US20180153237A1

US20180153237A1 - Body Protection

Info

Publication number: US20180153237A1
Application number: US15/568,525
Authority: US
Inventors: Gerhard Karall
Original assignee: Hg3 SARL
Current assignee: Hg3 SARL
Priority date: 2015-04-24
Filing date: 2016-04-22
Publication date: 2018-06-07
Also published as: CN107529834A; ES2793328T3; CL2017002674A1; MX2017013600A; DE202016008835U1; AU2016251682A1; WO2016170167A1; EP3285606A1; FR3035300B1; FR3035300A1; BR112017022557A2; PL3285606T3; MX372581B; EP3285606B1; CA2983195A1

Abstract

This invention relates to a structure for absorption and/or dissipation of mechanical shocks comprising:

- connectors forming an aerated base with a base surface;
- protuberances, each of the protuberances comprising a central axis along which it extends from the aerated base, the central axis being normal to the base surface, two adjacent protuberances being connected to each other by a connector.

It also relates to a body protector at least partly made using the structure and protective clothing comprising at least one such protector.

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates to the technical field of body protection and more particularly the technical field of structures for the absorption and/or dissipation of mechanical shocks, body protectors and protective clothing.

BACKGROUND ART

The term “body protector” usually refers to an arrangement of materials that absorb and/or dissipate energy generated during an impact in order to give some protection to the part of the body facing the protection under normal conditions of use. This energy absorbing and/or dissipating material may or may not be structured.
Such body protectors are usually incorporated into protective clothes worn when engaging in a particular activity, and particularly for parts of the body to be protected against mechanical shocks. Examples of these zones include the shoulders, elbows, forearms, hips, knees, upper part of the tibia, middle part of the tibia, lower part of the tibia, the entire tibia, the back or the head.
Examples of such body protectors are presented in standards EN1621-1: 2013 and EN1621-2: 2014 relating to clothes for protection against mechanical shocks for motor cyclists.
These body protectors usually have to be made of a material capable of absorbing and/or dissipating forces generated during a mechanical shock. However, other criteria must also be considered to provide body protectors that are comfortable to wear. Thus, body protectors should be flexible to adapt to the shape of the part of the body to be protected, particularly the joints, enable the wearer to move freely, be light weight and breathable.
A more specific example is presented for example in document EP 2399470. The protection element described in this document comprises a base and protuberances, each of the protuberances extending from the base and normal to it. The protuberances also include a through orifice.
Each of the protuberances is either a solid of revolution around a central axis (in other words the external wall and the internal wall of the protuberances are right cylinders with a circular base), or a solid with rotational symmetry of order 6 with a regular hexagonal base. The base in this case is not aerated, in other words there are no other orifices in the material, apart from the orifices passing through the protuberances. Due to the presence of through orifices, the protection element and the body protector have some breathability, but it would be useful to make the material even more breathable while maintaining shock resistance properties.
Another solution would be to make elastomer nets like those described in WO99/56570, but according to current knowledge, such nets do not have sufficient resistance to shocks under conditions dictated by standards, particularly those mentioned above.
Thus, there is still a need for a protection element for absorption and/or dissipation of mechanical shocks. Such a protection element should preferably be made sufficiently absorbent and/or dissipating, sufficiently breatheable, sufficiently lightweight, sufficiently flexible, sufficiently resistant at high and low temperatures and sufficiently comfortable.

