Title: Assisting apparatus for changing speeds in a bicycle transmission
Abstract: An assisting apparatus for using power from a rotating member to assist the operation of a bicycle transmission includes a mounting unit; an input transmission member coupled to the mounting unit, wherein the input transmission member moves to at least a neutral position, to an upshift position and to a downshift position; and an output transmission member coupled to the mounting unit, wherein the output transmission member moves to at least a first output position and a second output position. A rotating member engaging member moves between a rotating member engaging position and a rotating member disengaging position, and a motion transmitting mechanism transmits motion from the rotating member engaging member to the output transmission member. A switching mechanism moves the rotating member engaging member to the rotating member engaging position when the input transmission member is in at least one of the upshift position and the downshift position.
Patent Number: 6,868,752 Issued on 03/22/2005 to Tetsuka, et al.
| Inventors:
|
Tetsuka; Toshio (Sakai, JP);
Kanehisa; Takanori (Sakai, JP);
Tabe; Koshi (Sakai, JP);
Hino; Tetsuya (Shimonoseki, JP);
Watarai; Etsuyoshi (Izumi, JP);
Shahana; Satoshi (Osaka, JP)
|
| Assignee:
|
Shimano, Inc. (Sakai, JP)
|
| Appl. No.:
|
190461 |
| Filed:
|
July 5, 2002 |
| Current U.S. Class: |
74/502.2; 474/80; 74/489 |
| Intern'l Class: |
F16C 001//10 |
| Field of Search: |
474/80
74/502.2,501.6,473.14,527,502.4,594.6,473.16,535,526,500.5,502.6
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Bucci; David A.
Assistant Examiner: Van Pelt; Bradley J.
Attorney, Agent or Firm: Deland; James A.
Claims
What is claimed is:
1. An assisting apparatus for using power from a rotating member to assist
the operation of a bicycle transmission comprising:
a mounting unit;
an input transmission member coupled to the mounting unit, wherein the
input transmission member moves to at least a neutral position, to an
upshift position and to a downshift position;
an output transmission member coupled to the mounting unit, wherein the
output transmission member moves to at least a first output position and a
second output position;
a rotating member engaging member that moves between a rotating member
engaging position and a rotating member disengaging position;
a motion transmitting mechanism for transmitting motion from the rotating
member engaging member to the output transmission member; and
a switching mechanism that moves the rotating member engaging member to the
rotating member engaging position when the input transmission member is in
at least one of the upshift position and the downshift position.
2. The apparatus according to claim 1 wherein the motion transmitting
mechanism comprises:
a drive tooth that moves integrally with the output transmission member;
a motion transmitting member coupled to the rotating member engaging
member; and
a pawl coupled to the motion transmitting member, wherein the pawl engages
the drive tooth to transmit motion from the rotating member engaging
member to the output transmission member.
3. The apparatus according to claim 1 wherein the motion transmitting
mechanism comprises a motion transmitting member rotatably supported
relative to the mounting member, wherein the motion transmitting member
moves between a switch on position and a switch off position.
4. The apparatus according to claim 3 wherein the switching mechanism
comprises a drive control mechanism that ordinarily maintains the motion
transmitting member in the switch off position.
5. The apparatus according to claim 4 wherein the drive control mechanism
comprises:
an input control member; and
a switch on drive control member that moves between a motion transmitting
member engaging position and a motion transmitting member disengaging
position in response to movement of the input control member, wherein the
motion transmitting member engaging position maintains the motion
transmitting member in the switch off position, and wherein the motion
transmitting member disengaging position allows the motion transmitting
member to move toward the switch on position.
6. The apparatus according to claim 5 wherein the input control member
includes a cam surface that moves the switch on drive control member
between the motion transmitting member engaging position and the motion
transmitting member disengaging position.
7. The apparatus according to claim 6 wherein the input control member is
rotatably supported relative to the mounting unit.
8. The apparatus according to claim 7 further comprising a biasing
component that biases the motion transmitting member toward the switch on
position.
9. The apparatus according to claim 3 wherein the motion transmitting
member rotates in one of a clockwise direction and a counterclockwise
direction when rotating from the switch off position toward the switch on
position, and wherein the motion transmitting member rotates in the other
one of the clockwise direction and the counterclockwise direction when the
motion transmitting mechanism transmits motion from the rotating member
engaging member to the output transmission member.
10. The apparatus according to claim 9 wherein the rotating member engaging
member is coupled to the motion transmitting member, and wherein the
switching mechanism comprises:
a rotating member engaging member control cam; and
a cam follower coupled to the rotating member engaging member so that the
cam follower causes the rotating member engaging member to move to the
rotating member engaging position when the motion transmitting member
moves toward the switch on position.
11. The apparatus according to claim 9 wherein the motion transmitting
member rotates in the one of the clockwise direction and the
counterclockwise direction toward the switch off position after the motion
transmitting mechanism transmits motion from the rotating member engaging
member to the output transmission member.
12. The apparatus according to claim 11 wherein the switching mechanism
comprises a drive control mechanism that inhibits rotation of the motion
transmitting member to the switch on position after the motion
transmitting mechanism transmits motion from the rotating member engaging
member to the output transmission member.
13. The apparatus according to claim 12 wherein the drive control mechanism
comprises:
an input control member; and
a switch off drive control member that moves between a motion transmitting
member engaging position and a rotating member disengaging position in
response to movement of the input control member, wherein the rotating
member engaging position maintains the motion transmitting member in a
pause position after the motion transmitting mechanism transmits motion
from the rotating member engaging member to the output transmission
member, and wherein the motion transmitting member disengaging position
allows the motion transmitting member to continue rotating in the one of
the clockwise direction and the counterclockwise direction.
14. The apparatus according to claim 13 wherein the input control member
includes a cam surface that moves the switch off drive control member
between the motion transmitting member engaging position and the motion
transmitting member disengaging position.
