Protective lining that can be coupled to the inner surface of a helmet, helmet comprising said lining and use thereof in order to reduce rotational acceleration transmitted to a user

Abstract

A protective liner, attachable to the inner surface of a helmet, comprising an inner face and an outer face oriented towards the inner surface of the helmet, wherein the joining of faces gives rise to a plurality of inflatable chambers permeable to water vapour and connected by means of pressurised air distribution channels. The chambers and channels form a single body extending at least along the inner surface of the helmet above the Frankfurt plane. The outer face comprises a layer of rigid material while the inner face comprises a layer of elastic material, whose area expands when the chambers are filled with air, such that the expansion in volume occurs mainly by means of the deformation of the elastic layer.

Claims

1. A protective liner configured to be attached to an inner surface of a helmet, the protective liner comprises an inner face, configured to come into contact with a user's head and an outer face oriented towards the inner surface of the helmet when the protective liner is attached to the helmet and worn by the user, wherein a union of the inner face and the outer face forms a plurality of inflatable chambers interconnected by channels through which air is distributed, wherein the plurality of chambers and channels form a single body that is configured to extend along the inner surface of the helmet, including the inner surface on inner side portions of the helmet, wherein the chambers are permeable to water vapour and wherein the outer face comprises a layer of rigid material while the inner face comprises a layer of elastic material, wherein an area of the layer of elastic material increases when the chambers are filled with air, such that, upon inflation, expansion of the chambers in a radial direction when the protective liner is attached to the helmet of the protective liner occurs mainly through deformation of the elastic layer; and wherein the outer face and the inner face comprise respective layers of hydrophilic thermoplastic polyurethane welded together forming the chambers interconnected by channels.

2. The liner, according to claim 1, wherein the layer of rigid material and the layer of elastic material are colaminated respectively with the layer of hydrophilic thermoplastic polyurethane comprised by the outer face and with the layer of hydrophilic thermoplastic polyurethane comprised by the inner face.

3. The liner, according to claim 2, wherein the layer of rigid material is a polyamide fabric having a linear weight comprised between 70 and 300 dtex.

4. The liner, according to claim 2, wherein the layer of elastic material of the inner face has a linear elongation comprised between 20% and 150% with respect to an initial unloaded length of the layer of elastic material, and an elastic return greater than 95%.

5. The liner, according to claim 4, wherein the layer of elastic material of the inner face is a mesh-type stretch fabric or a woven elastane-based fabric.

6. A helmet for users of two-wheeled vehicles or for sports people wherein the inner surface of the helmet is formed by a protective liner according to claim 1.

7. A method of protecting a user's head, comprising wearing the liner according to claim 1 to reduce the rotational acceleration transferred to the liner user's head in case of accident.

8. A method of protecting a user's head, comprising wearing a helmet according to claim 6 to reduce the rotational acceleration transferred to the helmet user's head in case of accident.

9. A helmet for users of two-wheeled vehicles or for sports people wherein the inner surface of the helmet is formed by a protective liner according to claim 1.

10. A helmet for users of two-wheeled vehicles or for sports people wherein the inner surface of the helmet is formed by a protective liner according to claim 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The attached drawings illustrate, by way of non-limiting example, a preferred embodiment of the protective liner object of the invention. In said drawings:

(2) FIG. 1 shows a plan view of the protective liner object of the invention, seen from its inner face intended to come into contract with a user's head; and

(3) FIG. 2 shows a schematic sectional view of the layers of one of the chambers of the protective liner of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows, in an extended position, a protective liner 1 attachable to the inner surface of a helmet (not shown). The liner 1 is formed from a plurality of inflatable chambers 4 interconnected by channels 5 through which air is distributed, supplied for example by a pump through various valves, for example valve 9 of FIG. 1. In particular, it can be observed that, according to the liner 1 represented, the internal space of the liner 1 is divided by oblong partitions 10 whose ends are separated by a small distance from the perimeter contour of the liner 1 or from an internal contour that defines the contours of the chambers 4 themselves. This separation space is that which defines the passage of air from one chamber 4 to another, i.e. it is the space that forms the channels 5. The distance between two consecutive partitions 10 is designed to adapt to the specific shape of the head to be protected. Thus, the volume of the inflatable chambers 4 is variable according to the amount of air introduced. It is the user who, by controlling the inflation valve 9, regulates the amount of air until his or her head comes into contact with the inner face 2 of the liner 1 (the outer face 3 is the opposite face oriented towards the inner surface of the helmet). The user inflates the chambers 4 up to a level in which the pressurised air has occupied all the chambers 4 interconnected by the channels 5 at a homogeneous pressure, feeling a certain firmness from the chambers 4 on establishing contact with his or her head but without the liner 1 oppressing it excessively. The air is distributed through the chambers 4 depending on the space available between the head and the helmet at a homogeneous pressure in all the chambers, but with said pressure generating a variable chamber volume (or thickness) in accordance with the morphology of the head and the relative space in the zone of said chamber between the helmet and the head. In an operational protection position there should not be empty space allowing movement between the helmet and the head, i.e. the space must be occupied by the liner 1. If the user observes that the liner has been excessively inflated, he or she uses the valve 9 to deflate it to the appropriate degree in which the user feels comfortable but safe. It is proved for that the valve 9 may be disassembled from the helmet in order to wash it.

