EP3100625A1 - Sports helmet - Google Patents

Abstract

Helmet for sporting practice (1) comprising an injected outer shell (2) forming an envelope surface (S2) intended to be positioned on a skull, characterized in that the outer shell comprises at least one thin portion (21) whose thickness (e21) is less than or equal to 1.3 mm, the thin portion (21) representing at least 25% of the envelope surface (S2).

Description

The invention relates to a protective helmet for sports activity. Such activities may include downhill skiing, ski touring or snowboarding. The invention also extends to the practice of climbing, mountaineering, cycling or the practice of snowmobiling. Generally, a helmet forms a protection of the head, to protect the skull of the shocks that it could undergo when the user makes a fall or when an object is projected in its direction.

A classic helmet construction includes an outer shell and an inner cap. The outer shell is generally rigid, and is made of a thermoplastic material such as ABS (Acrylonitrile Butadiene Styrene) or PC (PolyCarbonate). Commonly, the inner cap is made of an expanded material such as EPS (Expandable PolyStyrene) or EPP (Expandable PolyPropylene). In order to guarantee good comfort for the user, the helmet is generally equipped with an internal cap which may, for example, be made of foam covered with fabric. The inner cap is attached to the inside of the inner cap.

To make a protective helmet for sporting activity, two technologies are generally used.

A first technology, called injection, consists of producing the outer shell and the inner cap separately. In a second step, the inner cap is assembled in the outer shell by appropriate connecting means such as clips, fasteners, rivets, glue, type VELCRO hooks ... This technology offers the possibility to separate the inner cap of the outer shell if necessary. This may be useful, for example, to replace a deteriorated part. By being made by molding, one can obtain a very good finish, different surface conditions and easily make openings through the shell. This allows you to use the shell directly without having to perform a recovery to get the desired rendering. However, the standard injection method only makes it possible to have external shells having a thickness greater than 2 mm. This has the consequence of weighing down the helmet and stiffening it. The relative rigidity of the outer shell does not allow it or little to deform. The outer shell thus contributes little to depreciation.

A second technology, called thermoforming or "in-mold", consists of producing the outer shell at first. In a second step, the outer shell is placed inside a mold in which a material is injected to produce the inner cap. Thus, the inner cap is directly connected to the outer shell to form a one-piece piece having an average thickness greater than five millimeters. Generally, the total thickness of the helmet is even greater than fifteen millimeters. This chemical grip is indémontable. It allows an excellent connection between the two parts. To achieve the outer shell, it is usually obtained by thermoforming. The shaping of the outer shell is obtained by hot deformation of a thin plate whose thickness may be less than 2 mm. The outer shell can be lightened which reduces the weight of the helmet. However, this thermoforming process produces parts having a poor quality finish. This implies subsequent recovery operations.

The invention aims to solve one or more of these disadvantages.

An object of the invention is in particular to provide an improved helmet.

One goal is to provide a lightweight helmet structure.

Another goal is to provide a helmet with good damping property.

Another goal is to provide a helmet whose outer shell has a good finish, without recovery operation.

The invention thus relates to a helmet for sporting practice comprising an injected outer shell forming an envelope surface intended to be positioned on a skull. The outer shell comprises at least one thin portion whose thickness is less than or equal to 1.3 mm, the thin portion representing at least 25% of the envelope surface.

Due to the small thickness of a portion of the outer shell injected, it is composed of less material, which allows to lighten the helmet. In addition, the small thickness of certain areas increases the deformability of the outer shell. Thus, being less rigid in places, the outer shell can further deform and absorb some of the shocks. The outer shell then contributes to the damping. On the other hand, the injection makes it possible to obtain a very good finish at the mold outlet, this makes it possible to avoid costly rework operation to achieve the desired appearance.

• la partie fine couvre une partie sommitale s'étendant du sommet du crâne jusqu'à un pourtour périphérique du crâne passant par les tempes du crâne,
• au moins 90% de la surface enveloppe présente une épaisseur inférieure ou égale à 1,3 mm,
• la calotte interne, distincte de la coque externe, est fixée à l'intérieur de la coque externe,
• la coque externe est constituée d'un matériau dont l'indice de fluidité à chaud en volume (MVR) est supérieur à 8 cm³/10min (selon ISO 1133),
• la coque externe est constituée d'un matériau parmi les matériaux suivants : PU, ABS, PP ou PC.