15. The apparatus according to claim 14 wherein the input control member is
rotatably supported relative to the mounting unit.
16. The apparatus according to claim 15 wherein the drive control mechanism
ordinarily maintains the motion transmitting member in a switch off
position.
17. The apparatus according to claim 16 wherein the drive control mechanism
further comprises:
a switch on drive control member that moves between a motion transmitting
member engaging position and a rotating member disengaging position in
response to movement of the input control member, wherein the motion
transmitting member engaging position maintains the motion transmitting
member in the switch off position, and wherein the motion transmitting
member disengaging position allows the motion transmitting member to move
toward the switch on position.
18. The apparatus according to claim 17 wherein the cam surface moves the
switch on drive control member between the motion transmitting member
engaging position and the motion transmitting member disengaging position.
19. The apparatus according to claim 1 further comprising:
a position maintaining mechanism including a position maintaining member
that moves between a position maintaining position and a position release
position, wherein the position maintaining position maintains the output
transmission member in one of the first output position and the second
output position, and wherein the position release position allows the
output transmission member to move toward the other one of the first
output position and the second output position;
a release drive member coupled to the mounting unit, wherein the release
drive member moves between at least a first release drive position and a
second release drive position;
a release control mechanism including a release member that moves from a
first release member position toward a second release member position when
the release drive member moves from the first release drive position
toward the second release drive position, wherein the release control
mechanism moves the position maintaining member to the position release
position as the release member moves toward the second release member
position and allows the position maintaining member to return to the
position maintaining position as the release member continues to move
toward the second release member position.
20. The apparatus according to claim 19 wherein the release control
mechanism further comprises a cam member coupled to the release member,
wherein the cam member moves the position maintaining member to the
position release position as the release member moves toward the second
release member position and allows the position maintaining member to
return to the position maintaining position as the release member
continues to move toward the second release member position.
21. The apparatus according to claim 20 wherein the release member
rotatably supports the cam member.
22. The apparatus according to claim 21 wherein the position maintaining
mechanism comprises:
a positioning tooth that moves integrally with the output transmission
member; and
a positioning pawl that engages the positioning tooth.
23. The apparatus according to claim 22 wherein the release control
mechanism further comprises a cam follower coupled to the positioning
pawl.
24. The apparatus according to claim 23 wherein the cam follower comprises
a roller.
25. The apparatus according to claim 24 wherein the release member
comprises a release plate, and wherein the cam member comprises a cam
plate having a first end pivotably mounted to the release plate and a
second end defining a cam lobe that contacts the roller such that the cam
plate rotates as the release plate moves toward the second release member
position.
26. The apparatus according to claim 25 wherein the motion transmitting
mechanism comprises:
a motion transmitting member coupled to the rotating member engaging
member;
a drive tooth that moves integrally with the output transmission member;
and
a motion transmitting pawl coupled to the motion transmitting member,
wherein the motion transmitting pawl engages the drive tooth to transmit
motion from the rotating member engaging member to the output transmission
member.
27. The apparatus according to claim 26 wherein the release drive member
comprises the motion transmitting member.
28. The apparatus according to claim 20 wherein the cam member comprises a
plurality of cam teeth.
29. The apparatus according to claim 28 wherein the cam member is rotatably
supported relative to the mounting unit.
30. The apparatus according to claim 29 wherein the cam member comprises a
cam wheel, and wherein the plurality of cam teeth are circumferentially
disposed around the cam wheel.
31. The apparatus according to claim 30 wherein the position maintaining
mechanism comprises:
a positioning tooth that moves integrally with the output transmission
member; and
a positioning pawl that engages the positioning tooth.
32. The apparatus according to claim 31 wherein the release control
mechanism further comprises a cam follower supported by the position
maintaining pawl for contacting the plurality of cam teeth.
33. The apparatus according to claim 32 further comprising:
a cam drive tooth supported by the cam wheel; and
a cam drive pawl supported by the release member for engaging the cam drive
tooth.
34. The apparatus according to claim 33 wherein the output transmission
member is rotatably supported relative to the mounting unit, and wherein
the cam wheel rotates coaxially with the output transmission member.
35. The apparatus according to claim 34 wherein the cam follower comprises
a roller.
36. The apparatus according to claim 35 wherein the motion transmitting
mechanism comprises:
a motion transmitting member coupled to the rotating member engaging
member;
a drive tooth that moves integrally with the output transmission member;
and
a motion transmitting pawl coupled to the motion transmitting member,
wherein the motion transmitting pawl engages the drive tooth to transmit
motion from the rotating member engaging member to the output transmission
member.
37. The apparatus according to claim 36 wherein the release drive member
comprises the motion transmitting member.
38. The apparatus according to claim 32 further comprising:
a cam drive tooth supported by the cam wheel; and
a cam drive pawl supported by the release member for engaging the cam drive
tooth.
39. The apparatus according to claim 38 wherein the output transmission
member is rotatably supported relative to the mounting unit, and wherein
the cam wheel rotates coaxially with the output transmission member.
40. The apparatus according to claim 39 wherein the cam follower comprises
a roller.
41. The apparatus according to claim 40 wherein the apparatus is adapted to
be used in an assisting apparatus for using power from a rotating member
to assist the operation of a bicycle transmission, and wherein the
apparatus further comprises:
a rotating member engaging member that moves between a rotating member
engaging position and a rotating member disengaging position; and
a motion transmitting mechanism for transmitting motion from the rotating
member engaging member to the output transmission member.
42. The apparatus according to claim 41 wherein the motion transmitting
mechanism comprises a motion transmitting member rotatably supported
relative to the mounting member, wherein the motion transmitting member
moves between a switch on position and a switch off position.
43. The apparatus according to claim 42 wherein the release drive member
comprises the motion transmitting member.
