HELMET

Abstract

Helmet (1) comprising: a shell (2): one or more inserts (3) of a cellular energy-absorbing material: one or more retainers (4) crossing the one or more inserts (3) from side to side and fixed to the shell (2) at opposing sides of each insert (3) for constraining it to the shell (2), the one or more retainers (4) are shaped so laterally and inwardly trap the one or more inserts (3).

Claims

1. A helmet comprising: a shell; 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 each 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.

2. The helmet according to claim 1, wherein the one or more inserts have a curved shape.

3. The helmet according to claim 1, wherein the shell comprises at least one vent.

4. The helmet according to claim 3, wherein the one or more inserts are arranged inside the shell so as to leave said at least one vent free.

5. The helmet according to claim 3, wherein one or more retainers are fixed to the shell so as to not span across said at least one vent.

6. The helmet according to claim 1, wherein the one or more retainers comprise a plurality of first connectors configured to reversibly engage with respective second connectors attached to the shell.

7. The helmet according to claim 1, wherein the cellular energy absorbing material of the one or more inserts comprises a plurality of interconnected open cells configured to absorb energy by plastic deformation in response to a longitudinal compressive load applied to said cells.

8. The helmet according to claim 7, wherein at least part of the longitudinal axes of the cells are normal to an inner surface of the shell on which the one or more inserts are arranged.

9. The helmet according to claim 1, also comprising a low frictional layer arranged over the shell in correspondence to the one or more inserts.

10. The helmet according to claim 1, wherein the one or more retaining elements support one or more connecting means, like Velcro coins, for connecting a comfort liner to the rest of the helmet.

11. The helmet according to claim 1, wherein the one or more retainers are deformable and exhibit a bending stiffness that is comparable to or less than the compressive stiffness of the insert/s.

12. The helmet according to claim 1, wherein the shell comprises a plurality of shoulders defining one or more places wherein respective one or more inserts are accommodated to prevent a global lateral displacement of the respective insert.

13. The helmet according to claim 1, wherein the inserts are three or more and extend in a front-back 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.

14. The helmet according to claim 1, wherein the shell is a deformable shell made of a foam material or comprising a lattice structure.

15. The helmet according to claim 14, wherein the shell comprises longitudinal and transverse ribs arranged to form vents.

16. The helmet according to claim 14, also comprising 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.

17. The helmet according to claim 14, wherein the shell comprises one or more recesses shaped for accommodating additional insert/s.

18. The helmet according to claim 1, wherein the shell is a hard shell.

19. The helmet according to claim 18, wherein the shell comprises multi-purpose connectors to which at least one retainer is configured to reversibly connect.

20. The helmet according to claim 18, wherein a side retainer is substantially ring-shaped 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.

21. The helmet according to claim 1, wherein a top retainer is substantially dome-shaped so as to fit with an apex of the wearer's head and to laterally and inwardly trap one corresponding top insert.

22. The helmet according to claim 1, wherein the retainer is only one and is configured to trap one or more inserts.

23. The helmet according to claim 1, wherein the retainer comprises a fixed part connected to the shell and a moveable part coupled to the fixed part through deformable means.

Description

DRAWINGS DESCRIPTION

[0032] In the drawings:

[0033] FIG. 1 shows an isometric view of a first embodiment helmet according to the present invention viewed from below;

[0034] FIG. 2 shows a top view of a first embodiment helmet according to the present invention;

[0035] FIG. 3 shows a side view of a first embodiment helmet according to the present invention;

[0036] FIG. 4 shows a bottom exploded view of a first embodiment helmet according to the present invention;

[0037] FIG. 5 shows a detailed view of the connectors of the helmet according a first embodiment of the present invention;

[0038] FIG. 6 shows an isometric bottom view of a first embodiment helmet according to the present invention wherein the inserts are removed;

[0039] FIG. 7 shows a top view of a second embodiment helmet of the present invention;

[0040] FIG. 8 shows a front view of a second embodiment helmet of the present invention;

[0041] FIG. 9 shows a side view of a second embodiment helmet of the present invention;

[0042] FIG. 10 shows a bottom view of a second embodiment helmet of the present invention;

[0043] FIG. 11 shows longitudinal cross-sectional view of the helmet according to the second embodiment;

[0044] FIG. 12 shows an exploded view of a second embodiment helmet according to the present invention;

[0045] FIG. 13 shows a bottom view of a third embodiment helmet according to the present invention;

