BICYCLE AND SPEED CHANGE OPERATING DEVICE FOR THE SAME

Abstract: A bicycle comprising a front derailleur having a plurality of speed change gears, a rear derailleur having at least three speed change gears, a front speed change operating device (1A) connected to the front derailleur and a rear speed change operating device (1B) connected to the rear derailleur, wherein there are a plurality of groups of specific combinations of speed change gears of the front derailleur with speed change gears of the rear derailleur, and wherein indication means (50a to 50c, 59A, 51a to 51c and 59B) for identifying the plurality of group of those combinations are provided on the front speed change operating device (1A) and the rear speed change operating device (1B), respectively.

Description: Technical Field The present invention relates to a bicycle speed change operation system and a bicycle equipped therewith. Background Art A bicycle equipped with a speed shifter such as a derailleur and a hub gear is commonly equipped with a speed change operation assembly connected to the speed shifter via a control cable. Desired speed change operation is performed by operating the speed change operation assembly. In such a bicycle it is desirable for a rider to be able to know easily what speed stage he is using. Thus a conventional speed change operation assembly has a scale showing the speed positions such as first gear and second gear. Recently, bicycle speed shifter tends to have an increasing number of speed stages. Especially, a sports type bicycle is now commonly equipped with a front speed shifter having two or a greater number of speed stages, and with a rear speed shifter having three or a greater number of speed stages. However, such a bicycle having a front and a rear speed shifters is only equipped with a pair of speed change operation assemblies for respective front and rear speed shifters, and each speed change operation assembly is provided with a scale solely showing the speed stages of its own speed shifter. This type of conventional arrangement in which each of the two speed change operation assemblies only has an individual scale for its own speed stages has following problems: Reference is now made to Fig. 6, which shows an enlarged plan view of a primary portion of a bicycle equipped with a front derailleur (not shown) capable of shifting a chain 4A between three front gears F1 through F3, and a rear derailleur (not shown) capable of shifting a chain 4A between six rear gears R1 through R6. In this bicycle, chain 4A currently engages with front gear F1 and rear gear R4. If a speed change operation to a lower speed stage is to be made, it is more desirable to shift a front portion of chain 4A to the front gear F2 than shifting a rear portion of chain 4A to the rear gear R5 or R6, because as shown in the phantom line in Fig. 6, shifting the chain 4A to the rear gear R5 or R6 will increase an engagement angle Θ of chain 4A, resulting in noise or easy disengagement of chain due to poor engagement between the chain and the gears. In addition, the service life of chain 4A will be shortened because the chain 4A is subjected to lateral forces other than tension. There is another problem if the rear portion of chain 4A is shifted to the rear gear R6: A speed change operation to a further lower speed stage can no longer be achieved by operating the rear derailleur, and therefore, a front portion of the chain 4A must be shifted to the front gear F2. If there is still further need to shift down, the only option is to shift the front portion of chain 4A to the front gear F3. This type of speed change operation practice only makes use of large gear ratios between front gears, making unavailable the access to more advantageous 6 speed options provided by the rear gears R1 through R6 having a smaller gear ratios for finer speed control. As exemplified in the above, in a bicycle equipped with a front speed shifter and a rear speed shifter, there are certain favorable and unfavorable combinations of a front speed stage and a rear speed stage. However, in a conventional bicycle, the front speed stage and the rear speed stage can only be confirmed individually. The rider cannot know easily how he can advantageously combine a front speed stage with a rear speed stage. Even if he knows favorable combinations, it is still very difficult for him to make such a setting quickly while riding on a bicycle. Moreover, the European patent application EP-A-0 641 711 discloses a device for displaying the speed stages of the front speed shifter and the rear speed shifter of a bicycle. The device has a liquid crystal display showing three rows arranged vertically and transversely and indicating the speed stage of the front speed shifter. Each row consists of seven blocks arranged transversely and indicating the speed stage of the rear speed shifter. In order to display the current speed stage the corresponding block is turned off. Disclosure of the Invention It is therefore an object of the present invention to provide easy means for a bicycle