Abstract:
A folding or collapsible bicycle includes a bifurcated solid frame defining a first storage space and a second storage space. The front and rear wheels are held by pivoting forks that can be selectively moved from an operational position to a closed position in the closed position, the front wheel is disposed in the first storage space and the rear wheel is disposed in the second storage space.

Description:
BACKGROUND OF THE INVENTION 
   a. Field of Invention 
   This application pertains to a bicycle that has a solid frame and several members, including front and rear wheels, handle bars, and foot pedals that fold into a cavity formed in the frame to thereby provide a compact package. 
   b. Description of the Prior Art 
   The modern bicycle has been invented in the 19 th  century and is still very popular as a means of transportation and recreation all over the world. While various improvements have been made over the years making the bicycle faster, lighter, easier to use, and safer, its basic shape, structure and operation has not changed. One basic problem that still remains with the standard bicycle is that even if it is made of light materials, it is relatively large and difficult to store and carry. 
   While folding bicycles have been made in the past, none of them are really popular (especially with a younger crowd). One problem with known folding bicycles is that they are clumsy and difficult to fold. Another problem is that they require a lot of space to open and close. A further problem is that they are difficult to operate. Yet another problem with most folding bicycles is that they use either a non-standard structure and frame, or have a frame that is folded or otherwise distorted. Inherently, a bicycle with a folding frame is unstable and overly complicated. 
   SUMMARY OF THE INVENTION 
   A collapsible bicycle includes a solid frame having a front frame portion, a bifurcated center frame portion arranged to define a first storage space, and a bifurcated rear frame portion arranged to define a second storage space; a front wheel portion including a handle bar assembly attached to said front frame portion and a front wheel, said front wheel attached to said handle bar and being pivotable between an open position and a closed position, in said closed position, said front wheel being disposed in said first storage space; and a rear wheel portion attached to said rear frame portion and including a rear wheel and a rear wheel pivotable between an open position and a closed position, in said closed position said rear wheel being disposed in said second storage space. An adjustable seat support and a seat attached to said seat support. 
   The frame includes two hollow vertical members and the adjustable seat support includes two rods telescopically received within said hollow vertical members and a latch securing said two rods at one of several positions. A chain drive is also provided that includes pedals, a chain wheel and a chain for rotating said rear wheel. 
   The bicycle may include a locking hinge coupling said pedals to said chain wheel, said locking hinge selectively positioning said pedals into one of an operational and a closed positions. 
   The bicycle may have its front portion include a locking hinge selectively coupling said front wheel to said chain wheel, said locking hinge selectively locking said chain wheel to said handle bar assembly in said open position. 
   In addition, the bicycle may include a front latch for locking said front wheel in said closed position. 
   The bicycle may have the rear portion include a first rear latch selectively locking said rear wheel to said frame in said open position. 

   
     BRIEF DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a side view of a bicycle constructed in accordance with the present invention; 
       FIGS. 2–4  show details in respective top views of the handle bars being selectively folded into a downward storage position; 
       FIGS. 5–7  show the top end of the front fork being selectively disengaged from the frame; 
       FIGS. 8–10  show a locking mechanism engaging the front fork in the locked position; 
       FIGS. 11 and 12  show the locking mechanism for the seat and the manner in which the seat is disengaged and lowered to the locked position; 
       FIGS. 13–15  show details of the pedal and how it is pivoted to a folded position; 
       FIGS. 16–19  shows the mechanism for folding the rear wheel; 
       FIG. 20  shows details of how the chain path is adjusted while the back wheel is folded; and 
       FIG. 21  show a side view of the folded bicycle. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring first to  FIG. 1 , a bicycle  10  constructed in accordance with this invention includes a solid frame  12 , a front portion  14 , a rear portion  16 , a drive portion  18  and a seat portion  20 .  FIG. 1  illustrates the bicycle  10  in an open or operational configuration. In this position, the bicycle  10  looks just like any other standard bicycle and operates in the same manner. 
