EP3130243A1

EP3130243A1 - Protective helmet

Info

Publication number: EP3130243A1
Application number: EP16001722.4A
Authority: EP
Inventors: Stefano Baracco
Original assignee: Individual
Current assignee: George TFE SCP
Priority date: 2015-08-04
Filing date: 2016-08-03
Publication date: 2017-02-15
Anticipated expiration: 2036-08-03
Also published as: ITUB20152822A1; EP3130243B1; ES2827246T3

Abstract

Protective helmet (1) comprising a shell (10) and a lattice structure (11), wherein said shell and said lattice structure are monolithically connected each other and configured so that a continuous network of interconnected air channels runs through the shell and the lattice structure to enable the passage of air from the external to the internal of the helmet.

Description

TECHNICAL FIELD

The present invention relates to a helmet, or a hard hat, realized with a shock resistant material, that can be used for sport or work activities for safeguarding the head against impacts.

BACKGROUND ART

In the state of the art several types of helmets exist: motorcycle helmets, competition car helmets, digger helmets, hard-hats, bike helmets, ski helmets, etc.
The present invention relates mainly to the helmets for vehicles having wheels, for example motorcycle or car, but can be also easily adapted to different contexts or uses.
The helmet for motorcycle and car, in particular those for competitions, need to be designed so to resist to shocks far exceeding those of other types of helmets, for example the hard-hats or bike helmets.
An helmet generally consists of:

a shell, or external cover, made of an hard material;
a protective padding, having its external side matching with the internal face of the shell, and being designed for receiving the head of a user;
a comfort padding for making the helmet much confortable when it's worn by the user;
a retention system, generally comprising a strap and a quick-release locking system.

Said shell gives to the helmet a specific shape and allows to protect the protective padding and the user against minor shocks, moreover it contains the paddings. The material of the shell can be a plastic or a composite material containing different types of fibers, such as glass or carbon fibers.
Said protective padding can be made with polymeric foams, generally Styrofoam, and it's used for absorbing the energy generated during a collision. The material of the protective padding, making itself smaller and compact, allows to absorb the energy of a big impact.
Said comfort padding can comprise pillows made of synthetic or natural material which adhere to the internal side of the protective padding. In this way, the head of the user is not in direct contact with the protective padding but with the comfort padding that is much comfortable.
The comfort padding has not a great thickness because the vane of the protecting padding wherein the head is received should not be bigger than the head itself.
Said retention system is used for maintaining the helmet in position on the head of the user and can comprise a regulation device for regulating the tightening of the helmet on the head.
Generally the retention system comprises two straps made of synthetic material firmly fixed to the shell and having a quick-release locking system similar to that of seat belts, thus with a female element connected to one end of a first strap and a male element connected to the end of a second strap and configured to engage the female element under the chin of the user. Since the material of the protective padding is designed to absorb the impacts for plastic deformation, once the padding is deformed in a certain zone, the re-use of the helmet would be dangerous for the user.
Actually the Styrofoam is the widely used material for absorbing the energy of an impact and it is used by the large part of helmet manufacturers.
The Styrofoam suffers the variation of temperature hot/cold and the humidity. Consequently the validity period of a protecting padding is generally not more than 5 years, regardless of the material of the shell.
For this reason, certain helmet manufacturers suggest to replace the helmet after a certain time period.
Furthermore, the overall dimensions of actual helmets are strictly related to the thickness of the protective padding.
The helmets for vehicles can be open or "jet", thus without a protection for the chin/jaw, or integral, thus having a structure configured to protect both the head and the face. Furthermore, the helmets can comprise a system for ventilating the head of the user.
Said ventilation system generally comprises some holes on the shell to permit the air to enter from outside, some channels realized in the protective padding, and some distribution zones of the air in the comfort padding.
In this way, a small part of the air that the helmet meets when the vehicle is moving, is delivered into the helmet for cooling the user head.
The ventilation systems known in the art cannot convey a large amount of air into the helmet. If big channels would be realized into the protective padding, the padding itself would be too weakened, making the helmet unsafe.
The same problem applies to the shell. Bigger holes than actual could be potential trigger points for fractures of the shell in case of impact.
For these reasons, the actual helmets are not confortable during the warm season.
When the ambient temperature is hot, the temperature inside the helmet significantly increases warming the user head.
Consequently, the ventilation system of actual helmets do not allow an appropriate air circulation between the ambient and the user head when the helmet is worn.
It's well-known in the state of the art to realize a protective helmet comprising at least a protective layer having an internal lattice structure obtained through melting of power material, as described in the document EP2525187 .
The cited document of the state of the art describes the possibility of realizing a portion of the internal padding of a helmet, preferably a military helmet, through the known technology named additive manufacturing.
Said document doesn't describe how the shell is connected or integrated with the internal lattice structure. In particular, this document doesn't explain how to convey the air from the external of the shell to the internal lattice structure in an efficient way.
Furthermore, said document describes only one 3D-printing process, which is particularly expensive and complex.
Finally, said document doesn't explain how the lattice of the internal structure can be arranged and configured to maximise the shock absorption.

