Abstract:
A portable bicycle comprises a front bar having a front end coupled to a head tube, a rear frame section including a lower seat tube extended upwardly from a bottom bracket, a upper seat tube spaced and aligned with the lower seat tube, and a hollow rear bar for slidably receiving the front bar, the rear bar being intersected the upper and lower seat tubes, and a fastening mechanism for securing the front bar to the rear bar. Detaching a seat post and a saddle, unfastening the fastening mechanism, fully projecting the front bar from a rear opening of the rear bar, and fastening the fastening mechanism will shorten the distance between front and rear wheels to a minimum and facilitate the bicycle to store or carry in a much reduced size.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to stretching bicycles and more particularly to a portable bicycle having a compact size after disassembly so as to save storage space while being carried.  
           [0003]    2. Description of the Prior Art  
           [0004]    Conventionally, a stretching bicycle has a separable crossbar consisting of a front bar and a rear bar releasably secured to the front bar by a fastening mechanism. Thus, the maximum length reduction of the bicycle is defined by the front and rear bars, the head tube, and the seat tube.  
           [0005]    The present inventor had filed an application in the United States of America as patent application Ser. No. 10/346,128 on Jan. 17, 2003 (hereinafter prior art) which is incorporated herein by reference. Prior art discloses a stretching bicycle characterized as follows. Two parallel main seat tube and auxiliary seat tube are extended upwardly from the bottom bracket in a slightly inclined direction. Also, the main seat tube is laterally displaced a predetermined distance from a lengthwise direction of the bicycle (i.e., not aligned with the crossbar). A seat stay is extended rearwardly from both the main seat tube and the auxiliary seat tube to the rear wheel. A seat post is slidably inserted into the main seat tube. A laterally extended bar is interconnected the seat post and a saddle such that the saddle is adapted to align with the lengthwise direction of the bicycle again (i.e., aligned with the crossbar). The lower portion of the auxiliary seat tube is coupled to a reinforcement tube and a top thereof is coupled to a crossbar having both ends open. Two T-shaped gaps are formed adjacent a front end and a rear end of the crossbar respectively for providing flexibility thereto. A sliding tube has a front end fixedly coupled to head tube and a rear end adapted to insert through the crossbar. Also, a lengthwise first groove and a lengthwise mated second groove are formed on the crossbar and the sliding tube respectively for facilitating a correct coupling of the crossbar and the sliding tube and preventing both from turning each other. Two quick releases are adapted to clamp around the gaps for securing the sliding tube to the crossbar. Prior art has advantages of being structurally strong and making a maximum length reduction of the bicycle achievable. However, prior art still has the disadvantage of having a relatively heavy frame due to the provision of the main seat tube, the auxiliary seat tube, and the laterally extended bar. Moreover, the saddle and the seat post are not aligned vertically. Hence, the weight of the driver may not totally transmit to other components of the frame via the saddle, the laterally extended bar, and seat post. In other words, the joining portion of the laterally extended bar and the seat post bears a great portion of the weight of the driver. This in turn has the potential of breaking the joining portion while driving. This is dangerous. Thus, it is desirable to provide a portable bicycle having a compact size after disassembly in order to overcome the above drawbacks of the prior art.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to provide a portable bicycle which is adapted to decrease its length to a minimum by projecting a front bar from the rear opening of a rear bar to a maximum extent.  
           [0007]    It is another object of the present invention to provide a portable bicycle which is adapted to decrease it length without the provision of a seat tube composed of a plurality of components such that the present invention has the advantages of eliminating the provision of an offset seat tube, being lightweight, being highly portable, being easy in manufacture, and eliminating the need of aligning the center line of a saddle again.  
