EP2987419A1 - Helmet - Google Patents

Abstract

The present invention relates to a helmet (1) comprising an outer shell (100) provided with openings (201-207; 201'-207 '; 202 ", 203", 205 ", 206") passing through the outer shell and having a front lower edge (300) and a top (310). The outer shell comprises a closed, centrally laterally located end zone (500) positioned so that the projected distance "H1" on a front vertical plane (XY) between a lower end (501) of the front area (500) and the edge lower frontal (300) is greater than one fifth of the distance "H" projected on the vertical frontal plane (XY) between the top (310) of the helmet (1) and the lower front edge (300). The outer shell comprises at least four beams each forming a continuous strip (101-106) delimited by apertures (201-207; 201'-207 '; 202 ", 203", 205 ", 206") and extending from the frontal zone (500) to a rear portion of the helmet (1) according to a meridian (101 'to 106'), one pole of which is positioned in the frontal zone (500).

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to the field of sports helmets. It finds for particularly advantageous application the cycling helmets for events where the aerodynamics of the cyclist is important.

STATE OF THE ART

In cycling, in test formats such as the time trial, the aerodynamics of the cyclist plays a decisive role in its performance.

To improve the aerodynamics, there are many helmets designed to protect the cyclist's head in case of shock while limiting the drag of the helmet. These helmets have a continuous outer shell and elongated shape towards the rear of the head. A helmet of this type is for example represented in figure 1 . This type of helmet has the disadvantage of preventing the evacuation of the heat generated by the skull of the cyclist. However, during intense efforts, the skull produces a large amount of heat that must be removed so as not to degrade the comfort and performance of the cyclist.

Furthermore, helmets having through openings distributed on the outer shell and allowing a heat exchange between the skull and the outside are known. A helmet of this type is represented in figure 2 . These helmets allow satisfactory ventilation of the skull but have a significant drag and therefore reduce the aerodynamic performance of the cyclist and therefore its speed. They are therefore not used in events such as the time trial.

Thus, there is a need to provide a helmet to cool satisfactorily the skull of the cyclist while maintaining good aerodynamic properties. This is the purpose of the present invention.

SUMMARY OF THE INVENTION

To achieve this object, an embodiment of the invention provides a helmet comprising an outer shell having through openings, a lower front edge and a top. The outer shell further comprises a closed end zone centered laterally and positioned so that the distance H1 projected on a frontal vertical plane between a lower end of the frontal zone and the front lower edge is greater than one fifth of the projected distance H on the vertical plane between the top of the helmet and the lower front edge.

The outer shell further comprises at least four beams each forming a continuous band delimited by openings and extending from the front zone to a rear portion of the helmet, according to a meridian, one pole of which is positioned in the frontal zone. .

The openings allow a heat exchange between the skull and the ambient air, thus allowing a good regulation of the temperature.

The particular arrangement of the frontal zone and the beams or bands allow the flow of air arriving on the helmet to flow aerodynamically on the outer shell. These beams or strips form guides for the flow of air to bring the latter from the frontal zone where the most important pressure is concentrated during the advance of the cyclist to the rear part of the helmet forming an edge of leak. They can significantly reduce the drag of the helmet. This is significantly lower than that of known helmets with conventional through openings and this even with a pitch angle of between 0 and 50 °.

