Abstract:
A bicycle display apparatus comprises a computing component and a separate display component. The computing component is structured for attachment to the bicycle, calculates cumulative information produced from a bicycle-related running condition, and includes an information output for outputting the calculated cumulative information. The display component includes an information input that receives the cumulative information calculated by the computing component, and the display component displays the cumulative information calculated by the computing component.

Description:
BACKGROUND OF INVENTION  
         [0001]    The present invention is directed to bicycles and, more particularly, to a bicycle display apparatus with distributed processing.  
           [0002]    Cycle computers typically calculate and display travel information such as the bicycle velocity, travel distance, total distance, and so on. Such a cycle computer is shown in Japanese Unexamined Patent Application (Kokai) 2000-16367. More specifically, cycle computers typically comprise a display control component having a microcomputer that is operated by power supplied from an internally mounted battery, a liquid crystal display (LCD) component for displaying the travel information, and mode buttons for various types of input and control functions. A conventional rotation sensor comprising a reed switch mounted on the bicycle frame and a magnet mounted on a wheel is operatively coupled with or without wires to the display control component, and the display control component computes the velocity, total distance, or travel distance based on electrical pulses from the rotation sensor.  
           [0003]    Total distance is commonly referred to as distance traveled by the bicycle from the beginning of travel after the display has been mounted on the bicycle (or master reset) until the present, and it may be computed by counting pulses from the rotation sensor since that time. Travel distance is commonly referred to as distance traveled by the bicycle from the point at which a device referred to as a trip meter is reset, and it may be computed by counting pulses from the rotation sensor since the trip meter was reset. The computed total distance and travel distance are stored in a memory inside the microcomputer and selectively displayed as desired by the rider.  
           [0004]    Some cycle computer display control components are designed to be detachable in order to prevent theft and to allow the display control component to be replaced separately without replacing the entire cycle computer. However, that means the total distance or travel distance is not calculated when the display control component is taken off during travel to prevent theft during rest stops or the like and the rider forgets to put the device back on when traveling resumes. In any event, total distance also cannot be carried over to replacement display control components when such components are replaced due to microcomputer malfunctions or the like. As a result, the total distance is not accurately displayed when the display control component is replaced.  
         SUMMARY OF INVENTION  
         [0005]    The present invention is directed to various features of a bicycle display apparatus. In one embodiment, a bicycle display apparatus comprises a computing component and a separate display component. The computing component is structured for attachment to the bicycle, calculates cumulative information produced from a bicycle-related running condition, and includes an information output for outputting the calculated cumulative information. The display component includes an information input that receives the cumulative information calculated by the computing component, and the display component displays the cumulative information calculated by the computing component. Such a structure allows the cumulative information to be properly displayed even when the display component is temporarily detached or replaced. Additional inventive features will become apparent from the description below, and such features alone or in combination with the above features may form the basis of further inventions as recited in the claims and their equivalents. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0006]    [0006]FIG. 1 is a side view of a particular embodiment of a bicycle:  
         [0007]    [0007]FIG. 2 is a more detailed view the handlebar assembly;  
         [0008]    [0008]FIGS. 3 and 4 are schematic block diagrams of a computer control device for components of the bicycle;  
         [0009]    [0009]FIG. 5 is an illustration of items displayed on the computer display;  
         [0010]    [0010]FIG. 6 is a flow chart of a particular embodiment of a main processing routine in a first control unit;  
         [0011]    [0011]FIG. 7 is a flow chart of a particular embodiment of a data processing routine;  
         [0012]    [0012]FIG. 8 is a flow chart of a particular embodiment of a main processing routine in a third control component; and  
         [0013]    [0013]FIG. 9 is a block diagram of a particular embodiment of contents of a memory component. 
