Patent Application
20250031796
The present invention relates to the field of helmets with cellular energy-absorbing structures. In particular, the present invention relates to helmets using layered structures.
In the state of the art some helmet solutions using cellular energy-absorbing structures are known. These kinds of structures have excellent properties in terms of impact energy absorption with respect to traditional polymeric foam materials. Despite this, the foam allows to obtain fascinating shapes and is still easier to mould with respect to the cellular structures. Therefore, many solutions employing these kinds of energy-absorbing structures combine the use of foam liners and cellular structures.
An example in this sense is disclosed in the patent U.S. Pat. No. 10,834,987. This document relates to a helmet comprising a plurality of cellular liners that are retained within respective recesses of a polymer foam shell without the necessity of using additional fasteners or adhesive. Substantially, the cellular liner of this document is sized to fit snug within the recess and is retained within the recess as a friction fit with the shell or foam of the recesses. According to this document fasteners are useless and discouraged. Despite the cellular liner being retained in the foam shell, during an oblique impact to the helmet, the cellular liner slides over a barrier layer arranged on the polymer shell and simultaneously it in-plane compresses. Therefore, the risk that during an impact the cellular liner gets out the polymer shell is high and, in this case, the head of the wearer is exposed to serious risks.
Similarly to the previous prior art document, the patent EP3473122 relates to a solution wherein a foam liner configured to support a cellular insert and, during an impact, the foam liner acts as a stop that helps to prevent the insert from sliding out of the cycling helmet. In addition, this solution uses an insert cover which helps prevent the insert removal. This insert cover is arranged on the foam liner to traverse the entire interior perimeter of the helmet for protecting the user's head from the abrasive surface of the insert. Indeed, cellular energy absorbing structures can have interior edges that are somewhat abrasive and uncomfortable if in direct contact with skin. For this reason, the insert cover of this document is arranged only over the interface between the insert and the foam liner, to avoid this kind of problem.
In this solution, the insert cover is not a fastener used to lock the insert to the foam liner, but a system for improving the comfort of the helmet and preventing a manipulation of the helmet. Substantially, this solution limits the problem of the previously mentioned document U.S. Pat. No. 10,834,9872, but it does not avoid an insert leakage, because during an impact the insert pad in-plane compresses and deforms, reducing its size. Consequently, the peripheral containment is not enough to avoid the release of the cellular insert from the foam liner during an oblique impact, exposing the wearer to risks.
None of the available solutions provides helmets comprising cellular energy-absorbing inserts that are fastened to the shell of the helmet, guaranteeing a firm connection between shell and cellular inserts during an impact regardless of the shell shape. This firm connection is required in particular during an oblique impact and presently known solutions do not guarantee that the cellular energy-absorbing insert does not come disconnected from the shell, nullifying its advantages and exposing the wearer to serious risks.
Moreover, all available solutions disclose helmets having cellular energy-absorbing inserts spanning across the at least one vent of the helmet, which reduce or alter ventilation.
Furthermore, since cellular energy-absorbing materials are more expensive with respect to foams, none of the available solutions suggests minimizing the usage of cellular energy-absorbing inserts for realizing a cheaper helmet, without affecting their safety.
Finally, none of the available solutions simplify the helmet construction and assembly.
Said and other inconvenients of the state of the art are now solved by a helmet comprising: a shell, preferably having at least one vent; one or more inserts of a cellular energy-absorbing material; and one or more retainers crossing the one or more inserts from side to side and fixed to the shell at opposing sides of the insert for constraining it to the shell. The one or more retainers are shaped so as to laterally and inwardly trap the one or more inserts. Preferably the one or more inserts have a curved shape. Alternatively, the insert/s can have a flat shape. A helmet so conceived allows to connect the insert/s in a stable manner to the shell, avoiding any release of the insert/s during an impact event, in particular during an oblique impact to the helmet. Moreover, this helmet allows simplification of assembly and allows smaller cellular inserts with a consequent reduction in costs.
Advantageously, the one or more inserts can be arranged inside the shell so as to leave the at least one vent free. This kind of solution maximizes the ventilation of the wearer's head, without detriment to the level of protection provided by the helmet.