   Importantly, the bicycle  10  can be folded or collapsed into a closed configuration so that it can be stored easily in a locker, closet, or even the trunk of a car. As it will become apparent from the following description, as the bicycle is collapsed, its frame  12  remains an integral single unit which does not change shape while the other portions recited above are all pivoted and/or folded with respect to the frame. 
   In order to provide a clear understanding of the structure and components of bicycle  10 , its elements are first described in detail in the open configuration, and then a description will be provided of how each of the portions described above pivots or folds into the frame  12 . 
   Frame  12  includes a sleeve  22  interfacing with and supporting the front portion  14 . Welded to the sleeve  22  there are two upper members  24 A,  24 B, and two diagonal members  26 A,  26 B. (Members  24 B,  26 B are seen in  FIG. 8 ). Each upper of the upper members  24 A,  24 B is connected to the respective diagonal member by a respective, generally vertical, member  28 A,  28 B. Members  24 A,  24 B extend past members  28 A,  28 B and are attached to respective arcuate members  30 A,  30 B. The diagonal members  28 A,  28 B have horizontal extensions  32 A,  32 B. The distal ends of the extensions  32 A,  32 B are attached to the distal ends of the arcuate members  30 A,  30 B to form support plates  34 A,  34 B, respectively. As discussed above, frame  12  is solid, meaning that its elements do not pivot or fold as the bicycle is collapsed. 
   The front portion  14  includes an L-shaped axle with a leg  102  extending into the sleeve  22 , and an arm  104  extending forwardly. Two handle bars  106 A,  106 B are attached to and, in the open configuration, they extend outwardly of arm  104  in the usual manner. The bottom part of leg  104  is attached to a fork  110  by a locking hinge  112 . The fork  110  holds a standard front wheel  114  in the usual manner. A standard hand-brake  116  is provided in front of the fork  110 . Briefly, portion  14  is collapsed by causing the two handles  106 A,  106 B to pivot downward with respect to arm  104 , as indicated by arrows A (described in more detail in conjunction with  FIGS. 2–4 ) and by causing the fork  110  and wheel  114  to pivot backward in the direction indicated by arrow B (described in more detail in conjunction with  FIGS. 5–10 ). 
   The rear portion  16  includes a fork  200  that is attached to the extensions  32 A,  32 B by a locking hinge  202 . The distal end of the fork supports the rear wheel  204 . Wheel  204  has a standard axle with a built-in optional friction brake and other standard elements. As described more fully below, the rear portion is collapsed by pivoting the wheel  204  upward around hinge  202  toward the frame  12 , as indicated by arrow C. 
   The drive portion  18  includes a standard chain wheel  300 , a chain  302 , two paddle assemblies  304 A,  304 B and a derailleur assembly  306  (shown in  FIG. 19 ). The pedal assemblies  304 A,  304 B each include an arm  308  and a pedal  310  supported by a locking hinge  312 . In the position shown in  FIG. 1 , the pedals  310  are rotatable about a respective horizontal axle  314  in the usual manner to thereby propel the bicycle forward. As part of the collapsing process, the axles are rotated by about 90 degrees with respect to the hinges  312  so that the pedals  310  become parallel to arms  308 , as shown in  FIGS. 13–15 . 
   Finally, the seat portion  20  includes two posts  400 A,  400 B that are inserted into vertical members  28 A,  28 B respectively. The posts can be moved up and down as desired and their position is controlled by a latching mechanism  402  described in more detail in  FIGS. 11 and 12 . The posts  400 A,  400 B support a seat  404 . When the bicycle is collapsed, the seat  404  is lowered toward the frame, as indicated by arrow D. 
   Referring now to  FIGS. 2–4 , each of the handles  106 A,  106 B are attached to the arm  104  by a respective locking hinge  120 . Each locking hinge includes a housing  122  secured to arm  104 . The housing  122  is shaped to allow a trapezoidal bar  124  to move vertically up and down. Each bar  124  is terminated by a head  126  and has an oblique surface  128  on one side. Each bar is urged upward by a coil spring  130 . 
