Abstract:
A cable operated bicycle shift control device has an outer casing with a cable receiving bore and an access opening for accessing a cable operated winding mechanism to perform maintenance such as replacement of the cable. The cable operated winding mechanism is disposed in the outer casing such that its cable attachment point is disposed relative to the access opening to be accessible from the access opening. A maintenance cover movably is coupled to the outer casing between a closed position overlying the access opening and an open position exposing the access opening.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention generally relates to a bicycle shift control device. More specifically, the present invention relates a cable operated bicycle shift control device that has an access opening for accessing the interior of the bicycle shift control device to perform maintenance.  
           [0003]    2. Background Information  
           [0004]    Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle.  
           [0005]    For example, the front and rear shift control devices are often redesigned to make them easier to operate and easier to maintain. The shift control devices are coupled to a drive train having several gears, which are used on a bicycle in order to climb hills more easily, or to ride faster on flat ground. The shift control devices are each generally coupled to a shift mechanism such as a derailleur or an internally geared hub that is operated by a control cable.  
           [0006]    There are many types of cable operated shift control devices currently being installed on bicycles. For example, some cable operated shift control devices have a pair of shift levers and a cable winding mechanism that rotates via a ratchet mechanism. With conventional cable operated shift control devices of this type, operation of one of the shift lever causes the cable winder to rotate via the ratchet mechanism in one direction by one gear. As a result, the cable is wound around the cable winder, and a shift is made by the shift mechanism from one gear to the next gear. Operation of the other shift lever causes the ratchet mechanism to be released and the cable winder to rotate in the other direction by one gear. As a result, the cable that was wound on the cable winder is played out, and a shift is made in the opposite direction by the shift mechanism.  
           [0007]    Another example of a cable operated shift control device is a hand grip actuated shifter in which the hand grip rotates around the axis of the handlebar to rotate a cable take-up element. Thus, when the hand grip is rotated in one direction, the cable is wound around the take-up element to cause the derailleur or internal geared hub to shift from one gear to the next gear. Rotation of the hand grip in the other direction causes the cable to be unwound or played out so that the derailleur or internal geared hub shifts from one gear to the next gear.  
           [0008]    One problem with these types of cable operated shift control devices is that the control cable sometimes breaks. Many of these shift control device have to be completely disassembled in order to replace the control cable. More recently, a maintenance hole has been provided for changing these control cables. These maintenance holes can allow dirt or other contaminants to enter the unit. Therefore, many control devices with maintenance holes have a plug for covering the hole. These plugs are typically separate parts that are prone to being lost. Moreover, often these plugs are difficult to remove without a tool.  
           [0009]    In view of the above, there exists a need for an improved bicycle shift control device which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.  
         SUMMARY OF THE INVENTION  
         [0010]    One object of the present invention is to provide a bicycle shift control device with an access opening having a slideably maintenance cover for easy access to change the control cable.  
           [0011]    The foregoing object can basically be attained by providing a cable operated bicycle shift control device that has an outer casing with a cable receiving bore and an access opening for accessing a cable operated winding mechanism to perform maintenance such as replacement of the cable. The cable operated winding mechanism is disposed in the outer casing such that its cable attachment point is disposed relative to the access opening to be accessible from the access opening. A maintenance cover slideably is coupled to the outer casing between a closed position overlying the access opening and an open position exposing the access opening.  