SUMMARY OF THE INVENTION

The authors have succeeded in obtaining a satisfactory protection element, but only after long and unsuccessful trial and error.
Thus, this invention relates to a protection element in the form of a structure for the absorption and/or dissipation of mechanical shocks, comprising:
connectors forming an aerated base with a base surface; and
protuberances, each of the protuberances comprising a central axis along which it extends from the aerated base, the central axis being normal to the base surface, two adjacent protuberances being connected to each other by a connector.
This structure is sufficiently aerated and at the same time confers satisfactory mechanical shock resistance properties.
In this description, the term “aerated base” means a base with orifices other than facing the orifices in the protuberances, if any. Thus, the base of the structure of the protection element in document EP 2399470 is not aerated according to the sense of this invention, while the base shown in the appended FIGS. 1 to 4 is aerated. In the examples illustrated on these figures, the aerated nature of the base is conferred particularly by the spaces between connectors. Furthermore, the fact that it is specified that the connectors form the aerated base makes it clear that the base is composed of connectors only.
The term “base surface” always refers to the surface of the aerated base from which the protuberances extend.
The term “normal” and its derivatives should be understood in the geometric sense. Thus, throughout this presentation, when a normal relationship is mentioned in relation to the base surface, it should be understood that this relationship is contemplated at the considered location and that the term “normal” means “perpendicular” to the tangent plane of the base surface at the considered location. For example, the central axis of a protuberance is said to be normal to the base surface when, at the location of the central axis of the protuberance, the axis is perpendicular to the tangent to the base surface at this location.
The base surface can be plane, and in this case the concepts of normality and perpendicularity are the same. The base surface can be curved so as match the contours of the part of the wearer's body against which the structure is placed, to protect this part of the body.
Preferably, the breathability of the structure is 10 to 70%, preferably 18.5 to 58.5%, preferably 20 to 52.5%, preferably 26.5 to 46.5%, and preferably about 35%. This ensures sufficient aeration of the structure, making it more comfortable to wear the body protector and to wear the protective clothing inside which the protector is provided, even during intense physical activity.
Breathability is defined at the base surface and corresponds to the area of the base surface corresponding to an empty space as a percentage of the total area of the base surface.
Furthermore or alternately, the Shore A hardness of the structure is 5 to 90, preferably 11.5 to 68.5, preferably 18.5 to 46.5, and preferably about 25. Thus, the structure particularly meets the necessary requirements to achieve performance level 2 in standard EN1621-1: 2013 and/or performance level 1 in standard EN1621-2: 2014.
The Shore A hardness is measured with a durometer in accordance with standard DIN 53505: 2009.
Furthermore or alternatively, the ratio between the height of the protuberances and the thickness of the aerated base is 6 to 17, preferably 6.5 to 8.5, preferably 6 to 8, and preferably about 7.5. This ratio ensures light weight, breathability and mechanical strength properties of the structure.
The height of protuberances is the height measured from the base surface of the aerated base from which the protuberances extends up to the free ends of the protuberances, parallel to the central axis of the protuberances. If the free end of the protuberances is not parallel to the base surface, the level at the longest distance will be considered.
The thickness of the aerated base is the thickness of the connectors (see below).
The connectors are preferably cylindrical in shape, the directrix of the cylinder being colinear with the base surface. Thus, they can be in the form of a strip with plane surfaces (cylindrical with rectangular base). Alternatively, the connectors have a non-cylindrical shape, such as a domed or scooped strip. Preferably, the surface of the strips has a plane central part and two external parts tilted relative to the central part such that the cross-section of the connector colinear with the directrix and perpendicular to the base surface decreases with increasing distance from the central part. The cylinder may also have a circular or polygonal base (preferably a regular polygon such as a square or hexagon).
The connectors advantageously form a mesh pattern in which at least some and possibly all of the nodes are occupied by a protuberance. Preferably, the mesh pattern is homogeneous, in other words it is a mesh formed from a repeating pattern. Still preferably, the mesh pattern may be regular, in other words the pattern unit is a regular polygon. The pattern unit may be composed of 2, 3, 4, 5, 6, 7 or 8 connectors.
