell 102; a second step 204 of providing an inner shell 104; a third step 206 of providing an intermediate layer 106; and a fourth step 208 of arranging the intermediate layer 106 between the outer shell 102 and the inner shell 104 for damping energy of an impact. [0142] Fig.33 illustrates a method 300 of using the protective head device 100 when the protective head device 100 is made of discrete components. The method 300 comprises a first step 302 of wearing an inner shell 104; a second step 304 of installing an intermediate layer 106 on the inner shell 104; and a third step 306 of installing an outer shell 102 on the intermediate layer 106.

[0143] Fig.34 illustrates an apparatus 400 for testing the protective head device 100. Fig. 34 shows that the apparatus 400 comprises a protective head device 100 as described above, a first pressure sensor 402 mounted on the outer shell 102; a second pressure sensor 404 mounted the inner shell 104; The second pressure sensor 404 is also mounted on a wall 408 opposite to the inner shell 104.

[0144] Fig.35 illustrates result analysis of the testing in Fig.34. The first testing is conducted by applying the unidirectional compressive force 138 and measuring a pressure difference 410 between the first pressure sensor 402 and the second pressure sensor 404. The second testing is conducted by measuring the thickness 412 of the intermediate layer 106 and the pressure difference 410.

[0145] In the application, unless specified otherwise, the terms "comprising", "comprise", and grammatical variants thereof, intended to represent "open" or "inclusive" language such that they include recited elements but also permit inclusion of additional, non- explicitly recited elements.

[0146] As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 5% of the stated value, more typically +/- 4% of the stated value, more typically +/- 3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1 % of the stated value, and even more typically +/- 0.5% of the stated value.

[0147] Throughout this disclosure, certain embodiments may be disclosed in a range format. The description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. [0148] It will be apparent that various other modifications and adaptations of the application will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the application and it is intended that all such modifications and adaptations come within the scope of the appended claims.

Reference Numerals

100 protective head device;

102 outer shell;

104 inner shell;

106 intermediate layer;

108 matrix unit;

1 10 first sub-unit;

1 12 second sub-unit;

1 14 outer surface;

1 16 inner surface;

1 18 space;

120 cylindrical shape

122 front portion;

123 first matrix unit;

124 first thickness;

125 first diameter;

126 rear portion;

127 second matrix unit;

128 second thickness;

129 second diameter;

130 left portion;

132 third thickness;

133 third diameter;

134 right portion;

136 fourth thickness;

137 fourth diameter;

138 unidirectional compressive force;

140 imaginary axis;

142 liner;

144 rotational force;

146 initial length (in a neutral state); 148 initial diameter (in a neutral state);

150 compressive length;

152 compressive diameter;

154 compressed length on a curve;

156 compressed diameter on a curve;

158 cylindrical fibre;

160 helical polymeric ultratructure (also known as ultrastructure); 162 spring coil;

164 air vent;

166 first group of air vents;

168 second group of air vents;

170 inner space;

176 distance;

178 air hole;

180 first opening;

182 second opening;

184 body;

186 air channel;

188 inlet;

190 outlet;

192 cylindrical elastic fibres (i.e. fibers);

194 washer;

196 compressive force;

198 tensile force;

200 method of making the protective head device;

202 first step;

204 second step;

206 third step;

208 fourth step;

300 method of using the protective head device;

302 first step;

304 second step; 306 third step;

400 apparatus;

402 first pressure sensor;

404 second pressure sensor;

408 wall

410 pressure difference;

412 thickness;

500 method of testing the protective head device; 502 first step;

504 second step;

506 third step;

508 fourth step;

510 fifth step;

512 sixth step;

514 seventh step;

516 eight step;

Claims

1. A protective head device comprising:

> an outer shell for withstanding an impact;

> an inner shell for covering a head; and

> an intermediate layer connected between the outer shell and the inner shell;

wherein the intermediate layer is configured to reduce both unidirectional and rotational impact.

2. The protective head device of claim 1 , wherein

the intermediate layer comprises a plurality of matrix sub-units for diverting the impact.

3. The protective head device of claim 2, wherein

the matrix sub-units are spaced apart from each other.

4. The protective head device of claim 2, wherein

at least one of the matrix sub-units is hollow.

5. The protective head device of claim 1 , further comprising:

spring coils placed interspersed through the intermediate layer.

6. The protective head device of claim 2, wherein

the matrix sub-units are aligned for providing at least one ventilation channel.

7. The protective head device of claim 1 , wherein

at least one of the outer shell and inner shell has perforations for air ventilation.

8. The protective head device of claim 1 , wherein

the inner shell, the outer shell or both are made of at least one flexible material.

9. The protective head device of claim 1 further comprising

at least one sensor for monitoring physical parameters of the protective head device during usage.

10. The protective head device of claim 1 further comprising

a headset, an earpiece, a light indicator, a ventilation fan, a radio transmitter, a radio receiver, a laser pointer, an alarm, a recorder, an illuminator, a head strap, a rain cover, a wind shield, a neck supporter, a neck protector, a face guard, a hairclip, a cooling pad, or a combination of any of these.

1 1. A method for making a protective head device comprising:

> providing an outer shell for withstanding an impact;

> providing an inner shell for covering a head;

> providing an intermediate layer;

> providing the intermediate layer connected between the outer shell and the inner shell; and

> arranging structure of the intermediate layer to reduce both unidirectional and rotational impact.

12. The method of claim 1 1 , wherein

the arranging structure of the intermediate layer comprises providing a plurality of matrix sub-units for diverting the impact.

13. The method of claim 12, wherein

the providing the plurality of matrix sub-units comprises spacing the matrix sub- unitsapart from each other.

14. The method of claim 11 further comprising

providing at least one releasable catches for detaching a part of the protective head device.

15. The method of claim 11 further comprising

installing at least one sensor on the protective head device for monitoring physical parameters.