44. An assisting apparatus for using power from a rotating member to assist
the operation of a bicycle transmission comprising:
a mounting unit;
an input transmission member coupled to the mounting unit, wherein the
input transmission member moves between at least a first input position
and a second input position;
an output transmission member coupled to the mounting unit, wherein the
output transmission member moves between at least a first output position
and a second output position;
a rotating member engaging member that moves between a rotating member
engaging position and a rotating member disengaging position;
a motion transmitting mechanism for transmitting motion from the rotating
member engaging member to the output transmission member; and
a switching mechanism that moves the rotating member engaging member to the
rotating member engaging position when the input transmission member is in
the second input position, and that prevents the rotating member engaging
member from returning to the rotating member engaging position after the
motion transmitting mechanism transmits motion from the rotating member
engaging member to the output transmission member until the input
transmission member moves away from the second input position.
45. The apparatus according to claim 44 wherein the motion transmitting
mechanism comprises a motion transmitting member rotatably supported
relative to the mounting member, wherein the motion transmitting member
moves between a switch on position and a switch off position.
46. The apparatus according to claim 45 wherein the motion transmitting
member rotates in one of a clockwise direction and a counterclockwise
direction when rotating from the switch off position toward the switch on
position, and wherein the motion transmitting member rotates in the other
one of the clockwise direction and the counterclockwise direction when the
motion transmitting mechanism transmits motion from the rotating member
engaging member to the output transmission member.
47. The apparatus according to claim 46 wherein the rotating member
engaging member is coupled to the motion transmitting member, and wherein
the switching mechanism comprises:
a rotating member engaging member control cam; and
a cam follower coupled to the rotating member engaging member so that the
cam follower causes the rotating member engaging member to move to the
rotating member engaging position when the motion transmitting member
moves toward the switch on position.
48. The apparatus according to claim 46 wherein the motion transmitting
member rotates in the one of the clockwise direction and the
counterclockwise direction toward the switch off position after the motion
transmitting mechanism transmits motion from the rotating member engaging
member to the output transmission member.
49. The apparatus according to claim 48 wherein the switching mechanism
comprises a drive control mechanism that inhibits rotation of the motion
transmitting member to the switch on position after the motion
transmitting mechanism transmits motion from the rotating member engaging
member to the output transmission member.
50. The apparatus according to claim 49 wherein the drive control mechanism
comprises:
an input control member; and
a switch off drive control member that moves between a motion transmitting
member engaging position and a rotating member disengaging position in
response to movement of the input control member, wherein the rotating
member engaging position maintains the motion transmitting member in a
pause position after the motion transmitting mechanism transmits motion
from the rotating member engaging member to the output transmission
member, and wherein the motion transmitting member disengaging position
allows the motion transmitting member to continue rotating in the one of
the clockwise direction and the counterclockwise direction.
51. The apparatus according to claim 50 wherein the input control member
includes a cam surface that moves the switch off drive control member
between the motion transmitting member engaging position and the motion
transmitting member disengaging position.
52. The apparatus according to claim 51 wherein the input control member is
rotatably supported relative to the mounting unit.
53. The apparatus according to claim 52 wherein the rotating member
engaging member is coupled to the motion transmitting member, and wherein
the switching mechanism comprises:
a rotating member engaging member control cam; and
a cam follower coupled to the rotating member engaging member so that the
cam follower causes the rotating member engaging member to move to the
rotating member engaging position when the motion transmitting member
moves toward the switch on position.
54. A bicycle control device comprising:
a mounting unit;
an output transmission member coupled to the mounting unit, wherein the
output transmission member moves between at least a first output position
and a second output position;
a position maintaining mechanism including a position maintaining member
that moves between a position maintaining position and a position release
position, wherein the position maintaining position maintains the output
transmission in one of the first output position and the second output
position, and wherein the position release position allows the output
transmission member to move toward the other one of the first output
position and the second output position;
a release drive member coupled to the mounting unit, wherein the release
drive member moves between at least a first release drive position and a
second release drive position;
a release control mechanism including a release member that moves from a
first release member position toward a second release member position when
the release drive member moves from the first release drive position
toward the second release drive position, wherein the release control
mechanism moves the position maintaining member to the position release
position as the release member moves toward the second release member
position and allows the position maintaining member to return to the
position maintaining position as the release member continues to move
toward the second release member position.
55. The apparatus according to claim 54 wherein the release control
mechanism further comprises a cam member coupled to the release member,
wherein the cam member moves the position maintaining member to the
position release position as the release member moves toward the second
release member position and allows the position maintaining member to
return to the position maintaining position as the release member
continues to move toward the second release member position.
56. The apparatus according to claim 55 wherein the release member
rotatably supports the cam member.
57. The apparatus according to claim 56 wherein the position maintaining
mechanism comprises:
a positioning tooth that moves integrally with the output transmission
member; and
a positioning pawl that engages the positioning tooth.
58. The apparatus according to claim 57 wherein the release control
mechanism further comprises a cam follower coupled to the positioning
pawl.
59. The apparatus according to claim 58 wherein the cam follower comprises
a roller.
60. The apparatus according to claim 59 wherein the release member
comprises a release plate, and wherein the cam member comprises a cam
plate having a first end pivotably mounted to the release plate and a
second end defining a cam lobe that contacts the roller such that the cam
plate rotates as the release plate moves toward the second release member
position.
61. The apparatus according to claim 60 wherein the apparatus is adapted to
be used in an assisting apparatus for using power from a rotating member
to assist the operation of a bicycle transmission, and wherein the
apparatus further comprises:
a rotating member engaging member that moves between a rotating member
engaging position and a rotating member disengaging position; and
a motion transmitting mechanism for transmitting motion from the rotating
member engaging member to the output transmission member.
