Helmet with sliding facilitator

Description

EP3231306 B1

Technical Field The present invention relates generally to a helmet comprising an energy absorbing layer, with or without an outer shell, a material or mesh cap and a slip aid.

Background of the Invention [0002] To prevent or reduce trauma to the skull and brain, many activities require helmets. Helmets usually consist of an outer shell, usually made of plastic or composite material, and an energy-absorbing layer called padding. Currently, the protective helmet must be designed to meet specific legal requirements regarding, among others maximum acceleration that can occur in the center of gravity of the brain at a certain load. Usually tests are carried out on so-called the manikin's skull with a helmet on, which is subjected to radial impacts towards the head. This led to the fact that modern helmets have a good ability to absorb energy in the case of radial impacts on the skull, while the absorption of energy in other load directions is not so optimal.

[0003] In the event of a radial impact, the head will be accelerated by a translational movement, which causes linear acceleration. Translational acceleration can lead to skull fractures and / or traumatic brain injury due to friction or pressure. However, according to injury statistics, pure radial impacts are rare.

[0004] On the other hand, clean tangential impact that results in pure angular acceleration of the head is also rare.

[0005] The most common type of impact is an oblique impact, which is a combination of radial and tangential force acting on the head simultaneously, e.g. causing concussion. The oblique impact causes both translational acceleration and rotational acceleration of the brain. Rotational acceleration causes the brain to rotate in the skull, leading to bodily injuries to the elements connecting the brain to the skull, as well as to the injuries of the brain itself.

[0006] Examples of rotational injuries are on the one hand shock, subdural hematomas (SDH), bleeding due to rupture of blood vessels, and on the other hand diffuse axonal damage (DAI), which can be summarized as excessive stretching of nerve fibers due to deformation due to shear stress in brain tissue. Depending on the rotational force parameters, such as duration, amplitude and growth rate, SDH or DAI, or a combination of these may occur. In general, SDH is formed in the case of short duration and high amplitude, and DAI in the case of longer and more widespread loads due to acceleration. It is important that these phenomena are taken into account, which will ensure good skull and brain protection.

[0007] The head has natural protective systems that try to suppress these forces with the help of the scalp, hard skull and cerebrospinal fluid underneath it. During an impact, the scalp and cerebrospinal fluid act as a rotational shock absorber, both by squeezing and sliding the skull. Most of today's helmets do not provide protection against rotational injuries.

[0008] Good ventilation and aerodynamic shape are important features of e.g. bicycle, riding and ski helmets. Modern bicycle helmets are usually of the in-mold type, manufactured by enclosing a thin, rigid shell during the molding process. This technology allows for more complex shapes than hard shell helmets, as well as larger ventilation openings.

[0009] EP 0 954 993 discloses a helmet comprising an energy absorbing layer and a material cap for attachment to the user's head. US 6,658,671, US 2004/0117896 and US 2001/032351 disclose helmets with slip layers between the inner and outer shells.

Summary [0010] A helmet is disclosed comprising an energy absorbing layer and a slip aid contained within the energy absorbing layer.

[0011] According to the invention, the helmet comprises an energy absorbing layer, a material or mesh cap intended for attachment to the user's head, and a slip aid, wherein the slip aid is attached to the hat or the cap is adapted to act as a slip aid and the assistive slip is configured to allow slip during the impact between the energy absorbing layer and the cap.

[0012] Preferably, an outer shell is provided outside the energy absorbing layer. A helmet designed in accordance with this can be made using inmould technology, although it is possible to apply the disclosed idea to all types of helmets, e.g. hard shell helmets, such as motorcycle helmets.

[0013] According to yet another embodiment, the cap is attached to the energy absorbing layer and / or the outer shell by means of at least one fastening element which can be adapted to absorb energy and forces by elastic, semi-elastic or plastic deformation. During an impact, the energy absorbing layer acts as an impact absorber by compressing the energy absorbing layer, and if an outer shell is used, it will distribute the impact energy into the shell. The slip aid allows slip between the cap and the energy absorbing layer, enabling a controlled way to absorb rotational energy that would otherwise be transmitted to the brain. Rotational energy can be absorbed as friction heat, deformation of the energy absorbing layer or deformation or displacement of at least one fastening element. The absorbed rotational energy will reduce the amount of rotational acceleration acting on the brain, thereby reducing the rotation of the brain in the skull.

[0014] The fastening element may comprise at least one suspension element having first and second parts. The first part of the suspension element can be adapted to be attached to the energy absorbing layer, and the second part of the suspension element can be adapted to be attached to the cap.

