JP2946943B2 - Aperture control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture control device for a single-lens reflex camera.

[0002]

2. Description of the Related Art FIGS. 7 to 9 are schematic views showing an example of a conventional aperture control device. FIG. 7 shows a state before release.
FIG. 8 is a view showing a state in which the stop diameter is restrained and maintained, and FIG. 9 is a view showing a state in which the stop is opened again. In FIG. 7, the main mirror 1 is supported by a camera body (not shown) so as to be rotatable about an axis 3. The main mirror 1 is held in an inclined state as shown in FIG. 7 when observing the subject before the release, and guides the subject light from the lens to the viewfinder. To rotate up and retract from the subject light. The main mirror 1 is provided with a mirror driving pin 2.

[0003] The mirror / aperture drive lever 4 is provided with the main mirror 1.
And a lever for driving a diaphragm (not shown) provided on the lens side. The lever is rotatably supported by a camera body (not shown) about the axis 4d, and is urged counterclockwise by a spring 24. The mirror / aperture drive lever 4 includes a driven arm 4 a to which a driving force of a mirror / aperture drive motor 5 is transmitted, and a drive arm for driving the main mirror 1 via a mirror drive pin 2 provided on the main mirror 1. 4b and a reset arm 4c.

The mirror / aperture drive motor 5 is a motor for driving the main mirror 1 (up, down) and driving the aperture (stop down, aperture opening) by rotating forward and backward. The output shaft of the mirror / aperture drive motor 5 is provided with a lead screw 5a.
A meshing member 6 that moves left and right by forward and reverse rotation of the mirror / aperture drive motor 5 is screwed into a. When the engagement member 6 is moved rightward via the lead screw 5a by the rotation of the mirror / aperture drive motor 5, the main mirror 1 is moved.
Moves up, and conversely, when it moves to the left, the main mirror 1 goes down.

The camera-side aperture lever 7 is rotatably supported about a shaft 4d. This camera side aperture lever 7
Is engaged with the lens-side stop lever 8, and the position of the stop lever determines the aperture diameter of the stop provided on the lens side. Further, the camera-side aperture lever 7 is in contact with the intermediate lever 20 by the urging force of the spring 9. The lens-side aperture lever 8 is a lever interlocked with a lens-side aperture (not shown), and is urged downward by a spring 23.

FIG. 7 shows a state before the release, as described above. The camera-side aperture lever 7 and the lens-side aperture lever 8 are at the top dead center, and the apertures are in the open state.
As the lens-side aperture lever 8 moves downward from this state, the aperture diameter is reduced toward the smaller aperture side. The intermediate lever 20 is rotatably supported about the axis 4d, is disposed between the mirror / aperture drive lever 4 and the camera-side aperture lever 7, and has an internal force spring 9, 22 is in contact with the urging force.

Next, the operation of the aperture control device will be described. The shutter button (not shown) releases the mirror
When the aperture drive motor 5 rotates, the mirror / aperture drive lever 4 rotates clockwise, the main mirror 1 enters an up operation, and enters the state shown in FIG. On the other hand, when the mirror / aperture drive lever 4 rotates clockwise, the camera-side aperture lever 7
Rotate clockwise through spring 22 and intermediate lever 20,
Following this, the lens-side aperture lever 8 is lowered, so that the aperture in the lens is also reduced.

Next, when the completion of the raising of the main mirror 1 is detected and the mirror / aperture drive motor 5 is stopped, the shutter is activated and the exposure starts. Next, when the travel of the rear curtain of the shutter is detected to be completed, the mirror / aperture drive motor 5 starts reverse rotation, and the main mirror 1 enters a down operation. At this time, the main mirror / aperture drive lever 4
Rotates counterclockwise by the urging force of the spring 22, following the operation of the meshing member 6 (the state of FIG. 9). In addition,
Since the main mirror 1 is constantly biased clockwise by a down spring (not shown), the up / down operation is performed following the rotation of the main mirror / aperture drive lever 4.