[0046] FIG. 14 shows an exploded view of a third embodiment helmet according to the present invention;

[0047] FIG. 15 shows longitudinal cross-sectional view of a third embodiment helmet according to the present invention;

[0048] FIG. 16 shows a detailed view of the connectors of a third embodiment helmet according to the present invention;

[0049] FIG. 17 shows an isometric bottom view of a fourth embodiment helmet according to the present invention;

[0050] FIG. 18 shows a transversal cross-sectional view of the fourth embodiment helmet according to the present invention;

[0051] FIG. 19 shows a longitudinal cross-sectional view of the fourth embodiment helmet according to the present invention;

[0052] FIG. 20 shows a cross-sectional view made in correspondence of the multi-purpose connector of the shell of the fourth embodiment helmet according to the present invention;

[0053] FIG. 21 shows a top view of the side retainer of the fourth embodiment helmet according to the present invention;

[0054] FIG. 22 shows an isometric top view of the side retainer of the fourth embodiment helmet according to the present invention;

[0055] FIG. 23 shows an isometric top view of the top retainer of the fourth embodiment helmet according to the present invention;

[0056] FIG. 24 shows an isometric top view of the top and side retainers of the fourth embodiment helmet according to the present invention;

[0057] FIG. 25 shows an isometric top view and a detailed view of a particular retainer according to the present invention;

[0058] FIG. 26 shows a schematic transversal cross-section view of a fifth embodiment helmet comprising a retainer having fixed and moveable parts.

DETAILED DESCRIPTION

[0059] 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.

[0060] With the reference number 1 is represented a helmet according to the present invention. In particular, FIGS. 1-6 depict a first embodiment of the helmet, FIGS. 7-12 depict a second embodiment of the helmet, FIGS. 13-16 depict a third embodiment of the helmet, FIGS. 17-20 depict a third embodiment of the helmet and FIG. 26 depicts a fifth embodiment.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] This shell 2 generally provides the overall size and appearance of the helmet, as shown in FIGS. 12 and 14.

[0066] 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.

[0067] 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.

[0068] Each cell 16 comprises a tube having a sidewall and a longitudinal axis. The cells 16 are interconnected via their sidewalls.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The insert 3 has a thickness between 15 and 40 mm.

[0076] 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.

[0077] The inserts 3 are connected to the shell 2 by means of retainers 4.

[0078] The retainers 4 are shaped to follow the shape of the inner side of the insert/s 3.

[0079] 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.

[0080] If the insert 3 is not very curved, the retainer 4 can also run in all directions. In the third embodiment of FIGS. 13-16, the retainer 4 crosses the insert 3 in the direction wherein the insert 3 is flatter, thus the left-right direction of the helmet 1 and in the direction wherein the insert 3 has a bigger curvature, thus the front-back direction of the helmet 1.

[0081] Each retainer 4 comprises means to connect it to the shell 2 in a reversible or irreversible manner.

[0082] 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.

[0083] 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.

[0084] With the term opposite sides or opposing sides, reference is made to the lateral sides of the insert 3.

[0085] With reference to the first embodiment of FIGS. 1-6, the shell 2 comprises a plurality of ribs 15 that are arranged longitudinally and transversally. The longitudinal ribs 15L cross the transverse ribs 15T. On the upper portion of the helmet 1, said longitudinal and transverse ribs 15L,15T form a sort of mesh, and the empty spaces of this mesh define the vents 5 of the helmet 1, as shown in FIGS. 2,3 and 6. The same architecture is present in the second embodiment, as shown in FIGS. 7,8,9 and 12.

[0086] The shape of the shell 2 can vary, indeed the overall shapes of the helmets of the two embodiments are different, as shown in FIGS. 3 and 9.

[0087] The inner side of the shell 2 is shaped so as to form shoulders 7, as shown in FIGS. 4, 5, 6, 11. The shoulders 7 are arranged so as to define at least a place 6, thus a zone/portion, wherein respective insert 3 can be arranged. The shoulders 7 can be niches or protrusions of the shell 2, as shown in FIG. 6. A place 6 is defined by neighbour shoulders 7.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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 FIGS. 5 and 11. When the snap-pins 13 enter in respective snap-baskets 14, the retainer 4 remains firmly connected to the shell 2. Vice versa, the snap-pins 13 can be extracted from the snap-baskets 14 for detaching the retainer 4. Alternatively, the first connectors and the second connectors are designed to provide a permanent and irreversible connection.

