US20210282490A1

US20210282490A1 - Impact protection structure

Info

Publication number: US20210282490A1
Application number: US17/263,436
Authority: US
Inventors: Patrick Pedevilla
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-07-26
Filing date: 2019-07-26
Publication date: 2021-09-16
Also published as: EP3826501A1; CA3107658A1; WO2020021063A1

Abstract

The invention relates to an impact protection structure, in particular for a helmet, to absorb kinetic energy during an impact, in particular a fall, comprising a plurality of cells arranged next to one another, wherein each cell has a hollow interior (1), which is delimited by at least one side wall (2), wherein cells adjoining one another have at least one common side wall (2), wherein the interior (1) and the side walls (2) run from an outer side (3) of the impact protection structure to an inner side (4) of the impact protection structure opposing the outer side (3), wherein at least one side wall (2) of a cell has at least one recess (5).

Description

The invention relates to an impact protection structure according to the preamble of claim 1 and to an impact protector according to claim 15.
The technical field of the invention includes mechanical structures for reducing the risk of deformation and injury to bodies of all types, including in particular also animal and human bodies, if they collide with other bodies and therefore in particular all types of protectors, including in particular helmets.
In the case of impact of solid bodies on other solid bodies, such as e.g. the impact of a human body on a solid obstacle, but for instance also in the case of impact of two inanimate bodies on one another (e.g. bumpers on concrete wall), there is a “release” of (kinetic) energy. This energy is, in this case, transferred, depending on elasticity or plasticity of the bodies, either as kinetic energy from one body to the other body, whereby the first body is decelerated and the second body is accelerated accordingly or the kinetic energy is converted by flexing and structure destruction work into heat. In reality, hybrids of the two mentioned principles only occur in each case in particular as a function of the mechanical and other physical properties of the two bodies, their relative arrangement in relation to one another and the environmental conditions such that when two moving bodies collide, a certain part of the original kinetic energy is always passed on and at the same time another part of the original kinetic energy is converted into heat energy, e.g. the pushing away and simultaneous deformation of vehicles in the case of a vehicle collision. The relationship between both conversion forms can be very different depending on the materials used and constructions of the mechanical structures in question.
When the kinetic energy of a body is converted, whether it be predominantly into the kinetic energy of another body, or predominantly into heat energy, kinetic energy is withdrawn from the first body. The withdrawal of kinetic energy of a moving body is equivalent to deceleration or a negative acceleration of this body. In this case, the integral of the negative acceleration of the mass of this body over time corresponds to the quantity of (withdrawn kinetic) energy.
From this follows that the same quantity of kinetic energy both in a longer-lasting process can be withdrawn with comparatively low maximum negative acceleration and in a comparatively shorter-lasting process with higher negative acceleration.
Depending on the structure of the body, from which kinetic energy is withdrawn, if certain maximum acceleration values (always caused by corresponding force influences) are exceeded, there may be irreversible deformations, such as e.g. an irreversible, fully or partially plastic deformation (e.g. crumple zone) or even breakage of a structure (e.g. bone breakage). To prevent such irreversible deformations, it is therefore desirable to withdraw from the body in question its kinetic energy in a comparatively long-lasting process or “to slowly decelerate” this body. The “slow deceleration” can be achieved by a corresponding extension of the brake path in the case of (in principle) unlimited space. In the case of a limited brake path (such as in particular mechanical protection structures, such as crumple zones, bumpers or even helmets), keeping the curve of the negative acceleration as flat and broad as possible, in contrast, remains the only option, with the integral of the (negative) acceleration of the body over time, i.e. the area below the acceleration curve must correspond (with the x-axis corresponding to t in secs and the y-axis to g in m/sec²) to the available kinetic energy of the first body decreased (or rather converted into heat energy) during the “brake process”.
Ultimately, all protective structures, such as e.g. impact protection mechanisms, airbags, but also helmets and other protectors serve the purpose of extending the break path and as a result keeping the maximum acceleration values low. In the case of the impact of an (unprotected) head on a solid obstacle, the delay process only begins upon contact of the skull with the obstacle. Since the “break path” in this case is extremely short, namely only a few millimeters by which the skull can be deformed, clearly extreme load peak must occur in this case. In the case of a head protected with a helmet, the “brake phase”, in contrast, begins much earlier, namely when the outer shell of the helmet contacts the obstacle. During the actual “brake process”, the entire helmet structure is compressed over up to a number of centimeters. In this case, the structure of the helmet is, in general, traditionally, selectively destroyed by deformation, whereby the kinetic energy is ultimately as a whole converted into heat energy by way of plastic deformation. The quality of a helmet structure is reflected in this case in particular in how low, in the case of standardized framework parameters, the loading peak is (EN 1077, EN 1078). In this case, the following applies: the steeper the flank is when increasing the negative acceleration at the beginning of the “brake process”, the broader and flatter the acceleration curve is during the “brake process” and ultimately the steeper the flank is when decreasing the negative acceleration at the end of the “brake process”, the lower the maximum acceleration and therefore the risk of plastic deformation or a breakage occurring to the protected body itself.
Different helmets are known from the prior art. WO 2017/046757 shows for example an impact protection structure for a helmet, with the structure consisting of a number of polyhedric cells arranged next to one another, which are connected by an elastic arc element.
