Abstract:
A tricycle includes a head tube with a post connected to a first end thereof and a front wheel is connected to a lower end of the head tube. A handle is foldably connected to the post. Two swing links pivotably connected to the head tube by a front wheel seat on the head tube and each swing link includes a footboard and a rear wheel connected to each of the footboards. Two pedals are pivotably connected to the two footboards and each pedal is cooperated with a driving unit which includes a rotary unit and driving unit. The rotary unit is activated by pressing the pedal and the driving unit can only drive the rear wheel in one direction. The user holds the handles and steps on the footboards, by twisting his or her body, the tricycle moves forward as conventional tricycle. By alternatively pressing the pedals, the rear wheels accelerate by the driving unit such that the tricycle can move faster. The handles, the two swing links and the pedals are foldable to make the tricycle be compact size.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a tricycle, and more particularly, to a foldable tricycle having two driving units operated by two pedals and the tricycle moves faster by the operation of the driving units. 
       BACKGROUND OF THE INVENTION 
       [0002]    Some tricycles are known to applicant are disclosed in U.S. Pat. No. 6,467,781, U.S. Pat. No. 6,517,093, U.S. Pat. No. 6,554,302 and U.S. Pat. No. 6,851,694. All of the disclosed tricycles include a post connected to the front wheel and two swing links arms respectively connected with two rear wheels. The user stands on two footboards on the swing links and twists his or her body to generate a force to move the tricycle forward. Some tricycles include joints which allow the tricycle to be folded in smaller size which is benefit for carry and transportation. 
         [0003]    The force that moves the tricycle forward is the weight of the user and the torque that the user applies to the tricycle. However, the tricycle is difficult to control its direction because the user has to operate the front wheel left and right repeatedly. In addition, the speed of the conventional tricycles is limited and cannot move faster, the users can easily feel boring. 
         [0004]    The present invention intends to provide a tricycle which is able to move faster then the conventional tricycles. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention relates to a tricycle which comprises a post connected to a front wheel seat and a front wheel is connected to the front wheel seat. A head tube is connected to a top of the front wheel seat and a clamping member is connected to the head tube. Two swing links are connected to the clamping member and two footboards are respectively connected to the two swing links. Two rear wheels are connected to the two footboards. A first folding unit is connected between the post and the front wheel seat. The first folding unit includes a base part, a connection member and a fastening member, wherein the base part is received in the head tube and has an engaging slot defined in a top thereof. The connection member is secured to a lower end of the post by the fastening member and has an insertion which is pivotably connected to the engaging slot. An elongate slot is defined through the connection member and the post is mounted to the connection member, a pin extends through the post and the elongate slot so as to allow the post to move along the elongate slot. The fastening member is mounted to the post to fasten the post to the connection member. 
         [0006]    Two second folding units are respectively connected between the swing links and the clamping members. Each second folding unit includes a fixing bar, a folding member and a pin. The fixing bar is fixed to the clamping member corresponding thereto and includes a horizontal groove and a vertical groove. The folding member is fixed to the swing link and includes a tongue and two blocks on two sides of the tongue. The tongue is engaged with the horizontal groove and the two blocks engaged with the vertical groove. The tongue includes a slide slot and a fixing pin extends through the fixing bar and the slide slot so that the folding member is movable within the horizontal slot. The fixing bar includes a first fix hole which is located in alignment with a second fix hole in the tongue. Another pin extends through the first fix hole and the second fix hole to connect the fixing bar and the folding member. 
         [0007]    Two third folding units are respectively connected between the two footboards and the two swing links. Each third folding unit includes a mounting member and an end member. The mounting member has a pair of clamping arms between which the swing link is securely clamped. A locking device is connected to the pair of clamping arms to securely clamp the swing link. Two lips are located to the mounting member and opposite to the clamping arms. Each lip has a guide slot, an engaging recess defined in a surface of the mounting member and located between the two lips. The end member is fixed to an underside of the footboard and includes a tubular member which includes an annular groove with which the swing link is engaged. A protrusion is located on an outside of the tubular member and a gap is defined between the protrusion and the tubular member. The protrusion includes a notch defined in axially therein and a reception recess is defined through the protrusion. The protrusion is located between the two lips. A lever is located in the notch and has a stub extending from an inside thereof. The stub is removably inserted into the reception recess and a spring is biased between the lever and an inside of the notch. Two pins extend through the guide slots and are connected to the protrusion so that the end member is pivotable about two pins. 
