TECHNICAL FIELD
[0001] 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
[0002] 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.
[0003] 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.
[0004] 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.
[0005] A helmet generally consists of:
- a shell, or external cover, made of a 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 comfortable when it's worn by the user;
- a retention system, generally comprising a strap and a quick-release locking system.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] For this reason, certain helmet manufacturers suggest to replace the helmet after
a certain time period.
[0015] Furthermore, the overall dimensions of actual helmets are strictly related to the
thickness of the protective padding.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] For these reasons, the actual helmets are not comfortable during the warm season.
[0022] When the ambient temperature is hot, the temperature inside the helmet significantly
increases warming the user head.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] Furthermore, said document describes only one 3D-printing process, which is particularly
expensive and complex.
SUMMARY
[0028] 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.
[0029] 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.
[0030] These channels provide an improved transit of air through the shell and a better
fluid communication between the shell and the lattice structure.
[0031] The lattice structure can be connected to the shell in several points of the internal
surface of the shell.
[0032] 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.
[0033] The front and rear openings of the shell allow a facilitated transit of the air through
the matrix when movements occur.
[0034] 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.
[0035] 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.
[0036] The air is free to circulate internally to the lattice structure.
[0037] A helmet structure extremely resistant, elastic and light with respect to the traditional
helmets, can be achieved through the structure with fibers.
[0038] 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.
[0039] Alternatively, the fibers can have a random arrangement.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] The lattice structure can be made of a rigid or partially flexible material depending
on the use of the helmet.
[0044] The lattice structure extends from the shell to an internal cavity configured to
receive the head of the user.
[0045] 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.
[0046] This thickness, thus the radial extension of the lattice structure, allows to maximize
the mechanical and aerodynamic properties of the lattice structure.
[0047] To make the helmet more comfortable, it can comprise an internal padding positioned
in the internal cavity.
[0048] 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.
[0049] In this way, the user can quickly and economically personalize his helmet.
[0050] Furthermore, during the cold and rainy days, the covering means can avoid the entrance
of cold air or rain inside the helmet.
[0051] 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.
[0052] A second object of the present invention is a manufacturing method of a 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.
[0053] 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.
[0054] 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.
[0055] 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.
[0056] This continue connection allows to avoid vibrations or detachments of the shell during
the use of the helmet or during an impact.
[0057] 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
[0058] 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
[0059] 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.
[0060] Technical details, structures or characteristics of the here-below described solutions
can be combined each other in any way.
[0061] To understand the idea underlying the present invention, reference to Fig. 1, 2,
3, 4, 5 and 6 may be done.
[0062] 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.
[0063] The present protective helmet 1 comprises a shell 10 and a lattice structure 11.
[0064] 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.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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 mm
2, preferably between 10 mm
2 and 500 mm
2, 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.
[0074] Alternatively, the shell 10 can be a housing having a plurality of passage channels
or holes 25 for the air transit.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] 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.
[0081] 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).
[0082] 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.
[0083] 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.
[0084] 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.
[0085] 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.
[0086] 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.
[0087] 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.
[0088] 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.
[0089] These fibers 26 can have random arrangements and directions or can run according
to predetermined development logic.
[0090] The fibers 26 develop in several directions and cross them self with other fibers
to reinforce the lattice structure 11.
[0091] 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.
[0092] In this way, the energy developed during the eventual impact applies on the fibers
compressing them.
[0093] 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.
[0094] 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.
[0095] 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.
[0096] The internal surface of the shell 10 represents the root from which the fibers 26
of the lattice structure 11 depart.
[0097] The solid connection of the shell 10 with the lattice structure 11 allows to maximize
the helmet resistance and to elongate its life.
[0098] 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.
[0099] 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.
[0100] 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.
[0101] 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.
[0102] The lattice structure 11 runs from the internal surface of the shell 10 to said cavity
14.
[0103] 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.
[0104] 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.
[0105] 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.
[0106] 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.
[0107] 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.
[0108] 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.
[0109] 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.
[0110] These bumps 37 avoid the water flowing on the external surface of the shell 10 to
enter in the passages 35.
[0111] 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.
[0112] 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.
[0113] 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.
[0114] 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®.
[0115] 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.
[0116] 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.
[0117] 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.
[0118] 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.
[0119] 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.
[0120] 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.
[0121] 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.
[0122] This particular kind of helmet is also particularly appropriate for military helmets.
[0123] 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.
[0124] A second object of the present invention is a manufacturing method of a 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.
[0125] 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.
[0126] 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.
[0127] Preferably can be used the 3D methodology of layer-by-layer type. It's furthermore
preferable the use of a powder bed 3D printer.
[0128] 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.
[0129] 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.
[0130] 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.
[0131] 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.
[0132] In a particular version of the present method, the helmet can be tailored on the
user's head.
[0133] 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.
[0134] 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.
[0135] 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 as defined by the claims.
In practice, the materials used and the dimensions may be any according to the technical
requirements.