• Les méridiennes des au moins quatre bandes se rejoignent en un point d'intersection située dans la zone frontale.
• Les ouvertures délimitant les bandes s'étendent le long d'une méridienne dont un pôle est positionné dans la zone frontale.
• Le casque comprend au moins une ouverture frontale, située dans une partie avant du casque et verticalement disposée entre le bord inférieur frontal du casque et la zone frontale.
• Selon un mode de réalisation, la zone frontale s'étend verticalement de sorte que : 1/5 H ≤ H1 ≤ 1/2 H, avec :
  • H1= la distance projetée sur un plan vertical frontal entre l'extrémité inférieure de la zone frontale et le bord inférieur frontal;
  • H= la distance projetée sur le plan vertical frontal entre le sommet du casque et le bord inférieur frontal.
• Selon un mode de réalisation, la zone frontale s'étend verticalement de sorte que : 1/5 H ≤ H2 ≤ 1/2 H, avec :
  • H2= la distance projetée sur un plan vertical frontal entre les extrémités inférieure et supérieure de la zone frontale;
  • H= la distance projetée sur le plan vertical frontal entre le sommet du casque et le bord inférieur frontal.
• La zone frontale s'étend latéralement de sorte que la largeur « W1 » de la zone frontale, correspondant à la distance projetée sur le plan vertical frontal entre les extrémités latérales de la zone frontale, est comprise entre le cinquième et les deux tiers de la largeur « W » du casque correspondant à la distance projetée sur le plan vertical frontal entre les extrémités latérales du casque.
• La projection de la zone frontale dans un plan vertical frontal s'inscrit dans un cercle dont le diamètre est compris entre 30 et 65 millimètres.
• La zone frontale est agencée de sorte qu'une perpendiculaire, de préférence toutes les perpendiculaires à la zone frontale, forme avec l'horizontal, un angle compris entre 0° et 50°.
• Une pluralité d'ouvertures parmi lesdites ouvertures est positionnée sur la partie antérieure du casque et s'étend sur une distance « L1 » inférieure à la moitié de la longueur « L » du casque.

Optionally, the invention may have any of the following optional features taken alone or in combination:

• The meridians of the at least four bands meet at a point of intersection in the frontal zone.
• The openings defining the strips extend along a meridian whose pole is positioned in the frontal zone.
• The helmet comprises at least one front opening, located in a front portion of the helmet and vertically disposed between the lower front edge of the helmet and the frontal area.
• According to one embodiment, the frontal zone extends vertically so that: 1/5 H ≤ H1 ≤ 1/2 H, with:
  • H1 = the distance projected on a frontal vertical plane between the lower end of the frontal zone and the lower frontal edge;
  • H = the distance projected on the frontal vertical plane between the top of the helmet and the lower front edge.
• According to one embodiment, the frontal zone extends vertically so that: 1/5 H ≤ H2 ≤ 1/2 H, with:
  • H2 = the distance projected on a vertical frontal plane between the lower and upper ends of the frontal zone;
  • H = the distance projected on the frontal vertical plane between the top of the helmet and the lower front edge.
• The frontal zone extends laterally so that the width "W1" of the frontal zone, corresponding to the distance projected on the frontal vertical plane between the lateral extremities of the frontal zone, is between one-fifth and two-thirds of the "W" width of the helmet corresponding to the distance projected on the vertical front plane between the lateral ends of the helmet.
• The projection of the frontal zone in a vertical vertical plane is in a circle whose diameter is between 30 and 65 millimeters.
• The frontal zone is arranged so that a perpendicular, preferably all perpendicular to the frontal zone, forms with the horizontal, an angle between 0 ° and 50 °.
• A plurality of openings among said openings is positioned on the front of the helmet and extends a distance "L1" less than half the length "L" of the helmet.

Other objects, features and advantages of the present invention will become apparent from the following description and accompanying drawings. It is understood that other benefits may be incorporated.

BRIEF DESCRIPTION OF THE FIGURES

• La figure 1 est une vue de côté d'un cycliste équipé d'un casque selon une première solution de l'art antérieur.
• La figure 2 est une vue de côté d'un cycliste équipé d'un casque selon une deuxième solution de l'art antérieur.
• La figure 3 est une vue de face d'un exemple de réalisation d'un casque selon l'invention.
• La figure 4 est une vue en perspective du casque illustré en figure 3, vue depuis l'avant et le dessus du casque.
• La figure 5 est une vue en perspective du casque illustré en figure 3, vue depuis l'arrière et le dessus du casque.
• La figure 6 est une vue de côté du casque illustré en figure 3.
• La figure 7 est une vue du dessous du casque illustré en figure 3.

The objects, objects, as well as the features and advantages of the invention will become more apparent from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

• The figure 1 is a side view of a cyclist equipped with a helmet according to a first solution of the prior art.
• The figure 2 is a side view of a cyclist equipped with a helmet according to a second solution of the prior art.
• The figure 3 is a front view of an embodiment of a helmet according to the invention.
• The figure 4 is a perspective view of the helmet shown in figure 3 , seen from the front and the top of the helmet.
• The figure 5 is a perspective view of the helmet shown in figure 3 , seen from the back and the top of the helmet.
• The figure 6 is a side view of the helmet shown in figure 3 .
• The figure 7 is a bottom view of the helmet shown in figure 3 .