rider to make a favorable gear combination between a speed stage of a front speed shifter and a speed stage of a rear speed shifter. According to the present invention, a bicycle speed change operation system comprises a front speed change operation assembly connected to a front speed shifter having a plurality of speed stages, and a rear speed change operation assembly connected to a rear speed shifter having at least three speed stages. There are a plurality of designated groups of combinations for combining the speed stages of the front speed shifter with the speed stages of the rear speed shifter, and indication means for identifying each of these groups is provided for each of the front speed change operation assembly and the rear speed change operation assembly. According to the present invention, if the bicycle rider follows the indication given by the above indication means when operating the front speed change operation assembly or the rear speed change operation assembly, a resulting combination between a front speed stage and a rear speed stage will belong to a designated group. On the other hand, the above indication means can keep the combination between a front speed stage and a rear speed stage within the designated favorable range. As a result, according to the present invention, the bicycle rider can easily achieve a favorable combination between a front speed stage and a rear speed stage by following the indications given by the indication means. According to a preferred embodiment of the present invention, the indication means comprises a first group of differently colored indicator marks each corresponding to a respective speed stage of the front speed shifter, and a second group of differently colored indicator marks each corresponding to plural speed stages of the rear speed shifter. The color of each indicator mark in the first group is similar to the color of one indicator mark in the second group for showing recommended combinations of each speed stage of the front speed shifter with a plurality of speed stages of the rear speed shifter. According to the above arrangement, it is possible to make a designated favorable combination of a front speed stage and a rear speed stage by operating the front speed change operation assembly or the rear speed change operation assembly so that a color of the first group of indicator marks is the same with the color of the second group of indicator marks. In this way, by judging from the colors of the indicator marks, the rider can easily know what favorable speed change options are available at any time. According to another preferred embodiment of the present invention, the speed change operation assembly comprises a grip-type operation member rotatably fitted around an end portion of the handlebar. In this embodiment, the grip-type operation member of the front speed change operation assembly and the grip-type operation member of the rear speed change operation assembly are designed such that the front speed shifter and the rear speed shifter are equally shifted to either one of a higher speed stage or a lower speed stage when they are rotated in the same direction. The above arrangement can reduce possibilities for misoperation when a speed change is made to a lower or a higher speed stage because each of the front speed change operation assembly and the rear speed change operation assembly is rotated in an identical direction. According to the present invention, a bicycle is equipped with the aforementioned bicycle speed change operation system. Other features and advantages of the present invention will become apparent from the following description of the preferred embodiment given with reference to the accompanying drawings. Brief Description of the Drawings Fig. 1 is a plan view showing a primary portion a bicycle speed change operation assembly according to the present invention. Fig. 2 is an enlarged plan view of portion A in Fig. 1. Fig. 3 is an enlarged plan view of portion B in Fig. 1. Fig. 4 is a plan view showing a primary portion of a bicycle driving mechanism for chain shift operation by the bicycle speed change operation assembly shown in Fig. 1. Fig. 5 is a view showing another indication means of the bicycle speed change operation assembly according to the present invention. Fig. 6 is a plan view of a primary portion of a conventional bicycle showing an example of chain engagement. Best Mode for Carrying Out the Invention An embodiment of the present invention is described below with reference to the accompanying Figs. 1 through 6. A bicycle speed change operation system shown in Fig. 1 comprises a front speed change operation assembly 1A and a rear speed change operation assembly 1B. Each of the front speed change operation assembly 1A and the rear speed change operation assembly 1B is located between a handle grip 91 fitted at an end portion of the handlebar 9 and a bracket 93 of a brake lever 92. The front speed change operation assembly 1A is used for operating a front derailleur (not shown) for shifting a chain 4 between front