[0093] 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.

[0094] As represented in FIG. 1, 4, 6, 10, 11, the retainers 4 run in a transverse direction, while the inserts 3 develop in a longitudinal direction.

[0095] 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 FIGS. 4 and 6. These additional inserts 3 are shaped so to be flush with the inner surface 17 of the shell 2, when they are accommodated in said recesses 19.

[0096] 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.

[0097] Each retainer 4 crosses more inserts 3, alternating portions connected to the shell 2 to portions overlapping and crossing the inserts 3.

[0098] 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.

[0099] For this reason, the retainer 4 can be shaped like a squared-curve, as shown in FIG. 4.

[0100] 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.

[0101] 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.

[0102] As shown in FIG. 12, the helmet 1 also comprises an upper skin 9 which lies on an upper and outer surface 11 of the shell 2 and a lower skin 10 which lies on a lower and outer surface 12 of the shell 2.

[0103] The inserts 3 are arranged in the shell 2 so as to leave the vents 5 free, as shown in FIGS. 7, 8, 10. The vents 5 are free if observed frontally, as the top vents of FIG. 7.

[0104] 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.

[0105] The second embodiment of FIGS. 8-12 is substantially equal to the first embodiment of FIGS. 1-7 with the exception that first embodiment has five inserts 3,3 of which two encased in the shell 2 and three retained through retainers 4, while the second embodiment has four inserts 3 all retained through retainers 4. So, all features of the first embodiment are valid also for the second embodiment.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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 FIG. 11.

[0112] As schematically shown in FIG. 1, the helmet 1 comprises a comfort liner 20, that is represented through a transparent grey portion that covers the area wherein the shell 2 and the inserts 3 are arranged, except those portions having vents 5.

[0113] The comfort liner 20 is connected to the rest of the helmet 1 through connecting means.

[0114] As FIG. 1 depicts, each retainer 4 comprises more Velcro coins 18 arranged on the portions crossing the inserts 3. The hooks of Velcro coins 18 inwardly protrude from these portions of the retainers 4 and easily connect to the synthetic/natural fabric of the comfort liner 20.

[0115] 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.

[0116] The third embodiment of FIGS. 13-16 is a work helmet 1, while the helmets depicted in FIGS. 1-12 are bike helmets 1.

[0117] 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.

[0118] 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.

[0119] 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 FIG. 16. Vice versa, the shell 2 comprises second connectors, that in this case are pins 14 protruding from the shell 2. The shell 2 also comprises multi-purpose connectors 21.

[0120] The retainer 4 is shaped so as to cross the insert from side to side and it's shaped like a cage.

[0121] In this way, the lateral and inward movements of the insert 3 are prevented.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] With reference to FIGS. 17-20, the fourth embodiment of the present invention is a work helmet 1.

[0127] 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.

[0128] As shown in FIG. 20, the multi-purpose connector 21 comprises a pin 21. This pin 21 is configured to cooperate with a plug 4A of the retainer 4. The plug 4A is shaped so as to enter in the multi-purpose connector 21 and, when the plug 4A reaches a blocking position as shown in FIG. 20, a tab of the plug 4A abuts against the pin 21 for realizing a reversible fastening.

[0129] The multi-purpose connectors 21 in FIG. 17-19 are four but they can even be more or less.

[0130] The helmet of the fourth embodiment comprises two retainers 4: a side retainer 4 and a top retainer 4.

[0131] The side retainer 4, shown in FIG. 21,22,24, comprises plugs 4A arranged peripherally and shaped so as to enter and engage the multi-purpose connectors 21 of the shell 2. The side retainer 4 also comprises slots 13 for fixing it to other portions of the shell 2. For example, the retainer 4 of FIG. 21,22 comprises slots 13 that are used to connect it to the front and top portions of the shell 2. Slots 13 and plugs 4A are used to constrain the inserts 3 to the shell 2. When the inserts 3 are constrained to the shell 2, slots 13 and plugs 4A lie at opposing side of the inserts 3. Slots 13 engage pins 14 belonging to the shell 2. The slots 13 and pins 14 are kind of connectors for realizing a connection between the shell 2 and the retainer 4, but one of ordinary skill in the art will recognize that many other types of connecting means can be employed. For example, the retainer 4, the side retainer 4 and/or the top retainer 4 can be connected to shell 2 through screw/s, rivet/s, welding, or adhesives.