SUMMARY

The above-identified drawbacks of the prior art are now overcome by a protective helmet comprising a shell and a lattice structure, wherein said shell and said lattice structure are monolithically connected each other and configured so that a continuous network of interconnected air channels runs through the shell and the lattice structure to enable the passage of air from the external to the internal of the helmet. The air channels being fluidly interconnected.
Advantageously said helmet allows to maximise the amount of air exchanged between external and internal of the helmet, and to increase the internal air recirculation into the lattice structure.
Said helmet can comprise a shell having a plurality of air transit channels running from the external side to the internal side of the shell.
These channels provide an improved transit of air through the shell and a better fluid communication between the shell and the lattice structure.
The lattice structure can be connected to the shell in several points of the internal surface of the shell.
Thanks to this connection between lattice structure and shell, the air transit from the external to the internal is improved. The lattice structure allows to distribute the air crossing the shell in a uniform way over the head of the user.
The front and rear openings of the shell allow a facilitated transit of the air through the matrix when movements occur.
The air enters through the openings of the shell, preferably the front openings, and then transits through the network of interconnected air channels until it reaches the internal of the helmet and the head of the user, from here the air continues to flow and exits through further openings of the shell, preferably positioned on the back side of the helmet.
The lattice structure can comprise a plurality of fibres interconnected each other to form a three-dimensional network and several cavities defined by said fibres. The cavities are connected each other to form said continuous network of air channels fluidly interconnected each other.
The air is free to circulate internally to the lattice structure.
An helmet structure extremely resistant, elastic and light with respect to the traditional helmets, can be achieved through the structure with fibers.
The fibers can be arranged and oriented according to a predetermined logic, for example in a radial direction with respect to a predetermined point internal to the helmet.
Alternatively, the fibers can have a random arrangement.
Said fibers can be straight or curve and their quantity, arrangement, positioning and direction can be selected to regulate the mechanical resistance, the lightness and the ventilation degree of the helmet.
The term fiber means any element of the lattice structure having a length considerably greater than its thickness, preferably at least 3 or 5 times.
The shell generally has a thickness that is greater than the thickness of the fibers of the matrix, to give an improved stiffness to the external layer and a greater lightness and flexibility to the lattice structure.
The lattice structure can be made of a rigid or partially flexible material depending on the use of the helmet.
The lattice structure extends from the shell to an internal cavity configured to receive the head of the user.
The lattice structure is the protective padding of the helmet and for this reason it has a certain thickness extending from the shell to the zone wherein the head is inserted.
This thickness, thus the radial extension of the lattice structure, allows to maximize the mechanical and aerodynamic properties of the lattice structure.
To make the helmet more confortable, it can comprise an internal padding positioned in the internal cavity.
The helmet can also comprise external covering means for lining and/or personalizing the shell. This covering means, that can be made of natural or synthetic fabric, make the helmet waterproof and can make the helmet more attractive from an aesthetical point of view.
In this way, the user can quickly and economically personalize his helmet.
Furthermore, during the cold and rainy days, the covering means can avoid the entrance of cold air or rain inside the helmet.
Preferably, the lattice structure and the shell are made with the same material, making the manufacturing process more quickly and economical. For example PLA, ABS, HIPS, nylon, HDPE, PC, aluminium, thermoplastics and photopolymers can be used. Examples of thermoplastics are PPSF/PPSU, PC, Ultem, Polypropylene o tetra polyurethane.
A second object of the present invention is a manufacturing method of an helmet comprising the step of three-dimensionally printing with a material which solidifies at room temperature a lattice structure and an external shell so that a continuous network of interconnected air channels runs through the shell and the lattice structure to enable the passage of air from the external to the internal of the helmet.
The three-dimensional printing, in one of its known forms, allows to create the net of the lattice structure and the shell without the use of complex and costly moulds, and allows to avoid complex manufacturing techniques like the thermal melting of a part of the object.
According to the present description, the term monolithic means that the lattice structure is connected to the shell and can't be separated by it, thus they are a single piece.
In particular, the external portion of the lattice structure is inseparably connected to the internal surface of the shell so to create the single piece.
This continue connection allows to avoid vibrations or detachments of the shell during the use of the helmet or during an impact.
These and other advantages will appear in more detail from the description, in the following, of a non-limiting embodiment with reference to annexed drawings.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings:

