Patent Publication Number: US-2023134323-A1

Title: Signal detection device for bicycle pedal

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a bicycle signal measuring device, and more particularly to a pedaling signal detection device that measures the force and motion track of pedaling of a bicycle pedal to provide reference to a rider in doing exercise. 
     2. The Related Arts 
     Recently, cycling is loved by the modem people for doing exercise. However, although cycling is effective for providing an effect of exercise, the rider cannot accurately handle the exercise condition and the application of forces by the left and right feet in doing cycling. 
     Consequently, products of force detection units are available in the market. Such force detection units are operable to detect and analyze the strength of a force that the rider applies to a bicycle pedal and a distribution of force on the bicycle pedal, so that the rider may get aware of related information of exercise for improving his or her pedaling efficiency to achieve bettered exercise effect by the bicycle. 
     However, there is still room for improvement for the known products in respect of structure simplification, assembling easiness, durability, and charging convenience. 
     For example, a structure of a known bicycle pedal generally comprises two major parts, which are a pedal body (which is considered a “stator”) and a rotation spindle (which is considered a “rotor”). A known pedal motion signal detection device is provided for measuring a pressing force signal on the rotation spindle, but a power supply device is arranged on the rotation spindle, one end of the rotation spindle, or extending to an outer end of a crank of the bicycle, making it suffering the following disadvantages: 
     (1) In the known pedal motion signal detection device, where the power supply device is arranged on the rotation spindle, since the rotation spindle is rotating for a full turn of 360 degrees, the battery so arranged on the rotation spindle has to take balance of the centrifugal force generated by the full-turn 360-degree rotation into consideration, and consequently, a cylindrical configuration or a cylindrical form of assembly must be adopted. 
     The structure is thus complicated and the fabrication cost is high. 
     (2) In the known pedal motion signal detection device, where the power supply device is arranged above the rotation spindle, since a gap between the rotation spindle and the pedal body is limited, the capacity of the battery has to be excessively reduced, making it only operable for a very short period of time for each round of charging. 
     (3) In the known pedal motion signal detection device, where the power supply device is arranged above the rotation spindle, in addition to the gap between the rotation spindle and the pedal body being small to thereby limit the size of the battery and thus greatly reduce the capacity of the battery, an extra power connector must be provided for connection with an external power supply for charging, the structure being complicated and service being difficult. 
     (4) In the known pedal motion signal detection device, where the power supply device is arranged at an extended end of the rotation spindle by using an additional connector, the structure is complicated and is limited to the rotation spindle rotor, and the battery capacity is small. 
     (5) In the known pedal motion signal detection device, the pedaling signal detection device is arranged in a center of the rotation spindle and a hollow spindle is used, and this imposes constraints to the size and strength of the rotation spindle, and electrical power must be supplied through a power connection device arranged at one end of the spindle. The power supply structure is complicated, and the cost is high. 
     (6) In the known pedal motion signal detection device, the pedaling signal detection device is arranged in a center of the rotation spindle and a hollow spindle is used. The size of the battery is extremely limited due to being constrained by the gap between the rotation spindle and the pedal body, and the capacity of the battery is extremely small, making the life time of the battery extremely short. 
     (7) In the known pedal motion signal detection device, where the pedaling signal detection device is arranged above the rotation spindle, the supply of electrical power is made through a center of the rotation spindle, and a female part of a power connection device is provided at an open end of the center, and the battery and a specific connector (a male part) are provided to combine with and extend through the rotor and a center of a bicycle crank, making the structure complicated, the quality being hard to control, the cost high, and service difficult. 
     SUMMARY OF THE INVENTION 
     To resolve the problems of the known technology, the purpose of the present invention is to provide a novel pedal motion signal detection device, which provides reference information to a rider in doing exercise, so as to allow the rider to adjust exercise habits during exercise and enhance cycling efficiency. 
