Photography – With exposure objective focusing means – focusing aid – or... – Dual purpose motor
Reexamination Certificate
2001-07-31
2003-03-04
Gray, David M. (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Dual purpose motor
C396S358000, C396S418000
Reexamination Certificate
active
06529688
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving device for driving a plurality of driving systems using a plurality of motors as a driving source, an apparatus having the driving device, and a camera.
2. Description of the Related Art
Some single-lens reflex cameras use motors as a driving source to drive a mirror driving system, a shutter charge driving system, a film winding or rewinding driving system, an electronic flash pop-up or -down driving system, and the like.
For example, a camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 3-75626 incorporates two motors disposed such that the first motor is rotated in one direction to wind a film and in the other direction to drive a mirror and a shutter, whereas the second motor is rotated in one direction to rewind the film and in the other direction to drive an electronic flash.
Further, various cameras have been proposed which use one motor as a driving source to feed the film, charge the shutter, drive the mirror, and so on.
For example, a camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 1-202731 employs a preliminary winding system wherein the camera main body incorporates one motor disposed such that when a user opens a rear cover, charges a film cartridge into the camera, and then closes the rear cover, a full-amount winding spool winds a film in the film cartridge to set the camera in a photographing standby state. Thereafter, in photographing, this motor is used to rewind the film, charge the shutter, and drive the mirror through switching of a planetary clutch.
In this camera, when the motor is rotated in one direction, the planetary clutch is connected to a first transmission system on a film winding side, and as the motor continues to rotate in the same direction, the film is wound. Once the winding operation is completed, the motor is rotated in the other direction to connect the planetary clutch to a second transmission system. When the motor is rotated in the other direction with the planetary clutch connected to the second transmission system, a series of photographing operations including film rewinding, mirror popping-up and -down, and shutter charging are performed while a rotary cam member makes a turn.
Further, a motor driving device proposed in Japanese Laid-Open Patent Publication (Kokai) No. 1-287648 drives a plurality of planetary clutch mechanisms using one motor. The motor is rotated in one direction to cause a first planetary clutch to perform a switching operation to select a driving system to which power is transmitted when the motor rotates in the other direction. Once the driving system is selected in this manner, the motor is rotated in the other direction to transmit motor power to the selected driving system.
Moreover, a camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 8-328094 drives a plurality of planetary clutch mechanisms using one motor. The motor is rotated in one and the other directions to perform a series of photographing operations including mirror driving, shutter charge driving, and film winding, followed by performing a phase indexing operation for an electronic flash popping-up operation to be performed as a photographing preparing operation.
Further, a camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 7-270877 uses a motor that drives a taking lens barrel to distribute power to other motors.
Moreover, a camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 61-269129 includes a film winding mechanism having two types of gear ratios for high-speed winding and low-speed winding, which are switched depending on load, power supply, or the like or to switch from the low-speed winding to the high-speed-winding for preliminary winding.
However, in the camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 3-75626, the two motors each carry our the film driving, mirror driving, and shutter charge driving, but since these driving systems undergo relatively heavy driving loads, large-sized motors of high power are employed for these motors if a camera having a high continuous photographing speed is to be provided. Thus, the camera will be expensive and large in size.
Further, the camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 2-202731 uses only one motor, thus making it possible to reduce its own size. The use of the preliminary film winding system, however, requires a rear cover interlocking mechanism and the like, thereby hindering the entire system or layout from being designed freely.
Moreover, the motor driving device proposed in Japanese Laid-Open Patent Publication (Kokai) No. 1-287648 also uses only one motor, but it requires as many planetary clutches as the number of the driving systems to which power is transmitted, thus requiring a large-sized mechanism. Further, since one operation is completed by a set of rotations of the motor in one and the other directions, a complicated sequence is required for a series of plural operations. If this motor driving device is applied to a camera, the continuous photographing speed will be low.
Furthermore, the camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 8-328094 uses only one motor, but the cam member for causing the series of photographing operations including mirror driving and shutter charge driving to be performed during one rotation thereof is provided with phases for phase indexing that allow the electronic flash to pop up after photographing operation has been completed. Consequently, this camera is not optimal for increasing the continuous photographing speed.
Further, the camera proposed in Japanese Laid-Open Patent Publication (Kokai) No. 7-270877 determines driving force transmitting paths for the motors other than the one for driving the lens barrel, based on a position in which the lens barrel is stopped, thereby hindering the driving force transmitting paths used from being selected freely.
With respect to the film winding operation, which significantly affects the speed of the continuous photographing operation, the load required for film winding varies with the type of the commercially available film. Further, at low temperature, the film winding load increases, so that the gear ratio of the film winding mechanism must be set to such a gear ratio as can deal with a high load of about 800 g. Consequently, the film winding speed necessarily decreases in normal photographing.
Furthermore, in all the above conventional constructions, the gear ratio of the film winding mechanism is set to a single gear ratio, thus limiting an increase in the continuous photographing speed.
To cope with this problem, the camera proposed in Japanese Laid-open Patent Publication (Kokai) No. 61-269129 is provided with a winding mechanism having two gear ratios for high and low speeds. However, it requires an exclusive motor for winding the film. Further, other relatively large-sized motors are required for driving mechanisms for mirror driving, shutter charging, film rewinding, and others which deal with relatively heavy loads. Thus, the camera has to be large in size.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a driving device and a camera which are compact in size and inexpensive even with the use of two motors, which allow relevant mechanisms to be laid out freely to thereby simplify motor controlling sequences, and which allow the user to quickly perform preliminary winding of a newly loaded film after film rewinding to thereby minimize the effects of film replacement during photographing, as well as an apparatus having the driving device.
It is a second object of the present invention to provide a driving device and a camera which are capable of performing optimal and efficient driving according to driving loads or the like, that is, allow the user to select an optimal driving speed, as well as an apparatus having the driving device.
To attain the above objects, a first aspect of the present invention provides
Kaihara Shoji
Yamagami Shigeru
Canon Kabushiki Kaisha
Gray David M.
Robin Blecker & Daley
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