Prior art in the case of protectors, in particular helmets, are mechanical structures, which are predominately manufactured from plastics and which deform in general largely plastically until breakage upon impact. The essential mechanical damping effects of these structures generally result from their material, which e.g. in the case of bicycle helmets are primarily polystyrene and/or its derivatives. The average loading peak achievable with such structures are in conventional bicycle helmets with the mentioned standardized impact settings currently around 175 g (Folksam study).
In addition, there are also already protection structures, which consist of pure, integral polygonal wall structures. However, they are not constructed from such materials, which do not behave predominantly elastically, such that in the case of an impact plastic deformations can occur. Furthermore, these structures have a high starting rigidity such that the structure only begins to deform and therefore convert kinetic energy into heat energy when a relative high loading limit is reached. If this loading limit is, however, reached, then the structure collapses on itself comparatively quickly such that the “energy decrease effect” is suboptimal and the loading peaks remain comparatively high and therefore represent a very high to lethal CCI risk for humans.
Conventional mechanical protection structures have substantially four crucial problems:
1. Even with the best conventional protector technologies, average loading peaks of still 175 g occur in the case of the prescribed impact test settings of bicycle helmets (EN 1078). In this case, it must be noted that in the case of loading peaks of 100 g to 150 g, moderate concussions occur, from 150 g to 200 g, serious concussions, from 200 to 250 g severe concussions and over 250 g lethal injuries can occur. Only in the case of loading peaks of below 100 g are clinically relevant concussions not assumed.
2. Conventional protection (helmet) structures are generally destroyed by an average to severe impact such that, in the case of a subsequent second impact (car-ground) they have only a significantly reduced or no protective effect at all. This is in particular problematic when it concerns a so-called “multi-impact accident”, in which e.g. a cyclist is firstly hit by a motor vehicle and is then hurled against a curb. It may happen here that the helmet no longer offers protection in the case of impact on the curb because its structure has already converted so much kinetic energy during the first impact on the vehicle that the helmet structure is broken such that it no longer develops any protective effect during the second impact.
3. In the case of conventional polystyrene helmets, when treated very carelessly, e.g. fall onto asphalt from >1 m, microcracks in the structure may result which are not discernible to the user. These microcracks then form the core of a break point which opens suddenly in the case of a subsequent impact and significantly reduces the protection level of the helmet, through to its complete failure. The main problem of such microcracks is that they develop very easily, but at the same time cannot be discovered, before, in the event of a fall, it is too late.
The object of the invention is therefore to provide an impact protection structure which has a high protective effect, in particular when damage to the structure results from an impact or fall, with the impact protection structure also in particular having a high wearing comfort.
This object is achieved by the characterizing feature of claim 1.
For an impact protection structure, in particular, for a helmet, to absorb kinetic energy during an impact, in particular a fall, comprising a plurality of cells arranged next to one another, with each cell having a hollow interior, which is delimited by at least one side wall, with cells adjoining one another having at least one common side wall, with the interior and the side walls running from an outer side of the impact protection structure to an inner side of the impact protection structure opposite the outer side, it is provided according to the invention that at least one side wall of a cell has at least one recess.
The recess enables in the case of an impact a reversible deformation of the structure, which extends the brake path such that the impact can be better absorbed. Furthermore, the recess serves as a target bend point and therefore leads to a selective static weakening of the structure such that the structure is destroyed in a controlled manner. As a result, it can be achieved that even in the case of a collapse of the structure, the tolerance range of the forces transferred to the body to be protected is not exceeded.
Due to the recesses, the use of particularly weather-resistant materials is also possible, which, without a recess, do not have adequate damping properties and therefore have hitherto not been used for impact protection structures. In addition, the recess enables an improved ventilation and a lighter weight such that an improved wearing comfort is achieved.
The height of the impact protection structure, i.e. the distance between outer side and inner side is specified by the height of the side walls. The inner side of the impact protection structure is preferably arranged facing a body to be protected, the outer side on the side facing away from the body to be protected. The circumference of the interior is determined by the length of the side wall or walls that delimit it. The interior can be polygonal, oval or round. The shape of the interior of a cell can change from the outer side to the inner side of the impact protection structure. The interior of a cell can therefore have on the outer side for example a hexagonal cross-section and on the inner side a rectangular cross-section
A first aspect of the invention has, as its subject matter, a mechanical structure made of materials with predominantly elastic properties, in which walls substantially in the form of polygonal and/or round and/or oval prisms, or also called extruded polygons, are joined together, with the walls being oriented substantially perpendicularly to the top surface of the body to be protected and at certain points can have recesses and/or thinned portions of the wall thickness, resulting in the walls of the structure beginning to fold in, during a force effect, in the desired manner such that the structure is as a result neither too rigid nor too soft for the purpose of impact damping. Due to the flexing work associated with the folding-in of the walls, mechanical energy input into the structure through the force effect is converted into heat energy and in this respect the kinetic energy of the colliding body increases comparatively gently over a comparatively large reduction path or a comparatively large reduction period such that loading peaks are notably reduced, which in particular for helmets during force effects in the standard range results in moderate and severe health impairments, in particular CCI of the wearer, can be avoided.