     To achieve the above objective, the present invention provides a bicycle pedaling signal detection device, which comprises at least one strain gauge, which is disposed in a strain gauge disposition section defined on the rotation spindle; a control circuit board, which is arranged in the strain gauge disposition section of the rotation spindle and is electrically connected to the at least one strain gauge; an electrical power supply unit, which is received in a receiving space defined in the pedal body to supply electrical power; and an electric brush device, which is disposed in a brush disposition section defined on the rotation spindle and is set at a position between the pedal body and the rotation spindle; wherein the electric brush device is electrically connected, by means of conductive wires, to the control circuit board to supply the electrical power of the electrical power supply unit to the control circuit board, and the electric brush device constantly keeps the electrical power supply unit in electrical connection, via the conductive wires, with the control circuit board both in a condition where the pedal body is rotating relative to the rotation spindle and a condition where the rotation spindle is kept stationary. 
     In the other embodiment of the present invention, a receiving space is defined between a free end of the rotation spindle and an end cap of the pedal body. The electric brush device comprises a slip ring carrying board, of which a surface that faces the free end of the rotation spindle is provided with an anode slip ring and a cathode slip ring that are spaced from each other and are each of a ring-like shape; and a brush carrying board, which is mounted to the free end of the rotation spindle, wherein a surface of the brush carrying board that faces the slip ring carrying board is provided with an anode brush and a cathode brush respectively corresponding to the anode slip ring and the cathode slip ring. The slip ring carrying board and a battery unit are arranged in and supported by a support seat, and the support seat is positioned in the receiving space between the free end of the rotation spindle and the end cap. 
     In another embodiment of the present invention, the electric brush device adopts a spring-biased electric brush device. 
     In a further embodiment of the present invention, the signal detection device adopts a structure of contact pin assembly and a removable battery assembly located between the free end of the rotation spindle and the end cap of the pedal body. The contact pin assembly is provided with an anode contact pin, a cathode contact pin and at least one signal contact pin, spaced from each other and located at the free end of the rotation spindle in the axial direction. The anode contact pin and the cathode contact pin are respectively connected by means of conductive wires to the control circuit board, and the at least one signal contact pin is connected by means of at least one signal transmission wire to the control circuit board. The removable battery assembly is provided with a battery container for accommodating a rechargeable battery unit therein and a contact point circuit board mounted to the battery container. The contact point circuit board is provided with an anode contact point and a cathode contact point connected to the rechargeable battery unit and at least one signal contact point connected to at least one electronic component mounted on the contact point circuit board. The anode contact point, the cathode contact point and the at least one signal contact point of the removable battery assembly are correspondingly contacted to the anode contact pin, the cathode contact pin and the at least one signal contact pin of the contact pin assembly, so that the electrical power of the rechargeable battery unit and at least one electronic signal of the at least one electronic component are supplied to the control circuit board through the removable battery assembly, the contact pin assembly and the conductive wires. 
     Preferably, the contact pin assembly further comprises a vertical supporting plate located at the free end of the rotation spindle for fixing the anode contact pin, the cathode contact pin and the at least one signal contact pin. 
     Preferably, the removable battery assembly further comprises a securing member for securing the contact point circuit board onto the battery container. 
     Preferably, the removable battery assembly further comprises an electricity charging port mounted on the contact point circuit board, so that an electrical power is charged through the electricity charging port to the rechargeable battery unit. 
     Preferably, the signal detection device further comprises an end bearing located between the battery container and the end cap. 
     Preferably, the signal detection device further comprises a first end circuit board arranged in the battery container. 
