Functional reactive layer helmet

Abstract

The present invention relates to a helmet ( 1 ) comprising: a first layer ( 10 ) forming an outer surface of the helmet ( 1 ), a second layer ( 30 ), and a reactive layer ( 20 ) sandwiched between the first layer ( 10 ) and the second layer ( 30 ), whereby said reactive layer ( 20 ) comprises a plurality of rigid balls ( 2 ) allowing the first layer ( 10 ) to roll upon the second layer ( 30 ) as soon as the helmet ( 1 ) undergoes an impact of an intensity greater than a predetermined threshold.

1 . A helmet ( 1 ) comprising:
 A first layer ( 10 ) forming an outer surface of the helmet ( 1 ),   a second layer ( 30 ), and   a reactive layer ( 20 ) sandwiched between the first layer ( 10 ) and the second layer ( 30 .   
     
     
         2 . The helmet according to  claim 1 , wherein the reactive layer comprises a plurality of rigid balls ( 2 ) that remain rigid during normal use of the helmet ( 1 ) and are configured to roll at an impact threshold over an outer surface ( 30   a ) of the second layer ( 30 ). 
     
     
         3 . The helmet according to  claim 2 , wherein the balls ( 2 ) are distributed along an inner surface ( 10   a ) of the first layer ( 10 ) such that they cover an area that corresponds to 10% to 50%, preferably 15% to 30%, preferably about 20% of the area of said inner surface ( 10   a ) of the first layer ( 10 ). 
     
     
         4 . The helmet according to  claim 2 or 3 , wherein the rigid balls ( 2 ) are bonded to a substrate film ( 21 ) via an adhesive ( 22 ) configured to undergo brittle failure. 
     
     
         5 . The helmet according to  claim 4 , wherein the substrate film ( 21 ) comprises a thickness smaller than 200 μm. 
     
     
         6 . The helmet according to  claim 4 or 5 , wherein the substrate film ( 21 ) comprises an adhesive layer ( 23 ) preferably consisting of a pressure sensitive adhesive arranged on a side of the substrate film ( 21 ) facing away from said plurality of balls ( 2 ). 
     
     
         7 . The helmet according to  claim 4  or according to one of the  claims 5 to 6  insofar referring to  claim 4 , wherein the reactive layer ( 20 ) is a membrane ( 20 ) bonded to the first and the second layer ( 10 ,  30 ), wherein the membrane ( 20 ) comprises said substrate film ( 21 ) and the plurality of balls ( 2 ) arranged thereon. 
     
     
         8 . The helmet according to  claims 6 and 7 , wherein the membrane ( 20 ) is bonded to an outer surface ( 30   a ) of the second layer ( 30 ) via said adhesive layer ( 23 ) of the substrate film ( 21 ). 
     
     
         9 . The helmet according to one of the  claims 7 to 8 , wherein the membrane ( 20 ) is bonded to an inner surface ( 10   a ) of the first layer ( 10 ) via an adhesive layer ( 14 ), preferably an adhesive layer ( 14 ) comprising a thermo-softening adhesive. 
     
     
         10 . The helmet according to  claim 9 , wherein the first layer ( 10 ) comprises a sheet ( 11 ), a color layer ( 12 ) arranged on an inner surface of the sheet ( 11 ), a protective layer ( 13 ) arranged on the color layer ( 12 ), wherein said adhesive layer ( 14 ) that bonds the membrane ( 20 ) to the inner surface of the first layer ( 10 ) is bonded to the protective layer ( 13 ). 
     
     
         11 . The helmet according to  claim 10 , wherein the protective layer ( 13 ) is a heat resistant ink layer. 
     
     
         12 . The helmet according to  claim 10 , wherein the protective layer ( 13 ) is a plastic layer. 
     
     
         13 . The helmet according to one of the  claims 10 to 12 , wherein the protective layer ( 13 ) comprises a thickness below 0.1 mm and/or a yield strength larger than 20 MPa. 
     
     
         14 . The helmet according to one of the  claims 10 to 13 , wherein the protective layer ( 13 ) has a thermal expansion differing less than 5% from a thermal expansion of a material of the first layer ( 10 ). 
     
     
         15 . The helmet according to one of the  claims 1 to 9 , wherein the first layer ( 10 ) that is a twin sheet assembly comprising an outer sheet ( 11 ) and an inner sheet ( 110 ). 
     
