Helmet

Abstract

A helmet, which may be, for example, a sports helmet or a work safety helmet, includes a helmet body including a solid foam of expanded foam particles, where the solid foam has a varying hardness at least in some regions.

Description

Technical Field

[0001] This application relates to helmets, specifically sports helmets or work safety helmets. Background Art

[0002] Such helmets are used to protect the corresponding wearer of the helmet from head injuries in the case where the wearer falls or an object impacts the wearer's head. Depending on the application, the protective helmet can be used as and configured as a sports helmet or a work safety helmet, such as a bicycle helmet or a cycling helmet. In particular, when used as a bicycle helmet, the helmet can have one or more ventilation holes to support passive cooling of the wearer's head by ambient air or against the wind.

[0003] The helmet generally includes a helmet body having at least substantially (e.g., only separated from the ventilation openings) a concave inner portion and at least substantially a convex outer portion. The concave inner portion faces the head of the wearer of the helmet when the helmet is worn, and the convex outer portion is opposite to the concave inner portion. The helmet body is adapted in terms of shape, thickness, and material to absorb as much of the kinetic energy acting on the helmet during an impact (collision or strike) as possible through inelastic and / or elastic deformation. Such shock-absorbing properties can be particularly generated by a helmet body made of solid foam.

[0004] It is common practice to construct the helmet body by overmolding a pre-separately manufactured outer helmet shell according to the so-called in-mold technique. However, in principle, the helmet body can also be manufactured independently of the helmet shell as a molded body made of solid foam. In both cases, the solid foam is formed in this regard by expanding foam particles of a suitable material within a defined mold. The helmet body is generally entirely formed of solid foam. Thus, the helmet body can be relatively easily manufactured as a single molded part.

[0005] Generally, the molded part is then formed substantially uniformly such that different regions of the helmet body at least substantially have the same physical properties, particularly the same shock-absorbing properties. However, it may be advantageous if the helmet has different physical properties at different positions. Thus, for example, it is reasonable if the helmet body can be at least mainly relatively easily deformed and can largely plastically absorb as much kinetic energy as possible, but the helmet is still quite hard at its outer portion so as not to be damaged by minor impacts and rendered unusable. Additionally, it may be advantageous to provide: helmet regions that can be sheared relatively firmly, such as regions capable of absorbing torque; and other regions that are relatively rigid with respect to shear forces, for example, to ensure the stable structure of the helmet.

[0006] Providing different regions with different physical properties at the helmet is generally achieved by forming the helmet from a plurality of separately formed elements having different physical properties, wherein, depending on which property is desired in which region of the helmet, the corresponding elements are arranged in the corresponding regions.

[0007] For example, in order for the helmet to be rather hard at its outer side portion without the entire helmet body having to be correspondingly hard, the helmet may include a thin helmet shell formed separately from the helmet body, the thin helmet shell being made of a corresponding material (such as acrylonitrile butadiene styrene copolymer (ABS), polyethylene terephthalate (PET) or polycarbonate (PC)), provided at the outer side portion of the helmet body, and at least substantially completely covering the outer side portion of the helmet body. Alternatively, in order for the helmet body to have, for example, different shock-absorbing properties in the edge region and the central region, the helmet body may be formed in a plurality of parts, wherein the different parts are made of different materials having different shock-absorbing properties, and the plurality of parts are joined together after being separately manufactured to commonly form the helmet body.

[0008] However, for this purpose, the more components that have to be manufactured separately, and the more materials that have to be processed and / or processed in different ways, the more laborious the overall manufacture of the helmet. In addition, the recycling of helmets including many different materials is also more difficult. Summary of the Invention

[0009] The object of the present application is to provide a helmet of the above type, which is particularly suitable for various requirements, and can be manufactured with relatively little work, and is relatively easy to handle after use.

[0010] This object is achieved by a helmet having the features of claim 1. Advantageous embodiments of the present application result from the dependent claims, the present description and the drawings.

[0011] According to the present application, a helmet, in particular a sports helmet or a work safety helmet, includes a helmet body, which includes a solid foam of expanded foam particles. In this regard, the helmet body may have at least substantially a concave inner side portion and at least substantially a convex outer side portion, the inner side portion facing the head of the wearer of the helmet when the helmet is worn, and the outer side portion being opposite to the inner side portion.