The drawings are given by way of examples and are not limiting of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the rest of the description, the terms "vertical", "horizontal", "transverse", "longitudinal", "forward", "back", "lower", "upper", etc. will be used. These terms should be interpreted in a relative manner to the position of the helmet when it is positioned on the skull of a user wearing his head right. Note that in use, due to the position of the cyclist on the bike, his head is generally not straight but is inclined to the ground. In the context of the present invention, the directions are described with reference to a right head port as illustrated in FIG. figure 3 and not in reference to a position of use, which varies according to the bikes or cyclists.

An orthogonal reference is represented on the figures 3 , 6 and 7 . According to this reference, the plane XY corresponds to the plane containing the plate of the figure 3 . This plane is qualified in the following description of frontal vertical plane. The YZ plane corresponds to a horizontal plane.

The vertical direction is oriented along the X axis, the transverse direction along the Y axis and the longitudinal direction along the Z axis. In use, the cyclist advances substantially in the Z direction.

The helmet 1 according to the invention comprises an outer shell 100. The outer shell defines an outer envelope extending vertically from a top 310 to a lower edge 300 forming a periphery. The outer envelope has a substantially continuous curvature, that is to say that it has no salient angle.

The helmet 1 is formed at least in part of a shock absorbing structure 200. This structure 200 is typically made of EPP (expanded polypropylene) or EPS (expanded polystyrene). The outer shell may be formed by this shock absorbing structure or by an additional layer covering the absorption structure. In the latter case, the outer shell will be for example an ABS (acrylonitrile butadiene styrene copolymer). It may also provide a polycarbonate (PC), linen, carbon fibers or glass fibers to achieve this outer shell.

The helmet includes a plurality of through apertures 201-207, 201'-207 ', 202 ", 203", 205 ", 206". These through openings are at least practiced in the shock absorption structure 200 and in the outer shell 100. They extend substantially perpendicular to a plane tangential to the outer shell.

According to a non-illustrated embodiment, the through openings are covered with a mesh or other structure that can be traversed by a flow of air.

The outer shell 100 has a closed front area 500, that is to say without opening and located at a front portion of the helmet 1.

The outer shell extends longitudinally from the front zone 500 to a rear upper edge 303 located at the rear of the helmet 1. The outer envelope of this outer shell is configured so that the front zone 500 and the rear upper edge 303 respectively form a leading edge and a trailing edge for the flow of air flowing on the helmet 1.

This frontal zone 500 is centered laterally.

• des ouvertures 201-207, dont la direction principale d'élongation correspond à des méridiennes dont un pôle est la zone frontale 500.
• Des poutres ou bandes 101-106 formées entre deux ouvertures et qui s'étendent également selon des directions correspondant à des méridiennes dont un pôle est la zone frontale 500.

In this example, it is bounded by:

• openings 201-207, the main direction of elongation corresponds to meridians whose one pole is the front zone 500.
• Beams or strips 101-106 formed between two openings and which also extend in directions corresponding to meridians whose one pole is the front zone 500.

Each band 101-106 is thus centered on a median curve which forms a meridian 101 'to 106'.

The strips have a proximal end originating at the front zone 500 and a distal end formed by a trailing edge of the shell of the outer shell. This trailing edge forms an upper rear edge 303.

These strips 101-106 are continuous between these two ends. They do not show any interruption. Preferably, they have, according to a projection in an XY plane, a rectilinear section or curved towards the inside of the helmet. Preferably, they have a smooth surface state, that is to say, relatively rough to facilitate the flow flow, along their main direction of elongation.

Advantageously, the helmet 1 comprises at least three and preferably at least four continuous strips. In the example illustrated, the helmet comprises six continuous strips 101 to 106 from the front zone 500 to the upper rear edge 303.