     
    
     DETAILED DESCRIPTION  
       [0014]    [0014]FIG. 1 is a side view of a particular embodiment of a bicycle  1 . Bicycle  1  comprises a frame body  2  constructed by welding together tubing having noncircular cross-sections. A front fork  3  is mounted to the front of frame body  2  for rotation around an inclined axis, and a handlebar assembly  4  is mounted to the top of front fork  3 . A saddle  18  is mounted to the upper middle part of frame body  2 , a drive mechanism  5  is mounted to the lower part of frame body  2 , a front wheel  6  is rotatably mounted to the bottom of front fork  3 , and a rear wheel  7  having a hub dynamo  10  is rotatably mounted to the rear of frame body  2 . Hub dynamo  10  houses an alternating current generator  19  (FIG. 3) for generating electricity through rotation of rear wheel  7 . A front transmission  8  including a front derailleur  26   f  is mounted to the lower middle part of frame body  2 , and a rear transmission  9  including a rear derailleur  26   r  is mounted to the rear of frame body  2 . A front suspension  13   f  is mounted to front fork  3 , and a rear suspension  13   r  is mounted between stationary and articulated portions of frame body  2 .  
         [0015]    As shown in FIG. 2, handlebar assembly  4  comprises a handle stem  12  mounted to the top of front fork  3  and a handlebar  15  mounted to the top of handle stem  12 . Brake lever assemblies  16  and grips  17  are mounted at the opposite ends of handlebar  15 . The right side brake lever assembly  16  includes a rear downshift switch  20   a  for manually downshifting rear derailleur  26   r  in single increments, a rear upshift switch  20   b  for manually upshifting rear derailleur  26   r  in single increments, and a mode switch  21   a  for switching between automatic and manual shift modes. The left side brake lever assembly  16  includes a front downshift switch  20   c  for manually downshifting front derailleur  26   f  in single increments, a front upshift switch  20   d  for manually upshifting front derailleur  26   f  in single increments, and a suspension control switch  21   b  for adjusting the stiffness of front suspension  13   f  and rear suspension  13   r .  
         [0016]    As shown in FIG. 1, drive mechanism  5  comprises a crank  27  rotatably mounted at the bottom bracket of frame body  2 , front and rear transmissions  8  and  9 , and a chain  29 . Front transmission  8  comprises, for example, three front sprockets F 1 -F 3  and front derailleur  26 f. Front sprockets F 1 -F 3  are mounted to crank  27 , and front derailleur  26   f  is mounted on frame body  2 . Rear transmission  9  comprises, for example, a multiple sprocket assembly  25  having eight rear sprockets R 1 -R 8  and rear derailleur  26   r . Multiple sprocket assembly  25  is mounted to rear wheel  7  and rear derailleur  26   r  is mounted at the back of frame body  2 . Crank  27  comprises a right crank arm  27   a  and a left crank arm  27   b , wherein front sprockets F 1 -F 3  are mounted to right crank arm  27   a . Chain  29  engages one of the front sprockets F 1 -F 3  and one of the rear sprockets R 1 -R 8 .  
         [0017]    Front sprockets F 1 -F 3  are arranged in the order of an increasing number of teeth, wherein front sprocket Fl is the laterally innermost front sprocket having the least number of teeth, and front sprocket F 3  is the laterally outermost front sprocket having the most number of teeth. Rear sprockets Rl-R 8  are arranged in the order of a decreasing number of teeth, wherein rear sprocket R 1  is the laterally innermost rear sprocket having the most number of teeth, and rear sprocket R 8  is the laterally outermost rear sprocket having the least number of teeth.  
         [0018]    A rotation sensor (not shown in FIG. 1) is provided for sensing the rotation of crank  27 . The presence or absence of rotation of crank  27  ordinarily is used in part to control the operation of front and rear transmissions  8  and  9 . For example, derailleurs cannot shift properly when crank  27  is stationary, so any requested operation of a derailleur may be delayed until crank  27  is rotating. A rotation sensor typically comprises a reed switch  23  (FIG. 3) mounted to frame body  2  and a magnet (not shown) mounted to one of the crank arms  27   a  and  27   b  so that reed switch  23  provides a pulse whenever the magnet passes by.  