[0012] Since the helmet body includes a solid foam, it can form a central shock-absorbing element of the helmet. The solid foam can generally be elastically deformable (to a certain extent). However, the solid foam is preferably a hard foam such that the solid foam is at least substantially only plastically deformable.

[0013] The foam is formed from expanded foam particles. These foam particles, which can at least substantially have a spherical shape, are small particles, in particular so-called foam beads or beads. The foam particles can be pre-expanded, i.e., they can already be formed as foam, for example, from microparticles or directly from a melt of a foamable material, in particular a polymer. In this regard, the foam particles initially have a relatively dense structure (small pores), and can cause expansion, in particular by providing heat.

[0014] If a defined space of a certain shape (e.g., a mold for manufacturing a helmet body) is at least mostly filled with such foam particles that have not (fully) expanded, and then the foam particles are expanded, they expand into the remaining intermediate space, in particular such that they ultimately occupy the entire space. Generally, the expanded foam particles press against each other in this regard, such that they adhere to each other, bond together, or even fuse. This is also because they temporarily lose their solid form and become soft during the expansion process.

[0015] In this regard, the foam particles can also at least partially melt, especially if heat is provided to them for expansion. Due to the expansion (and the softening or melting that occurs in the process), the foam particles preferably bond to each other in a material-bonded manner, in particular by at least partially fusing with each other. Then, the expanded foam particles (possibly after they have cooled down) form a continuous body of solid foam that has the shape of the defined space and, in this regard, serves as a mold for forming the solid foam.

[0016] The helmet body includes at least one such solid foam. The helmet body can generally also include a plurality of spatially demarcated solid foams, which may be manufactured separately from each other. In this regard, it can be provided that all of these foams are formed from expanded foam particles of the same material, or one or more of these foams are formed from expanded foam particles of a material different from one or more of the other materials of these foams.

[0017] However, the helmet body preferably includes only a single continuous solid foam. In particular, the helmet body can be formed from the solid foam.

[0018] In addition, in addition to the above-mentioned solid foam (and possibly other solid foams), the helmet body can generally also include other elements. For example, the helmet body can include an outer helmet layer and an inner helmet layer (and possibly even more helmet layers), where the outer helmet layer is closer to the outer side portion of the helmet body than the inner helmet layer, specifically includes the outer side portion, and the inner helmet layer is closer to the inner side portion of the helmet body than the outer helmet layer, specifically includes the inner side portion, and where only one of these helmet layers, specifically the outer helmet layer, includes the solid foam, specifically is formed from the solid foam.

[0019] However, the helmet body is preferably formed as a single piece. Thus, the helmet body does not include any other elements formed separately from the solid foam.

[0020] This does not exclusively mean that the solid foam is formed from expanded foam particles. On the contrary, the solid foam can consist of more than just expanded foam particles. For example, other particles, such as fibers for reinforcing the foam, can be embedded in the solid foam.

[0021] In this regard, any plastics of expandable foam particles and the molded parts produced therefrom can generally be considered. The helmet body can particularly include solid foams of expanded polystyrene (EPS), expanded polypropylene (EPP), expanded acrylonitrile-butadiene-styrene copolymer (EABS), expanded polycarbonate (EPC), expanded polyamide (EPA), expanded polybutylene terephthalate (EPBT), expanded polyethylene terephthalate (EPET), expanded modified polyphenylene ether (EmPPE), expanded thermoplastic polyurethane (ETPU), expanded polyoxymethylene (EPOM), expanded polymethyl methacrylate (EPMMA), and / or expanded polyether ketone (EPEK). The solid foam can also be formed from a mixture of foam particles of two or more of the said substances.

[0022] According to the present application, it is further provided that the solid foam has a varying hardness at least locally. The varying hardness can also be accompanied by a varying strength and / or stiffness of the solid foam.

[0023] Therefore, the helmet according to the present application is characterized in that the helmet body is not formed uniformly, especially in terms of the physical property of hardness, but is formed from a solid foam having a locally varying hardness. This makes it possible to individually adjust different regions of the helmet body according to the hardness of different regions of the helmet body to adapt to the requirements or desired properties present in the corresponding regions. In this way, the helmet body can also perform tasks performed by other elements of the helmet. Additionally, in this regard, the helmet body can be formed as a single piece and still have a wide range of properties as a whole, which would otherwise have to be distributed among multiple parts of the helmet body.