   The housings  122  further include a sidewall  132  supporting a horizontal pin  134 . The handle bars  106 A,  106 B are formed on their bottom with a horizontal leg  136  with a hole  138 , with the pin  134  extending through the hole  138 , thereby allowing the handles to pivot with respect to the housing  122 . Each leg  136  has a generally D-shaped cross section, with a flat segment  140 . As shown in  FIG. 2 , when the handle bars  106 A,  106 B are in the upright, or operational position, the flat segment  140  is in contact with the oblique surface  128  in bar  124  and this contact is what maintains the handles in this position. Any downward force on the handle bars  106 A,  106 B is resisted by the bars  124  and therefore the handle bars are maintained in their upright positions very solidly and securely, without any play between the handle bars and the housing  122 , or frame  12 . 
   The two heads  126  are positioned relatively close to each other so that they can be pressed down simultaneously, as shown by arrows E in  FIG. 3 , causing bars  124  to move downwards. This action causes the oblique walls  128  to disengage from segments  140 . As a result, the handle bars  106 A,  106 B then pivot around the axis of pins  134  until they move down to the position shown in  FIG. 4 . The pins  134  can be made integral with the housing, in which case the handle bars pivot around the pins, or the pins can be made integral with the handle bars, in which case the pins pivot together with the handle bars. From the positions shown in  FIG. 4 , the handles can be raised easily back to the upright position. When the handle bars do reach their upright position, the bar  124  jumps up because of the action of spring  130  and locks the respective handle bar in place. 
   Referring now to  FIGS. 5–10 , the fork  110  and front wheel  114  are pivoted with respect to the frame as follows. The fork  110  has a flange  150  seen in detail in  FIGS. 6 and 7 , with two holes  152 ,  154 . Each hole houses a respective pin  152 A,  154 A. Attached to the bottom of leg  102 , under sleeve  22  there is a flange  161  with a hole  165  receiving pin  152 A. The flange  161  also has an extension  163  receiving an end of a coil spring  156 . 
   A clamp  160  is used to secure the fork  110  to the flange  161 . The clamp  160  has a bottom portion  162  engaged by pin  154 A, a top portion shaped to form a handle  164 , a lip  166  and an arm  168 . The end of the arm  168  is attached to the other end of coil spring  156 , as seen in  FIG. 5 . 
   In the operational position of  FIG. 5 , the fork  110  is aligned or coaxial with the leg  102 . In this position, as seen in  FIGS. 5 and 6 , the lip  166  is positioned over, and is in contact with a top surface of flange  161 . The spring  156  biases the clamp  160  in the clockwise direction, thereby causing the clamp  160  and its lip  166  to push down on flange  161 . In this manner the fork  110  and wheel  114  are held securely to the leg  102  without any play therebetween, in a manner similar to a standard bicycle. In order to release the fork  110  and allow it to pivot, the handle  164  is pivoted forward, around pin  154 A, in the direction of arrow E, against the biasing of the spring  156 . This action causes the lip  166  to disengage and move away from the flange  161 , and the gravity then causes the wheel to pivot about pin  152 A and move backward as indicated by arrow B. 
   Preferably, as seen in  FIG. 8 , there are two springs, one on each side of sleeve  22  to insure that the fork  110  is held securely. 
   Referring to  FIGS. 8–10 , a curved or S-shaped latch  170  pivoting on a pin  172  attached to member  24 B. Two brackets  174 ,  176 , attached to members  24 B,  26 B guide and limit the movement of the latch laterally so that the latch won&#39;t bend sideways and cause injury to a biker. The latch  170  terminates with a hook  178 . The bottom of fork  110  is formed with a hole  180 . As previously mentioned, the fork  110  and wheel  114  are released by moving the clamp  160  to move forward. Gravity or a push with the hand causes the fork  110  and wheel  114  to move backward until the fork  110  is substantially horizontal and the hook  178  enters into hole  180  and latches the fork  110  as shown in  FIGS. 8 and 9 . The fork  110  and the wheel  114  are maintained in this closed position by the latch  170 . 