62. The apparatus according to claim 61 wherein the motion transmitting
mechanism comprises a motion transmitting member rotatably supported
relative to the mounting member, wherein the motion transmitting member
moves between a switch on position and a switch off position.
63. The apparatus according to claim 62 wherein the release drive member
comprises the motion transmitting member.
64. The apparatus according to claim 55 wherein the cam member comprises a
plurality of cam teeth.
65. The apparatus according to claim 64 wherein the cam member is rotatably
supported relative to the mounting unit.
66. The apparatus according to claim 65 wherein the cam member comprises a
cam wheel, and wherein the plurality of cam teeth are circumferentially
disposed around the cam wheel.
67. The apparatus according to claim 66 wherein the position maintaining
mechanism comprises:
a positioning tooth that moves integrally with the output transmission
member; and
a positioning pawl that engages the positioning tooth.
68. The apparatus according to claim 67 wherein the release control
mechanism further comprises a cam follower supported by the positioning
pawl for contacting the plurality of cam teeth.
Description
BACKGROUND OF THE INVENTION
The present invention is directed to bicycle transmissions and, more
particularly, to an apparatus for assisting a change speed operation in
the bicycle transmission.
Various devices have been developed to help reduce the effort needed to
operate bicycle transmissions such as derailleurs and internal hub
transmissions. Examples of such devices particularly suited to assist the
operation of derailleur transmissions are shown in U.S. Pat. No.
5,358,451. The devices shown therein for assisting the operation of a rear
derailleur employ multiple moving parts that are in constant motion, thus
increasing the amount of moving mass as well as the possibility of
premature wear on the components. Devices shown therein for assisting the
operation of a front derailleur accommodate only two front sprockets.
However, many bicycles have more than two front sprockets. Thus, there is
a desire for an assist device that can be used with more than two
sprockets.
Many shift control devices also have been developed to control the
operation of bicycle transmissions. Such shift control devices ordinarily
take the form of levers or cylindrical twist-grips that rotate to a
different position for each gear position. Some shift control devices used
with electrically operated transmissions have the form of buttons that are
pressed by the rider. A lever that rotates to different positions requires
the rider to reach to a different position for each gear in order to
operate the lever, and this can be distracting during high performance
riding. A twist grip does not produce such variable positioning, but the
twist grip must be encircled by the hand to be operated, thus requiring a
substantial amount of effort. Buttons have the disadvantage of being
counterintuitive, and they require more effort to locate.
SUMMARY OF THE INVENTION
The present invention is directed to various features of an apparatus for
assisting a speed change operation in a bicycle transmission. Like prior
art devices, the apparatus can accommodate two front sprockets, but the
apparatus also can accommodate more than two front sprockets. The
apparatus also provides a shift control device that is easy to operate in
an intuitive manner.
In one feature of the present invention, an assisting apparatus for using
power from a rotating member to assist the operation of a bicycle
transmission includes a mounting unit; an input transmission member
coupled to the mounting unit, wherein the input transmission member moves
to at least a neutral position, to an upshift position and to a downshift
position; and an output transmission member coupled to the mounting unit,
wherein the output transmission member moves to at least a first output
position and a second output position. A rotating member engaging member
moves between a rotating member engaging position and a rotating member
disengaging position, and a motion transmitting mechanism transmits motion
from the rotating member engaging member to the output transmission
member. A switching mechanism moves the rotating member engaging member to
the rotating member engaging position when the input transmission member
is in at least one of the upshift position and the downshift position.
In another feature of the present invention, an assisting apparatus for
using power from a rotating member to assist the operation of a bicycle
transmission comprises a mounting unit; an input transmission member
coupled to the mounting unit, wherein the input transmission member moves
between at least a first input position and a second input position; and
an output transmission member coupled to the mounting unit, wherein the
output transmission member moves between at least a first output position
and a second output position. A rotating member engaging member moves
between a rotating member engaging position and a rotating member
disengaging position, and a motion transmitting mechanism transmits motion
from the rotating member engaging member to the output transmission
member. A switching mechanism moves the rotating member engaging member to
the rotating member engaging position when the input transmission member
is in the second input position, moves the rotating member engaging member
to the rotating member disengaging position when the output transmission
member moves from the first output position to the second output position,
and prevents the rotating member engaging member from returning to the
rotating member engaging position until the input transmission member
moves away from the second input position. This feature has many
advantages, such as allowing the apparatus to be operated to produce a
single speed change without requiring the rider to move the input
transmission member back to the home position.
In another feature of the present invention which can be used in
environments other than those which use power from a rotating member to
assist the operation of a bicycle transmission, a bicycle control device
includes a mounting unit; an output transmission member coupled to the
mounting unit, wherein the output transmission member moves between at
least a first output position and a second output position; a position
maintaining mechanism including a position maintaining member that moves
between a position maintaining position and a position release position,
wherein the position maintaining position maintains the output
transmission in one of the first output position and the second output
position, and wherein the position release position allows the output
transmission member to move toward the other one of the first output
position and the second output position; a release drive member coupled to
the mounting unit, wherein the release drive member moves between at least
a first release drive position and a second release drive position; and a
release control mechanism including a release member that moves from a
first release member position toward a second release member position when
the release drive member moves from the first release drive position
toward the second release drive position, wherein the release control
mechanism moves the position maintaining member to the position release
position as the release member moves toward the second release member
position and allows the position maintaining member to return to the
position maintaining position as the release member continues to move
toward the second release member position.