[0024] In this regard, solid foams can generally be produced in such a way that foam particles are expanded within a defined mold to form a molded body corresponding to the mold, wherein the varying hardness of the solid foam can be achieved by supplying heat to the foam particles with different intensities (quantity and / or speed) in different regions of the mold. In other words, the foam particles are heated more and / or faster in one or more regions of the mold than in one or more other regions of the mold. For this purpose, it is particularly advantageous to supply heat in the form of infrared radiation that can be controlled with a comparable spatial accuracy. For example, the solid foam can be prepared according to one of the methods described in WO2017 / 109079A1.

[0025] According to an advantageous embodiment, the solid foam is formed entirely of the same material or the same material composition. If the solid foam consists of multiple materials, it is thus formed of at least a substantially homogeneous mixture; if the solid foam includes only a single material, the material is in any case uniformly distributed. Thus, the fact that different regions of the solid foam have different hardnesses cannot be caused by different regions having different material compositions. Instead, the regionally varying hardness preferably (exclusively) results from the process of forming the solid foam, in particular from how the foam particles forming the solid foam expand in different ways in different regions, i.e., preferably (especially) by heating with the aid of infrared radiation, wherein heat is supplied to different regions with different intensities (see previous paragraph).

[0026] Since the solid foam has varying hardness at least locally, there are different regions in which the hardness of the solid foam differs from each other. In particular, the solid foam can at least include: a first region having a first hardness (overall); and a second region, different from the first region and having a second hardness (overall) different from the first hardness. In this regard, the hardness varies not only at the microscopic level, but it can be provided that the first region and the second region each extend at least 1 cm, preferably at least 2 cm, especially at least 3 cm in at least one (respective) spatial direction.

[0027] In this regard, the regions of different hardnesses (e.g., the first region and the second region) are preferably joined to each other in a material-bonded manner. In other words, the solid foam included in the helmet body is continuous in terms of material, even at the location where its hardness changes, i.e., the solid foam has no interruption in its material structure.

[0028] Conversely, the hardness does not necessarily have to vary continuously, but can also change suddenly (at least practically) between two regions of different hardness. This can in particular be the result of very different local thermal effects on different regions when forming the solid foam. A specific region in which the solid foam is formed within the mold can be heated particularly strongly, for example, compared to adjacent regions (and can thus differ particularly greatly from adjacent regions in terms of its hardness), because the foam particles in this region are heated using a heat transfer medium such as water or preferably geothermal oil for precise local temperature control of the foam particles or the mold.

[0029] According to another advantageous embodiment, the helmet body generally has a spherical shell shape (i.e., a part corresponding generally to a spherical shell, in particular the shape of a hemispherical shell), wherein the hardness of the solid foam varies in the radial direction with respect to the center of the spherical shell shape. The concave inner part of the helmet body further mentioned above can be oriented radially inwards in this regard, i.e., towards this center, while the convex outer part of the helmet body can be oriented radially outwards, i.e., away from this center. In this regard, the hardness of the solid foam can vary particularly in the radial direction because the solid foam has a different hardness in the radially inner region compared to the radially outer region (with respect to the radially inner region).

[0030] According to an advantageous further development, the hardness of the solid foam increases radially outwards and / or radially inwards. In other words, it can be advantageous, for example, for the hardness of the solid foam to increase from radially inwards to radially outwards, from radially outwards to radially inwards, or starting from the radially central region, to increase both radially outwards and radially inwards, in particular monotonically (possibly at least almost suddenly).

[0031] In particular, the solid foam can advantageously have: an outer surface layer that radially bounds (with respect to the center of the spherical shell shape) the helmet body; an inner surface layer that radially bounds the helmet body; and a core disposed between the outer surface layer and the inner surface layer, wherein the hardness of the outer surface layer and / or the inner surface layer is greater than the hardness of the core. In this regard, one or more additional layers and / or transition zones between different layers can be formed between the core and the outer surface layer and / or the inner surface layer. Since the solid foam has such a harder surface layer compared to the core of the solid foam, it can advantageously dispense with the provision of a separate helmet shell for protecting the helmet body on the corresponding side (outer part or inner part) of the helmet body.

