Abstract:
A folding type bicycle including a front frame provided with a front wheel and a handle, a center frame provided with pedals and a saddle, a rear frame provided with a rear wheel, a hinge device to enable the front frame, the center frame and the rear frame to pivot about one another, to be foldable with respect to one another, the hinge device comprising a front hinge member provided at the front frame, a center hinge member provided at the center frame, and a rear hinge member provided at the rear frame, and a hinge shaft configured to support a front hub, which is provided at a center of the front hinge member, a center hub, which is provided at a center of the center hinge member, and a rear hub, which is provided at a center of the rear hinge member, the hinge shaft passing through the front hub, the center hub and the rear hub, wherein the hinge shaft enables the supporting on at least two positions that are spaced apart from each other in a longitudinal direction of the hinge shaft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 2012-0104085, filed on Sep. 19, 2012 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     Embodiments of the present invention relate to a bicycle foldable for convenient storage and transportation thereof. 
     2. Description of the Related Art 
     Bicycles, which are short-distance traveling means, are widely used for exercise or leisure. 
     Generally, such a bicycle includes a frame constituting a skeleton of the bicycle, and wheels, pedals and a handle, which are mounted to the frame. Basically, the bicycle is traveled by force transmitted to the wheels via a chain after being generated when the user steps the pedals to rotate a sprocket. 
     Conventional bicycles are inconvenient in storage and transportation because they employ an integrated frame. In order to solve such a problem, a bicycle having a foldable frame has recently been developed. 
     Such a bicycle is disclosed in Korean Utility Model No. 20-0341604 (registered on Feb. 2, 2004). In the disclosed bicycle, a frame, to which a front wheel and a rear wheel are rotatably mounted, is foldable in half about a portion thereof where a saddle is installed. However, this bicycle has an inconvenient and bulky folding structure. 
     SUMMARY 
     Therefore, it is an aspect of the present invention to provide a folding type bicycle having a convenient and compact folding structure. 
     Another aspect of the present invention is to provide a folding type bicycle capable of being stably maintained in an unfolded state. 
     Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     In accordance with one aspect of the present invention, a folding type bicycle includes a front frame, a center frame, a rear frame, a hinge device and a hinge shaft. The front frame may be provided with a front wheel and a handle. The center frame may be provided with pedals and a saddle. The rear frame may be provided with a rear wheel. The hinge device may be configured to enable the front frame, the center frame and the rear frame to pivot about one another, to be foldable with respect to one another, the hinge device including a front hinge member provided at the front frame, a center hinge member provided at the center frame, and a rear hinge member provided at the rear frame. The hinge shaft may be configured to support a front hub, which is provided at a center of the front hinge member, a center hub, which is provided at a center of the center hinge member, and a rear hub, which is provided at a center of the rear hinge member, the hinge shaft passing through the front hub, the center hub and the rear hub. The hinge shaft may enable the supporting on at least two positions that are spaced apart from each other in a longitudinal direction of the hinge shaft. 
     The two positions may respectively correspond to the center hub and a ring bracket that is provided at a space between the front hub and the center hub or at a space between the rear hub and the center hub. 
     The ring bracket may include a ring mount, which is coupled to the front hub or the rear hub, and a bearing mount that extends from the ring mount. 
     Each of the center hub and the ring bracket may be coupled to the hinge shaft while interposing a bearing therebetween. 
     The front frame and the rear frame may include a front rim and a rear rim, respectively, and the center frame may be provided with a plurality of rolling members configured to rotatably contact with the front rim and the rear rim. 
     Each of the front and rear rims may include rim guides each having an arc shape, and rim protrusions extending from opposite ends of each of the rim guides, respectively. Each of the rolling members may include a cylinder fitted in a fitting hole formed at the center frame, and rollers respectively fitted around opposite ends of the cylinder, to rotatably contact corresponding ones of the rim guides of the front and rear rims. 
     Each of the rim guides and the rim protrusions thereof define a sector shape, to limit movement of a corresponding one of the rolling members. 
     The hinge device may include an opening lever and a spacing member. The operating lever may be configured to pivot about the hinge shaft. The spacing member may be configured to adjust spacing among the front, center and rear frames in accordance with pivoting of the operating lever. 
