Note: Descriptions are shown in the official language in which they were submitted.
~2~7~03
Patentansokan 8701526-9
Coupling means for a bicycle
This invention relates to a coupling means for a bicycle provided
with a pedal operated brake activating means separated from the drive
chain, and which comprises a first freewheel coupling associated with
pedal crank for torque transmission to the brake activating means at
reverse rotation of the pedal crank and a second freewheel coupling
associated with the drive wheel of the bicycle for torque transmission
to the drive wheel at forward rotation of the pedal crank.
One problem inherent with previously known bicycle designs of this typeresides in the fact that the freewheel coupling in the pedal crank
assembly and the drive wheel hub have had such an engagement direction
that by rearward movement of the bicycle, i e when the drive wheel is
rotated in its reverse direction, such a rearward movement is trans-
ferred by the chain to the pedal crank and further to the brake acti-
vating means, whereby the brake is activated and the bicycle is locked
dead.
This invention intends to accomplish a device which automatically will
inactivate the braking function at reverse rotation of the drive wheel.
Embodiments of the invention are herein below described in detail underreference to the accompanying drawings.
On the drawings:
Fig 1 shows a side elevation of the bicycle comprising the pedal crank
assembly, the drive wheel and the brake device.
Fig 2 shows cross-section along line A-A in Fig 1 including a dis-
engagement means according to the invention.
Fig 3 shows, partly in section, a view of the pedal crank assembly of
the bicycle.
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Fig 4 shows a section along line D-D in Fig 3 and illustrates the
brake activating means as well as the disengagement means.
Fig 5 shows a disengagement device according to the invention lo-
cated in the hub of the drive wheel.
Fig 6 shows a section along line A-A in Fig 5.
Fig 7 shows a section along line B-8 in Fig 5.
Fig 8 shows a longitudinal section through the hub of the drive
wheel according to an alternative embodiment of the invention.
Fig 9 shows a section along line E-E in Fig 8.
Fig 10 shows a section along line F-F in Fig 8.
Fig 11 shows a longitudinal section through the drive wheel hub
according to another embodiment of the invention.
Fig 12 shows a section along line G-G in Fig 11.
The bicycle which is illustrated in Fig i comprises a pedal crank
assembly in which is journalled a pedal crank shaft 2 provided with
rigidly attached pedal arms and a sprocket wheel by which a chain is
connected to the drive wheel of the bicycle. The pedal crank assembly
also comprises a brake activating means which by means of a wire 50
is connected to a rim brake 51.
The brake activating means at the pedal crank assembly comprises a
sleeve 1 which is rigidly attached to the crank shaft 2, a rotating
ring 3 surrounding the sleeve 1 and being drivingly connected to the
latter via friction surfaces 10. See Fig 3. These friction surfaces
10 are conical and are pressed together by means of a washer spring 9
which acts against one of the pedal arms 5. The rotating ring 3 is
provided with ratchet teeth 4 for cooperation with a number of catches
7. The latters are pivotally supported on a ring 6 which in turn is
formed with a radially extending activating arm 8. See Fig 4.
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At forward rotation of the pedal shaft, the catches 7 remain unengaged
in that they are pivoted away from the teeth 4 of the rotating ring 3.
At reverse rotation of the pedal cranks, the catches 7 will engage
positively the teeth 4 and thereby make the ring 6 rotate in a reverse
direction and exert an activating movement on the arm 8. The arm 8 is
coupled to the rim brake 51 by the wire 50. At too a high brake acti-
vating force applied on the pedal cranks, a slipping movement will
occur between the friction surfaces 10 so as to protect the device
against overloads.
ûn the outer peripheri of the ring 6, there is journalled a disengage-
ment ring 11 which by means of a wire 14 is connected to an activating
device on the drive wheel. The ring 11 is formed with grooves 12 which
is located just outside the catches 7 as the ring 11 occupies its in-
active position. As the disengagement device is activated, the ring 11
will be rotated by the wire 14 such that one of the edges 13 of the
grooves 12 will engage and pivot the catches 7 and, thereby, inactivate
the brake activating coupling. This occurs at reverse rotation of the
drive wheel and prevents the braking device, i e the rim brake 51, to
be activated and lock the bicycle dead.
In order to accomplish the above described disengagement of the brake
activating means, the hub of the drive wheel is provided with an ex-
ternal frsewheel coupling in the form of catches 21 arranged between
a ring 20 mounted on the hub and an activating ring 23. See Fig 1 and
2. The activating ring 23 is coupled to a wire activating arm 28 by
means of a friction coupling 25, 26. At reverse rotation of the d~ive
wheel, the catches 21 will establish a rigid connection between the
ring 20 and the activating ring 23 and, thereby, move the activating
arm 28 backwards, and through the wire 14 rotate ring 11 and disengage
the catches 7 in the pedal crank assembly. For enabling a longer re-
verse movement of the drive wheel, the friction coupling 25, 26 will
allow the activating arm 28 to slip relative to the activating ring 23.