Preferably, one or more retainers can be fixed to the shell so as to not span across said at least one vent. In this way, the vents are completely free and no obstacles are present in the vents.
In particular, the one or more retainers can comprise a plurality of first connectors, preferably snap-pins, configured to reversibly engage respective second connectors, preferably snap-baskets, attached to the shell. These kinds of connectors allow a connection/disconnection of the retainer/s to the shell.
Advantageously, the cellular energy absorbing material of the one or more inserts can comprise a plurality of interconnected open cells configured to absorb energy by plastic deformation in response to a longitudinal compressive load applied to said cells. This kind of cellular material provides excellent results in terms of energy-absorption and is very light weight. Preferably each cell can comprise a tube having a sidewall and a longitudinal axis, and the cells are connected to each other through their sidewalls. This feature enables the production of a sheet of interconnected side-by-side cells.
In particular, at least part of the longitudinal axes of the cells can be normal to an inner surface of the shell over which the one or more inserts are arranged. This arrangement of cells maximizes the absorption of the normal component of an impact.
Preferably, the helmet can also comprise a low frictional layer arranged over the shell in correspondence of the one or more inserts. This layer allows a translation of the insert reducing translational and angular accelerations of the brain that can be very dangerous for the wearer's health. This feature contributes to improve the helmet behaviour of absorbing the tangential component of an impact.
Advantageously, the one or more retaining elements can support one or more connecting means, like Velcro coins, for connecting a comfort liner to the rest of the helmet. These connecting means allow a simple, stable and fast positioning/removal of the comfort liner in/from the helmet.
In particular, the one or more retainers can be deformable and can exhibit a bending stiffness that is comparable or less than the insert/s′ compressive stiffness. Due to this behaviour of the retainer/s, during an impact, the retainers do not act as rigid beams but simply follow the deformation of the insert/s without opposing resistance.
Advantageously, the shell can comprise a plurality of shoulders defining one or more places wherein respective one or more inserts are accommodated to prevent a global displacement of the respective insert. These shoulders allow to keep the insert in position both during the assembly and during the use of the helmet. In particular, in case of an oblique impact, the insert in-plane compresses and deforms against the shoulder/s, but it remains coupled to the shell thanks to the retainer/s.
Preferably, the inserts can be three or more and extend in a front-rear direction. At least one insert is arranged on a left-side of the shell, at least one insert is arranged on a right-side of the shell and at least one insert is arranged on a top-side of the shell. Left and right inserts allow to protect temporal lobes of the brain, while the top insert allows to protect frontal, parietal and occipital lobes.
Preferably, the shell is a deformable shell that can be made of a foam material, for having a cheaper helmet. Alternatively, the shell can comprise a lattice structure, preferably a 3D printed lattice structure that allows to achieve better energy-absorbing performances.
In this particular case, the shell can comprise longitudinal and transverse ribs arranged so as to form vents. This architecture of the shell maximizes the strength of the deformable shell and allows perspiration and air flow.
Advantageously, the helmet can also comprise an upper skin configured to cover at least in part an upper and outer surface of the shell, and/or a lower skin configured to cover at least in part a lower and outer surface of the shell. The upper skin contributes, together with the shell and the inserts, to absorb the energy of an impact. The lower skin allows a customization of the helmet and protects the shell from lateral/lower impacts.
In an embodiment, the shell can also comprise one or more recesses shaped for accommodating additional insert/s. These additional inserts contribute to the impact energy absorption.
In an alternative embodiment to the deformable shell, the shell can be a hard shell, that is rigid and more suitable for work helmets.
Advantageously, the shell can comprise multi-purpose connectors, typical on work helmets, and the at least one retainer can be configured to reversibly connect to the multi-purpose connectors. Since the multi-purpose connectors are typical of work helmet, with this characteristic the retainer/s and the insert/s can be fixed to the majority of work helmets in an intuitive and simple manner.
Preferably one of the retainer/s is a side retainer that can be substantially shaped like a ring so as to wrap at least a part of a wearer's head and to laterally and inwardly trap one or more corresponding lateral inserts. This side retainer, in addition to retain the lateral inserts, allows to easily fit the helmet on the wearer's head without additional liners.