     The spacing member may include a rotating cam and a fixed cam, which have facing cam surfaces, respectively. The rotating cam may be provided at the rear hub, to be fixed to the rear hub, and the fixed cam may be provided at the center hub, to be fixed to the center hub, such that spacing between the cam surfaces is adjusted in accordance with the pivoting of the operating lever. 
     The folding type bicycle may further include a generator, a battery, a motor, and an electronic control unit. The generator may be operatively connected to the pedals, to generate electrical energy during stepping of the pedals. The electronic control unit and the battery may be received in one of the front, center and rear frames, and the motor may be operatively connected to the rear wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a perspective view illustrating an unfolded state of a folding type electric bicycle according to an exemplary embodiment of the present invention; 
         FIG. 2  is a plan view illustrating the folding type electric bicycle according to the illustrated embodiment of the present invention; 
         FIG. 3  is a side view illustrating the folding type electric bicycle according to the illustrated embodiment of the present invention; 
         FIG. 4  is an exploded plan view illustrating a hinge device of the folding type electric bicycle according to the illustrated embodiment of the present invention; 
         FIG. 5  is an exploded perspective view illustrating the hinge device of the folding type electric bicycle according to the illustrated embodiment of the present invention; 
         FIG. 6  is a cross-sectional view taken along the line VI-VI in  FIG. 4 , to illustrate the hinge device; 
         FIG. 7  is a cross-sectional view taken along the line VII-VII in  FIG. 4 , to illustrate the hinge device; 
         FIG. 8  is a schematic view illustrating an operating lever of the folding type electric bicycle according to the illustrated embodiment of the present invention; and 
         FIG. 9  is a perspective view illustrating a folded state of the folding type electric bicycle according to the illustrated embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit and scope of the present invention to those skilled in the art. Other embodiments may also be provided. Constituent elements other than elements constituting essential features of the present invention may be omitted from the drawings, for clarity of description. In the drawings, the widths, lengths, and thicknesses of constituent elements may be exaggerated for clarity and convenience of illustration. Like reference numerals refer to like elements throughout. 
       FIG. 1  is a perspective view illustrating a folding type bicycle according to an exemplary embodiment of the present invention.  FIG. 2  is a plan view corresponding to  FIG. 1 .  FIG. 3  is a side view corresponding to  FIG. 1 . 
     Referring to  FIGS. 1 to 3 , the folding type bicycle according to the illustrated embodiment of the present invention includes a front frame  100  provided with a front wheel  10  and a handle  20 , a center frame  200  provided with pedals  30  and a saddle  40 , and a rear frame  300  provided with a rear wheel  50 . The frames  100 ,  200  and  300  are pivotally coupled to one another by a hinge device  400 . 
     The front frame  100  has a hollow bar structure having an inner space. The front frame  100  is provided, at one end thereof, with a handle tube  110  while being, provided, at the other end thereof, with a front hinge member  410 , to be pivotally coupled to the center frame  200 . 
     A handle stem  21  is rotatably fitted in the handle tube  110 , which is a hollow structure. The handle stem  21  is provided, at a lower end thereof, with a front wheel mounting frame  22  extending downwardly from a lower end of the handle tube  110 . The handle stem  21  is also provided, at an upper end thereof, with a handle mounting frame  23  extending upwardly from an upper end of the handle tube  110 . 
     The front wheel mounting frame  22  is laterally bent from a center of the handle stem  21 , to cause the front wheel  10  to be aligned with the rear wheel  50  along a line A ( FIG. 2 ). The handle mounting frame  23  supports a central portion of the handle bar  24 . For steering convenience of the user, respective handle grips  25  and respective brake levers  26  for braking of the front wheel  10  and rear wheel  50  are provided at opposite ends of the handle bar  24 . 
     A display device  27  is detachably mounted at one side of the handle bar  24 , to display information as to a speed change state and a battery amount in the case in which the bicycle is an electric bicycle. At the other side of the handle bar  24 , a lever  28  for acceleration and speed change is installed. 
     The center frame  200  has a hollow bar structure having an inner space. The center frame  200  is provided, at one end thereof, with a pair of pedals  30  while being, provided, at the other end thereof, with a center hinge member  430  to pivotally couple the front frame  100  and rear frame  300  to the center frame  200  at opposite sides of the center frame  200 , respectively. The pedals  30  are rotatable about a pedal coupler  210  provided at the center frame  200 . 