A polyhedron is a round, closed, multi-surface body. A polygonal body, in contrast, is an extruded polygon, as in particular in the case of the hexagonal structure here.
The second aspect of the invention has, as its subject matter, a particular shape of the part of structure which contacts the body to be protected, with the contact surface of the structure on the body to be protected being increased by correspondingly formed contact surfaces at the (lower) edges of the walls closer to the body to be protected such that the specific pressure is reduced by the force transfer from the structure to the body to be protected (N/cm²).
In the case of comparatively narrow polygonal walls, the surface, with which these walls stand on the body to be protected, is comparatively small. As a result, in the case of a force effect on the structure (e.g. impact of a body protected by a helmet on an obstacle), the specific pressure (N/cm²contact surface) is comparatively high. In order to reduce the specific pressure of a force effect on the top surface of the body to be protected in the case of equal absolute force application, a variant of the invention provides that at the lower edges of the polygonal walls contact surfaces are attached which increase the total area over which the forces are transferred to the body to be protected in order to thereby reduce the specific pressure and therefore increase in particular the wearing comfort and reduce the risk of injury due to the edges.
Advantageous configurations emerge from the following features:
In order to achieve an even distribution of the impact energy on the impact protection structure, it can be provided that the outer side and the inner side are each arranged in one surface. The surface can be flat or curved, in particular parabolic or hemispherical. The side wall is in this case aligned in the point, located on the surface, perpendicularly to the surface.
In order to further increase the wearing comfort or to prevent damage to an object to be protected, it can be provided that the impact protection structure has on the inner side an inner support surface formed by the cross-sectional surface of the side wall delimiting the side wall on the inner side. Padding can be arranged on the inner support surface in order to further increase the wearing comfort. The cross-section of a side wall is the surface between the edges of the side wall, with the edges each delimiting the interior of two cells adjoining one another, in particular on the outer and on the inner side of the impact protection structure.
In order to increase the stability of the structure and to improve the wearing comfort, it can be provided that the cross-section of the interior of the cells tapers from the outer side of the impact protection structure towards the inner side, with it in particular being provided that the side walls expand from the outer side towards the inner side, preferably at an angle of 0.5 to 5°, in particular 1°. The weight or possibly the impact energy can be better distributed by the expanded cross-section of the side walls on the inner side. The wearing comfort is improved due to the larger inner side or inner support surface without the weight being notably increased. In addition, the structure is particularly stable since a gradual stiffening occurs towards the inner side.
Particularly good damping properties are achieved when the side walls in the cross-section have a wall thickness of 0.5 mm to 50 mm.
A good protective effect with high flexibility can be achieved when the side walls have a height of 0.3 cm to 50 cm. For an impact protector, which is fastened to the body, the side walls preferably have a height of up to 6 cm. For impact mats, which are for example fastened to the border of a race track, the side walls can be up to 50 cm, in particular up to 20 cm.
Constructively, it is advantageous when, in the region of the recess, the surface of the side wall is reduced, with it in particular being provided that the recess is arranged on the outer side and/or on the inner side of the impact protection structure, with the height of the side wall being reduced in the region of the recess.
The recess is therefore arranged at an open end of a cell or at a closing end of a side wall. As a result, the stability of the structure can be very precisely controlled and the impact protection structure can be easily and cost-effectively produced. For example, it can be provided that, in side walls adjoining one another, a recess is alternately provided in the inner side and, in the next side wall, a recess is provided in the outer side. It is particularly advantageous when the recess is formed as an arc or polygon, in particular as a rectangle since a slight deformation of the impact protection structure is enabled during an impact which increases the brake path and improves the damping properties. At the same time, a particularly easy to control collapsing of the impact protection structure takes place when the impact takes place with high energy. The arc shape of the recesses also enables particularly good ventilation.
An improved protective effect through the selective deformation of the impact protection structure can be supported when the recess is arranged in a middle region of a side wall spaced apart from the adjoining side walls. As a result, the selective deformation is improved. Furthermore, the wearing comfort is increased since particularly effective ventilation is enabled and the impact protection structure also enables an improved fit through the easier deformability.
A particularly good protective effect through controlled deformation can be achieved when the recess has 0.01% to 70%, in particular 15% to 60%, preferably 30% to 50%, of the area of a side wall.
The protective effect can be further improved when 5% to 100%, in particular at least 20%, preferably at least 70% of the cells have at least one side wall with at least one recess. As a result, the impact energy is evenly distributed over the entire impact protection structure.
The transfer of the impact energy is improved when the surface of the side wall facing the interior is formed flat, or is composed of a plurality of in each case flat surface regions.
A particularly good protective effect can be achieved when the impact protection structure has a honeycomb structure or when the interior of at least one cell, in particular of a plurality of cells adjoining one another, has a polygonal, in particular hexagonal cross-section.