[0132] As shown in FIG. 21,22,24, the side retainer 4 comprise shoulders 4B for keeping in position the insert 3 once the side retainer 4 is fixed to shell 2. These shoulders 4B create abutments that avoid lateral displacement of the insert 3.

[0133] The side retainer 4 has a shape that appears as a ring in a top view like that of FIG. 21. This shape allows the side retainer 4 to wrap the side of the wearer's head. In this way, the helmet 1 protects the user from hitting his head on the ground. The fact of absorbing energy of so called off crown impacts with energy-absorbing insert having high load absorption capacity is particularly innovative in the field of industrial/work helmets.

[0134] 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.

[0135] 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 FIGS. 17-19. Right and left inserts 3 end in correspondence of the frontmost and rearmost portions of the side retainer 4, consequently the interruptions are not visible in FIGS. 17-19. In an alternative embodiment (not shown), the insert 3 arranged in correspondence to the side retainer 4 can be only one.

[0136] The helmet 1 of fourth embodiment also comprises a top retainer 4 shown in FIG. 23. The top retainer 4 comprises a portion 22 that is substantially dome-shaped and some arms employed for connecting the top retainer 4 to the shell 2.

[0137] The dome-shaped portion 22 allows a simple and comfortable fit with any kind of head.

[0138] 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 FIGS. 17-19. Certain arms may not have an end comprising a slot 13, like the frontal one in FIG. 23.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] In a fifth embodiment, shown in FIGS. 25 and 26, the retainer 4 is one and is configured to trap one or more inserts 3.

[0144] As FIG. 25 shows, the retainer 4 is split in more parts connected to each other: two fixed parts 4C and one moveable part 4D. The fixed parts 4C of the retainer 4 are connectable to the shell 2 via said plugs 4A, as mentioned above and shown in FIG. 26, while the moveable part 4D of the retainer 4 is connected to the fixed part 4 through deformable means 24. This chain of connection of the retainer 4 to the shell 2 is reversible and deformable and allows a relative movement of the moveable part 4D of the retainer 4 with respect to its fixed part 4C in case of oblique impacts on the shell 2.

[0145] 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.

[0146] 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 FIG. 26. In this way, the moveable part 4D can move with respect to the shell 2 and the pins 14 move within the slots 13 until they hit the inner sides of the slots 13. Therefore, the moveable part 4D is not able to escape from the helmet 1, but only to perform small movements that are enough for dissipating the energy of an oblique impact received by the shell 2.

[0147] As shown in FIGS. 25 and 26, the deformable means 24 are elastic cushions arranged between the fixed part 4C and moveable part 4D. The deformable means 24 allow relative movements of the moveable part 4D with respect to the fixed parts 4C in any direction. In this manner, shear forces are absorbed independently from the direction of impact. The deformable means 24 are preferably sandwiched between the moveable part 4D and fixed part 4C of the retainer 4, as shown in FIGS. 25 and 26. Alternatively, the deformable means 24 are stretchable connections configured to elongate if the moveable part 4C gets away from the fixed part 4C. In a further alternative, the deformable means 24 are configured to plastically and irreversibly deform in order to absorb more energy and to avoid rebounding forces.

[0148] 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.

[0149] 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.

LEGEND OF REFERENCE SIGNS

[0150] 1 helmet [0151] 2 shell [0152] 3 insert [0153] 4 retainer [0154] 4A plug of retainer [0155] 4B shoulder of the retainer [0156] 4 side retainer [0157] 4 top retainer [0158] 4C fixed part of the retainer [0159] 4D moveable part of the retainer [0160] 5 vent [0161] 6 place [0162] 7 shoulder of the shell [0163] 8 low frictional layer [0164] 9 upper skin [0165] 10 lower skin [0166] 11 upper and outer surface of the shell [0167] 12 lower and outer surface of the shell [0168] 13 snap-pin [0169] 13 slot [0170] 14 snap-basket [0171] 14 pin [0172] 15L longitudinal rib of the shell [0173] 15R transverse rib of the shell [0174] 16 cell [0175] 17 inner surface of the shell [0176] 18 Velcro coin [0177] 19 recess [0178] 20 comfort liner [0179] 21 multi-purpose connector [0180] 22 dome-shaped portion [0181] 23 connecting elements [0182] 24 deformable means [0183] L longitudinal direction insert [0184] T transverse direction insert