Fig. 1 shows a schematic sectional view of a protective integral helmet according to the present invention;
Fig.2 shows a schematic sectional view of a protective jet helmet according to the present invention;
Fig. 3 shows a schematic sectional view of a detail of the connection zone between shell and lattice structure;
Fig. 4 shows a schematic sectional view of a detail of the external side of a particular version of the shell;
Fig. 5 shows a schematic sectional view of the protective helmet according to the present invention with a specific emphasis to the air that transits internally to the helmet;
Fig. 6 shows a lateral and sectional view of five possible versions of the shell and lattice structure of the protective helmet.

DETAILED DESCRIPTION

The following description of exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The scope of the invention is defined by the appended claims.
Technical details, structures or characteristics of the here-below described solutions can be combined each other in any way.
To understand the idea underlying the present invention, reference to Fig. 1, 2, 3, 4, 5 and 6 may be done.
In particular, the Fig. 1 illustrates an integral helmet in according to the present invention, while Fig. 2 illustrates an open or "jet" helmet according to the present invention.
The present protective helmet 1 comprises a shell 10 and a lattice structure 11.
The shell 10 and the lattice structure 11 are monolithically connected each other. The two portions, shell 10 and lattice structure 11, are not realized in two pieces assembled together in a second moment by glueing or other connection process, but they are monolithic, thus realized in a single piece.
The shell 10 and the lattice structure 11 are made so to have inside of them a plurality of air channels fluidly connected each other, to enable the passage of air from the external to the internal of the helmet.
The air 30 is free to enter in the passages 25 of the shell 10 and to flow freely through the network of the lattice structure 11. In this way, the air 30 running through the shell 10 can easily reach the head of the user wearing the helmet 1 and providing an improved heat exchange between the user head and the external ambient, as shown in figure 5.
The air running through different paths from the external to the internal of the helmet represents the plurality of air channels fluidly interconnected each other.
The shell 10, as well as the lattice structure 11, covers entirely the head portion to be protected. In particular, the helmet 1 covers the head portions corresponding to the frontal, parietal, occipital, sphenoid and temporal of the user cranium. When the helmet is integral, also the jaw is covered.
The shell 10 has a thickness substantially uniform on the entire surface. The thickness of the shell 10 is comprised between 1 mm and 5 mm, preferably 3 mm.
The external shell 10 provides to the helmet 1 the required rigidity and allows to protect the lattice structure 11 from shocks of low/moderate intensity.
The shell 10 can have a reticular or mesh structure to allow the air flowing. The reticular or mesh structure can be curved, substantially smooth, and having a plurality of passages 25 which pass through the shell according to its thickness.
The reticular or mesh structure can interest only some portions of the shell 10, for example the frontal and rear portions, or involve the entire shell surface.
The reticular or mesh structure comprises a plurality of channels or passing through holes 25 which can have several shapes and sections. Preferably, the holes 25 have a size smaller than 3000 mm², preferably between 10 mm² and 500 mm², to allow an optimal transit of the air through the shell 10. The number of holes 25 is inversely proportional to the area of the holes themselves.
Alternatively, the shell 10 can be a housing having a plurality of passage channels or holes 25 for the air transit.
The arrangement of the passage holes 25 on the surface of the shell 10 can be uniform or optimized, thus with a large concentration in the front and rear of the helmet 1, to facilitate the entry and exit of air 30 during movement, as shown in figure 5.
Said passages 25 can be configured so to minimize the turbulences, the noise and the vibrations internally to the helmet. For this scope, the passages 25 of the shell 10 can have an entrance/exit substantially tangential to the external surface of the shell 10 so to optimize the aerodynamic of the helmet itself, as shown in figure 5.
The lattice structure 11 is a reticular three-dimensional structure having bulk portions, named fibers 26, which confer rigidity and flexibility to the structure and empty portions which confer lightness and allow the perspiration of the structure. The fibers 26 are elongated elements and can have several shapes.
The lattice structure 11 has in it a complex network of elements connected each other, said network substantially extends inside the whole volume of the lattice structure 11.
This network of the lattice structure 11 can be organized according to a random logic, like a marine sponge, or according to a predetermined logic, like a 3D network where all the 3D cells are equal.