     Concerning efficacy, the present invention provides breaking concept and innovation, and in addition to improving the drawbacks of the known pedaling signal detection device, the principle of electric brush is applied to the pedal motion detection device to realize innovation of structure, high quality, easy assembly, low cost, extended battery life, easy servicing, and bettered green value for environmental protection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view showing a first embodiment according to the present invention; 
         FIG.  2    is another perspective of the first embodiment according to the present invention; 
         FIG.  3    is an exploded view of the first embodiment according to the present invention, with some part detached therefrom; 
         FIG.  4    is a cross-sectional view taken along line A-A of  FIG.  3   ; 
         FIG.  5    is a perspective view illustrating spatial relationships among constituent components of the first embodiment according to the present invention; 
         FIG.  6    is a side elevational view illustrating spatial relationships among the constituent components of the first embodiment according to the present invention; 
         FIG.  7    is a cross-sectional view taken along line B-B of  FIG.  6   ; 
         FIG.  8    is a cross-sectional view taken along line C-C of  FIG.  6   ; 
         FIG.  9    is a cross-sectional view taken along line D-D of  FIG.  6   ; 
         FIG.  10    is a cross-sectional view showing an electric brush device of another embodiment according to the present invention; 
         FIG.  11    is a circuit diagram of a control circuit according to the present invention; 
         FIG.  12    is a perspective view showing a second embodiment according to the present invention: 
         FIG.  13    is a cross-sectional view taken along line E-E of  FIG.  12   ; 
         FIG.  14    is an exploded view of the second embodiment according to the present invention, illustrating some components detached therefrom; 
         FIG.  15    is another exploded view of the second embodiment according to the present invention, illustrating some components detached therefrom; 
         FIG.  16    is a perspective view showing a third embodiment according to the present invention: 
         FIG.  17    is a cross-sectional view taken along line F-F of  FIG.  16   ; 
         FIG.  18    is an exploded view of the third embodiment according to the present invention, illustrating some components detached therefrom; 
         FIG.  19    is another exploded view of the third embodiment according to the present invention, illustrating some components detached therefrom; 
         FIG.  20    is a perspective view showing a fourth embodiment according to the present invention: 
         FIG.  21    is a cross-sectional view taken along line G-G of  FIG.  20   ; 
         FIG.  22    is an exploded view of the fourth embodiment according to the present invention, illustrating some components detached therefrom; and 
         FIG.  23    is another exploded view of the fourth embodiment according to the present invention, illustrating some components detached therefrom. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS.  1 - 4   , which shows a first embodiment according to the present invention, a bicycle pedal  100  generally comprises a rotation spindle  1  and a pedal body  2 , wherein the rotation spindle  1  has a left end that is connectable to a bicycle pedal link (not shown) and a right end (which is an outer end) is a free end. The pedal body  2  is rotatably mounted, by means of a pair of known bearings  31 ,  32 , to the rotation spindle  1 , and an end cap  20  is mounted to an outer end of the pedal body  2 . Since the pedal body  2  generally maintains at a horizontal position when pedaled by a rider, while the rotation spindle  1  is made rotating relative to the pedal body  2 , the pedal body  2  will be referred to as a “stator” and the rotation spindle  1  will be referred to as a “rotor”. 
     In the arrangement of the present invention, a signal detection device  4  is included to detect a pedaling signal generated by a pedaling operation of the bicycle pedal  100 . The signal detection device  4  comprises at least one strain gauge  41  (four such strain gauges being shown in the drawings as an illustrative example for the embodiment), which is disposed in a strain gauge disposition section S 1  defined by the rotation spindle  1 . A control circuit board  42  is disposed in the strain gauge disposition section S 1  and electrically connected to the at least one strain gauge  41 . 
     A brush disposition section S 2  is arranged adjacent to the strain gauge disposition section S 1  in an axial direction M of the rotation spindle  1 . In the instant embodiment, the first bearing  31  is located between the strain gauge disposition section S 1  and the brush disposition section S 2 . In another embodiment of the present invention, the bearings  31  may be set at other positions on the rotation spindle  1  such that there is no bearing  31  between the strain gauge disposition section S 1  and the brush disposition section S 2 . 
     The pedal body  2  is formed with a receiving space  21  at a location corresponding to the brush disposition section S 2  to receive and hold at least one electrical power supply unit  22 , and is closed and covered by a cover  23  set thereon. At least one electric brush device  5  is arranged in the brush disposition section S 2  between the receiving space  21  of the pedal body  2  and the rotation spindle  1 . 
