Abstract:
A split cylindrical clamp encloses inner ends of grip bars of a folding handlebar to hold the grip bars in a firm, stationary, and strong riding position. A single user gesture flips a clamp lever to loosen the split cylindrical clamp allows the grip bars to be slid outward and folded to a folded position. The split cylindrical clamp is then tightened with another single gesture, flipping the clamp lever in an opposite direction, locking the grip bars in the folded position. While locked in the folded position, the grip bars are entirely immobilized.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to folding handlebars and, in particular, to a folding handlebar which is particularly strong while simultaneously minimizes wear on parts.  
         BACKGROUND OF THE INVENTION  
         [0002]    In recent decades, popularity of folding bicycles has grown significantly as populations increase in density and reliance on public transportation. Public transportation often fails to deliver commuters precisely to their respective destinations. Accordingly, most people using public transportation must resort to walking for a relatively small, yet significant, distance. Bicycles tend to be unsatisfactory adjuncts to public transportation since bicycles are relatively large and bulky items which cannot be easily carried on public transportation such as buses and trains.  
           [0003]    One substantially successful transportation mechanism for bridging the gaps in public transportation for individual commuters is the folding bicycle. Currently available folding bicycles can fold to sizes smaller than a typical small suitcase and yet ride nearly as easily as a regular bicycle. To achieve such small sizes, folding bicycles typically involve intricate and complex mechanical solutions. One area in which substantial attention in devoted is that of the handlebars.  
           [0004]    Most folding bicycles either use a folding handlebar stem or require that the front wheel and tire be removed for complete folding. Removing the front wheel of a bicycle can be awkward, especially for a commuter, since the removed wheel is a detached piece of equipment that must either (a) somehow be attached to the rest of the folded bicycle or (b) be carried separately. Designing the handlebar to be foldable introduces weakness and perhaps unwanted play and movement in a critical structural part of a bicycle.  
           [0005]    Folding handlebars date back to the early history of the bicycle and yet tend not to be used in folding bicycles. Early attempts at folding handlebars were to allow for adjustable riding positions. Examples include folding handlebars described by U.S. Pat. No. 864,202 to Simmons (Aug. 27, 1907); U.S. Pat. No. 3,863,521 to Gatsos et al. (Feb. 4, 1975); and U.S. Pat. No. 5,737,967 to Hartley (Apr. 14, 1998). These folding handlebars focus on adjustability while riding and provide little, if any, reduction in size.  
           [0006]    On the other hand, folding handlebars which are designed to reduce the size of a bicycle or other vehicle for storage and/or carrying typically rely on mechanisms external to the handlebars and/or introduce weakness and movement in a critical structural component of the vehicle. Mechanisms external to the handlebars (e.g., U.S. Pat. No. 4,634,138 to Fryer et al.—Jan. 6, 1987) such as external spring latch handles pose risks for snagging clothing while riding.  
           [0007]    More important, however, is the introduction of weakness and movement into a critical structural component of a bicycle. Handlebars of a bicycle bear heavy loads. In particular, more aggressive contemporary riding styles, e.g., in urban and off-road riding, place a rider&#39;s weight more forward with substantial weight over the handlebars. In addition, any bumps or shocks at the front wheel are typically translated directly to the handlebars. While other front-end components are positioned to handle substantial vertical loads of shocks and bumps to the front tire, handlebars literally stand out as the component to handle such loads transversely. Accordingly, handlebars are a structurally critical component of a bicycle, and they must handle transverse loading.  
           [0008]    Most conventional folding handlebars introduce a folding mechanism which allows for folding in precisely the transverse direction in which loads are borne. One example is described in British Patent No. 7578 (1891) to Parkes et al. in which handlebars slide out of a tube to expose a joint about which the handlebars fold. In sliding in and out of a tube, the handlebars require a clearance, however small, to allow for such sliding. Such a clearance, however small, introduces play in the handlebars such that the handlebars are capable of movement independent of the remainder of the bicycle and independent of the sliding motion required to fold the handlebars. In particular, such introduces play transverse to the handlebars. Such play, during rugged riding, can cause excessive wear in the handlebars, can cause weakness in the handlebars, and can be annoying to the rider.  
           [0009]    What is needed is a folding handlebar, e.g., one suitable for use on a bicycle, which allows virtually no play transverse to the handlebar and which handles transverse loading virtually as well as a conventional, non-folding handlebar.  