           [0008]    For achieving the above objects, there is provided a portable bicycle comprising a front frame section including a head tube, a fork, a handlebar, a stem interconnected the handlebar and the head tube, a front wheel, and a front bar having a front end coupled to the head tube; a rear frame section including a bottom bracket, a pair of pedals coupled to the bottom bracket, a sprocket wheel coupled to the bottom bracket, a rear wheel, a chain stay extended rearward from the bottom bracket to an axle of the rear wheel, a seat stay having a rear end coupled to the axle of the rear wheel, a lower seat tube extended upwardly from the bottom bracket, an upper seat tube aligned with the lower seat tube, a seat post slidably inserted into the upper and lower seat tubes, a saddle formed on a top of the seat post, and a hollow rear bar for slidably receiving the front bar, the rear bar being intersected the upper and lower seat tubes and having a top aperture and a bottom aperture with the upper and lower seat tubes connected thereat; and at least one fastening mechanism for securing the front bar to the rear bar; whereby detaching both the seat post and the saddle, unfastening the fastening mechanism, and sliding the front bar with respect to the rear bar to a limit will collapse the bicycle to a compact size. In response to projecting the front bar from the rear opening of the rear bar to dispose above the rear wheel, the bicycle has a minimum length and is able to save storage space while being stored or carried. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The drawings disclose an illustrative embodiment of the present invention which serves to exemplify the various advantages and objects hereof, and are as follow:  
         [0010]    [0010]FIG. 1 is an exploded perspective view of a first preferred embodiment of portable bicycle according to the invention;  
         [0011]    [0011]FIG. 2 is a perspective view of the assembled bicycle of FIG. 1;  
         [0012]    [0012]FIG. 3 is a side plan view of the bicycle of FIG. 2;  
         [0013]    [0013]FIGS. 4 and 5 are cross-sectional views taken along line  4 - 4  and line  5 - 5  of FIG. 3 respectively;  
         [0014]    [0014]FIG. 6 is a perspective view of the bicycle of FIG. 2 with the length thereof being adjusted to a minimum and the seat post removed to be inserted into the horizontal tube;  
         [0015]    [0015]FIG. 7 is a view similar to FIG. 6, where the seat post is inserted into the horizontal tube and the stem is folded down;  
         [0016]    [0016]FIG. 8 is a perspective view of the bicycle of FIG. 7 stored in a bag for storage;  
         [0017]    [0017]FIG. 9 is an exploded perspective view of a second preferred embodiment of portable bicycle according to the invention;  
         [0018]    [0018]FIG. 10 is an enlarged view of the components around the seat tube and the rear bar of FIG. 9;  
         [0019]    [0019]FIG. 11 is a perspective view of the assembled bicycle of FIG. 9; and  
         [0020]    [0020]FIG. 12 is a perspective view of the bicycle of FIG. 11 with the length thereof being adjusted to a minimum and the seat post removed and inserted into the horizontal tube. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    Referring to FIGS.  1  to  8 , there is shown a portable bicycle constructed in accordance with a first preferred embodiment of the invention. The bicycle comprises a front frame section  10  and a rear frame section  20  releasably coupled to the front frame section  10  by a fastening mechanism in which a size of the bicycle is also adapted to reduce to a minimum after disassembly as detailed later. The front frame section  10  comprises a head tube  12 , a fork  14 , a handlebar  13 , a stem  16  interconnected the handlebar  13  and the head tube  12 , a front wheel  15  releasably coupled to the fork  14  by mean of a well known quick release, two bearings (not shown) provided between the fork  14  and the head tube  12  so that the handlebar  13  are adapted to turn a predetermined angle, and a hinge  17  provided at the joining portion of the head tube  12  and the stem  16  so that the stem  16  is adapted to fold downwardly from the hinge  17  (see FIG. 7).  
         [0022]    The rear frame section  20  comprises a bottom bracket  35 , a pair of pedals  27  coupled to the bottom bracket  35 , a sprocket wheel  21  coupled to the bottom bracket  35 , a rear wheel  25 , and a chain stay  29  extended rearwardly from the bottom bracket  35  to an axle of the rear wheel  25 .  
