Photography – Having variable focal length of camera objective – Power zoom
Reexamination Certificate
1999-10-20
2001-04-03
Perkey, W. B. (Department: 2851)
Photography
Having variable focal length of camera objective
Power zoom
C396S349000, C396S448000
Reexamination Certificate
active
06212335
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a driving mechanism of a lens barrier and zoom lens for a camera provided with a zooming mechanism.
Recent compact cameras are provided with zooming mechanisms. A zooming mechanism is constructed such that a driving force of a zoom motor is transmitted through a zoom gear train to a lens drive mechanism for driving a lens in a direction of the optical axis.
On the other hand, compact cameras are generally provided with lens barrier mechanisms. A lens barrier mechanism is provided with a lens barrier which is movable between a close position and an open position. When the lens barrier is located at the close position, the lens barrier is positioned in front of the lens to cover the same, while when the lens barrier is located at the open position, the lens barrier is completed retracted from the close position.
In order to reduce a manufacturing cost, it is preferable that the both mechanisms are driven by a single motor.
However, if the both mechanisms are merely connected to a single drive source, when the lens barrier mechanism is being driven, the zoom lens should not be driven, and when the zooming mechanism is being driven, the lens barrier should not be driven. Therefore, in both mechanism, extra strokes for not driving the zoom lens and the lens barrier should be provided, which increase the size of a camera.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved lens barrier mechanism which opens/closes a lens barrier using a driving force of a zoom motor, and still enables downsizing and cost-reduction of a camera.
For the above object, according to the invention, there is provided a driving mechanism of a barrier and a zoom lens for a camera which is provided with: a zooming mechanism for moving the zoom lens; a barrier opening/closing mechanism; a motor; a first gear train connected to the motor; a second gear train connected to the zooming mechanism; a planetary gear mechanism including a sun gear, a first arm rotatable about the rotation axis of the sun gear, a planetary gear rotatably supported by the first arm, the planetary gear engaging the sun gear, a barrier drive gear fixed to the first arm, rotation axis of the barrier drive gear coincides of the rotation axis of the first arm, the sun gear being connected to the first gear, the planetary gear being movable between a first and second positions, the planetary gear being engaged with the second gear train when located at the second position and disconnected therefrom when moved away from the second position, the barrier drive gear being connected to the barrier opening/closing mechanism, the barrier opening/closing mechanism being driven when the planetary gear moves between the first and second positions.
Optionally, the barrier mechanism may further include an engaging mechanism that is engaged with the first arm to stay at the second position.
Further, the camera is provided with a lens barrel that can be located at a retracted position or a position within a zooming area, and the engagement between the engaging mechanism with the first arm is released when the lens barrel is located in the zooming area.
Specifically, the planetary gear mechanism is further provided with an arch-shaped inner threaded gear on an outside, in a radial direction of the sun gear. The planetary gear engages the arc-shaped inner threaded gear when the planetary gear is located at an any point between an intermediate position, which is a position between the first and second positions, and the first position. The engagement between the planetary gear and the inner threaded gear is released when the planetary gear is located at the second position.
Further, the barrier is located at the close position when the planetary gear is located at the first position, wherein the barrier is located at the open position when the planetary gear is located at a position between the intermediate position and the second position.
When the camera is powered ON, the motor is driven to move, through the first gear train, the planetary gear from the first position to the second position via the intermediate position, and thereafter to drive, through the second gear train, the zooming mechanism to move the zoom lens from the retracted position to the wide extremity.
Further, when the camera is powered OFF, the motor is driven to move, through the second gear train and zooming mechanism, the zoom lens to the retracted position, and thereafter, to move the planetary gear from the second position to the first position via the intermediate position.
Optionally, the engaging mechanism engages the first arm to stay at the second position only when the zoom lens is located at the retracted position, the engagement between the first arm and the engaging mechanism being released when the zoom lens is moved from the retracted position to the wide extremity.
Further optionally, the engaging mechanism includes a movable rod which extend in a direction parallel to the optical axis of the zoom lens and is movable in the direction of the optical axis. The movable rod is engaged with an engaging portion formed on the first arm to prevent the first arm from rotating.
In this case, if the motor is driven such that the barrier is moved from the open position to the close position when the lens barrel is located at the wide extremity, the engagement between the barrier and the barrier mechanism is released when the planetary gear moves from the intermediate position to the first position.
Optionally, the barrier mechanism includes a gear train which is driven when the first arm is rotated, and a second arm which is connected to the barrier, one gear included in the gear train is formed with a sector-shape opening, the second arm being provided with an engaging portion which is to be engaged with the sector-shape opening, the second arm being rotated by the one gear when the engaging portion contacts an end of the sector-shaped opening.
Further, the barrier and the second arm are connected by a spring, the spring urges the barrier to move toward the close position when the barrier is located in the vicinity of the close position, and the spring urges the barrier to move toward the open position when the barrier is located in the vicinity of the open position.
According to another aspect of the invention, there is provided a camera, provided with: a zoom lens; a barrier for covering/exposing the zoom lens; a zooming mechanism for driving the zoom lens to move in a direction of an optical axis of the zoom lens; a barrier mechanism for driving the barrier to open/close the zoom lens; a motor; a first gear train connected to the motor; a second gear train connected to the zooming mechanism; a planetary gear mechanism including a sun gear, a first arm rotatable about the rotation axis of the sun gear, a planetary gear rotatably supported by the first arm, the planetary gear engaging the sun gear, a barrier drive gear fixed to the first arm, rotation axis of the barrier drive gear coincides of the rotation axis of the first arm, the sun gear being connected to the first gear train, the planetary gear being movable between a first and second positions, the planetary gear being engaged with the second gear train when located at the second position and disconnected therefrom when moved away from the second position, the barrier drive gear being connected to the barrier opening/closing mechanism, the barrier opening/closing mechanism being driven when the planetary gear moves between the first and second positions.
REFERENCES:
patent: 5461441 (1995-10-01), Kotani
patent: 5617167 (1997-04-01), Kaji
patent: 5708884 (1998-01-01), Morishita
patent: 5822634 (1998-10-01), Morishita
patent: 5842057 (1998-11-01), Nomura et al.
patent: 5892996 (1999-04-01), Yokota
patent: 5950028 (1999-09-01), Ito
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Perkey W. B.
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