In another feature of the present invention, a shift control device is
provided for controlling a transmission control member coupled to a
bicycle transmission. The device comprises an actuating component that is
manually operated by a rider, wherein the actuating component moves to an
actuating component neutral position, to an actuating component upshift
position and to an actuating component downshift position. A first biasing
component biases the actuating component toward one of the upshift
position and the downshift position, and a neutral positioning component
positions the actuating component in a neutral position. A transmission
control member coupling component is adapted to couple the transmission
control member to the actuating component such that the transmission
control member moves to a transmission control member neutral position
when the actuating component moves to the actuating component neutral
position, to a transmission control member upshift position when the
actuating component moves to the actuating component upshift position, and
to a transmission control member downshift position when the actuating
component moves to the actuating component downshift position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a particular embodiment of a bicycle that
incorporates an apparatus according to the invention for assisting a speed
change operation in a bicycle transmission;
FIG. 2 is a more detailed view of the shift control device;
FIG. 3 is an exploded view of the shift control device shown in FIG. 2;
FIGS. 4(A)-4(C) are schematic views showing the operation of the shift
control device;
FIG. 5 is a closer view of the assist mechanism shown in FIG. 1;
FIG. 6 is an exploded view of a particular embodiment of an input unit
according to the present invention;
FIG. 7 is a view of the assist mechanism showing a particular embodiment of
a rotating member engaging unit;
FIG. 8 is a rear cross sectional view of the assist mechanism;
FIGS. 9(A)-9(D) illustrate the operation of the rotating member engaging
member;
FIG. 10 is an enlarged cross sectional view of the internal components of
the positioning unit shown in FIG. 8;
FIG. 11 is a side view of a particular embodiment of a motion transmitting
member according to the present invention;
FIG. 12 is a side view of a particular embodiment of an input transmission
member according to the present invention;
FIG. 13 is a side view of a particular embodiment of a middle plate
according to the present invention;
FIG. 14 is a side view of a particular embodiment of a positioning member
according to the present invention;
FIG. 15 is a perspective view of a particular embodiment of a motion
transmitting pawl according to the present invention;
FIGS. 16(A)-(E) are views illustrating the operation of the assist
mechanism in an upshifting direction;
FIGS. 17(A)-(F) are views illustrating the operation of the assist
mechanism in a downshifting direction;
FIGS. 18(A) and 18(B) are views illustrating the cooperation of the motion
transmitting pawl with the middle plate during a downshifting operation;
FIGS. 19(A) and 19(B) are views of an alternative embodiment of a drive
control mechanism according to the present invention; and
FIG. 20 is a side view of an alternative embodiment of a release mechanism
according to the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIG. 1 is a side view of a bicycle 10 that incorporates a particular
embodiment of an assist mechanism 14 according to the invention for
assisting a change speed operation in a bicycle transmission. Bicycle 10
may be any type of bicycle, and in this embodiment bicycle 10 includes a
typical frame 18 comprising a top tube 22, a head tube 24, a down tube 26
extending downwardly from head tube 24, a seat tube 30 extending
downwardly from top tube 22, a bottom bracket 32 disposed at the junction
of down tube 26 and seat tube 30, a pair of seatstays 34 extending
rearwardly and downwardly from top tube 22, and a pair of chainstays 38
extending rearwardly from bottom bracket 32. A fork 42 is rotatably
supported within head tube 24, and a front wheel 46 is rotatably supported
to the lower end of fork 42. The rotational direction of fork 42 and wheel
46 is controlled by a handlebar 50 in a well known manner. A rear wheel 54
having a plurality of coaxially mounted freewheel sprockets (not shown) is
rotatably supported at the junction of seatstays 34 and chainstays 38, and
a pedal assembly 58 supporting a plurality of front (chainwheel) sprockets
62 is rotatably supported within bottom bracket 32. In this embodiment,
three front sprockets 62 rotate coaxially and integrally with pedal
assembly 58. A chain 66 engages one of the plurality of front sprockets 62
and one of the plurality of freewheel sprockets mounted to rear wheel 54.
A front derailleur 70 moves chain 66 from one front sprocket 62 to
another, and a rear derailleur 74 moves chain 66 from one freewheel
sprocket to another. Both operations are well known. In this embodiment,
front derailleur 70 is controlled by pulling and releasing an output
control wire 78 coupled to assist mechanism 14, and assist mechanism 14 is
controlled by an inner wire 80 of a Bowden-type control cable 82 connected
to a shift control device 84 mounted to the left side of handlebar 50.
Rear derailleur 74 is controlled by a Bowden-type control cable 86 in a
conventional manner.
FIG. 2 is a view of the left side of handlebar 50 showing shift control
device 84 in more detail, and FIG. 3 is an exploded view of shift control
device 84. In this embodiment, shift control device 84 is mounted between
a stationary handgrip 92 and a conventional brake lever bracket 94 that
supports a brake lever 98. Shift control device 84 comprises a base member
102, a clamping band 106, a biasing component in the form of a spring 110,
an intermediate member 114, an actuating component 118, and a retainer
122. Base member 102 comprises a tubular portion 126 and a flange portion
130. Tubular portion 126 surrounds handlebar 50, and flange portion 130
extends radially outwardly from an inner end of tubular portion 126.
Clamping band 106 has a locking projection 134 and mounting ears 138 and
142, and the structure fits within an annular recess (not shown) with a
locking groove formed at the inner peripheral surface of flange portion
130. A screw 144 extends through an opening 148 in flange portion 130 and
through mounting ears 138 and 142 and screws into a nut 152 disposed in
another opening 153 in flange portion 130 to tighten mounting ears 138 and
142 toward each other and thereby tighten clamping band 106 and fasten
base member 102 to handlebar 50. A conventional screw-type adjustable
control cable coupler 156 is disposed on flange portion 130 for receiving
the outer casing 81 of control cable 82 in a conventional manner.
Diametrically opposed recesses 160 (only one is visible in FIG. 3) having
abutments 160a and 160b are formed at the junction of tubular portion 126
and flange portion 130, and a base member bias engaging component 164 in
the form of a spring hole is formed in flange portion 130. An end 168 of
spring 110 is fitted within spring hole 164.