The camera-side aperture lever 7 rotates counterclockwise integrally with the main mirror / aperture drive lever 4 via an inner spring 22, an intermediate lever 20, and an internal force spring 9, and follows the lens-side aperture. By raising the lever 8, the in-lens diaphragm is opened. When it is detected that the main mirror 1 has been restored to the tilt position before photographing or the aperture has been restored to the open position, the mirror / aperture drive motor 5 stops and the mirror down operation is completed.

Next, an aperture control system of the aperture control device will be described. When the shutter is released, the aperture control device measures and memorizes the brightness of the subject immediately before the shutter is released,
A combination of aperture and shutter speed values for giving proper exposure according to the luminance is set in advance, and proper exposure is given to the film surface by controlling each value to the set value.

The camera-side aperture lever 7 is provided with a gear 7a at a part thereof, and a speed-increasing gear 10 meshes with the gear 7a. The speed-increasing gear 10 rotates together with the ratchet pawl plate 11 to increase the locking resolution.

On the other hand, the locking lever 13 is rotatably supported about a shaft 13b, and has a locking claw 13a which engages with the ratchet claw 11a of the ratchet claw plate 11. A movable iron piece 14 is attached to the locking lever 13 by a shaft 14a.
It is supported so that it can swing around.

Before the release, the movable iron piece 14 is attracted to a fixed iron core 15 which is a permanent magnet, as shown in FIG. The fixed iron core 15 is provided with a coil 16, and by applying a pulse current to the coil 16,
The fixed iron core 15 is demagnetized. When the lens-side aperture lever 8 is driven to a preset aperture, the coil 16
When the fixed iron core 15 is demagnetized by applying a pulse to the movable iron piece 14, the movable iron piece 14 is released from the attraction as shown in FIG. 8 because the locking lever 13 is urged clockwise by the spring 13c. .

At the same time, since the locking claw 13a of the locking lever 13 engages with the ratchet claw 11a, the movement of the lens-side aperture lever 8 is restricted, and the aperture is maintained in that state. In order to release this maintenance state and return the aperture to the open diameter, the movable iron piece 14 must be attracted to the fixed iron core 15 again to release the engagement between the locking claw 13a and the ratchet claw 11a. . This operation is called reset,
A reset lever 17 is provided to perform this reset operation.

The reset lever 17 is a fly lever supported rotatably about a shaft 17a.
When the fixed iron core 4 and the fixed iron core 15 are in a non-adsorbed state (the state shown in FIG. 8), the mirror and the aperture driving lever 4 abut on the reset arm 4c. The reset assist lever 18 is rotatably supported by a shaft 17 a, and an internal force spring 19 is hung between the reset assist lever 18 and the reset lever 17. When the mirror is raised, the reset lever 17 rotates counterclockwise, passes through the reset arm 4c, returns to the original position, and waits.

On the other hand, when the mirror is down, the reset lever 17 rotates clockwise while engaging with the reset arm 4c as shown in FIG. At this time, the reset auxiliary lever 18 rotates integrally with the reset lever 17,
As shown in FIG. 9, the locking lever 13 engaged at the tip thereof is rotated counterclockwise to rotate the ratchet pawl 11a.
And the movable iron piece 14 is re-adsorbed to the fixed iron core 15.

Since the reset lever 17 rotates even after the movable iron piece 14 and the fixed iron core 15 are re-adsorbed, the reset lever 17 needs to rotate enough to absorb the over-rotation amount. Therefore, the lever 18 is configured to be reset by the internal force spring 19. Due to the release of the lock, the aperture maintained by the lock claw 13c moves to the open side by the urging force of the spring 23 and returns.

[0018]

However, in the above-mentioned conventional aperture control apparatus, the reset operation for returning the aperture to the open diameter is performed in a short period of time during one reciprocation of the mirror / aperture drive lever. Since the rotation must be performed by the flywheel mechanism using a flywheel lever whose biasing direction is reversed at the intermediate passing point, the rotation angle until the flywheel lever reverses becomes large, and the rotation of the mirror / aperture drive lever There was a problem that the corner became large. Conversely, when trying to reduce the rotation angle of the mirror / aperture drive lever, the amount of engagement with the fly lever must be extremely reduced, causing unstable operation. In addition, there is a problem that the contact diameter of the fly lever must be reduced, and there is a large restriction on the configuration. Also, at the time of reset, the movable iron piece 14 is fixed to the fixed iron core 15.
However, the re-suction operation is unstable.

