Shifting apparatus for a bicycle

Abstract: A shifting apparatus for controlling a change gear device winding or unwinding a cable. The shifting apparatus essentially includes a control member (8) rotatable about a handlebar (1), a takeup drum for winding the cable thereon, a positioning mechanism for retaining the takeup element in each angular position, and an indicator (40) for indicating a speed stage of the change gear device. The indicator (40) is formed separately from the control member (8) and takeup drum, and has an axis different from a rotational axis (x) of the control member. The indicator (40) may be installed in any desired orientation determined freely without regard to orientations of the control member and takeup drum. The shifting apparatus, therefore, has the indicator (40) which is small but easy to see.

Description: BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a shifting apparatus for use on a bicycle for controlling a change gear device through a cable connected to the change gear device, comprising: a frame containing a takeup element and an interlock mechanism and rotatably holding an indicator, a shift control member having a tubular configuration coaxial with a handlebar supported to be rotatable about a first axis corresponding to an axis of the handlebar, the takeup element is rotatable together with said shift control member to wind said cable thereon, whereas the shift control, member is rotating about said first axis, a positioning mechanism for retaining said takeup element in each angular position, and said indicator is designed for indicating a speed stage of said change gear device in response to said angular position of said takeup element, and the interlock mechanism for transmitting rotation of said shift control member to said takeup element, said indicator is formed separately from said shift control member, said indicator is formed separately from said takeup element and rotating around a second axis different from said first axis. DESCRIPTION OF THE RELATED ART A conventional shifting apparatus for a bicycle as noted above is disclosed in Japanese Patent Publication Kokai No. 1983-191682 , for example. This conventional apparatus includes a speed indicator having a plurality of numeric marks provided in one end region of a control member. A guide block overlaps the end region of the control member, and defines a window-like opening in the overlapping potion thereof. With rotation of the control member, one numeric mark after another registers with that opening to indicate a selected speed stage. Thus, in the above conventional apparatus, the indicator has a rotatable member thereof which is a portion of the control member and is therefore rotatable with the control member about the same axis. To facilitate observation of speed stage indications, at least a portion of the rotatable member is enlarged to present a large display surface, or the display surface is oriented in a way to facilitate view. However, this measure inevitably requires enlargement of the entire shifting apparatus, which is contrary to compactness of the shifting apparatus. In US patent 3 633 437 a shifting apparatus for a bicycle is disclosed which comprises a control member mounted rotatably around the handlebar of a bicycle in the proximity of the grip on the handlebar and a takeup element to wind the cable connected to the change-gear device, wherein the takeup element is mechanically interengaged with the control member for rotation about an axis angularly intersecting the axis of rotation of the control member. The takeup element also comprises an indicator for indicating the current speed stage. In said document the indicator is separated from the control member, but it is part of the takeup member, i.e. the indicator is rotatable about the same axis as the takeup element. Therefore, this arrangement is limited to special shifting devices and it cannot be used for shifting apparatus in which the control member and the takeup element are both rotatably mounted on the axis of the handlebar of a bicycle. SUMMARY OF THE INVENTION The object of the present invention is to provide a shifting apparatus for a bicycle having a compact overall construction with an indicator easily seen by the cyclist. In order to fulfill the above object, the present invention provides an improvement on the type of shifting apparatus noted in the outset hereof, in which the rotational axis of the takeup element is different from the rotational axis of the control member and that the rotational axis of a rotatable member being a part of the indicator, which is the rotational axis of the indicator, is different from the rotational axis of the takeup element. The feature that the indicator is formed separately from the control member and takeup element, and has a rotational axis different from a rotational axis of the control member and of the take up element, allows the indicator to be installed in any desired orientation determined freely without regard to