Intermediate member 114 is rotatably supported on tubular portion 126 of
base member 102 such that spring 110 is disposed between intermediate
member 114 and flange portion 130 of base member 102. Diametrically
opposed projections or stoppers 172 (only one is visible in FIG. 3)
forming abutments 172a and 172b extend axially from the inner end of
intermediate member 114, and a pair of diametrically opposed intermediate
member projections or stoppers 188 forming abutments 188a and 188b extend
radially outwardly from an outer peripheral surface 184 of intermediate
member 114. An end 192 of spring 110 is fitted within a spring opening 194
(which functions as an intermediate member bias engaging component) formed
in one of the stoppers 188 for biasing intermediate member 114 clockwise.
As a result, abutments 172a of stoppers 172 engage abutments 160a (which
function as base member stoppers) to limit the rotation of intermediate
member 114 relative to base member 102.
Actuating component 118 is rotatably supported by intermediate member 114
which, as noted above, is rotatably supported by the tubular portion 126
of base member 102. Thus, actuating component 118 rotates coaxially around
intermediate member 114, tubular portion 126 of base member 102, and
handlebar 50. Actuating component 118 comprises a tubular member 200,
first and second finger projections or levers 204 and 208 extending
radially outwardly from tubular member 200, a transmission control member
coupling component in the form of an opening 212 for receiving a cable end
bead (not shown) attached to the end of inner wire 80 so that inner wire
80 moves integrally with actuating component 114, and diametrically
opposed recesses 216 forming abutments 216a and 216b. In the assembled
state, intermediate member stoppers 188 are fitted within the
corresponding recesses 216 between abutments 216a and 216b so that
abutments 216a and 216b function as actuating member stoppers. In this
embodiment, inner wire 80 of control cable 82 is under tension as a result
of a biasing component disposed in assist apparatus 14. Thus, actuating
component 118 is biased in the counterclockwise direction such that
abutments 188a of intermediate member stoppers 188 engage abutments 216a
to limit the rotation of actuating component 118 relative to intermediate
member 114 and base member 102.
Retainer 122 is fitted around the outer end of tubular member 126 of base
member 102. Retainer 122 includes four recesses 220 that are evenly formed
on a side surface 224 for engaging four locking tabs 228 that extend
radially outwardly from the outer end of tubular portion 126 of base
member 102. Thus, retainer 122 axially fixes actuating component 118 and
intermediate member 114 in place on base member 102.
FIGS. 4(A)-4(C) schematically illustrate the operation of shift control
device 84. FIG. 4(A) shows actuating component 118 in an actuating
component neutral position. In this position, spring 110 biases
intermediate member 114 clockwise (to the right in FIG. 4(A)) so that
abutments 172a of stoppers 172 contact abutments 160a of recesses 160 on
base member 102, and a biasing component (spring) in assist mechanism 14,
indicated by reference number 232, biases actuating component 118
counterclockwise so that abutments 216a of recesses 216 contact abutments
188a of intermediate member stoppers 188. Thus, abutments 160a, 172a, 188a
and 216a (and to some extent springs 110 and 232) function as neutral
positioning components. Since inner wire 80 is directly coupled to
actuating component 118, inner wire 80 likewise is in a transmission
control member neutral position at this time.
Rotating actuating component 118 clockwise from the position shown in FIG.
4(A) against the biasing force of the biasing component 232 in assist
mechanism 14 causes abutments 216b on actuating component 118 to contact
abutments 188b on intermediate member stopper 188 as shown in FIG. 4(B).
Intermediate member 114 remains stationary at this time. In FIG. 4(B),
actuating component 118 is in an actuating component downshift position,
and inner wire 80 is pulled into a transmission control member downshift
position.
Rotating actuating component 118 counterclockwise from the position shown
in FIG. 4(A) causes intermediate member 114 to rotate counterclockwise (to
the left in FIG. 4(C)) against the biasing force of spring 110, since
abutments 216a contact abutments 188a of intermediate member stoppers 188
and spring 110 is ultimately coupled between actuating component 118 and
base member 102. As a result, actuating component 118 is in an actuating
component upshift position, and inner wire 80 is released into a
transmission control member upshift position.
FIG. 5 is a more detailed view of assist mechanism 14. As shown in FIG. 5,
assist mechanism 14 is mounted to bottom bracket 32, and it includes an
input unit 250, a positioning unit 254, and a rotating member engaging
unit 258 with a cover 262. In this embodiment, assist mechanism 14 is used
in conjunction with a crank arm 266 that includes an axle mounting boss
270 having a plurality of crank arm splines 274 that nonrotatably engage a
plurality of axle splines 278 formed on the end of an axle 282 that is
rotatably supported by bottom bracket 32 in a well known manner. A drive
flange 286 extends radially outwardly from axle mounting boss 270 and
supports a pair of diametrically opposed drive members 290. Drive members
290 have the shape of circular tubes that extend perpendicularly from the
side surface 294 of drive flange 286.
FIG. 6 is an exploded view of a particular embodiment of input unit 250.
Input unit 250 includes an input unit mounting member 298, a wire coupling
member 302, spring 232, and an input link 306. Input unit mounting member
298 has a guide channel 310 for inner wire 80, a central axle opening 314
for receiving an axle 318 (FIG. 10) of positioning unit 254 therethrough,
and a pair of diametrically opposed openings 322 (only one opening is
visible in FIG. 6). Wire coupling member 302 includes a wire winding
groove 326 for winding and unwinding inner wire 80, a conventional wire
coupler 330 in the form of a screw 334, a wire retainer 338 and a nut 342
for fixing inner wire 80 to wire coupling member 302, and an axle opening
346 for receiving axle 318 of positioning unit 254. Input link 306
functions to communicate the rotational position of wire coupling member
302 to positioning unit 254, and it includes an axle mounting portion 350
with an axle receiving opening 352, coupling tabs 354, a radially
extending portion 358, and an axially extending coupling portion 362.
