Abstract:
A bicycle shift control device for controlling a gas actuated shifting device includes a housing; a first gas valve actuating member; a second gas valve actuating member; a first shift member coupled to the housing for movement in a first direction, wherein the first shift member is operatively coupled to the first gas valve actuating member; and a second shift member coupled to the housing for movement in a second direction, wherein the second shift member is operatively coupled to the second gas valve actuating member.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to control devices for bicycle transmissions and, more particularly, to a bicycle shift control device for controlling a gas actuated shifting device. 
     U.S. Pat. No. 6,066,057 entitled “Gas Actuated Transmission for a Bicycle” discloses various embodiments of a gas actuated shifting device for bicycles wherein air controlled shift valves in the form of toggle switches are used to selectively upshift and downshift a gas actuated transmission. Such shift valves can be placed in various positions on the bicycle. However, if the shift valves are formed as separate units, then it may be difficult to position the shift valves in an ergonomic manner. 
     Some shift control devices use two levers in close proximity to each other for respectively upshifting and downshifting the bicycle transmission. Such a device is disclosed in U.S. Pat. No. 5,564,310, for example. The shifting device disclosed in that patent includes two levers that operate in opposite directions to respectively upshift and downshift a bicycle transmission. Such a shifting device is very convenient, but such convenience so far has not been realized in a shift control device for controlling a gas actuated bicycle transmission. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a bicycle shift control device for controlling a gas actuated shifting device which is constructed to maximize ease of use by the rider. In one embodiment of the present invention, a bicycle shift control device for controlling a gas actuated shifting device includes a housing; a first gas valve actuating member; a second gas valve actuating member; a first shift member coupled to the housing for movement in a first direction, wherein the first shift member is operatively coupled to the first gas valve actuating member; and a second shift member coupled to the housing for movement in a second direction, wherein the second shift member is operatively coupled to the second gas valve actuating member. 
     In a more specific embodiment, the first shift member comprises a first shift lever coupled to the housing for rotating in the first direction around a first axis, and the second shift member comprises a second shift lever coupled to the housing for rotating in the second direction around a second axis. The first direction may be the same as the second direction, or the first direction may be opposite the second direction. A first biasing mechanism may be provided for biasing the first shift lever to a first home position, and a second biasing mechanism may be provided for biasing the second shift lever to a second home position. That way the first and second shift levers may automatically return to their respective home positions after the shifting operation is completed. 
     A base member also may be provided for mounting the housing to a handlebar. In this case the base member may include one or more slots for adjustably fastening the housing to the base member. To further facilitate ergonomic positioning of the shift levers, the housing may comprise a first housing section coupled to the first shift lever and a separate second housing section coupled to the second shift lever. The first and second housing sections may be fastened together to position the shift levers on a desired orientation relative to each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a particular embodiment of a bicycle shift control device according to the present invention; 
     FIG. 2 is a top view of the shift control device shown in FIG. 1; 
     FIG. 3 is a view taken along line III—III in FIG. 1; 
     FIG. 4 is a view taken along line IV—IV in FIG. 3 showing a particular embodiment of an air valve according to the invention in an inoperative state; 
     FIG. 5 is a view of the air valve of FIG. 4 in an operative state; 
     FIG. 6 shows an alternative embodiment of a bicycle shift control device according to the present invention; 
     FIG. 7 shows another alternative embodiment of a bicycle shift control device according to the present invention; 
     FIG. 8 shows another alternative embodiment of a bicycle shift control device according to the present invention; 
     FIG. 9 shows another alternative embodiment of a bicycle shift control device according to the present invention; and 
     FIG. 10 shows another alternative embodiment of a bicycle shift control device according to the present invention; 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIG. 1 shows a particular embodiment of a bicycle shift control device  10  according to the present invention coupled for operating a gas actuated bicycle transmission such as a derailleur  14 . Derailleur  14  may be constructed in accordance with the teachings of U.S. Pat. No. 6,066,057 entitled “Gas Actuated Transmission for a Bicycle” and incorporated herein by reference. For example, derailleur  14  may include a downshift gas actuator  18  operated by compressed gas received through a gas line  22  and an upshift gas actuator  26  operated by compressed gas received through a gas line  30 . Downshift gas actuator  18  and upshift gas actuator  26  move a chain guide  32  laterally to shift a bicycle chain (not shown) in a conventional manner. Compressed gas supplied by a compressed gas cylinder  34  is supplied to shift control device  10  through an input gas line  38  and is then selectively routed to downshift gas actuator  18  and upshift gas actuator  26  by shift control device  10 . 