Furthermore or alternatively, the length of the connectors is 0.01 to 25 mm, preferably 0.50 to 17.5 mm, preferably 1.0 mm to 9.5 mm, and preferably 1.7 mm. The length of a connector is measured parallel to the base surface and between the external walls of the protuberances that the connector connects directly and physically. The external wall of the protuberances may be curved, in this case the shortest length will be used.
Furthermore or alternately, the thickness of the connectors is 0.1 to 1.4 mm, preferably 0.35 to 1.2 mm, preferably 0.55 to 1 mm, and preferably about 0.80 mm.
The thickness of the connectors, that is also the thickness of the aerated base, is measured normal to the base surface. The thickness of the connectors is not necessarily constant over the entire surface of the connectors, and in this case “thickness” should be understood to mean the maximum thickness. Thus, if each connector is a strip domed at its centre, the thickness is taken at the centre; on the other hand, if each of the connectors is a scooped strip, the thickness is taken at its lateral edges.
Furthermore or alternatively, the width of the connectors is 0.3 to 25 mm, preferably 1.2 to 17.5 mm, preferably 2.0 to 10.5 mm, and preferably about 3.0 mm.
Furthermore or alternatively, the ratio between the equivalent outside diameter of the protuberances measured at the base surface and the distance between the central axes of two adjacent protuberances is 0.65 to 1.5, preferably 0.76 to 0.93, preferably 0.8 to 0.89, and preferably about 0.85. Such a ratio ensures an optimum flexibility of the structure without loss of mechanical properties providing protection.
The equivalent outside diameter is the diameter of a circle inside which the external wall of the protuberance, taken perpendicular to the central axis, is inscribed with a maximum of common points between the circle and the external wall of the protuberance.
Furthermore or alternatively, the distance between two adjacent protuberances is 6 to 60 mm, preferably 7.5 to 43.5 mm, preferably 9.5 to 27.5 mm, and preferably about 11 mm. The distance between two adjacent protuberances is taken between the central axes of these protuberances and parallel to the base surface.
In one particular embodiment, all the protuberances are on the same side of the aerated base. Alternatively, the protuberances are present on each side of the aerated base, preferably the central axes of the protuberances on one side of the aerated base are aligned with the centre axes of the protuberances on the other side of the aerated base. As a variant, the central axes of the protuberances on one side of the aerated base are in staggered rows with the central axes of the protuberances on the other side of the aerated base. In the case in which the protuberances are present on both sides of the aerated base, the aerated base will have two base surfaces. In the case in which the characteristics depend on a base surface, the base surface to be considered will be the base surface from which the considered protuberance extends.
In one embodiment, each protuberance has an external wall that has a circular symmetry about the central axis. As a variant, each protuberance has an external wall that can be superposed on its image obtained by a 360°/n rotation about the central axis, where n is greater than 1, preferably greater than 2, preferably 2 to 10, preferably 3 to 10, preferably 4 to 8, preferably 5 to 7, and preferably 6. For example, the transverse cross section of the external wall is a regular polygon with 3 to 10 vertices, preferably 4 to 8, preferably 5 to 7, and preferably 6.
In one embodiment, the equivalent outside diameter of the protuberances is constant from the aerated base. This means that the protuberances are right cylinders (in the mathematical sense). As a variant, the equivalent outside diameter of the protuberances decreases linearly from the aerated base with an angle of more than 0° and equal or less than 30°, preferably more than 2° and equal or less than 15°, preferably more than 4° and equal or less than 8°, and preferably equal to about 6°. The angle of 6° is particularly suitable for easy stripping of the structure from its mould.
Furthermore or alternatively, the equivalent outside diameter at the base surface is 3 to 25 mm, preferably 5 to 20 mm, preferably 7 to 14 mm, and preferably about 9.5 mm.
Furthermore or alternatively, each of the protuberances has a through orifice therein which extends along the central axis, and defines an internal wall of the protuberance. This makes it possible to increase breathability of the structure and reduce its weight at the same time. As a variant, the orifice is not a through orifice but a orifice which is blind on the side of the aerated base, which reduces the weight of the structure without modifying its breathability.