     Referring to both  FIGS.  5  and  6   , the electric brush device  5  comprises an anode slip ring  51  and a cathode slip ring  52 , which are circumferentially arranged on the brush disposition section S 2  of the rotation spindle  1  in a manner of being spaced from each other. and are respectively and electrically connected by an anode conductive wire  55   a  and a cathode conductive wire  55   b  to the control circuit board  42  located in the strain gauge disposition section S 1 . The conductive wires  55   a ,  55   b  can each be one of a metallic conductive wire and a flexible circuit board. 
     The electric brush device  5  further comprises an anode brush  53  and a cathode brush  54 . The anode brush  53  and the cathode brush  54  each have a fixed end that is fixed by a positioning element  59  to be set in the receiving space  21  of the pedal body  2  and are electrically connected with the electrical power supply unit  22 . The anode brush  53  and the cathode brush  54  each have an opposite end that is extended in a direction toward the brush disposition section S 2  of the rotation spindle  1  to respectively contact the anode slip ring  51  and the cathode slip ring  52 . The anode slip ring  51  and the cathode slip ring  52  are made of graphite, copper, or other metallic conductive materials. 
     The electrical power supply unit  22  has a positive electrode that is electrically connected through the anode brush  53 , the anode slip ring  51 , and the anode conductive wire  55   a  to the control circuit board  42 , and the electrical power supply unit  22  has a negative electrode that is electrically connected through the cathode brush  54 , the cathode slip ring  52 , and the cathode conductive wire  55   b  to the control circuit board  42 . As such, regardless whether the pedal body  2  is rotating relative to the rotation spindle  1  or is kept stationary relative to the rotation spindle  1 , the electric brush device  5  constantly maintains the electrical power supply unit  22  in electrical connection with the control circuit board  42  to keep supplying electrical power to the control circuit board  42 . In addition to the conductive wires  55   a ,  55   b  connecting the control circuit board  42  and the electrical power supply unit  22 , at least one signal wire is electrically connected between the control circuit board  42  and the electrical power supply unit  22  to transmit, when necessary, at least one signal between the control circuit board  42  and the electrical power supply unit  22 . 
     The electric brush device  5  comprises at least one or multiple electric brushes and slip rings that correspond to each other, and at least one circuit component  24  (such as a circuit board, an indicator, and so on) is arranged in the brush disposition section S 2 , so that the control circuit board  42  may be electrically connected, by means of at least one signal wire extending through the bearing  31  and the electric brush device  5 , to the circuit component  24 . 
       FIG.  7    is a cross-sectional view taken along line B-B of  FIG.  6   , showing, in the strain gauge disposition section S 1  of the rotation spindle  1 , strain gauges  41  are arranged on a circumferential surface of the rotation spindle  1  in a manner of being spaced from each other, and the control circuit board  42  is also disposed in the strain gauge disposition section S 1 . 
       FIG.  8    is a cross-sectional view taken along line C-C of  FIG.  6   , showing the rotation spindle  1  is formed, in an outer circumferential surface thereof that corresponds to the bearing  31 , with a groove  11  that extends in the axial direction M of the rotation spindle  1  to allow the conductive wires  55   a ,  55   b  to extend therethrough. 
       FIG.  9    is a cross-sectional view taken along line D-D of  FIG.  6   , showing the anode brush and the cathode brush of the electric brush device  5  are each a reed-based electric brush device. Namely, as shown in the drawing, one end of the anode brush  53  is extended to contact the corresponding anode slip ring  51 . In an actual application, a spring-biased electric brush device can be used. For example,  FIG.  10    shows a spring-biased electric brush device  5   a . Taking the anode or positive electrode as an example, a conductive member  531  is arranged at a location corresponding to the anode slip ring  51 , and a carbon brush  532  and a spring  533  are loaded in the conductive member  531 , so that the spring  533  pushes the carbon brush  532  to contact the anode slip ring  51  thereby realizing electrical connection, this also achieving a similar function. 