     As shown in FIGS. 1-3, shift control device  10  includes a base member  40 , a housing  42  comprising a first housing section  44  and a second housing section  48 , and shift members in the form of shift levers  52  and  56 . Base member  40  has a handlebar attachment collar  60  for attaching shift control device  10  to a handlebar  64  and parallel oval slots  68  and  72  for adjustably attaching housing  42  to base member  40  through fasteners  76  and  80 . Slots  68  and  72  allow housing  42  to be adjusted in the direction of arrow A shown in FIG. 2 for varying the length L 1  between shift lever  52  and the center of collar  60  (and hence handlebar  64 ) to accommodate the size of the hand of a particular rider. Also, slots  68  and  72  allow housing  42  to be rotationally adjusted in the direction of arrow B to further accommodate the preferences of various riders. In this embodiment, first housing section  44  and second housing section  48  are formed as separate sections that are fastened together by fasteners  76  and  80 . Thus, if desired the spacing between first housing section  44  and second housing section  48  may be adjusted in the direction of arrow C shown in FIG. 3 to yet further accommodate the preferences of various riders. 
     First housing section  44  has a first input gas opening  84  for receiving compressed gas from compressed gas cylinder  34  and a first output gas opening  88  for supplying compressed gas to downshift gas actuator  18 . Lever  52  is pivotably coupled to first housing section  44  through a pivot shaft  92  so that lever  52  pivots in a plane P 1  around an axis X in a direction indicated by arrow D from a home position shown in solid line in FIG.  2 . Similarly, second housing section  48  has a first input gas opening  92  for receiving compressed gas from compressed gas cylinder  34  and a first output gas opening  96  for supplying compressed gas to upshift gas actuator  26 . Lever  56  is pivotably coupled to second housing section  48  through a pivot shaft  100  so that lever  56  pivots in a plane P 2  around an axis Y in a direction indicated by an arrow E from a home position shown by the solid line in FIG.  2 . In This embodiment, axis X is parallel to axis Y, and plane P 1  is parallel to plane P 2 . As discussed in more detail below, each lever  52  and  56  automatically returns to its home position after the shifting operation. 
     FIG. 4 is a view taken along line IV—IV in FIG. 3 showing a particular embodiment of a gas valve  104  according to the invention that is disposed within first housing section  44 . Gas valve  104  is used to selectively communicate compressed gas from input gas opening  84  to output gas opening  88 . Gas valve  104  is shown in FIG. 4 in the inoperative state where the compressed gas at gas input opening  84  is prevented from passing to gas output opening  88 , and gas valve  104  is shown in FIG. 5 in an operative state where the compressed gas at gas input opening  84  is allowed to pass to gas output opening  88 . The same type of gas valve (not shown) is disposed in second housing section  48  for operation by lever  56 , so a detailed description of that gas valve shall be omitted. 
     As shown in FIG. 4, an abutment  108  on shift lever  52  contacts a gas valve actuating member  112  disposed within a valve bore  118 . Gas valve actuating member  112  slidably meshes with a valve pin  116  that is also disposed within valve bore  118 . In the position shown in FIG. 4, a space  119  is disposed between gas valve actuating member  112  and valve pin  116  for reasons discussed below. Gas valve actuating member  112  is fitted within an annular gas exhaust collar  120  that has a plurality of circumferentially spaced exhaust openings  124  for allowing gas supplied to downshift gas actuator  18  to exhaust after the shifting operation. An O-ring seal  128  is fitted around the outer peripheral surface of gas actuating member  112  between a first abutment  132  and a second abutment  136 . A spring  140  is disposed between first abutment  132  and an abutment  144  formed by the inner peripheral surface of valve bore  118  for biasing gas valve actuating member  112  to the right to thereby bias shift lever  52  to the home position shown in FIG.  4 . Shift lever  52  includes a motion limiting abutment  148  which contacts the outer surface of first housing section  44  to limit clockwise rotation of shift lever  52  and to position shift lever  52  in its home position. Shift lever  56  has a similar abutment (not shown) to limit counterclockwise rotation of shift lever  56  and to position shift lever  56  in its home position. 