The helmet also has two additional strips 107, 108, a proximal end of which originates at the front zone 500 and a distal end of which corresponds to the lateral lower edge 302 of the outer shell 100. This lateral lower edge 302 also forms an edge. leakage for the airflow.

The flow of air reaching the helmet during use exerts a maximum pressure on the frontal zone 500. This air flow reaching the front zone 500 then flows along the strips 101 to 108 to the edge. leakage formed by the upper rear edge 303 or the lower side edge 301. The drag of the helmet is thus limited.

The frontal zone 500 is flat or convex. In the latter case, this radius of curvature is between 50 and 200 mm and preferably between 90 and 160 mm. In the illustrated example, this radius of curvature is about 120 mm. Preferably, the surface state of the frontal zone 500 has a low roughness in order to facilitate the flow of the fluid on contact.

According to one embodiment, the frontal zone 500 is arranged so that any normal to the frontal zone 500 forms with the horizontal an angle between 0 and 50 °.

The frontal zone 500 may be flat or slightly curved.

The frontal zone 500 is in a circle or in a polygon, for example a rectangle. It is delimited by a lower end 501, an upper end 502 and lateral ends 503, these ends are defined by the separation between the front zone 500 and openings 201-209.

More precisely, the frontal zone 500 is delimited by the bands 101 to 108 and the openings 201 to 207.

According to one embodiment, it is also delimited by at least one and preferably two lower openings 208, 209 located between the frontal zone 500 and the lower edge 300 of the outer shell. In the case where the outer shell has two lower openings 208, 209, a junction 301 separates these two lower openings. These two lower openings allow to further lighten the helmet and aerate the forehead.

The distance projected on the vertical frontal plane XY between the top 310 of the helmet 1 and the lower frontal edge 300 is defined by "H".

• La distance H1 projetée sur un plan vertical frontal XY entre l'extrémité inférieure 501 de la zone frontale 500 et le bord inférieur frontal 300. Cette distance H1 est dimensionnée de sorte que 1/5 H ≤ H1 ≤ 1/2 H. Selon un mode de réalisation, 0.25 H ≤ H1 ≤ 0.4 H, et de préférence H1 = 0.3 H.
• La distance H3 projetée sur un plan vertical frontal XY entre une extrémité supérieure 502 de la zone frontale 500 et le sommet 310 du casque 1. Cette distance H3 est dimensionnée de sorte que 1/5 H ≤ H3 ≤ 1/2 H. Selon un mode de réalisation, 0.25 H ≤ H3 ≤ 0.4 H, et de préférence H3 = 0.3 H.
• La distance H2 projetée sur un plan vertical frontal XY entre les extrémités inférieure 501 et supérieure 502 de la zone frontale 500. Cette distance H2 est dimensionnée de sorte que 1/5 H ≤ H2 ≤ 1/2 H. Selon un mode de réalisation, 0.25 H ≤ H2 ≤ 0.4 H, et de préférence H2 = 0.3 H.

The frontal area can be positioned vertically by one or more of the following features:

• The distance H1 projected on a vertical frontal plane XY between the lower end 501 of the frontal zone 500 and the front lower edge 300. This distance H1 is dimensioned so that 1/5 H ≤ H1 ≤ 1/2 H. According to a embodiment, 0.25 H ≤ H1 ≤ 0.4 H, and preferably H1 = 0.3 H.
• The distance H3 projected on a vertical frontal plane XY between an upper end 502 of the frontal zone 500 and the top 310 of the helmet 1. This distance H3 is dimensioned so that 1/5 H ≤ H3 ≤ 1/2 H. According to a embodiment, 0.25 H ≤ H3 ≤ 0.4 H, and preferably H3 = 0.3 H.
• The distance H2 projected on a frontal vertical plane XY between the lower ends 501 and 502 of the frontal zone 500. This distance H2 is dimensioned so that 1/5 H ≤ H2 ≤ 1/2 H. According to one embodiment, 0.25 H ≤ H2 ≤ 0.4 H, and preferably H2 = 0.3 H.

The distances H1, H2, H3 and H are taken in a vertical direction X and are illustrated in FIG. figure 3 .