The weight of the structure or possibly the impact energy can be evenly distributed when the interior of a number of cells on the outer side and/or on the inner side of the impact protection structure has a polygonal, in particular hexagonal cross-section.
The impact protection structure is particularly stable when the cells have six side walls, with the edges of the side walls delimiting the cross-sectional surface of the interior and having an edge length, with opposing side walls each having the same edge length. In order to further improve the damping properties, it can be provided that four long side walls are provided with a longer edge length and two short side walls with a shorter edge length.
Damping properties and wearing comfort can be matched to one another particularly well by a recess being provided in at least two, in particular in all four long side walls of a cell opposing one another in relation to the interior and/or when a recess is not provided in two opposing, in particular short side walls of a cell. As a result, particularly good ventilation is achieved and a controlled deformation of the structure is supported.
The balancing of wearing comfort and damping properties can also be improved when the inner support surface of cells adjoining one another forms an arrow delimited by recesses, located in particular in the surface of the inner side and open on both sides. The inner side or the inner support surface therefore has substantially the shape of an I beam or a T beam. The loading transferred to the body to be protected can therefore be particularly effectively distributed. Furthermore, in order to increase the inner support surface and therefore the contact surface between impact protection structure and body to be protected, platelets protruding laterally from the in particular short side wall can be provided. The platelets can be arranged for example from the side wall laterally at an angle from the outer side towards the inner side, and the support surface formed by the platelets can in particular lie with the inner side in a common surface.
A particularly stable impact protection structure with a particularly good protective effect can be provided when the short side walls have 20% to 50% of the length of the long side walls. In particular, it can be provided that the short side walls have a length of 0.5 cm to 10 cm and the long side walls a length of 1 cm to 20 cm. As a result, good distribution of the weight or possibly of the impact energy is enabled.
In order to achieve a good protective effect through high stability and selective deformability with low weight and high weather resistance, it can be provided that the impact protection structure consists of a thermoplastic elastomer, in particular of polyurethane, copolyester, polyamide, polyolefin and/or styrene block copolymer. The thermoplastic polymer can be present in a foamed manner such that thicker side walls are enabled which allow a larger inner support surface with the same weight and thus improve both the wearing comfort and the fall damping.
A further aspect of the invention is to provide an impact protector which achieves optimal protection with low weight and high wearing comfort.
This object is achieved by the characterizing features of claim 15.
An impact protector, in particular a helmet, comprising an impact protection structure according to the invention is particularly effective, with fastening means being provided to fasten on a body to be protected, and the inner side can be arranged facing the body and with the recess being provided on the inner side.
Through the fastening means, the impact protection structure can be particularly effectively positioned such that the structure can be particularly well adapted to the requirements. As a result, a particularly good protective effect can be achieved. When the recess is provided on the inner side, particularly effective ventilation is achieved.
The object of the invention is also to provide an impact protector with a particularly good protective effect, with rotational movements, which may occur during an impact, having to be absorbed.
This object is achieved by the characterizing features of claim 16.
According to the invention, an impact protector is provided with an, in particular previously described impact protection structure according to the invention, and an outer shell is provided on an outer side of the impact protection structure, which can be arranged facing away from the body to be protected, said outer shell being connected in a punctiform manner to the impact protection structure such that the impact protection structure and the outer shell are displaceable with respect to one another.
The impact protector has a good protective effect. Through the punctiform connection, displacement in all directions along the outer side of the impact protection structure is possible such that a greater proportion of the energy transferred during an impact is transferred into the rotation between outer shell and impact protection structure. Rotations, which develop through the impact, are not transferred to the body to be protected, but rather displacement only takes place inside the impact protector, with a displacement into the x-y-z direction being possible. In the case of a helmet, an impact is therefore absorbed both in the direction of a nodding movement or yes movement, in the direction of a rotation of shoulder to shoulder or no movement, from ear to ear laterally over the head. In the case of an impact, the energy acting on the head can therefore be notably reduced. Since the energy is better absorbed, the height of the impact protection structure can be reduced such that a lighter and more compact impact protector with high wearing comfort can be provided.
The displaceability between outer shell and impact protection structure is improved when the impact protection structure is formed so as to be flexible. The protective effect is increased further as a result since individual adaptation of the impact protection structure is possible in the case of a rigid outer shell. In this case, it can be provided that the impact protection structure can be compressed transversely to the intended impact direction. This can for example be achieved by a previously described impact protection structure being provided.
Rotational movements can be particularly effectively absorbed when the outer side of the impact protection structure is arranged in a curved, in particular parabolic surface.
In order to achieve a particularly effective protective effect and to enable a rapid and simple use, fastening elements, in particular belts, for fastening the impact protector to a body can be provided at the connection points.
The protective effect is particularly good when the outer shell is formed from a polycarbonate or a carbon fiber material. These materials have particularly good damping properties.

