Pulley and bicyle shift control device comprising such a pulley

Abstract: A clamping apparatus for a shifting control device (10) includes a clamping unit and a housing (12) attached to the clamping unit. The clamping unit includes a clamp member structured to mount a handlebar (8) around a first axis coaxial with the handlebar (8), a clamp arm member coupled to the clamp member and extending in a radial direction from the clamping member, and a housing mounting member disposed on the clamp arm member and spaced apart from the clamp member. The housing (12) includes a base member structured to mount to the handlebar (8) around the first axis, a housing arm member coupled to the base member and extending in the direction of the clamp arm member, and a pulley coupling member disposed on the housing arm member and spaced apart from the base member, wherein the pulley coupling member is fixed to the housing mounting member. A pulley (21) is coupled to the pulley coupling member for rotation around a second axis that usually is oriented differently from the first axis. The pulley (21) includes a pulley body having an outer peripheral surface, a first winding groove formed on the outer peripheral surface for winding a first transmission element thereon, and a second winding groove formed on the outer peripheral surface for winding a second transmission element thereon. The first winding groove is inclined relative to the second winding groove.

Description: BACKGROUND OF THE INVENTION The present invention is directed to a pulley and to a bicycle shift control device including such a pulley, and, more particularly, to a shift control device having a compact design to facilitate mounting the shift control device in close proximity to other structures. Twist-grip shift control devices are sometimes used to control various types of bicycle transmissions. Examples of such devices are disclosed in USP 3,633,437 and USP 5,197,927. Each device disclosed in those patents includes a rotatable handgrip mounted around the handlebar coaxially with the handlebar axis, a pulley inclined relative to the rotatable handgrip for winding a transmission cable, and a motion transmitting structure for transmitting motion of the rotatable handgrip to the pulley. In the device disclosed in USP 3,633,437, the motion transmitting member is a pair of bevel gears formed by the peripheral surfaces of the rotatable handgrip and the pulley. The device disclosed in USP 5,197,927 also employs a pair of bevel gears formed by the peripheral surfaces of the rotatable handgrip and the pulley. Alternatively, that device may employ a connecting cable connected between the rotatable handgrip and the pulley. When a connecting cable is used to transmit motion between the rotatable handgrip and the pulley, the pulley typically must have two winding grooves - one for the cable controlling the bicycle transmission and another one for the cable coupling the pulley to the rotatable handgrip. The winding grooves usually are located on an outer peripheral surface of the pulley. The end of each cable is fitted with a terminating nipple that is fitted within a recess formed in the pulley. The pulley ordinarily has a thickness sufficient to accommodate two nipples aligned end to end, even though the two nipples are not always positioned adjacent to each other, in orderto provide sufficient support and rigidity for the two cable nipples. However, such a thickness increases the size of the shift control device, thus making the shift control device aesthetically unappealing, and it makes it difficult to mount the shift control device in close proximity to other devices, such as a brake lever assembly. SUMMARY OF THE INVENTION The present invention is directed to a pulley and to a bicycle shift control device as defined respectively in claims 1 and 12. The first embodiment of the present invention is directed to the pulley according to claim 1. The pulley includes a pulley body having an outer peripheral surface, a first winding groove formed on the outer peripheral surface for winding a first transmission element, and a second winding groove formed on the outer peripheral surface for winding a second transmission element. The first winding groove is inclined relative to the second winding groove. In a more specific embodiment, the pulley has a mounting portion so that the pulley rotates around a rotational axis, wherein the first winding groove is inclined relative to the second winding groove in the direction of the rotational axis. In an even more specific embodiment, the first winding groove includes a first groove segment that is inclined relative to the second winding groove and a second groove segment that is parallel to the second winding groove. This structure allows any terminating nipple on the first transmission element to be placed closerto the second winding groove, thus decreasing the thickness of the pulley over prior art structures. The second embodiment of the invention is directed to a bicycle shift control device including a pulley of the invention. Such a device is defined in claim 12. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a bicycle equipped with a shift control device; Figure 2 is an oblique view of the shift control device shown in Figure 1 mounted together with a brake lever assembly; Figure 3 is an exploded view of a portion of the shift control device shown in Figure 2 illustrating a clamping unit, the housing for the shift control device, and a pulley used to control the transmission control cable; Figure 4A is a plan view of an embodiment of the pulley according to the invention; Figure 4B is a view taken along line IVB-IVB in Figure 4A; Figure 4C is a view taken along line IVC-IVC in Figure 4A; Figure 4D is a view taken along line IVD-IVD in Figure 4B; Figure 4E is a view taken along line IVE-IVE in Figure 4C; Figure 4F is a view similar to Figure 4D showing an altemative embodiment of a cable winding surface used in the pulley according to the present invention; and Figure 5 is an exploded view of an indexing mechanism used in the shift control device shown in Figure 3. DETAILED DESCRIPTION OF THE EMBODIMENTS Figure 1 is a side view of a bicycle 1 equipped with a shift control device 10. Bicycle 1 is a typical bicycle that includes a front wheel 2, a rear wheel 3, pedals 4 for driving a chain 5, and a derailleur 6 that guides chain 5 laterally along a plurality of sprockets 7 mounted to rear wheel 3. Derailleur 6 is controlled by a twist-grip shift control device 10 mounted around a handlebar 8 through a transmission control cable 11. In this embodiment, a brake lever assembly 9 also is mounted around handlebar 8 in close proximity to shift control device 10. Figure 2 is an oblique view of shift control device 10 mounted together with brake lever assembly 9. As shown in Figure 2, shift control device 10 includes a housing 12 mounted around the handlebar 8, a rotatable handgrip 16 structured for rotation around an axis X coaxial with handlebar 8, a pulley 21 for pulling and releasing an inner wire 11a of control cable 11, and a pulley retaining member 28 for retaining pulley 21 to housing 12. Pulley retaining-member 28 may include a framed opening 28a for selectively displaying a numeral disposed on pulley 21 indicating the currently selected gear. Brake lever assembly 9 includes a brake lever 9a pivotably mounted to a brake lever bracket 9b which, in tum, is mounted around handlebar 8 in close proximity to (e.g., adjacent) housing 12 of shift control device 10. Brake lever 9a is connected to a brake control cable 9c for controlling a brake device in a conventional manner. Figure 3 is an exploded view of a portion of shift control device 10 illustrating housing 12, a clamping unit 13 used to fasten shift control device 10 to handlebar 8, pulley 21, and pulley retaining member 28 in more detail. As shown in Figure 3, clamping unit 13 comprises a collar-shaped clamp member 13a structured to mount around handlebar 8, a clamp arm member 13b coupled to clamp member 13a and extending in a radial direction from clamp member 13a, and a housing mounting member 13c disposed on clamp arm member 13b and spaced apart from clamp member 13a for mounting a portion of housing 12 to clamping unit 13. In this embodiment, housing mounting member 13c is laterally offset from a lateral edge 13h of clamp arm member 13b. This allows brake bracket 9b to be mounted more ergonomically and compactly adjacent to shift control device 10 by fitting brake bracket 9b in the recess formed by the offset housing mounting member 13c and the lateral edge 13h of clamp arm member 13b. Clamp member 13a includes a fastening flange 13f defining a first fastener opening 13g for receiving a clamping fastener 25 therethrough, and clamp arm member 13b includes a second fastener opening 13d aligned with first fastener opening 13g for receiving clamping fastener 25 therethrough. When housing 12 is assembled to clamping unit 13, clamping fastener 25 also extends through an opening 12f in housing 12, and a threaded portion 25a of clamping fastener 25 engages a threaded nut 12g. Tightening clamping fastener 25 with nut 12g causes fastening flange 13f to move toward clamp arm member 13b, thus tightening clamp member 13a to handlebar 8. Housing 12 includes a generally annular base member 12a structured to mount around handlebar 8, a housing arm member 12j coupled to base member 12a and extending in the direction of the clamp arm member 13b (e.g., extending along clamp arm member 13b), and a pulley coupling member 12b having a generally flat surface 12k disposed on housing arm member 12j and spaced apart from base member 12a. A pulley shaft 12c having a shaft opening 12h extends from surface 12k, and pulley 21, which has a central opening 21c, is rotatably mounted around pulley shaft 12c for rotation around an axis Y that is oriented differently (e.g., perpendicular) relative to the handlebar axis X. Pulley retaining member 28 has an opening 28c that is shaped to nonrotatably mount pulley retaining member around pulley shaft 12c. Pulley 21 and pulley retaining member 28 are retained on pulley shaft 12c by a pulley fastener 22 and washer 22a. Pulley fastener 22 extends through shaft opening 12h into a threaded opening 13k defined by housing mounting member 13c so that pulley fastener 22 also fastens pulley