L'invention concerne également :

• un procédé de fabrication d'un casque pour la pratique sportive, incluant une étape d'injection de la coque externe par au moins un point d'injection situé sur un bord inférieur de la coque externe,
• le canal d'alimentation du au moins un point d'injection est orienté sensiblement tangentiellement à la surface enveloppe au niveau du bord inférieur.

According to advantageous but non-mandatory aspects of the invention, such a front stop may incorporate one or more of the following features, taken in any technically permissible combination:

• the thin portion covers a summit portion extending from the top of the skull to a peripheral periphery of the skull passing through the temples of the skull,
• at least 90% of the envelope surface has a thickness less than or equal to 1.3 mm,
• the inner cap, distinct from the outer shell, is fixed inside the outer shell,
• the outer shell is made of a material whose volume melt index (MVR) is greater than 8 cm ³ / 10min (according to ISO 1133),
• the outer shell is made of one of the following materials: PU, ABS, PP or PC.

The invention also relates to:

• a method of manufacturing a helmet for sporting practice, including a step of injecting the outer shell by at least one injection point located on a lower edge of the outer shell,
• the supply channel of the at least one injection point is oriented substantially tangentially to the envelope surface at the lower edge.

• la figure 1 est une vue en perspective avant d'un casque selon l'invention ;
• la figure 2 est une vue en coupe sagittale éclatée de la coque externe et de la calotte interne ;
• la figure 3 est une vue en perspective de dessous de la coque externe seule.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

• the figure 1 is a front perspective view of a helmet according to the invention;
• the figure 2 is an exploded sagittal sectional view of the outer shell and the inner cap;
• the figure 3 is a perspective view from below of the outer shell alone.

In the rest of the description, terms such as "horizontal", "vertical", "longitudinal", "transversal", "superior", "lower", "up", "down", "before" will be used. , " back ". These terms should be interpreted in a relative sense in relation to a helmet worn normally, head straight.

The figure 1 is a perspective view illustrating a helmet 1 for sports practice according to one embodiment of the invention.

The helmet 1 comprises an outer shell 2 and an inner cap 3. The inner cap 3 is housed in the internal volume of the rigid shell 2. It is fixed or injected on the inner face of the rigid shell 2. An inner cap, no shown, can be assembled inside the inner cap 3. The inner cap is for example made of foams surrounded by a fabric or only tissues. The helmet 1 may also include a retention system, including for example a jugular strap 4 and / or a headstop wedging system, not shown.

The helmet 1 is intended to wrap at least part of a skull that the helmet will protect.

The invention relates more specifically to the outer shell 2 obtained by injection.

The outer shell 2 is thus made by molding. Once injected, the outer shell forms an envelope surface S2, intended to substantially match the morphology of the skull of the user. The outer shell is therefore shaped volumetrically to cover part of the head.

The envelope surface S2 is delimited by a lower edge 23 forming a loop around the head. In this example, the lower edge is not included in a horizontal plane but is distributed over several horizontal floors.

The envelope surface may have a variable thickness or have a substantially constant thickness, i.e., the thickness is the same for at least 90% of the envelope area.

According to the invention, the injected outer shell comprises at least one thin portion 21 whose thickness e21 is less than or equal to 1.3 mm, preferably less than or equal to 1 mm. To lighten the part and allow it to deform further to dampen shocks, the thin portion 21 represents at least 25% of the envelope area S2. According to one embodiment, the thickness e21 is less than or equal to 1.3 mm, or even 1 mm, over at least 90% of the envelope surface. With a thin, substantially constant and uniform thickness over almost all of its envelope surface, the outer shell can be more easily implemented. Indeed, the molding is better and more homogeneous with a substantially constant thickness.

A main function of the helmet is to protect the skull in the event of a fall or impact with a projectile. In the helmet design, it turns out to be the top portion 22, that is, the portion extending from the top of the skull to a periphery of the skull passing through the temples of the skull , which is the most delicate to size in terms of depreciation.

The desired damping is obtained on the one hand by the inner cap and on the other hand, can be improved by the outer shell. Thus, the inner cap expanded material is mainly involved in damping. According to one embodiment of the invention, the outer shell has a thin, thin portion in this summit portion 22. This small thickness facilitates the deformation of the shell locally. As a result, the outer shell dissipates impact energy and is more involved in shock absorption.