orientations of the control member and takeup element. The indicator may have an entire display plane facing upward, rearward or inwardly of the bicycle to facilitate view by the cyclist. The shifting apparatus, therefore, has the indicator which is relatively small but easy for the cyclist to see. With the indicator small but located in a way to facilitate its view, the cyclist can easily discern speed stages indicated to effect shifting operations reliably, and yet the apparatus itself is small and attachable to the handlebar compactly. The indicator may have a varied display plane facing upwardly or rearwardly of the bicycle. Further, the indicator may employ a varied interlocking mechanism between a rotatable member thereof and the control member or an engaging mechanism. As shown in particular, the indicator may have a display plane inclined inwardly of the bicycle. This indicator displays speed stages toward the cyclist to facilitate view and shifting operations. Further, the indicator may include a rotatable member interlocked to the takeup element, and a fixed member attached to a frame. With these rotatable member and fixed member, the indicator may be formed compact so that the indicator is disposed very close to the handlebar. That is, the apparatus becomes compact in terms of arrangement of the indicator and arrangement of the takeup element, to be attachable to the handlebar with increased simplicity. The shifting apparatus may be attached to the handlebar independently of a brake lever. However, the shifting apparatus may have a bracket extending from the frame for pivotally supporting a brake lever. Then, the brake lever may be attached to the handlebar, utilizing a construction that attaches the shifting apparatus to the handlebar. This allows the brake lever and shifting apparatus to be attached as a unit to the handlebar, and that in a compact manner. The frame of the shifting apparatus and the brake bracket may be formed of an identical material to be integral with each other. The integration of the frame and bracket realizes a relatively compact construction for attaching the shifting apparatus and brake lever to the handlebar. That is, the apparatus may be formed compact in the aspect of its attachment. Other features and advantages of the present invention will be apparent from the following description of the preferred embodiments taken with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of a shifting apparatus Fig. 2 is a sectional view of an engaging mechanism mounted in the shifting apparatus of Fig. 1. Fig. 3 is a sectional view of a takeup element mounted in the shifting apparatus of Fig. 1. Fig. 4 is a sectional view of a speed indicator of the shifting apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Fig. 1 to 4, wherein only the embodiment of Fig 4 falls within the scope of the claim, a frame 2 has a band 2a fastened tight to a bicycle handlebar 1. The frame 2 contains a wire takeup element 3. The frame 2 is provided with an outer holder 5 for supporting a control cable 6 extending from a change gear device (not shown) of the bicycle. The control cable 6 has an inner wire 6a guided from the outer holder 5 into the frame 2. The inner wire 6a is connected to the takeup element 3. The takeup element 3 is rotatable by a control member 8 disposed outside the frame 2. The takeup element 3 rotated to a selected position is retained in that position by an engaging mechanism 20. A brake lever 10 is pivotally connected to a bracket 9 formed integral with and of the same material as the frame 2. Thus, the shifting apparatus may be attached along with the brake lever 10 to the handlebar 1. In other words, this is a shifting apparatus having a brake lever. By operating the control member 8 to rotate the takeup element 3, the inner wire 6a of the control cable 6 is pulled or relaxed to switch the change gear device of the bicycle. At the same time, an indicator 40 having a rotatable member 42 attached to the frame 2 allows the cyclist to discern a speed stage provided by the change gear device. Details of this apparatus will be described hereinafter. In the shifting apparatus for a bicycle shown in Fig. 1 to 4, the frame 2 has said band 2a fastened tight to a bicycle handlebar 1 inwardly of a grip 11. The control member 8 is rotatably mounted adjacent a side of the frame 2. As shown in Figs. 1 and 2, the frame contains and covers the takeup element 3 and the engaging mechanism 20 arranged forwardly of the band 2a. The indicator 40 is disposed in a similar position. As clearly seen in Fig. 3, rotation of the control member 8 is transmitted to the takeup element 3 and engaging mechanism 20 arranged forwardly, through a bevel gear 13 rotatable with the control member 8, a bevel gear 14 meshed with the bevel gear 13, a spur gear 15 rotatable with the bevel gear 14, and a spur gear 16 meshed with the spur gear 15. The outer tube of the control cable 6 extending from a change gear device of the bicycle is supported by the outer holder 5 provided on