         [0008]    Two driving units are respectively connected between the footboards and the rear wheels. Each driving unit includes a pair of side panels, a pedal and a driving device. The two side panels are connected to the underside of the footboard and extend toward the rear wheel. A pair of frames are connected to an underside of the pedal which is pivotably connected between the side panels by the frames. Two springs are connected between the side panels and the pedal. One of the two frames has a driving arm and a driving member is connected a distal end of the driving arm. The driving device is fixed to one of the side panels and includes a rotary device and a one-way driving device which is co-axially connected with the rotary device. The rotary device includes a transmission gear and a coil spring. The transmission gear is connected with the driving member and a first end of the coil spring is connected to the side panel. A second end of the coil spring is engaged with the transmission gear. The one-way driving device includes a one-way gear and a driving gear. The one-way gear is driven by the rotary device and drives the driving gear in one direction. The rear wheel includes a rear wheel axle which is connected between the two side panels. The rear wheel axle has a passive gear which is engaged with and driven by the driving gear. 
         [0009]    In addition, the present invention provides a third embodiment of the two driving units which are respectively connected between the footboards and the rear wheels. Each driving unit includes a pair of side panels, a pedal and a driving device. The two side panels are connected to the underside of the footboard and extend toward the rear wheel. The pedal is connected to an end of the footboard and pivotably connected to a swing arm. A first gear is connected to the swing arm and a second gear is located between the first gear and the rear wheel. The driving device includes a transmission gear, a one-way gear, a driving member and a spring. The transmission gear and the one-way gear are mounted to a rear wheel axle of the rear wheel. The one-way gear is located between the transmission gear and the rear wheel axle. The one-way gear is driven by the transmission gear and drives the rear wheel axle and the rear wheel to rotate in one direction. The driving member is a chain which has a first end fixed to the side panel that is located close to the first gear and a second end of the driving member is engaged with the first and second gears and the transmission gear and is then connected with the spring which is fixed to the side panel. 
         [0010]    The present invention provides a second embodiment of the two driving units which are respectively connected between the footboards and the rear wheels. Each driving unit includes a support member, a pedal and a driving device. The support frame is connected to an underside to the footboard and the pedal is located on a top of the footboard. A swing arm and a curved rack are connected to a lower end of the pedal. The swing arm is pivotably connected to the support member and a spring is connected between the support frame and the swing arm. The driving device is fixed to the support member and includes a rotary device and a one-way driving device which his co-axially connected to the rotary device. The rotary device includes a transmission gear and a coil spring. The transmission gear is engaged with the curved rack and the coil spring is connected between the support member and the transmission gear. The one-way driving device includes a one-way gear, a driving gear and a driving member. The one-way gear is driven by the rotary device and drives the driving gear and the driving member in one direction. The rear wheel includes a rear wheel axle which is rotatably connected to the support member and the rear wheel axle has a passive gear which is engaged with the driving member and driven by the driving member. 
         [0011]    The primary object of the present invention is to provide a tricycle which includes two driving units cooperated with the two rear wheels and the driving units are operated by repeatedly pressing two pedals on the two footboards so as to accelerate the tricycle. 