In the example shown, the outer shell has a thickness e21 almost constant. The thickness e21 is less than or equal to 1.3 mm, or even less than 1 mm, in more than 90% of the envelope surface S2.

The outer shell is a first protection to external stresses. Protection against bad weather be it water, snow. It must therefore preferably have hydrophobic characteristics. In addition, it is a projectile protection. It must therefore preferably have a resistance to perforation. And, as we saw earlier, she can participate in the shock absorption. As a result, the material constituting the outer shell is adapted to meet these needs.

For example, the outer shell is made of one of the following materials: PU, ABS, PP or PC.

Traditionally, manufacturers use analogous materials to make the outer shells injected. However, the conventional molding technology that they use does not allow them to manufacture outer shells having thicknesses less than 2 mm. When the thickness is greater than 2 mm, the outer shell is relatively heavy and rigid. It participates to a much lesser extent in damping shocks.

For small thicknesses, less than 2 mm, the mold does not fill correctly and the piece leaves incomplete mold. In addition to appearance, the characteristics of the outer shell are compromised.

The invention proposes to use an outer shell having lower thicknesses than the conventional hulls of the state of the art in particular through a choice of material and / or a specific injection method.

According to one embodiment, the shell is made of a material having a very good fluidity in order to completely and correctly fill the mold. Such a material may be a material whose melt flow index (MVR) is greater than 8 cm ³ / 10min. This value is, for example, measured according to ISO 1133 with the following parameters 220 ° C / 10 kg. Thus, the judicious choice of a fluid material allows the realization of an outer shell having thicknesses less than or equal to at least 1.3 mm locally.

One of the difficulties in molding a shell having a thin thickness is to ensure a good filling of the mold before the material freezes. We have seen previously that the fluidity of the material already makes it possible to improve the filling of the mold. However, another means also facilitates the filling of the mold. This is to position the injection points appropriately.

Conventionally, the injection points of the outer shells are placed, inside the envelope S2, away from the lower edge 23. The thickness greater than 2 mm allows the material to flow properly to fill all the mold. The lower edge 23 is filled at the end of the injection phase. With a finer thickness, this conventional method would not fill the mold properly, especially at the bottom edge of the shell, because the material is likely to solidify before reaching the lower limit of the outer shell.

To overcome this filling problem, one embodiment consists in positioning at least one injection point 24 on a lower edge 23 of the outer shell. Locally, at this point of injection, the shell may include a slight extra thickness so that the material diffuses better. According to one embodiment, the shell comprises at least two injection points 24 located on its lower edge 23. These two injection points are placed symmetrically with respect to a vertical plane either sagittal median P or transverse median T. With two points injection, the filling is more balanced. Given the size of the outer shell, it may be preferable to have four injection points 24 at the lower edge 23, as shown in the figures. In this case, the four injection points are arranged so that each injection point has another injection point symmetrical with respect to a sagittal vertical plane P. Moreover, each injection point has another point of injection. injection substantially symmetrical with respect to a transverse vertical plane T. Due to the asymmetrical shape of the shell with respect to this transverse vertical plane T, the injection points may be slightly offset, hence this slight asymmetry between the points Injection with respect to the transverse vertical plane T. With four injection points 24 distributed around the periphery of the lower edge 23 of the shell, a very good filling of the mold and more particularly of the lower part of the shell is obtained. With this arrangement, each injection point makes it possible to fill a quarter of the lower part of the shell. The filling is significantly improved over a conventional method for a shell having a small thickness. To fill the upper part, in this example, the outer shell comprises an upper injection point 25.

To further improve the filling of the mold, the supply channel (s) 241 of the injection point or points 24 placed on the lower edge 23 of the shell are oriented substantially tangentially to the envelope surface at the lower edge. In other words, such a feed channel 241 is aligned with a direction extending the envelope surface S2 at the lower edge 23. This direction may be slightly offset relative to this tangent by an angle of plus or minus 30 degrees. where the orientation substantially tangentially to the envelope surface. In the example, the supply channels 241 are oriented in a vertical plane but they could be inclined. This orientation allows the material to flow better into the mold which facilitates filling in thin areas. The figure 3 illustrates one of the four power channels 241.

In our example, the feed channel of the top injection point 25, not shown, is also vertical.

The characteristics of the process described above contribute individually or in combination to improving the filling of the mold with a shell having a small thickness.