         SUMMARY OF THE INVENTION  
         [0010]    In accordance with the present invention, a split cylindrical clamp encloses inner ends of grip bars of a folding handlebar to hold the grip bars in a firm, stationary, and strong riding position. While riding a bicycle in which such folding handlebars are installed, no difference in riding feel of the handlebars is noticed and no play or movement in the respective parts is permitted due to the strength of the split cylindrical clamp.  
           [0011]    A single user gesture flips a clamp lever to loosen the split cylindrical clamp allows the grip bars to be slid outward and folded to a folded position. The split cylindrical clamp is then tightened with another single gesture, flipping the clamp lever in an opposite direction, locking the grip bars in the folded position. While locked in the folded position, the grip bars are entirely immobilized, thereby resisting damage to the handlebar and any attached cables and levers during shipping or storage.  
           [0012]    Due to the leverage available in an eccentric clamp used to tighten the split cylindrical clamp and the resulting great force, only a small inner portion of the grip bars is placed inside the split cylindrical clamp in the riding position. In addition, the grip ends fold behind the split cylindrical clamp to remain inside the split cylindrical clamp for clamping in the folded position. Accordingly, the folding handlebar is generally no wider than the split cylindrical clamp when folded - an extremely narrow folded handlebar.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIGS. 1 and 2 are perspective exploded views of a folding handlebar in accordance with the present invention.  
         [0014]    [0014]FIG. 3 is a perspective view of the handlebar of FIGS. 1 and 2 in a riding position.  
         [0015]    [0015]FIG. 4 is a perspective view of the handlebar of FIGS. 1 and 2 in a folded position.  
         [0016]    [0016]FIGS. 5 and 6 illustrate transition of the folding handlebar of FIGS. 1-4 from the riding position to the folded position.  
         [0017]    [0017]FIGS. 7-9 illustrate transition of the folding handlebar of FIGS. 1-4 from the folded position to the riding position.  
         [0018]    [0018]FIGS. 10-12 are cross-section views of the folding handlebar of FIGS. 1-2 showing design details.  
         [0019]    [0019]FIG. 13 is a perspective view of a socket of the split cylindrical clamp of the folding handlebar of FIGS. 1-2.  
         [0020]    [0020]FIG. 14 is a bottom plan view of the socket of FIG. 13.  
         [0021]    [0021]FIG. 15 is a top plan view of the socket of FIG. 13 .  
         [0022]    [0022]FIG. 16 is a cross-section view taken at line E-E (FIG. 15) of the socket of FIG. 13.  
         [0023]    [0023]FIG. 17 is a cross-section view taken at line F-F (FIG. 15) of the socket of FIG. 13.  
         [0024]    [0024]FIG. 18 is a cross-section view taken at line G-G (FIG. 15) of the socket of FIG. 13.  
         [0025]    [0025]FIG. 19 is a cross-section view taken at line H-H (FIG. 15) of the socket of FIG. 13.  
         [0026]    [0026]FIG. 20 is a cross-section view taken at line I-I (FIG. 15) of the socket of FIG. 13.  
         [0027]    [0027]FIG. 21 is a perspective view of a clamp of the split cylindrical clamp of the folding handlebar of FIGS. 1-2.  
         [0028]    [0028]FIG. 22 is a bottom plan view of the clamp of FIG. 21.  
         [0029]    [0029]FIG. 23 is a cross-section view taken at line E-E of the clamp of FIG. 22.  
         [0030]    [0030]FIG. 24 is a cross-section view taken at line F-F of the clamp of FIG. 22.  
         [0031]    [0031]FIG. 25 is a cross-section view taken at line G-G of the clamp of FIG. 22.  
         [0032]    [0032]FIG. 26 is a cross-section view taken at line I-I of the clamp of FIG. 22.  
         [0033]    [0033]FIG. 27 is a top plan view of a socket of an alternative embodiment of the split cylindrical clamp of the folding handlebar of FIGS. 1-2. 
     
    
     DETAILED DESCRIPTION  
       [0034]    In accordance with the present invention, two grip ends  104  (FIG. 1) of a folding handlebar  100  are firmly held in either a riding position (FIG. 3) or in a folded position (FIG. 4) by a quick-release clamp which includes a clamp  108  (FIG. 1) and a socket  106 . In the riding position, clamp  108  and socket  106  firmly and securely hold grip ends  104  in place with no free play and therefore no resulting wear between grip ends  104 , clamp  108 , and socket  106 . More importantly, a rider&#39;s control of a bicycle in which folding handlebar  100  is installed is greatly improved by the absolute elimination of play in the various parts of folding handlebar  100 . In addition, complete immobilization of grip ends  104  in the folded position (FIG. 4) by clamp  108  and socket  106  prevents damage to grip ends  104  and any brake and/or shift cables and/or levers during transport, e.g., as checked baggage with an airline.  