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According to the above described embodiment of the invention, the bi-
cycle comprises a freewheel coupling associated with the drive wheel
and which by means of an activating means is intended to inactivate
the brake activating device in the pedal crank assembly. In Fig 5, 6
and 7, there is shown an embodiment of the invention in which the dis-
engagement device is located within the hub of the drive wheel and
arranged to inactivate the freewheel coupling of the drive wheel by
which the drive force is transmitted from the chain sprocket to the
drive wheel. In the embodiment of the hub shown in Fig 5, the dis-
engagement device is located at the hub of the drive wheel and com-
prises a non-rotating shaft 29 locked to the frame of the bicycle.
In the drive wheel, there is immovably connected a hub sleeve 42
which on its outside supports a drive sleeve 44 journalled on ball
bearings. On the drive sleeve 44, there are rigidly mounted a number
of chain sprockets 40 of different sizes. The drive sleeve 44, which
is rotatably journalled on the hub sleeve 42, is arranged to transfer
the drive force from the chain and the chain sprockets 40 to the wheel
via a number of catches 43, which form a freewheel coupling between
the drive sleeve 44 and the hub sleeve 42.
In order to accGmplish a discontinuation in the connection between the
wheel and the brake activating means in the pedal crank assembly and,
thereby, avoid a locking dead of the bicycle at reverse movement, this
embodiment of the invention comprises means in the drive wheel hub for
deactivating the catches 43. For that purpose, a deactivating sleeve
30 is journalled in the hub sleeve 42. The,activating sleeve 30 is
arranged to move the catches 43 to an inactive position at rearward
movement of the wheel. This is accomplished by means of catches 32
and a tooth ring 33 journalled on a non-rotating sleeve 34.
The catches 32 and the tooth ring 33 form a third freewheel coupling
which has the same direction of engagement as the freewheel coupling
in the pedal crank assembly as well as the freewheel coupling between
the drive sleeve 44 and the hub sleeve 42. The tooth ring 33 is
coupled to the non-rotating sleeve 34 by means of a friction coupling
33, 36 for enabling slippage of the tooth ring 33 at extended rear-
ward movement o~ the wheel. As being illustrated in Fig 6, the dis-
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engagement sleeve 30 is formed with openings 30a into which the catch43 extends at normal operation of the bicycle. At reverse rotation
and locking of the deactivating sleeve 30 by means of the catches 32,
the sleeve 30 will force the catch 43 out of the opening 30a, and
thereby, move the catch 43 out oF engagement with the drive sleeve
44. The openings 30a have a larger circumferential extent than the
catch 43 and enables a rotational play between the sleeve 30 and the
catch 43. This play is intended to give a delay of the disengagement
of the catch 43. Return movement of the sleeve 30 is ensured by a
torsion spring 31.
For preventing any kind of load from acting on the catch 43 and make
disengagement of the latter more difficult when acted upon by the
sleeve 30, the drive sleeve 44 is provided with a coupling ring 39
which is rotationally locked relative to the latter except for a
play 46. See Fig 7. To ensure that this play will always offer a
certain degree of free running of the ring 39 at the start of the
reverse movement of the wheel, there is incorporated a spring 47
which is active to turn the sleeve 39 in that direction in which the
play to the drive sleeve 44 is ensured. This rotational play between
the ring 39 and the drive sleeve 44 also intends to avoid locking
dead of the bicycle at heavy braking. Due to the elasticity of the
brake force transmitting means, a rotational play is required to avoid
the drive catch 43 to engage before the brake has been released.
In the above described embodiments of the invention, there are de-
scribed two alternative locations of a third freewheel coupling in
order to accomplish a deactivation of anyone of the other freewheel
couplings, i e either the freewheel coupling in the pedal crank as-
sembly or the freewheel coupling in the drive wheel hub, and in which
deactivating means are incorporated to avoid locking dead of the bi-
cycle at a longer reverse movement of the bicycle.
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In Fig 8, 9 and 10, there is shown an alternative embodiment of the
invention in which a deactivating means is incorporated in the hub
of the drive wheel for deactivating the freewheel coupliny of the
drive wheel by which the drive torque is transferred from the chain
sprocket to the wheel. In the embodiment shown in Fig 8~ the de-
activating means comprises a non-rotating shaft 60 rigidly locked
to the bicycle frame. A hub sleeve 61 is rigidly attached to the
drive wheel and is journalled by means of a ball bearing on a drive
sleeve 63. The latter is in turn journalled on the shaft 60 by means
of two ball bearings and carries a number of chain sprockets 62 of
different sizes. The drive sleeve 63 is arranged to transfer a power
from the chain and the chain sprockets 62 to the wheel via a number
of catches 64 which form a freewheel coupling between the drive sleeve
63 and the hub sleeve 61.