The lattice structure 11, with respect to the well-known styrofoam structure, is empty in it and allows the circulation of the air in any direction.
With reference to the figures 6A, 6B, 6C, 6D and 6E, the organization of the lattice 11 can have different shapes. Preferably the elements (fibers 26) of the lattice structure 11 can have helicoidal shape (fig. 6A), zigzag shape (fig. 6B), circular shape (fig. 6C), wave shape (fig. 6D) or honeycomb shape (fig. 6E).
The shapes illustrated in figures 6 represent structures optimized to absorb the radial impacts in a efficient way. During an impact, the so arranged structures are able to collapse absorbing the impact.
The helix of the helical fiber 29 has a radially oriented axis. Likewise, the serpentine of the zigzag fiber 30 develops according to a substantially radial direction.
When the shape is circular, the reticular structure has in it a plurality of cylinders 31 (or spheres), which sectioned look circulars, arranged in contact each other and organized in parallel rows. Likewise, in case of honeycombs, the plurality of cells 32 having honeycomb shape are stacked each other to form the lattice structure and the stacks can be aligned in parallel each other. When the shape is waveform, the waves 33 of the lattice structure can be stacked each other so that the minimum peak of a wave is in contact with the maximum peak of the below-arranged wave. Alternatively, as shown in figure 6D, the waves are separated by perforated septa 34.
Furthermore, depending on the material used for the lattice structure 11, the latter can be more resistant and/or lighter than the know structure in Styrofoam.
The lattice structure 11 comprises internally a plurality of air channels continuously connected each other obtained through the joining of empty spaces of the lattice structure 11.
This network of channels allows the free flowing of the air in the lattice structure 11, removing any trace of humidity in the protective structure, and avoiding the degradation of the structure itself.
The three-dimensional network of the lattice structure 11 enables to avoid high temperatures of the protective structure during the hot periods of the year, when the sun's rays hits the shell and heats up the below protective material. Maintaining the temperature inside the lattice structure 11 more uniform the material can resist longer and can maintain its mechanical characteristics unaltered.
The three-dimensional network of the lattice structure 11 can comprise a plurality of fibers 26 interconnected each other. The space delimited by the fibers 26 represents a plurality of interconnected cavities and thus the network of interconnected air channels.
These fibers 26 can have random arrangements and directions or can run according to predetermined development logic.
The fibers 26 develop in several directions and cross them self with other fibers to reinforce the lattice structure 11.
For example, some fibers 26 can be oriented radially with respect to a predetermined internal point of the helmet, preferably with respect to the centre of mass.
In this way, the energy developed during the eventual impact applies on the fibers compressing them.
In an alternative embodiment, shown in fig. 3, the fibers 26 can be oriented at about 45° with respect to the internal surface of the shell to unleash efficiently the energy of an eventual impact.
The fibers of the lattice structure 11 can have uniform or variable thickness.
The elements of the network of the lattice structure 11, for example the fibers 26, are connected monolithically to the shell 20 in predetermined points of the inner surface of the shell 10.
Said predetermined points can be in the cross zones of the mesh of the shell 10 to maximize the mechanical efficiency of the helmet 1, as shown in figure n. 3.
The internal surface of the shell 10 represents the root from which the fibers 26 of the lattice structure 11 depart.
The solid connection of the shell 10 with the lattice structure 11 allows to maximize the helmet resistance and to elongate its life.
The shell 10 and the lattice structure 11 cannot detach each other. Furthermore, the connection between shell 10 and lattice structure 11 generates a fluid connection of the air channels that is more efficient and free of leaks.
The lattice structure 11 is configured to receive the user head, thus it has an internal cavity 14 sized according to the user head size.
The inner part of the lattice structure 11 can have a surface or internal wall 22, shown in figure 3, used to delimit internally and to protect the lattice structure itself.
Said internal surface 22 can have a plurality of air channels 23 similar to those of the shell 10. In figure 3 is shown a lattice structure 11 free of an surface or internal wall 22.
The lattice structure 11 runs from the internal surface of the shell 10 to said cavity 14.
To improve the comfort of the user, the internal cavity 14 can be layered with an internal padding 12, which can be made by one or more portions of a padded fabric or foam rubber.
This fabric is extremely breathable so that the air, which runs through the shell 10 and the lattice structure 11 easily, reaches the user head.