In one embodiment, the internal wall has a circular symmetry about the central axis. As a variant, the internal wall can be superposed on its image by 360°/n rotation about the central axis, where n is greater than 1, preferably greater than 2, preferably 2 to 10, preferably 3 to 10, preferably 4 to 8, preferably 5 to 7, and preferably 6. For example, the transverse cross section of the internal wall is a regular polygon with 3 to 10 vertices, preferably 4 to 8, preferably 5 to 7, and preferably 6. In the latter case, if the transverse cross section of the external wall is also a regular polygon, it preferably has the same shape as the transverse cross section of the internal wall and the vertices of these polygons are angularly aligned.
In one embodiment, the equivalent inside diameter of the protuberances is constant from the aerated base. The equivalent inside diameter is the diameter of a circle inside which the internal wall of the protuberance, taken perpendicular to the central axis, is inscribed with a maximum of common points between the circle and the internal wall of the protuberance. Alternatively, the equivalent inside diameter of the protuberances decreases linearly from the base surface with an angle of more than 0° and equal or less than 30°, preferably more than 2° and equal or less than 15°, preferably more than 4° and equal or less than 8°, and preferably equal to about 6°. Alternatively, the equivalent inside diameter of the protuberances increases linearly from the base surface with an angle of more than 0° and equal or less than 30°, preferably more than 2° and equal or less than 15°, preferably more than 4° and equal or less than 8°, and preferably equal to about 6°. An angle of 6° is particularly suitable for easy stripping of the structure from its mould.
Furthermore or alternatively, the thickness of the protuberance is defined by the difference between the equivalent inside diameter and the equivalent outside diameter of the protuberance at the base surface. The thickness of the protuberance is 0.5 to 10 mm, preferably 0.65 to 7 mm, preferably 0.85 to 4 mm, and preferably about 1 mm.
Furthermore or alternatively, the height of the protuberances is 2 to 8.5 mm, preferably 3.5 to 7.5 mm, preferably 4.5 to 6.5 mm, and preferably about 6 mm.
The protuberances are preferably distributed in a regular mesh pattern, for example with a square mesh pattern (each protuberance having four neighbours) or a regular triangular mesh pattern (each protuberance having six neighbours). Consequently, all the connectors have the same length.
The structure is preferably made of a flexible material. Flexible means a material for which the global shape can be modified to make it better fit the shape of the body against which it is placed.
The flexible material is preferably a viscoelastic material, preferably with a vitreous transition temperature Tg between −20 and 50° C., preferably between 0 and 40° C., and preferably between 15 and 25° C. The vitreous transition temperature Tg can be obtained by a dynamic mechanical analysis using the ACOEM METRAVIB DMA+450 instrument. Although for manufacturing reasons it is easier to make the aerated base and the protuberances of the same viscoelastic material, it is also possible that the aerated base and the protuberances are made of different viscoelastic materials. It is also possible in both cases to provide two or more populations of different protuberances, each being made of a different viscoelastic material than the others.
In the remainder of this presentation, the quantities of compounds used in the composition of the viscoelastic material are expressed by weight relative to the total weight of the viscoelastic material.
The majority constituent of the viscoelastic material is a polymer such as polynorbornene, polyacrylonitrile, polyvinyl chloride (PVC), ethylene vinyl acetate (EVA) copolymer, chlorobutyl rubber and mixtures thereof, preferably polynorbornene alone or a mixture of polynorbornene with at least one of the other polymers mentioned above. By majority constituent is the constituent present in the largest quantity in the viscoelastic material should be understood.
The viscoelastic material can advantageously include 27 to 55% of polynorbornene, preferably 40 to 50%, preferably 42 to 48%, and preferably about 45%.
The viscoelastic material can also include a plasticiser such as an oil. Aromatic oils are preferred but a paraffin oil (PA), a naphthene oil (HNA), a silicone oil or C9 resins (particularly those supplied by Konimpex under the name “Hydrocarbon C9”) can also be used. The viscoelastic material advantageously includes 33 to 50% of plasticiser, preferably 37 to 45%, preferably 39 to 43% by weight, and preferably about 40%.
The viscoelastic material can also include a filler such as silica powder, kaolin powder, aluminium oxide (Al(OH)₃) powder, stearic acid powder or a mixture thereof. The viscoelastic material advantageously includes 4 to 8% of filler, preferably 5 to 7%, preferably 5.5 to 6.5%, and preferably about 6%.
The viscoelastic material can also include other compounds such as a preservative, an anti-oxidant, a UV stabiliser, an anti-scratch agent, a vulcanising agent, a vulcanisation accelerator and a colouring agent.