         [0019]    A controller  11  (FIG. 3) is provided for controlling various components including the front and rear transmissions  8  and  9  and the front and rear suspensions  13   f  and  13   r . More specifically, controller  11  controls front and rear transmissions  8  and  9  in response to the operation of shift switches  20   a - 20   d  and mode switch  21 a, and it controls front and rear suspensions  13   f  and  13   r  in response to the operation of control switch  21   b . Controller  11  also automatically controls the operation of front and rear transmissions  8  and  9  in response to bicycle velocity.  
         [0020]    As shown in FIGS. 3 and 4, controller  11  comprises a first control unit  30 , a second control unit  31 , and a third control unit  32 . First control unit  30  may be mounted, for example, on the bottom bracket of frame body  2  in proximity to the rotation sensor and front derailleur  26   f , and it is connected to alternating current generator  19 . The electrical current generated by alternating current generator  19  powers first control unit  30 , and first control unit  30  uses the supplied electrical current to control the operation of front derailleur  26   f , rear derailleur  26   r  and rear suspension  13   r . First control unit  30  also supplies control signals (e.g., a velocity signal) superimposed on a relatively low current signal (e.g., pulse code modulated (PCM) signals) to second control unit  31  and third control unit  32 . Since first control unit  30  is disposed on the bottom bracket of frame body  2 , it is fairly close to alternating current generator  19 . As a result, a short power cable may be used to connect first control unit  30  to alternating current generator  19 , and the communication of power between the two may be carried out with high efficiency.  
         [0021]    First control unit  30  controls front transmission  8 , rear transmission  9  and rear suspension  13   r  in accordance with the operating mode set by mode switch  21   a . In this embodiment, in automatic mode, front transmission  8  and rear transmission  9  are controlled according to bicycle velocity, and rear suspension  13   r  may be set in one of two levels (e.g., hard or soft) depending on bicycle velocity. In manual mode, rear transmission  9  is controlled by the operation of shift switches  20   a  and  20   b , front transmission  8  is controlled by the operation of shift switches  20   c  and  20   d , and rear suspension  13   r is controlled by the operation of control switch  21   b.    
         [0022]    First control unit  30  has a first control portion  35  that comprises a computing component in the form of a microcomputer including a CPU, memory, I/O interface, and the like. A number of modules are connected to first control portion  35 . Such modules include a waveform shaping circuit  36  for generating a velocity signal from pulses output from alternating current generator  19 ; a charging control circuit  33 ; a first power storage element  38   a ; a second power storage element  38   b ; the rotation sensor reed switch  23 ; a power supply and communications circuit  34  that switches on and off a relatively low current signal from second power storage element  38   b  to second control unit  31  and third control unit  32  and provides the composite power/control PCM signals mentioned above to second control unit  31  and third control unit  32 ; a power on/off switch  28  that switches on and off a relatively high current signal from first power storage element  38   a  to second control unit  31 ; a front motor driver (FMD)  39   f  for operating a front derailleur motor (FDM)  44   f  for front derailleur  26   f ; a rear motor driver (RMD)  39   r  for operating a rear derailleur motor (RDM)  44   r  for rear derailleur  26   r ; a front operating location sensor (FLS)  41   f  for front derailleur  26   f ; a rear operating location sensor (RLS)  41   r  for rear derailleur  26   r ; a rear suspension driver (RSD)  43   r  for operating rear suspension  13   r ; and a first memory component  47  for storing travel information such as total distance (in which case it functions as a cumulative information memory) and so on. First memory component  47  may comprise a nonvolatile memory such as an EEPROM for retaining the data stored therein even when the power source is interrupted.  