   In order to return the wheel  114  to the operating position, while the frame  12  is held up in the air, the latch  170  is raised upward, as indicated in  FIG. 8  by arrow F. This action causes the hook  178  to disengage from hole  180  thereby releasing the fork  110 . The fork  110  and wheel  114  are then forced by gravity to swing forward until the clamp  160  engages the flange  161  thereby locking the fork  110  into the operational configuration. 
     FIGS. 11 and 12  show the structure of seat portion  20 . It includes hollow posts  400 A,  400 B supporting seat  404 , as well as a lever  406  secured to a pin  410 . Pin  410  extends between two brackets  408  that are mounted member  28 A,  28 B. Pin  410  also supports two claws  414  disposed adjacent to members  28 A,  28 B. Members  28 A,  28 B each have a hole  416 . Posts  400 A,  400 B are provided with a plurality of axially spaced holes  420  similar in size and shape to holes  416 . A spring  412  biases the lever  406  toward a downward position. In this position, the claws  414  are forced through holes  416  into one of the holes  420 . 
   If a biker wants to change the height of seat  404 , all he has to do is lift the lever  406  upward in the direction indicated by arrow G. This action causes the pin to rotate clockwise thereby withdrawing the claws  414  from holes  420  and thereby leaving the posts free to move up or down telescopically within the members  28 A,  28 B, as indicated by arrow H. Moreover, for the closed position of the bicycle, preferably, the seat is moved all the way down. 
     FIGS. 13–15  show details of the pedal assembly  304 A. As seen in these drawings, the pedal  310  is rotatably mounted on a shaft  314 . Shaft  314  is mounted on a locking hinge  312 . The locking hinge  312  includes a bracket  318  receiving shaft  314  and a claw  320  extending into the arm  308 . The hinge  312  further includes a pin  322  supported by a sidewall  324  of the arm  308 . Claw  320  is terminated with a surface  325  disposed at an angle of about 45 degrees. Also inside arm  308  there is provided a ledge  326 . A rod  328  passes through a hole (not shown) in ledge  326  and has a bottom member  330  terminating in a surface  332 . Surface  332  is also disposed at an angle of 45 degrees. A spring  334  is disposed between ledge  326  and member  330  and bias the member  330  in a downward direction so that the surfaces  332  and  326  are in contact with each other. As a result of this structure, the locking hinge  312  holds the axle  314  and pedal  310  in a horizontal orientation and does not allow the pedal to rotate with respect to the axis of pin  322 . 
   The arm  308  is mounted on a standard shaft  336  supporting the chain wheel  300 . Mounted around this shaft is a lever  338  with a sleeve  340 . A thin cable  342  has one end secured to the sleeve  340  and it is at least partially trained around this sleeve, as seen in  FIG. 14 . The other end of the cable  342  is secured to rod  328 , as seen in  FIG. 13 . The lever  338 , sleeve  340  and cable  342  are constructed and arranged so that when lever  338  is rotated around shaft  336  in the direction of arrow I, more of the cable  342  is wound onto the sleeve  340  causing the rod  328  and its bottom member  330  to lift upward. This action causes the surface  332  to lift upward and disengage from surface  325 . Once contact between the two surfaces  332 ,  325  is broken, the pedal  310  is free to turn with respect to pin  322 . The actual rotation or pivoting may be done manually, or a spring may be used to urge the pedal to pivot in the direction of arrow J in  FIG. 15 . During this motion, the claw  320  is pivoted behind the pin  322  as seen in  FIG. 15 . Once the claw  320  pivots past surface  332 , the lever  338  can be released and surface  332  is returned toward its downward position thereby engaging the claw  320  and maintaining it in the position shown in  FIG. 15 . The pedal  310  is rotated to the position of  FIG. 15  while the bicycle is folded toward its closed position. 
   As the bicycle returns to the open position, the pedal  310  can be returned to the position of  FIG. 13  by hand or foot. When the pedal reaches its horizontal position, the two surfaces  332  and  325  come into contact once again thereby immobilizing the pedal in the position of  FIG. 13 . 