This vertical positioning of the frontal zone 500 makes it possible to locate the point of impact of the airflow defining the aerodynamic properties of the helmet when it is positioned in a normal configuration of use. Thus positioned, the frontal zone makes it possible to reduce the drag of the helmet 1.

According to this embodiment, the frontal zone 500 is positioned so that the projected distance on a vertical frontal plane XY between the center of the frontal zone 500 and the frontal lower edge 300 is greater than one quarter of the projected distance on the vertical plane. frontal XY between the top 310 of the helmet 1 and the lower front edge 300.

The distance projected on the vertical frontal plane XY between the lateral ends of the helmet 1 is defined by "W".

The frontal area is centered laterally to the helmet. It is characterized by a width W1, corresponding to the projected distance on the frontal vertical plane XY between the lateral ends 503 of the frontal zone 500, between the fifth and two thirds of the width "W" of the helmet. According to one embodiment, 0.15 W ≤ W1 ≤ 0.4 W, and preferably W1 = 0.2 W.

Distances W1 and W are taken in a horizontal direction Y and are illustrated in FIG. figure 3 .

According to one embodiment, the frontal zone 500 extends so that its surface S projected on the vertical frontal plane XY is between 15 and 30 cm ² and preferably between 20 and 24 cm ² and is preferably equal to 22 cm ^2. This further reduces the drag of the helmet 1.

The frontal zone may be dimensioned so that its surface S projected on the vertical frontal plane XY fits in a circle with a diameter ranging from 30 mm to 65 mm. In the embodiment described, the projected surface S is part of a circle 45 mm in diameter.

According to one embodiment, the median curves 101 'to 106', along which at least four strips 101-106 extend, intersect at an intersection portion included in the front zone 500. The portion intersection is located in a central surface of the frontal zone 500. According to the embodiment illustrated in FIG. figure 3 the intersection portion forms a point of intersection 505, the six median curves 101 'to 106' meeting at a common point. Advantageously, this improves the flow of air from the front zone 500 to the trailing edge via the strips 101-106.

According to one embodiment, the helmet comprises complementary openings 201'-207 ', 202 ", 203", 205 ", 206". These complementary openings are positioned in the rear part of the helmet with respect to the openings 201-207, so as to be respectively aligned with the corresponding openings 201-207 along a meridian, one pole of which is the frontal zone. Thus, the three openings 202, 202 'and 202 "extend along a meridian whose one pole is the frontal zone 500, separated by junctions, and the same is true of the aligned openings 201, 201', the openings aligned 203, 203 ', 203 ", aligned apertures 204, 204', aligned apertures 205, 205 ', 205", aligned apertures 206, 206', 206 "and aligned apertures 207, 207 '.

Thus, the helmet has, from one side edge to the other, alternating strips 101-106 and discontinuous cavities between the front area 500 and the trailing edge, consisting of the alignment of two or three aligned openings. Thus, each band is bordered by two discontinuous cavities. For example, the band 102 is formed by the aligned openings 202, 202 'and 202 "and the openings 203, 203' and 203".

The discontinuity of the cavities by junctions reinforces the structure of the helmet. Junctions enhance the helmet's strength and help protect the skull.

This construction provides the helmet with great strength while allowing good aeration of the skull and good aerodynamics.

The longitudinal openings that originate at the front zone 500 extend longitudinally, that is to say, in a projection in the XZ plane, at a distance L1 less than half the length L of the helmet. According to one embodiment, 0.2 L ≤ L1 ≤ 0.6 L, and preferably L1 = 0.4 L.

The distances L1, and L are taken in a vertical direction Z and are illustrated in FIG. figure 6 .

By bordering the front openings by junctions placed at the level of the first front half of the helmet, this makes it possible to obtain a good compromise between aeration and robustness of the helmet.

In addition, for the lower front anterior openings, the junction delimiting the posterior cut of these openings can be advanced to improve the helmet's performance.

The helmet also comprises rear openings formed between the upper rear edge 303 forming the trailing edge and a rear bottom edge 304 forming the rear end of the helmet 1. These rear openings 210 are delimited by a plurality of ribs 305 extending mainly vertically between the upper rear edge 303 and the lower rear edge 304.