An object of the present invention is to provide an aperture control device for a single-lens reflex camera, which can stably reset without using a flywheel mechanism.

[0020]

In order to solve the above-mentioned problems, an aperture control apparatus according to the present invention includes a mirror / aperture driving means (201) for driving a mirror and an aperture, and interlocking with the mirror / aperture driving means. Aperture position setting means (215, 211) for setting the aperture position; and aperture position maintaining means (203) engaged with the aperture position setting means and urged to maintain the aperture position. Reset means (20) for releasing the engagement between the aperture position setting means and the aperture position maintaining means in conjunction with the mirror / aperture drive means.
2) and suction means (205) provided in the reset means for suction-holding the aperture position maintaining means,
During mirror elevating stroke of the mirror diaphragm drive means, the said stop position determination, and maintained by engagement with the throttle position setting means the throttle position maintaining means releases the suction of the suction means, followed the Mirror / aperture drive means
During the ascending movement of the mirror, the suction means and the aperture position maintaining means are pressed against each other to be adsorbed again, thereby completing the ascending movement of the mirror.
And, in the mirror downward stroke of the mirror diaphragm control means,
The suction means is in a suction state with the throttle position maintaining means.
It is constituted to release the engagement between the diaphragm position setting means by for moving some said reset means.

[0021]

According to the present invention, at the end of the mirror ascent stroke, the suction means is brought closer to the aperture position maintaining means to re-adsorb it, and during the mirror descent stroke, the reset means is moved to move the suction means. The aperture position maintaining means sucked by the above is retracted together to release the engagement with the aperture position setting means, so that a stable reset can be performed without using a flywheel mechanism.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings and the like.
This will be described in more detail. (Embodiment 1) FIGS. 1 to 3 are schematic views showing a first embodiment of an aperture control device according to the present invention. FIG. 1 shows a state before release, and FIG. FIG. 3 is a diagram showing a state at the time of completion of mirror up. The basic configuration of the aperture control device of this embodiment is almost the same as that of the conventional example shown in FIGS. 7 to 9, and therefore, the description will focus on the configuration and operation different from those of the conventional example.

The mirror / aperture drive lever 201 is
The mirror is supported rotatably about 1d.
The aperture drive lever 201 has a cam surface 201a. The cam surface 201a includes a large-diameter portion 201b and a small-diameter portion 201c, and a roller 208 provided at one end of the fixed iron lever 202 is in contact with the cam surface 201a. The large diameter portion 201b and the small diameter portion 201c are
Both are arc surfaces centered on the axis 201d.

The fixed iron core lever 202 and the throttle locking lever 203 are supported so as to be independently rotatable about a shaft 203a. The fixed iron core lever 202 is provided with a fixed iron core 205 which is a permanent magnet, and the aperture locking lever 203 is provided with a movable iron piece 204 which can swing about a shaft 204a. A spring 206 is hung between the fixed iron core lever 202 and the aperture locking lever 203 to urge the aperture locking lever 203 clockwise. Before the movable iron piece 204 is released (the state shown in FIG. 1), the movable iron piece 204 is attracted to the fixed core 205, and during the aperture control (the state shown in FIG. 2), the movable iron piece 204 and the fixed iron core 205 are attracted. The aperture is released, the aperture locking lever 203 is rotated clockwise by the urging force of the spring 206, and the locking claw 203b locks the ratchet claw plate 211, thereby controlling the aperture.