     FIGS. 16–20  illustrate the operation of the rear portion  16 . The rear portion  16  has three functions: it provides the mechanism for moving the rear wheel  204  up to a position adjacent to the seat, it provides for movement of the chain wheel  300  upward, and it provides for the tightening of the chain  302  so that it does not get tangled up while the bicycle is in the closed position. The three functions and the elements performing these functions are interconnected and therefore they are described together. 
   Referring first to  FIGS. 16 and 18 , the chain wheel  300  is supported by a sleeve  210  mounted on an arm  212 . The sleeve  210  has a pivoting pin  214  supporting a curved plate  216 . The curved plate  216  can pivot about pin  214  with respect to sleeve  210 . The plate has two portions  216 A,  216 B. Portion  216 B is terminated with a claw  218 . A bar  220  is attached to frame member  26 B and extends diagonally downward as shown. The bar  220  terminates with a flat portion  222  with a hole  224 . When the bicycle  10  is in its operational mode, a spring  226  attached to the pin  214  applies a biasing force in the counterclockwise direction on plate  216  forcing the claw  218  into opening  224  of bar  220 . This action fixes and maintains the position of the chain wheel  300  with respect to the frame  12  to allow a biker to use the bicycle in the normal manner. Arm  212  includes a hole  230 . A pin  232  is provided on extension  32 B. A spring  234  extends from the pin  232  and engages hole  230 . This action applies an additional biasing force on the wheel  300  downward to make it steady and insure that the wheel  300  stays in the position shown even if the bicycle is subjected to shaking, for example, when it hits an obstruction. 
   As discussed above, the back portion includes a fork  200  holding the back wheel  204 . The fork  200  is formed of two segments 204 A and  204 B. In the operational configuration, the segments  200 A,  200 B are disposed approximately in parallel with the frame extensions  32 A,  32 B and are interconnected by the hinge  202 . As shown in  FIG. 16 , the hinge  202  is formed by a bracket  236  attached to frame extension  32 B and a pin  238 . The pin  238  supports an end of arm  212  and an end of fork segment  200 B. Adjacent to pin  238 , arm  212  has an opening  240 . This opening  240  receives and engages the end of a bar  242 . Bar  242  is generally in parallel to fork segment  204 B. 
   Referring now to  FIG. 19 , fork segment  204 B terminates with a plate  244 . Plate  244  has an opening  246  receiving the shaft  248  holding the rear wheel  204 . The plate  246  also has a longitudinal sleeve  250  arranged to receive and guiding the end of rod  242 . The plate  246  is terminated with a tongue  252 . The frame extension  32 B is continuous with arcuate frame member  30 B. Attached to frame member  30 B is a bracket  254  holding a pin  256 . A lever  258  is pivoting around pin  254  and is terminated with a horizontal portion  260 . A spring  262  is disposed between arcuate member  30 B and lever  258  and biases the lever  258  away from member  30 B as shown. In this position, the horizontal portion  260  is in contact with the tongue  252  and keeps the portion  200 B in a horizontal position. Rod  242  passes through the sleeve  250  and terminates adjacent to a vertical surface  258 A of lever  258 . Another rod similar to rod  242  is disposed on the other side of the bicycle and extends adjacent to a lever essentially identical to lever  258 . 
   In the position shown in  FIGS. 1 ,  16  and  19 , the chain  302  passes over chain wheel  300 , and, as shown in  FIG. 19  to another chain wheel  264  on the axle of the rear wheel  204 . From the chain wheel  264  the chain  302  returns through derailleur  306  back to chain wheel  300  in the usual manner for advancing the bicycle. 
   The rear wheel  204  is collapsed as follows. Returning to  FIGS. 16 , the plate  216  is positioned so that when the front wheel  114  is collapsed backward, the wheel  114  comes into contact with the plate  216  (and more specifically, the plate portion  216 A). This action causes the plate  216  to pivot in the clockwise direction as indicated by arrow I, and to retract the claw  218  from hole  224  thereby disengaging the plate  216  from bar  220 . The front wheel  114  moves further back causing the chain wheel  300  and arm  212  to pivot clockwise, as shown by arrow J in  FIG. 16 . This pivoting of arm  212  causes the rod  242  to move backwards. 
