CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND 
       [0003]    The present invention relates to a helmet for a bicycle. 
         [0004]    Helmets are worn by bicycle riders to protect the rider&#39;s head in the event of a crash. The helmet absorbs the shock of the crash instead of the rider&#39;s head. Road bicycles at competition levels exceed speeds of 25 miles per hour. If a rim breaks, or cars and other cyclists crash into the bicycle rider, the bicycle rider may fall to the ground in a violent and uncontrolled motion. The helmet protects the rider&#39;s head from unintended contact with the pavement, other cyclists, automobiles, etc. The helmet absorbs the shock impact instead of the rider&#39;s head. 
         [0005]      FIGS. 1 and 2  illustrate prior art bicycle helmets.  FIG. 1  illustrates a typical road bicycle helmet for recreational use. The helmet incorporates holes to provide air flow through the helmet so that the rider&#39;s head does not overheat during the bike ride. Unfortunately, due to the discontinuities formed by the apertures in the helmet as well as the rider&#39;s facial features, there is an increased coefficient of drag. Additionally, the back side of the helmet produces an area of low pressure which provides an overall rearward pressure differential to the rider&#39;s head. Although these sources of drag may be characterized in recreational riding as minute, by competition level standards, all minute sources of friction and drag may be considered to be significant. 
         [0006]    Referring to  FIG. 2 , a different type of bicycle helmet is shown. The bicycle helmet does not incorporate apertures for providing air flow through the helmet to cool down the rider&#39;s head during a bike ride. The helmet places aerodynamics over comfort. Additionally, the rider&#39;s face is pointed forward and exposed to the oncoming wind so that the rider&#39;s eyes may survey the upcoming terrain and avoid any obstacles in front of him/her without crashing. In this position, the tail portion is blended to the rider&#39;s back. Unfortunately, the bicycle rider must still look upwards so that the rider&#39;s face is in the direction of wind flow. The rider&#39;s face increases the coefficient of drag while the rider is looking forward. Also, the rider&#39;s neck will be strained for having to look up all the time. Additionally, when the rider looks downward, the tail portion is raised upward as shown by the hidden lines. The back side of the tail portion experiences low pressure which provides a net backward force on the tail portion thereby slowing the rider down. 
         [0007]    In both prior art  FIGS. 1 and 2 , the rider&#39;s head is cocked upward. During long rides, the rider must maintain this head up position so that the rider can keep track of obstacles in front of his/her path. Unfortunately, this is not a comfortable position. This up position creates neck strain thereby causing discomfort and potential long term physical problems to the rider. 
         [0008]    Accordingly, there is a need in the art for an improved bicycle helmet. 
       BRIEF SUMMARY 
       [0009]    The helmet discussed herein addresses the problems identified above, identified below and those that are known in the art. 
         [0010]    The helmet may define a leading portion located generally at the top of the rider&#39;s head when the helmet is worn by the rider. The leading portion may have a spherical or parabolic configuration so that when the rider is in the aggressive stance or posture and the rider&#39;s head is in the down position, the leading portion of the helmet initially contacts the oncoming wind and splits the wind above and below as well as from side-to-side around the helmet. Preferably, the wind flows in a laminar flow over the helmet so as to reduce the coefficient of drag. The helmet may further have a tail portion which extends from the back rear of the helmet and is blended to the back surface of the rider&#39;s back. Alternatively, the helmet may have a trailing surface which follows a contour of the rider&#39;s head. 
         [0011]    More particularly, an aerodynamic bicycle helmet for decreasing coefficient of drag when a head of a rider is in a down position is disclosed. The helmet may comprise a cushion, a strap and an exterior shell. The cushion may have a concave cavity for receiving the head of the rider. The strap may be attached to the cushion for maintaining the cushion on the head of rider in the event of a crash. The exterior shell may be disposed over the cushion. The exterior shell may have a leading portion with a parabolic configuration. The parabolic leading portion may be positioned on a top portion of the head of the rider when the helmet is worn by the rider. 
         [0012]    The helmet may further have an eye shield attached to the exterior shell for blocking wind to the eyes of the rider. The exterior shell may be continuous and smooth so that the exterior shell does not incorporate cooling vents. The parabolic leading portion may be symmetrical about a medial axis which is generally aligned to a spine of the rider when the helmet is worn by the rider. The external shell may have a tail portion aerodynamically blended to a back surface of the rider. Alternatively, the external shell may have a trailing surface which follows a contour of the rider&#39;s head. 