         [0023]    As shown in FIG. 5, the rear frame section  20  further comprises a lower seat tube  24  extended upwardly from the bottom bracket  35 , an upper seat tube  26  spaced and aligned with the lower seat tube  24 , a seat stay  28  having a rear end coupled to the axle of the rear wheel  25 , and a seat post  23  slidably inserted into the upper seat tube  26  and the lower seat tube  24  as detailed later, the seat post  23  having a top saddle  55 .  
         [0024]    A crossbar comprises a horizontal, hollow front bar  11  including a front end fixedly coupled to the head tube  12 , one or more substantially vertical channels  18  (one is shown), and a lengthwise first groove  36  terminated at a rear end (see FIG. 4). A cap  53  is adapted to matingly couple to the rear end of the front bar  11  so that articles such as umbrella, air pump, etc. stored in the front bar  11  can be prevented from leaving accidentally.  
         [0025]    The crossbar further comprises a horizontal, hollow rear bar  22  including a top aperture  33  and a bottom aperture  34  with the seat tube passed therebetween. Front opening  70  and rear opening  71  of the rear bar  22  is reduced in diameter. Also, an outer diameter of the front bar  11  is about the same as an inner diameter of either opening  70  or  71  so that the front bar  11  is adapted to slide through the openings  70  and  71 . A lengthwise second groove  37  is formed on the rear bar  22 . The second groove  37  is matingly coupled to an outer surface of the first groove  36  for facilitating a correct coupling of the rear bar  22  and the front bar  11  and preventing both from turning each other. Two T-shaped gaps  38  and  39  are formed adjacent the front opening  70  and the rear opening  71  respectively so as to provide flexibility thereto.  
         [0026]    The rear bar  22  and the inserted front bar  11  are secured together by fastening first and second fastening members  30  and  31  at the front T-shaped gap  38  and the rear T-shaped gap  39  by flexibly deforming the T-shaped gaps  38  and  39  respectively. In detail, as seen in FIG. 4, a bolt  41  of the first quick release  30  is inserted through the holes of two flat, opposite ends (i.e., lugs) of a C-ring  44  to be threadedly coupled to a nut  42 . A ridge  45  is formed on an inner surface of the first fastening member  30 . The ridge  45  is adapted to matingly engage with both the first and second grooves  36  and  37  for positioning. A driver may counterclockwise turn the arcuate lever  43  of the first fastening member  30  to cause its cam end to exert force on the ends of the C-ring  44  for pulling toward each other. The rear bar  22  thus exerts force to clamp around the front bar  11  for fastening. To the contrary, a reverse operation of the lever  43  can unfasten the front bar  11  and the rear bar  22 . The second fastening member  31  will not be described in detail below since it is a mirror image of the first fastening member  30 .  
         [0027]    Moreover, an oblique down tube  32  as a reinforcement is interconnected the rear bar  22  and the lower seat tube  24 . The rear bar  22 , the lower seat tube  24 , and the down tube  32  form a triangle. Likewise, the seat stay  28 , the chain stay  29 , and the lower seat tube  24  form another triangle. As a result, the frame strength of the bicycle is increased greatly.  
         [0028]    A driver may insert the seat post  23  through the upper seat tube  26  and the channel  18  into the lower seat tube  24  until a desired height of the saddle  55  is reached. Next, the driver may manipulate a third fastening member  51  at a top opening of the upper seat tube  26  in a manner similar to the operation of either first or second fastening member  30  or  31  for securing the seat post  23  to the upper seat tube  26  (i.e., height adjustment).  