       FIG.  11    shows a control circuit  200  arranged on the control circuit board  42  according to the present invention comprises a signal processing unit  71 ; at least one track sensing unit  72 , which detects at least one track signal in a pedaling operation of the bicycle pedal  100 ; a track sensing circuit  73 , which is connected to the at least one track sensing unit  72  to receive the at least one track signal and to transmit the at least one track signal to the signal processing unit  71 ; at least one strain gauge  41 , which detects a plurality of force application signals of the bicycle pedal  100  during the pedaling operation; a pressing force sensing circuit  74 , which is connected to the at least one strain gauge  41  to receive the plurality of force application signals and to transmit the plurality of force application signals to the signal processing unit  71 ; and a wireless transmission module  75 , which is connected to the signal processing unit  71 . 
     In the control circuit, based on the at least one track signal and the plurality of force application signals, the signal processing unit  71  acquires a pedaling signal of spatial angle change during the pedaling operation of the bicycle pedal  100  and a force value applied to the pedal body  2 , which are then transmitted through the wireless transmission module  75  to a receiver device  8 . The pedaling signal and the force value so applied are then displayed on a display  81  of the receiver device  8  for reference by the rider in doing exercise. 
     Referring to  FIGS.  12 - 15   , a structural arrangement of a third embodiment according to the present invention is shown. The constituent components of the instant embodiment are designed with the same reference signs as those of the similar components of the previous embodiment for purposes of correspondence. 
     In the instant embodiment, the bicycle pedal  100   a  comprises a rotation spindle  1  and a pedal body  2 . The pedal body  2  is rotatably mounted, by means of a pair of bearings  31 ,  32 , to the rotation spindle  1 . A signal detection device  4  comprises at least one strain gauge  41  (four such strain gauges being shown in the drawings as an illustrative example for the embodiment) and a control circuit board  42 , which is disposed in a strain gauge disposition section S 1  of the rotation spindle  1 . 
     A spring-biased electric brush device  5   b  is arranged in a receiving space defined between a free end  12  of the rotation spindle  1  and an end cap  20  of the pedal body  2 . 
     The spring-biased electric brush device  5   b  comprises a slip ring carrying board  61 . A surface of the slip ring carrying board  61  that faces the free end  12  of the rotation spindle  1  is provided with an anode slip ring  611  and a cathode slip ring  612  (as shown in  FIG.  15   ) that are of ring-like shapes and spaced from each other. The spring-biased electric brush device  5   b  comprises a spring-biased anode brush  661  and a spring-biased cathode brush  662 , the two being positioned on a surface of a brush carrying board  663  that faces in a direction toward the slip ring carrying board  61  and spaced from each other, and being electrically connected, by means of a pair of conductive wires  55   a ,  55   b  extending through the central axial hole  13  of the rotation spindle  1 , to the control circuit board  42  located in a strain gauge disposition section S 1  defined by the rotation spindle  1 . 
     The brush carrying board  663  is supported in a tubular support seat  664 , in such a way that front ends of the spring-biased anode brush  661  and the spring-biased cathode brush  662  project outside a surface of tubular support seat  664  by a length. As such, the spring-biased anode brush  661  and the spring-biased cathode brush  662  are respectively biased and pushed by internally arranged springs (the structure of the electric brush being similar to what shown in  FIG.  10   ) to have the spring-biased anode brush  661  and the spring-biased cathode brush  662  contacting with the anode slip ring  611  and the cathode slip ring  612  of the slip ring carrying board  61 , respectively. 
     With the slip ring carrying board  61  being mounted to and positioned on the support seat  63 , a conductive board  64  and a battery unit  65  are mounted to an outside surface of the slip ring carrying board  61 , such that the positive electrode of the battery unit  65  is electrically connected to the control circuit board  42  through the conductive board  64 , the anode slip ring  611  of the slip ring carrying board  61 , the anode brush  621  of the brush carrying board  62 , the anode conductive wire  55   a . Besides, the negative electrode of the battery unit  65  is electrically connected to the control circuit board  42  through the conductive tab  613 , the cathode slip ring  612  of the slip ring carrying board  61 , the cathode brush  622  of the brush carrying board  62 , the cathode conductive wire  55   b.    