(5) As can be observed in FIG. 1, the plurality of chambers 4 and channels 5 of the liner 1 form a single body that extends throughout the inner surface of the helmet at least above the Frankfurt plane or tragus-orbitale horizontal line. The Frankfurt plane is that which is formed by the imaginary line drawn from the lower end of the orbit (lower margin of the ocular orbit) to the upper edge of the external auditory canal (ear tragus or cartilage). The liner 1 may extend further than the Frankfurt plane and even reach the inner surface of the helmet corresponding to the cheek zone or even that corresponding to the nape zone. The protective liner 1 is placed coupled inside the helmet on the outer face 3. The liner 1 can be coupled to the helmet shell by means of appropriate fixing means (not shown) which may be provided in zones of its edges or in specific flat zones. For example, certain portions of the perimeter edge of the liner 1 may be joined to portions of fabric or strips having fixing means for joining the liner 1 to the inner surface of the helmet in a firm manner, removable (so as to enable disassembly) or even allowing a certain relative movement between the liner 1 and the impact-absorbing element.

(6) In the cross-section shown in FIG. 2, it can be observed that the outer face 3 and the inner face 2 comprise respective layers of hydrophilic thermoplastic polyurethane layers 8 welded together in those sections that form the contours of the chambers 4 and channels 5, as a result of which the chambers 4 are permeable to water vapour, due to which the liner 1 is not uncomfortable or a source of heat and humidity due to being breathable. The helmet wherein the protective liner 1 is disposed may have its own aeration system through which the air in the interior of the helmet can communicate with the outside air. Another weldable material having equivalent properties with regards to its permeability to water vapour can be used instead of hydrophilic thermoplastic polyurethane.

(7) The outer face 3 comprises, in addition to the hydrophilic thermoplastic polyurethane layer 8, a layer of rigid material 6, preferably a polyamide fabric having a linear weight comprised between 70 and 300 dtex.

(8) Furthermore, the inner face 2 comprises, in addition to its respective layer of hydrophilic thermoplastic polyurethane 8, a layer of elastic material 7 whose area expands when the chambers 4 are filled with pressurised air, such that the expansion in volume of the liner 1 occurs mainly by means of the deformation of the layer of elastic material 7. Preferably, this layer of elastic material 7 has a linear elongation comprised between 20% and 150% with respect to its initial unloaded length and an elastic return greater than 95%. Possible elastic materials include mesh-type stretch fabrics (knitted fabric in English) and woven elastane-based fabrics (woven fabrics in English). Advantageously, the inner face 2 has a covered heat-welded seam construction adapted to create an uneven, three-dimensional shape when the liner 1 is inflated. The covered seam technique, also known as heat-welded seam, involves placing adhesive tape or welding tape over the seam, and offers a high degree of protection as it does not leave holes. FIG. 2 shows that the inner face 2 is that which separates more from the welding line between the hydrophilic thermoplastic polyurethane layers 8, i.e. that when the chambers 4 are inflated, most of the chamber volume is displaced towards the inner face 2, that which will come into contact with the head. This distribution of volume enables the liner 1 to adapt perfectly to different types of heads (round, flat, oval, egg or inverted egg-shaped heads, etc.), by inflating the liner 1 to a greater or lesser extent.

(9) As shown in FIG. 2, the layer of rigid material 6 and the layer of elastic material 7 are colaminated respectively with the hydrophilic thermoplastic polyurethane layer 8 comprised by the outer face 3 and with the hydrophilic thermoplastic layer 8 comprised by the inner face 2.

(10) The differential structural behaviour between the layer of rigid material 6 and the layer of elastic material 7 favours a unidirectional inflation of the chambers 4, such that when they are inflated they do not shrink laterally, due to which the inflated chambers 4 adopt and preserve the volumetric shape for which they were intended during the inflation process, mainly the shape conferred by the inner face 2, while simultaneously maintaining perfect cohesion between the outer face 3 of the liner 1 and the interior of the helmet.

(11) This unidirectional inflation of the chambers contributes to reducing rotational acceleration, which is achieved by means of the air layer of the chambers 4 created between the outer face 3 of a rigid material and the inner face 2 of an elastic material of the liner 1, as it has been proven that the air disposed in the chambers 4 thus formed is practically incapable of transferring tangential/shear stress. The protective liner 1 causes the helmet to which it is coupled to have an effect on the user similar to that of floating on his or her head. The join between the outer face 3 and the inner face 2 forms something similar to radial walls when the chambers 4 of the protective liner 1 are full of air, due to which they do not come into contact with the user's head. As there is no contact, there is no friction between the liner 1 and the user's head, due to which, in case of accident, the rotational acceleration generated is not transferred to the user's head, protecting it from the brain injuries to which it would be exposed with a conventional liner.

(12) Furthermore, it should be noted that the liner 1 allows comfortable adjustment to the user's head, being easy to introduce and remove the head from a helmet having the liner 1 in its interior. The configuration of the chambers 4 and of the channels 5 provides uniform pressure and good adaptability to different types of heads. The liner 1 is safe, long-lasting, washable, breathable and easy to use. In order to use the liner 1, the user must put on the helmet, adjust the retention system of the helmet and activate the inflation system formed, inter alia, by the inflating pump and the valve 9, which are both preferably disposed in the interior of the helmet and can be activated, for example, by means of a button easily accessible by the user, until he or she feels that a degree of pressure that affords optimum comfort has been reached. After performing the activity associated with the helmet, such as for example riding a motorcycle or participating in a competition or sporting activity, before removing the helmet the user has the option of activating the valve 9 button to partially deflate the liner 1 and then conveniently proceed to remove the helmet from his or her head.

(13) Moreover, from the manufacturing point of view, a helmet having the liner 1 makes it possible to achieve a good quality-cost ratio, since the adaptability of the dimensions of the liner 1 once inflated enables the adaptation of a single helmet, with a certain shell, to users with different types of heads.