[0032] According to another advantageous embodiment, the helmet body generally has a spherical shell shape (i.e., the shape of a part corresponding generally to a spherical shell, in particular a hemispherical shell, in particular with respect to the spherical shell shape described in the above embodiment), wherein the hardness of the solid foam varies in the tangential direction (i.e., rotating around the center M) with respect to the center of the spherical shell shape.

[0033] In particular, it may be advantageous for the hardness of the solid foam to be greater at the ends of the tangential extent of the helmet body than in the region between these ends. However, in principle, this can also be the opposite, such that the hardness of the solid foam at the ends of the tangential extent of the helmet body is less than the hardness of the solid foam in the region between these ends.

[0034] The ends of the tangential extent of the helmet body may in particular comprise or be formed by the circumferential edge of the helmet body. This edge may connect the outer side portion of the helmet body to the inner side portion of the helmet body and, in doing so, may extend once around the entire helmet body. In this regard, it is particularly advantageous for such an edge to have a different hardness, in particular a greater hardness, than the inner region of the helmet body (arranged within the edge and spaced apart from the ends of the tangential extent of the helmet body), which inner region of the helmet body may correspond to the core.

[0035] If the helmet has ventilation holes that also extend through the helmet body, then it is more advantageous for the helmet body to have a different hardness, in particular a greater hardness, in the region adjacent to the ventilation holes (which may include the edges of the ventilation holes), in particular the region surrounding them, than in regions further away from the ventilation holes, such as the core of the helmet body.

[0036] In particular, it is advantageous for the hardness of the solid foam to vary in both the radial and tangential directions with respect to the center of the spherical shell shape, wherein the hardness of the solid foam in the outer surface layer and the inner surface layer and at the ends of the tangential extent of the helmet body is, for example, greater than the hardness in the region between them, in particular greater than the hardness of the core. In this way, the helmet body can mainly have an outward solid shell while having a core optimized with respect to maximum possible shock absorption, without having to form multiple parts or being formed of multiple different materials for this purpose. Description of the Drawings

[0037] The present application will be further explained below only by way of example with reference to the drawings showing a cross-sectional view of an embodiment of a helmet according to the present application.

[0038] Figure 1 The helmet 11 of the illustrated embodiment is a bicycle helmet, which is shown in a highly simplified cross-sectional view. In particular, in Figure 1 only the helmet body 13 of the helmet 11 is shown, wherein the helmet 11 may also include additional elements, such as straps for fastening, pads for a comfortable fit on the head of the respective wearer, and the like. Detailed Description

[0039] The helmet body 13 generally has a spherical shell shape and thus has a concave inner portion 15 and a convex outer portion 17. In this regard, the helmet 11 is configured to be placed on the head of a wearer, wherein the inner portion 15 of the helmet body 13 faces or contacts the head, and the outer portion 17 of the helmet body 13 faces away from the head. The helmet 11 also has a plurality of ventilation holes 29, each ventilation hole 29 extending through the helmet body 13 in a generally radial direction (relative to the center of the spherical shell shape).

[0040] The helmet body 13 includes a solid foam 19. The helmet body 13 is particularly formed by the solid foam 19. According to the present application, in this regard, the solid foam 19 has a hardness that varies at least locally.

[0041] In the illustrated embodiment, the hardness of the solid foam 19 particularly varies because the solid foam has an outer surface layer 21, an inner surface layer 23, and a core portion 25, and the hardness of the outer surface layer 21 and the inner surface layer 23 is greater than the hardness of the core portion 25. The outer surface layer 21 radially outwardly defines the helmet body 13 (relative to the center of the spherical shell shape), while the inner surface layer 23 radially inwardly defines the helmet body 13. The core portion 25 is disposed between the outer surface layer 21 and the inner surface layer 23.

[0042] Due to this configuration, the hardness of the solid foam 19 varies in the radial direction. Additionally, the hardness of the solid foam 19 also varies in the tangential direction. This is because the hardness of the solid foam 19 is greater at the ends of the tangential extent of the helmet body 13 that form the circumferential edge 27 of the helmet body 13 than in the region between these ends, particularly greater than the hardness of the core portion 25 of the helmet body 13.

