Systems and methods for attenuating rotational acceleration of the head

Abstract

In one embodiment, a system for attenuating rotation acceleration of the head includes a protective helmet adapted to be worn on the head of a user, the helmet including an outer shell having an inner surface, an inner liner provided within the shell, the liner comprising one or more pads, and means for enabling the shell to rotate relative to the user's head, the means excluding cell-based foam.

1 . A protective helmet adapted to be worn on the head of a user, the helmet comprising:
 an outer shell having an inner surface;   an inner liner provided within the shell, the liner comprising one or more pads; and   means for enabling the shell to rotate relative to the user's head, the means excluding cell-based foam.   
     
     
         2 . The helmet of  claim 1 , wherein the shell is made of an acrylonitrile butadiene styrene or polycarbonate alloy material. 
     
     
         3 . The helmet of  claim 1 , wherein the means for enabling the shell to rotate comprise means for enabling at least one pad to slide within and relative to the shell. 
     
     
         4 . The helmet of  claim 3 , wherein the means for enabling the at least one pad to slide comprise a raceway formed on the inner surface of the shell along which the at least one pad can slide. 
     
     
         5 . The helmet of  claim 4 , wherein the raceway is defined by first and second ribs that confine the at least one pad to the raceway. 
     
     
         6 . The helmet of  claim 5 , wherein one or both of the raceway and the at least one pad is provided with a low-friction material that facilitates sliding of the at least one pad relative to the raceway. 
     
     
         7 . The helmet of  claim 4 , wherein the raceway is horizontally aligned within the shell so that the at least one pad can laterally slide from the front of the shell toward the back of the shell and vice versa. 
     
     
         8 . The helmet of  claim 3 , wherein the means for enabling the at least one pad to slide comprise a rail that guides the at least one pad. 
     
     
         9 . The helmet of  claim 8 , wherein the rail is provided on the inner surface of the shell and the at least one pad comprises a groove adapted to receive the rail. 
     
     
         10 . The helmet of  claim 8 , wherein the rail is provided on an outer surface of the at least one pad and the shell comprises a groove adapted to receive the rail. 
     
     
         11 . The helmet of  claim 3 , wherein the means for enabling the at least one pad to slide comprise an isolation bushing including at least one compression spring. 
     
     
         12 . The helmet of  claim 3 , further comprising means for slowing the rotation of the shell and dissipating rotational force that caused the rotation. 
     
     
         13 . The helmet of  claim 12 , wherein the means for slowing comprise a force dissipation pad that is securely affixed to the inner surface of the shell and that is adapted to abut the at least one pad once it has slid a predetermined distance relative to the shell. 
     
     
         14 . The helmet of  claim 13 , wherein the force dissipation pad comprises a compression region that is adapted to compress to dissipate the rotational force. 
     
     
         15 . The helmet of  claim 14 , wherein the compression region comprises vertical grooves formed in a lateral edge of the force dissipation pad. 
     
     
         16 . The helmet of  claim 14 , wherein the force dissipation pad is a rear pad attached to a rear of the shell and wherein the at least one pad comprises a lateral pad positioned on a lateral side of the shell. 
     
     
         17 . The helmet of  claim 16 , wherein the lateral pad comprises vertical ribs that easily yield to horizontal shear forces to further dissipate the rotational force. 
     
     
         18 . The helmet of  claim 12 , wherein the means for slowing comprise at least one compression spring provided within the shell. 
     
     
         19 . The helmet of  claim 1 , wherein the means for enabling the shell to rotate comprise at least one pad that includes a three-dimensional spacer fabric comprising spaced layers of material that are connected by fibers that extend between the layers in a direction generally perpendicular to the layers, the fibers being adapted to absorb lateral and rotational shear forces. 
     
     
         20 . The helmet of  claim 19 , wherein the three-dimensional spacer fabric is impregnated with a cured resin that provides rigidity to the fabric. 
     
     
         21 . The helmet of  claim 20 , wherein the resin comprises one or more of thermoplastic polyurethane, poly caprolactum (nylon), or epoxy resin. 
     
     
         22 . The helmet of  claim 19 , wherein the spaced layers are woven layers of material. 
     
     
         23 . The helmet of  claim 22 , wherein the woven layers are weaves of glass or polymeric fibers or yarns. 
     
     
         24 . The helmet of  claim 19 , wherein the fibers that extend between the layers are glass or polymer fibers. 
     
     
         25 . The helmet of  claim 19 , wherein the fibers that extend between the layers are curved. 
     
     
         26 . The helmet of  claim 19 , wherein the at least one pad further comprises a layer of high-density foam. 
     
     
         27 . The helmet of  claim 26 , wherein the high-density foam forms an inner layer adapted to contact the user's head and the three-dimensional spacer fabric forms an outer layer that is adapted to attach to the inner surface of the shell. 
     
     
         28 . The helmet of  claim 19 , wherein the at least one pad further comprises another three-dimensional spacer fabric and wherein a first of the three-dimensional spacer fabrics forms an inner layer adapted to contact the user's head and a second of the three-dimensional spacer fabrics forms an outer layer that is adapted to attach to the inner surface of the shell. 
     
     
         29 . An inner liner adapted for use with a shell of a protective helmet, the liner comprising:
 at least one pad that includes a three-dimensional spacer fabric comprising spaced layers of material that are connected by fibers that extend between the layers in a direction generally perpendicular to the layers, the fibers being adapted to absorb lateral and rotational shear forces.   
     
     
         30 . The helmet of  claim 29 , wherein the three-dimensional spacer fabric is impregnated with a cured resin that provides rigidity to the fabric. 
     
     
         31 . The helmet of  claim 30 , wherein the resin comprises one or more of thermoplastic polyurethane, poly caprolactum (nylon), or epoxy resin. 
     
     
         32 . The helmet of  claim 29 , wherein the spaced layers are woven layers of material. 
     
     
         33 . The helmet of  claim 32 , wherein the woven layers are weaves of glass or polymeric fibers or yarns. 
     
     
         34 . The helmet of  claim 29 , wherein the fibers that extend between the layers are glass or polymer fibers. 
     
     
         35 . The helmet of  claim 29 , wherein the fibers that extend between the layers are curved. 
     
     
         36 . The helmet of  claim 29 , wherein the at least one pad further comprises a layer of high-density foam. 
     
     
         37 . The helmet of  claim 36 , wherein the high-density foam forms an inner layer adapted to contact the user's head and the three-dimensional spacer fabric forms an outer layer that is adapted to attach to the inner surface of the shell. 
     
     
         38 . The helmet of  claim 29 , wherein the at least one pad further comprises another three-dimensional spacer fabric and wherein a first of the three-dimensional spacer fabrics forms an inner layer adapted to contact the user's head and a second of the three-dimensional spacer fabrics forms an outer layer that is adapted to attach to the inner surface of the shell. 
     
     
         39 . A method for attenuating rotational acceleration of the head, the method comprising:
 wearing a protective helmet comprising an outer shell, an inner liner having one or more pads, and means for enabling the shell to rotate relative to the head, the means excluding cell-based foam.   
     
     
         40 . The method of  claim 39 , wherein the means for enabling the shell to rotate comprise means for enabling at least one pad to slide within and relative to the shell. 
     
     
         41 . The method of  claim 39 , wherein the means for enabling the shell to rotate comprise at least one pad that includes a three-dimensional spacer fabric comprising spaced layers of material that are connected by fibers that extend between the layers in a direction generally perpendicular to the layers, the fibers being adapted to absorb lateral and rotational shear forces.