In order to accomplish a discontinuation in the connection between
the drive wheel and the brake activating means in the pedal crank
assembly and to avoid locking dead of the bicycle at reverse move-
ment, this embodiment of the invention comprises means in the drive
wheel hub for deactivating the catches 64. For this purpose, there is
journalled a toothed deactivating sleeve 65 in the hub sleeve 61, such
that deactivating sleeve 65 via catches 66 and a catch supporting
ring 67 is arranged to move the catches 64 to their rest positions
at reverse rotation of the wheel. The catches 66 and the toothed de-
activating sleeve 65 form a third freewheel coupling. The catch sup-
porting ring 67 is journalled on a non-rotating sleeve 71 by means of
a friction coupling to enable slippage at long reverse movements.
The friction coupling comprises the catch supporting ring 67, a ring
69 firmly attached to the shaft 60 and a spring 72 for pressing to-
gether the catch supporting ring 67 and thè ring 69. The spring 72
is axially supported by a sleeve 68. As being apparent from Fig 9,
the deactivating sleeve 65 is formed with a sloping surface 65a which
leaves the catch 64 unaffected at normal operation of the bicycle.
The deactivating sleeve 65 is kept in its inactive position by means
of a pretensioned spring 75. At reverse movement and interengagement
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between the deactivating sleeve 65 and the catches 66, the deacti-
vating sleeve 65 will force the catch 64 up on the sloping surface
65a, and thereby, move the catch 64 out of engagement with the drive
sleeve 63.
For preventing any kind of load from acting on the catches 64 and
make deactivation of the latter more difficult when acted upon by
the deactivating sleeve 65, the drive sleeve is provided with a
coupling ring 70 which is drivingly coupled to the drive sleeve 63
over a play 73. See Fig 10. To make sure that this play will always
enable a certain degree of freerunning of the coupling ring 70 at the
start of the reverse movement of the wheel, there is provided a spring
76 which is active to turn the coupling ring 70 in the direction in
which the play relative to the drive sleeve 63 is ensured. This
rotational play between the ring 70 and the drive sleeve 63 also
serves as an insurance against locking dead of the bicycle at heavy
braking. Due to the elasticity in the brake force transmitting means,
a rotational play is required to avoid the catches 64 to get engaged
before the brake has been released.
In Fig 11 and 12, there is shown still another embodiment of the
invention in which the deactivating means is located inside the
sprocket wheel unit of the drive wheel and arranged to deactivate
the freewheel coupling by which the propulsion force of the bicycle
is transmitted from the sprocket wheels to the drive wheel. According
to this embodiment of the invention, the device comprises a non-rotatable
shaft 129 rigidly attached to the frame of the bicycle. To the drive
wheel, there is rigidly attached a sleeve 14Z which on its outside
carries a drive sleeve 144 journalled on a ball bearing. On the
drive sleeve 144, there are non-rotatably mounted a number of chain
sprockets 140. The drive sleeve 144 which is rotatably journalled
on the hub sleeve 142 is intended to transmit the propulsion force
from the chain sprockets 140 to the wheel by means of a number of
catches 143 which form a freewheel coupling between the drive sleeve
144 and the hub sleeve 142. In order to accomplish a discontinuation
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of the connection between the drive wheel and the brake activating
means in the crank assembly to thereby prevent locking dead of the
bicycle at reverse movement, there is rotatably mounted a deactiv-
ating sleeve 13û within the hub sleeve 142. By means of catches 132
and a toothed ring 133 mounted on the deactivating sleeve 130, the
latter is intended to move the catches 143 to their inactive posi-
tions at reverse rotation of the wheel. The catches 132 and the
toothed ring 133 form a third freewheel coupling. The deactivating
sleeve 130 which is formed with a sloping surface is coupled to a
ring 150 with a corresponding sloping surface for accomplishing of
an axial movement of the deactivating sleeve 130. The ring 150 is
rotated by means of a friction coupling 135, 136 which allows the
ring 150 to slip at longer reverse movement.
As been illustrated in Fig 12, the deactivating sleeve 130 comprises
a conical portion 130a which does not influence upon the catch 143
at normal operation of the bicycle, but is kept in inactive posi-
tion by a pretensioned spring 131. At reverse rotation and activa-
tion of the deactivating sleeve 130 via the catches 132, the deacti-
vating sleeve 130 will rotate and, at the same time, be axially
displaced by engagement of the sloped surfaces against the corre-
sponding surfaces on ring 150. Thereby, the drive catches 143 are
moved out of engagement with the drive-sleeve 144.
In the drive wheel hub shown in Fig 11, there is comprised a fourth
freewheel coupling, the purpose of which is to activate the coupling
sleeve 130 during braking so as to prevent locking dead of the bicycle
at braking to stillstand. This freewheel coupling comprises a sleeve
148 in which is journalled a coupling ring 139 which carries catches
155. The sleeve 148 is formed with grooves 146 which enables a~rota-
tional play of the coupling ring 139. A spring 147 acts to maintain
this play at normal operation of the bicycle.
