Bicycle helmet with vent

Abstract

A bicycle helmet can include at least one ventilation opening and an exhaust port such that airflow enters the helmet through the ventilation opening and exits through the exhaust port, providing ventilation for a user. The orientation and location of the ventilation openings can reduce the aerodynamic drag of the helmet by delaying flow separation from the surface of the helmet and prevent airflow stagnation around the user's shoulders and neck.

What is claimed is: 
     
         1 . A bicycle helmet comprising:
 a main unit having a cavity configured to receive a user's head, said main unit comprising a shell and a body, said main unit defining a front surface and a rear surface which have a parabolic profile when viewed from above when the user is in an aerodynamic position with the user's head lowered;   a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rearward of a widest vertical cross section of the main unit, said ventilation opening having a height, a width, and a depth, and an exhaust port in a rear portion of the main unit wherein the height of the ventilation opening transverse to a local flow direction at said ventilation opening is the largest dimension of the ventilation opening;   wherein said ventilation mechanism provides an airflow through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.   
     
     
         2 . The bicycle helmet of  claim 1 , wherein the local flow direction at the ventilation opening is perpendicular to the height of the ventilation opening. 
     
     
         3 . The bicycle helmet of  claim 1 , wherein said exhaust port comprises at least one opening in the rear of the main unit. 
     
     
         4 . The bicycle helmet of  claim 1 , where said exhaust port is located below a trailing top edge of the helmet. 
     
     
         5 . The bicycle helmet of  claim 1 , wherein said exhaust port is located below a trailing bottom edge of the helmet. 
     
     
         6 . The bicycle helmet of  claim 1 , wherein said ventilation opening is located forward of a plane defined by flow separation from the surface of the helmet. 
     
     
         7 . The bicycle helmet of  claim 1 , wherein the height of said ventilation opening is substantially more than the width of said ventilation opening. 
     
     
         8 . The bicycle helmet of  claim 7 , wherein the height of said ventilation opening is 6 times the width. 
     
     
         9 . The bicycle helmet of  claim 7 , wherein the height of said ventilation opening is 8 times the width. 
     
     
         10 . The bicycle helmet of  claim 7 , wherein the height of said ventilation opening is 6-8 times the width. 
     
     
         11 . The bicycle helmet of  claim 1 , wherein a leading edge of said ventilation opening is formed in line with the side surface of the helmet. 
     
     
         12 . The bicycle helmet of  claim 1 , wherein a leading edge of said ventilation opening is recessed inward from the side surface of the helmet. 
     
     
         13 . The bicycle helmet of  claim 1 , wherein said rear surface tapers toward the rear of said body. 
     
     
         14 . The bicycle helmet of  claim 1 , wherein said helmet has a substantially teardrop shape. 
     
     
         15 . The bicycle helmet of  claim 13 , wherein said rear surface is bobbed to reduce the length of said body. 
     
     
         16 . The bicycle helmet of  claim 1  further comprising a top surface, wherein said top surface does not comprise any openings. 
     
     
         17 . The bicycle helmet of  claim 1  further comprising a front surface, wherein said front surface does not comprise any openings. 
     
     
         18 . The bicycle helmet of  claim 1  further comprising a substantially hollow rear portion of the helmet extending from the back of a user's head to the exhaust port, said rear portion formed such that a bottom surface of the rear portion is substantially flat and an upper surface of the rear portion is curved. 
     
     
         19 . The bicycle helmet of  claim 1 , wherein said ventilation opening is located forward of a plane located half of the distance rearward from the widest cross section of the helmet to the rear of the helmet. 
     
     
         20 . The bicycle helmet of  claim 1 , wherein said ventilation opening is located forward of a plane located two-thirds of the distance rearward from the widest cross section of the helmet to the rear of the helmet as measured from the widest cross section of the helmet. 
     
     
         21 . A bicycle helmet comprising:
 a body having a cavity configured to receive a user's head;   a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rearward of the widest cross section of the main unit and an exhaust port formed substantially in a rear portion of the main unit;   wherein said ventilation mechanism provides a flow of air through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.   
     
     
         22 . A method for reducing aerodynamic drag while operating a bicycle, the method comprising:
 providing an aerodynamic bicycle helmet comprising a body having a cavity configured to receive a user's head, a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said helmet rearward of the widest cross section of the main unit and an exhaust port formed in a rear portion of the main unit;   placing said helmet on the user's head;   orienting the user's head while operating a bicycle such that a local airflow direction at the ventilation opening is perpendicular to said opening; and   allowing said airflow to enter the helmet through said ventilation opening and exit the helmet through said exhaust port.