Photography – With film drive – Mechanical detail
Reexamination Certificate
1999-06-23
2001-11-13
Gray, David M. (Department: 2851)
Photography
With film drive
Mechanical detail
C396S418000, C192S089270, C192S203000
Reexamination Certificate
active
06315466
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clutch unit for selectively transmitting driving force to a camera film feeder.
2. Description of the Related Art
Conventional clutch units for selectively transmitting driving force are unidirectional. Torque exerted to rotate a driving shaft in one direction is transmitted to a driven shaft, however no torque is exerted to produce rotation in an opposite direction.
A one-way clutch unit adapted for film feeding in a camera is disclosed in U.S. Pat. No. 5,136,314 and shown in FIG.
12
.
In the film feeding mechanism, driving force from a drive motor
103
is transmitted to a sun gear
106
of an epicyclic gear mechanism via a pinion
104
and gear train
105
. An epicyclic gear
107
meshes with a driven gear
108
or a driven gear
109
.
The driven gear
108
is coupled to a gear
102
a
of a spool shaft
102
via a spool gear train
111
. The driven gear
108
meshes with an input gear
110
a
of a one-way clutch
110
. An output gear
110
b
of the one-way clutch
110
is coupled with a cartridge driving gear
113
via a cartridge gear train
112
. The cartridge driving gear
113
has a fork portion
113
a
received in a cartridge shaft
114
. As discussed throughout, direction D
13
shall be a direction of normal rotation in which the one-way clutch
110
rotates normally to drive.
When the film feeding mechanism is used to feed a film
120
, the driven gear
108
is rotated in a direction D
11
via the epicyclic gear mechanism. The cartridge driving gear
113
is rotated via the one-way clutch
110
and gear train
112
. Consequently, the film
120
is advanced. At the same time, the spool shaft
102
is driven via the spool gear train
111
. After the film
120
is advanced, when the film is wound by rotating the spool shaft
102
, the film is maintained in tension. An advancing rate at which a film is advanced from the spool shaft is greater than an advancing rate at which the film is advanced from the cartridge. Therefore, the cartridge driving gear
113
is rotated quickly. The output gear
110
b
of the one-way clutch
110
is driven in the direction D
13
relatively faster than the input gear
110
a
. This state shall be referred to as an overrunning state. For photography, film is wound in this manner, that is, with the spool shaft driven faster.
To rewind film, the motor
103
is rotated reversely in order to cause the epicyclic gear
107
to mesh with the gear
109
. The driven gear
109
is rotated in a direction D
12
via the epicyclic gear mechanism. The output gear
110
b
of the one-way clutch
110
is driven to rotate in a direction opposite to direction D
13
. The cartridge driving gear
113
is driven in an opposite direction via the gear train
112
. The film
120
is rewound about the cartridge shaft. The spool shaft
102
is rotated in a direction opposite to a direction of arrow F in
FIG. 12
of the film
120
.
The film feeding mechanism for a camera disclosed in the U.S. Pat. No. 5,136,314 employs the one-way clutch
110
for driving the spool shaft and cartridge shaft with the spool shaft interlocked with the cartridge shaft. However, the input driving gear of the one-way clutch
110
cannot drive for rotation in both directions. For rewinding the film
120
, the output gear
110
b
must be driven directly as shown in FIG.
12
. For a driving system capable of driving in both the directions, another driving system for directly driving the output gear
110
b
must be added. Moreover, since the one-way clutch
110
must be interposed between the cartridge driving system and spool driving system, it requires significant sufficient space for the components and leads to a complex mechanism.
Moreover, a film feeding and driving system including the one-way clutch
110
must be positioned as a unit on the bottom or top of a camera body, resulting in ineffective use of a large space for the film feeding and driving system in the camera body.
SUMMARY OF THE INVENTION
The present invention attempts to resolve the above drawbacks. An object of the present invention is to provide a clutch unit capable of transmitting driving shaft rotational force to a driven shaft. The clutch unit provides great freedom for positioning the clutch unit.
Another object of the present invention is to provide a camera in which a clutch unit for switching drives is located at an appropriate position in a film feeding and driving system in the camera. The camera can therefore be downsized or designed compactly.
A clutch unit in accordance with one aspect of the present invention has a driving shaft, a driven shaft, and a coil spring. The driving shaft can be driven to rotate in both directions. The driven shaft is located coaxially with the driving shaft. The coil spring is used to transmit rotation of the driving shaft. The coil spring has an arm portion capable of engaging with the driving shaft and a coil portion that frictionally engages with the driven shaft. The coil spring transmits force to the driven shaft regardless of the direction in which the driving shaft is rotated. Driving force rotating the driving shaft in both directions can be transmitted to the driven shaft.
According to the clutch unit of the invention, driving shaft rotation in either direction can be transmitted to the driven shaft. The present clutch unit for a driving system expands designer freedom to position the clutch unit in a camera.
A camera according to another aspect of the present invention comprises a film cartridge chamber, a film wind chamber, a photographic lens barrel, and a clutch unit. A film cartridge having a cartridge shaft about which a film is wound is loaded in the film cartridge chamber. The film wind chamber has a film wind shaft about which film advanced from the film cartridge is wound. The photographic lens barrel is interposed between the film cartridge chamber and film wind chamber. The photographic lens barrel has an optical axis in a direction substantially perpendicular to an exposure screen mask. The clutch unit defines a transmitted state and a non-transmitted state for selectively transmitting power to a cartridge shaft, respectively. In the transmitted state, driving force exerted from a drive source is transmitted to the cartridge shaft in the film cartridge so that a film is advanced from the film cartridge. In the non-transmitted state, driving force exerted from the drive source is not transmitted to the cartridge shaft. The non-transmitted state is established when the film is wound about the film wind shaft and fed after film advanced from the film cartridge reaches the film wind shaft in the film wind chamber. The clutch unit is located in a space created between the film cartridge chamber and the photographic lens barrel or between the film wind chamber and the photographic lens barrel.
According to the camera of the present invention, the clutch unit for selectively transmitting power can be located at an appropriate position in a film feeding and driving system in the camera. The camera can therefore be downsized or designed compactly.
REFERENCES:
patent: 4372432 (1983-02-01), Waine et al.
patent: 5136314 (1992-08-01), Kazima et al.
Kitahara Yoshiyuki
Sugita Yukihiko
Takahashi Shinya
Terada Hiroshi
Tsuchida Naohiro
Gray David M.
Olympus Optical Co,. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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