     
         16 . The helmet according to  claim 15 , wherein the inner sheet ( 110 ) of the twin sheet assembly ( 10 ) is perforated. 
     
     
         17 . The helmet according to  claim 15 or 16 , wherein a color layer ( 12 ) and an adhesive layer ( 140 ) are arranged between the outer and the inner sheet ( 11 ,  110 ), wherein particularly the color layer ( 12 ) is arranged on the outer sheet ( 11 ) and the inner sheet ( 110 ) is bonded to the outer sheet ( 11 ) via the adhesive ink layer ( 140 ). 
     
     
         18 . The helmet according to  one of the preceding claims , wherein the helmet ( 1 ) comprises an energy absorbing layer ( 40 ), wherein an inner surface ( 30   b ) of the second layer ( 30 ) is bonded to the energy absorbing layer ( 40 ) by an adhesive layer ( 33 ). 
     
     
         19 . The helmet according to  claim 18 , wherein the second layer ( 30 ) comprises recesses and/or through-holes through which portions of the energy absorbing layer ( 40 ) extends towards the first layer ( 10 ), said portions of the energy absorbing layer ( 40 ) being bonded to the first layer ( 10 ). 
     
     
         20 . The helmet according to  claim 19 , wherein an outer surface of the second layer ( 30 ) locally bends upwards around the respective recess and/or through-hold to reduce a separation between an inner surface of the first layer ( 10 ) and said outer surface of the second layer ( 30 ), particularly so as to avoid a bleeding of the energy absorbing layer ( 40 ) into a volume between said inner and outer surfaces during manufacturing of the energy absorbing layer ( 40 ). 
     
     
         21 . The helmet according to  one of the preceding claims , wherein the reactive layer ( 20 ) is configured to facilitate relative movement between the first layer ( 10 ) and the second layer ( 30 ) by the rolling of balls ( 2 ) of said plurality of balls ( 2 ) between the first and the second layer ( 10 ,  30 ), wherein said rolling of balls ( 2 ) provides a low rolling resistance in the range from 0.0001 to 0.2, particularly 0.03 to 0.05, particularly 0.025 to 0.04, between the balls ( 2 ) and an inner surface ( 10   a ) of the first layer ( 10 ) or connected to the first layer ( 10 ) or between the balls ( 2 ) and an outer surface ( 30   a ) of the second layer ( 30 ) or connected to the second layer ( 30 ). 
     
     
         22 . The helmet according to  one of the preceding claims , wherein the inner surface ( 10   a ) of the first layer ( 10 ) and the outer surface ( 30   a ) of the second layer ( 30 ) are concentric with respect to one another. 
     
     
         23 . The helmet according to  one of the preceding claims , wherein the membrane ( 20 ) or reactive layer ( 20 ) is congruent to an inner surface of the first layer ( 10 ). 
     
     
         24 . The helmet according to  one of the preceding claims , wherein the second layer ( 30 ) forms at least one ramp to cause the first layer ( 10 ) to bend away from the second layer ( 30 ) to avoid butting up of the first layer ( 10 ) on a portion of the second portion. 
     
     
         25 . The helmet according to  one of the preceding claims , wherein the energy absorbing layer ( 40 ) and/or the second layer ( 30 ) comprises an edge portion ( 80 ) having a chamfered or rounded edge ( 80   a ) to prevent a trailing edge ( 10   g ) of the first layer ( 10 ) from becoming caught on said edge portion ( 80 ) when moving relative to the second layer ( 30 ) and/or energy absorbing layer ( 40 ) over said edge portion ( 80 ) 
     
     
         26 . The helmet according to  one of the preceding claims , wherein the reactive layer ( 20 ) is configured to hold the first layer ( 10 ) such that a tangential force required to activate rolling of balls ( 2 ) of the reactive layer is about 0.1 kN, or such that an energy introduced by the impact force (F T ) has to exceed 2.5 J to activate rolling of the balls ( 2 ). 
     
     
         27 . The helmet according to  one of the preceding claims , wherein an outer surface ( 30   a ) of the second layer ( 30 ) comprises a plurality of protrusions that provide resistance to the rolling of balls ( 2 ) of said plurality of balls ( 2 ). 
     
