Impact absorbing structures for athletic helmet
A helmet includes an outer shell, an impact absorbing layer positioned inside the outer shell, and a foam layer interior to the impact absorbing layer. The impact absorbing layer includes a plurality of impact absorbing structures positioned inside the outer shell, wherein at least a portion of the outer shell is flexible to transmit an impact force to a localized section of the plurality of impact absorbing structures. One or more of the plurality of impact absorbing structures include a plurality of filaments, wherein ends of at least some of the filaments are joined at a node and the at least some of the filaments are capable of buckling and absorbing energy when subjected to the impact force.
1 . A helmet comprising:
an outer shell; and
an impact absorbing layer comprising a plurality of impact absorbing structures of polyurethane material positioned inside the outer shell, wherein at least a portion of the outer shell is flexible to transmit an impact force to a localized section of the plurality of impact absorbing structures positioned inside the outer shell, wherein one or more of the plurality of impact absorbing structures comprise a plurality of filaments including at least three intersecting filaments connected at an intermediate point between a respective first end of each filament of the at least three intersecting filaments and a respective second end of each filament of the at least three intersecting filaments, the intermediate point comprising a node between an inner surface of the outer shell and an outer surface of a wearer's head, wherein:
at least two of the at least three intersecting filaments are oblique to the inner surface of the outer shell;
the respective first end of each filament of the at least two of the at least three intersecting filaments is proximate the inner surface of the outer shell; and
the at least two of the intersecting filaments are capable of buckling and absorbing energy when subjected to the impact force.
2 . The helmet of claim 1 , wherein the one or more of the plurality of impact absorbing structures rebound to an undeformed shape once the impact force is removed.
3 . The helmet of claim 1 , further comprising a foam layer interior to the impact absorbing layer, wherein the foam layer comprises a foam pad.
4 . The helmet of claim 1 , wherein the impact absorbing layer is positioned proximate to the inner surface of the outer shell.
5 . The helmet of claim 1 , wherein an attachment angle between the at least two of the intersecting filaments at the intermediate point is less than 90 degrees.
6 . The helmet of claim 1 , wherein:
longitudinal axes of the at least two of the intersecting filaments are oblique to the inner surface of the outer shell at the respective end proximate the inner surface of the outer shell; and
an attachment angle between the longitudinal axes of the at least two of the intersecting filaments at the intermediate point is less than 90 degrees.
7 . The helmet of claim 1 , wherein the at least three intersecting filaments connect the intermediate point to faces of an enclosing polyhedron.
8 . The helmet of claim 1 , further comprising a face sheet proximate the respective ends of the at least two of the intersecting filaments.
9 . The helmet of claim 8 , wherein the face sheet joins the respective ends of the at least two of the intersecting filaments.
10 . The helmet of claim 9 , wherein the face sheet and the plurality of filaments comprise the same material.
11 . The helmet of claim 8 , wherein:
longitudinal axes of the at least two of the intersecting filaments are oblique to the inner surface of the outer shell at the respective end proximate the inner surface of the outer shell; and
an attachment angle between the longitudinal axes of the at least two of the intersecting filaments at the intermediate point is less than 90 degrees.
12 . The helmet of claim 11 , further comprising a second face sheet proximate opposing ends of the at least two of the intersecting filaments, wherein:
the second face sheet joins the opposing ends of the at least two of the intersecting filaments; and
the second face sheet and the plurality of filaments comprise the same material.
13 . The helmet of claim 1 , further comprising a face sheet proximate opposing ends of the at least two of the intersecting filaments proximate the outer surface of the wearer's head, wherein the face sheet joins the opposing ends of the at least two of the intersecting filaments and the face sheet and the plurality of filaments comprise the same material.
14 . The helmet of claim 13 , further comprising a foam layer interior to the impact absorbing layer, wherein the foam layer is disposed between the face sheet and a wearer.
15 . The helmet of claim 14 , wherein the one or more of the plurality of impact absorbing structures are mechanically secured to the inner surface of the outer shell by a press fit.
16 . A helmet comprising:
an outer shell; and
an impact absorbing layer comprising a plurality of impact absorbing structures of polyurethane material positioned inside the outer shell, wherein at least a portion of the outer shell is flexible to transmit an impact force to a localized section of the plurality of impact absorbing structures positioned inside the outer shell, wherein one or more of the plurality of impact absorbing structures comprise a plurality of filaments including a first filament, a second filament, and a third filament connected at an intermediate point between a respective first end of each filament of the first filament, the second filament and the third filament and a respective second end of each filament of the first filament, the second filament and the third filament, the intermediate point comprising a node between an inner surface of the outer shell and an outer surface of a wearer's head, wherein:
at least two of the first filament, the second filament and the third filament are oblique to the inner surface of the outer shell;
the respective first end of each filament of the at least two of the first filament, the second filament and the third filament is proximate the inner surface of the outer shell and the at least two of the first filament, the second filament and the third filament are capable of buckling and absorbing energy when subjected to the impact force;
the first filament, the second filament and the third filament are joined at an angle between 30 degrees and 120 degrees; and
the one or more of the plurality of impact absorbing structures rebound to an undeformed shape once the impact force is removed.
17 . The helmet of claim 16 , further comprising a foam layer interior to the impact absorbing layer, wherein the foam layer comprises a foam pad.
18 . The helmet of claim 16 , wherein the impact absorbing layer is positioned proximate to the inner surface of the outer shell.
19 . The helmet of claim 18 , wherein the impact absorbing layer is mechanically secured to the inner surface of the outer shell.
20 . The helmet of claim 19 , wherein the one or more of the plurality of impact absorbing structures is mechanically secured to the inner surface of the outer shell by a press fit.
21 . A helmet comprising:
an outer shell having a curved interior surface; and
an impact absorbing layer including a plurality of modular impact absorbing arrays positioned inside the outer shell, wherein at least a portion of the outer shell is flexible to transmit an impact force to a localized section of the impact absorbing layer positioned inside the outer shell, wherein each modular impact absorbing array of the plurality of modular impact absorbing arrays includes a concentric outer surface proximate the curved interior surface, a concentric inner surface, and an impact absorbing structure between the concentric outer surface and the concentric inner surface of the respective modular impact absorbing array, the impact absorbing structure comprising at least three intersecting structures of polyurethane material, wherein:
the at least three intersecting structures include a first structure, a second structure and a third structure;
the first structure, the second structure and the third structure each have a respective first end proximate the concentric outer surface and a respective second end proximate the concentric inner surface;
the first structure, the second structure and the third structure are connected at an intermediate point between the respective first end of each structure of the first structure, the second structure and the third structure and the respective second end of each structure of the first structure, the second structure and the third structure, the intermediate point comprising a node between the curved interior surface of the outer shell and an outer surface of a wearer's head; and
at least two of the first structure, the second structure and the third structure are oblique to the curved interior surface of the outer shell.
22 . The helmet of claim 21 , further comprising a foam layer interior to the impact absorbing layer, wherein:
the respective first end of each structure of the at least two of the first structure, the second structure and the third structure is secured to the concentric outer surface as a result of integral formation; and
the respective second end of each structure of the at least two of the first structure, the second structure and the third structure is secured to the concentric inner surface as a result of integral formation.