WO2015087030A1

WO2015087030A1 - Helmet comprising air vents

Info

Publication number: WO2015087030A1
Application number: PCT/GB2014/000488
Authority: WO
Inventors: Secretary Of State For Defence The; Simon John HOLDEN
Original assignee: Secretary Of State For Defence The
Priority date: 2013-12-09
Filing date: 2014-11-26
Publication date: 2015-06-18
Also published as: GB2521001A; GB201321652D0; EP3079515A1; EP3079515B1

Abstract

There is provided a helmet (10) comprising air vents (32) and covers (30, 30a) for opening and closing the air vents. The covers are configured to hinge outwardly from the helmet to open the air vents. Since the covers are configured to hinge outwardly (38) from the helmet, the covers still provide protection against projectiles that emanate from a direction (DF) towards which the covers pivot when hinging, even when the air vents are opened. Optionally, the covers may be configured to hinge outwardly from the helmet towards a front of the helmet, so that the covers prevent projectiles which originate from the direction in which a wearer of the helmet is facing from entering the air vents, even when the air vents are open.

Description

HELMET COMPRISING AIR VENTS

Technical Field of the Invention This invention relates to a helmet comprising air vents. The air vents are intended^to help keep a wearer of the helmet cool.

Background to the Invention Helmets are typically used to protect human heads from the external environment, for example during sports or military operations. It is known to provide air vents within helmets to help prevent overheating of a wearer of the helmet.

Overheating is a significant problem, particularly in the context of military use where helmets may need to be physically thick and/or dense to provide sufficient protection, and where wearers may need to operate in hot environments.

It is also known to provide adjustable air vents within helmets, so that the air vents can be opened or closed depending upon the user's requirements. Japanese patent application publication JP H 11 -22271 OA discloses a protective helmet that has an air vent which can be opened and closed by a lid under the control of a shape memory metal. The lid moves perpendicularly upwards from a surface of the helmet to open an air vent when the temperature inside the helmet exceeds a preset temperature. In order to provide effective cooling in hot environments, it may be necessary to provide multiple air vents in order to improve heat transfer away from the interior of the helmet.

One of the problems with providing helmets with air vents is that the open air vents can reduce the amount of protection provided by the helmet. This is particularly true in military scenarios, where bullets and/or fragmentation may simply bypass the protective elements of the helmet by entering the helmet through the open air vents.

It is therefore an aim of the invention to provide an improved helmet. Summary of the Invention

According to an embodiment of the invention, there is provided a helmet comprising a plurality of air vents, and covers for opening and closing the air vents, wherein the covers are configured to hinge outwardly from the helmet to open the air vents.

Since the covers are configured to hinge outwardly from the helmet, the covers still provide protection against projectiles that emanate from a direction towards which the covers pivot when hinging, even when the air vents are Opened. Specifically, the use of a hinge means that there are no gaps between an edge of the cover where the hinge is located and the helmet, even when the covers are hinged to open the air vents. Each cover may be configured to hinge outwardly from the helmet about a hinge axis that is parallel to an exterior surface of the helmet adjacent the hinge axis. The covers may form an exterior of the helmet. The covers may close the air vents by covering over the air vents, and open the air vents by uncovering the air vents.

Advantageously, each cover may be configured to hinge outwardly from the helmet in an arc towards a front of the helmet, so that the hinges are placed at sides of the covers nearest to the front of the helmet. Since projectiles may be most likely to originate from the direction in which a wearer of the helmet is facing, placing the hinges at the sides of the covers nearest to the front of the helmet means that the helmet protects against projectiles originating from such a direction, even when the air vents are opened. Furthermore, the helmet may comprise a front portion configured to cover the front half of the top of a wearer's head and a rear portion configured to cover the rear half of the top of the wearer's head, and all of the covers may be positioned at the front portion. Since all of the covers are positioned at the front portion, there are no covers at the rear portion.

Therefore, a projectile originating from behind a wearer of the helmet should not be able to enter any of the air vents eyen when the air vents are opened by the covers, since all of the opened air vents are positioned at the front portion, which is obscured by the rear portion to any against projectiles originating from behind the wearer of the helmet. Therefore, projectiles originating from both directly in front and directly behind the wearer may be prevented from entering the helmet via the air vents, even when the air vents are opened by the covers. The hinging of the cover outwardly from the helmet typically comprises the movement of the cover in a direction outwardly from the helmet. A direction outwardly from the helmet is typically considered to be a direction from an interior volume of the helmet where the wearer's head is intended to fit, to the external environment outside of the helmet. The outward direction may for example pass substantially perpendicular through an exterior surface of the helmet where the cover is located.