Coupling tabs 354 extend axially from axle mounting portion 350, through
openings 322 in input unit mounting member 298, and into corresponding
openings (not shown) in wire coupling member 302 so that wire coupling
member 302 and input link 306 rotate as a unit. Thus, both wire coupling
member 302 and input link 306 will assume neutral, upshift and downshift
positions corresponding to the positions of actuating component 118 of
shift control device 84. Spring 232 has one end 233 mounted to wire
coupling member 302 and another end 234 mounted to input unit mounting
member 298 so that wire coupling member 302 and input link 306 are biased
in the clockwise (wire winding) direction.
FIG. 7 is an oblique view of assist mechanism 14 with cover 262 of rotating
member engaging unit 258 removed, FIG. 8 is a rear cross sectional view of
assist mechanism 14, and FIGS. 9(A)-9(D) illustrate the operation of
rotating member engaging unit 258. As shown in FIGS. 7, 8 and 9(A),
rotating member engaging unit 258 includes a bottom bracket mounting
member 370 with an opening 374 for receiving axle 282 therethrough, an
axially extending side wall 378, a cam plate 382 with a control cam slot
386 attached to side wall 378, and an opening 390 for supporting a lower
pivot shaft 392. One end of a rotating member engaging member 394 has an
arcuate rotating member engaging surface 398 for engaging drive members
290 on crank arm 266. The other end of rotating member engaging member 394
is pivotably connected between a positioning unit interface plate 402 and
a support plate 406 by a pivot shaft 410. A cam follower 414 that engages
a control cam surface 418 formed by cam slot 386 is mounted to rotating
member engaging member 394 in close proximity to pivot shaft 410. A spring
420 biases positioning unit interface plate 402 and support plate 406 in a
counterclockwise direction.
FIG. 9(A) shows rotating member engaging member 394 in a rotating member
disengaging position, wherein drive members 290 rotate with crank arm 266
without causing any effect on assist mechanism 14. In general, when
actuating component 118 of shift control unit 84 is rotated to either the
upshift position or the downshift position, then positioning unit
interface plate 402 and support plate 406 pivot counterclockwise as shown
in FIG. 9(B). This causes rotating member engaging member 394 to pivot
clockwise around pivot shaft 410, since cam follower 414 is retained
within cam slot 386, to the rotating member engaging position shown in
FIG. 9(B). In this position, rotating member engaging surface 398 is
disposed in the path of drive members 290, so one of the drive members 290
will contact rotating member engaging surface 398 as shown in FIG. 9(B)
and cause rotating member engaging member 394 to rotate positioning unit
interface plate 402 and support plate 406 clockwise against the biasing
force of spring 420 as shown in FIG. 9(C). As crank arm 266 continues to
rotate, the engaged drive member 290 will disengage from rotating member
engaging member 394, rotating member engaging member 394 will pivot
counterclockwise as shown in FIG. 9(D) back to the rotating member
disengaging position, and spring 420 will cause positioning unit interface
plate 402 and support plate 406 to pivot counterclockwise back to the
position shown in FIG. 9(A).
FIG. 10 is an enlarged rear cross sectional view of the internal components
of positioning unit 254. As shown in FIG. 10, positioning unit 254
includes a base plate 450 supporting one end of a pawl shaft 470; an
output transmission member in the form of a rotating member 454 rotatably
supported on axle 318 and having a wire winding groove 455 for winding and
unwinding output control wire 78 to a plurality of output positions; a
biasing component in the form of a spring 456 for biasing rotating member
454 in a wire unwinding direction; a positioning member in the form of a
positioning ratchet 458 coupled for integral rotation with rotating member
454; a middle plate 466 supporting the other end of pawl shaft 470; a
position maintaining member in the form of a positioning pawl 474
supported by pawl shaft 470 for rotation between a position maintaining
position and a position release position and having positioning teeth 475
and 476 (FIG. 15(A)); a pivot shaft 477 mounted to positioning tooth 475;
a cam follower in the form of a cam roller 478 rotatably supported by
pivot shaft 477; and a pawl spring 482 connected between positioning pawl
474 and base plate 450 for biasing positioning pawl 474 toward the
position maintaining position (counterclockwise in FIG. 15(A)).
Positioning unit 254 further includes a release plate 486 rotatably
supported on axle 318 and having a pivot shaft 490 supporting a cam member
in the form of a cam plate 494; a motion transmitting member 498 rotatably
supported on axle 318; a pawl shaft 502 mounted to motion transmitting
member 498; a motion transmitting pawl 506 pivotably supported on pawl
shaft 502; a spring 509 for biasing motion transmitting pawl 506 in the
counterclockwise direction in FIG. 15(A); another pawl shaft 510 mounted
to motion transmitting member 498; a mode change pawl 514 pivotably
supported on pawl shaft 510; an input transmission member in the form of a
control plate 518 rotatably supported on axle 318; a base plate 522; a
pawl shaft 526 mounted to base plate 522 and supporting a switch-off drive
control member in the form of a drive control pawl 530; a spring 531 for
biasing drive control pawl 530 in the counterclockwise direction in FIG.
15(A); a pawl shaft 534 (FIG. 15(A)) mounted to base plate 522 and
supporting a switch-on drive control member in the form of a drive control
pawl 538; a spring 539 for biasing drive control pawl 538 in the
counterclockwise direction in FIG. 15(A); a spring retainer 541; a spring
499 connected between spring retainer 541 and motion transmitting member
498 for biasing motion transmitting member 498 in the clockwise direction
in FIG. 15(A), and a retaining nut 542 for axially retaining the
components on axle 318. Base plate 450, base plate 522 and axle 318
function as mounting units for the various components.