     
         28 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) comprises a front portion ( 101 ) connected to the energy absorbing layer ( 40 ) causing the front portion ( 101 ) of the first layer ( 10 ) to remain in place during an oblique impact in a first direction (D 1 ) from a rear of the helmet ( 1 ) towards the front of the helmet ( 1 ), while a remaining portion ( 102 ) of the first layer ( 10 ) being connected to the front portion ( 101 ) is separated from the second layer ( 30 ), and wherein, during an oblique impact in a second direction (D 2 ) from the front of the helmet ( 1 ) towards the rear from the helmet ( 1 ), the front portion ( 101 ) is configured to disengage from the energy absorbing layer ( 40 ) or the remaining portion of the first layer ( 10 ) is configured to tear apart from the front portion of the first layer ( 10 ). 
     
     
         29 . The helmet according to  claim 28 , wherein said front portion ( 101 ) forms a tab comprising an opening ( 103 ), the tab being embedded in the energy absorbing layer ( 40 ), wherein a portion ( 400 ) of the energy absorbing layer ( 40 ) extends through said opening ( 103 ) such that said portion ( 400 ) holds the tab in place upon said oblique impact in the first direction (D 1 ) and preferably breaks to release the tab upon said oblique impact in the second direction (D 2 ). 
     
     
         30 . The helmet according to  one of the preceding claims , wherein upon an impact force on the first layer ( 10 ), the first layer ( 10 ) is configured to deform in shape and move relative to the second layer ( 30 ). 
     
     
         31 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) comprises an edge region ( 10   b ), wherein the edge region ( 10   b ) is configured to inhibit a transfer of a radial force (F R ) from the first layer ( 10 ) to the second layer ( 30 ). 
     
     
         32 . The helmet according to  claim 31 , wherein said edge region ( 10   b ) is formed by a portion of the first layer ( 10 ) extending at an angle (x) with respect to a normal of an outer surface of the second layer ( 30 ), said angle (x) being in the range from 20° to 80°, preferably 30° to 70°, preferably 40° to 60°, preferably 40° to 50°. 
     
     
         33 . The helmet according to one of the  claims 1 to 30 , wherein the first layer ( 10 ) comprises an edge region ( 10   b ) that is connected to an outer surface ( 30   a ) of the second layer ( 30 ) by a compressible intermediary layer ( 4 ), particularly to inhibit a transfer of a radial force (F R ) from the first layer ( 10 ) to the second stiff layer 
     
     
         34 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) is configured to store and release energy as a result of an impact to the first layer ( 10 ) to reduce rotational motion of a head of a person wearing the helmet ( 1 ). 
     
     
         35 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) is configured to change its shape relative to the second layer ( 30 ) during impact, wherein particularly the first layer ( 10 ) comprises an auxetic structure. 
     
     
         36 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) is shaped to pivot the helmet ( 1 ) during impact and thereby reduce rotational motion of a head of a person wearing the helmet ( 1 ). 
     
     
         37 . The helmet according to wherein the first layer ( 10 ) is configured to deform during an impact such that a free movement of the first layer ( 10 ) is inhibited during impact, wherein particularly said deformation causes a peeling of an adhesive ( 22 ) bonding the balls ( 2 ) to the outer surface ( 30   a ) of the second layer ( 30 ). 
     
     
         38 . The helmet according to  claim 36 , wherein the first layer ( 10 ) comprises a buckling ( 5 ) for supporting said pivoting. 
     
     
         39 . The helmet according to  claim 2  and according to  claim 37 , wherein upon an impact, the buckling ( 5 ) is configured to flatten and increase in width resulting in a translational movement of a boundary region ( 50 ) of the buckling causing the balls ( 2 ) to roll. 
     
     
         40 . The helmet according to  claim 38 , wherein the buckling ( 5 ) is configured to provide a redirection of a normal force of an impact acting on the first layer ( 10 ) such that the normal force comprises a distance (A) to the center of mass (C) of the system comprised of the helmet ( 1 ) and a head of a person wearing the helmet ( 1 ). 
     