           [0012]    These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    Referring now to the attached drawings which form a part of this original disclosure:  
         [0014]    [0014]FIG. 1 is a side elevational view of a conventional bicycle with a bicycle shift control device coupled thereto in accordance with one embodiment of the present invention;  
         [0015]    [0015]FIG. 2 is a perspective view of the shift control device in accordance with the present invention;  
         [0016]    [0016]FIG. 3 is a top plan view of the shift control device in accordance with the embodiment illustrated in FIG. 2;  
         [0017]    [0017]FIG. 4 is a bottom plan view of the shift control device in accordance with the embodiment illustrated in FIGS. 2 and 3;  
         [0018]    [0018]FIG. 5 is an exploded perspective view of the shift control device in accordance with the embodiment illustrated in FIGS.  2 - 4 ;  
         [0019]    [0019]FIG. 6 is a partial side elevational view of the shift control device illustrated in FIGS.  2 - 5  with the maintenance cover in the closed position covering the access opening;  
         [0020]    [0020]FIG. 7 is a partial side elevational view of the shift control device illustrated in FIGS.  2 - 5  with the maintenance cover in the open position exposing the access opening;  
         [0021]    [0021]FIG. 8 is a partial top plan view of the shift control device illustrated in FIGS.  2 - 5  with the maintenance cover in the closed position covering the access opening;  
         [0022]    [0022]FIG. 9 is a partial top plan view of the shift control device illustrated in FIGS.  2 - 5  with the maintenance cover in the open position exposing the access opening; and  
         [0023]    [0023]FIG. 10 is a cross sectional view of the shift control device illustrated in FIGS.  2 - 9  as seen along section line  10 - 10  of FIG. 7.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    Referring initially to FIGS. 1 and 2, a conventional bicycle  10  is illustrated having a shift control device  12  coupled to the handlebar  13  of the bicycle  10  in accordance with one embodiment of the present invention. Bicycles and their various components are well known in the prior art, and thus, the bicycle  10  and its various components will not be discussed or illustrated in detail herein, except for the components that relate to the present invention. In other words, only the shift control device  12  and the components that relate thereto will be discussed and/or illustrated herein.  
         [0025]    In the illustrated embodiment, as best seen in FIGS.  2 - 5 , the shift control device  12  is part of an integrated shifting and braking unit. In other words, the shift control device  12  is fixedly coupled to a lever bracket  14  that pivotally supports a brake lever  16 . Of course, it will be apparent to those skilled in the art from this disclosure that the shift control device  12  could be a separate unit from the brake lever  16 . Moreover, it will be apparent to those skilled in the art from this disclosure that this invention could be utilized with other types of shift control devices such as a hand grip actuated shift control device.  
         [0026]    The shift control device  12  basically includes an outer casing  18  having a cable operated winding mechanism  20  disposed in the outer casing  18 , a pair of shift levers  22  and  24 , and a gear indicator  26  operatively coupled to the cable operated winding mechanism  20 .  
         [0027]    The cable operated winding mechanism  20  and the gear indicator  26  are well known in the art. Thus, these parts will not be discussed or illustrated in detail herein. Moreover, it will be apparent to those skilled in the art from this disclosure that the precise structure of these parts is not crucial to the present invention. The illustrated embodiments of the cable operated winding mechanism  20  and the gear indicator  26  are disclosed in U.S. Pat. No. 5,701,786, assigned to Shimano Inc.  
         [0028]    In the illustrated embodiment, the outer casing  18  is formed of four portions, i.e., a first or upper casing half  30  and a second or lower casing half  32  having a first lower casing portion  32   a,  a second lower casing portion  32   b  and a third lower casing portion  32   c.  The lower casing portions  32   a - 32   c  are fastened to the upper casing half  30  by a bolt  34  extending through the outer casing  18  and a nut  36  attached to an upper portion of the upper casing half  30 . The upper casing half  30  is integrally formed with the lever bracket  14 . Thus, when the upper and lower casing halves  30  and  32  are coupled together, the entire outer casing  18  is connected to the handlebar  13  through the mounting portion  14 a of the lever bracket  14 .  
         [0029]    The shifting levers  22  and  24  and the cable operated winding mechanism  20  are attached to a support member  15  that is mounted within the outer casing  18  via the bolt  34  and the nut  36 . The shifting levers  22  and  24  are interlocked to the cable operated winding mechanism  20  through a take-up element  38  and a known ratchet-type interlock mechanism. This interlock mechanism includes a ratchet type feed pawl (not shown) for transmitting a pivotal movement of a shift lever  22  to the take-up element  38 , a positioning pawl (not shown) for returning the take-up element  38  in a predetermined rotational position, a limiter pawl (not shown) for limiting an unwinding rotation of the take-up element  38 , and a release cam (not shown) for disengaging the positioning pawl from the take-up element  38 .  