     Regardless whether the pedal body  2  is rotating relative to the rotation spindle  1  or is kept stationary relative to the rotation spindle  1 , electrical power from the battery unit  65  is kept in electrical connection, through the spring-biased electric brush device  5   b  and a pair of conductive wires  55   a ,  55   b , with the control circuit board  42 . 
     The control circuit  200  shown in  FIG.  11    is equally applicable to the structural arrangement of the second embodiment according to the present invention to detect a pedaling signal of spatial angle change during the pedaling operation of the bicycle pedal and a force value applied to the pedal body, which are then transmitted to a receiver device to allow the pedaling signal and the force value so applied to be displayed by the receiver device for reference by a rider in doing exercise. 
     Referring to  FIGS.  16 - 19   , a structural arrangement of a third embodiment according to the present invention is shown. The constituent components of the instant embodiment are designed with the same reference signs as those of the similar components of the previous embodiments for purposes of correspondence. In the instant embodiment, the bicycle pedal  100   b  similarly comprises the same constituent components as the previous embodiments as described above. 
     The instant embodiment is different from the previous embodiments in that the present invention adopts a structure of contact pin assembly  5   c  and a removable battery assembly  9  between the free end  12  of the rotation spindle  1  and the end cap  20  of the pedal body  2 . 
     The contact pin assembly  5   c  comprises an anode contact pin  56   a , a cathode contact pin  56   b  and at least one signal contact pin spaced from each other and mounted on a vertical supporting plate  14  located at the free end  12  of the rotation spindle  1 , extended toward the end cap  20  in an axial direction. In a preferred embodiment of the present invention, a plurality of signal contact pins  56   c - 56   f  are spaced from each other and mounted on the vertical supporting plate  14  for transferring a plurality of electronic signals. 
     A communication hole  15  is formed in the rotation spindle  1  and communicated between the free end  12  of the rotation spindle  1  and the strain gauge disposition section S 1 . The anode contact pin  56   a  and the cathode contact pin  56   b  are respectively connected, by means of conductive wires  55   a ,  55   b  extending through the communication hole  15  of the rotation spindle  1 , to the control circuit board  42  located in a strain gauge disposition section S 1  defined by the rotation spindle  1 . The signal contact pins  56   c - 56   f  are respectively connected, by means of signal transmission wires  55   c - 55   f  extending through the communication hole  15  of the rotation spindle  1 , to the control circuit board  42 . 
     The removable battery assembly  9  is removably located between the contact pin assembly  5   c  and the end cap  20 . The removable battery assembly  9  includes a battery container  91  for accommodating a rechargeable battery unit  92  therein. A contact point circuit board  93  is secured to a side end of the battery container  91  by means of a securing member  96 . Further, an electricity charging port  94  is mounted on the contact point circuit board  93 , so that an electrical power may be charged through the electricity charging port  94  to the rechargeable battery unit  92 . 
     Optionally, a first end circuit board  911  may be arranged in the battery container  91 , so that relative electronic components such as wireless transmission module, antenna and/or indicator may be mounted on the first end circuit board  911 . Furthermore, an end bearing  33  is located between the battery container  91  and the end cap  20 , so that the first pedal body  2  and the end cap  20  is rotatable about the rotation spindle  1  and the removable battery assembly  9  by mean of the bearings  31 ,  32  and  33  during pedaling. 
     As shown in  FIGS.  18  and  19   , the contact point circuit board  93  that faces the free end  12  of the rotation spindle  1  is provided with an anode contact point  93   a  electrically connected to an anode terminal of the battery unit  92 , a cathode contact point  93   b  electrically connected to a cathode terminal of the battery unit  92  and a plurality of signal contact points  93   c - 93   f  connected to at least one electronic component  95  mounted on the contact point circuit board  93 . 