         [0013]    In an alternate embodiment, an aerodynamic bicycle helmet for decreasing coefficient of drag when a head of a rider is in a down position is disclosed. The helmet may comprise a cushion, a strap and an exterior shell. The cushion may have a concave cavity for receiving the head of the rider. The strap may be attached to the cushion for maintaining the cushion on the head of rider in the event of a crash. The exterior shell may be disposed over the cushion. The exterior shell may have a leading portion with a spherical configuration. The spherical leading portion may be positioned on a top portion of the head of the rider when the helmet is worn by the rider. 
         [0014]    The helmet may further have an eye shield attached to the exterior shell for blocking wind to the eyes of the rider. The exterior shell of the helmet may be continuous and smooth without any cooling vents. The spherical leading portion may be symmetrical about a medial axis which is generally aligned to a spine of the rider when the helmet is worn by the rider. The external shell may have a tail portion aerodynamically blended to a back surface of the rider. Alternatively, the external shell may have a trailing surface which follows a contour of the rider&#39;s head. 
         [0015]    A bicycle riding system is also disclosed. The system may comprise an aerodynamic helmet and a video system. 
         [0016]    The aerodynamic bicycle helmet may decrease coefficient of drag when a head of a rider is in a down position. In particular, the helmet may comprise a cushion, a strap and an exterior shell. The cushion may have a concave cavity for receiving the head of the rider. The strap may be attached to the cushion for maintaining the cushion on the head of rider in the event of a crash. The exterior shell may be disposed over the cushion. The exterior shell may have a leading portion with a spherical or a parabolic configuration. The leading portion may be positioned on a top portion of the head of the rider when the helmet is worn by the rider. 
         [0017]    The bicycle may comprise a front wheel, a rear wheel, a frame with the front and rear wheels attached to the frame, a handlebar attached to the front wheel and the frame for steering the front wheel, and a video system with a camera positioned to provide a front view of the bicycle path and a video screen to provide the front view of the bicycle path. The video screen may be mounted to the handlebar so that the rider can view the video screen while the rider maintains his/her head in the down position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
           [0019]      FIG. 1  is an illustration of a prior art road bicycle helmet; 
           [0020]      FIG. 2  is an illustration of another embodiment of a prior art road bicycle helmet; 
           [0021]      FIG. 3  is a side view of a parabolic shaped helmet; 
           [0022]      FIG. 4  is a front view of the helmet shown in  FIG. 3 ; 
           [0023]      FIG. 5  is a side view of a second embodiment of a spherical shaped helmet; 
           [0024]      FIG. 6  is a front view of the helmet shown in  FIG. 5 ; 
           [0025]      FIG. 7  is a perspective view of a first embodiment of a bicycle handlebar video system; 
           [0026]      FIG. 8  is a second embodiment of the bicycle handlebar video system; and 
           [0027]      FIG. 9  is a third embodiment of the bicycle handlebar video system. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring now to the drawings, improved bicycle helmets  10 ,  12  are shown in  FIGS. 3-6 . When the rider&#39;s head is in the downward position, the exterior shell  14  forms an aerodynamic leading portion (i.e., parabolic configuration or spherical configuration) to split the air flow  15  around the helmet  10 ,  12  in a laminar fashion thereby reducing the coefficient of drag caused by the helmet  10 ,  12  and rider&#39;s head. The rider can maintain his/her head in the downward position by installing a bicycle handlebar video system  20  as described in U.S. patent application Ser. No. 12/257,124, filed on Oct. 23, 2008, the entire contents of which is expressly incorporated herein by reference. In this manner, the rider does not have to intermittently look up to view obstacles in front of the rider&#39;s bicycle path. Rather, the rider may look down at a screen  16  that displays a frontal view of the rider&#39;s bicycle path, as shown in  FIGS. 7-9 . In particular, a camera  18  may be pointed forward and feed images to the screen  16 . The rider may look down at the screen  16  to obtain a picture of the bicycle&#39;s forward path so that the rider can make adjustments to the path as necessary to avoid obstacles. Accordingly, the improved bicycle helmets  10 ,  12  along with the bicycle handlebar video system  20  allows the rider to maintain a comfortable head down position and gain the benefit of an aerodynamic shaped helmet  10 ,  12 . 
