Abstract: A helmet with an outer shell, an inner liner, a plurality of vents, and an occipital cliff is disclosed. The outer shell includes an outer surface made up of a first and second surface, the first and second surfaces joined by a drop-off running across the outer surface from a left side of the helmet to a right side of the helmet. A majority of the drop-off is closer to a coronal plane bisecting the helmet than it is to the rear of the helmet. The drop-off is contained within a posterior section of the helmet defined by the coronal plane. The first surface defines a top of the drop-off and the second surface defines a bottom of the drop-off, such that the drop-off has a height. The occipital cliff is located at the rear end of the helmet and is approximately perpendicular to the second surface proximate the drop-off.

Abstract: A helmet for rotational energy management can include an outer energy management layer comprising an outer surface and an inner surface opposite the outer surface. The inner surface can comprise a first slidable finish comprising a first glaze comprising a thickness less than or equal to 2 millimeters (mm). An inner energy management layer can be disposed within the outer energy management layer and further comprise an outer surface oriented towards the outer energy management layer and an inner surface opposite the outer surface. The outer surface can comprise a second slidable finish that directly contacts the first slidable finish. The second slidable finish can comprise a second glaze comprising a thickness less than or equal to 2 mm. A space between the first slidable finish and the second slidable finish can be devoid of a lubricant and devoid of any interstitial slip layer.

Abstract: A helmet with an outer shell, an inner liner, a plurality of vents, and an occipital cliff is disclosed. The outer shell includes an outer surface made up of a first and second surface, the first and second surfaces joined by a drop-off running across the outer surface from a left side of the helmet to a right side of the helmet. A majority of the drop-off is closer to a coronal plane bisecting the helmet than it is to the rear of the helmet. The drop-off is contained within a posterior section of the helmet defined by the coronal plane. The first surface defines a top of the drop-off and the second surface defines a bottom of the drop-off, such that the drop-off has a height. The occipital cliff is located at the rear end of the helmet and is approximately perpendicular to the second surface proximate the drop-off.

Abstract: A helmet for rotational energy management can include an outer energy management layer comprising an outer surface and an inner surface opposite the outer surface. The inner surface can comprise a first slidable finish comprising a first glaze comprising a thickness less than or equal to 2 millimeters (mm). An inner energy management layer can be disposed within the outer energy management layer and further comprise an outer surface oriented towards the outer energy management layer and an inner surface opposite the outer surface. The outer surface can comprise a second slidable finish that directly contacts the first slidable finish. The second slidable finish can comprise a second glaze comprising a thickness less than or equal to 2 mm. A space between the first slidable finish and the second slidable finish can be devoid of a lubricant and devoid of any interstitial slip layer.

Abstract: A helmet can include an outer shell including a faceport, a first segment including a longitudinal ridge extending from a front of the helmet to a rear of the helmet, a gap disposed along the edge of the first segment, and a second segment offset from the first segment by the gap. A hinged zone can be formed by an elastomeric material disposed within the gap and coupled to the first segment and the second segment of the outer shell. The hinged zone can elastically flex in a radial direction towards a center of the helmet. An energy absorbing liner can be coupled to an inner surface of the outer shell, and an open space can be formed between an inner surface of the hinged zone and an outer surface of the energy absorbing liner.

Abstract: A helmet with an outer shell, an inner liner, a plurality of vents, and an occipital cliff is disclosed. The outer shell includes an outer surface made up of a first and second surface, the first and second surfaces joined by a drop-off running across the outer surface from a left side of the helmet to a right side of the helmet. A majority of the drop-off is closer to a coronal plane bisecting the helmet than it is to the rear of the helmet. The drop-off is contained within a posterior section of the helmet defined by the coronal plane. The first surface defines a top of the drop-off and the second surface defines a bottom of the drop-off, such that the drop-off has a height. The occipital cliff is located at the rear end of the helmet and is approximately perpendicular to the second surface proximate the drop-off.

Abstract: A protective helmet for rotational energy management may include an outer protective shell including an outer surface and an inner surface, a portion of which may be spherically shaped. An inner protective shell may be disposed within the outer protective shell and include a spherically shaped outer surface oriented towards the inner surface of the outer protective shell. A surface area of the outer surface of the inner protective shell may be less than a surface area of the inner surface of the outer protective shell. A first elastomer member may extend through a first channel through the outer protective shell and the inner protective shell. A boundary nub may include a spherical shape and be integrally formed with the inner protective shell at a front lower edge of the inner protective shell.

Abstract: A helmet for rotational energy management can include an outer energy management layer comprising an outer surface and an inner surface opposite the outer surface. The inner surface can comprise a first slidable finish comprising a first glaze comprising a thickness less than or equal to 2 millimeters (mm). An inner energy management layer can be disposed within the outer energy management layer and further comprise an outer surface oriented towards the outer energy management layer and an inner surface opposite the outer surface. The outer surface can comprise a second slidable finish that directly contacts the first slidable finish. The second slidable finish can comprise a second glaze comprising a thickness less than or equal to 2 mm. A space between the first slidable finish and the second slidable finish can be devoid of a lubricant and devoid of any interstitial slip layer.

Abstract: A helmet can include an outer shell including a faceport, a first segment including a longitudinal ridge extending from a front of the helmet to a rear of the helmet, a gap disposed along the edge of the first segment, and a second segment comprising offset from the first segment by the gap. A hinged zone can be formed by an elastomeric material disposed within the gap and coupled to the first segment and the second segment of the outer shell. The hinged zone can elastically flex in a radial direction towards a center of the helmet. An energy absorbing liner can be coupled to an inner surface of the outer shell, and an open space can be formed between an inner surface of the hinged zone and an outer surface of the energy absorbing liner.

Abstract: A helmet comprising an outer shell and a chin bar collar is disclosed. The outer shell comprises an interior surface and an open front portion. The chin bar collar comprises a chin guard and a collar segment forming a continuous loop. The collar segment is coupled to the interior surface of the outer shell. A majority of the collar segment is positioned within an interior space of the outer shell, and a majority of the chin guard is positioned outside the interior space of the outer shell. The outer shell may include at least two coupling points, at least one on each side of the open front portion, coupling the chin bar collar to the outer shell. The helmet may include at least one bracket coupled to the interior surface of the outer shell. The chin bar collar may be releasably coupled to the interior surface of the outer shell.