         [0023]    Second control unit  31  controls front suspension  13   f in response to control signals sent by first control unit  30 . More specifically, in automatic mode the hardness of front suspension  13   f  is adjusted depending on bicycle velocity, whereas in manual mode the hardness of front suspension  13   f  is adjusted in response to the operation of control switch  21   b . Second control unit  31  also provides control information from switches  20   a - 20   d ,  21   a  and  21   b  to first control unit  30 . For these functions, second control unit  31  includes a third power storage element  38   c , a front suspension driver (FSD)  43   f  for operating front suspension  13   f , a second control portion  45  such as a computing component in the form of a microcomputer, a first receiver circuit  46  for receiving composite power/control signals from power supply and communications circuit  34  in first control unit  30 , and a buffer  48 . As shown in FIG. 2, second control unit  31  is attached to handlebar  15  of handlebar assembly  4  by means of a bracket  50 , with the components of second control unit  31  housed within bracket  50 .  
         [0024]    Third control unit  32  is housed in a case member  54  detachably installed on second bracket  50 , and it functions primarily as a display component. Third control unit  32  has a liquid crystal display (LCD)  56  that displays travel information such as bicycle velocity, cadence, distance traveled, shift position, suspension status, and other information. Third control unit  32  controls LCD  56  in response to control signals output by first control unit  30 . For that purpose, third control unit  32  also includes a fourth power storage element  38   d , a third control portion  55  such as a computing component in the form of a microcomputer, a voltage stabilizing circuit  57 , a backlight  58  for illuminating display  56 , a second memory component  59 , and a second receiver circuit  61  for receiving composite power/control signals from power supply and communications circuit  34  in first control unit  30 . A mode switch  24  protrudes outward from case member  54  as shown in FIG. 2 and provides signals to third control portion  55  to select the types of information displayed on LCD  56  (in which case mode switch  24  functions as a display switching component). Mode switch  24  also may be used to reset travel distance (i.e., begin calculating travel distance anew) such as by depressing mode switch  24  for a selected time interval (e.g., 3 seconds or longer), and to perform other control functions.  
         [0025]    Second memory component  59  may store travel information such as travel distance, total distance(in such cases it functions as a cumulative information memory), travel time, and so on. In this embodiment, second memory component  59  comprises a nonvolatile memory such as an EEPROM so that the various types of data may be retained even when the power source is interrupted as a result of third control unit  32  being detached from second control unit  31 . As shown in FIG. 9, second memory component  59  may be divided into a total distance (OD) memory area  59   a  for storing total distance OD output from first control portion  35 , a travel distance (TD) memory area  59   b  for storing travel distance TD since reset, a reset total distance (OD 1 ) memory area  59   c  for storing the total distance OD at reset, a velocity (V) memory area  59   d  for storing changes in the time of the velocity V to display average velocity, maximum velocity, or the like, and a data memory area  59   e  for storing other data.  
         [0026]    Returning again to first control unit  30 , second power storage element  38   b  is connected to first power storage element  38   a  through a diode  42 . Diode  42  causes electrical current to flow in one direction only from first power storage element  38   a  to second power storage element  38   b . In other words, diode  42  prevents reverse current flow from second power storage element  38   b  to first power storage element  38   a . In this embodiment, first power storage element  38   a  is employed mainly as a power supply for electrical components with high power consumption and high electrical capacity, such as drivers  39   f ,  39   r ,  43   f  and  43   r , whereas second power storage element  38   b  is employed as a power supply for electrical components having low power consumption and low electrical capacity, such as first control portion  35 , third control portion  55 , and LCD  56 . First and second power storage elements  38   a  and  38   b  may comprise high-capacity capacitors, such as electric double layer capacitors. These capacitors store direct current power output from alternating current generator  19  and rectified by charging control circuit  33 . Of course, instead of capacitors, first and second power storage elements  38   a  and  38   b  could comprise secondary cells, such as nickel-cadmium, lithium ion, or nickel hydrogen cells.  
         [0027]    Charging control circuit  33  comprises a rectifier circuit  37  and a charge on/off switch  40 . Rectifier circuit  37  rectifies current output from alternating current generator  19  to produce DC current, and charge on/off switch  40  switches on and off the current output by the rectifier circuit  37  in response to control signals from first control portion  35 . More specifically, first control portion  35  monitors the voltage of first power storage element  38   a.  Below a predetermined voltage (e.g., 5.5V), first control portion  35  outputs a control signal for switching on the charge on/off switch  40 , thus allowing first power storage element  38   a to charge. On the other hand, if the voltage of first power storage element  38   a  goes above a predetermined voltage (e.g., 7 V), first control portion  35  outputs a control signal for switching off the charge on/off switch  40 , thereby preventing excessive voltage from accumulating in first power storage element  38   a.    
