Helmet structures and methods

Abstract

A personal protective item, such as a helmet, includes a substrate formed of a hexagonal structure comprising a plurality of hexagonal tubes, each hexagon tube having a first end and a second end and being formed by a plurality of walls, the first and second ends being defined by edges of the plurality of walls. A cylindrical end cap is provided on at least some of the edges of the plurality of walls. The personal protective item may further comprise supporting columns along the hexagonal tubes where the walls of adjacent hexagonal tubes meet. A pad for providing user comfort may also be provide., the pad comprising a plate that is deflectable relative to a substrate of the personal protective time, the pad being coupled to the substrate by one or more constant force springs. Parts of the protective item may be joined using splines and grooves.

What is claimed is: 
     
         1 . A personal protective item, comprising:
 a hexagonal structure comprising a plurality of hexagonal tubes, each hexagon tube having a first end and a second end and being formed by a plurality of walls, the first and second ends being defined by edges of the plurality of walls; and   a cylindrical end cap on at least some of the edges of the plurality of walls.   
     
     
         2 . The personal protective item of  claim 1 , wherein the hexagonal tubes having cylindrical end caps are open adjacent to the end caps for ventilation. 
     
     
         3 . The personal protective item of  claim 1 , further comprising an end wall coupled to at least some of the edges of the walls to close the ends of at least some of the hexagonal tubes, the edges of the walls of the hexagonal tubes adjacent to the end wall not having cylindrical end caps. 
     
     
         4 . The personal protective item of  claim 1 , further comprising supporting columns along the hexagonal tubes where the walls of adjacent hexagonal tubes meet. 
     
     
         5 . The personal protective item of  claim 4 , wherein the supporting columns taper from the first end to the second end. 
     
     
         6 . The personal protective item of  claim 4 , wherein a diameter of the supporting columns varies across the personal protective item. 
     
     
         7 . The personal protective item of  claim 4 , wherein a wherein the cross-sectional shape of at least one column is modified for printability. 
     
     
         8 . The personal protective item of  claim 1 , wherein the end caps and support columns have circular or elliptical cross-sections. 
     
     
         9 . The personal protective item of  claim 8 , wherein the end caps and support columns have cross-section shapes modified for improved 3d printability by adding or removing faces. 
     
     
         10 . The personal protective item of  claim 1 , wherein the personal protective item is assembled from at least a first part and a second part, the first part having a spline defined thereon and the second part having a groove defined therein for receiving the spline. 
     
     
         11 . The personal protective item of  claim 1 , wherein the personal protective item is assembled from at least a first part and a second part and an extrinsic spline, the first part having groove defined therein for receiving the spline and the second part having a groove defined therein for receiving the spline. 
     
     
         12 . The personal protective item of  claim 1 , further comprising a pad for providing user comfort, the pad comprising a plate that is deflectable relative to a substrate of the personal protective time, the pad being coupled to the substrate by one or more constant force springs. 
     
     
         13 . The personal protective item of  claim 12 , wherein the pad comprises a number of posts mounted to the plate, the posts being received by post holes defined in the substrate. 
     
     
         14 . A personal protective item, comprising:
 an inner wall having a first aperture defined therein;   an outer wall having a second aperture defined therein;   a honeycomb structure located between the inner wall and the outer wall, the honeycomb structure comprising a plurality of hexagonal tubes having first ends and second ends, the first and second ends of a first group of the hexagonal tubes being exposed through the first aperture and the second aperture; and   end caps located on the first and second ends of the first group of hexagonal tubes.   
     
     
         15 . The personal protective item of  claim 14 , wherein the first and second ends of a second group of hexagonal tubes are coupled to the inner wall and the outer wall respectively without having end caps. 
     
     
         16 . The personal protective item of  claim 14 , wherein the hexagonal tubes comprise tube walls, the personal protective item further comprising:
 supporting columns along the hexagonal tubes where the tube walls of adjacent hexagonal tubes meet.   
     
     
         17 . The personal protective item of  claim 16 , wherein the supporting columns taper along the length of the hexagonal tubes. 
     
     
         18 . The personal protective item of  claim 16 , wherein a diameter of the supporting columns varies across the personal protective item. 
     
     
         19 . The personal protective item of  claim 14 , wherein the personal item is assembled from at least a first part and a second part, the first part having a spline defined thereon and the second part having a groove defined therein for receiving the spline. 
     
     
         20 . The personal protective item of  claim 19  further comprising a pad for providing user comfort, the pad comprising a plate that is deflectable relative to a substrate of the personal protective time, the pad being coupled to the substrate by one or more constant force springs.