Thanks to the invention, it is possible to obtain an injected outer shell of small thickness, at least locally. By being injected, the shell has a very good finish requiring little or no recovery operations to obtain the desired quality. Moreover, the molding makes it easy to obtain reliefs or openings with a beautiful appearance. In addition, this reduction in thickness, at least local, allows to lighten the hull and therefore the weight of the helmet.

Indeed, the invention makes it possible to reduce the thickness of the shell by a factor of two or more. Instead of being greater than 2 mm, the thickness is less than 1.3 mm and preferably less than 1 mm. This allows to greatly reduce the weight of the hull. For example, a current shell ABS whose thickness is slightly greater than 2 mm weighs in the order of 250 grams while the ABS shell with a thickness of around 1 mm weighs more than 100 grams. In addition, the inner cap EPS with a density of 60 grams / liter weighs of the order of 100 grams. Thus, the outer shell is decisive in the weight of the helmet.

Another advantage of having a shell with a small thickness lies in the possibility of improving the damping properties of the helmet. If the hull is relatively rigid, as are the conventional hulls, there is little interaction between the outer shell and the inner cap in terms of damping. The outer shell contributes little to damping. The transfer of the shock to the inner cap is spread over a relatively large area. Conversely, with a thinner shell, it can further deform and act on the damping in combination with the inner cap. This construction facilitates the absorption of local shocks. Charge transfer is improved. The damping properties of the inner cap are better exploited. We can then consider reducing the density of the expanded material used for the inner cap to increase shock absorption. For example, one may consider using EPS having a density of 40 or 50 grams / liter.

To make a sports helmet from the outer shell 2 injected thin, it is generally assembled to the inner cap 3.

The assembly between these two parts can be done mainly by two known methods.

The first method is to fix the inner cap inside the shell by appropriate connecting means such as clips, fasteners, rivets, glue, tape, VELCRO hooks ... This can also be tightened during nesting.

The second method, called "in-mold" technology, consists in placing the injected outer shell inside a mold into which a material is injected to produce the inner cap. Thus, the inner cap is directly connected to the outer shell to form a single piece.

Alternatively, the helmet may be a combination of these two methods. For example, the helmet may comprise two separate parts: an injected shell is assembled on an inner cap so as to cover an upper outer portion of the inner cap. The inner cap further includes an additional outer layer covering a lower outer portion of the patch. This layer is affixed to the inner cap by an "in-mold" process, from a thermoformed plate.

In this example, the helmet is shown with arrangements for ventilation in the form of openings 26 in the outer shell 2 and air ducts dug in the inner cap 3. Alternatively, the helmet may not include openings ventilation.

The invention is not limited to these embodiments. It is possible to combine these embodiments.

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

REFERENCES

1-

Helmet

2-

Outer shell S2- Shell surface 21- Thin part e21- Thickness 22- Upright part 23- Bottom edge 24- Injection point 241- Supply channel 25- Top injection point 26- Opening

3-

Internal cap

4-

Chinstrap

Claims (8)

Helmet for sporting practice (1) comprising an injected outer shell (2) forming an envelope surface (S2) intended to be positioned on a skull, characterized in that
the outer shell comprises at least one thin portion (21) whose thickness (e21) is less than or equal to 1.3 mm, the thin portion (21) representing at least 25% of the envelope surface (S2). Helmet (1) according to claim 1, characterized in that the thin portion covers a top portion (22) extending from the top of the skull to a peripheral periphery of the skull passing through the temples of the skull. Helmet (1) according to one of the preceding claims, characterized in that at least 90% of the envelope surface has a thickness less than or equal to 1.3 mm. Helmet (1) according to one of the preceding claims, characterized in that it comprises an inner cap (3), distinct from the outer shell (2), the inner cap being fixed inside the outer shell. Helmet (1) according to one of the preceding claims, characterized in that the outer shell consists of a material whose melt volume index (MVR) greater than 8 cm ³ / 10min (according to ISO 1133 ). Helmet (1) according to one of the preceding claims, characterized in that the outer shell is made of one of the following materials: PU, ABS, PP or PC. Method for manufacturing a helmet (1) according to one of the preceding claims, characterized in that it comprises a step of injecting the outer shell by at least one injection point (24) located on a lower edge ( 23) of the outer shell. Manufacturing method according to the preceding claim characterized in that the supply channel (241) of the at least one injection point (24) is oriented substantially tangentially to the envelope surface (P2) at the lower edge (23).

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