         [0012]    The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view to show the tricycle of the present invention; 
           [0014]      FIG. 2  is an exploded view to show the first folding unit of the tricycle of the present invention; 
           [0015]      FIG. 3  is an exploded view to show the suspension unit of the tricycle of the present invention; 
           [0016]      FIG. 4  is an exploded view to show the shock absorbing unit of the tricycle of the present invention; 
           [0017]      FIG. 5  is an exploded view to show the second folding unit of the tricycle of the present invention; 
           [0018]      FIG. 6  is an exploded view to show the third folding unit of the tricycle of the present invention; 
           [0019]      FIG. 7  is an exploded view to show the driving unit of the tricycle of the present invention; 
           [0020]      FIG. 8  is a side view to show the driving unit, the rear wheel and the pedal of the tricycle of the present invention; 
           [0021]      FIG. 9  is a side view to show that the driving unit is activated by pressing the pedal downward to drive the rear wheel of the tricycle of the present invention; 
           [0022]      FIG. 10  is a side view to show that the driving unit is not affected when the pedal bounces upward; 
           [0023]      FIG. 11  is a front view to show that the suspension unit is installed to the tricycle of the present invention; 
           [0024]      FIGS. 12 and 13  are two front views to show that the suspension unit is activated when the two swing links are operated; 
           [0025]      FIG. 14  is a side view to show the shock absorbing unit of the tricycle of the present invention is activated; 
           [0026]      FIG. 15  is a side view to show that the first folding unit is operated to release the post upward; 
           [0027]      FIG. 16  shows that the post is folded toward the swing links; 
           [0028]      FIG. 17  is a top view to show the two pins of the second folding unit are released and the two swing links are pulled away from the post; 
           [0029]      FIG. 18  is a top view to show that the two swing links are pivoted to each other; 
           [0030]      FIG. 19  is a side partial cross sectional view to show that the lever of the third folding unit is pulled outward; 
           [0031]      FIG. 20  shows that the footboard is pulled away from the post; 
           [0032]      FIG. 21  shows that the footboard is pivoted to be parallel to the swing link; 
           [0033]      FIG. 22  is a side view to show that the tricycle of the present invention is folded; 
           [0034]      FIG. 23  is a top view to show that the tricycle of the present invention is folded; 
           [0035]      FIG. 24  is a perspective view to show the tricycle of the present invention, wherein a second embodiment of the driving units are installed; 
           [0036]      FIG. 25  is an exploded view to show the second embodiment of the driving unit of the tricycle of the present invention; 
           [0037]      FIG. 26  is a side view to show that the pedal cooperated with the second embodiment of the driving unit is not yet pressed downward; 
           [0038]      FIG. 27  is a side view to show that the pedal in  FIG. 26  is pressed downward to drive the rear wheel; 
           [0039]      FIG. 28  is a side view to show that the driving unit in  FIG. 27  is not affected when the pedal bounces upward; 
           [0040]      FIG. 29  is a perspective view to show the tricycle of the present invention, wherein a third embodiment of the driving units are installed; 
           [0041]      FIG. 30  is an exploded view to show the third embodiment of the driving unit of the tricycle of the present invention; 
           [0042]      FIG. 31  is a side view to show that the pedal cooperated with the third embodiment of the driving unit is not yet pressed downward; 
           [0043]      FIG. 32  is a side view to show that the pedal in  FIG. 31  is pressed downward to drive the rear wheel, and 
           [0044]      FIG. 33  is a side view to show that the driving unit in  FIG. 32  is not affected when the pedal bounces upward. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0045]    Referring to  FIG. 1 , the tricycle of the present invention can be made by materials such as Iron, Aluminum, Magnesium, Titanium, composite material, carbon iron, glass fibers, plastic, wood or bamboos, the tricycle comprises a post  1  connected to a front wheel seat  14  and a front wheel  141  is connected to the front wheel seat  14 . A head tube  15  is connected to a top of the front wheel seat  14  and a clamping member  16  is connected to the head tube  15 . Two swing links  2  are connected to the clamping member  16  and two footboards  17  are respectively connected to the two swing links  2 . Two rear wheels  18  are connected to the two footboards  17 . As shown in  FIG. 2 , a first folding unit  3  is connected between the post  1  and the front wheel seat  14 . The first folding unit  3  includes a base part  31 , a connection member  32  and a fastening member  33 . The base part  31  is received in the head tube  15  and has an engaging slot  311  defined in a top thereof. The connection member  32  is secured to a lower end of the post I by the fastening member  33  and has an insertion  321  which is pivotably connected to the engaging slot  311 . An elongate slot  322  is defined through the connection member  32  and the head tube  15  is mounted to the connection member  32 . A pin  34  extends through the engaging slot  311  of the base part  31  and the insertion  321  to pivotably connect the connection member  32  to the base part  31 . The post  1  is mounted to the connection member  32  and a pin  100  extends through the post  1  and the elongate slot  322  of the connection member  32 . By this way, the post  1  can be moved relative to the connection member  32  with the pin  100  moving along the elongate slot  322 . 
         [0046]    As shown in  FIG. 3 , a suspension unit  4  is connected between the clamping member  16  and the two swing links  2 . The suspension unit  4  includes a pair of cantilever arms  41  which are pivotably connected to the clamping member  16 . The second folding units  6  are connected between the two cantilever arms  41  and the two swing links  2 . A dome head  42  is located between the two cantilever arms  41  and a transverse link  43  extends through the dome head  42 . Two springs  431  are mounted to two ends of the transverse link  43  and biased between the dome head  42  and the cantilever arms  41 . 