coupling member 12b to housing mounting member 13c. Threaded opening 13k is located in the offset portion of housing mounting member 13c so that brake lever bracket 9b may be positioned approximately below opening 13k. A cable interface member 12e abuts against a cable mounting flange 12d formed on pulley coupling member 12b, and a cable adjusting barrel 12m for receiving outer casing 11b of transmission control cable 11 passes through cable interface member 12e and screws into cable mounting flange 12d. A resistance enhancing spring 12p is disposed between cable adjusting barrel 12m and cable interface member 12e to press cable interface member 12e againstcable mounting flange 12d and prevent inadvertent movement of cable adjusting barrel 12m. Cable adjusting barrel 12m operates in awell known mannerto adjust the tension on innercable 11a. Figures 4A-4E illustrate the structure of a pulley 21 according to the invention in more detail. Pulley 21 includes a pulley body 21k having an outer peripheral surface 21m and a central opening 21 c for receiving pulley shaft 12c therethrough. A first winding groove 21e is formed into the outer peripheral surface 21 m for winding a first transmission element in the form of a connecting cable 23 (Figure 3), and a second winding groove 21d is formed into the outer peripheral surface 21m for winding a second transmission element in the form of inner wire 11a of transmission control cable 11. As seen more specifically in Figure 4C, the path of the first winding groove 21e is inclined relative to the path of the second winding groove 21d in the circumferential direction of the outersurface. More specifically, firstwinding groove 21e includes a first groove segment 21x that is inclined relative to second winding groove 21d and a second groove segment 21y that is parallel to the second winding groove 21d. In this embodiment, first winding groove 21e additionally has a varying radius of curvature L2 as shown In Figure 4E, whereas second winding groove 21d has a constant radius of curvature L1 as shown in Figure 4D. Alternatively, second winding groove 21d may have a varying radius of curvature as shown in Fig-ure 4F. Of course, first winding groove 21e may have a constant radius of curvature if desired in some applications. Second winding groove 21d lies completely within a rotation plane P perpendicular to axis Y (in which case first winding groove 21e is inclined relative to rotation plane P), but of course that is not necessary. Pulley 21 further includes a first transmission element fixing portion in the form of a generally cylindrical opening 21b for seating a terminating nipple 23b attached to the end of cable 23, and a second transmission element fixing portion in the form of a generally cylindrical opening 21a for seating a terminating nipple 11b attached to the end of inner wire 11a. In this embodiment, cylindrical openings 21a and 21b are located in close proximity to outer peripheral surface 21m, and they are spaced apart from each other in the peripheral direction of the pulley body 21k. A cable passage 21b' extends from opening 21b through a side of pulley body 21k to facilitate placement of termination nipple 23b in opening 21b. Opening 21a a has a longitudinal opening axis R that is generally tangent to groove 21d, and opening 21b has a longitudinal axis S that extends generally parallel to rotational axis Y. These structures combine to provide a pulley that is thinner than prior art pulleys. Figure 5 is an exploded view of an indexing mechanism used in shift control device 10. As shown in Figure 5, shift control device 10 further includes a fixed member 15 for attaching to handlebar 8 in such a way that it cannot rotate in relation to handlebar 8; rotatable handgrip 16, with gripping protrusions 16h' capable of rotating around the handlebar axis X on fixed member 15; an intermediate element 17 (called "an idler") that meshes with both the fixed member 15 and the rotatable handgrip 16, that can rotate around the handlebar axis X, and that can move along the handlebar axis X; and a takeup member 18 that remains in constant gear engagement with the intermediate element 17, and can thus rotate integrally with intermediate element 17. The general theory of operation (and numbering) of these components is the same as the indexing mechanism described in U.S. patent application number 08/854,520 filed May 12,1997 entitled "Bicycle Shift Control Device" by Takuro Yamane. This embodiment of an indexing mechanism differs from the embodiment shown in that patent application in that a terminating nipple 23a attached to the opposite end of con necting cable 23 is fitted within a generally cylindrical opening 182 in takeup member 18, there are fewer serrations 172 and teeth 181, and there is a coupling hole 15d in fixed member 15 for coupling to a coupling abutment 12k in base member 12. Otherwise the components are structured and operate the same, so a further description of these components is omitted. While the above is a description of various embodiments of the present invention, further modifications may be employed but the scope of the invention is determined by the following claims.