FIG. 11 is a side view of motion transmitting member 498. Motion
transmitting member 498 includes a base portion 550, a pawl mounting ear
554 and a motion transmitting arm 558. Base portion 550 includes an
opening 562 for receiving axle 318 therethrough, a radially outwardly
extending projection 566 forming an abutment 570 for contacting drive
control pawl 530, and a radially outwardly extending projection 574
forming an abutment 578 for contacting drive control pawl 538. Pawl
mounting ear 554 includes an opening 582 for mounting pawl shaft 510
(which supports mode change pawl 514), and motion transmitting arm 558
likewise includes an opening 586 for mounting pawl shaft 502 (which
supports motion transmitting pawl 506). Motion transmitting arm 558 also
includes an abutment 588 for contacting drive control pawl 538, and an
axially extending rotating member engaging unit interface plate 590 that
attaches to positioning unit interface plate 402 through screws 594 as
shown in FIGS. 8 and 10.
FIG. 12 is a side view of a particular embodiment of control plate 518.
Control plate 518 includes an input control member in the form of a base
portion 598, a lever arm portion 602, and an input unit interface plate
604. Input unit interface plate 604 includes an opening 605 for receiving
coupling portion 362 (FIG. 6) of input link 306. Base portion 598 includes
input control members in the form of radially extending drive control cam
surfaces or lobes 606, 610, 614 and 618. Drive control cam lobe 606
includes an upper surface 606a and inclined ramps 606b and 606c.
Similarly, cam lobe 610 includes an upper surface 610a and inclined ramps
610b and 610c. Cam lobe 614 includes an upper surface 614a, an inclined
ramp 614b and a transition surface 614c extending from upper surface 614a
to an upper surface 618a of cam lobe 618. Cam lobe 618 further includes a
transition surface 618b extending from upper surface 618a to the outer
peripheral surface 598a of base portion 598. It will become apparent from
the description below that cam lobes 606, 610 and 614, drive control pawl
538 and motion transmitting member 498 with projection 578 comprise a
switching mechanism to control the movement of rotating member engaging
member 394 between the rotating member engaging position and the rotating
member disengaging position.
FIG. 13 is a side view of a particular embodiment of middle plate 466.
Middle plate 466 includes a base portion 630, a pawl coupling arm 634, a
downshift control plate 638, and a pawl coupling portion 642 extending
from downshift control plate 638. Pawl coupling arm 634 includes an
opening 646 for receiving a fastener (not shown) used to attach the
assembly to the housing, and pawl coupling portion 642 includes an opening
650 for attaching pawl shaft 470 (which supports positioning pawl 474).
Downshift control plate 638 defines a recess 656 having a pawl control
surface 660 that functions in a manner described below.
FIG. 14 is a side view of positioning ratchet 458. Positioning ratchet 458
comprises a generally annular body 670 having an inner peripheral surface
672 forming a plurality of female splines 674 that nonrotatably engage a
corresponding plurality of male splines (not shown) formed on rotating
member 454 so that positioning ratchet 458 and rotating member 454 rotate
as a unit. An outer peripheral surface 678 forms three positioning teeth
682, 686 and 690 and two drive teeth 694 and 698 defining drive surfaces
694a and 698a, respectively. With this structure, rotating member 454 can
be set in three positions to accommodate three front sprockets 62. Such
sprockets usually comprise a small diameter sprocket, an intermediate
diameter sprocket, and a large diameter sprocket.
FIG. 15 is a perspective view of motion transmitting pawl 506. Motion
transmitting pawl 506 includes a base portion 506a with an opening 506b
for receiving pawl shaft 502, a downshift control surface 506c for
contacting pawl control surface 660 of middle plate 466 in a manner
described below, a positioning ratchet drive surface 506d, a release plate
drive surface 506e, and mode change pawl contact surfaces 506f and 506g.
FIGS. 16(A)-(E) are views illustrating the operation of positioning unit
254 in an upshifting direction. In FIG. 16(A), positioning unit 254 is in
a position such that front derailleur 70 is aligned with the small
diameter front sprocket, and it is desired to move front derailleur 70 to
the intermediate diameter front sprocket. In the position shown in FIG.
16(A), the tip of drive control pawl 530 is supported by the upper surface
606a of cam lobe 606, and the tip of drive control pawl 538 is located at
the bottom of ramp 610c of cam lobe 610 such that drive control pawl 538
contacts abutment 578 on motion transmitting member 498 and holds motion
transmitting member 498 in a "switch off" position. Thus, drive control
pawl 538 and cam lobe 610 comprise a drive control mechanism that
ordinarily maintains motion transmitting member 498 in the switch off
position. Motion transmitting pawl 506 rests on the upper surface of drive
tooth 694 on positioning ratchet 458.
The rider then rotates actuating component 118 counterclockwise (in FIG. 3)
to the upshift position so that inner wire 80 is released by actuating
component 118. This causes wire coupling member 302 to rotate clockwise in
FIG. 6, and this motion is communicated via input link 306 to control
plate 518 to rotate control plate 518 clockwise to the upshift position
shown in FIG. 16(B). Clockwise rotation of control plate 518 causes drive
control pawl 530 to slide down ramp 606c of cam lobe 606 and rotate
counterclockwise to the position shown in FIG. 16(B). At the same time,
drive control pawl 538 slides up ramp 614b of cam lobe 614 until drive
control pawl 538 disengages from abutment 578 on motion transmitting
member 498 and rests on upper surface 614a of cam lobe 614. Since drive
control pawl 538 no longer contacts abutment 578, motion transmitting
member 498 rotates clockwise until drive control pawl 538 contacts
abutment 588, and motion transmitting member 498 is in a "switch on"
position as shown in FIG. 16(B). Motion transmitting pawl 506, no longer
being held by drive tooth 694 on positioning ratchet 458, rotates
counterclockwise a