         [0030]    By operating the shift levers  22  and  24 , the take-up element  38  is rotated to pull or release an inner wire  40  of the control cable  41 . For example, when the shift lever  22  is shifted in an upshift direction U from an original position N 1 , the take-up element  38  rotates in a winding direction to take up the inner wire  40  of the control cable  41  as seen in FIG. 4. The shift lever  22  can be released after being operated a predetermined amount necessary for effecting a gear change. Then, the shift lever  22  automatically returns to the original position under the biasing force of a return spring (not shown). At this time, despite the return to the original position of the shift lever  22 , the take-up element  38  is retained in a position to which the take-up element  38  has been rotated by the shift lever  22  to complete the gear change. The shift lever  22  is shiftable in a downshift direction D from an original position N 2  as seen in FIG. 4.  
         [0031]    Thereafter, the shift lever  24  can be released to be returned to its original position by the biasing force of a return spring (not shown). Then, the take-up element  38  rotates by an angle of one pitch in the unwinding direction under the force of an unwind spring (not shown) and a restoring force of the shifting device (derailleur) provided by the inner wire  40 . Consequently, the shift control device  12  unwinds the inner wire  40  of the control cable  41  to effect a one-stage gear shift.  
         [0032]    As best seen in FIG. 5, the outer casing  18  has a cable receiving bore  42  and an access opening  44  formed between the upper casing half  30  and the lower casing half  32  as well as a pair of shift lever openings  46  and  48  formed therebetween. As best seen in FIG. 10, the upper casing half  30  and the lower casing half  32  each includes curved L-shaped rails  50  and  52  that are vertically spaced apart to form a curved channel for slideably receiving a maintenance cover  54 . The rails are located so that the maintenance cover  54  can slide between closed position overlying the access opening  44  and an open position exposing the access opening  44 . The rails  50  and  52  are also provided with a stop  58  at one end to limit the movement of the maintenance cover  54 .  
         [0033]    As best seen in FIGS.  8  an  9 , the maintenance cover  54  is a generally curved member having a curvature that conforms to the curvature of the outer surface of the outer casing  18 . Preferably, as seen in FIG. 10, the maintenance cover  54  has a pair of guide edges  54   a  that are received between the rails  50  and  52  and the upper and lower casing halves  30  and  32  for slideably being received within the channel formed therebetween. As best seen in FIGS.  8  an  9 , the maintenance cover  54  is provided with a plurality of ribs  54   b  that form a handle element, which is arranged to aid in moving the maintenance cover  54  between the closed and open positions. The ribs  54   b  that form the handle element are located at one end of the maintenance cover  54 . The other or opposite end of the maintenance cover  54  is provided with a latching or locking arrangement that releasably locks the maintenance cover  54  in the closed position as seen in FIGS. 7 and 9.  
         [0034]    In particular, the outer casing  18  and maintenance cover  54  include complementary retaining elements. Preferably, the maintenance cover  54  has a recess or notch  54   c  that forms a first complementary retaining element while the outer casing  18  includes a second complementary retaining element in the form of a latching element or portion  56 . This latching element  56  can be a protrusion or merely edge portion of a part of the outer casing  18 . Thus, the notch  54   c  engages the latching portion  56  of the upper and lower casings  30  and  32  to lock the maintenance cover  54  in the closed position. In particular, when the maintenance cover  54  is moved from the open position to the closed position, the end of the maintenance cover  54  with the notch  54   c  will slide underneath the latching portion  56  of the upper and lower casing halves  30  and  32  to releasably lock the maintenance cover  54  in the closed position. Preferably, this locking arrangement is accomplished by having the maintenance cover  54  being flexed slightly inwardly towards the access opening  44  such that the maintenance cover  54  is elastically deformed. This results in the maintenance cover  54  applying an outwardly directing force on the latches to hold the maintenance cover  54  in the closed position.  
         [0035]    It will be apparent to those skilled in the art from this disclosure that the upper and lower casings  30  and  32  and the maintenance cover  54  can be constructed of a variety of materials. These materials include various plastics and metals.  
         [0036]    The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.  
         [0037]    While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.