gears 2a through 2c driven by a crank arm 94 shown in Fig. 4. The front derailleur and the front speed change operation assembly 1A are mutually connected by a control cable C (CA) . The front derailleur is a conventional type. More particularly, this front derailleur has a shifter for moving the chain 4 width-wise of the bicycle in correspondence to the amount of pull of the control cable C (CA). The rear speed change operation assembly 1B is used for operating a rear derailleur (not shown) for shifting a chain 4 between six-stage rear gears 3a through 3f fitted to a rear hub 95. The rear derailleur and the rear speed change operation assembly 1B are mutually connected by a control cable C (CB). The rear derailleur again, is a conventional type. More particularly, this rear derailleur has a guide pulley for moving the chain 4 width-wise of the bicycle in correspondence to the amount of pull of the control cable C (CB), and a tension pulley for removing slack in the chain 4. Each of the control cable C comprises an inner wire and an outer sheath which is a tube provided for guiding the inner wire. An end of the inner wire is connected to a respective derailleur. The inner wire is under a constant pull toward the derailleur by an elastic force of a spring of the derailleur. The front speed change operation assembly 1A and the rear speed change operation assembly 1B are primarily the same in constitution. The rear speed change operation assembly 1B comprises a housing 5, wire reel 6, and grip-type operation member 7. The housing 5 receives the wire reel 6, and guides the control cable C. The housing 5 includes a cylindrical housing body fitted around the handlebar 9, and a wire-guide portion projecting from the housing body. A cylindrical portion of the housing body allows rotation of the wire reel 6 relative to the housing 5. The wire-guide portion curving toward a side of the housing 5 has a guide hole for guiding the inner wire of the control cable C. The wire reel 6 is for winding (pulling) or unwinding the inner wire. The grip-type operation member 7 is for rotating the wire reel 6 and is generally formed in a cylindrical shape for fitting around the wire reel 6. The wire reel 6 and the housing is made of a synthetic resin for example, whereas the grip-type operation member 7 is made of a synthetic rubber for example, for reducing slip on the rider's hand. For the same purpose, the grip-type operation member 7 is formed with a non-slip embossing pattern on its outer surface. Thus, when the grip-type operation member 7 is fitted around the wire reel 6, their relative rotation is prohibited, and they only rotate together. However, it should be noted that the rear speed change operation assembly 1B is set to top-normal whereas the front speed change operation assembly 1A is set to low-normal. More specifically, in the rear speed change operation assembly 1B, the chain 4 engages with the gear 3f (top gear) which is the outermost gear when the inner wire is not pulled. On the other hand, in the front speed change operation assembly 1A, the chain 4 engages with the gear 2a (low gear) which is the inner-most gear when the inner wire is not pulled. In addition, the inner wire passes above the handlebar 9 for connection to the wire reel 6 in the rear speed change operation assembly 1B. Thus, when the grip-type operation member 7 and the wire reel 6 in the rear speed change operation assembly are rotated backwardly, the inner wire is wound around the wire reel 6 for successive speed change to a lower speed stage. On the other hand, contrary to the above rear speed change operation assembly 1B, the inner wire of the front speed change operation assembly 1A passes below the handlebar 9 for connection to the wire reel (not shown). Thus, in the front speed change operation assembly 1A, when the grip-type operation member and the wire reel are rotated toward backwardly, the inner wire is released toward the front derailleur for successive speed change to a lower speed stage. After all, the direction of rotation of the grip-type operation member 7 in each of the front speed change operation assembly 1A and the rear speed change operation assembly 1B for shifting either one of a higher speed stage and a lower speed stage is the same. Such arrangement helps eliminating possibilities for a bicycle rider to operate the front speed change operation assembly 1A or a rear speed change operation assembly 1B in a wrong direction during the speed change operation. As shown in Fig. 2, the outer surface of the housing 5 of the front speed change operation assembly 1A is provided with a first scale having numerical figures one (1) through three (3), as well as a first group of indicator marks 50a through 50c of three different colors. The first scale refers to the speed stages of the front derailleur in relation with the indicator needle 59 (59A) provided in the grip-type operation member 7. The speed stages of this front derailleur are: stage "1" when the chain 4 shown in Fig. 4 is on the front gear 2a, and stages "2" and "3" when the