         [0028]    Power on/off switch  28  is connected to first power storage element  38   a  and to first control portion  35 . Power is switched on to activate second control portion  45  and FSD  43   f  when it is necessary to adjust front suspension  13   f , but power is switched off otherwise. As a result, needless power consumption from first power storage element  38   a  can be avoided.  
         [0029]    Power supply and communications circuit  34  is connected to second storage element  38   b  and to first control portion  35 . As noted above, power supply and communications circuit  34  switches on and off a relatively low current signal from second power storage element  38   b  to second control unit  31  and third control unit  32  and provides composite power/control signals to second control unit  31  and third control unit  32 , thus functioning as an information output. It does this through a single communication line  52  to reduce components. Power supply and communications circuit  34  is controlled in response to information such as velocity, distance traveled, current transmission gear, automatic vs. manual modes, suspension hardness and the like.  
         [0030]    As shown in FIG. 4, first receiver circuit  46  in second control unit  31  is connected to power supply and communication circuit  34  through communication line  52 , thus functioning as an information input. First receiver circuit  46  extracts the control signals from the composite power/control signals from power supply and communication circuit  34  and communicates the control signals to second control portion  45 . Third power storage element  38   c  also is connected to power supply and communications circuit  34 . Third power storage element  38   c  may comprise, for example, a relatively high capacity capacitor such as an electrolytic capacitor, and it is provided to smooth the electrical current from the composite power/control signals received from power supply and communications circuit  34 . Third power storage element  38   c  provides operating power to buffer  48  that functions to stabilize the analog voltage signals from shift switches  20   a - 20   db  and control switches  21   a  and  21   b.    
         [0031]    Second receiver circuit  61  and fourth power storage element  38   d  in third control unit  32  also are connected to power supply and communication circuit  34  (in parallel with first receiver circuit  46 ). Second receiver circuit  61  extracts the control signals from the composite power/control signals from power supply and communication circuit  34 , thus functioning as an information input, and communicates the control signals to third control portion  55 . Fourth power storage element  38   d  may comprise an electrolytic capacitor that provides operating power directly to third control portion  55  and indirectly to backlight  58  through voltage stabilizing circuit  57 . Voltage stabilizing circuit  57  stabilizes the voltage from fourth power storage element  38   d  to avoid flickering of backlight  58  that otherwise may be caused by the pulsed control signals superimposed on the power signals from power supply and communications circuit  34 .  
         [0032]    [0032]FIG. 5 illustrates an embodiment of information that may be shown on a display screen  71  of LCD  56 . In this embodiment, display screen  71  comprises a main number display portion  72 , an auxiliary number display portion  73 , a description display portion  74 , a rear gear position display portion  75 , and a front gear position display portion  76 . Information such as bicycle velocity, time, etc. is displayed in numerical format in main number display portion  72  and auxiliary number display portion  73 . Description display portion  74  displays a description of the contents of main number display portion  72  and auxiliary number display portion  73 , as well as showing the transmission operating mode. For example, “VEL” indicates travel velocity, “DST” indicates distance traveled, “CLK” indicates current time, “TIM” indicates travel time, an “GEA” indicates current shift position of the front and rear transmissions, “AT” indicates automatic shift mode, “MT” indicates manual shift mode, and so on. The unit of velocity can be switched between “Km/h” and “Mile/h”, and the unit of distance can be switched between “Km” and “Mile.” 
