Helmet with an air trip

Abstract

A helmet includes an energy absorbing layer and an outer shell mounted to the energy absorbing layer. The outer shell includes an air trip in the form of a continuous groove that extends from a bottom left side of the helmet to a bottom right side of the helmet.

What is claimed is: 
     
         1 . A helmet comprising:
 an energy absorbing layer; and   an outer shell mounted to the energy absorbing layer, wherein the outer shell includes an air trip in the form of a continuous groove that extends from a bottom left side of the helmet to a bottom right side of the helmet.   
     
     
         2 . The helmet of  claim 1 , wherein the continuous groove has a u-shaped cross-section. 
     
     
         3 . The helmet of  claim 1 , wherein the helmet includes a front and a back, and wherein the air trip is positioned closer to the front of the outer shell than a position of a natural laminar-to-turbulent airflow transition region of the outer shell. 
     
     
         4 . The helmet of  claim 1 , wherein the air trip has a first curved transition that transitions from the outer shell into a front portion of the air trip. 
     
     
         5 . The helmet of  claim 4 , wherein the air trip has a second curved transition that transitions from the outer shell into a back portion of the air trip. 
     
     
         6 . The helmet of  claim 4 , wherein the first curved transition has a first radius of curvature that differs from a second radius of curvature of a bottom of the groove. 
     
     
         7 . The helmet of  claim 5 , wherein the first curved transition has a first radius of curvature and the second curved transition has a second radius of curvature, and wherein the first radius of curvature is the same as the second radius of curvature. 
     
     
         8 . The helmet of  claim 1 , wherein the air trip is at an angle of 90 degrees relative to an outer surface of the outer shell of the helmet. 
     
     
         9 . The helmet of  claim 1 , wherein air trip is at an angle of greater than or less than 90 degrees relative to the outer shell of the helmet. 
     
     
         10 . The helmet of  claim 1 , wherein a thickness of the outer shell is constant over the entire outer shell, including at the air trip. 
     
     
         11 . A method of making a helmet, the method comprising:
 forming an outer shell with an air trip, wherein the air trip comprises a continuous groove that extends from a bottom left side of the outer shell to a bottom right side of the outer shell;   forming an energy absorbing layer that includes an energy absorbing layer groove that is configured to receive the air trip; and   mounting the energy absorbing layer to the outer shell.   
     
     
         12 . The method of  claim 11 , wherein forming the air trip comprises forming the continuous groove to have a u-shaped cross section. 
     
     
         13 . The method of  claim 11 , further comprising determining a location on the outer shell of a natural laminar-to-turbulent airflow transition region. 
     
     
         14 . The method of  claim 13 , wherein forming the air trip comprises positioning the air trip at a location on the outer shell that is closer to a front of the helmet than the natural laminar-to-turbulent airflow transition region. 
     
     
         15 . The method of  claim 11 , wherein forming the air trip includes forming a first curved transition that transitions from the outer shell into a front portion of the air trip and forming a second curved transition that transitions from the outer shell into a back portion of the air trip. 
     
     
         16 . The method of  claim 15 , wherein the first curved transition is formed with a first radius of curvature and a bottom of the groove is formed with a second radius of curvature that differs from the first radius of curvature. 
     
     
         17 . The method of  claim 15 , wherein the first curved transition is formed to have a first radius of curvature and the second curved transition is formed to have a second radius of curvature, and wherein the first radius of curvature is the same as the second radius of curvature. 
     
     
         18 . The method of  claim 11 , wherein forming the air trip includes positioning the air trip at an angle of 90 degrees relative to an outer surface of the outer shell of the helmet. 
     
     
         19 . The method of  claim 11 , wherein forming the air trip includes positioning the air trip at an angle of less than or greater than 90 degrees relative to an outer surface of the outer shell of the helmet. 
     
     
         20 . The method of  claim 11 , further comprising forming the outer shell such that a thickness of the outer shell is constant over the entire outer shell, including at the air trip.