The helmet may comprise an outer shell and a liner inside of the outer shell, and the covers may be configured to hinge outwardly from the liner. The covers may be formed by portions of the outer shell that are configured to hinge away from the liner, for example each cover may be hingedly attached to a static portion of the outer shell by a living hinge of the outer shell. In other words, the hinge may comprise or be formed from the same material as the static portion of the outer shell and the cover. One suitable material is a bistable composite, which can flip from one stable state to another by means of a solid state actuator (such as, for example, a piezoelectric actuator).

The liner may be configured to contact the head of a person wearing the helmet, and may for example comprise a web of straps that can be tightened about a wearer's head to help fit the helmet to the wearer. Alternatively, the liner may comprise a soft padded layer that fits around the wearer's head.

Advantageously, the helmet may comprise a support shell with apertures that form the air vents. The covers may be positioned above the apertures so that they reveal the apertures when they are hinged away from the support shell. The support shell may be between the outer shell and the liner, and the covers may be hingedly attached to the support shell rather than the outer shell. For example, the outer shell may be comprised of multiple covers that are each attached to the support shell by respective hinges. The covers may form a tessellation with one another when the air vents are closed, so that the covers can together form a large portion of the outer shell and reveal a large number and/or large area of air vents when they are opened.

Advantageously, the covers may be controlled by solid state actuators to open and close the air vents. The opening and closing of the air vents may be controlled automatically, for example by controlling solid state actuators such as dielectric elastomers or shape memory metals/polymers to move the covers about their hinges. Other suitable solid state actuators are piezoelectric, thermal and magnetostrictive actuators.

In particular, the helmet may comprise an acoustic shot detector and a controller, the controller configured to control the covers to open and close the air vents based upon the acoustic shot detector. Therefore, the covers may be automatically moved to cover the air vents when the acoustic shot detector registers the presence of gunfire. Acoustic shot detectors are known in the. art, and so their detailed construction is not described herein.

The covers are preferably armour elements that provide ballistic protection. For example, the covers may provide at least a protection level of a V50 of 380 m/s against a 1.1 gram (17 Grain) untumbled chisel nosed fragment simulating projectile (FSP) as specified in STAN AG 2920 edition 2. Such a protection level is easily achievable by those skilled in the art using known techniques for forming armour elements.

The covers may take the form of a ballistic tile having a textile armour covering. The tile may comprise any suitable ballistic material, for example Ultra High Molecular Weight Polyethylene (UHMWPE) or a bistable composite such as a carbon fibre composite laminate. Suitable textile armours are Aramid fibre or UHMWPE fibre. The outer shell and/or support shell may also comprise any suitable ballistic material. In one preferred embodiment, the outer shell and/or support shell has a ballistic composite construction such as, for example, - carbon fibre reinforced composite with armour fibre (e.g. Aramid fibre or UHMWPE fibre). The outer shell and/or support shell may comprise the same material(s) as the covers. . Brief Description of the Drawings

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

Fig. 1 shows a schematic diagram of a helmet according to a first embodiment of the invention, with covers in a position covering air vents;

Fig. 2 shows a schematic diagram of the helmet of Fig. 1, with the covers in a position uncovering the air vents;

Fig. 3 shows a schematic diagram of the inside of the helmet of Fig. 1, looking in from section AA marked on Fig. 1 ;

Fig. 4 shows a schematic cross-sectional diagram of part of the helmet of Fig. 1, taken along line B marked on Fig. 1 ;

Fig. 5 shows a schematic cross-sectional diagram of the same part of the helmet shown in Fig. 4, taken along line C marked on Fig. 2;

Fig. 6 shows a schematic plan diagram of a helmet according to a second embodiment of the invention;

Fig. 7 shows a schematic cross-sectional diagram of the helmet of Fig. 6, taken along line D marked on Fig. 6, with a cover in a closed position covering an air vent; and

Fig. 8 shows another schematic cross-sectional diagram of the same part of the helmet as in Fig. 7, but with the cover in an open position uncovering the air vent.