         [0033]    The rear gear position display portion  75  shows the gear position of the rear transmission  9 , and it comprises a plurality of (e.g., nine) elliptical display symbols gradually decreasing in diameter from left to right to correspond with the size of the actual rear sprockets R 1 -R 8 . When initializing LCD  56 , the number of sprockets for rear transmission  9  can be set to match the actual number of sprockets installed on the bicycle. For example, when rear transmission  9  has eight sprockets, as in this embodiment, the number of rear sprockets is input to the cycle computer. Thereafter, eight elliptical display symbols are displayed from left to right in rear gear position display portion  75 , with the one remaining symbol at the right end not displayed. Similarly, the front gear position display portion  76  shows the gear position of the front transmission  8 , and it comprises a plurality of (e.g., three) elliptical display symbols gradually increasing in diameter from left to right to correspond with the size of the actual front sprockets F 1 -F 3 . When initializing LCD  56 , the number of sprockets for front transmission  8  can be set to match the actual number of sprockets installed on the bicycle. For example, when front transmission  8  has two sprockets, the number of front sprockets is input to the cycle computer. Thereafter, two elliptical display symbols are displayed from right to left in front gear position display portion  76 , with the one remaining symbol at the left end not displayed. As a result of this arrangement, the sprocket positions of front and rear transmissions  8  and  9  may be ascertained intuitively at a glance.  
         [0034]    In operation, the alternating current generator  19  of hub dynamo  10  generates electricity as the bicycle is pedaled, and this electricity is supplied to first control unit  30 , with power being stored by first and second power storage elements  38   a  and  38   b . Since alternating current generator  19  is disposed on rear wheel  7 , first and second power storage elements  38   a  and  38   b  can be charged simply by turning the pedals, with the bicycle remaining stationary, by lifting the rear wheel. Thus, it is a simple matter to at least partially charge first and second power storage elements  38   a  and  38   b  by turning the pedals to allow setting up of the electronically operated transmissions and the information displayed on LCD  56 .  
         [0035]    In automatic shift mode, derailleurs  26   f  and  26   r  and suspensions  13   f  and  13   r  are controlled according to a velocity signal generated by first control portion  35  from the shaped pulse output by waveform shaping circuit  36 . More specifically, a shift operation is performed when the bicycle velocity is greater or less than predetermined values, wherein rear derailleur  26   r  is given preference in ordinary shift operations. Also, when velocity goes above a predetermined value, the hardness of the suspensions  13   f  and  13   r  is increased. Meanwhile, first control portion  35  calculates total distance OD from the shaped pulse output by waveform shaping circuit  36  and stores the result in first memory component  47 . Total distance OD may be calculated by counting the shaped pulses, dividing the sum by the number of pulses per wheel rotation, and multiplying the quotient by the wheel circumference. Other cumulative information may be calculated as appropriate.  
         [0036]    Control signals based on information such as velocity, distance, transmission gear, automatic vs. manual modes, suspension hardness, and the like, are generated by first control portion  35  and output to power supply communications circuit  34 . Power supply and communications circuit  34  superimposes the control signals on a power signal derived from second power storage element  38   b  to produce the appropriate PCM signals. The composite power/control signals are then communicated to second control portion  45  and third control portion  55 , whereupon the composite power/control signals are decoded.  
         [0037]    Second control portion  45  is powered by power signals received from power on/off switch  28  and outputs to RSD  43   f  signals for controlling front suspension  13   f  in response to the control signal portion of the composite power/control signals received from power supply and communications circuit  34 . The power signal portion of the composite power/control signals received from power supply and communications circuit  34  powers buffer amp  48 . When a control switch  21   a  or  21   b  or a shift switch  20   a - 20   d  is operated, a signal of different analog voltage is output to first control portion  35  via buffer amp  48 , and first control portion  35  generates the appropriate control signals for controlling one or more of derailleurs  26   f  and  26   r  or suspensions  13   f  and  13   r , or for changing the transmission operating mode.  
         [0038]    Third control portion  55  is powered by the power signal portion of the composite power/control signals received from power supply and communications circuit  34 . Third control portion  55  performs distance calculations and the like based on the control signal portion of the composite power/control signals received from power supply and communications circuit  34  and thereafter outputs to LCD  56  velocity and other kinds of information.  