[0015] The slip aid provides the possibility of sliding movement in any direction. It is not limited to movements around certain axes.

[0016] It should be noted that each embodiment or part of an embodiment can be combined in any way, but the scope of the invention is defined by the claims.

Brief Description of the Drawings [0017] The invention has now been described by way of example with reference to the attached drawings, in which:

Fig. 1 is a cross-sectional view of the helmet useful for understanding the invention, Fig. 2 is a cross-sectional view of the helmet useful for understanding the invention, placed on the user's head, Fig. 3 is a helmet positioned on the user's head when receiving a frontal impact. Figure 4 shows the helmet positioned on the user's head while receiving a frontal impact, Figure 5 shows the attachment device in more detail, Figure 6 shows the fastener, Figure 7 shows the fastener, Figure 8 shows the fastener, Figure 9 shows the fastener, Figure 10 shows the fastener, Figure 11 shows the fastener, Figure 12 shows the fastener, Figure 13 shows the fastener, Fig. 14 shows the fastener, Fig. 15 shows the fastener, Fig. 16 shows the test results table, Fig. 17 shows the test results chart and Fig. 18 shows the test results chart.

Detailed description [0018] The following is a detailed description. It should be noted that the figures are for reference only and do not limit the scope in any way. Thus, all references to directions, such as "up" or "down", refer only to the directions shown in the figures.

[0019] A protective helmet useful for understanding the invention comprises an energy absorbing layer and a slip aid provided within the energy absorbing layer. According to one embodiment, an in-mold helmet suitable for cycling is provided. The helmet consists of an outer, preferably thin, rigid shell made of a polymer material such as polycarbonate, ABS, PVC, fiberglass, Aramid, Twaron, carbon fiber or Kevlar. It is also possible to skip the outer shell. On the inside of the shell there is an energy absorbing layer that can be a polymer foam material, such as EPS (foamed polystyrene), EPP (foamed polypropylene), EPU (foamed polyurethane) or other structures such as e.g. honeycomb. The slip aid is provided inside the energy absorbing layer and is adapted to slip relative to the energy absorbing layer or relative to the attachment device which is provided to attach the helmet to the user's head. The fastening device is attached to the energy absorbing layer and / or shell by means of fastening elements adapted to absorb impact forces and energy.

[0020] The slip aid may be a low friction material or may be covered with a low friction material: examples of possible materials are PTFE, ABS,

PVC, PC, Nylon, textile materials. It is conceivable that slippage is possible due to the structure of the material, e.g. due to a material with a fiber structure such that the fibers slide relative to each other. [0021] During an impact, the energy absorbing layer acts as an impact absorber by compressing the energy absorbing layer, and if an outer shell is used, it will distribute the impact energy into the energy absorbing layer. The slip aid allows slip between the fastening device and the energy absorbing layer, enabling a controlled manner of absorbing rotational energy that would otherwise be transmitted to the brain. Rotational energy can be absorbed as friction heat, deformation of the energy absorbing layer or deformation, or offset of at least one attachment element. The absorbed rotational energy will reduce the amount of rotational acceleration acting on the brain, thereby reducing the rotation of the brain in the skull. This reduces the risk of rotational injuries such as subdural hemorrhage, SDH, vascular rupture, shock and DAI.

[0022] Fig. 1.shows a helmet useful for understanding the invention, where the helmet comprises an energy absorbing layer 2. The outer surface 1 of the energy absorbing layer 2 can be made of the same material as the energy absorbing layer 2 or the outer surface 1 can also be rigid shell 1 made of a material other than an energy absorbing layer

2. Inside the energy absorbing layer 2, a slip aid is provided in relation to the attachment device 3 intended to attach the helmet to the user's head. According to the helmet shown in Fig. 1. the slip aid 5 is attached to or integrated into the energy absorbing layer 2, although the slip aid 5 may equally well be provided on or integrated with the fastening device 3, thereby providing the possibility of slip between the energy absorbing layer 2 and the fastening device 3. The helmet of Fig. 1. has a plurality of ventilation holes 17 for allowing air to pass through the helmet [0023] The attachment device 3 is attached to the energy absorbing layer 2 and / or the outer shell 1 by means of four attachment elements 4a, 4b, 4c and 4d adapted to absorb energy by deformation in a manner elastic, semi-elastic or plastic. Energy can also be absorbed by friction with heat generation and / or deformation of the mounting device or any other part of the helmet. According to the helmet shown in Fig. 1. the four attachment elements 4a, 4b, 4c and 4d are suspension elements 4a, 4b, 4c, 4d having first and second parts 8, 9, the first parts 8 of suspension elements 4a, 4b, 4c, 4d are adapted to be attached to the device 3 and the second parts 9 of the suspension elements 4a, 4b, 4c, 4d are adapted to be attached to the energy absorbing layer 2.