A particularly advantageous embodiment of the invention is represented by way of example on the basis of the following drawings without the general inventive concept being limited.

FIG. 1 shows an exemplary impact protection structure for a helmet in a frontal view.

FIG. 2 shows the helmet from FIG. 1 in a top view.

FIG. 3 shows the helmet from FIG. 1 in a rear view.

FIG. 4 shows the helmet from FIG. 1 in a side view.

FIG. 5 shows the helmet from FIG. 1 in an oblique view.

FIG. 6 shows the helmet from FIG. 1 in a view from below.

FIG. 7 shows the helmet from FIG. 1 in an oblique view from laterally below.

FIG. 8 shows the helmet from FIG. 1 in an oblique view from the front, below.

FIG. 9 shows the helmet from FIG. 1 in a view from the rear, below.

FIGS. 10 to 10 h different possible designs of the individual cells according to the invention.

FIGS. 11a to 11f different designs of the side walls according to the invention.

FIGS. 12a to 12b embodiments of arrangements of cells with and without recesses.

FIGS. 13 to 13 c designs of cells with support surfaces or feet.

FIGS. 14a to 14d alternative designs of the side walls.

FIG. 1 shows an impact protection structure according to the invention for a helmet, in particular a bicycle helmet, in a frontal view to the front end of the helmet. The impact protection structure consists of a plurality of cells arranged next to one another. The cells have a hollow interior 1, which is delimited by side walls 2, with cells adjoining one another having a common side wall 2. The cells are open upwards and downwards.
The height of the side walls 2 determines the height of the impact protection structure or the distance between an outer side 3 of the impact protection structure and an inner side 4 of the impact protection structure. The height of the side walls can be 0.3 to 6 cm. A height of up to 50 cm is also possible for impact protection structures, which are not supported on the body.
The side walls 2 can have a wall thickness of 0.5 mm to 50 mm and have a wall thickness of 1 mm in the represented embodiment on the outer side 3. Furthermore, the side walls 2 can expand from the outer side 3 towards the inner side 4 at an angle of 0.5° to 5° and expand in the represented embodiment towards the inner side 4 by 1°. The interior 1 therefore tapers from the outer side 3 towards the inner side 4. The outer side 3 and the inner side 4 are each arranged in one surface. The surface can be flat or curved, in particular parabolic or hemispherical in each case. In the embodiment represented, this surface is in each case curved.
The outer side 3 is formed in a partial region from the front end to the neck end and in a further partial region above the ear recesses of a polygonal, in the present embodiment, hexagonal structure. The hexagons each have four long sides of equal length and two short sides opposing one another. The short sides are arranged in the represented embodiment parallel to the front and neck end. Through this design, compression is particularly easily possible in the impact protection structure from the front to neck region, i.e. in the direction of a ‘yes’ nodding movement.
Fastening points are provided on the border region to fasten the impact protection structure to a body. The fastening points form the corner points of a regular trapezoid. The fastening points can be used as connection points 6 to connect with an outer shell.
What is not represented is the possibility concerning an independent partial aspect of the invention of providing an outer shell on an impact protection structure to improve the protective effect, with the outer shell being connected to the impact protection structure at connection points 6. The outer shell can for example consist of polycarbonate with a thickness of 0.5 to 3.5, in particular 1.5 mm.
The represented embodiment of the impact protection structure according to the invention is manufactured from a thermoplastic elastomer in an injection-molding process. The thermoplastic elastomer can be a polyurethane, copolyester, polyamide, polyolefin or styrene block copolymer or a polyblend.
FIG. 2 and FIG. 3 show that the hexagonal structure of the outer side 3 is formed over the entire longitudinal side of the head, i.e. from the front end to the neck end. In this partial region, the side walls 2 in the represented embodiment have a height of 31 mm. The side walls 2 therefore have a wall thickness of 2.2 mm on the inner side 4.
FIG. 4 and FIG. 5 show that a partial region with the hexagonal structure is also formed laterally, above the ear recesses. In this partial region, the side walls 2 in the represented embodiment have a height of 22 mm. The side walls 2 therefore have a thickness of 1.1 mm on the inner side 4.
The height of the side walls 2 continually decreases between the middle and the lateral partial regions with hexagonal structure such that the outer side 3 and the inner side 4 are arranged on one surface.
FIG. 4 shows that in the represented embodiment cells, which are arranged on the border of the impact protection structure or between the regular partial regions, and also have a polygonal structure.
FIG. 6 shows the impact protection structure viewed from the inside of the helmet. In the middle region of the helmet, which is arranged on the crown, the inner side 4 also has a hexagonal structure. The cells in this region also have four long side walls 2 of equal length and two short side walls 2 opposing one another in relation to the interior 1. The long side walls 2 each have in the inner support surface 4 a recess 5. The height of the side wall 2 reduces in the region of the recess 5. The recess 5 is in each case arranged in the middle region of the side walls 2, spaced apart from the adjacent side walls 2. The recesses 5 are formed in an arc-shape in the partial regions with hexagonal structure. In the represented embodiment, the recesses 5 have a size of 10*12 mm or 8*12 mm in the partial region as a function of the height of the side wall 2. The inner support surface formed on the inner side 4 by the cross-section of the side walls 2 is formed in the partial region in the form of an arrow with two open ends or in the form of an I beam or T beam 7.
FIG. 7 shows that this design is also reflected in the side regions such that a majority of the inner side 4 has this I beam shape or T beam shape 7.
FIG. 8 shows that the design of the impact protection structure changes from the crown region to the neck region. In this region, the interior 1 of the cells tapers due to the curvature of the impact protection structure. The inner side 4 is in this region formed in a rhombus shape without a recess. Another design of the inner side 4 is also found in the border regions and between the partial regions with hexagonal structure.
FIG. 9 shows that on the inner side 4 is formed an inner support surface formed by the cross-sectional surface of the side walls 2 in the form of an arrow 7 with two open ends or in the form of an I beam or T beam. The inner support surfaces are spaced apart from one another by recesses 5. The recess in the partial region with hexagonal structure occupies approx. 45% of the area of the side wall 2. As a result, good ventilation, a notable weight reduction and selective deformation or possibly a selective collapsing of the impact protection structure can be achieved.
The represented embodiment of the impact protection structure therefore offers a good protective effect with high wearing comfort.
The invention provides in a preferred embodiment a polygonal and/or round and/or oval, prism-shaped thermoplastic structure of the cells or of the impact protection structure, hereinafter referred to only as “polygonal or cylindrical prism structure”. From substantially along a normal vector to the plane of the respective polygon or cylinder or extruded polygon (FIG. 10a ), whose walls or side walls 2 with deviations of up to +/−60° (angle α, FIG. 10b ) are oriented substantially perpendicular to the top surface of the body to be protected, i.e. perpendicular to the curved inner side 4. The wall thickness of the extruded polygonal structure is 0.1% to 40% of the average diameter of the respective polygon, the height of the wall or side wall 2 itself can be 10% to 1000% of its wall thickness. The profile of the side wall 2 or of the wall of the cells can in the side elevation correspond to a rectangle (FIG. 11a ), to a positive trapezoid (FIG. 11b ), to a negative trapezoid (FIG. 11c ), to a positive double trapezoid (FIG. 11d ), to a negative double trapezoid (FIG. 11e ), to an ellipsoid (FIG. 11f ) or to another geometric or irregular surface. The edges of the side wall 2 in the side elevation can be configured either straight or arced or partially straight and partially arced on the inner side 4 and/or the outer side 3. The walls of the respective polygons or cylinders or of the cells can in the top elevation be either straight or arced or partially straight and partially arced and have different geometric shapes (FIGS. 14a to 14d ). The walls or the side walls 2 of each extruded polygon or of the cell can optionally be parallel to one another such that each wall or side wall 2 can also follow a suitable extrusion vector (FIG. 10c ). An extrusion vector is in this case understood as the vector under which the polygon base surface, i.e. the polygon along the height or the cell or the side wall 2 extends to the cover surface of the cell. In this case, during extrusion, edges can also collapse such that the polygon or the cell has on one side, i.e. the inner side 4 or the outer side 3, more or fewer sides than the polygon or the cell on the inner side 4 or the outer side 3 or on the other side (FIG. 10d, 10e ). Similarly, the polygon of one side can be larger or smaller than the polygon of the other side (FIG. 100, which means that the polygon or cylinder or the cell undergoes a negative or positive tapering of the structure from outside inwards or from the outer side 3 towards the inner side 4 or vice versa. The polygon of one side can also have a different geometry to the polygon of the other side (FIG. 10g ). Extrusion curves can also be used instead of the extrusion vectors (FIG. 10h ). In particular, a plurality of extrusion vectors and/or extrusion curves can also be used for each side wall 2 in order to form the cells or the polygon structure.
The invention also provides selective weakening points of one or a plurality of walls of all or individual walls or side walls 2 of the polygonal or cylindrical prism structure (FIGS. 12a and 12b ). In this case,