     
         41 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ), particularly the buckling ( 5 ), is configured to deform on impact to prevent geometric locking of the first layer ( 10 ) due to a mechanical interaction with an adjacent structure of the helmet ( 1 ), wherein particularly deformation of the first layer ( 10 ), particularly of the buckling ( 5 ), causes an edge region ( 51 ) of the first layer ( 10 ) to lift up from the reactive layer ( 20 ) so as to not become entangled with adjacent structures of the helmet ( 1 ). 
     
     
         42 . The helmet according to  one of the preceding claims , wherein an inner surface ( 10   a ) of the first layer ( 10 ) is configured to become congruent with an outer surface ( 30   a ) of the second layer ( 30 ) during an impact, particularly so as to increase the duration of impact and sliding before contact. 
     
     
         43 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) contacts the reactive layer ( 20 ) merely via one or several restricted portions of an inner surface ( 10   a ) of the first layer ( 10 ), wherein particularly said portion(s) is/are arranged at a perimeter of the first layer ( 10 ). 
     
     
         44 . The helmet according to  claim 43 , wherein said portion(s) comprise an increased stiffness compared to an adjacent portion of the first layer ( 10 ), particularly so as to reduce the area of the reactive layer necessary for facilitating relative movement between the first layer ( 10 ) and the second layer ( 30 ). 
     
     
         45 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) is an injection-moulded first layer ( 10 ) and/or wherein the second layer ( 30 ) is an injection-moulded second layer ( 30 ). 
     
     
         46 . The helmet according to  one of the preceding claims , wherein a portion of an inner surface of the first layer ( 10 ) is bonded to a portion of an outer surface of the second layer ( 30 ). 
     
     
         47 . The helmet according to  one of the preceding claims , wherein the first layer ( 10 ) is connected to the second layer ( 30 ) by connectors ( 6 ), the respective connector ( 6 ) protruding from an inner surface ( 10   a ) of the first layer ( 10 ) and extending through an associated through-opening ( 300 ) of the second layer ( 30 ) with an end portion ( 60 ) of the connector ( 6 ), the end portion ( 60 ) engaging with the second layer ( 30 ) to connect the first layer ( 10 ) to the second layer ( 30 ), wherein the respective connector ( 6 ) is configured to break at said impact threshold to release the first layer ( 10 ) from the second layer ( 30 ). 
     
     
         48 . The helmet according to  one of the preceding claims , wherein the first layer is a sacrificial layer configured to smooth out a surface impacting on the helmet to allow the balls to roll on it, wherein the sacrificial layer is configured to be completely or partially released from the helmet during an oblique impact and particularly configured to not translate during said impact relative to the impacting surface. 
     
     
         49 . The helmet according to  one of the preceding claims , wherein an energy necessary to release each ball is in the range between 0.005 Joules and 0.5 Joule per ball. 
     
     
         50 . The helmet comprises a plurality of first layers ( 10 ), and a reactive layer ( 20 ) sandwiched between each first layer ( 10 ) and the second layer ( 30 ). 
     
     
         51 . A method for manufacturing a helmet, particularly a helmet ( 1 ) for cycling, particularly a helmet ( 1 ) according to  one of the preceding claims , wherein the method comprises the steps of:
 (a) Providing a first layer ( 10 ) and an adhesive layer ( 14 ) arranged thereon,   (b) Providing a second layer ( 30 ) and an adhesive layer ( 33 ) arranged thereon,   (c) Providing a membrane ( 20 ) comprising a plurality of balls bonded to a substrate film ( 21 ) of the membrane ( 20 ) using an adhesive ( 22 ), the substrate film ( 21 ) comprising an adhesive layer ( 23 ) on a side facing away from said plurality to balls,   (d) Arranging the membrane ( 20 ) on an outer side ( 30   a ) of the second layer ( 30 ) and bonding the membrane ( 20 ) to the second layer ( 30 ) via said adhesive layer ( 23 ) of the substrate film ( 21 ),   (e) Arranging the first layer ( 10 ), the second layer ( 30 ) and the membrane ( 20 ) in a cavity of a mould, wherein the membrane ( 20 ) is arranged between the first and the second layer ( 10 ,  30 ), and   (f) Providing a material in the cavity adjacent the adhesive layer ( 33 ) arranged on the second layer ( 30 ) for forming an energy absorbing layer ( 40 ) of the helmet ( 1 ), wherein the energy absorbing layer ( 40 ) is bonded to an inner surface ( 30   b ) of the second layer ( 30 ) via said adhesive layer ( 33 ) arranged on the second layer ( 30 ), and bonding the plurality of balls ( 2 ) to the first layer ( 10 ) via said adhesive layer ( 14 ) arranged on the first layer ( 10 ).   
     