         [0039]    When driving a motor-driven electrical component having large electrical capacity, such as derailleurs  26   f  and  26   r  or suspensions  13   f  and  13   r , there is a voltage drop in first power storage element  38   a . If first control portion  35 , third control portion  55  and LCD  56  were powered by first power storage element  38   a , the voltage drop could cause the microprocessors and other electronics to reset or cause some other problem. Since the power for these components in this embodiment is provided from second power storage element  38   b connected to first power storage element  38   a  through diode  42 , the components are unaffected by voltage drops in first power storage element  38   a . While second control portion  45  is powered by first power storage element  38   a , it is normally off except when needed to control front suspension  13   f . Consequently, second control portion  45  is unaffected by voltage drops in first power storage element  38   a.    
         [0040]    More specific operations of first control unit  30  and third control unit  32  now will be described with reference to FIGS. 6-8. FIG. 6 is a flow chart of a particular embodiment of a main processing routine in first control unit  30 . When rear wheel  7  turns, alternating current generator  19  supplies electrical power to first control unit  30 , and this power is stored in first power storage element  38   a  and second power storage element  38   b . The power stored in second power storage element  38   b  is supplied to first control portion  35 , and initialization of first control portion  35  is carried out in Step S 1  of FIG. 6. In this initialization process, the transmission operating mode may be set to automatic shift mode, for example.  
         [0041]    In Step S 2 , a timer that measures the processing time per microcomputer processing cycle is started. In Step S 3 , a data processing routine shown in FIG. 7 is performed for computing total distance and the like. In Step S 4 , a shift control process (automatic or manual) is executed in a manner described above. In Step S 5 , another process such as the establishment of the operating mode is executed. In Step S 6 , the process waits for the started timer to stop. When that occurs, the routine returns to Step S 2 .  
         [0042]    [0042]FIG. 7 is a flow chart of a particular embodiment of the data processing routine. It is first determined in Step S 10  whether or not a pulse from the waveform shaping circuit  36  has been received. If so, a pulse count is incremented in Step S 13 , total distance OD is computed from the pulse count as described above in Step S 14 , the computed total distance OD is stored as the most recent total distance in first memory component  47  in Step S 15 , velocity data V is computed from the pulses output by waveform shaping circuit  36  in Step S 16 , and the computed velocity data V is stored in first memory component  47  in Step S 17 . Storing these values allows the most recent data to be output despite differences between computation timing and output timing.  
         [0043]    In any event, it is then determined in Step S 11  whether or not shift position data SH from the operating position sensors  41   r  and/or  41   f  has been received. If so, the data is converted to shift position data SH for display and is stored in first memory component  47  in Step S 18 . Thereafter, the total distance OD, velocity data V, shift position data SH and the like are output through communication line  52  to third control unit  32  for display.  
         [0044]    [0044]FIG. 8 is a flow chart of a particular embodiment of a main processing routine in third control unit  32 . When power is supplied from second storage element  38 b through communication line  52 , third control portion  55  in third control unit  32  performs initialization in Step S 20 . In this initialization process, the units for distance or velocity may be set, for example. In Step S 21 , a timer that measures the processing time per microcomputer processing cycle of the third control portion  55  is started. In Step S 22 , a display process is performed to display velocity, distance, front and rear shift positions, and other data as appropriate. In this embodiment, either travel distance TD or total distance OD is selected for display on the auxiliary number display portion  73  in response to the operation of mode switch  24 , thus allowing the display area to be more compact.  
         [0045]    It is then determined in Step S 23  whether or not velocity V or total distance OD data has been received from first control portion  35  through communication line  52 . If so, the received total distance OD is stored in the total distance OD memory area  59   a  of second memory component  59  in Step S 27 . Then, in Step S 28 , the reset total distance OD 1  stored in the reset total distance OD 1  memory area  59   c  is subtracted from the stored total distance OD to compute the travel distance TD, and the travel distance is then stored in the travel distance TD memory area  59   b  of second memory component  59 . The total distance OD or travel distance TD is displayed at the next occurrence of the display process in Step S 22 .  