Examples of preservatives are aluminium hydroxide (Al(OH)₃), metal oxides such as zinc oxide (ZnO) or titanium dioxide (TiO₂), ethylene vinyl acetate (EVA), and an ethylene propylene diene monomer (EPDM). The viscoelastic material may also not contain any preservatives.
Examples of anti-oxidants are phenolic anti-oxidants (for example 2,6 di-ter-butyl-4-methyl phenol), phenyl-p-phenylenediamine and derivatives thereof such as N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD); the preferred antioxidants being phenyl-p-phenylenediamine and 6PPD.
Examples of UV stabilisers are paraffin waxes and metal oxides such as zinc oxide (ZnO) or titanium dioxide (TiO₂).
One example of an anti-scratch agent is N-(cyclohexylthio)-phthalmide.
Examples of vulcanising agents include sulphur and di(benzothiazol-2-yl) disulphide (MBTS).
Examples of vulcanisation accelerators include titanium dioxide (TiO₂), N-cyclohexyl-2-benzothiazole sulphenamide (CBS), bis(N,N-dimethylthiocarbamyl) disulphide, stearic acid, mixtures of accelerators such as Deovulc EG 3 which is a synergistic combination of highly active accelerators containing ethylenethiourea, available from DOG Deutsche Oelfabrik and King Industries, Inc., and metal oxides such as zinc oxide (ZnO) or titanium oxide (TiO₂), preferably stearic acid or mixtures of accelerators such as Deovulc EG 3.
Examples of colouring agents are preferably organic and inorganic pigments such as iron oxides (such as yellow or red oxides), titanium dioxide (TiO₂), zinc oxide (ZnO) or carbon black.
The structure for absorption and/or dissipation of mechanical shocks can be completely homogeneous, in other words its connectors and protuberances are arranged at regular intervals over the entire structure forming a single pattern and the structure for absorption and/or dissipation of mechanical shocks is made of a single material. Alternatively, the absorption and/or dissipation structure can comprise several different zones. These zones can be different from each other either by at least one dimension of one of its elements (connectors, protuberances), or by the material used to form the zones, or by at least one dimension of one of its elements and also by the material used to form the zones.
The invention also relates to a body protector made at least partially using the structure for absorption and/or dissipation of mechanical shocks described above.
For the purposes of this presentation, the term “body protector” means a structure for absorption and/or dissipation of mechanical shocks with appropriate dimensions or an arrangement of such structures with appropriate dimensions to provide a certain degree of protection to the part of the body facing the protection under normal conditions of use.
In its simplest embodiment, the body protector is made entirely from the structure for absorption and/or dissipation of mechanical shocks as described above.
Examples of body protector shapes are as given in standards EN1621-1: 2013 and EN1621-2: 2014 relating to clothes for protection against mechanical shocks for motor cyclists.
The body protector can be generally plane, in other words the aerated base of the structure for absorption and/or dissipation of thermal shocks of which it is made is itself plane. Thus, when it is integrated into protective clothing, the body protector is folded, the free ends of the protuberances moving towards or away from each other. The flexibility of the body protector can be increased by making generally V-shaped cuts in it, the tip of the V facing the inside of the protector and the diagonals extending to the edge of the protector. The diagonals of the V may be straight or curved. If the diagonals of the V are curved, they are curved on the same side. When folding, the diagonals of the V move towards each other and are then generally sealed to each other, for example by gluing or welding, the protector then forming a dish usually to contain the head or a joint such as the shoulder, elbow or knee. A small circular cutout can be provided at the tip of the V to make it easier to fold the body protector at this location. Small in this case means a circular cutout with a diameter of less than 5 mm.
The body protector can also be curved, in other words it does not need to be folded before it is incorporated into protective clothing: it already has the right curvature adapted to the part of the body to be protected. Thus, the structure for absorption and/or dissipation of mechanical shocks is directly shaped in the final use shape of the body protector.
In particular, the body protector at least satisfies performance level 1 given in standard EN1621-1: 2013 or in standard EN1621-2: 2014, preferably performance level 2. In particular, the body protector at least satisfies performance level 2 given in standard EN1621-1: 2013 and performance level 1 in standard EN1621-2: 2014.
The invention relates particularly to protective clothing comprising a body protector as described above.

