Cycling helmet with rotational impact attenuation
A helmet having an outer liner and an inner liner is disclosed. The inner liner is positioned at least partially inside the outer liner. The helmet includes at least one chin strap anchored to the outer liner and passing through an opening in the inner liner. The helmet further includes a plurality of return springs, each having a first end coupled to the outer liner, and a second end distal to the first end and coupled to the inner liner. The return springs bias the inner liner to a first position with respect to the outer liner. The inner liner is slidably coupled to the outer liner through the plurality of return springs and slidably movable relative to the outer liner between the first position and a second position where the inner liner and outer liner are rotated away from the first position.
1. A helmet, comprising:
an outer liner formed of a first foamed energy management material and comprising an inward-facing surface;
an inner liner formed of a second foamed energy management material and positioned at least partially inside the outer liner, the inner liner comprising an outward-facing surface facing the inward-facing surface of the outer liner;
at least one chin strap anchored to the outer liner and passing through an opening in the inner liner;
a plurality of return springs each comprising an elastomeric material, each return spring having a first end coupled to the inward-facing surface of the outer liner, a second end distal to the first end and coupled to the outward-facing surface of the inner liner, and a body connecting the first end and the second end, the plurality of return springs biasing the inner liner to a first position with respect to the outer liner; and
at least one leash coupling, each leash coupling comprising an upper end coupled to the outer liner, a lower end distal to the upper end and coupled to the inner liner, and a flexible tether that connects the upper end and the lower end, and passes through the inward-facing surface of the outer liner and the outward-facing surface of the inner liner;
wherein the inner liner is slidably coupled to the inward-facing surface of the outer liner through the plurality of return springs and slidably movable relative to the outer liner between the first position and a second position where the inner liner and outer liner are rotated with respect to each other away from the first position;
wherein both the inward-facing surface of the outer liner and the outward-facing surface of the inner liner are substantially parallel to a portion of a sphere;
wherein the body of each of the plurality of return springs is substantially tangential to the sphere; and
wherein, for each of the at least one leash coupling, a majority of the tether is located in a cavity formed in at least one of the outer liner and inner liner.
2. The helmet of claim 1 , further comprising at least one glide pad having an adhesive surface affixed to one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner, and a glide surface opposite the adhesive surface, the glide surface having a coefficient of friction lower than the coefficient of friction of the one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner.
3. The helmet of claim 1 , wherein at least one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner comprises an annealed surface.
4. The helmet of claim 1 , wherein the first foamed energy management material and the second foamed energy management material each comprise one of expanded polystyrene and expanded polypropylene.
5. A helmet, comprising:
an outer liner comprising an inward-facing surface;
an inner liner positioned at least partially inside the outer liner, the inner liner comprising an outward-facing surface facing the inward-facing surface of the outer liner;
a plurality of return springs comprising an elastomeric material, each return spring having a first end coupled to the inward-facing surface of the outer liner, a second end distal to the first end and coupled to the outward-facing surface of the inner liner, and a body connecting the first end and the second end, the plurality of return springs biasing the inner liner to a first position with respect to the outer liner; and
at least one chin strap anchored to the outer liner and passing through an opening in the inner liner;
wherein the inner liner is slidably coupled to the inward-facing surface of the outer liner through the plurality of return springs and slidably movable relative to the outer liner between the first position and a second position where the inner liner and outer liner are rotated with respect to each other away from the first position; and
wherein the body of each return spring of the plurality of return springs is substantially tangential to at least one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner.
6. The helmet of claim 5 , wherein the outer liner is formed of a first foamed energy management material and the inner liner is formed of a second foamed energy management material.
7. The helmet of claim 6 , wherein both the inward-facing surface of the outer liner and the outward-facing surface of the inner liner are substantially parallel to a portion of a sphere.
8. The helmet of claim 5 , wherein for each return spring of the plurality of return springs, at least one of the first end and the second end sits in a recess in one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner, the recess having a depth at least equal to a thickness of the return spring.
9. The helmet of claim 8 , wherein for at least one of the plurality of return springs, one of the first end and the second end is coupled to one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner by a fastener passing through the return spring and into the one of the inward-facing surface of the outer liner and the outward-facing surface of the inner liner.
10. The helmet of claim 9 , wherein each fastener is locked inside a different receiver, each receiver being embedded in one of the outer liner and the inner liner.
11. The helmet of claim 5 , wherein for at least one of the plurality of return springs, one of the first end and the second end is in-molded into one of the inner liner and the outer liner.
12. The helmet of claim 5 , further comprising:
an outer shell disposed on an outward-facing surface of the outer liner opposite the inward-facing surface of the outer liner, the outer shell comprising a shaped aperture; and
a branding element comprising a first portion passing through the shaped aperture of the outer shell, and a second portion disposed between the outer shell and the outward-facing surface of the outer liner.
13. The helmet of claim 5 , further comprising:
at least one leash coupling, each leash coupling comprising an upper end coupled to the outer liner, a lower end distal to the upper end and coupled to the inner liner, and a tether that is flexible, connects the upper end and the lower end, and passes through the inward-facing surface of the outer liner and the outward-facing surface of the inner liner;
wherein, for each of the at least one leash coupling, a majority of the tether is located in a cavity formed in at least one of the outer liner and inner liner.
14. The helmet of claim 13 , wherein, for each of the at least one leash coupling, the tether is between 10 mm and 15 mm long.
15. The helmet of claim 13 , wherein, for each of the at least one leash coupling, the upper end comprises an upper anchor coupled to an upper snap receptacle in-molded into the outer liner, and the lower end comprises a lower anchor coupled to a lower snap receptacle in-molded into the inner liner.
16. The helmet of claim 13 , wherein the tether of each leash coupling is composed of nylon.
17. The helmet of claim 13 , wherein at least one of the upper end and the lower end of each leash coupling is in-molded into at least one of the outer liner and the inner liner.