According to one embodiment, the helmet also comprises a bridge 306 extending transversely to the ribs 305, mainly in the direction YZ to connect them and strengthen the strength of the rear part of the helmet.

According to the embodiment described, the helmet has a symmetry with respect to a vertical median longitudinal plane. In this example, the helmet comprises eight bands / beams. The invention also extends to helmets having more or fewer bands.

Wind tunnel tests have highlighted areas of helmets with low impact in the airflow. It is in these areas that openings can be made for ventilation without greatly affecting the aerodynamic properties of the helmet.

With respect to a point of impact of the airflow substantially corresponding to the point of intersection 505 of the medians defining the bands, it is possible to define the zones favorable to aerodynamics.

Thus, it is preferable to have strips 101-106 substantially centered respectively on the meridians passing through the point of intersection whose projection in an XY plane are oriented at 0 °, 30 °, 60 °, 120 °, 150 ° and 180 ° with respect to a horizontal plane. The strips can extend over a projected angular sector of plus or minus 7.5 °. In addition, the apertures 202-206 are preferably substantially centered respectively on the meridians passing through the point of intersection whose projections in an XY plane are respectively oriented at 15 °, 45 °, 90 °, 135 ° and 165 ° relative to each other. to a horizontal plane. The openings may extend over a projected angular sector of plus or minus 7.5 °.

In this example, the point of intersection is substantially located vertically half helmet height, in other words, this point is approximately equal distance from the top 310 of the helmet 1 and the lower front edge 300 (H / 2). This point of intersection can be shifted vertically according to the need in relation to the posture of the user in the practice of his sport. The point of intersection should correspond substantially to the point of contact of the airflow when the user is moving.

The previous zones organize ventilation in the projected part on an upper XY plane of the helmet. There are also ventilation openings in the projected part on a lower XY plane of the helmet.

In this example, two bands 107, 108 are provided. A first band 107 is substantially aligned with a direction projected in an XY plane passing through the point of intersection and oriented at 25 °, downward (clockwise), with respect to a horizontal plane. The second band 108 is symmetrical with respect to the vertical plane of symmetry of the helmet. Each of the two strips 107 and 108 is delimited respectively by two openings 207, 208 and 201, 209.

The location of the openings as defined above disturbs the aerodynamics of the helmet.

In view of the foregoing it is clear that the configuration of the frontal area of the helmet reduces the drag force while providing good aeration of the skull.

In particular, although particularly well suited to cycling helmets, the present invention also covers helmets intended for other sports where the aerodynamics and the ventilation of the skull are important such as helmets for the practice of roller skating.

It is possible to combine the embodiments described above.

The invention is not limited to the previously described embodiments and extends to all the embodiments covered by the claims.

REFERENCES

1.

Helmet

100.

Outer shell

101.

Bandaged

102.

Bandaged

103.

Bandaged

104.

Bandaged

105.

Bandaged

106.

Bandaged

107.

Bandaged

108.

Bandaged

101.

chaise longue

102 '.

chaise longue

103 '.

chaise longue

104 '.

chaise longue

105 '.

chaise longue

106 '.

chaise longue

107.

chaise longue

108.

chaise longue

200.

Shock absorption structure

201 to 207

Longitudinal openings

201 to 207 '

Longitudinal openings

202 ", 203", 205 ", 206"

Longitudinal openings

208

Front opening

209

Front opening

210

Rear openings

300.

Front lower edge

301.

Junction

302.

Lateral lower edge

303.

Rear top edge

304.

Bottom back edge

305.

Rib

306.

Bridge

310.

Mountain peak

500.

Frontal area

501.

Lower end of the frontal area

502.

Upper end of the frontal area

503.

Lateral extremities of the frontal area

504.

Circle

505.