     
         52 . The method according to  claim 51 , wherein the adhesive layer ( 14 ) arranged on the first layer ( 10 ) is a thermo-softening adhesive layer ( 14 ), and/or wherein the adhesive layer ( 33 ) arranged on the second layer ( 30 ) is a thermo-softening adhesive layer ( 33 ), and/or wherein the adhesive layer ( 23 ) of the substrate film comprise a pressure sensitive adhesive. 
     
     
         53 . The method according to  claim 51 or 52 , wherein providing a first layer ( 10 ) in step (a) comprises proving a sheet ( 11 ), applying a color layer ( 12 ) on the sheet ( 11 ), wherein thereafter preferably a light bleed preventing base coat is applied on the color layer  12 , applying a protective layer ( 13 ) on the color layer ( 12 ), and wherein arranging said adhesive layer ( 14 ) on the first layer ( 10 ) comprises arranging said adhesive layer ( 14 ) on the protective layer ( 13 ). 
     
     
         54 . The method according to one of the  claims 51 to 53 , wherein providing the second layer ( 30 ) in step (b) comprises proving a sheet ( 31 ), applying a color layer ( 32 ) on the sheet ( 31 ) of the second layer ( 30 ), wherein thereafter preferably a light bleed preventing base coat is applied on the color layer  32 , and wherein arranging said adhesive layer ( 33 ) on the second layer ( 30 ) comprises arranging said adhesive layer ( 33 ) on the color layer ( 32 ) of the second layer ( 30 ). 
     
     
         55 . The method according to one of the  claims 51 to 54 , wherein the step (c) of providing the membrane ( 20 ) comprises providing the substrate film ( 21 ) by kiss cutting a laminate ( 7 ) comprising a top layer ( 70 ) and a backing ( 71 ), the substrate film ( 21 ) being kiss cut from the top layer ( 70 ) resulting in the substrate film ( 21 ) arranged on the backing ( 71 ) and in a surrounding portion ( 72 ) of the top layer ( 70 ), wherein particularly the substrate film ( 21 ) comprises an elongated shape being adapted to a geometry of a corresponding portion of the outer surface ( 30   a ) of the second layer ( 30 ). 
     
     
         56 . The method according to  claim 55 , wherein step (c) further comprises:
 removing said surrounding portion ( 72 ),   arranging dots of said adhesive ( 22 ) onto the substrate film ( 21 ), and   placing a ball ( 2 ) of said plurality of balls on each dot of adhesive ( 22 ) to bond the balls ( 2 ) to the substrate film ( 21 ).   
     
     
         57 . The method according to  claim 55 , wherein step (c) further comprises:
 applying a layer of said adhesive ( 22 ) onto the substrate film ( 21 ),   removing said surrounding portion ( 72 ), and   placing said plurality of balls ( 2 ) on the layer of said adhesive ( 22 ) to bond the balls ( 2 ) to the substrate film ( 21 ).   
     
     
         58 . The method according to one of the  claims 51 to 57 , wherein the second layer ( 30 ) comprises recesses and/or through-holes through which the material is made to extend towards the first layer ( 10 ) to bond with the first layer ( 10 ). 
     
     
         59 . A helmet (B 100 ) for protecting the head of a person upon an impact, the helmet (B 100 ) comprising an outer surface, the helmet (B 100 ) being configured to reduce negative rotation of a head of the person wearing the helmet (B 100 ) resulting from an impact force acting on the outer surface of the helmet (B 100 ) upon said impact. 
     
     
         60 . The helmet (B 100 ) according to  claim 59 , wherein said negative rotation results from a negative torque (B 2 ) corresponding to the cross product of the normal component (F N ) of the impact force, which normal component extends perpendicular to the outer surface, and a first lever arm vector (L 1 ) between the center of mass (B 90 ) of an assembly formed by said head and helmet (B 100 ) and the normal component (F N ). 
     
     
         61 . The helmet ( 100 ) according to  claim 59 or 60 , wherein for reducing said negative rotation the helmet (B 100 ) comprises at least one motion inhibiting element (B 70 ). 
     