the frame 2. The inner wire 6a of the control cable 6 extends into the frame to be connected to the takeup element 3. By operating the control member 8 to rotate the takeup element 3, the inner wire 6a of the control cable 6 is pulled or relaxed to switch the change gear device. An indicator 40 allows the cyclist to discern a speed stage provided by the change gear device. In this embodiment of Fig. 1 to 3, which does not fall within the scope of the claim, the indicator 40 is rotatable about the same axis as the takeup element 3. With use of both bevel gears and spur gears, the indicator 40 and takeup element 3 are spaced from the rotational axis of the control member 8. This construction has the advantage of allowing a freedom for arranging the indicator 40 over the case of using only bevel gears so that the rotational axis of the indicator 40 crosses the rotational axis X of the control member 8. Details of the construction of this embodiment are as follows. The control member 8 has a tubular configuration coaxial with a handlebar receiving bore of the band 2a, and is rotatably mounted on the handlebar 1 inwardly of the grip 11. The control member 8 is rotatable forward and backward. As shown in Fig. 3, the bevel gear 13 provided at one end of the control member 8 is interlocked through the bevel gear 14 and spur gear 15 to the spur gear 16 provided at a lower end of the takeup element 3. Thus, when the control member 8 is rotated backward, the takeup element 3 rotates backward about rotational axis Y3. The takeup element 3 then winds the inner wire 6a thereon and pulls the inner wire 6a. When the control member 8 is rotated forward, the takeup element 3 also rotates forward to unwind the inner wire 6a therefrom and relax the inner wire 6a. As shown in Fig. 2, the engaging mechanism 20 includes ratchet teeth 24 formed peripherally of the takeup element 3 and having tooth bottoms 24a corresponding in number to the speed stages provided by the change gear device, and an elastic engaging element 23 mounted on an inner wall of the frame 2. When the takeup element 3 is rotated by a torque exceeding a predetermined force, the engaging element 23 is elastically deformed by the pressure of a ratchet tooth 24 acting on an engaging pawl 23a of the engaging element 23. The engaging pawl 23a moves from a bottom 24a onto a top of the ratchet tooth 24. Then, the engaging element 23 is temporarily disengaged from the ratchet teeth 24. When the takeup element 3 reaches a selected angular position, the engaging pawl 23a moves into one of the tooth bottoms 24a under an elastic restoring force of the engaging element 23. Then, the engaging element 23 engages a ratchet tooth 24 to stop the takeup element 3. As shown in Figs 1 and 3, the indicator 40 includes a rotatable member 42 attached to an upper end of the takeup element 3 and having a pointer 41 as shown in Fig. 1, and a fixed member 43 fastened to the frame 2 by screws. The fixed member 43 includes a portion 43a formed of a transparent material and disposed above the rotatable member 42. Thus, the pointer 41 is seen from outside. The fixed member 43 acts also as a lid for closing an opening of the frame 2 which accommodates the takeup element 3. The rotatable member 42 is attached to the upper end of the takeup element 3 by screws. In addition, the rotatable member 42 is interlocked to the takeup element 3 through engagement between a stopper pin 42a on the rotatable member 42 and a mounting shank 3c on the takeup element 3. When the takeup element 3 is rotated the rotatable member 42 rotates with the takeup element 3 about the common axis Y3, and hence the pointer 41 also turns at the same time. When the takeup element 3 reaches a selected angular position to switch the change gear device to a selected speed stage, the pointer 41 turns to an angular position indicating one, corresponding to the selected speed stage of the change gear device, of a plurality of speed marks 44 provided on the fixed member 43 (Fig. 1). Thus, the indicator 40 is formed separately from the control member 8, and mounted on the frame 2 to be rotatable on the axis Y3 different from the rotational axis X of the control member 8. This indicator 40 includes the rotatable member 42 interlocked to the takeup element 3, and the fixed member 43 attached to the frame 2. The indicator 40 receives a torque from the control member 8 through the takeup element 3. A speed stage of the change gear device is indicated by a combination of the pointer 41 on the rotatable member 42 and a speed mark 44 on the fixed member 43. The indicator 40 has a rotational axis, which is the rotational axis Y3 of the rotatable member 42, different from the rotational axis X of the control member 8. Where the handlebar 1 is a flat bar, the indicator 40 has a display plane facing upward to facilitate view by the cyclist. Fig. 4 shows an indicator structure according to the invention as a modification of that of Figs. 1 through 3. This indicator 40 is formed separately from the takeup