More preferably one of the retainer/s is a top retainer that can be substantially shaped like a dome so as to fit with an apex of the wearer's head and to laterally and inwardly trap one corresponding top insert. This top retainer, in addition to retain the top insert, allows to have a surface on which the wearer's head lays, making the helmet more comfortable, easy to wear better ventilated.
Advantageously, the helmet can comprise only one retainer configured to trap one or more inserts. In this manner, with a single element is possible to improve the safety of the helmet and the manufacturing costs are reduced.
A particular version of the retainer can comprise a fixed part connected to the shell and a moveable part coupled to the fixed part through deformable means. This solution allows a relative movement of the moveable portion of the retainer with respect to the fixed part and therefore also with respect to the rest of the helmet. The deformable elements allow an absorption of this relative movement. This particular kind of retainer is configured to absorb shear forces due to inclined impacts hitting the shell.
These and other advantages will be better understood thanks to the following description of different embodiments of said invention given as non-limitative examples thereof, making reference to the annexed drawings.
In the drawings:
The following description of one or more embodiments of the invention refers to the annexed drawings. The same reference numbers indicate equal or similar parts. The object of the protection is defined by the annexed claims. Technical details, structures or characteristics of the solutions here-below described can be combined with each other in any suitable way.
With the reference number 1 is represented a helmet according to the present invention. In particular,
The main components of the helmet 1 are the shell 2, the insert/s 3 and the retainer/s 4, as shown in the figures. These components will be detailed in the following.
The helmets 1 of the present invention comprise a head retention system (not represented). This retention system is configured to maintain the helmet 1 over the head of the wearer.
In the first and second embodiments, the shell 2 is preferably a body made of a polymeric foam, like EPS (Expanded Polystyrene) or EPP (Expanded Polypropylene), thus a deformable shell 2. Alternatively, the shell 2 is a hard shell like that of the third, fourth and fifth embodiments. In a further alternative embodiment (not shown), the shell 2 comprises a lattice structure. In the first and second embodiments, the shell is deformable, while in the third embodiment the shell is more rigid.
This shell 2 has an outer surface that can be subdivided in an upper outer surface 12 and a lower outer surface 11, and an inner surface 17.
This shell 2 generally provides the overall size and appearance of the helmet, as shown in
The insert 3 comprises a cellular energy-absorbing material that performs better than traditional foam materials in terms of energy-absorption, in particular in terms of absorption of compressive impact energy.
The insert 3 is made of a plurality of interconnected open cells 16. These cells 16 are configured to absorb energy by plastic deformation in response to a longitudinal compressive load.
Each cell 16 comprises a tube having a sidewall and a longitudinal axis. The cells 16 are interconnected via their sidewalls.
Initially, the insert 3 is flat and subsequently is curved. The flat insert (not shown) is like a tile/brick of interconnected cells having parallel longitudinal axes. The flat insert is cut to the required dimensions and then is curved. The flat insert normally has a constant thickness.
The flat insert can be curved via thermoforming or manually if it has synclastic or monoclastic behaviours. The insert 3 can thus assume a single-curved shape or a double-curved shape.
The cells 16 of the insert 3 are preferably tubes. The tubes depicted in the figures have circular cross-sections. Alternatively, the cross-section of the cells/tubes 16 can be a square, a hexagon, a non-uniform hexagon, a re-entrant hexagon, a chiral truss, a diamond, a triangle or an arrowhead. In particular, the cross-section of the cells/tubes 16 can be shaped so that the insert 3 exhibits a monoclastic or synclastic behaviour. Alternatively, the cells 16 can be the cells of a lattice structure.
Almost all cells 16 of the inserts 3 have longitudinal axes that are normal to the inner surface 17 of the shell 2. In this way the energy absorption is improved.
The cells 16 can be welded to each other via their sidewalls. Alternatively, the cells 16 can be bonded by means of adhesive layers interposed between adjacent sidewalls. The cells 16 can be connected so as to minimize the gap between adjacent tubes. Alternatively, the cells 16 can be monolithically extruded or 3D printed so as to share sidewalls.