[0024] The slip aid 5 may be a low friction material which in the helmet shown is delivered to the outside of the attachment device 3 as facing the energy absorbing layer 2, although in other helmets it is just as conceivable that the slip aid 5 is provided inside on the inside of the energy absorbing layer 2. The low friction material may be a wax polymer such as PTFE, PFA, FEP, PE and UHMWPE, or a powder material that can be fed with a lubricant. Such a low friction material can be applied to one or both of the slip promoter and the energy absorbing layer, and in some helmets the energy absorbing layer itself is adapted to act as a slip promoter and may contain low friction material.

[0025] The fastening device may be made of a resilient or semi-elastic polymeric material, such as PC, ABS, PVC or PTFE, or a natural fibrous material, such as cotton fabric. According to the invention, the attachment device is a material or mesh cap. The cap can be fitted with slip aids, such as patches of low friction material. In some embodiments, the attachment device itself is adapted to act as a slip aid and may include low friction material. Fig. 1 further discloses an adjustment device 6 for adjusting the diameter of the headband for a specific user. In other helmets, the headband may be a flexible headband, in which case the adjustment device 6 can be excluded.

[0026] Fig. 2. shows the helmet similar to the helmet of Fig. 1 when placed on the user's head. However, in Fig. 2. the fastening device 3 is attached to the energy absorbing layer by means of only two fastening elements 4a, b adapted to absorb forces and energy in an elastic, semi-elastic or plastic way. The helmet of Fig. 2 comprises a hard outer shell 1 made of a material other than an energy absorbing layer 2.

[0027] Fig. 3. shows the helmet of Fig. 2, when it receives a frontal oblique impact I creating a rotational force acting on the helmet causing the energy absorbing layer 2 to slide against the mounting device 3. The mounting device 3 is attached to the energy absorbing layer 2 by using fasteners 4a, 4b. The attachment absorbs rotational forces through elastic or semi-elastic deformation.

[0028] Fig. 4. shows the helmet of Fig. 2. when it receives a frontal oblique impact I creating a rotational force acting on the helmet causing the energy absorbing layer 2 to slide against the mounting device 3. The mounting device 3 is attached to the energy absorbing layer by means of tear fasteners 4a, 4b that absorb rotational energy through plastic deformation and thus require replacement after impact. The combination of Fig. 3 is very possible. and Fig. 4, i.e. a part of the fastening elements tears, absorbing energy in a plastic way, while another part of the fastening elements deforms and absorbs forces in a resilient manner. In combined systems it is possible that only the plastically deformable part needs to be replaced after the impact.

[0029] The upper part of Fig. 5. shows the outer side of the attachment device 3, where the attachment device 3 comprises a headband 3a adapted to surround the head of the user, a longitudinal band 3b reaching from the forehead to the back of the user's head and attached to the headband 3a and the band transverse 3c extending from the left side of the user's head to the right side of the user's head and attached to the headband 3a. Elements or parts of the attachment device 3 may be provided with slipping aids. The material of the fastening device may itself act as a slip aid. It is also possible to provide the fixing device 3 with added material with a low coefficient of friction.

[0030] Fig. 5. furthermore shows four fastening elements 4a, 4b, 4c, 4d attached to the fastening device 3. The fastening device 3 can only be a headband 3a or any other design acting as a fastening device for fastening on the user's head. In embodiments of the invention, the attachment device may be an entire cap adapted to completely cover the top of the user's head.

[0031] The lower part of Fig. 5. shows the inside of the attachment device 3, revealing an adjustment device 6 for adjusting the diameter of the headband 3a for a particular user. In other arrangements, the headband 3a may be a flexible headband, in which case the adjustment device 6 may be excluded.

[0032] Fig. 6. shows an alternative attachment element 4, in which the first part 8 of the attachment element 4 is attached to the attachment device 3 and the second part 9 of the attachment device 4 is attached to the energy absorbing layer 2 by means of an adhesive. The fastener 4 is adapted to absorb energy and impact force by deforming in an elastic, semi-elastic or plastic manner.

[0033] Fig. 7. shows an alternative attachment element 4, in which the first part 8 of the attachment element 4 is attached to the attachment device 3 and the second part 9 of the attachment device 4 is attached to the energy absorbing layer 2 by means of mechanical attachment elements 10 material of the energy absorbing layer 2.