chain 4 is on the front gears 2b and 2c respectively. The indicator marks 50a through 50c respectively correspond to the numerical indications of the first scale (i.e. speed stages 1 through 3 of the front derailleur). Each of the indicator marks 50a through 50c of the first group is given a different color from the others, for example, blue, green and red. As shown in Fig. 3, the outer surface of the housing 5 of the rear speed change operation assembly 1B is provided with a second scale having numerical figures one (1) through six (6), as well as a second group of indicator marks 51a through 51 c in the three colors. The second scale refers to the speed stages of the rear derailleur in relation with the indicator needle 59 (59B) provided in the grip-type operation member 7. The speed stages of this rear derailleur are: stage "1" when the chain 4 shown in Fig. 4 is on the rear gear 3a, and stages "2" through "6" when the chain 4 is on the rear gears 3b through 3c respectively. The indicator marks 51 a through 51 c respectively correspond to the numerical indications of the second scale (i.e. speed stages "1" through "6" of the rear derailleur) as well as to the indicator marks 50a through 50c of the first group. More specifically, the indicator mark 51a of the second group corresponds to the numerical indicators "1" through "3" of the second scale and therefore, colored in the same blue as is the indicator mark 50a of the front speed change operation assembly 1A. Another indicator mark 51 b corresponds to the numerical indicators "2" through "5" of the second scale and therefore, colored in the same green as is the indicator mark 50b of the front speed change operation assembly 1A. The other indicator mark 51c corresponds to the numerical indicators "4" through "6" of the second scale and therefore, colored in the same red as is the indicator mark 50c of the front speed change operation member 1A. The indicator marks 50a through 50c of the first group and the indicator marks 51a through 51c of the second group are for differentiating plural groups of favorable combinations by color. More specifically, if the color of one of the indicator marks 50a through 50c pointed by the indicator needle 59 (59A) of the first group is the same color as the color of one of the indicator marks 51a through 51c pointed by the indicator needle 59 (59B) of the second group, a resulting combination of a front derailleur speed stage and a rear derailleur speed stage is a favorable combination. Each of the above indicator marks may be a colored decal adhered on the outer surface of the housing 5, or may be direct color painting or printing for example. Next, description is made on a speed change operation on a bicycle equipped with the front speed change operation assembly 1A and the rear speed change operation assembly 1B. When a front portion of the chain 4 is on the front gear 2c as shown in Fig. 4 for example, indications on the front speed change operation assembly 1A is as shown in Fig. 2, namely, the front derailleur speed stage "3" and the red indicator mark 50c are pointed by the indicator needle 59 (59A). Now, if the bicycle rider is to change speed by operating the rear speed change operation assembly 1B, he should operate so that the indicator needle 59 (59B) points the same color as the indicator mark 50c, that is, the indicator mark 51c of the indicator marks 51a through 51c of the second group shown in Fig. 3. This operation brings a rear portion of the chain 4 to one of the rear gears 3d through 3f, and not anyone of the rear gears 3a through 3c, avoiding the situation where the chain 4 is engaged with a front and a rear gears at a large engagement angle. Thus, it is possible to eliminate noise or easy disengagement of chain 4 due to poor engagement between the chain 4 and the gears. It also makes possible to increase the service life of chain because the chain is not subjected to lateral forces. Now, if a speed change operation to a lower speed stage is to be made under a situation where the front speed change operation member 1A is currently set to the speed stage "3" and the rear speed change operation assembly 1B is currently set to the speed stage "4" for example, a recommended procedure is to operate the front speed change operation assembly 1A to the speed stage "2". In this operation, the indicator needle 59 (59B) of the rear speed change operation assembly 1B stays on the red indicator mark 51c and the green indicator mark 51b, whereas the indicator needle 59 (59A) of the front speed change operation assembly 1A is moved to point the indicator mark 50b which is green. Thus, the speed change operation to a lower speed stage can be performed without making the colors of the front speed change operation member 1B and the front speed change operation member 1A differing from each other. Once the speed stage "2" is selected on the front speed change operation assembly, it is then possible to use only the rear speed change operation assembly 1B for making finer speed change operations by the rear gear 3a through 3f