         [0029]    Referring now to  FIGS. 3 and 4 , a first embodiment of the helmet  10  is shown. The helmet  10  incorporates a parabolic leading portion  26 . When the rider is riding the bicycle  24  and the rider&#39;s head is in the downward position, the parabolic leading portion  26  initially contacts the oncoming wind  15  and splits the wind flow around the helmet  10  as shown by arrows  28   a, b  above and below the helmet  10 . When the rider&#39;s head is in the downward position, as shown in  FIG. 3 , the upper and lower profiles  30   a, b  of the helmet  10  are generally symmetrical about axis  32  which may be generally parallel to a forward direction  34  of the bicycle  24 . Also, a tail portion  36  of the upper profile  30   a  may generally blend with a back surface  38  of the rider  40 . A low pressure is not created behind the rider&#39;s helmet  10  when the rider&#39;s head is in the downward position. The air  15  flows over the upper profile  30   a  and the back surface  38  of the rider  40 . The rider does not have to lift up his/her head to look forward since the rider can view the video screen  16  of the bicycle handlebar video system  20  mounted to a handlebar  22 , as shown in  FIGS. 7-9 . 
         [0030]    More particularly, referring back to  FIG. 3 , during a road race, the rider  50  may be in an aggressive riding posture. In particular, the back of the rider is hunched forward in its lowermost position so that the collective frontal profile of the rider  50  and bicycle  24  is minimized to reduce the coefficient of drag. The rider&#39;s head is in the down position so that the neck of the rider is generally straight with the spine of the rider. This allows the rider to reduce or eliminate any neck pain that might be caused by looking up to view the terrain in front of the rider&#39;s path. The rider  50  can view the forward view by way of the bicycle handlebar video system  20  which is discussed herein. In this aggressive riding posture, the rider has a minimal frontal profile to reduce the coefficient of drag. Additionally, the helmet  10  of the rider  50  is shaped to further reduce the coefficient of drag. In particular, when the rider  50  is in the aggressive posture with his/her head in the down position as shown in  FIG. 3 , the helmet  10  may have a leading portion  26  that has a parabolic configuration. The parabolic configuration of the leading portion  26  of the helmet  10  allows the oncoming wind  15  to separate laminarly or less turbulently over the helmet  10  thereby further reducing the coefficient of drag. It is contemplated that the leading portion  26  of the helmet  10  is generally located at the top of the rider&#39;s head so that the parabolic leading portion  26  of the helmet  10  initially contacts the oncoming wind  15 . 
         [0031]    As the wind  15  proceeds backward, the wind  15  is split above and below the helmet  10  as shown by arrow  28   a, b . Preferably, the wind  15  maintains laminar flow over the helmet  10 . The air flow shown by directional arrow  28   a  flows over the tail portion  36  of the helmet  10  and over the back surface  38  of the rider  50 . Preferably, the tail portion  36  is blended with the back surface  38  of the rider  50  so that the wind  15  maintains laminar flow over the transition between the tail portion  36  of the helmet  10  and the back surface  38  of the rider  50 . For the wind  15  that flows below the helmet  10  shown by directional arrow  28   b , the air flows over the transparent face mask  52  that is attached to the helmet  10 . 
         [0032]    Referring now to  FIG. 4 , a front view of the helmet  10  is shown. The leading portion  26  is located at the top of the rider&#39;s head. Also, the left and right sides of the helmet  10  are symmetrical about medial axis  32 . The helmet  10  additionally has a strap  54  for retaining the helmet  10  on the rider&#39;s head in the event of a crash. The strap  54  extends downward from the left and right sides of the helmet  10  and is attached to each other by the clip  56  below the rider&#39;s chin. The helmet  10  may also be symmetrical about axis  32  when viewed from the front (see  FIG. 4 ) or side (see  FIG. 3 ). In this manner, the wind  15  may be separated by the parabolic leading portion  26  of the exterior shell  14  of the helmet  10  front-to-back and side-to-side. 
