Photography – With film drive – Mechanical detail
Reexamination Certificate
1999-10-25
2001-08-21
Perkey, W. B. (Department: 2851)
Photography
With film drive
Mechanical detail
C396S418000, C192S044000
Reexamination Certificate
active
06276845
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a power transmission mechanism such as a clutch device for power transmission.
A one-way clutch device, for example, is used as a clutch device for performing power transmission switching.
The one-way clutch device is characterized in that a rotational force is transmitted only in one direction, i.e. only from a driving-shaft side to a driven-shaft side, but not from the driven-shaft side to the driving-shaft side.
The one-way clutch device is applied to, for example, a film feeder mechanism for use in a camera as disclosed in Japanese Patent Application KOKAI Publication No. 3-200128.
FIG. 12
shows a driving force transmission system incorporated in the film feeder mechanism.
In the film feeder mechanism, the driving force of a driving motor
103
as a driving source is transmitted to a sun gear
106
, incorporated in a planetary gear mechanism, via a pinion
104
and a gear train
105
. A planetary gear
107
incorporated in the planetary gear mechanism is selectively engaged with a driven gear
108
or a driven gear
109
. The driven gear
108
is coupled to a gear
102
a
attached to a spool shaft
102
via a spool-side gear train
111
, and also to an input-side gear
110
a
incorporated in a one-way clutch
110
.
On the other hand, the driven gear
109
is engaged with an output-side gear
110
b
incorporated in the one-way clutch
110
. The output-side gear
110
b
is coupled to a cartridge driving gear
113
via a cartridge-side gear
112
.
The cartridge driving gear
113
has a fork section
113
a
engaged with a cartridge shaft
114
. Concerning the one-way clutch
110
, a direction indicated by arrow D
13
is supposed to be the forward direction of rotation.
When forwarding a film
120
b
y the film feeder mechanism, the driven gear
108
is rotated via the planetary gear mechanism in a direction indicated by arrow D
11
. The cartridge driving gear
113
rotates via the one-way clutch
110
and the gear train
112
to forward the film
120
. At the same time, the spool shaft
102
is also driven via the spool shaft gear train
111
. When winding the forwarded film
120
on the spool shaft
102
, the spool-shaft side forwarding speed is set higher than the cartridge-side speed.
Accordingly, an over-running state occurs in which the cartridge driving shaft
113
rotates at a high speed, and the output-side gear
110
b
is driven in the direction D
13
at a relatively higher speed than the input-side gear
110
a
. The winding operation when photographing is the same as the above driving operation.
When rewinding the film, the motor
103
is rotated in an opposite direction to the above to engage the planetary gear
107
with the driven gear
109
, whereby the driven gear
109
is rotated via the planetary gear mechanism in a direction indicated by arrow D
12
. Then, the output gear
110
b
of the one-way clutch
110
is directly rotated in a direction opposite to the direction D
13
, thereby rewinding the film
120
on the cartridge shaft. At this time, the spool shaft
102
is rotated in a direction opposite to the direction indicated by the arrow, in accordance with the movement of the film
120
.
FIG. 13A
illustrates an example of a structure of the one-way clutch.
In
FIG. 13A
, a driven-side ring
201
is constructed such that it covers a driving-side input shaft
202
with a predetermined space interposed therebetween. In this example, two rollers
200
a
and
200
b
are movably provided in the spaces defined between the driven-side ring
201
and the input shaft
202
. When the driving-side input shaft
202
rotates in a direction indicated by arrow A, the rollers
200
a
and
200
b
each contact both an inner surface
201
a
of the driven-side ring
201
and a flat surface
202
a
of a cam section
202
b
of the driving-side input shaft
202
. As a result, the driving force of the driving-side input shaft
202
is transmitted to the driven-side ring
201
via the rollers
200
a
and
200
b
, which means that both the input shaft
202
and the driven ring
201
rotate in the direction A. After the driving-side input shaft
201
starts to rotate at a higher speed than the ring
202
, the rollers
200
a
and
200
b
are pushed by the inner surfaces
201
a
of the driven-side ring
201
in the direction of the rotation of the ring
201
, thereby releasing the rollers held between the inner surfaces
201
a
and the flat surfaces
202
a
, and hence stopping the transmission of the driving force from the driving-side input shaft
202
to the driven-side ring
201
.
When the rotational speed of the driving-side input shaft
202
has again become relatively higher than the driven-side ring
201
, the two rollers
200
a
and
200
b
are held between the input shaft
202
and the ring
201
to thereby restart the transmission of the driving force from the input shaft
202
to the ring
201
. On the other hand, when the driving-side input shaft
202
rotates in a direction indicated by arrow B, the rollers
200
a
and
200
b
are urged by the flat surfaces
202
c
of the input shaft
202
, which does not cause the rollers
200
a
and
200
b
to be held between the input shaft
202
and the ring
201
. As a result, no driving force is transmitted to the driven-side ring
201
.
FIG. 13B
is a sectional view of the one-way clutch.
As is shown in
FIG. 13B
, the driven-side ring
201
and the driving-side input shaft
202
are held between two bottom boards
203
and
204
such that the rollers
200
a
and
200
b
can move between the ring
201
and the input shaft
202
.
As described above, the film feeder mechanism disclosed in Japanese Patent Application KOKAI Publication No. 3-200128 employs the one-way clutch
110
for linking the spool shaft with the cartridge side. However, the one-way clutch
110
cannot cause two-way transmission of a force supplied from the input driving side, and hence it is necessary to directly drive the output-side gear
110
b
when rewinding the film
120
a
s shown in FIG.
12
.
To directly drive the output-side gear
110
b
, it is necessary to use another driving system for directly driving the gear
110
b
. Further, since the one-way clutch
110
has to be located between the cartridge driving system and the spool driving system, much space is required in the camera, and the structure of the camera is inevitably complicated.
BRIEF SUMMARY OF THE INVENTION
The present invention has been developed in light of the above-described circumstances, and aims at providing a power transmission mechanism which can perform transmission of two opposite directional rotations of a driving shaft to a driven-shaft side, and has a high degree of freedom in arrangement when it is applied to a driving power transmission system.
According to a first aspect of the invention, there is provided a power transmission mechanism comprising: a driving member rotatable both forward and backward; a driven member coaxial with the driving member; a first power transmission member for transmitting a forward driving force of the driving member to the driven member; and a second power transmission member for transmitting a backward driving force of the driving member to the driven member.
According to a second aspect of the invention, there is provided a power transmission mechanism comprising: a driving member rotatable both forward and backward; a driven member coaxial with the driving member; a first power transmission member movable in a first recess defined between the driving member and the driven member, the first power transmission member transmitting a forward driving force of the driving member to the driven member; and a second power transmission member movable in a second recess defined between the driving member and the driven member, the second power transmission member transmitting a backward driving force of the driving member to the driven member.
According to a third aspect of the invention, there is provide a camera comprising a power transmission mechanism that includes a driving member rotatable forwa
Sugita Yukihiko
Terada Hiroshi
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Olympus Optical Co,. Ltd.
Perkey W. B.
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