of the 6-stage sprocket. In this embodiment, the combination groups of the front derailleur speed stages and the rear derailleur speed stages are represented by the colored indicator marks 50a through 50c of the first group and 51a through 51c of the second group, so these marks are very easy for the bicycle rider to recognize and understand. The scope of the present invention is not limited to the embodiment described hereinabove. For example, specific combinations of a front derailleur speed stage and rear derailleur speed stages may be designated differently from the embodiment by a bicycle manufacturer or a bicycle dealer. The groups may be differentiated by black and white only, or by different patterns of a single color. Further, instead of the color or pattern, the numerical figures "1" through "6" of the second group of the rear speed change operation assembly 1B for example, may be accompanied by numbers of a different font or size which represent the recommended speed stages of the front derailleur to be coupled with. In this particular case, the front speed change operation assembly 1A may only have indication means for the speed stages of the front derailleur. Furthermore, it is not necessary in the present invention to provide the indication means for the front derailleur speed stages and the rear derailleur speed stages directly on the front speed change operation assembly 1A and the rear speed change operation assembly 1B. For example, providing these indication means on the handlebar or other members is still within the scope of the present invention. Still further, the present invention is not limited to a type of bicycle equipped with a 3-stage front derailleur and a 6- stage rear derailleur. The present invention allows the use a of hub gear for the speed shifter. The present invention is applicable to a bicycle equipped with a front speed shifter of at least 2 speed stages and a rear speed shifter of at least 3 speed stages, and there is no specific limitation to the number of speed stages of the front speed shifter or the rear speed shifter. If the front speed shifter has two speed stages and the rear speed shifter has 6 speed stages, the indication means 59A, 59B may be as shown in Fig. 5. In addition, it is possible in the present invention to use a different type of speed change operation assembly such as once equipped with a rod-type control lever for the front speed change operation assembly and the rear speed change operation assembly. Applicable Field The bicycle and the bicycle speed change operation assembly according to the present invention is widely applicable to a bicycle equipped with a front speed shifter having at least 2 speed stages and a rear speed shifter having at least 3 speed stages.

Claims: A bicycle speed change operation system comprising: a front speed change operation assembly (1A) connected to a front speed shifter having a plurality of speed stages, and a rear speed change operation assembly (1B) connected to a rear speed shifter having at least three speed stages, characterized in that there are a plurality of designated groups of recommended combinations for combining the speed stages of the front speed shifter with the speed stages of the rear speed shifter; and wherein indication means for identifying each of these groups are provided for each of the front speed change operation assembly (1A) and the rear speed change operation assembly (1B). The bicycle speed change operation system according to Claim 1, wherein the indication means comprises a first group of differently colored indicator marks (50a to 50c) each corresponding to a respective speed stage of the front speed shifter, and a second group of differently colored indicator marks (51a to 51c) each corresponding to plural speed stages of the rear speed shifter; the color of each indicator mark (50a to 50c) in the first group being similar to the color of one indicator mark (51 to 51c) in the second group for showing recommended combinations of each speed stage of the front speed shifter with a plurality of speed stages of the rear speed shifter. The bicycle speed change operation system according to Claim 1, wherein each speed change operation assembly comprises a grip-type operation member (7) rotatably mounted at an end portion of a handlebar (9). The bicycle speed change operation system according to Claim 3, wherein the grip-type operation member (7) of the front speed change operation assembly (1A) and the grip-type operation member (7) of the rear speed change operation assembly (1B) are designed such that when they are rotated in the same direction, the front speed shifter and the rear speed shifter are equally shifted to either one of a higher speed stage and a lower speed stage. A bicycle comprising: a bicycle speed change operation system according to any of the preceding claims 1 to 4.

Inventors: IWASAKI YOSHIHISA, SUENAGA TOMONORI, IWASAKI, YOSHIHISA, SUENAGA, TOMONORI
Applicants: SAKAE CO LTD, SAKAE CO., LTD.
Application year: 1996
Main classification: B62M25
IPC codes: B62M25, B62K23