The drawings are purely illustrative and are not to scale. Same or similar reference signs denote same or similar features.

Detailed Description

A first embodiment of the invention will now be described with reference to Figs. 1 - 5, The schematic diagram of Fig. 1 shows a person 1 wearing a helmet 10 according to the first embodiment. The helmet 10 comprises a front portion 12 and a rear portion 14, the front portion 12 covering a front half of the person's head and the rear portion 14 covering a rear half of the person's head. The front portion 12 and the rear portion 14 meet one another at a point 15 which is substantially at the very top of the person's head, in the region of the vertex of the head. The divide 19 between the front and rear portions extends downwardly from the point 15 on either side of the person's head.

The front portion 12 is covered with covers 30 that tessellate with one another to form an outer shell of the helmet. Each cover 30 is made from a UHMWPE (Ultra High Molecular Weight Polyethylene) tile with an Aramid fibre covering. The covers 30 cover over air vents (not visible in Fig. 1). The UHMWPE tiles are rated to exceed a protection level of a V50 of 380 m/s against a 1.1 gram (17 Grain) untumbled chisel nosed fragment simulating projectile (FSP) as specified in STANAG 2920 edition 2.

The front portion 12 comprises a small overhang 16 at the very front of the helmet. The rear portion 14 is made from a plastics resin incorporating Aramid fibres, and does not have any of the covers 30. The helmet 10 further comprises a chinstrap 20 to help secure the helmet upon the head on the person 1.

The schematic diagram of Fig. 2 shows the person 1 wearing the helmet 10, with the covers 30 having been hinged outwardly from the helmet 10 towards the front of the helmet 10 to uncover the air vents 32. The air vents 32 are formed as apertures through a support shell 34. Each one of the covers 30 is mounted on the support shell 34 with a respective hinge. The support shell 34 is made from a plastics resin incorporating Aramid fibres, and in this particular embodiment is integrally formed with the rear portion 14.

The hinge of each cover has a hinge axis that is parallel to the exterior surface of the helmet adjacent the hinge axis. As shown in Fig. 2, the cover 30a has a hinge axis 35 that is parallel to the exterior surface 36 adjacent the hinge axis 35. The hinge axis 35 is at the side of the cover 30a that is nearest to the front of the helmet, such that^' the cover 30a hinges outwardly from the helmet in a direction 38 that arcs towards the front of the helmet. The direction 38 is in a direction from the interior of the helmet where the head of the person is located, to the external environment, and is substantially perpendicularly to the outer of the helmet when the cover 30a is located in its closed position.

Even when the air vents are open, the helmet 10 still provides good protection against projectiles, since any projectiles approaching from in front of the wearer in a direction DF will not be able to reach the air vents 32 due to the covers 30 being in the way of the projectile, and any projectiles approaching from behind the wearer in a direction DR will not be able to reach the air vents 32 due to the rear portion 14 being in the way of the projectiles.

The schematic diagram of Fig. 3 shows the inside of the helmet 10, looking in from section AA marked on Fig. 1. The small overhang 16 at the front of the helmet is visible at the top of Fig. 3. The chinstrap 20 is connected to liner that is formed of a web of straps 42, . 44, 46 and a fabric layer 50. The fabric layer 50 lies against the support shell 34 and covers the air vents 32 to prevent ingress of dust or dirt into the helmet. The fabric layer 50 is thin and presents only minimal resistance to airflow through the air vents 32.

.

The strap 42 loops over the top of the wearer's head from ear to ear, the strap 44 loops over the top of the wearer's head from front to back, and the strap 46 encircles around the circumference of the wearer's head and is connected to the straps 44 and 46. The straps 42, 44, and 46 are anchored to the support shell 34 through the fabric layer 50, and may be adjusted to suit the wearer's head.

The schematic diagram of Fig. 4 shows a cross-sectional diagram through the helmet when the covers 30 are opened, taken along line B marked in Fig. 1, and the schematic diagram of Fig. 5 shows a cross-sectional diagram through the helmet when the covers 30 are closed, along line C marked in Fig. 2.

