Abstract:
A safety handlebar is described in which telescopic handgrips are provided at the two opposing outer ends of the tubular frame of the handlebar. In each embodiment described, a shaft and an outer cover are locked together for telescopic movement on each tubular outer end of the handlebar frame. A bias member in the form of a coil spring biases the grip portion outward away from the tubular ends of the frame. A dampening mechanism is provided to retard the return of the grips to their original position after they have telescoped inward after impacting with the user. A hydraulic dampening system employing grease and an pneumatic system employing air are described.

Description:
This application claims the benefit of provisional application No. 60/156,758, filed Sep. 29, 1999. 

   BACKGROUND OF THE INVENTION 
   Impact with a handlebar in slow speed bicycling crashes has been identified as a mechanism for causing life threatening truncal injuries in children. Severe abdominal injury is seldom immediately evident following bicycle trauma related accidents. A consequential injury that may result from such a handlebar accident is a traumatic abdominal wall hernia (TAWH). A TAWH is produced by a direct blow that is either blunt or may impact the skin with an insufficient force to puncture the skin. A TAWH occurs because the elasticity of the skin is greater than the other layers of the abdominal wall. The skin remains intact despite the fact that there may be significant disruption below the abdominal wall, i.e. muscle and fascia, thus causing a difficulty in detection. In the worst case scenario, bicycle handlebar trauma can cause death. Bicycle handlebar trauma is often hard to detect initially in a clinical atmosphere and may be further complicated by delayed injury. 
   In recent years, an increasing number of children have suffered severe abdominal trauma while riding their bicycles. Since this mechanism of injury has not been well described and abdominal trauma is difficult to detect without a thorough examination, many children are sent home and forced to return to the hospital when the symptoms become more severe. One particular form of accident is responsible for the majority of these injuries. This involves a rapid shift in momentum caused by the front tire of the bicycle coming into contact with a changing interface such as the transition from sidewalk to grass. This transition stops the bicycle and tends to rotate the front wheel and handlebars. The rider continues to move forward into an end of the handlebar and often hits the ground with the handlebar end still in contact with his/her abdomen. On impact, an additional blow is exerted by the handlebar on the rider, which is translated into the rider&#39;s abdominal area. 
   It would be beneficial to develop a handlebar which absorbs at least some of the energy generated by the impact of the rider with the handlebar, thereby reducing the amount of force transmitted to the rider as a result of the impact. 
   BRIEF SUMMARY OF THE INVENTION 
   A safety handlebar comprising a frame having opposing, tubular outer ends, a shaft having first and second shaft ends, the first shaft end slidably being connected with one of the tubular out ends; a bias member operatively associated with the shaft and the frame so as to bias the second shaft end away from the frame; and a dampener operatively associated with the first shaft end and the frame so as to dampen displacement of the second end of the shaft away from the frame. 
   A child-safe handlebar comprising a generally tubular frame having a tubular outer end; a shaft having opposing first and second ends, the first shaft end being slidably telescoped with the fame outer end; and a fluid dampener operatively associated with the frame and the shaft at the outer end to slow movement of the shaft out of the outer end. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
       FIG. 1  is a front view of a handlebar in accordance with the present invention; 
       FIG. 2  is a front view of the handlebar mounted onto a bicycle; 
       FIG. 3  is a cross-sectional view of an end of the handlebar in an uncompressed condition according to a first embodiment of the present invention; 
       FIG. 4  is a cross-sectional view of the end of the handlebar in a compressed condition according to a first embodiment of the present invention; and 
       FIG. 5  is a cross-sectional view of an end of the handlebar in an uncompressed condition according to a second embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Certain terminology is used in the following description for convenience only and is not limiting. The words “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the handlebar and designated parts thereof. The words “inboard” and “outboard” refer to sides of elements proximate to and distal from, respectively, the geometric center of the handlebar and designated parts thereof. In  FIGS. 3 ,  4  and  5 , “inboard” refers to a direction toward the left-hand side of the figures, and “outboard” refers to a direction toward the right-hand side of the figures. The words “left” and “right”, as used herein, correspond to sides of the handlebar as viewed by a rider on a bicycle. The word “a” is defined to mean “at least one”. The terminology includes the words above specifically mentioned, derivatives thereof and words of similar import. In the drawings, like numerals are used to indicate like elements throughout. 