DESCRIPTION OF THE DRAWINGS

The appended drawings are given for illustrative and non-limitative purposes to help the reader better understand this invention. These drawings include the following figures:

FIG. 1 is an oblique projection view of a particular embodiment of the structure for absorption and/or dissipation of mechanical shocks according to the invention with cylindrical protuberances with a circular base;

FIG. 2 is an oblique projection view of a particular embodiment of the structure for absorption and/or dissipation of mechanical shocks according to the invention with cylindrical protuberances with a regular hexagon shaped base;

FIG. 3 is a cross section perpendicular to the aerated base passing through the central axis of the protuberances; and

FIG. 4 is a top view of a protector according to the invention made entirely using the structure for absorption and/or dissipation of mechanical shocks according to the invention.

DESCRIPTION OF THE INVENTION

The same numeric references are used to designate equivalent elements in all the figures.
One particular example of the absorption and/or dissipation structure according to the invention is described below with reference to FIG. 1. The structure 1 is homogeneous.
This structure 1 for absorption and/or dissipation of mechanical shocks comprises connectors 2 forming a plane aerated base B with a base surface. The connectors are in the form of a strip with plane surfaces with the same length.
The structure 1 for absorption and/or dissipation of mechanical shocks also includes protuberances 3, each of the protuberances comprising a central axis AA along which it extends from the aerated base B, the central axis AA being normal to the base surface.
The protuberances 3 are present on only one side of the aerated base B. Each protuberance 3 has an external wall 31, the external wall 31 having a circular symmetry about the central axis. Each of the protuberances 3 has a through orifice which extends along the central axis AA and defining an internal wall 33 of the protuberance 3. The internal wall 33 has a circular symmetry about the central axis AA. The protuberances 3 are distributed in a regular triangular mesh pattern, in other words each of the protuberances has six neighbours and the central axes of the neighbours form a regular hexagon.
Another particular example of the absorption and/or dissipation structure according to the invention is described below with reference to FIG. 2. The structure 1 is homogeneous.
This structure 1 for absorption and/or dissipation of mechanical shocks comprises connectors 2 forming a plane aerated base B with a base surface. The connectors are in the form of a strip with plane surfaces with the same length.
The structure 1 for absorption and/or dissipation of mechanical shocks also includes protuberances 3, each of the protuberances comprising a central axis AA along which it extends from the aerated base B, the central axis AA being normal to the base surface.
The protuberances 3 are present on only one side of the aerated base B. Each protuberance 3 has an external wall 31, the transverse cross section of the external wall 31 being a regular polygon with 6 vertices (regular hexagonal polygon). Each of the protuberances 3 has a through orifice which extends along the central axis AA and defines an internal wall 33 of the protuberance 3. The transverse cross section of the internal wall 33 is a regular polygon with 6 vertices. The vertices of the regular polygons forming the transverse cross section of the external and internal walls are angularly aligned. The protuberances 3 are distributed in a regular triangular mesh pattern, in other words each of the protuberances has six neighbours and the central axes of the neighbours form a regular hexagon.
FIG. 3 shows an exemplary cross section perpendicular to the aerated base for the exemplary structures for absorption and/or dissipation of mechanical shocks of FIGS. 1 and 2.
On FIG. 3, the equivalent outside diameter D_eof the protuberances 3 decreases linearly from the aerated base B with an angle of 6° while the equivalent inside diameter D_iof the protuberances 3 increases linearly from the aerated base B at an angle of 6°.
An example of the dimensions of the different elements of the structure for absorption and/or dissipation of mechanical shocks is given in table 1 below.

TABLE 1

Structure for absorption and/or dissipation of mechanical shocks

thickness

6.8 mm

Protuberances

	height	6 mm
	equivalent outside diameter at the	9.5 mm
	aerated base
	protuberance thickness
	1 mm

Connectors

	length	1.7 mm
	width
	3 mm
	thickness	0.8 mm

Table 2 below gives an exemplary composition for the material used for the structure for absorption and/or dissipation of mechanical shocks. Quantities are expressed as a percentage by weight of the total composition.

	TABLE 2

	Polynorbornene	45%
	Oils	40%
	Silica	6%
	Anti-scratch agent	1%
	Vulcanising agent (sulphur)	1%
	Vulcanisation accelerator
	1%
	Colouring agent
	1%
	Stearic acid	<1%
	Antioxidant	<1%
	UV stabiliser (wax)	<1%

	The total does not add up to 100%, due to approximations.