     
         62 . The helmet (B 100 ) according to one of the  claims 59 to 61 , wherein the helmet (B 100 ) comprises at least one outer protective layer (B 12 ) forming said outer surface and an inner layer (B 11 ), wherein for reducing a positive rotation of the head of the person upon said impact, the at least one outer protective layer (B 12 ) is configured to move relative to the inner layer (B 11 ). 
     
     
         63 . The helmet (B 100 ) according to  claim 62 , wherein said positive rotation is opposite the negative rotation and results from a positive torque ( 1 ) corresponding to the cross product of a tangential friction force (F T ) acting on the outer surface of the helmet (B 100 ) upon said impact and a second lever arm vector (L 2 ) extending parallel to said normal component (F N ) to the center of mass (B 90 ). 
     
     
         64 . The helmet (B 100 ) according to one of the  claims 60 to 63 , wherein the at least one motion inhibiting element (B 70 ) is adapted such that the negative torque (B 2 ) counteracts the positivetorque ( 1 ) leading to an angular rotation velocity of the helmet (B 100 ) and head upon said impact in the range from −15 rad/s to +15 rad/s, preferably −10 rad/s to +10 rad/s, more preferably −5 rad/s to +5 rad/s. 
     
     
         65 . The helmet (B 100 ) according to one of the  claims 59 to 64 , wherein the at least one motion inhibiting element (B 70 ) is arranged between the inner layer (B 11 ) and the at least one outer protective layer (B 12 ). 
     
     
         66 . The helmet (B 100 ) according to one of the  claims 61 to 65 , wherein the motion inhibiting element (B 70 ) comprises or is a motion inhibiting layer (B 13 ). 
     
     
         67 . The helmet (B 100 ) according to  claim 66 , wherein the motion inhibiting layer (B 13 ) is integrally formed with the inner layer (B 11 ) and/or the at least one outer protective layer (B 12 ). 
     
     
         68 . The helmet (B 100 ) according to  claim 66 or 67 , wherein the motion inhibiting layer (B 13 ) is configured to deform upon the impact force. 
     
     
         69 . The helmet (B 100 ) according to one of the  claims 62 to 6 , further comprising an intermediate layer (B 14 ) arranged between the inner layer (B 11 ) and the at least one outer protective layer (B 12 ), said intermediate layer (B 14 ) being configured to promote the relative motion between the inner layer (B 11 ) and the at least one outer protective layer (B 12 ). 
     
     
         70 . The helmet (B 100 ) according to one of the  claims 66 to 69 , wherein the motion inhibiting layer (B 13 ) comprises a flexible layer (B 15 ), particularly a fabric or a webbing arranged between the motion inhibiting layer ( 13 ) and at least one of the following: the inner layer (B 11 ), the intermediate layer (B 14 ), the at least one outer protective layer (B 12 ). 
     
     
         71 . The helmet (B 100 ) according to  claim 70 , wherein the flexible layer (B 15 ) is configured to counteract the motion of the intermediate layer (B 14 ) upon the impact. 
     
     
         72 . The helmet (B 100 ) according to one of the  claims 62 to 71 , wherein at least one of the following comprises a plurality of stacked sub-layers: the inner layer (B 11 ), the at least one outer protective layer (B 12 ), the motion inhibiting layer (B 13 ), the intermediate layer (B 14 ). 
     
     
         73 . The helmet (B 100 ) according to one of the  claims 66 to 72 , wherein the motion inhibiting layer (B 13 ) is arranged at least partially within the intermediate layer (B 14 ). 
     
     
         74 . The helmet ( 100 ) according to one of the  claims 69 to 73 , wherein the intermediate layer ( 14 ) is integrally formed with at least one of the following: the inner layer (B 11 ), the motion inhibiting layer (B 13 ), the at least one outer protective layer (B 12 ). 
     
     
         75 . The helmet ( 100 ) according to one of the  claims 69 to 74 , wherein the intermediate layer ( 14 ) and/or the motion inhibiting layer ( 13 ) comprises rollable elements (B 20 ), said rollable elements (B 20 ) being configured to promote the motion of the inner layer (B 11 ) relative to the at least one outer protecting layer (B 12 ) upon the impact. 
     