- either recesses 5 or slots in the “lower region”, i.e. on the side of the polygonal or cylindrical prism structure which is arranged closer to the object to be protected or to the inner side 4;
- and/or recesses 5 or slots in the “upper region”, i.e. on the side of the polygonal or cylindrical prism structure which is arranged further from the object to be protected or from the outer side 3;
- and/or recesses 5 arranged at other points of the polygonal or cylindrical prism structure;
- and/or the wall thickness of the polygonal or cylindrical prism structure selectively thinned at one or a plurality of the mentioned points;
- and the recesses 5 and the thinned portions can be arranged either in the region of the surfaces of a wall or a plurality of walls of the polygonal or cylindrical side walls 2;
- and/or can be arranged in the region of the corner edges of two or a plurality of walls or side walls 2 of the polygonal or cylindrical walls;
- and the area of the recesses 5 and/or the thinned portions can be 0.1% to 70% of the sum of all wall surfaces of each individual polygonal and/or cylindrical wall connection and between 0.1% and 70% of all polygonal and/or cylindrical wall connections;
- and the layout of a recess 5 can take any desired shape, including in particular rectangles, trapezoids, triangles, other polyhedrons, round and/or oval, convex and/or concave shapes;
- and the recesses 5 can also serve to supply fresh cool air and/or to discharge already heated cool air;
- and for the loading limits, from which a folding-in of the structure is initiated through the recess 5 and/or thinned portion of the wall of the cell or the side wall 2 and/or the edge (target bend point), in addition to the climatic conditions and the material of the structure, in particular height, width, outline and area of the recess 5 or thinned portion of the wall, in this respect are relevant, as thicker walls, more rigid materials, lower temperatures and smaller or fewer sections or recesses 5 or thinned portions generally speaking have a stiffening effect on the structure and conversely, thinner walls, softer materials, higher temperatures and larger or more sections or thinned portions generally speaking have a softening effect on the structure such that with variations of these variables for the respective application, for the respective standards and for the respective other framework parameters (e.g. ski helmet, low temperatures, bicycle helmet, high temperature) the structures can each be optimized in regard to the desired target parameters, including in particular also the target parameters “low overall weight of the structure”;
- with all mentioned factors substantially contributing to keeping the flanks of the curve of the in particular negative acceleration during the conversion of kinetic energy into heat energy as rigid as possible and the plateau wide and low in order to thereby reduce the loading peaks and to avoid in this manner injuries and destruction of the respectively protected body.