         [0029]    As shown in FIGS.  6  to  8 , for collapsing the bicycle the driver may unfasten the third fastening member  51  prior to detaching both the seat post  23  and the saddle  55 . Next, unfasten both the first and second fastening members  30  and  31  prior to sliding the front bar  11  with respect to the rear bar  22  until a minimum length of the bicycle (i.e., a minimum distance from the front wheel  15  to the rear wheel  25 ) is obtained so as to be compact. Next, fasten the first and second fastening members  30  and  31  again. The detached seat post  23  is adapted to snugly insert into a horizontal tube  60  extended rearwardly from the lower seat tube  24 . Optionally, the driver may rotate the saddle  55  an angle so as not to interfere with the front bar  11 . Next, the driver may drive a bolt  61  into the horizontal tube  60  for fastening the seat post  23  in the horizontal tube  60 . Finally, fold the stem  16  downwardly at the hinge  17  (see FIG. 7). The bicycle having the reduced size is thus adapted to store, for example, in a bag  62  for carrying or the trunk of a car prior to going for an outing (see FIG. 8). Preferably, the bag  62  has a zipper in the bottom so that either the front wheel  15  or the rear wheel  25  may be exposed. Thus, the driver may pull the handle of the bag  62  forward with the wheel being rotated along a supporting surface.  
         [0030]    Note that each of the fastening members  30 ,  31 , and  51  is implemented as a commercially available ring fastener, quick release, or the like. In the embodiment, the cross-section of the front bar  11  or the rear bar  22  is circle as shown in FIG. 5, while it is appreciated by those skilled in the art that the cross-section of the front bar  11  or the rear bar  22  may be any of other shapes such as oval or rectangle without departing from the scope and spirit of the invention.  
         [0031]    Referring to FIGS.  9  to  12 , there is shown a portable bicycle constructed in accordance with a second preferred embodiment of the invention. The second preferred embodiment substantially has same structure as the first preferred embodiment. The differences between the first and the second preferred embodiments, i.e., the characteristics of the second preferred embodiment are detailed below. The length of the front bar  11 ′ is shorter than that of the front bar  11  so that in a position adapted to ride the front bar  11 ′ does not project from the rear opening  71 ′ of the rear bar  22 ′ (see FIG. 11). Instead, the rear end of the front bar  11 ′ is stopped by the seat post  23  inserted into the upper seat tube  26  and the lower seat tube  24 . Thus, the front bar  11 ′ does not have any substantially vertical channels  18  such that the structural strength of the front bar  11 ′ can be further increased.  
         [0032]    The T-shaped gap  39  is eliminated by additionally providing a H-shaped gap  39 ′ on an outer surface of the rear bar  22 ′ proximate the joining portion of the lower seat tube  24  and the rear bar  22 ′ so as to provide flexibility thereat (see FIG. 10). An upper flexible member  72  and a lower flexible member  73  are formed by the gap  39 ′. Upper and lower lugs  74  and  75  are extended outwardly from the upper and lower flexible members  72  and  73  respectively. A bolt  41 ′ of the second fastening member  31 ′ is adapted to insert through the upper and lower lugs  74  and  75  to be threadedly coupled to a nut  42 ′. An arcuate lever  43 ′ having a cam end pivotably coupled to the head of the bolt  41 ′. A counterclockwise turning of the lever  43 ′ causes the cam to exert force to pull the upper and lower lugs  74  and  75  toward each other by flexibly deforming the upper and lower flexible members  72  and  73  (i.e., fastening the front bar  11 ′). To the contrary, a clockwise turning of the lever  43 ′ causes the cam to release the force to pull the upper and lower lugs  74  and  75  away from each other (i.e., unfastening the front bar  11 ′).  
         [0033]    The collapsing operation of the bicycle of the second preferred embodiment will be described in detail below by referring to FIG. 12. A driver may unfasten the third fastening member  51  prior to detaching both the seat post  23  and the saddle  55 . Next, unfasten both the first and second fastening members  30  and  31 ′ prior to sliding the front bar  11 ′ with respect to the rear bar  22 ′ until a minimum length of the bicycle (i.e., a minimum distance from the front wheel  15  to the rear wheel  25 ) is obtained with the front bar  11 ′ projected from the rear opening  71 ′ of the rear bar  22 ′ to dispose above the rear wheel  25 . The bicycle having such reduced size is thus adapted for storing, parking, or carrying in the trunk of a car prior to going for an outing.  
         [0034]    Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.