Intersection portion

Claims (13)

Helmet (1) comprising an outer shell (100) provided with openings (201-207; 201'-207 '; 202 ", 203", 205 ", 206") passing through the outer shell and having a lower front edge (300 ) and a top (310), characterized in that : the outer shell comprises a closed, centrally laterally located end zone (500) positioned so that the distance "h1" projected on a vertical frontal plane (XY) between a lower end (501) of the front zone (500) and the edge front-end (300) is greater than one fifth of the distance "H" projected on the vertical frontal plane (XY) between the top (310) of the helmet (1) and the lower front edge (300), and in that the outer shell comprises at least four beams each forming a continuous strip (101-106), delimited by apertures (201-207; 201'-207 '; 202 ", 203", 205 ", 206") and extending from the frontal zone (500) to a rear portion of the helmet (1) along a meridian (101 'to 106'), one pole of which is positioned in the frontal zone (500). Helmet (1) according to claim 1, wherein the meridians (101 'to 106') of the at least four bands (101-106) meet at a point of intersection (505) in the frontal area (500). Helmet (1) according to any one of the preceding claims, wherein the openings (201-207; 201'-207 '; 202 ", 203", 205 ", 206") delimiting the strips (101-106) are extend along a meridian whose pole is positioned in the frontal zone (500). Helmet (1) according to the preceding claim, wherein the cavities (201-207; 201'-207 '; 202 ", 203", 205 ", 206") delimiting the strips (101-106) and extending along of a meridian whose pole is positioned in the frontal zone (500) are discontinuous and consist of the alignment of two or three openings (201-207; 201'-207 '; 202 ", 203", 205 ", 206 "). Helmet (1) according to any one of the preceding claims, comprising at least one front opening (208, 209) located in a front part of the helmet (1) and vertically disposed between the front lower edge (300) of the helmet (1). ) and the frontal area (500). Helmet (1) according to any one of the preceding claims, wherein the frontal zone (500) extends vertically so that: $$\mathrm{1}/\mathrm{5}\mathrm{H}\le \mathrm{h}\mathrm{1}\le \mathrm{1}/\mathrm{2}\mathrm{H},$$

with: H1 = the distance projected on a vertical frontal plane (XY) between the lower end (501) of the frontal zone (500) and the lower front edge (300); • H = the distance projected vertically (XY) between the top (310) of the helmet (1) and the lower front edge (300). Helmet (1) according to any one of the preceding claims, wherein the frontal zone (500) extends vertically so that: $$\mathrm{1}/\mathrm{5}\mathrm{H}\le \mathrm{h}2\le \mathrm{1}/\mathrm{2}\mathrm{H},$$

with: • h2 = the distance projected on a frontal vertical plane (XY) between the lower (501) and upper (502) ends of the frontal zone (500); • H = the distance projected vertically (XY) between the top (310) of the helmet (1) and the lower front edge (300). Helmet (1) according to any one of the preceding claims, wherein the frontal zone (500) extends vertically so that: $$\mathrm{1}/\mathrm{5}\mathrm{H}\le \mathrm{h}3\le \mathrm{1}/\mathrm{2}\mathrm{H},$$

with: • H3 = the distance projected on a frontal vertical plane (XY) between the upper end (502) of the frontal zone (500) and the vertex (310) of the helmet (1); • H = the distance projected vertically (XY) between the top (310) of the helmet (1) and the lower front edge (300). Helmet (1) according to any one of the preceding claims, wherein the frontal zone (500) extends laterally so that the width "w1" of the frontal zone, corresponding to the distance projected on the vertical frontal plane (XY ) between the lateral ends (503) of the frontal zone (500) is between one fifth and two thirds of the width "W" of the helmet corresponding to the distance projected on the vertical frontal plane (XY) between the lateral ends helmet. Helmet (1) according to any one of the preceding claims, wherein the projection of the frontal zone (500) in a frontal vertical plane (XY) is in a circle (504) whose diameter is between 30 and 65 millimeters. Helmet (1) according to any one of the preceding claims, wherein the front zone (500) extends so that its surface (S) projected on the vertical frontal plane (XY) is between 15 and 30 cm ² . Helmet (1) according to any one of the preceding claims, wherein the frontal zone (500) is arranged such that a perpendicular, preferably all perpendicular to the frontal zone (500), forms with the horizontal, a angle between 0 ° and 50 °. A helmet (1) according to any one of the preceding claims, wherein a plurality of apertures (201-207) among said apertures (201-207; 201'-207 '; 202 ", 203", 205 ", 206" ) is positioned on the front of the helmet and extends a distance "d1" less than half the length "D" of the helmet (1).

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