         [0047]    As shown in  FIG. 4 , two shock absorbing units  5  are located on two sides of the front wheel  141  and each shock absorbing unit  5  includes a base member  51 , a rod  52  and a spring  53 . The base member  51  is fixed to a front wheel axle  142  and has an extension tube  511 . The rod  52  extends through the base member  51  and the extension tube  511  from an underside of the base member  51 . The spring  52  is mounted to the extension tube  511 . The rod  52  is fixed to the front wheel seat  14  and the spring  53  is biased between the front wheel seat  14  and the base member  51 . 
         [0048]    As shown in  FIG. 5 , two second folding units  6  are respectively connected between the swing links  2  and the clamping member  16 . Each second folding unit  6  includes a fixing bar  61 , a folding member  62  and a pin  64 , wherein the fixing bar  61  is fixed to the clamping member  16  corresponding thereto and includes a horizontal groove  611  and a vertical groove  612  which perpendicularly communicate with the horizontal groove  611 . The folding member  62  is fixed to the swing link  2  and includes a tongue  621  and two blocks  622  on two sides of the tongue  621 . The tongue  621  is engaged with the horizontal groove  611  and the two blocks  622  are engaged with the vertical groove  612 . The tongue  621  includes a slide slot  623  and a fixing pin  63  extends through the fixing bar  61  and the slide slot  623  so that the folding member  62  is movable within the horizontal slot  611 . The fixing bar  61  includes a first fix hole  613  which is located in alignment with a second fix hole  624  in the tongue  621 . Another pin  64  extends through the first fix hole  613  and the second fix hole  624  to connect the fixing bar  61  and the folding member  62 . 
         [0049]    As shown in  FIG. 6 , two third folding units  7  are respectively connected between the two footboards  17  and the two swing links  2 . Each third folding unit  7  includes a mounting member  71  and an end member  72 , wherein the mounting member  71  has a pair of clamping arms  711  between which the swing link  2  is securely clamped. A locking device  712  is connected to the pair of clamping arms  711  to securely clamp the swing link  2 . Two lips  713  are located to the mounting member  71  and opposite to the clamping arms  711 , wherein each lip  713  has a guide slot  714 . An engaging recess  715  is defined in a surface of the mounting member  71  and located between the two lips  713 . The end member  72  is fixed to an underside of the footboard  17  and includes a tubular member  721  which includes an annular groove with which the swing link  2  is engaged. A protrusion  722  is located on an outside of the tubular member and a gap is defined between the protrusion  722  and the tubular member  721 . The protrusion  722  includes a notch  7221  defined in axially therein and a reception recess  7222  is defined through the protrusion  722 . The protrusion  722  is located between the two lips  713 . A lever  723  is located in the notch  7221  and has a stub  7231  extending from an inside thereof. The stub  7231  is removably inserted into the reception recess  7222  and a spring  7232  is biased between the lever  723  and an inside of the notch  7221 . Two pins  73  extend through the guide slots  714  and are connected to the protrusion  722  so that the end member  72  is pivotable about two pins  73 . 
         [0050]    As shown in  FIGS. 7 and 8 , two driving units  8  are respectively connected between the footboards  17  and the rear wheels  18 . Each driving unit  8  includes a pair of side panels  81 , a pedal  82  and a driving device  83 . The two side panels  82  are connected to the underside of the footboard  17  and extend toward the rear wheel  18 . A pair of frames  811  are connected to an underside of the pedal  82  which is pivotably connected between the side panels  81  by the frames  811 . Two springs  812  are connected between the side panels  81  and the pedal  82 . One of the two frames  811  has a driving arm  813  and a driving member  814  is connected a distal end of the driving arm  813 . The driving member  814  can be a chain or a belt or a steel cable. In this embodiment, the driving member  814  is a chain. The driving device  83  is fixed to one of the side panels  81  and includes a rotary device  831  and a one-way driving device  832  which is co-axially connected with the rotary device  831 . The rotary device  831  includes a transmission gear  8311  and a coil spring  8312 . The transmission gear  8311  is connected with the driving member  814  and a first end of the coil spring  8312  is connected to the side panel  81 . A second end of the coil spring  8312  is engaged with the transmission gear  8311 . The one-way driving device  832  includes a one-way gear  8321  and a driving gear  8322 . The one-way gear  8321  is driven by the rotary device  831  and drives the driving gear  8322  in one direction. The rear wheel  18  includes a rear wheel axle  181  which is connected between the two side panels  81 . The rear wheel axle  181  has a passive gear  182  which is engaged with and driven by the driving gear  8322 . 