     
         76 . The helmet ( 100 ) according to  claim 75 , wherein the intermediate layer ( 14 ) and/or the motion inhibiting layer (B 13 ) comprises breaking elements configured to fail upon the impact, enabling the rollable elements (B 20 ) to interact with the inner layer (B 11 ) and the at least one outer protective layer (B 12 ), so as to promote the motion of the inner layer (B 11 ) relative to the at least one outer protecting layer (B 12 ). 
     
     
         77 . The helmet ( 100 ) according to  claim 75 or 76 , wherein together with the inner layer (B 11 ) and the at least one outer protective layer (B 12 ), the motion inhibiting layer (B 13 ) defines at least one volume (B 50 ), so as to confine at least a fraction of the rollable elements (B 20 ) in the at least one volume (B 50 ). 
     
     
         78 . The helmet (B 100 ) according to one of the  claims 75 to 77 , wherein an elasticity of the rollable elements (B 20 ) is lower or larger than an elasticity of at least one of the following:
 the inner layer (B 11 ), the intermediate layer (B 14 ), the at least one outer protective layer (B 12 ), the motion inhibiting layer (B 13 ).   
     
     
         79 . The helmet (B 100 ) according to  claim 78 , wherein the lower elasticity corresponds to a young's modulus of less than 3 GPa. 
     
     
         80 . The helmet (B 100 ) according to one of the  claims 69 to 79 , wherein a rolling resistance coefficient between the intermediate layer (B 14 ) and the at least one outer protective layer (B 12 ) and/or the inner layer (B 11 ) is below 0.2. 
     
     
         81 . The helmet ( 100 ) according to one of the  claims 66 to 80 , wherein a coefficient of friction between the motion inhibiting layer (B 13 ) and the intermediate layer (B 14 ) or the at least one outer protective layer (B 12 ) or the inner layer (B 11 ) differs from a coefficient of friction between the intermediate layer (B 14 ) and the at least one outer protective layer (B 12 ) or the inner layer (B 11 ). 
     
     
         82 . The helmet ( 100 ) according to one of the  claims 66 to 81 , wherein a coefficient of friction between the intermediate layer (B 14 ) or the motion inhibiting layer (B 13 ) and the at least one outer protective layer (B 12 ) or the inner layer (B 11 ) is below 0.8. 
     
     
         83 . The helmet (B 100 ) according to one of the  claims 66 to 82 , wherein the motion inhibiting layer (B 13 ) comprises a viscous fluid or gel (B 60 ). 
     
     
         84 . The helmet (B 100 ) according to  claim 83 , wherein the viscous fluid or gel (B 60 ) comprises a viscosity within 0.001 Pa s and 10 Pa s. 
     
     
         85 . The helmet (B 100 ) according to one of the  claims 66 to 82 , wherein the motion inhibiting layer comprises a non-Newtonian fluid or gel (B 61 ). 
     
     
         86 . The helmet (B 100 ) according to one of the  claims 59 to 85 , wherein individual motion inhibiting elements (B 70 ) forming the motion inhibiting elements (B 70 ) are configured to rupture upon a predetermined rupture force caused by the impact, and wherein a geometrical feature, particularly a diameter, a width or a length of an individual inhibiting element (B 70 ) is indicative for an individual rupture force required to rupture an individual inhibiting element (B 70 ), said rupture force counteracting the negative rotation of the helmet (B 100 ) upon the impact. 
     
     
         87 . The helmet (B 100 ) according to one of the  claims 62 to 86 , wherein the motion inhibiting elements (B 70 ) cover less than 80% of a total lateral surface area defined by the at least one outer protective layer (B 12 ). 
     
     
         88 . The helmet (B 100 ) according to one of the  claims 59 to 87 , wherein the motion inhibiting elements (B 70 ) are formed as at least one of the following: a cylinder, a cone, a pyramid, a cuboid, a truncated cone. 
     
     
         89 . The helmet (B 100 ) according to one of the  claims 62 to 88 , wherein the motion inhibiting elements (B 70 ) contact the at least one outer protective layer (B 12 ) and the inner layer (B 11 ) via a lateral contact surface area, wherein a ratio of the lateral contact surface area and the total lateral surface area is within 0.05 and 0.5. 
     
