Note: Descriptions are shown in the official language in which they were submitted.
WO 91/1g638 PCr/CA91/00196
208~
AUTOMATIC DE~:RAILLEUR SHIFTER
This invention relates to an automatic derailleur
shifter system for a vehicle which is a bicycle which includes
a pedal powered chain wheel which drives through a chain one of
a set of driven sprockets attached to a drive wheel of the
vehicle.
Most bicycle gear systems now use a derailleur
system which includes an idler gear mounted upon a spring
system which tensions the chain and acts to move the chain to a
selected one of a set of driven spcockets. The derailleur
system has become over the years very finely tuned and now
generally includes also a locator arcangement which ensures
that the changing mechanism is properly positioned at one of
the driven sprockets of the set in preference to intermediate
positions. In addition the gear chain system often includes
two or even three chain wheels at the drive end which are
attached to the pedal arrangement together with a changer
system which moves the chain across between the drive
sprockets. Some systems have now reached the complexity of
having twenty one pos ible change c~mbinations provided by
three drive sprockets at the forward end and seven driven
sprockts at the rear hub. The systems are changed by a simple
lever arrangement which pulls upon a cable to move the front
SUBS~I~UTE S~ ET
.
~ .
.
.
WO91/19638 PCTJCA91/00196
~ ~ - 2 -
chain system or the derailleur system at the option of the
rider. The cidec is therefoce faced with a wide variety of
possibilities and only the most experienced and enthusiastic of
ciders can control the geac system sufficiently to màintain the
pedal pressure or torque within the celatively narrow cange
which is preferred.
Attempts have been made ovec many yea~s to
- - provide an automatic change system which detects the amount of
torque or presqure applied to the pedals and then changes the
gear catio automatically to attempt to maintain the tocque
wit~in relatively narrow band.
Various arrangements are shown in U.S. Patents
3,929,025 (Prry); 4,599,079 (Chappell); 3,831,978 (Dunder);
4,781,663 tReswick); 4,061,046 tLang); 4,343,613 tLeiter) and
3,769,848 (McGuire).
Most of these arcangements provide highly complex
detection systems including additional elements mounted on the
bicycle for detecting the tension in the chain or additional
elements for detecting the pressure at the pedals.
The McGuire paten~ provides a relatively simple
device in which the sprocket set is caused to move axially of
the rear axle by a screw thcead coupling on an innec surface of
the sprocket set and outer surface of the axle~ On the face of
SUBSTITUTE SHEET
, ~ . . . ~ .
.
~ ~ . . . - . .
;. . . - : :
,
WO91/19638 PCT/CA91/00196
2 ~ ~. .r., ~
it this arcangement is relatively simple but it cequires a
signiicant modification of the structure of the bicycle so
that the sproc~et set is ac~anged on the outside of the forks
rather than on the inside as is the conventional arcangement.
The device cannot these~oce be ~imply attached to an existing
bicycle and major modifications to the bicycle or a special
bicycle are necessary.
- In any event none of the devices proposed has had
any significant impact on the marketplace and basically no
automatic shifting acrangement is curcently available.
Figure l is a side elevational view of a portion
of a bicycle showing the dcive system.
Figure 2 is a cros~-sectional view through the
hub of the reac wheel of the bicycle of Figure l.
Figure 3 ia a cross-sectional view along the
lines 3-3 of Figuce 2.
Figure 4 is an exploded view of the parts of the
hub of Figuce 2.
Figure 5 is a side elevational view of the
opposed side of the bicycle showing only the area adjacent the
reac hub and on an enlarged scale.
The bicycle of Figure l comprises a reac wheel lO
including a hub generally indicated at ll. The hub is mounted
SUBST~TlJ~lE S3HEET
W091/19638 PCT/CAgl/00196
~ - 4 -
in r~ar forks 12 including an upwacdly inclined portion 13 and
a downwardly inclined portion 14 of a conventional frame
arrangement. The hub is clamped in a C-shaped bcacket lS at
the apex between the por~ions 13 and 14.
A ~cont chain wheel foc driving the reac wheel is
indicated at 16 and is connected to a conventional pedal system
indicated at 17. The chain wheel system includes a plurality
of sprockets 18 and 19 which ace acranged coaxially around the
axis of the pedals 17 and axially spaced in conventional
mannec. A chain 20 cooperates with the chain wheel system and
is movable by a conventional gear changing system indicated at
21 which can transec the chain from the largest chain wheel as
shown to one o~ more of the smaller chain wheels (only pastly
visible).
The hub carries a sproc~et set 22 again of
conventional con~truction with the sprockets of the set
acranged coaxia~ly and axially spaced 90 that the chain can
move from one to the next undec actuation by a decailleur
system schematically indicated at 23.
The p~rts illustrated in Figure 1 ace generally
of conventional nature and are modified by the device as
desccibed heceinaftec particularly in celation to Figuce 2.
The hub genecally indicated at 11 includes an
SUB5~ITU ~ ~ SHEET
.
: :
.