[0043] Furthermore, the tangential extent of the helmet body 13 is also interrupted by the ventilation holes 29. In this regard, in each case, the solid foam 19 also has a greater hardness in the region of the circumferential edge 27' of each ventilation opening 29 than in the region remote from the ventilation holes 29, particularly greater than the hardness of the core portion 25 of the helmet body 13. In this regard, these regions of different hardness (surface layers 21, 23, core portion 25, and circumferential edges 27, 27') are not mutually separated parts of the helmet body 13, but are advantageously composed of the same material and are joined to each other in a material-bonded manner such that the helmet body 13 is integrally formed as a single piece.

[0044] In the illustrated embodiment, the outer surface layer 21, the inner surface layer 23, the circumferential edge 27 of the helmet body 13, and the circumferential edge 27' of the ventilation hole 29 each have the same hardness greater than the hardness of the core 25 of the helmet body 13. Additionally, in each case, the circumferential edges 27, 27' connect the outer surface layer 21 and the inner surface layer 23 to each other and, in so doing, seamlessly merge into the respective surface layer 21 or 23. Thus, the surface layers 21, 23 and the circumferential edges 27, 27' together form the entire surface layer of the helmet body 13, which completely surrounds the core 25 of the helmet body 13 and thus defines the helmet body 13 outwardly.

[0045] In this way, the helmet body 13 can have a hardness in its core 25 that is suitable for absorbing large impacts well, such as may occur during a fall, and the helmet body 13 can simultaneously have a greater hardness at its surface compared to the core, thereby protecting the helmet body 13 from minor damage during normal use of the helmet 11. Additionally, the core 25 does not necessarily have to have the same hardness throughout. Instead, one or more parts of the core 25 can have a different hardness from the rest of the core 25, and / or one or more other regions of the helmet body 13 that are different from the core 25 can have a different hardness from the core 25. As a result, for example, the helmet body 13, particularly the core 25 of the helmet body 13, can have different shock-absorbing characteristics at different locations, each of which is particularly suitable for the type of impact that typically occurs at the respective location in the event of an impact or collision.

[0046] Thus, due to the embodiment according to the present application, the helmet 11 can provide particularly reliable protection. In this regard, although different regions of the helmet 11 have different shock-absorbing characteristics, the helmet body 13 does not have to be formed from multiple separate components, and thus the helmet body 13 can be manufactured with relatively little effort simultaneously.

[0047] Description of reference numerals

[0048] 11 Helmet

[0049] 13 Helmet body

[0050] 15 Inner part

[0051] 17 Outer part

[0052] 19 Solid foam

[0053] 21 Outer surface layer

[0054] 23 Inner surface layer

[0055] 25 Core

[0056] 27, 27' Circumferential edge

[0057] 29 Vent

Claims

1. A helmet (11), comprising a helmet body (13), the helmet body (13) comprising a solid foam (19) of expanded foam particles, Among them, The solid foam (19) has a varying hardness at least locally.

2. The helmet according to claim 1, wherein, The solid foam (19) is integrally formed of the same material or the same material composition.

3. The helmet according to claim 1, wherein, Regions of different hardness are fused to each other in a material-bonded manner.

4. The helmet according to claim 1, wherein, The helmet body (13) generally has a spherical shell shape, and wherein the hardness of the solid foam (19) varies in the radial direction with respect to the center of the spherical shell shape.

5. The helmet according to claim 4, wherein, The hardness of the solid foam (19) increases radially outward and / or radially inward.

6. The helmet according to claim 4, wherein, The solid foam (19) has: an outer surface layer (21) that radially outwardly defines the helmet body (13); an inner surface layer (23) that radially inwardly defines the helmet body (13); and a core (25) disposed between the outer surface layer (21) and the inner surface layer (23), and wherein at least one of the hardness of the outer surface layer (21) and the hardness of the inner surface layer (23) is greater than the hardness of the core (25).

7. The helmet according to claim 1, wherein, The helmet body (13) generally has a spherical shell shape, and wherein the hardness of the solid foam (19) varies in the tangential direction with respect to the center of the spherical shell shape.

8. The helmet according to claim 7, wherein, The hardness of the solid foam (19) at the ends (27, 27') of the tangential range of the helmet body (13) is greater than the hardness in the region between the ends (27, 27').

9. The helmet according to claim 7, wherein, The hardness of the solid foam (19) at the ends (27, 27') of the tangential range of the helmet body (13) is less than the hardness in the region between the ends (27, 27').

10. The helmet according to claim 1, wherein, The helmet (11) is configured as a sports helmet or a work safety helmet.

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