         [0033]    Referring now to  FIGS. 5 and 6 , a second embodiment of the helmet  12  is shown. Instead of a parabolic leading portion, the leading portion  44  has a spherical configuration. The wind  15  contacts the leading portion  44  and is split up by the spherical leading portion  44 . When the rider  50  is in the aggressive position shown in  FIG. 5 , and the rider&#39;s head is looking downward, the oncoming wind  15  initially contacts the spherical leading portion  44 . The oncoming wind  15  is diverted above and below the helmet  12  as shown by directional arrow  46   a , b. The helmet  12  does not have a rear tail portion  36  that blends with the rider&#39;s back surface  38 . Rather, the trailing surface  57  follows the contour of the rider&#39;s head. This minimizes any low pressure behind the helmet  12  caused by the oncoming wind  15 . The oncoming wind  15  flowing in the direction of arrow  46   a  traverses over the helmet  12  and over the back surface  38  of the rider  50 . The oncoming wind  15  also flows under the helmet  12  and under the face mask shown by directional arrow  46   b.    
         [0034]    Referring now to  FIG. 6 , the spherical leading portion  44  is also generally located at the top of the rider&#39;s head. The wind  15  when the rider  50  is in the aggressive position with his/her head in the down position contacts the spherical leading portion  44  and splits to the left and right sides of the helmet  12  as shown by arrows  58   a, b . Preferably, the left or right sides of the helmet  12  are symmetrical about medial axis  48 . Additionally, the helmet  12  may also be symmetrical about the medial axis  48  so that the wind is split above and below the helmet  12 . The helmet  12  may also be retained on the rider&#39;s head by way of straps  54  and clip  56 , as discussed above. 
         [0035]    Referring now to  FIG. 7 , the bicycle handlebar video system  20  is shown. The screen  16  is shown as being integrated into the handlebar  22 . However, it is also contemplated that the screen  16  may be mounted to the handlebar  22  by way of a flexible shaft  58  as shown in  FIG. 8 . The rider can adjust the position of the screen  16  so that the screen  16  is in the rider&#39;s line of sight when the rider&#39;s head is in the downward position. The camera  18  is also shown being in a fixed position on the handlebar  22 . However, it is also contemplated that the camera  18  may be mounted so as to be adjustable as shown in  FIG. 9 . The rider can adjust the direction of the camera&#39;s line of sight as needed. The bicycle handle bar video system  20  enables the rider to maintain his/her head in the downward position as shown in  FIGS. 3 and 5  while riding the road bicycle  24 . These and other aspects of the bicycle handlebar video system  20  are discussed in U.S. patent application Ser. No. 12/257,124, filed on Oct. 23, 2008, the entire contents of which is expressly incorporated herein by reference. 
         [0036]    The helmets  10 ,  12  discussed herein may have an exterior shell, a padding disposed under the exterior shell, straps  54  and clips  56  attached to the padding or exterior shell to retain the helmets  10 ,  12  on the rider&#39;s head in event of a crash, and a face mask  52 . The face mask  52  may be transparent and may also be pivoted up so that the rider&#39;s eyes are exposed to the environment. Additionally, the face mask  52  may be pivoted down so that the wind  15  does not blow air on the rider&#39;s eyes. In this manner, the rider&#39;s eyes do not become dry which may be a problem when the rider  50  is wearing contact lenses. Additionally, the face mask  52  extends the potential laminar air flow below the helmet  10 ,  12  during use. The exterior shell of the helmet  10 ,  12  may be fluid and have no apertures for providing cooling features to the helmet  10 ,  12 . 
         [0037]    Referring back to  FIG. 3 , the parabolic shaped helmet  10  may also be modified so as to have a trailing surface  57   a  instead of a trailing portion  36 . The trailing surface  57   a  may behave in the same manner as that described in relation to  FIGS. 5 and 6 . Moreover, referring back to  FIG. 5 , the spherical shaped helmet  12  may have a trailing portion  36   a  instead of a trailing surface  57 . The trailing portion  36   a  may behave in the same manner as that described in relation to  FIGS. 3 and 4 . 
         [0038]    The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of constructing the strap and clip. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.
An aerodynamic bicycle helmet for decreasing coefficient of drag when a head of a rider is in a down position is disclosed. The helmet may comprise a cushion with a concave cavity for receiving the head of the rider; a strap attached to the cushion for maintaining the cushion on the head of rider in the event of a crash; an exterior shell disposed over the cushion, the exterior shell having a leading portion with a spherical or a parabolic configuration, the leading portion positioned on a top portion of the head of the rider when the helmet is worn by the rider.