   Returning to  FIG. 19 , as the rod  242  (and the corresponding rod on the other side of the wheel  204 ) moves backwards, in the direction indicated by arrow K, the end of rod  242  comes into contact with surface  258 A and thereafter the rod  242  pushes the lever  258  so that the lever pivots clockwise, as indicated by arrow L about pin  256 . This movement of lever  258  causes its segment  260  to slide off and disengage from the tongue  252 . This action occurs simultaneously on both sides of wheel  204 . Once these two elements are disengaged, the weight of the frame  22  causes it to move downward so that the frame lowers over and envelopes a substantial portion of the rear wheel  204 . Because fork segment  200 B is attached to pin, as the frame  22  moves downwards over the wheel  204 , the wheel  204  and fork portions  200 A,  200 B pivot clockwise in the direction shown by arrow M in  FIG. 20 . 
   Arcuate member  30 B is also provided with a handle  270 . The handle is pivotably attached to the member  30 B by a pin  272 . A spring mounted on the pin (not shown) is biasing the handle  270  toward the position shown in  FIG. 20 . The handle includes a flat shoulder  274  and a caming surface  275 . A bracket  276  is used to guide and control the movement of the handle  270 . As discussed above, after the rod  242  releases the segment  200 B from lever  258 , these two latter members start rotating clockwise as indicated by arrow M. As this motion continues, the end of the rod  242  hits the caming surface  275  and causes the handle to move slightly outwards until the end of rod  242  clears the handle. The wheel  204 , the frame  20 , the segment  200 B and the rod  242  are sized and shaped so that as the wheel  204  goes into the frame as far as it can, the end of the rod  242  clears the handle  270 . The handle  270  returns to its original position and the surface  274  comes into contact with the end of the rod  242 . This action takes place substantially simultaneously on both sides of the frame. The wheel  204  has now reached its closed position and is maintained in this position by the interaction between handle  270  (and its surface  274 ) and the end of rod  242 . 
   The frame extension  32 B is provided with an extra small wheel  307 . Between the derailleur  306  and the chain wheel  264 , the chain passes over the wheel  307  as shown in  FIG. 20 , the wheel being positioned to insure that the chain  302  is not lose and tangled up while the wheel  204  is moving into and out of the frame. 
   The wheel  204  can be released by lifting the rear portion of the bicycle and pivoting handle  270  as indicated by arrow N. This action causes the surface  274  to disengage from rod  242  and the wheel  204  is then allowed to dropped out of the frame until the tongue  256  falls below the portion  260  of lever  258  ( FIG. 19 ). 
   The closed configuration of the bicycle is shown in  FIG. 21 . This configuration is made possible by the bifurcate nature of the frame so that both the front and rear wheels can be adequately held between the respective frame members without breaking the same. Obviously, this configuration is small and compact and has no extraneous members that could interfere with the movement of a person carrying it. The bicycle can also be stored in this configuration easily. 
   The bicycle  10  is unfolded or expanded from the closed configuration of  FIG. 21  to the open or operational configuration of  FIG. 1  as follows. First, the two handle bars  106 ,  108  are folded back to the upward position. Next, the front end of the bicycle  10  is lifted with one hand holding one of the handle bars or the frame  20  and the latch  170  is elevated. The wheel  114  drops down and swings forward until its fork is attached to the arm  102  as discussed above. 
   Next, the rear of the bicycle  10  is lifted and the handle  270  is raised allowing the rear wheel  204  to dropped down. 
   Next, the pedals  310  are released by pulling on levers  338 . Finally the seat is adjusted by raising lever  406 . 
   Thus, as can be seen from the above description, the bicycle can be quickly collapsed from the open to the closed configuration and then back to the open configuration in a couple of quick and easy steps. Moreover, the bifurcated frame allows the wheels and other elements to be collapsed effectively within the frame thereby insuring that in the collapsed or closed configuration the bicycle requires a relatively small amount of space. 
   Numerous modifications may be made to this invention without departing from its scope as defined in the appended claims.