The invention further comprises the possibility of attaching “feet” 9 to the (inner) side or inner side 4 of the impact protection structure or the cells facing the protected body, and these feet 9 can be any desired size and thickness and any desired layout. These feet 9 can in particular be oriented in the form of an inverted T beam, with the cross beam downwards, towards the body to be protected and the wall being attached as a longitudinal beam (FIG. 13a ) along the entire inner edge of the wall, along only one part of the walls or in particular only in a certain area in relation to the intersection points of the walls of the polygonal structure. In this case, the two transverse wings of the support surface can be oriented to one another not only at an angle of 180° (FIG. 13a ) but rather they also have a larger (FIG. 13b ) or smaller angle (FIG. 13c ). In particular in the case of a smaller angle (“inverted V position), there is a better adaptation to the different topographies of different head top surfaces. In this case, the cross-section resembles less an inverted T and more an inverted Y (FIG. 13c ).
The feet 9 or support surfaces, which are connected to the sides of the polygonal walls facing the body to be protected, are characterized in that

- the support surfaces or feet are oriented substantially parallel to the top surface of the body to be protected and in this manner enlarge the support surface or the feet of the structure on the body to be protected,
- and the support surfaces or feet 9 can have any desired thickness, contour and position;
- and in particular the two top surfaces of the support surfaces or feet 9 do not have to be parallel;
- and the support surfaces or feet 9 can be oriented in relation to the intersecting axis with the wall to one another either parallel (angle 180°) or in a positive or in a negative angle or can have a plurality of angle positions over the course along the edge;
- and the support surfaces or feet in this case in particular can be attached along the entire edges of the walls or side walls 2 or only one part of the walls or side walls 2 and/or can be attached only to the intersecting points of the polygonal walls.

An exemplary form of the invention provides a hexagonal structure to protect the head (=helmet), with the average diameter (distance opposing corners) of the hexagons being 35 mm, the wall thickness in the region close to the head, on the inner side 4 being 1.2 mm and in the region remote from the head, i.e. the outer side 4, being 1.0 mm, and the wall height being 32 mm.
Through the manner of construction of the impact protection structure according to the invention, the following positive effects of the invention result, with reference to the previous prior art:

- 1. Through the selective weakening of the structure by recesses/thinned portions, a “target fold point” develops at which the polygonal structure begins to fold in relatively early during the “brake process”. This folding-in process continues during the course of further impact into the adjoining wall structures.
- 2. Through the force-fitting connections of the walls with one another, there is a comparably resistant reaction of the structure, with the reaction taking place continuously at a comparatively flat level such that extremely high loading peaks are prevented.
- 3. Due to the folding in that has begun, the parts of the polygonal or cylindrical prism structure (walls, corners, bridges, edges, etc.), which have not even been weakened themselves, but which are connected in a force-fitting manner to a weakened or initially folded-in part, are gradually folded in. Due to the flexing work connected thereto, there is a conversion of the kinetic energy into heat energy. A permanent plastic deformation of the structure largely does not take place in the normal range.
- 4. In the case of the specific structure, the volume of the air space in the region between inner level (level of the “lower” end of the walls) and the outer level (level of the “upper” end of the walls) prevails such that there is enough space for the folding in of the components of the structure. The structure can therefore fold in comparatively easily to the extent of the air space. Furthermore, the polygonal network of walls transfers fold-in torques to adjoining walls, which are not directly affected by the impact, such that the region, in which the kinetic energy is converted by flexing work into heat energy, is enlarged. If the air space comprises e.g. 80% of the total space, then the structure can also fold in to around 20% of its starting height (and, depending on the elastic compressibility of the material used for the structure, even beyond this). The available “brake path” is therefore in this case around 80% (or more) of the original structural height of the protection structure. As a result, a comparatively long “brake path” can be implemented, whereby in turn the loading peaks are lower.
- 5. The structure begins to fold out again directly following the end of the force input (=end of the phase of the negative acceleration). The folding-out process is in this case, depending on the material used for the structure and climatic conditions, slower by the factor 2 to 50 than the folding-in process that took place under the force effect such that a “rebounce effect” cannot occur on the body to be protected (and therefore no double loading) in the case of the folding-out process. At the same time, the folding-out process is only very short such that the fully unfolded protection structure is available again in the case of a possible second impact following shortly after the first impact.
- 6. Through the selection of materials suitable for the respective climate window, a plastic deformation of the structure or even a breakage do not result in the case of falls according to EN 1078 because the structure can elastically adapt to the environment. As a result, the structure, unlike conventional structures, is also capable of multiple impacts.
- 7. The polygonal structure of the walls ensures that the structure does not simply “collapse in on itself” during normal force influences, but rather, especially in the event of an oblique force effect (much more frequent in practice), it folds towards the corresponding side. As a result, a further reduction of rotational accelerations is effected, with the result that consequences of injury in the case of an impact are excluded either entirely or are at least significantly lower.
- 8. Through materials, which can be applied only for the first place with the structure object of the invention (not conventional polystyrene), microcracks cannot occur as a result of (generally unrecognized) minimal prior damage. Therefore, the structure is also reliable in the cases where conventional protection structures made of polystyrene entail the high risk of a premature breakage as a result of (usually unrecognized) microcracks in the event of an impact.
- 9. The wearing comfort is increased by the contact surface, in particular in the case of the “inverted Y” variant the adaptation of the protection structure to different topographies of different head shapes is improved and the pressure of the support surfaces of the structure on the head top surface (N/cm²support surface) is significantly reduced by an enlargement of the support surface. This improves both the wearing comfort and reduces the risk of injury in the case of accidents.