When the cells 16 have a circular cross-section, the outer diameter of the circular cross-section can range between 2.5 and 8 mm, and the wall thickness of said cells 16 can range between 0.05 and 0.3 mm. According to these dimensional values, the energy absorption of insert 3 is optimized. Furthermore, these values allow you to have a very light helmet 1.
The insert 3 has a thickness between 15 and 40 mm.
In a particular embodiment (not shown), the insert 3 can comprise an upper and/or lower sheet layer. Said sheet layer can be a polymeric fabric, or a film, firmly attached to the front edges of said open cells 16 through a heat-activated adhesive. When a load is applied, the fabric spreads the energy on a plurality of cells 16, even if the load is applied punctually. The heat-activated adhesive can be a thermoset polyester web film adhesive.
The inserts 3 are connected to the shell 2 by means of retainers 4.
The retainers 4 are shaped to follow the shape of the inner side of the insert/s 3.
These retainers 4 cross the inserts 3 where they are flatter, thus in a direction that is perpendicular to direction in which the insert 3 curves. Where the insert 3 is flatter, the retainers 4 can easily overlap and cross the inserts 3 from side to side for tying it to the shell 2. Moreover, the surface of contact between the portion of the retainer 4 crossing the insert 3 and the insert 3 itself is maximized. For example, in the first and second embodiments, the inserts 3 are curved in a front-back direction and almost flat in a left-right direction, therefore the retainers 4 cross the inserts 3 in a left-right direction.
If the insert 3 is not very curved, the retainer 4 can also run in all directions. In the third embodiment of
Each retainer 4 comprises means to connect it to the shell 2 in a reversible or irreversible manner.
Each retainer 4 is coupled to the shell 2 so that, for each insert 3, one coupling point lies on one side of the insert 3 and another coupling point lies on the other side of the insert 3. Each insert 3 is thus constrained to the shell 2 at two opposing sides via the retainer 4 that crosses it.
The retainers 4 are configured to not oppose resistance in case of an impact. For this reason, the retainers 4 are deformable and exhibit a stiffness in bending that is comparable to or inferior to the compressive stiffness of the inserts 3. In this way, in case of a compression of the helmet due to an impact, the retainers 4 do not act as rigid beams, and they follow the compressive deformation of the insert 3. The retainers 4 are preferably made of a polymer like nylon or polyethylene. Alternatively, the retainers 4 are made of an elastomeric material, so to exert a clamping force that pushes the insert/s 3 against the inner surface 17 of the shell 2.
With the term “opposite sides” or “opposing sides”, reference is made to the lateral sides of the insert 3.
With reference to the first embodiment of
The shape of the shell 2 can vary, indeed the overall shapes of the helmets of the two embodiments are different, as shown in
The inner side of the shell 2 is shaped so as to form shoulders 7, as shown in
In correspondence of said places 6, the shell 2 is thinner with respect to the rest of the helmet 1. On these thin portions of the shell 2, the inserts 3 are arranged.
The insert 3 is overlaid to one of these thin portions of the shell 2 and faces inwardly. The thin portions can have a thickness of 5-6 mm.
The inserts 3 are arranged in respective places 6 of the shell 2 and the shoulders 7 also facilitate the positioning of the inserts 3 during the helmet assembly. The shoulders 7 even provide geometrical constraints to lateral movements of the inserts 3.
The shell 2 so conceived has a less complex shape, in particular on its inner side. Therefore, if shell 2 is made of foam like that of first and second embodiments, the mould used for achieving this shape requires less pieces and consequently the manufacturing of this kind of shell 2 is quicker and cheaper.
The retainers 4 of first and second embodiments comprise snap-pins 13 that are configured to reversibly engage with corresponding snap-baskets 14. These snap-baskets 14 are preferably embedded in the foam of the shell 2, as shown in
Each retainer 4 has more snap-pins 13 and consequently the shell 2 has more snap-baskets 14. Each snap-pin 13 corresponds to a snap-basket 14.
As represented in
In the first embodiment, the inserts 3,3′ are five. Three inserts 3 are connected through retainers 4 while two additional inserts 3′ are accommodated in respective recesses 19 in the shell 2, as shown in
The inserts 3 of the first embodiment are arc-shaped slices that are bonded to the shell 2 through two retainers 4. One retainer 4 is arranged in the front portion of the helmet 1, while the second one is arranged in the central-rear portion of the helmet 1.