   Referring now to  FIGS. 1 and 2 , the present invention is a child-safe handlebar  10  for use on a BMX style bicycle  12 . Although the handlebar  10  will be discussed in relation to its use on a BMX bicycle, those skilled in the art will realize the present invention can also be used with handle bars of other styles for other types of bicycles, including but not limited to a single, continuous bent tube, and other forms of personal transportation and toys that are pushed or ridden. 
   The handlebar  10  is provided by a generally tubular frame  21 , which includes at least left and right tubular sides L and R, respectively, which extend from a generally horizontal connector bar  14 . The connector bar  14  is connected to a generally vertical pivot post or “stem”  16  on the bicycle  12 , which defines an axis about which the handlebar  10  rotates. The pivot post  16  is connected to the fork  17  supporting a front wheel  18  on the bicycle  12  such that, when a rider (not shown) turns the handlebar  10  and rotates the pivot post  16 , the front wheel  18  turns with the handlebar  10 , allowing the rider to steer the bicycle  12 . The BMX style handlebar  10  can further include a stabilizer bar  20  which connects the left and right tubular sides L, R together at a location above the connector bar  14 . The stabilizer bar  20  can be padded (not shown) as is well known in the art. The stabilizer bar  20  is not part of the present invention and will not be further described herein. 
   The left and right tubular sides or arms L, R of the handlebar  10  are preferably mirror images of each other, and only the right side R of the handlebar  10  will be described, although the present description will pertain to the left side L of the handlebar  10  as well. The handlebar frame  21  is preferably constructed to steel, although those skilled in the art will realize that the handlebar frame  21  can be other materials and cross-sectional shapes as well. 
   A first, inboard end  22  of the right tubular side R of the handlebar frame  21  is fixedly attached to the connector bar  14 . An outboard or distal end  24  of the right side R of the handlebar frame  21  is tubular and extends away from the connector bar  14 , generally at an elevated angle and generally toward the rear of the bicycle  12 , as shown in FIG.  2  and also forms an outer or distal end of the frame  21 . 
   As shown in cross-section in  FIGS. 3 and 4 , a tubular shaft  26  is telescopically coupled with, preferably received in and extending outwardly from, the outer end  24  of the handlebar frame  21 , The shaft  26  includes a first inner end  30 , which is generally slidably disposed within the outer end  24  of the handlebar frame  21 . Shaft  26  is thus slidably connected with the frame  21  The shaft  26  also includes a second outer or distal end  32  which generally extends outwardly from the outer end  24  of the handlebar frame  21 . Preferably, when in an uncompressed state, the shaft  26  extends outwardly from the outer end  24  of the handlebar frame  21  approximately three and a half (3½) inches, although those skilled in the art will realize that the shaft  26  can extend more or less than three and a half inches from the outer end  24  of the arm R of frame  21  as desired or necessary. 
   A biasing member, preferably in the form of a helical spring  34 , is operatively associated with the shaft  26  and the frame  21  so as to bias the second outer shaft end  32  away from the outer end  24  of the frame  21 . Preferably, spring  34  coils around the exterior of the shaft  26  such that a first, inboard end  36  of the spring  34  engages the second end  24  of the handlebar frame  21 . The spring  34  is normally in an uncompressed state, although those skilled in the art will realize that the spring  34  can be at least partially compressed in a normal state. The shaft  26  generally serves as a support for the spring  34 . Preferably, a spring  34  with a k value of 10 lb/in is used, although those skilled in the art will realize that springs with other k values can be used. Also, preferably, the spring  34  is approximately three (3) inches long when in an uncompressed state, although those skilled in the art will realize that the spring  34  can be longer or shorter than three inches when in an uncompressed state. 
   A cover  40  extends over the spring  34  and the portion of the shaft  26  which is located outboard of the outer end  24  of the handlebar frame  21 , as well as a portion of the outer end  24 . The cover  40  preferably is slidably disposable over the outer end  24  of the handlebar frame  21  as will be discussed in more detail herein. A first, inboard end  42  of the cover  40  includes an annular wall  44  which is slidable along the exterior of the second end  24  of the handlebar frame  21 . 
   A second, outboard end  46  of the cover  40 , distal from the handlebar frame  21 , is preferably closed and is fixedly connected to the second end  32  of the shaft  26 . A second end  48  of the spring  34  engages the second end  46  of the cover  40 , (or of the shaft) biasing the second end  32  of the shaft  26  away from the second end  24  of the handlebar frame  21 . The second end  46  of the cover  40  also includes a compressible cap  50  extending outwardly therefrom. Preferably, the cap  50  is constructed of rubber or foam, although those skilled in the art will realize that any compressible material can be used. The cap  50  provides a soft, cushioned surface to distribute an impact force more evenly to the closed end  46  of the cover  40 . 