The structure for absorption and/or dissipation of mechanical shocks with one of the configurations of FIGS. 1 to 5 and with the composition given in table 2 has a breathability of about 35% and a Shore A hardness of about 25. This structure make it possible to reach performance level 2 for standard EN1621-1 and level 1 for standard EN1621-2.
An exemplary body protector is described below with reference to FIG. 4. This exemplary body protector corresponds to the examples given in standard EN1621-1: 2013 (see FIG. 1 and table 1 in this standard). The body protector 10 can easily be defined using three parameters: two radii r₁, r₂and a length l. It comprises three parts centred on a longitudinal axis BB which is also an axis of symmetry of the body protector 10. A first end part 11 has the shape of a half-circle with radius r₁and a second end part 12 has the shape of a half-circle with radius r₂. The two end parts 11, 12 are connected to each other by a trapezoidal shaped central part 13 with the longitudinal axis BB as the axis of symmetry and height l.
Such a shape can be used to protect the following parts of the body: shoulder (S); elbow and forearm (E); hip (H); knee and upper part of the tibia (K); knee, upper and middle parts of the tibia (K+L); lower part of the tibia (L).
Table 3 below gives the minimum dimensions of the three parameters according to standard EN1621-1: 2013.

	TABLE 3

	Small model	Large model

	Type	r₁	r₂	l	r₁	r₂	l

S	55	32	64	70	40	80
E	45	24	118	50	30	150
K	55	24	100	70	30	130
H	35	26	70	44	33	88
L	32	24	64	40	30	80
K + L	55	24	185	70	30	240

Claims

1. Structure for absorption and/or dissipation of mechanical shocks comprising:

connectors forming an aerated base with a base surface;

protuberances, each of the protuberances comprising a central axis along which it extends from the aerated base, the central axis being normal to the base surface, two adjacent protuberances being connected to each other by a connector.

2. Structure according to claim 1, wherein the ratio between the height of the protuberances and the thickness of the aerated base is 6 to 17.

3. Structure according to claim 1, wherein breathability of the structure is 10 to 70%.

4. Structure according to claim 1, wherein the Shore A hardness of the structure is 5 to 90.

5. Structure according to claim 1, wherein the ratio between the equivalent outside diameter of the protuberances measured at the base surface and the distance between the central axes of two adjacent protuberances is 0.65 to 1.5.

6. Structure according to claim 1, wherein the protuberances are all on the same side of the aerated base.

7. Structure according to claim 1, wherein each protuberance has an external wall which has a circular symmetry about the central axis or can be superposed on its image by a 360°/n rotation about the central axis, where n is an integer greater than 1.

8. Structure according to claim 1, wherein the equivalent outside diameter of the protuberances is constant from the aerated base or decreases linearly from the aerated base with an angle of more than 0° and equal or less than 30°.

9. Structure according to claim 1, wherein each of the protuberances has a through or blind orifice therein, and which extends along the central axis and defines an internal wall of the protuberance.

10. Structure according to claim 1, wherein the internal wall has a circular symmetry about the central axis or can be superposed on its image by a 360°/n rotation about the central axis, where n is an integer greater than 1.

11. Structure according to claim 1, wherein the equivalent inside diameter of the protuberances:

is constant from the aerated base or

decreases linearly from the aerated base with an angle of more than 0° and equal or less than 30°, or

increases linearly from the aerated base with an angle of more than 0° and equal or less than 30°.

12. Structure according to claim 1, wherein the structure is made of a viscoelastic material.

13. Structure according to claim 12, wherein the majority constituent of the viscoelastic material is a polymer.

14. Body protector made at least partially from the structure according to claim 1.

15. Body protector according to claim 14 achieving at least performance level 1 in standard EN1621-1: 2013 or in standard EN1621-2: 2014.

16. Protective clothing comprising at least one protector according to claim 14.

17. Structure according to claim 1, wherein the protuberances are on each side of the aerated base.

18. Structure according to claim 1, wherein each protuberance has an external wall which can be superposed on its image by a 60°/n rotation about the central axis.

19. Structure according to claim 1, wherein each protuberance has an internal wall which can be superposed on its image by a 60°/n rotation about the central axis.

20. Structure according to claim 12 wherein the majority constituent of the viscoelastic material is chosen from the group consisting of: polynorbornene, polyacrylonitrile, polyvinyl chloride (PVC), the ethylene vinyl acetate (EVA) copolymer, chlorobutyl rubber and mixtures thereof.