     
         90 . The helmet (B 100 ) according to one of the  claims 66 to 89 , wherein the motion inhibiting layer (B 13 ) comprises a connector (B 80 ) being integrally formed with at least two of the following: the inner layer (B 11 ), the intermediate layer (B 14 ), the at least one outer protective layer (B 12 ). 
     
     
         91 . The helmet (B 100 ) according to  claim 90 , said connector (B 80 ) being configured to deform and/or to rupture upon the impact. 
     
     
         92 . The helmet according to  claim 91 , wherein the motion inhibiting layer (B 13 ) comprises a plurality of connectors (B 80 ), said connectors (B 80 ) being configured to deform and/or rupture simultaneously and/or sequentially upon the impact. 
     
     
         93 . The helmet (B 100 ) according to  claim 92 , wherein individual connectors (B 80 ) forming the plurality of connectors (B 80 ) comprise individual rupture forces, said individual rupture forces taking on at least two values and wherein the rupture forces counteract the negative rotation of the helmet (B 100 ) upon the impact. 
     
     
         94 . The helmet (B 100 ) according to one of the  claims 90 to 93 , wherein the connector (B 80 ) comprises or is an adhesive. 
     
     
         95 . The helmet (B 100 ) according to one of the  claims 90 to 94 , wherein the connector (B 80 ) has a different elasticity or stiffness than the inner layer (B 11 ) and/or the at least one outer protective layer (B 12 ). 
     
     
         96 . The helmet (B 100 ) according to one of the  claims 90 to 95 , wherein the connector (B 80 ) comprises at least one of the following: a thermoplastic, an elastomer, a ceramic or a metal. 
     
     
         97 . The helmet (B 100 ) according to one of the  claims 59 to 96 , wherein the motion inhibiting layer (B 13 ) comprises at least one of the following: a plastic material, an elastic material, a polymer, a metal. 
     
     
         98 . The helmet (B 100 ) according to one of the  claims 66 to 97 , wherein the motion inhibiting layer (B 13 ) is configured such that the reduction of negative rotation of the helmet (B 100 ) depends on a direction of the impact, particularly a direction of the tangential friction force (F T ). 
     
     
         99 . The helmet (B 100 ) according to  claim 98 , wherein the motion inhibiting layer (B 13 ) is configured such that the reduction of negative rotation upon an impact resulting in a rotation of the helmet (B 100 ) around a first axis is larger than the reduction of negative rotation upon an impact resulting in a rotation of the helmet ( 100 ) around a second axis. 
     
     
         100 . The helmet (B 100 ) according to  claim 99 , wherein the first axis extends through a coronal plane within a head of a person wearing the helmet (B 100 ) and wherein the second axis extends through a sagittal plane within the head of the person wearing the helmet (B 100 ). 
     
     
         101 . The helmet ( 100 ) according to one of the  claims 62 to 100 , wherein at least two of the following are configured to geometrically and/or mechanically lock so as to reduce the negative rotation upon impact: the inner layer (B 11 ), the intermediate layer (B 14 ), the motion inhibiting layer (B 13 ), the outer protective layer (B 12 ). 
     
     
         102 . The helmet (B 100 ) according to one of the  claims 61 to 101 , wherein in the absence of the motion inhibiting elements (B 70 ) or the motion inhibiting layer (B 13 ), upon impact, the helmet (B 100 ) would experience negative rotation, or exceed a pre-defined positive threshold of positive rotation. 
     
     
         103 . The helmet ( 1 , B 100 ) according to  one of the preceding claims , wherein the rigid balls ( 2 ) are separated from one another, particularly so as to reduce contact between balls ( 2 ) upon rolling of the balls ( 2 ). 
     
     
         104 . The helmet ( 1 ) according to one of the  claims 1 to 58 , wherein the rigid balls ( 2 ) are spaced apart from one another, particularly so as to reduce contact between balls ( 2 ) upon rolling of the balls ( 2 ). 
     
     
         105 . The helmet ( 1 ) according to one of the  claims 1 to 58 , wherein the substrate film ( 21 ) has applied thereto an ink coloring dye and/or is stiff so as to prevent movement of the balls ( 2 ) during processing. 
     
     
         106 . The helmet ( 1 ) according to one of the  claims 1 to 58 , wherein the first layer ( 10 ) is configured to flex during an impact.