192 clutches and power-stop control – Clutches – Velocipede free wheel
Reexamination Certificate
1999-12-02
2001-06-12
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Velocipede free wheel
C192S094000
Reexamination Certificate
active
06244405
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a free-wheel hub transmission mechanism for a bicycle.
2. Description of the Related Art
Referring to
FIGS. 1 and 2
, a conventional free-wheel hub transmission mechanism
10
according to U.S. Pat. No. 5,718,315 is shown to include an axle
12
, a spoke mounting barrel
11
rotatably mounted on the axle
12
by means of first and second bearing units
14
, a sprocket mounting barrel
13
which is rotatably mounted on the axle
12
by a third bearing unit
14
for driving the spoke mounting barrel
11
and which has a threaded portion
131
extending into the through-hole
111
of the spoke mounting barrel
11
and a sprocket mounting portion
132
extending outwardly of the spoke mounting barrel
11
, and a sprocket (not shown) mounted on the sprocket mounting portion
132
. A hollow reinforcing body
113
is provided in the through-hole
111
around the axle
12
and is coupled to the spoke mounting barrel
11
for simultaneous rotation therewith. A clutch barrel
15
is disposed in the through-hole
111
of the spoke mounting barrel
11
around the axle
12
, and has a coupling portion which engages threadedly the threaded portion
131
of the sprocket mounting barrel
13
and a driving portion
151
which extends into and which drives the reinforcing body
113
. A compression spring
16
is mounted in the through-hole
111
around the axle
12
to bias the clutch barrel
15
against the reinforcing body
113
. A cup
18
is mounted in the through-hole
111
of the spoke mounting barrel
11
around the axle
12
and is secured in place by a respective lock nut
19
to stop the clutch barrel
15
and the compression spring
16
from moving to the right. The clutch barrel
15
is movable along the axle
12
toward the reinforcing body
113
for frictional engagement therewith upon rotation of the sprocket mounting barrel
13
in a first direction, thereby driving the reinforcing body
113
and the spoke mounting barrel
11
to co-rotate with the sprocket mounting barrel
13
. The clutch barrel
15
is disengageable from the reinforcing body
113
upon rotation of the sprocket mounting barrel
13
in a second direction opposite to the first direction.
The reinforcing body
113
has a tapering bore for receiving and engaging frictionally the driving portion
151
of the clutch barrel
15
.
The drawbacks of the aforementioned conventional free-wheel hub transmission mechanism are as follows:
A frictional clamping force (F) will result between the clutch barrel
15
and the reinforcing body
113
when the sprocket mounting barrel
13
rotates in the first direction. The clamping force (F) can be broken into axial and radial components (Fx,Fy), and the radial component (Fy) is usually absorbed during rotation of the assembly. However, the axial component (Fx) will cause an axial outward expelling effect on the reinforcing body
113
and the sprocket mounting barrel
13
relative to the spoke mounting barrel
11
that can affect smooth rotation of the hub transmission mechanism and that will result in a shorter service life.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a free-wheel hub transmission mechanism which includes a clutch barrel that cooperates with a sprocket mounting barrel to clamp a driving transmission block on a spoke mounting barrel such that axial components of the clamping forces cancel each other to ensure smooth operation and a long service life for the hub transmission mechanism.
Accordingly, a free-wheel hub transmission mechanism of the present invention includes an axle with left and right axle portions, a tubular spoke mounting barrel, a drive transmission block, a tubular sprocket mounting barrel, a tubular clutch barrel, and a stop unit, and a friction unit. The spoke mounting barrel has left and right end portions, and a longitudinal through-hole that extends in an axial direction through the left and right end portions. The axle extends co-axially through the longitudinal through-hole such that the right axle portion of the axle is disposed outwardly of the spoke mounting barrel. The spoke mounting barrel is provided with a first bearing unit for mounting rotatably the same on the left axle portion. The drive transmission block is disposed in the right end portion of the spoke mounting barrel, and has a coupling portion that forms a spline connection with the right end portion of the spoke mounting barrel such that the drive transmission block is linearly displaceable in the axial direction and is non-rotatable relative to the spoke mounting barrel. The drive transmission block further has a force transmitting portion that extends from the coupling portion and that projects radially into the through-hole. The force transmitting portion has opposite ends spaced apart from each other in the axial direction, and first and second bevel faces between the opposite ends. The first bevel face is proximate to one of the opposite ends that is adjacent to an open side of the right end portion of the spoke mounting barrel. The second bevel face is proximate to the other one of the opposite ends that is distal to the open side of the right end portion of the spoke mounting barrel. The sprocket mounting barrel is disposed around the right axle portion of the axle, and has an axle mounting portion provided with a second bearing unit for mounting rotatably the same on the right axle portion, and a drive portion that extends from the axle mounting portion in the axial direction toward the right end portion of the spoke mounting barrel and that is formed with a first screw thread. The drive portion is further formed with a third bevel face for contacting the first bevel face. The clutch barrel is disposed around the axle, and has a block contacting part that is disposed inside the right end portion of the spoke mounting barrel, and a coupling part that extends from the block contacting part and that is formed with a second screw thread for coupling threadedly with the first screw thread of the drive portion of the sprocket mounting barrel. The block contacting part is formed with a fourth bevel face for contacting the second bevel face. The clutch barrel is linearly displaceable relative to the axle between a driving position, where the clutch barrel cooperates with the sprocket mounting barrel to clamp the drive transmission block therebetween by virtue of tight contact of the third and fourth bevel faces with the first and second bevel faces such that rotation of the sprocket mounting barrel relative to the axle is transmitted to the spoke mounting barrel via the drive transmission block. The clutch barrel is further linearly displaceable relative to the axle from the driving position to an idling position, where the fourth bevel face ceases to contact the second bevel face tightly to prevent the rotation of the sprocket mounting barrel relative to the axle from being transmitted to the spoke mounting barrel. The stop unit is disposed on the axle for limiting movement of the clutch barrel toward the idling position. The friction unit provides resistance to rotation of the clutch barrel relative to the axle, thereby enabling linear displacement of the clutch barrel relative to the axle to permit movement of the clutch barrel between the driving and idling positions when the sprocket mounting barrel rotates, and permitting the clutch barrel to rotate with the sprocket mounting barrel when the clutch barrel has reached the driving and idling positions.
REFERENCES:
patent: 4593799 (1986-06-01), Ozaki
patent: 4829841 (1989-05-01), Ogawa
patent: 5669477 (1997-09-01), Chen
patent: 5718315 (1998-02-01), Chen
patent: 5964332 (1999-10-01), King
patent: 59-175637 (1984-10-01), None
Bonck Rodney H.
Kun Teng Industry Co., Ltd.
Ohlandt Greeley Ruggiero & Perle L.L.P.
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