     Alternatively, the anode contact point  93   a , the cathode contact point  93   b  and the signal contact points  93   c - 93   f  may be made in the form of conductive sockets or conductive through holes for electrically connected to the anode contact pin  56   a , the cathode contact pin  56   b  and the signal contact pins  56   c - 56   f  respectively. 
     When the removable battery assembly  9  is coupled to the free end  12  of the rotation spindle  1 , the anode contact point  93   a , the cathode contact point  93   b  and the signal contact points  93   c - 93   f  of the removable battery assembly  9  are correspondingly contacted to the anode contact pin  56   a , the cathode contact pin  56   b  and the signal contact pins  56   c - 56   f  of the contact pin assembly  5   c , so that the electrical power of the rechargeable battery unit  92  and electronic signals of the electronic component  95  are electrically connected to the control circuit board  42  through the removable battery assembly  9 , the contact pin assembly  5   c  and the conductive wires  55   a ,  55   b  and signal transmission wires  55   c - 55   f  respectively. 
     The battery container  91 , the rechargeable battery unit  92 , the contact point circuit board  93 , the electricity charging port  94 , the first end circuit board  911  and the securing member  96  are assembled as a union unit to form the removable battery assembly  9  adapted to be simply electrically connected to the contact pin assembly  5   c  and then covered by the end cap  20 . The removable battery assembly  9  is also adapted to be removed from the free end  12  of the rotation spindle  1  after the end cap  20  is removed for charging. Preferably, a sealing element  97  is located between the battery container  91  and the end cap  20  for water-proof purpose. 
     Referring to  FIGS.  20 - 23   , a structural arrangement of a fourth embodiment according to the present invention is shown. In the instant embodiment, the bicycle pedal  100   c  similarly comprises the same constituent components as the third embodiments as described above. 
     The instant embodiment adopts a structure of contact pin assembly  5   d  similar to the contact pin assembly  5   c  as the third embodiment. The contact pin assembly  5   d  comprises an anode contact pin  56   a  and a cathode contact pin  56   b  spaced from each other and mounted on a vertical supporting plate  14  located at the free end  12  of the rotation spindle  1 , extended toward the end cap  20  in an axial direction. 
     A central axial hole  13  is formed in the rotation spindle  1  and communicated between a free end  12  and a crank end  16  of the rotation spindle  1 . Further, a second end circuit board  912  is arranged in a space defined at the crank end  16  of the rotation spindle  1 . The anode contact pin  56   a  and the cathode contact pin  56   b  are respectively connected, by means of the anode conductive wire  55   a  and the cathode conductive wire  55   b  extending through the central axial hole  13  of the rotation spindle  1 , to the second end circuit board  912 . 
     Further, a branch pathway  13   a  is formed in the rotation spindle  1  and intercommunicating between the central axial hole  13  and the strain gauge disposition section S 1 , so that a plurality of signal transmission wires  55   c - 55   f  may pass through the central axial hole  13  and the branch pathway  13   a  for connecting the second end circuit board  912  to the control circuit board  42 . 
     The removable battery assembly  9  is removably located between the contact pin assembly  5   d  and the end cap  20 . The removable battery assembly  9  includes a battery container  91  for accommodating a rechargeable battery unit  92  therein. A contact point circuit board  93  is secured to a side end of the battery container  91  by means of a securing member  96 . Further, an electricity charging port  94  is mounted on the contact point circuit board  93 , so that an electrical power may be charged through the electricity charging port  94  to the rechargeable battery unit  92 . 
     Furthermore, an end bearing  33  is located between the battery container  91  and the end cap  20 , so that the first pedal body  2  and the end cap  20  is rotatable about the rotation spindle  1  and the removable battery assembly  9  by mean of the bearings  31 ,  32  and  33  during pedaling. 
     The detailed description provided above is made with reference to feasible embodiments of the present invention. Such embodiments are not intended to limit the scope of the present invention as defined in the appended claims. Equivalent embodiments or variations are considered falling within the scope of the claims.