Figs. 4 and 5 both show the support shell 34 having apertures therethrough which form air vents 32. An inner side of the support shell 34 is connected to the fabric layer 50, and an outer side of the support shell 34 supports the covers 30 at hinges 52. The hinges 52 are formed by adhering or otherwise attaching the Aramid fibre covering of the covers 30 to the support shell 34 along the lower edge of the covers 30, as shown. The Aramid fibre covering has sufficient flexibility for the covers to be movable between the closed position shown in Fig. 4 and the open position shown in Fig. 5. In the open position, air 56 can flow through the air vents 32 to help cool the wearer of the helmet. Clearly, the fabric layer 50 could be omitted or apertures could be cut through it to improve the airflow 56 from inside to outside of the helmet.

The opening and closing of the air vents 32 by the covers 30 is effected by actuators 54, which are configured to straighten, to force the covers 30 to move upwardly away from the helmet. For each cover 30, there is at least one actuator 54, and the actuator is connected from the support shell 34 to the cover 30, to actuate pivoting of the cover 30 about the hinge 52. In this particular embodiment the actuator 54 is a solid state actuator in the form of a shape memory metal that responds to electrical control currents that heat the shape memory metal. Although, other types of actuator such as shape memory polymers that respond to increased temperatures inside of the helmet, may alternatively be used. For both shape memory metals and shape memory polymers, a heating of the metal/polymer is used to raise the temperature of the metal/polymer above a transition temperature where it tends to straighten.

Each shape memory metal actuator 54 is connected to two electrical conductors (not shown in Figs) at opposite ends of the shape memory metal actuator 54, for supplying current to ohmically heat the shape memory metal actuator 54 when the cover 30 to which the shape memory metal actuator 54 is connected is to be moved outwardly from the helmet to open the air vent. The two electrical conductors are conductive wires, which are electrically connected to a controller 48 shown in Fig. 3. The controller 48 is mounted to the support shell 34, and determines when the air vents are to be opened, for example in response to a command from a push-button, which a user may push to instruct the opening of the air vents. When the controller determines that the air vents are to be opened, it drives a current through each shape memory metal actuator 54 via the conductive wires, to ohmically heat the shape memory metal actuators 54 and force the covers 30 to uncover the air vents 32. The current is only applied for a short time, allowing the shape memory metal actuator 54 to cool, whilst the air vents 32 remain open. If the wearer wishes to subsequently close the air vents 32, then the wearer can manually push the covers downwards to cover the air vents 32, deforming the shape memory metal actuators 54. The shape memory metal actuators 54 remain is this deformed state until they are heated again, upon which they straighten again to open the air vents 32. In this embodiment, the controller 48 is connected to an acoustic shot detector 18, shown in Fig. 1. The acoustic shot detector 18 sends a signal to the controller 48 when a shot is detected, and in response the controller 48 will not send any currents to the shape memory metal actuators 54 that would cause the covers 30 to open. Furthermore, the covers 30 could be fitted with additional actuators that the controller 48 would use to actively close the covers 30 whenever a shot was detected by the acoustic shot detector 18. For example, shape memory metal actuators that contract when heated to pull the covers 30 downwards could be fitted to the covers 30. A helmet 95 according to a second embodiment of the invention will now be described with reference to Figs. 6 to 8. The helmet 95 is the same as the helmet 10 of the first embodiment, except for the details shown in Figs. 6 to 8. The schematic diagram of Fig. 6 shows a plan view of the helmet 95, having front and rear portions marked as 90 and 91 respectively. The helmet comprises two covers within the front portion 91, which can be moved outwardly from the helmet to uncover air vents.

The helmet 95 comprises an outer shell 62 that is formed of rigid portions 65, 66, and

67 enveloped within an Aramid fibre covering 63. The rigid portions are all formed of a plastics resin incorporating Aramid fibres. The boundaries of the rigid portions are marked with dashed lines to indicate that the rigid portions are inside of the Aramid fibre covering 63. The rigid portion 65 extends over most of the area of the helmet, although has two rectangular shaped holes within it, where the rectangular rigid portions 66 and 67 fit. The rigid portions 66 and 67 are the same as one another, and are on opposing sides of the helmet. The portion of the Aramid fibre covering 63 that covers the rigid portion 66 is cut along first, second, and third sides of the rigid portion 66, as indicated by the line 69.