element 3, and may therefore be positioned with an increased degree of freedom. For example, the indicator 40 may be inclined with respect to the axis of the takeup element 3. Details of this construction are as follows. The indicator 40 has a rotatable member 42 attached to the frame 2 through a fixed member 43 to be rotatable about an axis Y4 substantially crossing the rotational axis Y3 of the takeup element 3. The rotatable member 42 includes a pair of driven tongues 42b formed on a reverse side thereof, while the takeup element 3 includes a drive pin 3d having a distal end thereof extending to a position between the driven tongues 42b. Thus, the rotatable member 42 is interlocked to the takeup element 3, whereby rotation of the takeup element 3 causes the rotatable member 42 to rotate about the axis Y4. That is, when the takeup element 3 rotates, the drive pin 3d makes slidable contact with and presses one of the driven tongues 42b, thereby transmitting a torque from the takeup element 3 to the rotatable-member 42. Although the rotational axes Y3 and Y4 cross each other, the rotatable member 42 is rotatable in response to rotation of the takeup element 3. The pair of driven tongues 42b may be in the form of a cylinder opening downward. Thus, the rotatable member 42 is formed separately from the control member 8 and takeup element 3, and is interlocked to the takeup element 3 to be rotatable by a torque of the control member 8 transmitted through the takeup element 3. A speed stage of the change gear device is indicated by a combination of a pointer 41 on the rotatable member 31 and a speed mark 44 on the fixed member 43. The rotational axis Y3 of the takeup element 3 is different from the rotational axis X of the control member 8. Furthermore, the rotational axis Y4 of the rotatable member 42, which is a rotational axis of the indicator 40, is different from the rotational axis Y3 of the takeup element 3. Consequently, the indicator 40 may be disposed with an increased degree of freedom. Where the handlebar 1 is a flat bar, the indicator 40 has a display plane facing obliquely upward and inclined inwardly of the bicycle, as shown in Fig. 4, to facilitate view by the cyclist. The engaging mechanism 20 may be replaced by a friction mechanism for applying a frictional resistance to the takeup element to retain the takeup element in a selected angular position. Thus, these mechanisms are collectively called herein a positioning mechanism 20. The indicator described has a pointer provided on the rotatable member, and speed marks on the fixed member. Instead, the speed marks may be provided on the rotatable member, and the pointer on the fixed member. The present invention is applicable also to a shifting apparatus for use on a handlebar curved to have grips extending longitudinally of a bicycle. The invention is applicable also to a shifting apparatus attachable to a handlebar separately from a brake lever. Further, the invention is applicable also to a shifting apparatus including a control member having such a length that an outward end thereof reaches one end of the handlebar, so that the control member acts as a rotatable grip in place of the handlebar grip 11 described hereinbefore.

Claims: A shifting apparatus for use on a bicycle for controlling a change gear device through a cable (6a) connected to the change gear device, comprising: a frame (2) containing a take up element (3) and an interlock mechanism (14, 15, 16) and rotatably holding an indicator (40), a shift control member (8) having a tubular configuration coaxial with a handlebar supported to be rotatable about a first axis (X) corresponding to an axis of the handlebar (1), the takeup element (3) is rotatable together with said shift control member (8) to wind said cable (6a) thereon whereas the shift control member (8) is rotating about said first axis (X), a positioning mechanism (23, 24) for retaining said takeup element (3) in each angular position, and said indicator (40) is designed for indicating a speed stage of said change gear device in response to said angular position of said takeup element (3), and the interlock mechanism (14, 15, 16) for transmitting rotation of said shift control member to said takeup element (3), said indicator (40) is formed separately from said shift control member (8), said indicator (40) is formed separately from said takeup element (3) and rotating around a second axis (Y) different from said first axis (X), characterized in that the rotational axis (Y3) of the takeup element (3) is different from the rotational axis (X) of the control member (8) and that the rotational axis (Y4) of a rotatable member (42), being a part of the indicator (40), which is the rotational axis of the indicator (40), is different from the rotational axis (Y3) of the takeup element (3).

Inventors: KOJIMA MASAO, SYOGE AKIHIKO, KOJIMA, MASAO, SYOGE, AKIHIKO
Applicants: SHIMANO KK, SHIMANO INC.
Application year: 1995
Main classification: B62M25
IPC codes: B62M25, G05G1, B62K23, B62J99