     An O-ring seal  150  is disposed between an abutment  154  and an abutment  158  on valve pin  116  for contacting an abutment  159  formed by the inner peripheral surface of valve bore  118  to prevent the flow of gas from input gas opening  84  through an intermediate passage leading to output gas opening  88 . A spring  166  is disposed between abutment  154  and an abutment  170  on a bore capping screw  174  to bias valve pin  116  to the closed position shown in FIG.  4 . 
     In operation, lever  52  is rotated in the direction indicated by arrow D to actuate the derailleur  14  in the downshifting direction. Since there is a space  119  between gas valve actuating member  112  and valve pin  116 , valve pin  116  initially remains stationary as a result of the biasing force of spring  166  while O-ring  128  on gas valve actuating member  112  engages the inner peripheral surface of valve bore  118  to prevent gas from flowing to exhaust collar  120 . Upon further rotation of shift lever  52 , gas valve actuating member  112  pushes valve pin  116  to the left, thus unseating O-ring  150  from the abutment  159  and allowing gas to flow from input gas opening  84 , through intermediate passage  162  and through output gas opening  88  to actuate downshift gas actuator  18 . 
     Thereafter, the rider removes his or her thumb or finger from shift lever  52 , and shift lever  52  automatically rotates clockwise as a result of the biasing of spring  140 . During this motion, valve pin  116  initially moves to the right so that O-ring  150  is reseated on abutment  159  to again prevent gas from flowing from gas input opening  84  through intermediate passage  162 . Thereafter, gas valve actuating member  112  continues moving to the right to unseat O-ring  128  from the inner peripheral surface of valve bore  118  to allow the compressed gas that actuated downshift gas actuator  18  to exhaust through exhaust collar  120 . 
     The operation of the gas valve disposed within second housing section  48  is the same. 
     While the above is a description of various embodiments of the present invention, further modifications may be employed without departing from the spirit and scope of the present invention. For example, the size, shape, location or orientation of the various components may be changed as desired. The functions of one element may be performed by two, and vice versa. 
     FIG. 6 shows an alternative embodiment of a bicycle shift control device  200  according to the present invention. In this embodiment, a housing  204  is formed as one piece rather than the two piece housing  42  in the previous embodiment. Furthermore, the rotational plane P 1  of shift lever  52  is inclined relative to the rotational plane P 2  of shift lever  56 . 
     FIG. 7 shows another alternative embodiment of a bicycle shift control device  300  according to the present invention. In this embodiment, shift levers  52  and  56  are structured to pivot in the same direction. 
     FIG. 8 shows another alternative embodiment of a bicycle shift control device  400  according to the present invention. This embodiment has a one-piece housing  404  similar to housing  204  in FIG.  6 . However, in this embodiment there is only a single gas input opening  408  for supplying compressed gas to the two gas actuating valves disposed in housing  404 . A single bore within housing  404  may be used to feed the two gas actuating valves. 
     FIG. 9 shows another alternative embodiment of a bicycle shift control device  500  according to the present invention. In this embodiment, shift levers  52  and  56  have been replaced by buttons  504  and  508  that move in the opposite directions indicated by the arrows. Of course, the buttons could be disposed on the same side of the housing so that the buttons move in the same direction, if desired. 
     FIG. 10 shows another alternative embodiment of a bicycle shift control device  500 ′ according to the present invention. This embodiment also uses buttons  504 ′ and  508 ′, but the buttons are located on the opposite ends of the housing. 
     Thus, the scope of the invention should not be limited by the specific structures disclosed. Instead, the true scope of the invention should be determined by the following claims.