WO91/196~ PCT/CA91/00196
21~ 6~i
outec hub poetion 24 in the form of a sleeve having a hollow
interior 25. On an outer surface of the hub is provided a pair
of axially spaced annular flanges 26 and 27 which include holes
28 as best shown in Figure 3 foc connection to spokes which
suppoct the outec cim of the wheel 10.
The inner surace defining the hollow intecior
includes a lacgec portion 29 adjacent the left hand end of ~he
outer hub portion and a larger countecboard poction 30 towacd ~
the right hand end of the hub portion. A single boce 31
extends axially of the hub portion at a position outside the
smaller poction 30. The smallec portion 30 includes a paic of
keyways 32 and 33 extending axially of the hub poction at 180
spacing as best shown in Figure 3.
Inside the smaller portion 30 is mounted a sleeve
membec 34 having lengths substantially equal to the length of
the smallec portion 30. The sleeve 34 has on its outer surface
a pair of ribs extending axially and arranged foc cooperation
with the keyways 32 and 33, the ribs being indicated at 35.
This allows the sleeve to ~ove axially relative to the hub
poction but it is constrained to rotate with the hub portion by
the cooperation with the ribs and the keyways. An inner
surface of the sleeve 34 includes a female screw thcead 36
defined by celatively wide bands of rectangular shape.
S~BS~ T~ SI~EET
WO91/19638 PCT/CA91/00196
~? ~ 6 -
Inside the sleeve is mounted an axially extending
sxtension poetion 37 of the sprocket set suppoct member 38.
The sprocket set suppoct member includes an annular support
surface 39 on which the sprocket set (not shown) is mounted
together with a free wheel arrangement which allows the
sprocket set to drive forward motion of the support ~ember bu~
to freewheel in the reverse direction. ~ocwardly of the
suppoet surface 39 is a flange member 40 -which carries on a
inwardly facing surace 41 theeeof, a bearing support portion
42 for receiving balls 43 of a bearing element cooperating
between an outer surface of the hub portion as indicated at 44
and the inner sucface of the support member 38. The bearings
43 thus allow limited rotation be~ween the support member 38
and the hub portion 24. This movement is to some extent
controlled by a ball 45 biased forwardly of the boce 31 by a
spring 46 which cooperates with a plurality of indentations on '!
the inner surface of the flange 40. Thu-~ the support member is
constrained to rotate through a limited amount relative to the
hub portion through disccete steps defined by the location of
the ball 45 within the recesses.
The axially extended portion 37 includes an outer
male screw thread 47 shaped to cooperate with the f~male screw
thread on the sleeve 34. The screw thrsad has a relatively
SIJ~S ~ ~TU~ SHEET
W091/19638 PCT/CA91/00196
2~g~ 6~
large helix angle so that rotation of the support member 38
relative to the hub portion through an angle less than 180
causes movement of the sleeve 34 in an axial direction to its
fullest extent.
Inside the support member 34 is provided the axle
48 including a hollow continuous boce 49 along the length
thereof. The outer surface of the axle 48 includes a screw
threaded sec~ion 50 at each end for cooperation with a nut 51.
Inside the screw threaded portion 50 is a first cylindcical
poction 52 followed by a second cylindrical poction 53 and
followed by a square portion 54. A slot 55 is found in the
squace portion and extends through the square portion to
cooperate with the channel 49.
A cone member 56 ~ucrounds the poction 52 of the
axle and defines a bearing receiving sec~ion 57 which pre~ses
kearing assembly 58 against a surface 59 of the support member
38. Thus the main bearings defined by the bearing 58 allow the
support member to rotate freely relative to the cone and thus
celative to the axle to which the cone is clamped by the lock
nut 51. In conventional mannec the bracket portion of the
focks of the frame of the bicycle is clamped between the loc~ -
nut 51 and an outec wheel nut (no~ shown).
In ide the lacger portion of the hollow intecior
:`
SUBSTi~ Si~ E ET
WO 91/19638 PCr/CA91/00196
.
. ~. .~j,,.i
-- 8 --
of the hub portion is provided a sleeve member 60 which is free
~o rotate relative to the hub portion on bearing 61 defined
between su~faces 62 and 63 of the sleeve member and the hub
portion reapec~ively. The bearing 61 again defines the main
bearing foc cotation of the hub celative to the axle. The
sleeve member 60 is free to cotate celative to the axle on
subsidiary bearings 64 defined between an end surface of the
sleeve member indicated at 65 and a~ cone membec 66 clamped to
the axle by a nut 67 applied on the threaded portion 50. The
sleeve member 60 has a female screw thcead 68 on the internal
sucface thereof which cooperates with a male screw thcead on
the outer surface 69 of a second membec 70. The second member
as best shown in ~igure 4 cooperates with a square portion 54
of the axle so that it can move axially along the axle but is
pcevented from cotation of the axle by the square section and
also by a transverse pin 72 which passes into the slot 5~ and
engages a cable 73 extending along the hollow channel 49 of the
axle. The cable 73 is thus moved axially along the channel as
the second member 70 is ~orced axially. The cable includes a
cable casing 73A inserted into the axle and stabilized by an
indent 73B. The cable further includes a cable head 73D
ceceived within an indent 73C in the pin 72. A replacement
cable can be threaded axially sf the axle from the left hand
SU~ E ~I IEET
WO 91t14638 PCTICA91/00196
2V~f~j
g
end.