[0034] Fig. 8. shows an alternative attachment element 4, in which the first part 8 of the attachment element 4 is attached to the attachment device 3 and the second part 9 of the attachment device 4 is attached to the interior of the energy absorbing layer 2, e.g. by forming the attachment device inside the energy absorbing layer material 2.

[0035] Fig. 9. shows the fastener 4 in section view and AA view. The fastening device 3 is attached to the energy-absorbing layer 2 by means of a fastening element 4 having a second part 9 arranged in a female part 12 adapted for elastic, semi-elastic or plastic deformation and the first part 8 connected to the fastening device 3. The female part 12 includes flanges 13 adapted to flex or deform elastic, semi-elastic or plastic when they are subjected to sufficiently high stresses from the fastening element 4, so that the second part 9 can leave the female part 12.

[0036] Fig. 10. shows an alternative fastening element 4 in which the first part 8 of the fastening element 4 is attached to the fastening device 3 and the second part 9 of the fastening device 4 is attached to the inside of the shell 1 through the entire energy absorbing layer 2. to do this e.g. by forming the fastening device 4 inside the material of the energy absorbing layer 2. It is also possible to insert the fastening device 4 through a hole in the shell 1 from the outside of the helmet (not shown).

[0037] Fig. 11. shows a helmet in which the attachment device 3 is attached to the energy absorbing layer 2 at its periphery by means of a membrane or sealing foam 24, which can be elastic or adapted to plastic deformation.

[0038] Fig. 12 shows a helmet where the attachment device 3 is attached to the energy absorbing layer 2 by means of a mechanical attachment element comprising mechanical coupling elements 29, with a self-locking function similar to the function of a self-locking drawstring 4.

[0039] Fig. 13 shows a helmet in which the fastener is a combined sandwich layer 27, such as a sandwich fabric, which may comprise elastically, semi-elastically or plastically deformable fibers connecting the fastening device 3 to the energy absorbing layer 2 and adapted to shear them by applying shear forces to them and thus to absorb rotational forces and energy.

[0040] Fig. 14. shows a helmet in which the fastening element comprises a magnetic fastening element 30, which may comprise two magnets with attractive forces, such as hypermagnetics, or one part containing a magnet and one part containing a magnetically attracted material, such as iron.

[0041] Fig. 15. shows a helmet in which the fastening element can be repeatedly fastened by means of the elastic male part 28 and / or the elastic female part 12 removably attached (so-called snap fastening) so that the male part 28 detaches from the female part 12 when a sufficiently high stress is applied to the helmet, in the event of impact, and the male part 28 can be reintroduced into the female part 12 to provide functionality again. It is also possible to snap fastening the fastener without disconnecting it at sufficiently high tension and without reattaching.

[0042] In the embodiments disclosed here, it is further more conceivable that the fastening elements are hyperelastic, such that the material absorbs energy elastically, but at the same time partly deforms plastically without complete damage.

[0043] In embodiments comprising a plurality of fasteners, it is furthermore more possible that one of the fasteners is the main fastener adapted to plastic deformation under the effect of a sufficiently high stress, while the additional fasteners are adapted to purely elastic deformation.

[0044] Fig. 16 is a table obtained from a test carried out with a helmet having a slip aid (MIPS), with respect to a normal helmet (Original) without a slip layer between the fixing device and the energy absorbing layer. The test was performed using a free falling instrumented head of the manikin, which strikes horizontally moving steel plates. The oblique impact causes a combination of translational and rotational acceleration, which provides greater realism than typical test methods in which helmets are dropped on a horizontal impact surface, achieving a pure vertical impact. Speeds up to 10 m / s (36 km / h) can be achieved in both the horizontal and vertical directions. The dummy's head has a system of nine accelerometers mounted to measure translational accelerations and rotational accelerations around all axes. In the current test, helmets are dropped from 0.7 meters. This results in a vertical speed of 3.7 m / s. The horizontal speed was chosen to 6.7 m / s, which leads to an impact speed of 7.7 m / s (27.7 km / h) and an impact angle of 29 degrees.

[0045] The test reveals a decrease in translational acceleration transmitted to the head and a large reduction in rotational acceleration transmitted to the head and the rotational speed of the head.

[0046] Fig. 17. is a graph of rotational acceleration over time for helmets having slip aids (MIPS_350, MIPS_352) relative to ordinary helmets (Org_349, Org_351) without slip layers between the mounting device and the manikin's head.

[0047] Fig. 18 is a graph of translational acceleration over time for helmets having a slip aid (MIPS_350, MIPS_352) versus ordinary helmets (Org_349, Org_351) without slip layers between the mounting device and the manikin's head.