         [0035]    Socket  106  (FIG. 1) is fixed to a stem  102 , by adhesive, welding, or press-fit. Stem  102  is in turn fixed to a bicycle or other vehicle controllable by handlebars. Clamp  108  is attached to socket  106  by a hinge pin  116 , about which clamp  108  can rotate relative to socket  106 . A clamp screw  112  passes through clamp  108  and screws into socket  106 . Clamp screw  112  also passes through a clamp pivot  114  and a clamp lever  110 . A user tightens and loosens the clamp of socket  106 , hinge pin  116 , and clamp  108  by moving clamp lever  110  quickly and without tools. This process is described in greater detail below.  
         [0036]    Each grip end  104  includes a inside guide pin  118  and an outside guide pin  120 , both of which protrude entirely through grip ends  104 . Inside guide pins  118  remain within the clamp of socket  106 , hinge pin  116 , and clamp  108  while outside guide pins  120  are inside that clamp in the riding position as shown in FIG. 3 and are outside that clamp in the folded position as shown in FIG. 4.  
         [0037]    [0037]FIG. 2 shows folding handlebar  100  from a slightly different perspective.  
         [0038]    [0038]FIGS. 5 and 6 illustrate the folding of handlebar  100  from the riding position to the folded position. In step  1  (FIG. 5), the user moves clamp lever  110  forward to loosen clamp  108  from socket  106 . Clamp lever  110  is an eccentric clamp. Eccentric clamps are known and are not described further herein. Loosening of clamp  108  from socket  106  releases pressure placed upon grip ends  104  by clamp  108  and socket  106 , allowing movement of grip ends  104  between clamp  108  and socket  106 .  
         [0039]    In step  2 , the user slides grip ends  104  outward, away from the center of socket  106 . Outside guide pins  120  slide out of outside guides  502 , allowing grip ends  104  to pivot about inside guide pins  118  which remain contained within the clamp of socket  106  and clamp  108 . In step  3 , the user pivots grip ends  104  about concealed inside guide pins  118  until grip ends  104  are positioned within respective retention recesses  506 - 508  (FIG. 6).  
         [0040]    Retention recesses  506 - 508  are generally the size and shape of the outer cross-sectional shape of grip ends  104 , e.g., circular and having a diameter of 2.2 cm in this illustrative embodiment. Each retention recess  506 - 508  has a socket recess  506  on socket  106  and a clamp recess  508  on clamp  108 . In step  4 , the user moves clamp lever  110  back to move clamp  108  toward socket  106  to thereby clamp grip ends  104  within respective retention recesses  506 - 508 . As a result, grip ends  104  are firmly immobilized and secured.  
         [0041]    The transition from the folded position to the riding position is merely the reverse of these steps as illustrated in FIGS. 7-9. In step  1  (FIG. 7), the user moves clamp lever  110  forward, loosening retention recesses  506 - 508  to free grip ends  104 . In step  2  (FIG. 8), the user moves grip ends  104  from the folded position to the riding position and, in step  3 , slides grip ends  104  into a cylindrical recess between socket  106  and clamp  108 . In sliding grip ends  104  in step  3 , outside guide pins  120  slide into guides  502 . In step  4  (FIG. 9), the user moves clamp lever  110  back to tighten socket  106  and clamp  108  about grip ends  104  to hold them securely for carefree riding as if grips ends  104  were a single, integral handlebar.  
         [0042]    [0042]FIG. 13 shows socket  106  in a perspective view. In addition to outside guides  502 , socket  106  includes insides guides  1308  in which inside guide pins  118  (FIG. 1) are positioned and within which guide pins  118  slide. Socket  106  (FIG. 13) also includes holes  1304  for hinge pin  116  (FIG. 1) and a drilled and tapped hole  1306  into which clamp screw  112  is screwed.  
         [0043]    [0043]FIG. 14 is a bottom plan view of socket  106 . FIG. 15 is a top plan view of socket  106 . FIG. 16 is a cross-section view taken at line E-E (FIG. 15). FIG. 17 is a cross-section view taken at line F-F (FIG. 15). FIG. 18 is a cross-section view taken at line G-G (FIG. 15). FIG. 19 is a cross-section view taken at line H-H. FIG. 20 is a cross-section view taken at line I-I.  