         [0046]    In any event, it is determined in Step S 24  whether or not mode switch  24  has been pressed for a long time (thereby functioning as a start input component). If so, the travel distance TD stored in the travel distance TD memory area  59   b  is reset to 0 in Step S 29 , and the current total distance OD is stored as the reset total distance OD 1  in the reset total distance OD 1  memory area  59   c , in which case reset total distance OD 1  functions as reference cumulative information and reset total distance OD 1  memory area  59   c  functions as a reference information memory. Storing the reset total distance OD 1  as reference cumulative information allows the travel distance TD to be accurately calculated from a subsequently received total distance OD even when the power source is interrupted, such as when third control unit  32  is detached from second control unit  31 .  
         [0047]    In any event, another process such as one triggered by a normal operation of mode switch  24  is executed in Step S 25 . Then, the process waits in Step S 26  for the timer started in Step S 21  to stop. When that occurs, the routine returns to Step S 21 .  
         [0048]    It should be readily apparent that the total distance OD is constantly computed by first control portion  35  of first control unit  30 , which tends to be more permanently mounted on the bicycle, and the computed total distance OD is displayed on LCD  56  in third control unit  32 . In other words, the total distance OD is not computed by third control unit  32  at the display end of the cycle computer, but is computed by first control unit  30 , which is separate from the display end. As such, the total distance OD can be properly displayed even when third control unit  32  is replaced. Furthermore, when a plurality of bicycles are owned, the total distances of each of the several bikes can be properly displayed with just one third control unit  32 . The total distance also can be properly displayed when third control unit  32  is mounted, regardless of whether or not it was temporarily detached.  
         [0049]    While the above is a description of various embodiments of inventive features, further modifications may be employed without departing from the spirit and scope of the present invention. For example, in the above embodiment, first control unit  30  computed the total distance, and the total distance was output to third control unit  32 . Alternatively, total distance could be calculated by another component, such as second control unit  31  or some other control unit to which third control unit  32  could be attached.  
         [0050]    In the above embodiment, wheel rotation information was used to calculate velocity and distance, but such data also could be calculated from rotation information from the pulley of the rear derailleur  26 r or crank  27 . If so, wheel rotation information could be derived from this information plus shift position information.  
         [0051]    In the above embodiment, bicycle velocity was derived from signals produced by alternating current generator  19 , which obviates the need for a dedicated rotation information output component. The use of alternating current generator  19  in this manner also allows a plurality of signals to be obtained per revolution of the wheel which, in turn, produces a more precise computation of total distance. However, bicycle velocity could be derived from signals produced by conventional velocity sensors comprising a reed switch and one or more magnets that detect wheel rotation.  
         [0052]    In the above embodiment, the travel distance from a starting point was computed, but the remaining travel distance also may be computed and displayed when the travel distance is known in advance such as during training or touring. Such cases may include a reference information input component (such as mode switch  24 ) for inputting reference information such as a target travel distance; and a remaining distance computation component (such as third control portion  55 ) for computing the remaining travel distance by subtracting the computed travel distance from the input target travel distance. For example, a step for inputting the target travel distance can be inserted after the display process in Step S 22 , the travel distance TD can be computed in Step S 28  for each signal received in Step S 23 , and the computed travel distance TD then can be subtracted from the input target travel distance to compute the remaining travel distance. The remaining travel distance or the target travel distance also may be reset in Step S 29  in the same manner as for the travel distance TD.  
         [0053]    In the above embodiment, first control unit  30 , second control unit  31  and third control unit  32  were operatively coupled by wiring them together, but any of them may be operatively coupled by a wireless communication arrangement.  
         [0054]    The size, shape, location or orientation of the various components may be changed as desired. Components that are shown directly connected or contacting each other may have intermediate structures disposed between them. The functions of one element may be performed by two, and vice versa. The structures and functions of one embodiment may be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature that is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the scope of the invention should not be limited by the specific structures disclosed or the apparent initial focus or emphasis on a particular structure or feature.