An end face of the qecond member 70 ca~ries a
thrust bearing 75 which engages an end face of the sleeve 34.
The sleeve 34 rotates with the hub whereas the second member 70
is held stationacy relative to the axle and thus the th~ust
bearing takes up the cotation and communicates focce between
the second member 70 and the sleeve 34. Axial movement of the
- - -sleeve 34 thus forces the second membec 70 axially. The
... . . . , _ , . _ . . _ . _ . .
cooperation between the outside screw thread 69 and the inside
screw thread 68 on the sleeve member 60 cau~es the sleeve
member to rotate in a clockwi e direction a-~ best hown in
Figure 5. In this figure an annular end flange portion 60A of
the sleeve 60 is exposed at the end of the hub opposite to the
sprocket set and this acts as a control member for the
automatic changing system.
In particular the flange 60A is attached to a
nipple 76 carried on the end of a wire 77 attached to a spring
78. The spcing 78 i~ mounted within a sleeve 79 connected onto
the upw~rdly inclined ~ork portion 13 by a bracket 80. The
tension on the spring can be adjusted by a nut 81 which causes
the sleeve 79 to be moYed longitudinally of the wire 77. The
spring 78 thus provides a resi~ting force to the cotation of
the flange 60A and thus to the axial movement of the second
SUE~STITUTE SHEET
,
WO91/19638 PCT/CA91/00196
-- 10 --
membec 70.
In operation of this portion of the device, the
torque applied to the spcocket set by the chain causes a
movement of the support member in a drive direction relative to
the hub thus forcing the sleeve 34 in an axial direction toward
the left as shown in Figure 2. This movement is resisted by
the spring 78 so that a balance is obtained in which the amount
of torque applied is maintained within limits controlled by the
spcing. As the tocque tends to increase, the sleeve 34 moves
to the left and this acts to move the wire cable 73 to the left
thus pulling the cable 73 to actuate the gear change mechanism
of the decailleur 23. Automatically thecefoce the geac chan~e
is actuated towacd a lower gear as the torque increases.
The amount of ~orque necassary to change gear can
be vacied by adjusting the effect of the spcing 78 in
accordance with the weight of the cider.
The front change mechanism 21 of the chain wheel
set 16 is actuated by a cable 83 shown in Figure 5. The cable
is contcolled by a V-shaped camtrack 84 defined in a plate 85
carried by the annulac flange 60A. The plate is attached to
the flange 60A by rivets 86 ~o as to stand outwardly to one
side and lying in a plane of the front face of the flange 60A.
The v-shaped camtrack 84 has a bottom end 87, a base of the
SUBSTIFU ~ E SHET
-- .
- , . ~ . - . .
WO91/19638 PCT/CA91/00196
2 0 ~ ~ r~ ~ t?
V-shape indicated at 88 at an opposed end 89. The device is
constrained by the ratio of the helix angle of the screw
threads so that the plate moves through an angle of the order
of 90. A- the plate thus moves in a cloc~wise dicection
through 45 , a cigid wice connector 9O mounted at the end of
the wire 83 and including a right angle arm 90B and head 90A
slides along the cam track 84 to the base position 88 allowing
- the spring action (not shown) at the front change mechanism 21
to cause the chain mechanism to allow the chain to move into
position on an intermediate one of the three chain wheels at
the chain wheel set. The head 90A of the wire connector run-c
against a rear face of the cam plate 85. The extended state of
the front deeailleur is arranged such that it positions the
chain on the largest spcocket for high gsar opecation.
Furthermore as the plate a5 is moved from the 45 position to
the 90 position, the nipple 9O moves to the outec end 89 of
the V-shaped camtrack which at this time has moved in the
clockwise direction so ~hat the cable is furthec released
allowing the spring at the change mechanism to cau~e the chain
to move the smallest of the chain wheels.
The device is thus set up qo that in ope~ation
the change mechanism at the sprocket set causes the change
first~y from the first to the third of the drive sprockets
SVBSTITUl'E SHEET
'
.
WO91/19638 PCT~CA91~00196
'l,.~ C
- 12 -
following which a change occurs at the front chain wheel from
the first to the second chain wheel. The device then causes,
as the torque further increases, a change from the third to the
fifth of the drive sprockets. Subsequently the front change
mechanism cauYes a change from the second to the third of the
chain wheels. ~inally the device is arranged to cause a change
from the ~ifth to the seventh of the drive sprockets.
- - The device there~ore provides an automatic change
system which can act both on the rear ~nd the front change
systems and i~ mounted substantially wholly at or wi~hin the
hub enabling the device to be replaced into a conventional
bicycle using the conventional chain system 21 and a
conventional derailleur sy~tem 23.
SUBST!~U~E SHEET
:. .
