Abstract:
A bicycle derailleur gearshift position indicator includes a housing holding a gearshift position indication member, the gearshift position indication member having indication plates corresponding to the gearshift positions of the derailleur system of the bicycle and a view window through which the bicycle rider views the indication of the gearshift position indication member, and a cable take-up wheel suspended below the housing and rotated with the shifters of the derailleur system to move the indication plates of the gearshift position indication member.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to bicycles and, more specifically, to a bicycle derailleur gearshift position indicator. 
     A derailleur is a multiple-speed gear mechanism on a bicycle that involves the moving of the chain from one sprocket to another. Conventional bicycle derailleur systems have no indicator means to indicate the gearshift position. Therefore, the bicycle rider can only judge the current gearshift position by experience subject to the resisting force received from the pedals. This gearshift position judging method is less reliable. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a bicycle derailleur gearshift position indicator, which automatically indicates the gearshift position of the derailleur system when the rider of the bicycle operates the derailleur system. A bicycle derailleur gearshift position indicator according to the present invention comprises a cable take-up wheel rotated with the derailleur cable of the derailleur system of a bicycle subject to the gearshift position of the derailleur system, the cable take-up wheel comprising a recessed receiving portion and a push wall disposed in the recessed receiving portion; a gearshift position indication member, the gearshift position indication member comprising a plurality of indication plates arranged in parallel corresponding to the number of gearshift positions of the derailleur system of the bicycle, the indication plates each having a bottom protruded block respectively supported in the recessed receiving portion of the cable take-up wheel and a top indication face; and a housing, the housing comprising a receiving chamber, which receives the gearshift position indication member, and a view window through which the rider of the bicycle views the indication face of the indication plates of the gearshift position indication member. When the cable take-up wheel is rotated upon operation of the derailleur system by the rider of the bicycle, the push wall of the cable take-up wheel is moved with the cable take-up wheel to push the indication plates of the gearshift position indication member one after another, enabling the rider of the bicycle to view the position change of the indication plates indicative of the position change of the gearshift position of the derailleur system of the bicycle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of a bicycle derailleur gearshift position indicator according to the present invention. 
     FIG. 2 is an exploded view of the bicycle derailleur gearshift position indicator according to the present invention. 
     FIG. 3 is a sectional view taken along line III—III of FIG.  1 . 
     FIG. 4 is a sectional view in an enlarged scale taken along line IV—IV of FIG.  2 . 
     FIG. 5 shows the status of the gearshift position indication member before the operation of the bicycle derailleur system according to the present invention. 
     FIG. 6 shows a position change status of the gearshift position indication member upon an operation of the bicycle derailleur system according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. from  1  through  3 , a bicycle derailleur gearshift position indicator is used in a bicycle and adapted to indicate the engagement position between the drive chain and the gears of the derailleur, comprised of a cable take-up wheel  10 , a gearshift position indication member  20 , and a housing  30 . 
     The cable take-up wheel  10  comprises a pivot hole  11 , which is coupled to a pivot on the shell of the derailleur system (not shown) for enabling the cable take-up wheel  10  to be turned about the pivot subject to the operation of the shifters (not shown), a top sidewall  12 , a recessed receiving portion  13  at the top sidewall  12 , a sloping push wall  14  obliquely upwardly extended from one end of the recessed receiving portion  13  (see also FIG.  4 ). 
     The gearshift position indication member  20  comprises a base panel  22  and a plurality of indication plates  21 . The base panel  22  comprises an oblong locating hole  221 . The indication plates  21  are narrow, elongated, springy, substantially L-shaped plates arranged in parallel, each having a bottom end respectively connected to the base plate  21  and a top end terminating in an indication face  23  marked with a respective numerical sign (1, 2, 3 . . . ) for indicating different gearshift positions. The indication face  23  of each indication plate  21  may be colored with a respective particular color for indication. Further, each indication plate  21  has a protruded block  24  at the bottom side. 
     The housing  30  is a part of the derailleur system disposed above the top side of the cable take-up wheel  10 , comprised of a top cover shell  31 , a bottom cover shell  32 , and a transparent shield  33 . The top cover shell  31  and the bottom cover shell  32  are fixedly fastened together, defining a receiving chamber  34 , which receives the gearshift position indication member  20 . The top cover shell  31  is an opaque member comprises a cover base  312 , a locating block  314  downwardly extended from the cover base  312 , and an extension cover wall  311  obliquely upwardly extended from the periphery of the cover base  312  at one side. The extension cover wall  311  has an elongated front opening  313 . 
     The bottom cover shell  32  comprises a base panel  321 , an extension cover wall  322  obliquely upwardly extended from the periphery of the base panel  321  at one side, an oblong locating hole  323  and an arched slot  324  disposed through the base panel  321 , a stop block  325  disposed at the top side of the extension cover wall  322 , and two pin holders  326  disposed at two sides of the stop block  325 . 
     When covering the top cover shell  31  on the bottom cover shell  322 , the base panel  22  of the gearshift position indication member  20  is supported on the base panel  321  of the bottom cover shell  32  with the protruded blocks  24  of the indication plates  21  respectively engaged into the arched slot  324  of the base panel  321  of the bottom cover shell  32  and the recessed receiving portion  13  of the cable take-up wheel  10 , and the locating block  314  of the top cover shell  31  is plugged into the oblong locating hole  221  of the gearshift position indication member  20  and the oblong locating hole  323  of the bottom cover shell  32  to hold down the gearshift position indication member  20 , preventing the gearshift position indication member  20  from rotation. When assembled, the indication face  23  of each indication plate  21  of the gearshift position indication member  20  is respectively supported on the stop block  325  of the bottom cover shell  32 . 
     The transparent shield  33  is supported between the extension cover wall  311  of the top cover shell  31  and the extension cover wall  322  of the bottom cover shell  32  and covered over the front opening  313  of the top cover shell  31  to use as a view window, having two through holes  331  disposed at two distal ends thereof and respectively connected to the pin holes  326  of the bottom cover shell  32  by a respective pin (not shown). 
     Referring to FIG. 5, when the derailleur of the bicycle does no work, the protruded blocks  24  of the indication plates  21  of the gearshift indication member  20  are received in the recessed receiving portion  13  of the cable take-up wheel  10  and supported on the stop block  325  of the bottom cover shell  32 . At this time, the bicycle rider can see the indication face  23  of every indication plate  21  through the transparent shield  33 . 
     Referring to FIG. 6, when the bicycle rider operates the shifters to change the gearshift position during riding, the cable take-up wheel  10  is rotated with the shifters, and the sloping push wall  14  is moved with the cable take-up wheel  10  to push the protruded block  24  of each indication plate  21  from the recessed receiving portion  13  to the higher top sidewall  12 , and thus the indication face  23  of each indication plate  21  been pushed by the sloping push wall  14  is moved to the inside of the extension cover wall  311  of the top cover shell  31  and kept from sight. On the contrary, when the bicycle rider reverses the shifters, the cable take-up wheel  10  is rotated in the reversed direction, enabling every pushed indication plate  21  to return to its former position by means of the effect of its material springy power. Therefore, a respective indication is viewed through the transparent shield  33  when the bicycle rider changes the gearshift position during riding. 
     While only one embodiment of the present invention has been shown and described, it will be understood that various modifications and changes could be made thereunto without departing from the spirit and scope of the invention disclosed.