     A generator (not shown) is installed within the pedal coupler  202 , to convert rotational force of the pedal  30  into electrical energy. The electrical energy is charged in a battery  60 , which is electrically connected to the generator. An electrical control unit (ECU)  70  is installed within the center frame  200 , for electrical connection and control of the whole electrical elements including the generator and battery  60 . Since each of the frames  100 ,  200  and  300  has an inner space, the ECU  70  may be installed in one frame other than the center frame  200 , namely, the frame  100  or  300 . 
     The center frame  200  includes a saddle frame  220  for installation of the saddle  40 . 
     The saddle frame  220  is provided, at a rear side thereof, with a saddle tube  42  for installation of the saddle  40 . A saddle rod  52  is coupled to the saddle tube  42  in order to adjust the level of the saddle  40 . The saddle frame  220  may be integrated with the center frame  200 . Alternatively, the saddle frame  220  may be separate from the center frame  200 . In the latter case, the saddle frame  220  and center frame  200  may be assembled through welding or bolting. 
     The rear frame  300  has a hollow bar structure having an inner space. At one end of the rear frame  300 , the rear wheel  50  is rotatably installed. The rear frame  300  is also provided, at the other end thereof, with a rear hinge member  420 , to be pivotally coupled to the center frame  200 . 
     The battery  60  is installed within the inner space of the rear frame  300 , in which a battery management system (not shown), etc. are also installed. These elements are electrically connected to the ECU  70  provided at the center frame  200 . The rear wheel  50  is provided with a motor  52 , which receives power from the battery  60 , thereby rotating the rear wheel  50 . Since each of the frames  100 ,  200  and  300  has an inner space, as described above, the battery  60  may be installed in one frame other than the rear frame  300 , namely, the frame  100  or  200 . 
     Although no detailed description has been given of the front wheel  10  and rear frame  50 , the wheels  10  and  50  are provided with braking members, namely, discs  14  and  54  and frictional pads, respectively, to restrict rotational force during operation of the brake levers  26 . 
       FIGS. 4 and 5  are views for concretely explaining the hinge device  400  to pivotally couple the front frame  100 , center frame  200  and rear frame  300 . 
     Referring to  FIGS. 4 and 5 , the hinge device  400  includes the front hinge member  410 , which is provided at the other end of the front frame  100 , the rear hinge member  420 , which is provided at the other end of the rear frame  300 , and the center hinge member  430 , which is provided at the other end of the center frame  200 . The front hinge member  410  and rear hinge member  420  are coupled to left and right surfaces of the center hinge member  430 , respectively. 
     Each of the hinge members  410 ,  420  and  430  forms an inclination angle of 6° with respect to the line A, along which the front wheel  10  and rear wheel  50  are aligned. In accordance with the inclination angle, the front wheel  10  and rear wheel  50  are aligned in an unfolded state of the bicycle ( FIG. 1 ), and the front wheel  10  and rear wheel  50  are arranged in parallel in a folded state of the bicycle ( FIG. 9 ). 
     A hinge shaft  440  is centrally arranged within the hinge members  410 ,  420  and  430 . The hinge shaft  440  is fixedly mounted, at one end thereof, to the front hinge member  410  by a mount. An intermediate portion of the hinge shaft  440  extends through a center hub  432  centrally provided at the center hinge member  430 . The other end of the rear hinge member  420  is coupled to an operating lever  450  while extending through the rear hinge member  420 . 
     The center hinge member  430  includes a center rim  431  provided at a periphery of the center hinge member  430  for lightness of the center hinge member  430 , and a center hub  432  centrally provided at the center hinge member  430 . The center rim  431  and center hub  432  are connected by a plurality of ribs  433 . The hinge shaft  440  extends through a hole formed in the center hub  432 . 
     Similarly to the center hinge member  430 , the front hinge member  410  includes a front rim and a front hub, and the rear hinge member  420  includes a rear rim  421  and a rear hub  422 . Although the front rim and front hub are not shown, they have the same shapes as those of the rear rim  421  and rear hub  422 . 
     The operating lever  450  is provided at the rear hinge member  420  of the rear frame  300 , to pivot about the hinge shaft  440 . A lever cover  454  is provided at the operating lever  450 , to cover the other end of the hinge shaft  440 . 