         [0051]    As shown in  FIGS. 9 and 10 , the user holds the handles  12  and stands on the two footboards  17 . When the user presses downward the two pedals  82  alternatively, the driving arm  813  of each driving unit  8  is pivoted downward and stretches the spring  812 . The rotary device  831  of the driving unit  8  is then rotated by the driving member  814  which is pulled by the driving arm  813 . The coil spring  8312  drives the transmission gear  8311  which drives the one-way driving device  832 . The one-way gear  8321  and the driving gear  8322  are co-rotated and the driving gear  8322  drives the passive gear  182  of the rear wheel axle  18  such that the rear wheel  18  rotates and move the tricycle forward. When the user releases the pedal  82 , the spring  812  bounces the pedal  82  upward as shown in  FIG. 10  and the driving arm  813  pivots upward. The coil spring  8312  is released to rotate the transmission gear  8311  in opposite direction and the one-way gear  8321  is rotated in opposite direction. Nevertheless, the one-way gear  8321  does not output torque to the driving gear  8322  so that the rear wheel  18  keeps on rotating to move the tricycle forward. 
         [0052]    As shown in  FIGS. 11 to 13 , when the user swings the handles  12  back and forth to move the tricycle, the cantilever arms  41  and the clamping member  16  are rotated in opposite directions. The springs  431  are compressed alternatively and provide a force to return the handles  12 , the cantilever arms  41  and the swing links  2 . Besides, when the front wheel  141  moves on rugged roads, the rods  52  of the shock absorbing unit  5  are lowered as shown in  FIG. 14  and the springs  53  are compressed to absorb the shocks transferred to the tricycle. 
         [0053]    As shown in  FIGS. 15 to 20 , the handles  12  can be removed from the transverse tube  11  on the top of the post  1  and then engaged to the positioning members  13  ( FIG. 1 ) on the post  1 . The fastening member  33  of the first folding unit  3  is then released and the post  1  is pulled upward by moving the pin  100  along the elongate slot  322  of the connection member  32  until joint of the insertion  321  and the engaging slot  311  is exposed. The post  1  can then be pivoted about the fixing pin  34  and toward the swing links  2  as shown in  FIG. 16 . The two pins  64  of the second folding unit  6  are then pulled out from the first and second fix holes  613 ,  624 , and the two swing links  2  are pulled away from the front wheel  141  until the blocks  622  disengage from the vertical groove  612 . The folding members  62  of the two swing links  2  can be pivoted about the fixing pins  63  and tongues  621  are pivoted within the horizontal grooves  611  such that the two swing links  2  are moved toward each other. As shown in  FIGS. 19 to 21 , the locking device  712  of each of the third folding units  7  is first released to release the tubular member  721  and the clamping arm  711 . The lever  723  is then pulled outward to compress the spring  7232  and the stub  7231  is removed from the engaging recess  715  of the mounting member  71 . The footboard  17  is then able to be pulled as shown in  FIG. 20  and the protrusion  722  moves between the two lips  712  of the mounting member  71 . When the tubular member  721  is disengaged from the clamping arm  711  and the swing link  2 , the footboard  17  together with the pedal  82  and the driving unit  8  can be pivoted downward about the pin  73  as shown in  FIGS. 22 and 23 . By the folding actions, the tricycle can be folded to be compact and easily carried and transported. 
         [0054]      FIGS. 24 to 26  show a second embodiment of the driving units of the tricycle, wherein the only difference form the first embodiment is the driving units  9 . 