Each retainer 4 crosses more inserts 3, alternating portions connected to the shell 2 to portions overlapping and crossing the inserts 3.
Each retainer 4 is shaped to block the lateral and inward movements of the insert 3. Substantially, the retainer 4 overlaps in part the insert 3 both over the inner side and over the lateral sides. The portions of the retainer 4 flanked to the inserts' sides prevent lateral movements, acting as shoulders 4B able to keep in position the insert 3 once that the retainer 4 is fixed to shell 2. In a particular embodiment, the retainer/s 4 only prevent/s inward movements.
For this reason, the retainer 4 can be shaped like a squared-curve, as shown in
In an alternative embodiment (not shown), the retainer 4 is flat so as to prevent only inward movements. In this case, the height of the shoulders 7 are substantially equal to the thickness of the insert 3.
Normally, the thickness of the inserts 3 is higher than the height of shoulders 7, because they are elements that come into play before the shoulders 7 during an impact. Therefore, the retainers 4 have said zig-zag shape. Vice versa, if the shoulders 7 are flush with the inserts 3, the retainers 4 are flat elements. In this case, the retainer 4 only traps inwardly the one or more inserts 3.
As shown in
The inserts 3 are arranged in the shell 2 so as to leave the vents 5 free, as shown in
Also, the retainers 4 are arranged so as to not span across the vents 5. In this way, since both the inserts 3 and the retainers 4 fall outside the vents 5, the ventilation is maximized.
The second embodiment of
In the first embodiment, one insert 3 is arranged on a left-side of the shell 2 together with an additional insert 3′, and, in a symmetrical manner, one insert 3 is arranged on a right-side of the shell 2 together with an additional insert 3′. Finally, an insert 3 is arranged on a top-side of the shell 2 along a centerline.
In the second embodiment, two inserts 3 are arranged on the left side of the shell 2 and two inserts 3 are arranged on the right side of the shell 2. Two of said couples face the top portion of the helmet 1, while the other one faces the side portion of the helmet 1.
During an orthogonal impact, the cells 16 of the inserts 3 plastically buckle absorbing a great quantity of the impact energy. The rest of the impact is absorbed by the shell 2 and by the skins 9,10.
During an oblique impact to the helmet 1 the insert 3 slides over the shell 2, in particular when the shell 2 comprises a low frictional layer 8, and presses against one or more shoulders 7 of the shell 2. Therefore, the insert 3 in-plane compresses and deforms absorbing the tangential component of the oblique impact. Despite this deformation, the insert 3 remains in place thanks to the retainer/s 4.
The retainers 4 tie the inserts 3 to the shell 2 independently from their deformations. Therefore, the present solution is safer and more reliable than those known in the art. The inserts 3 can slide over the shell 2 without becoming disconnected from it.
The shell 2 can comprise a thin low frictional layer 8, for example a coating of a semi-rigid polymer. This low frictional layer 8 creates a barrier over which the insert 3 can slide. The low frictional layer is arranged directly over the inner surface 17 of the shell 2, in correspondence with the inserts 3, as shown in
As schematically shown in
The comfort liner 20 is connected to the rest of the helmet 1 through connecting means.
As
The Velcro coins 18 are attached through an adhesive layer to the retainers 4. In this way, the comfort liner 20 can be easily attached to the shell 2 and simultaneously under the inserts 3.
The third embodiment of
The work helmet 1 of the third embodiment has an outer hard shell, made of a rigid plastic, like ABS, HDPE or polypropylene, and an inner insert 3 arranged in the top area of the helmet 1.
The insert 3 is caged by a retainer 4 that crosses the insert 3 along perpendicular directions. In particular, the retainer 4 crosses the insert 3 in the front-back direction and in the left-right direction, but other directions are possible.
The retainer 4 is connected to the shell 2 at its ends. At each end, the retainer 4 has a first connector, that is a slot 13′, as shown in
The retainer 4 is shaped so as to cross the insert from side to side and it's shaped like a cage.
In this way, the lateral and inward movements of the insert 3 are prevented.