     Meanwhile, the hinge device  400  also includes metal rings  460  respectively provided between facing rotational contact surfaces of the hinge members  410  and  430  and between facing rotational contact surfaces of the hinge members  420  and  430 , to achieve smooth pivoting of the hinge members  410 ,  420  and  430 . The hinge device  400  further includes a spacing member  470  to adjust the spacing among the hinge members  410 ,  420  and  430 , and rolling members  480  to achieve smooth pivoting of the hinge members  410 ,  420  and  430 . 
     The spacing member  470  includes a fixed cam  472  and a rotating cam  474  provided between the rear hinge member  420  and the operating lever  450 . 
     The fixed cam  472  is fitted, at a rear surface thereof, in a square fitting hole provided at the rear hub  422  of the rear hinge member  420 , to be fixed to the rear hinge member  420 . The rotating cam  474  is fitted, at a rear surface thereof, in a square fitting hole provided at the operating lever  450 , to be fixed to the operating lever  450 . 
     Cam surfaces  473  and  475  are provided at facing front surfaces of the fixed cam  472  and rotating cam  474 , respectively. Each of the cam surfaces  473  and  475  has a structure having mountains and valleys. Accordingly, when the operating lever  450  is positioned at a locking position, the cam surfaces  473  and  475  are in contact with each other between the mountains thereof, so that they are spaced apart from each other by 2 mm. On the other hand, when the operating lever  450  is positioned at an unlocking position, the cam surfaces  473  and  475  are in contact with each other between the mountains thereof and the valleys thereof, so that they close contact without spacing therebetween. The hinge shaft  440  extends through the fixed cam  472  and rotating cam  474  such that it does not interfere with the operations of the cam surfaces  473  and  475  of the fixed cam  472  and rotating cam  474 . A nut  479  is fastened to the other end of the hinge shaft  440  extending through the operating lever  450  via washers  476  and a needle bearing  478 . 
     Each rolling member  480  includes a cylinder  482  fitted in a fitting hole  435  of the center frame  200 , and rollers  484  respectively fitted around opposite ends of the cylinder  482 . 
     The rollers  484  rotatably contact rim guides  425  provided at a front rim of the front hinge member  410  and a rear rim  421  of the rear hinge member  420 , respectively, for rolling-contact of the front and rear hinge members  410  and  420  with the center hinge member  430 . 
     Each rim guide  425  includes a plurality of rim protrusions  426  to support rolling of the corresponding rollers  484  while limiting the lateral movement distance of the corresponding rollers  484 . That is, as shown in  FIG. 6 , a sector-shaped structure is formed by each rim guide  425 , which has an arc shape, and a pair of rim protrusions  426  protruded from opposite ends of the rim guide  425 . Within the sector-shaped structure, one roller  484  rolls between the opposite ends of the rim guide  425 . Thus, the pivotal movement distance of the frames  100  and  300  is effectively limited. 
     The hinge device  400  further includes a load-distributing support unit  490  to reduce a load repeatedly applied to the hinge shaft  450  by the weights of the frames  100  and  300  during folding and unfolding operations. 
     The load-distributing support unit  490  includes a ring mount  492  fitted around the hinge shaft  440  between the center frame  200  and the rear frame  300 , and a bearing  494  fitted in the ring mount  492 , to be interposed between the hinge shaft  440  and the ring mount  492 . The ring mount  492  is fixed to the rear hub  422  of the rear hinge member  420 . The bearing  494 , which is fitted in the ring mount  492 , effectively distributes the load applied to the hinge shaft  440 , at two points spaced apart from each other, together with a bearing  496  fitted in the center hub  432 . 
     The hinge device  400  further includes a locking pin member  500  extending through the hinge members  410 ,  420  and  430  in order to stably maintain the front frame  100 , center frame  200  and rear frame  300  in an unfolded state. 
     The locking pin member  500  includes a center pin  510  provided at the center frame  200  and a rear pin  520  provided at the rear frame  300 . 
     The center pin  510  is disposed in one of the fitting holes  435  provided at the center rim  431  of the hinge member  430 . In detail, the center pin  510  is fitted in the hole of the cylinder  482  fitted in the fitting hole  435 , in which the center pin  510  is disposed. An elastic member  512  is also installed in the cylinder  482 . The center pin  510  is normally disposed within the center hinge member  430  by the elastic member  512 . Upon receiving external force, the center pin  510  is protruded toward the front hinge member  410 . 