The helmet 1 can also comprise further padding zones facing to the back of the head 15 of the user and/or facing to the chin 16 of the user.
Furthermore, the helmet 1 can comprise a retainer system 13 of the helmet 1 to the user head. This retainer system 13 can be one of the several systems know in the art, for example the classic string that needs to be fixed below the user's jaw.
Since the helmet 1 comprises several air channels, in case of rain, the helmet could be potentially uncomfortable, because the water could filter through the structure of the helmet 1.
According to a first solution to avoid the water leaks through the shell 10, its holes 25 can be dimensioned so that the drop remains on the surface without penetrating in the holes 25. To obtain this effect, the holes have a diameter of about 0,5 mm, so that the droplet adheres for capillarity to the shell 10 without penetrates internally.
According to a second solution to avoid the water leaks through the shell 10, the external surface of the shell has bumps 37 protruding externally to surround the edges of the passages 35, like those of figure 4.
These bumps 37 avoid the water flowing on the external surface of the shell 10 to enter in the passages 35.
According to a third solution to avoid the water leaks through the shell 10, the external surface of the shell 10 comprises covering means for lining and/or personalizing the shell 10.
The covering means (not shown) can be a cap or a cover anchorable to the shell 10 to cover and to waterproof the shell 10 itself.
For example, during the cold season, it may be required to reduce the air flow through the shell 10 and consequently to insulate the user's head from the external ambient. At the same time, it may be necessary to stop the entry of water through the holes 25 of the shell 10 in case of rain. By means of the covering means, the air and/or water do not reach the user head through the network of interconnected air channels of the helmet 1 because said covering means acts as a shield.
Said covering means can comprise waterproof or windscreen fabrics and cover entirely the shell 10. Said waterproof or windscreen fabrics can be selected between said known in the art, for example waxed fabrics or fabrics comprising Teflon^®.
Said covering means can be anchored to the shell 10 by means of clips, Velcro, rubber bands or by means of any know quick connector of flexible structures to rigid structures that is able to resist to wet conditions.
In a particular embodiment, the present helmet comprises a fan to force the air into the helmet and/or a heating system to heat the air entering in the helmet. Said systems can be electrical.
In a further particular embodiment of the helmet 1, the network of the lattice structure 11 can be filled with a material so to obtain special functions. The lattice structure 11 can be filled with a dense substance, for example a rheopectic substance (not shown). The rheopectic substance, or not-Newtonian fluid, can be poured in the matrix 11 through the holes of the shell 10 and/or of the lattice structure 11 itself.
The rheopectic substances or not-Newtonian fluid are well-known fluids having variable viscosity depending on the shear stresses applied on them. Essentially, they are fluids which at rest are substantially dense and become rigid if stressed with a sudden mechanical stress. Filling the lattice structure 11 with a not-Newtonian fluid, the helmet becomes extremely resistant to extreme hits, for example to hits of bullets or blunt objects.
The mechanical resistance of the not-Newtonian fluid cooperates with the mechanical resistance of the lattice structure 11. In this embodiment of the helmet, only few channels of the shell 10 and of the lattice structure 11 are dedicated to the air transit.
The shock resistance of the non-Newtonian fluid is now added to the mechanical resistance of the lattice matrix 11. In this particular embodiment, only few channels of the shell 10 and lattice matrix 11 can be dedicated to the air transit.
This particular kind of helmet is also particularly appropriate for military helmets.
The manufacturing of a single piece consisting of the shell 10 and the lattice structure 11 can be simplified by means of the three-dimensional printing.
A second object of the present invention is a manufacturing method of an helmet comprising the step of three-dimensionally printing with a material which solidifies at room temperature a lattice structure 11 and an external shell 10 so that a continuous network of interconnected air channels runs through the shell 10 and the lattice structure 11 to enable the passage of air from the external to the internal of the helmet 1.
During the three-dimensional printing, the lattice structure 11 and the shell 10 are printed contemporary and in any case they are printed so to be monolithic.
The term three-dimensional printing means every technical process for manufacturing a three-dimensional component overlapping subsequent layers of material using an electronic control. Known examples of three-dimensional printing processes that can used for this scope are:

direct metal laser sintering (DMLS), electron-beam melting (EBM), selective laser melting (SLM), selective heat sintering (SHS) or selective laser sintering (SLS), which allow to print titan, cobalt, chrome, aluminium alloys or thermoplastics or ceramic powders, through a selective melting of the powders/grains of said materials;
Stereolithography (SLA) or Digital Light Processing (DLP) which allow to print photopolymers by means of a intense light;
Fused deposition modelling (FDM) or Fused Filament Fabrication (FFF), which through the extrusion allow to print thermoplastics (for example PLA, ABS, HIPS, Nylon), HDPE or eutectic metals;
Robocasting, which through extrusion allows to print ceramic materials, metallic alloys or composite materials.

Preferably can be used the 3D methodology of layer-by-layer type. It's furthermore preferable the use of a powder bed 3D printer.
Particularly preferable is the methodology known with the name of selective laser melting which allows to realize three-dimensional objects, layer-by-layer, starting from powders. These technologies allow to realize the element consisting of the helmet 10 and the lattice structure 11 independently from the shape of the shell 10 and the internal arrangement of the lattice structure 11.
By means of one of the above-mentioned 3D printing technologies, the single-piece consisting of the shell 10 and the lattice structure 11 is realized in a single manufacturing phase, thus without further manufacturing steps. The removal of the powder and burrs, and the superficial finishing can be realized on the single-piece after the printing.
The single-piece, being printed in a continuous manner, has no tears or partial ruptures that can become potential breaking points and consequently increasing the fragility of the helmet 1. In a particular version of the present method, the helmet can be tailored on the user's head. The method can include the further step of preliminary scan the shape of the user's head by means of a three-dimensional scanner, preferably a light scanner or a laser scanner.
Once the head of the user (its shape) is scanned, the helmet, in particular the surface of the internal cavity of the lattice structure 11, is realized accordingly, proportionally and likeness the scanned shape. In this way, a tailored helmet is achieved. The right proportions to apply to improve the wearability are fixed by international rules.
Thereby, it is clear that the device so conceived can be susceptible of various modifications and variations, all covered by the scope of the invention; furthermore all the details are replaceable by technically equivalent elements. In practice, the materials used and the dimensions may be any according to the technical requirements.
Finally, here-below are mentioned some advantageous embodiments:

Protective helmet 1 comprising a shell 10 and a lattice structure 11, wherein said shell 10 and said lattice structure 11 are monolithically connected each other and configured so that a continuous network of fluidly interconnected air channels runs through the shell 10 and the lattice structure 11 to enable the passage of air from the external to the internal of the helmet 1.
Manufacturing method of an helmet 1 comprising the steps of: scanning the shape of the head of a user by means of a three-dimensional scanner; three-dimensionally printing with a material which solidifies at room temperature a lattice structure 11 and an external shell 10 so that a continuous network of fluidly interconnected air channels runs through the shell 10 and the lattice structure 11 to enable the passage of air from the external to the internal of the helmet 1 and so that the inner of the helmet 1 has a shape proportioned to the scanned shape.
Manufacturing method of an helmet 1 according to the present invention, wherein the step of three-dimensionally printing the lattice structure 11 and the shell 10 is performed using a layer-by-layer printing.
Protective helmet 1 according to the present invention, wherein the shell 10 has a thickness larger than the thickness of the fibers of the lattice structure 11.
Protective helmet 1 according to the present invention, wherein at least a part of the air channels is filled with a not-Newtonian fluid.
Protective helmet 1 according to the present invention, wherein the elements of the lattice structure 11 have a helicoidal, zigzag, circular, honeycomb or wave shape.
Protective helmet 1 according to the present invention, wherein the air transit channels 25 are arranged only in the frontal and the rear portions of the shell 10.
Protective helmet 1 according to the present invention, wherein the entire portion of the lattice structure 10 facing externally is indivisibly connected to the internal surface of the shell 10.

Claims

Protective helmet (1) comprising a shell (10) and a lattice structure (11), wherein said shell (10) and said lattice structure (11) are monolithically connected each other and configured so that a continuous network of interconnected air channels runs through the shell (10) and the lattice structure (11) to enable the passage of air from the external to the internal of the helmet (1).
Protective helmet (1) according to the previous claim, wherein the shell (10) comprises a plurality of air transit channels (25) running from the external side to the internal side of the shell (10).
Protective helmet (1) according to claim 1 or 2, wherein the lattice structure (11) is connected to the shell (10) through several points of the internal surface of the shell (10).
Protective helmet (1) according to any of preceding claims, wherein the lattice structure (11) comprises a plurality of fibres (26) interconnected each other to form a three-dimensional network and cavities defined by said fibres (26).
Protective helmet (1) according to the previous claim, wherein the positioning and the direction of fibres (26) follow a predetermined logic or alternatively a random logic.
Protective helmet (1) according to claim 4 or 5, wherein fibres (26) are radially oriented with respect to a predetermined point internal to the helmet (1), preferably with respect to the barycentre of the helmet (1).
Protective helmet (1) according to any of preceding claims, wherein the lattice structure (11) runs form the shell (10) to an internal cavity (14) configured to receive a part of the user head, and wherein an internal padding (12) is positioned on the internal side of the lattice structure (11).
Protective helmet (1) according to any of preceding claims, comprising external covering means for lining and/or personalizing the shell (10).
Protective helmet (1) according to any one of claims 2 to 7, wherein the external surface of the shell (10) comprises prominences (37) protruding outwardly to surround the edges of the air transit channels (35).
Manufacturing method of an helmet (1) comprising the step of three-dimensionally printing with a material which solidifies at room temperature a lattice structure (11) and an external shell (10) so that a continuous network of interconnected air channels runs through the shell (10) and the lattice structure (11) to enable the passage of air from the external to the internal of the helmet (1).