Normally, the work helmets are configured to protect the wearer from objects that fall from a height, so along a vertical direction. For this reason, the insert 3 is arranged in the top area of the helmet 1. For the same reason, the insert 3 is not subject to strong lateral movements, therefore, in this embodiment, the retainer 4 acts more as a trap for the insert 3.
Even in this embodiment, the retainer 4 can comprise Velcro coins (not shown) for connecting a comfort liner (not shown). Otherwise, the helmet 1 comprises a suspension harness system.
The helmet 1 of the third embodiment has an insert 3 arranged outside the vents 5, therefore the vents 5 are not obstructed by the insert 3.
Even in this case, the retainers 4 are softer than the insert 3, in order to not oppose resistance in case of a compression due to an impact.
With reference to
The shell 2 of the work helmet 1 of the fourth embodiment is similar in shape and composition to that of the third embodiment. Both shells 2 comprise multi-purpose connectors 21. Multi-purpose connectors 21 are sockets provided on the shell 2 to which several items can be connected. These sockets have standard dimension and shape so that items can be connected to the shell 2 in a simple and easy manner.
As shown in
The multi-purpose connectors 21 in
The helmet of the fourth embodiment comprises two retainers 4: a side retainer 4′ and a top retainer 4″.
The side retainer 4′, shown in
As shown in
The side retainer 4′ has a shape that appears as a ring in a top view like that of
The side retainer 4′ comprises connecting elements 23 for connecting the retention system (not shown) to the side retainer 4′. The retention system is of a known type, therefore is not herein described in detail.
The side retainer 4′ is configured to trap two inserts 3 respectively arranged on the left and right side of the helmet 1, as shown in
The helmet 1 of fourth embodiment also comprises a top retainer 4″ shown in
The dome-shaped portion 22 allows a simple and comfortable fit with any kind of head.
The end of said arms comprises a slot 13′, similar or equal to that of side retainer 4′, for connecting the top retainer 4″ to the shell 2. These slot 13′ are shaped so as to engage respective pins 14′ belonging to the shell 2. The rest of the arms of the top retainer 4″ are shaped so as to act as shoulders 4B for laterally trapping the insert 3, as shown in
The top retainer 4″ is configured to retain an insert arranged in a top area of the shell 2. In this way, the helmet 1 protects the user from masses falling onto the top of the helmet 1, thus from so called crown impacts.
The top and side retainers 4′,4″ of the fourth embodiment are connected to the shell 2 through common pins 14′, in this way the number of elements projecting towards the head of the user is minimized.
Since some kinds of work helmets are conceived for electrical workers or people who could come into contact with electricity, the shell 2 does not comprise vents 5. This kind of helmet (not shown) is equal to those of third and fourth embodiments except for the absence of vents 5.
The inserts 3 of a fourth embodiment are equal to those of previous embodiments. Despite all inserts 3 represented in the drawings are curved, even flat inserts 3 can be used for the same function, in same way and obtaining the same result.
In a fifth embodiment, shown in
As
The moveable part 4D of the retainer 4 is shaped so as to fit over the wearer's head. A retention system (not shown) helps to keep the helmet 1 stable on the wearer's head. In case of an oblique impact, the shell 2 together with the fixed parts 4C of the retainer 4 tends to rotate with respect to moveable part 4D of the retainer 4, mitigating the effects of the oblique impact on the wearer's head.
The moveable part 4D of the retainer 4 is also connected to the shell 2 via slots 13′. With respect to third and fourth embodiment, the pin 14′ of the shell 2 associated to said slots 13′ is thinner and the slots 13′ are wider, as shown in
As shown in
In this fifth embodiment, the inserts 3 are equal to those of fourth embodiment and they are constrained in the same way to the shell 2 through the retainer 4. Even the shell 2 is substantially the same of fourth embodiment.
Concluding, the invention so conceived is susceptible to many modifications and variations all of which fall within the scope of the inventive concept, furthermore all features can be substituted to technically equivalent alternatives. Practically, the quantities can be varied depending on the specific technical requirements. Finally, all features of previously described embodiments can be combined in any way, so as to obtain other embodiments that are not herein described for reasons of practicality and clarity.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21020568.8 | Nov 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/058669 | 9/14/2022 | WO |