Claims

1. An impact protection structure, in particular for a helmet, to absorb kinetic energy during an impact, in particular a fall, comprising a plurality of cells arranged next to one another, wherein each cell has a hollow interior (1), which is delimited by at least one side wall (2), wherein cells adjoining one another have at least one common side wall (2), wherein the interior (1) and the side walls (2) run from an outer side (3) of the impact protection structure to an inner side (4) of the impact protection structure opposing the outer side (3),

characterized in that at least one side wall (2) of a cell has at least one recess (5).

2. The impact protection structure according to claim 1, characterized in that the outer side (3) and/or the inner side (4) of the impact protection structure is arranged in a flat or curved, in particular parabolic or hemispherical surface.

3. The impact protection structure according to claim 1 or 2, characterized in that the impact protection structure on the inner side (4) has an inner contact surface (4) formed by the cross-sectional surface of the side wall (2) delimiting the side wall (2) on the inner side.

4. The impact protection structure according to any one of claims 1 to 3, characterized in that the cross-section of the interior (1) of the cells tapers from the outer side (4) of the impact protection structure towards the inner side (3), wherein in particular it is provided that the side walls (2) expand from the outer side (3) towards the inner side (4), preferably at an angle of between 0.5 to 5°.

5. The impact protection structure according to any one of claims 1 to 4, characterized in that the side walls (2) from the outer side (3) to the inner side (4) have a height of 0.3 cm to 50 cm, in particular of 0.5 cm to 20 cm and/or in that the side walls (2) in the cross-section have a wall thickness of 0.5 mm to 50 mm.

6. The impact protection structure according to any one of claims 1 to 5, characterized in that in the region of the recess (5) the surface of the side wall (2) is reduced, wherein it is in particular provided that the recess (5) is arranged adjoining the outer side (3) and/or the inner side (4) of the impact protection structure, wherein the height of the side wall (2) is reduced in the region of the recess (5).

7. The impact protection structure according to any one of claims 1 to 6, characterized in that the recess (5) is formed as an arc or polygon, in particular as a rectangle and/or

in that the recess (5) is arranged in a middle region of the side wall (2) spaced apart from the side walls (2) adjoining the respective side wall (2) and/or

in that the recess (5) is 0.01% to 70%, in particular 15% to 60%, preferably 30% to 50% of the area of the respective side wall (2).

8. The impact protection structure according to any one of claims 1 to 7, characterized in that 5% to 100%, in particular at least 20%, preferably at least 70% of the cells have a side wall (2) with a recess (5).

9. The impact protection structure according to any one of claims 1 to 8, characterized in that the surface of the side wall (2) facing the interior (1) is formed flat or is composed of a plurality of in each case flat surface regions.

10. The impact protection structure according to any one of claims 1 to 9, characterized in that the cells of the impact protection structure form a honeycomb structure and/or

in that the interior (1) has at least one cell, in particular a plurality of cells adjoining one another, a polygonal, in particular hexagonal, cross-section, wherein it is preferably provided that the interior (1) of a number of the cells on the outer side (3) and/or on the inner side (4) of the impact protection structure has a polygonal, in particular hexagonal, cross-section.

11. The impact protection structure according to any one of claims 1 to 10, characterized in that the cells each have six side walls (2), wherein the edges of the side walls (2) delimit the cross-sectional surface of the interior (1) and have an edge length, wherein side walls (2) opposing one another in relation to the interior (1) each have the same edge length and wherein it is in particular provided that four long side walls (2) are provided with a longer edge length and two short side walls (2) with a shorter edge length.

12. The impact protection structure according to any one of claims 1 to 11, characterized in that in each case one recess (5) is formed in at least two, in particular in all four long, side walls (2) of a cell opposing one another in relation to the interior (1) and/or

in that no recess (5) is formed in two, in particular short, side walls (2) of a cell opposing one another in relation to the interior (1).

13. The impact protection structure according to any one of claims 3 to 12, characterized in that the inner contact surface of cells adjoining one another forms an arrow delimited by recesses (5), located in particular in the surface of the inner side and open on both sides.

14. The impact protection structure according to any one of claims 1 to 13, characterized in that the impact protection structure consists of a, in particular foamed, thermoplastic elastomer, preferably of polyurethane, copolyester, polyamide, polyolefin and/or styrene block copolymer.

15. An impact protector, in particular helmet, comprising an impact protection structure according to any one of claims 1 to 14, characterized in that fastening means are provided for fastening to a body to be protected, wherein the inner side (4) of the impact protection structure can be arranged facing the body and wherein the recess (5) is provided on the inner side (4) of the impact protection structure.

16. The impact protector, in particular according to claim 15, comprising an impact protection structure, in particular according to any one of claims 1 to 14, characterized in that an outer shell is arranged on the impact protection structure at an outer side (3) of the impact protection structure which can be arranged facing away from the body to be protected.

17. The impact protector according to claim 16, characterized in that fastening elements, in particular belts, are provided at the connection points (6) for fastening the impact protector to a body.

18. The impact protector according to any one of claims 15 to 17, characterized in that the outer shell is formed of a thermoplastic material or polycarbonate or a carbon fiber material.