         [0044]    [0044]FIG. 22 shows clamp  108  in a perspective view. In addition to outside guides.  502 , clamp  108  includes insides guides  2108  in which inside guide pins  118  (FIG. 1) are positioned and within which guide pins  118  slide. Clamp  108  (FIG. 21) also includes holes  2102  for hinge pin  116  (FIG. 1) and a drilled hole  2106  (FIG. 21) through which clamp screw  112  (FIG. 1) moves freely.  
         [0045]    [0045]FIG. 22 is a bottom plan view of clamp  108  . FIG. 23 is a cross-section view of clamp  108  taken at line E-E (FIG. 22). FIG. 24 is a cross-section view of clamp  108  taken at line F-F (FIG. 22). FIG. 25 is a cross-section view of clamp  108  taken at line G-G (FIG. 22). FIG. 26 is a cross-section view of clamp  108  taken at line I-I (FIG. 22).  
         [0046]    [0046]FIGS. 10 and 11 are cross-section views of folding handlebar  100  illustrating a few details. In this illustrative embodiment, holes  2102  of clamp  108  are open such that clamp  108  can easily be removed without removing hinge pin  116 —either for assembly or for maintenance. In addition, the upper inner portions of socket  106  and clamp  108  are rounded off to form a crescent-shaped gap  1002  in the vicinity of hinge pin  116  between grip end  104  and the hinge formed of hinge pin  116 , socket  106 , and clamp  108 . Crescent-shaped gap  1002  allows clamp  108  to rotate about hinge pin  116  relative to socket  106  without interference by grip end  104 . Crescent-shaped gap  1002  is positioned such that substantially less than 50% of the outer perimeter of grip end  104  is precisely fit by either socket  106  or clamp  108 . Accordingly, neither socket  106  nor clamp  108  grips grip end  104  when clamp  108  is loosened.  
         [0047]    For similar reasons, inside guides  1308  and  2108  (FIG. 10) do not tightly fit inside guide pins  118  but are instead widened by an angle of four (4) degrees as shown in FIGS. 17 and 24. Accordingly, enough play is permitted to enable rotation of clamp  108  (FIGS. 10 and 11) about hinge pin  116  relative to socket  106  without interference by grip end  104 .  
         [0048]    [0048]FIG. 12 is another cross-section view of folding handlebar  100  illustrating additional detail. FIG. 12 shows grip end  104  in the folded position. A portion  1202  of grip end  104  extends beyond inside guide pin  118 . To permit rotation of grip end  104  about inside guide pin  118 , socket  106  and clamp  108  have respective recesses  1310  and  2110  to accommodate portion  1202  throughout rotation of grip end  104  and with grip end  104  in the folded position.  
         [0049]    [0049]FIG. 27 shows an alternative embodiment of socket  106  as socket  106 B. A tapped hole  2706  and retention recesses  2710  are analogous to tapped hole  1306  (FIG. 13) and retention recesses  506  (FIG. 5), respectively. However, outside guides  502  of socket  106  are replaced with outside guides  2702  (FIG. 27) of socket  106 B. Outside guides  2702  are generally circular with an opening smaller than the diameter of outside guides  2702 . Outside guide pins  118  (FIG. 1) of grip ends  104  are replaced in this alternative embodiment with spring loaded, rounded or tapered push buttons which can only be removed from outside guides  2702  (FIG. 27) when pressed by the user. Accordingly, inadvertent loosening of clamp lever  110  (FIG. 1) is insufficient to permit accidental sliding of grip ends  104  outward and resulting accidental folding of grip ends  104  during riding of a bicycle on which folding handlebar  100  is installed.  
         [0050]    In another alternative embodiment, an elastic cord is stretched between respective inside guide pins  118  of grip ends  104  to resist inadvertent extraction as shown in step  2  of FIG. 5 and to assist insertion as shown in step  3  of FIG. 9. Some embodiments include both push-button outside guide pins as described with respect to FIG. 27 and the elastic cord described immediately above.  
         [0051]    In the illustrative embodiment shown in the figures, all shown measurements are in millimeters and all tolerances, unless otherwise shown in the figures, are ±0.5 mm for measurements rounded to the nearest millimeter, ±0.2 mm for measurements shown to one decimal place, ±0.1 mm for measurements shown to two decimal places, and ±0.25 degrees for angles. Sockets  106  and  106 B and clamp  108  are made of forged aluminum  7005  with a minimum yield strength of 170 MPa.  
         [0052]    The above description is illustrative only and is not limiting. Therefore, the present invention is defined solely by the claims which follow and their full range of equivalents.