   Handlebar  10  further includes a dampener operatively associated with at least one of the shaft and the frame so as to slow displacement of the second end of the shaft away from the frame outer end  24 . Preferably, the cover  40  encloses first and second generally annular chambers  52 ,  54 , respectively, which are in fluid contact with each other and defined by the cover  40 , outer end  25  and shaft  26 . A dampening fluid, preferably a dampening grease  56 , is provided in the first chamber  52 , surrounding the spring  34 . Preferably, the dampening grease  56  has a dynamic viscosity of between about 60 and 130 and, more particularly, between 65 and 128.5 N/s-m 2 . (Dynamic viscosity of a fluid is equal to kinematic viscosity times density of the fluid.) NyoGel 774VL, manufactured by Nye Lubricants in Hockessin, Delaware, which falls within the preferred range, has been used as the dampening grease  56 , although those skilled in the art will realize that other lubricants, including other greases or fluids, can be used. The dampening grease  56  provides a dampening effect similar to the hydraulic oil used in automobile shock absorbers. The first chamber  52  is separated from a second chamber  54  by a generally annular wall  58  which extends radially outwardly from the second end  24  of the handlebar frame  21  but is slidably engaged with the interior of the cover  40 . Two or more one-way valves  60 ,  64  are provided. Preferably, first one-way valve  60  with a relatively larger opening allows the dampening grease  56  to be transferred from the first chamber  52  to the second chamber  54 . Preferably, second one-way valve  64  with a relatively smaller opening allows the dampening grease  56  to be transferred from the second chamber  54  to the first chamber  52  more slowly than the transfer of the grease  56  through first valve  60 . Preferably, the second chamber  54  is also filled with dampening grease  56  to avoid forming any air pockets that could adversely affect the operation of the dampening system. Although larger and smaller individual valves are described, it will be appreciated that greater numbers of smaller valves can be provided to pass dampening grease from the first to the second chambers. Valves  60 ,  64  can be of any construction. Flap or slit valves are suggested. 
   An O-ring  66  or other seal known to those skilled in the art preferably is fixedly attached to the annular wall  44  at an interface between the annular wall  44  and the second end  24  of the handlebar frame  21  to prevent dampening grease  56  from leaking out of the second chamber  54  and onto the outer surface of the handlebar frame  21 . 
   Normally, the spring  34  is in an uncompressed state or alternately, in a partially compressed state, as shown in FIG.  3 . When the bicycle  12  encounters an obstacle (not shown) that causes the bicycle  12  to suddenly stop, the front wheel  18  of the bicycle  12  tends to turn and the rider is thrown into one of the two distal ends of the handlebar  10  rotated with the wheel  18  toward the rider (e.g., the outer end  24  of the frame  21 ). The rider&#39;s body contacts the cap  50  and the second end  46  of the cover  40 , forcing the shaft  26  into the handlebar frame  21 , generally with an axial impacting force. The rider can additionally fall on that handlebar end if the rider and bike continue to fall over together. The cap  50  compresses and slows and distributes the impact force throughout the second end  46  of the cover  40 . The cover  40  and the shaft  26  then axially translate inward along the outer end  24  of the handlebar frame  21  (to the left in  FIGS. 3 and 4 ) at a rate and distance which is proportional to the magnitude of the impact force. The second end  48  of the spring  34  is compressed toward the first end  36  of the spring. The spring  34  resists the impact force and gradually slows down the rider as the rider compresses the spring  34 , absorbing a portion of the energy of impact. 
   As the cover  40  is inwardly translated, the first chamber  52  is compressed and the second chamber  54  is expanded, forcing the dampening grease  56  from the first chamber  52 , through the first one-way valve  60 , and into the second chamber  54 . The second one-way valve  64  is closed at this time. Due to the relatively large size of the first one-way valve  60 , the transfer of the dampening grease  56  from the first chamber  52  to the second chamber  54  does not significantly affect the compression rate or distance of the spring  34 . 