Therefore, the rigid portion 66 is able to hinge about the rigid portion 65, via a living hinge

68 that is provided by the un-cut Aramid fibre covering 63 at the fourth side of the rigid portion 66. The fourth side is the side of the rigid portion 66 that is closest to the front of the helmet. Shape memory metal actuators 75 are connected between the rigid portions 65 and 66 to control the relative hinging of the rigid portions 65 and 66. The other rigid portion 67 is arranged in just the same way as the rigid portion 66.

Figs. 7 and 8 show cross sectional diagrams of the helmet 95, taken both along line D marked on Fig. 6. Fig. 7 shows the helmet 95 with the cover formed by rigid portion 66 in a closed position, and Fig. 8 shows the helmet 95 with the cover formed by rigid portion 66 in an open position. As seen in Fig. 7, the helmet 95 of the second embodiment does not include a support - shell for supporting the rigid portions 66 and 67. Instead, the rigid portions 66 and 67 are supported by the other portions of the outer shell which remain static relative to the helmet 95, such as the rigid portion 65.

A fabric liner 60 is adhered directly to the inside of the outer shell 62, except for at regions of the outer shell that correspond to the rigid portions 66 and 67, such as region 80. The shape memory metal actuator 75 is bonded to the rigid portion 65 at point 77, arid to the rigid portion 66 at the point 76.

When the shape memory metal actuators 75 are actuated by driving a current through them to produce ohmic heating, the shape memory metal actuators 75 shorten in length and so pull the rigid portion 66 upwardly away from the helmet to open an air vent, as shown in Fig. 8. This allows air 82 to vent from the inside to the outside of the helmet 95 via the fabric liner 60. The adhesive between the fabric liner 60 and the outer shell 62 does not extend over the region 80 between the points 70 and 71, allowing the rigid portion to pivot upwardly about the living hinge 68.

The shape memory metal actuators 75 may be controlled in just the same manner as the shape memory metal actuators 54 of the first embodiment.

In alternate embodiments, the fabric liner 60 could have apertures cut through it beneath the rigid portions 66 and 67, or be omitted entirely, to help improve airflow and evaporative cooling through the region 80.

Further alternative embodiments falling within the scope of the appended claims will also be apparent to the skilled person, for example alternate materials may be substituted for those described above.

Claims

1. A helmet comprising a plurality of air vents, and covers for opening and closing the air vents, wherein the covers are configured to hinge outwardly from the helmet to open the air vents. ^"

2. The helmet of claim 1 , wherein the helmet comprises an outer shell and a liner inside of the outer shell, and wherein the covers are configured to hinge outwardly from the liner.

3. The helmet of claim 2, wherein the covers are formed by portions of the outer shell that are configured to hinge away from the liner.

4. The helmet of claim 2 or 3, wherein the liner is configured to contact the head of a person wearing the helmet.

5. The helmet of claim 2, 3, or 4, wherein each cover is hingedly attached to a static portion of the outer shell.

6. The helmet of claim 5, wherein each cover is hingedly attached by a living hinge of the outer shell.

7. The helmet of any preceding claim, wherein the helmet comprises a support shell having apertures that form the air vents.

8. The helmet of claim 7 when appended to any one of claims 1 to 4, wherein the covers are hingedly attached to the support shell.

9. The helmet of any one of claims 7 and 8, when appended to at least claim 2, wherein the support shell is between the outer shell and the liner.

10. The helmet of any preceding claim, wherein the covers are configured to hinge outwardly from the helmet in directions that arc towards a front of the helmet.

11. The helmet of claim 10, wherein the helmet comprises a front portion configured to cover the front half of the top of a wearer's head and a rear portion configured to cover the rear half of the top of the wearer's head, and wherein all of the covers are positioned at the front portion.

12. The helmet of any preceding claim, wherein the covers form a tessellation with one another when the air vents are closed.

13. The helmet of any preceding claim, wherein the covers are controlled by solid state actuators to open and close the air vents.

14. The helmet of any preceding claim, wherein the helmet comprises an acoustic shot detector and a controller, the controller configured to control the covers to open and close the air vents based upon the acoustic shot detector.

15. The helmet of any preceding claim, wherein each cover is configured to hinge outwardly from the helmet about a hinge axis that is parallel to an exterior surface of the helmet adjacent the hinge axis.

16. A helmet substantially as described herein with reference to the accompanying drawings.