Patent ID: 8732868

Claim:
A helmet and/or helmet liner, having one or more internal flexibility sipes, said helmet and/or helmet liner comprising: at least a first bladder, chamber, or compartment having an inner surface; at least a second bladder, chamber, or compartment of a non-foamed plastic material and/or a non-blown rubber material located within and surrounded by said first bladder, chamber, or compartment, as viewed in a cross-section, and said a second bladder, chamber, or compartment having at least one cavity or void that least partially encloses at least one gas, as viewed in a cross-section, and an outer surface; and at least one said internal sipe of said helmet and/or helmet liner; wherein said at least one internal sipe is defined by at least a portion of said inner surface of said first bladder, chamber, or compartment and at least a portion of said outer surface of said second bladder, chamber, or compartment; and said surface portions defining said at least one internal sipe oppose each other and said first and second bladders, chambers, or compartments are configured such that said surface portions defining said at least one sipe are movable relative to each other in a sliding motion; and at least one attachment between said surface portions defining said at least one internal sipe, said at least one attachment being located at a central portion of said second bladder, chamber, or compartment.