   Upon compression, the spring  34  stores a portion of the energy of impact. This energy is released upon release of the force from the second end  46  of the cover  40 . The energy stored in the spring  34  during compression acts to extend the spring  34  toward its initial, preferably uncompressed condition and return the shaft  26  and cover  40  to their initial positions. As the spring  34  expands, the second chamber  54  is compressed and the first chamber  52  is expanded, forcing the dampening grease  56  through the second one-way valve  64 . The first one-way valve  60  is closed at this time. However, since the second one-way valve  64  is relatively small compared to the first one-way valve  60 , the dampening grease  56  does not flow as swiftly from the second chamber  54  into the first chamber  52  as the dampening grease  56  flowed from the first chamber  52  into the second chamber  54 , thus dampening the return speed of the spring  34  and preventing the second end  46  of the cover  40  from springing back into the rider and causing additional harm to the rider. 
   In a second embodiment handlebar  110 , one outer end  124  of which is shown in cross-section in  FIG. 5 , the dampening grease  56  and first and second valves  60 ,  64  are eliminated and an air flow dampener is employed, preferably a feather washer  156 . Feather washer  156  is a generally resilient or elastic cup-shaped member with a feathered outer edge and is used in hydraulic and/or pneumatic systems as a combined valve and seal. The feather washer  156  is preferably located on the first (inner) end  130  of a shaft  126 , which is slidably received in the tubular distal or outer end  124  of handlebar frame  121 , as shown in FIG.  5 . The use of a feather washer  156  in a tube should be well known to those skilled in the art. The washer  156  is oriented to allow air to easily pass by the outside of the washer  156  when the feather washer  156  and the shaft  126  are forced inwardly (during compression), but to “flap out” as air is attempts to pass by the feather washer  156  when the compressed spring  134  moves the cover  140  and washer  156  outwardly from outer end  124  (during spring expansion). Another seal  160  is preferably provided around the distal end  124  of frame  121  to form a seal for chamber  152  within cover  140 . This chamber  152  reduces in volume as the distal end  146  of cover  140  moves inward over the distal end  124  of handlebar frame  121 . Seal  160  is at least partially retained in position by a generally radially outwardly projecting wall  170  over which an inner cylindrical surface of cover  140  slides as it telescopes on frame end  124 . Chamber  152  is defined by the line surface of cover  140 , seal  160  and wall  170 . 
   The second embodiment shows an alternative compressible cap  150  to the cap  50  of the first embodiment. The alternative cap  150  is preferably a foam ball which is mounted to the exterior of the outer or distal end  146  of the cover  140  by being slipped over and adhered to a stem  151 . The foam ball constituting cap  150  provides a larger surface area of an elastic material which is exposed to the rider on impact. However, those skilled in the art will realize that either cap  50 ,  150  or any similar resilient or elastic endpiece can be used in either the first or second embodiments, or the endpiece can be of the known type and need not be elastic. They would also realize that stem  151  could be eliminated and the cap  150  held to the outer end  146  of cover  140  by a fastener through the ball and into the end of cover  140 . 
   In operation, when struck by the rider, the shaft  126  and the cover  140  are inwardly translated along the outer or distal end  124  of the handlebar and the spring  134  is compressed as a result of the impact force upon the outer or distal end  146  of the cover  140 , air in the chamber  152  passes by the feather washer  156  and into the frame  121  without significantly affecting the compression rate of the spring  134 . 
   After the impact force is released from the second (outer) end  146  of the cover  140 , the spring  134  expands, forcing the shaft  126  back toward its pre-impact position. However, the feather washer  156  “flaps out”, creating resistance to air flow within the shaft  126  and the handlebar frame  121 , slowing down the return speed of the spring  134  and the shaft  126 , and preventing the outer or distal end  146  of the cover  140  from springing back into the rider and causing additional harm to the rider. 
     FIG. 5  shows the outer or distal end  146  of the cover  140  being a separate piece screw threaded into a threaded end of a cylindrical portion  140   a  of the cover  140 . This feature, as are several other features shown, is for assembly purposes only and those skilled in the art will realize that other methods of connecting the second end  146  of the cover  140  to the second end  124  of handlebar  110 . For example, the second frame end  124  might be provided by a separate tubular member which is coupled by a threaded or compression collar  164  (in phantom) or otherwise fixedly joined to the distal end of the left and right arms L, R, for example, by fasteners or welds (not depicted). 
   Use of the handlebar  10 ,  110  results in approximately a 50% reduction of impact force transmitted to a rider as compared to a standard bicycle handlebar in collisions described above. 
   Although two preferred methods of dampening the return action of the handlebar  10 ,  110  are shown, those skilled in the art will realize that other methods of dampening can be used without departing from the spirit and scope of the present invention. 
   Applicants&#39; provisional patent application Ser. No. 60/156,758 is incorporated by reference herein in its entirety including all appendices. 
   It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof it is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.