     The rear pin  520  is fitted in a fitting hole  429  provided at the rear rim  421  of the rear hinge member  420 . An elastic member  522  is also installed in the fitting hole  429 . In detail, the rear pin  520  is disposed such that a head  524  thereof is outwardly protruded from the rear hinge member  420  by the elastic member  522 . When external force is applied to the rear pin  520 , the head  524  is inserted into the rear hinge member  420 , and a tail  526  of the rear pin  520  opposite to the head  524  is protruded toward the center hinge member  430 . 
     The center pin  510  and rear pin  520  are aligned in the unfolded state of the bicycle, as shown in  FIG. 7 . On the other hand, the center pin  510  and rear pin  520  are spaced apart from each other in the folded state of the bicycle, as shown in FIG.  6 . 
     Hereinafter, operation of the electric bicycle having the above-described configuration according to the illustrated embodiment will be described. Although the electric bicycle as described above is illustrated in this embodiment, embodiments of the present invention may be easily implemented in general folding type bicycles by those skilled in the art, through modifications and changes, without being limited to the electric bicycle. 
     As shown in  FIGS. 1 to 3 , in the folding type bicycle according to the illustrated embodiment of the present invention, the front wheel  10  and rear wheel  50  are aligned along the line A in a completely unfolded state of the bicycle. 
       FIG. 8  is a view for explaining operation of the operating lever  450 . In the unfolded state of the bicycle, the operating lever  450  is received in a seating groove  423  provided at the rear hinge member  420 , as indicated by a dotted line in  FIG. 8 . On the other hand, in the folded state of the bicycle, the operating lever  450  is separated from the seating groove  423  of the rear hinge member  420 , as indicated by a solid line in  FIG. 8 . 
     In order to couple the operating lever  450  and locking pin member  500  at a correct position within the seating groove  423 , the head  524  of the rear pin  520  is provided with an engagement groove  527 , and the operating lever  450  is provided with an engagement lug  528  corresponding to the engagement groove  527 . 
     Upon folding the bicycle, the user pivots the operating lever  450  about the hinge shaft  440 . When the operating lever  450  is separated from the seating groove  423  of the rear frame  330 , the rear pin  520  of the locking pin member  500  is retracted by the elastic member  522  such that the head  524  is exposed. Since the rear pin  520  pushes the center pin  510  in the aligned state, the center pin  510  is elastically retracted toward the operating lever  450  by the elastic member  512  when the rear pin  520  is retracted. 
     In accordance with the retraction of the rear pin  520 , the tail  526  of the rear pin  520  is inserted into the fitting hole  429 . As a result, locking between the rear hinge member  420  and the center hinge member  430  is released. Similarly, the center pin  510  is inserted into the cylinder  482  thereof in accordance with the retraction thereof. As a result, locking between the center hinge member  430  and the front hinge member  410  is released. 
     When locking of the locking pin member  500  is released as described above, the user can fold the bicycle to the state of  FIG. 9  by pivoting the front frame  100  and rear frame  330  about the hinge device  400  at the left and right sides of the center frame  200 , respectively. In this case, the handle stem  21  is folded toward the front wheel  10  after release of a clamp  21   a . In the folded state, the user may easily move the bicycle to a desired location after grasping the saddle  40 . 
     Meanwhile, although the operating lever  450  is illustrated in this embodiment as being provided at the rear frame  300 , embodiments of the present invention are not limited thereto. For example, the operating lever  450  may be provided at the front frame  100 . 
     Also, although, in the illustrated embodiment, the rollers  484  of each rolling member  480  are provided at the center frame  200 , and the rim guides  425  to support rolling of the rollers  484  are provided at the front frame  100  and rear frame  300 , respectively, embodiments of the present invention are not limited thereto. For example, the positions of these elements may be reversed. That is, the cylinder and rollers  484  of each rolling member  480  may be provided at each of the front frame  100  and rear frame  300 , and a rim guide  425  to support the rollers  484  may be provided at the center frame  200 . 
     As apparent from the above description, the folding type bicycle according to the illustrated embodiment of the present invention may achieve a compact folding size because the front frame and rear frame are folded about the center frame such that the bicycle is folded in triple. 
     In the folding type bicycle according to the illustrated embodiment of the present invention, it may also be possible to stably and firmly maintain the unfolded state of the bicycle because the locking pin member extending through the front frame, center frame and rear frame is movable between a locking position and an unlocking position, only through operation of the operating lever. 
     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.