Claims: A pulley (21) for a bicycle shift control device compnsing: a pulley body (21k) having a circular cylindrical outer circumferential surface (21m) and, referred to the circular cylindrical outer circumferential surface (21m), a central opening (21c) for receiving a pulley shaft (12c) therethrough defining a rotational axis; a first winding groove (21e) formed into the outer circumferential surface (21m) for winding a first transmission element (23) thereon; a second winding groove (21d) formed into the outer circumferential surface (21m) for winding a second transmission element physically different from the first transmission element (23) (11a) thereon; and wherein the path of the first winding groove (21e) is at least partly inclined relative to the path of the second winding groove (21d) in circumferential direction of the outer surface (21m) of the pulley (21), i.e. with respect to a plane perpendicular to the rotational axis. The pulley according to claim 1, characterized in that the first winding groove (21e) includes: a first groove segment (21x) that is inclined relative to the second winding groove (21d); and a second groove segment (21y) that is parallel to the second winding groove (21d). The pulley according to claim 1, characterized in that the second winding groove (21d) is oriented perpendicular to the rotational axis, i.e. lies in a plane perpendicular to the rotational axis. The pulley according to claim 3, characterized in that the entire second winding groove (21d) is oriented perpendicular to the rotational axis. The pulley according to any of the preceding claims, characterized in that the pulley includes: a first transmission element fixing portion (21b) for fixing an end of the first transmission element (23b); and a second transmission element fixing portion (21a) for fixing an end of the second transmission element (11b). The pulley according to claims 5 characterized in that the first transmission element fixing portion (21b) is located in close proximity to the outer peripheral surface (21m), and wherein the second transmission element fixing portion (21a) is located in close proximity to the outer peripheral surface (21m). The pulley according to claim 5 or 6 characterized in that the first transmission element fixing portion (21b) is spaced apart from the second transmission element fixing portion (21a) in the peripheral direction of the pulley body (21k). The pulley according to one of claims 5 to 7, characterized in that the pulley body (21k) defines a generally cylindrical first opening for forming the first transmission element fixing portion (21b), wherein the first opening has a longitudinal first opening axis that extends in the direction of the rotational axis. The pulley according to one of claims 5 to 8, characterized in that the pulley body (21k) defines a generally cylindrical second opening for forming the second transmission element fixing portion (21a), wherein the second opening has a longitudinal second opening axis that is generally tangent to the second groove. The pulley according to any of claims 1 to 9, characterized in that the first winding groove (21e) has a constant radius of curvature. The pulley according to any of claims 1 to 9, characterized in that the first winding groove (21e) has a varying radius of curvature. A bicycle shift device comprising: a rotatable handgrip (16) structured to rotate around a first axis coaxial with a handlebar (8); a pulley (21) operatively coupled to the handgrip (16) for rotation in a rotation plane around a rotational axis in response to rotation of the handgrip (16), wherein the pulley (21) includes: a pulley body (21k) having an outer circumferential surface (21m); a first winding groove (21e) formed into the outer peripheral surface (21m) for winding a first transmission element (23) thereon; a second winding groove (21d) formed into the outer circumferential surface (21m) for winding a second transmission element physically different from the first transmission element (11a) thereon; and wherein the path of the first winding groove (21e) is at least partly inclined relative to the path of the second winding groove (21d) in circumferential direction of the outer surface (21m) of the pulley (21), i.e. with respect to a plane perpendicular to the rotational axis of the pulley. The device according to claim 12, characterized in that the first winding groove (21e) has a constant radius of curvature. The device according to claim 12, characterized in that the first winding groove (21e) has a varying radius of curvature. The device according to one of claims 12 to 14, characterized in that the first axis is oriented differently from the rotational axis. The device according to one of claims 12 to 15, characterized In that it further comprises a flexible transmission element (23) coupled between the pulley (21) and the handgrip (16) for transmitting rotation of the handgrip (16) to the pulley (21), wherein the transmission element (23) winds around the first winding groove (21e). The device according to claim 16, characterized in that it further comprises a winding member (13) operatively coupled to the handgrip (16) for rotation around the first axis in response to rotation of the handgrip (16), wherein the winding member includes a third winding groove, and wherein the transmission element (23) is coupled to the winding member and winds around the third winding groove. The device according to one of claims 12-17, characterized in that the first winding groove (21e) includes: a first groove segment (21x) that is inclined relative to the second winding groove (21d); and a second groove segment (21y) that is parallel to the second winding groove (21d). The device according to claim 18, characterized in that the second winding groove (21d) lies in a plane perpendicular to the rotational axis. The device according to claim 19, characterized in that the entire second winding groove (21d) lies in a plane perpendicular to the rotational axis. The device according to claim 16, characterized in that the pulley (21) includes: a first transmission element fixing portion (21b) for fixing an end of a first transmission element (23b); and a second transmission element fixing portion (21a) for fixing an end of a second transmission element (11b), wherein the second transmission element fixing portion (21a) is located in close proximity to the outer circumferential surface (21m). The device according to claim 21, characterized In that the first transmission element fixing portion (21b) is located In close proximity to the outer circumferential surface (21m), and wherein the second transmission element fixing portion (21a) is located in close proximity to the outer circumferential surface (21m). The device according to claim 21 or 22, characterized in that the first transmission element fixing portion (21b) is spaced apart from the second transmission element fixing portion (21a) in the circumferential direction of the.pulley body (21). The device according to any of claims 21 to 23, characterized in that the pulley body (21k) defines a generally cylindrical first opening for forming the first transmission element fixing portion (21b), wherein the first opening has a longitudinal first opening axis that extends in the direction of the rotational axis. The device according to any of claims 21 to 24 characterized in that the pulley body (21k) defines a generally cylindrical second opening, for forming the second transmission element fixing portion (21a), wherein the second opening has a longitudinal second opening axis that is generally tangent to the second groove.

Inventors: OSE KENJI, OSE, KENJI
Applicants: SHIMANO KK, SHIMANO INC.
Application year: 1998
Main classification: B62K23
IPC codes: B62M25, B62K23