         [0055]    The two driving units  9  are respectively connected between the footboards  17  and the rear wheels  18 . Each driving unit  9  includes a support member  91 , a pedal  92  and a driving device  93 . The support frame  91  is connected to an underside to the footboard  17  and the pedal  92  is located on a top of the footboard  17 . A swing arm  921  and a curved rack  922  are connected to a lower end of the pedal  92 . The swing arm  921  is pivotably connected to the support member  91  and a spring  911  is connected between the support frame  91  and the swing arm  921 . The driving device  93  is fixed to the support member  91  and includes a rotary device  931  and a one-way driving device  932  which his co-axially connected to the rotary device  931 . The rotary device  931  includes a transmission gear  9311  and a coil spring  9312 . The transmission gear  9311  is engaged with the curved rack  922  and the coil spring  9312  is connected between the support member  91  and the transmission gear  9311 . The one-way driving device  932  includes a one-way gear  9321 , a driving gear  9322  and a driving member  9323 . The one-way gear  9321  is driven by the rotary device  931  and drives the driving gear  9322  and the driving member  9323  in one direction. The rear wheel  18  includes a rear wheel axle  181  which is rotatably connected to the support member  91  and the rear wheel axle  181  has a passive gear  182  which is engaged with the driving member  9323  and driven by the driving member  9323 . 
         [0056]    As shown in  FIGS. 27 and 28 , when the pedals  92  are pressed alternatively, the swing arm  921  swings downward and the spring  911  is stretched, the curved rack  922  drives the transmission gear  9311  and the coil spring  9312  drives the one-way driving device  932 . The one-way gear  9321  and the driving gear  9322  are co-rotated, wherein the one-way gear  9321  drives the passive gear  182  on the rear wheel axle  181  such that the rear wheel  18  rotates to move the tricycle forward. When the pedals  92  are released, the springs  911  bounce the pedals  92  back to their original positions and the curved rack  922  moves upward to release the coil spring  9312  such that the transmission gear  9311  rotates in opposite direction. The one-way gear  9321  is rotated in opposite direction too. Nevertheless, the one-way gear  9321  does not output torque to the driving gear  9322  so that the rear wheel  18  keeps on rotating to move the tricycle forward. 
         [0057]      FIGS. 29 to 31  show a third embodiment of the driving units of the tricycle, wherein the only difference form the first and second embodiment is the driving units  10 . 
         [0058]    The two driving units  10  which are respectively connected between the footboards  17  and the rear wheels  18 . Each driving unit  10  includes a pair of side panels  101 , a pedal  102  and a driving device  103 . The two side panels  101  are connected to the underside of the footboard  17  and extend toward the rear wheel  18 . The pedal  102  is connected to an end of the footboard  17  and pivotably connected to a swing arm  1021 . A first gear  1022  is connected to the swing arm  1021  and a second gear  1023  is located between the first gear  1022  and the rear wheel  18 . The driving device  103  includes a transmission gear  1031 , a one-way gear  1032 , a driving member  1033  and a spring  1034 . The transmission gear  1031  and the one-way gear  1032  are mounted to a rear wheel axle  181  of the rear wheel  18 . The one-way gear  1032  is located between the transmission gear  1031  and the rear wheel axle  181 . The one-way gear  1032  is driven by the transmission gear  1031  and drives the rear wheel axle  181  and the rear wheel  18  to rotate in one direction. The driving member  1033  is a chain which has a first end fixed to the side panel  101  that is located close to the first gear  1022  and a second end of the driving member  1033  is engaged with the first and second gears  1022 ,  1023  and the transmission gear  1031  and is then connected with the spring  1034  which is fixed to the side panel  101 . 
         [0059]    As shown in  FIGS. 32 and 33 , the user holds the handles  12  and stands on the two footboards  17 . When the user presses downward the two pedals  102  alternatively, the swing arm  1021  of each driving unit  10  is pivoted downward and stretches the spring  1034 . The driving member  1033  drives the transmission gear  1031  so that the one-way gear  1032  drives the rear wheel axle  181  to rotate the rear wheel  18  to move the tricycle forward. When the user releases the pedal  102 , the spring  1034  bounces the pedal  102  upward as shown in  FIG. 33  and the driving member  1033  drives the transmission gear  1031  to rotate in opposite direction so that the wing arm  1021  and the pedal  102  move to their original positions. The one-way gear  1032  rotates in opposite direction. Nevertheless, the one-way gear  1032  does not output torque to the rear wheel axle  181  so that the rear wheel  18  keeps on rotating to move the tricycle forward. 
         [0060]    The tricycle can be operated by the conventional way and the tricycle can also be move faster than the conventional tricycle by repeatedly and alternatively to activate the driving units which provide further torque to drive the rear wheels of the tricycle. The tricycle can be folded by activating the first, second and third folding units to be compact and easily carried and transported. 
         [0061]    While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.