A roller 208 is rotatably provided at the left end of the fixed iron core lever 202, and is in contact with the cam surface 201 a of the mirror / aperture drive lever 201. A spring 207 is hung on the right end of the fixed iron core lever 202, and the fixed iron core lever 202 and the aperture locking lever 203 are urged clockwise by the spring 207. In this state, the locking claw 203b of the aperture locking lever 203
And the ratchet claw plate 211 are determined. This interval is always kept constant up to the minimum stop during mirror driving.

Next, the operation of the aperture control of the first embodiment will be described. Before the release, as shown in FIG. 1, the movable iron piece 204 is attracted to the fixed iron core 205. mirror·
According to the rotation of the aperture drive motor 209, the meshing member 2
10 moves to the right and the mirror / aperture drive lever 201
When clockwise rotates, the main mirror 212 starts the up operation. With the rotation of the mirror / aperture drive lever 201, the lens-side aperture lever 213 is moved from the state of FIG. 1 to the preset aperture via an intermediate lever 215 connected to the mirror / aperture drive lever 201 by an inner spring 216. When the coil 214 is driven, a pulse current is applied to the fixed iron core 205 to demagnetize the fixed iron core 205. Since the aperture locking lever 203 is rotated clockwise by the urging force of the spring 206, the movable iron piece 204 As shown, it is released from adsorption. At the same time, the locking claw 203b of the stop locking lever 203 is engaged with the ratchet pawl plate 211, so that the movement of the lens-side stop lever 213 is restricted, and the stop is maintained in that state.

When the mirror / aperture drive lever 201 is further rotated clockwise from the state shown in FIG. 2, the up operation of the main mirror 212 is completed, and the state shown in FIG. 3 is obtained. At this time,
The roller 208 provided on the fixed iron core lever 202 is brought into contact with the cam surface 201a by the urging force of the spring 207 hung on the fixed iron core lever 202, and the large diameter portion 201b
To the small diameter portion 201c. And the fixed iron core 20
5 is re-adsorbed to the movable iron core 204, and the transition to the reset becomes possible. The mirror stroke of the mirror / aperture drive lever 201 is set to be larger than the aperture drive (open to minimum aperture) stroke. Also, the cam surface 201
Since the large-diameter portion 201b of a is a concentric circular surface, the fixed iron core lever 202 is held at the same position until the minimum aperture.

Next, when the completion of the mirror up is detected, the shutter operates to perform exposure, and when the completion of the exposure is detected, the mirror down is started. At this time, the mirror / aperture drive motor 209 rotates in the reverse direction, and the meshing member 210 moves to the left. The mirror / aperture drive lever 201 rotates counterclockwise following the movement of the engagement member 210, so that the main mirror 212 performs a down operation.

On the other hand, as the mirror / aperture drive lever 201 rotates counterclockwise, the movable iron piece fixed iron core lever 20 is rotated.
The second roller 208 moves from the small diameter portion 201 c to the large diameter portion 201.
Move to b. At this time, the movable iron core 205 and the fixed iron core 2
Since the apertures 04 rotate integrally in the sucked state, the engagement between the aperture locking lever 203 and the ratchet pawl plate 211 is released, and the aperture is opened (the state of FIG. 1).

As described above, the aperture control device of the first embodiment can stably reset without using the flywheel mechanism.

(Embodiment 2) FIGS. 4 to 6 are schematic diagrams showing a second embodiment of the aperture control device according to the present invention. FIG. 4 shows a state before release, and FIG. The state,
FIG. 6 is a diagram showing a state at the time of completion of mirror up. Second
The basic configuration of the aperture control device of this embodiment is almost the same as that of the first embodiment described above, and the method of re-adsorbing the movable iron piece and the fixed iron core is different. Will be described.

The mirror / aperture drive lever 301 is
The mirror is supported rotatably about 1d.
The aperture driving lever 301 has a cam surface 301a. The cam surface 301a includes a small diameter portion 301b and a large diameter portion 301c, and a roller 308 provided at one end of the fixed iron lever 302 is in contact with the cam surface 301a.

Fixed iron core lever 302, aperture locking lever 3
03 and the cam lever 320 are supported so as to be independently rotatable about a shaft 303a. The fixed iron core lever 302 is provided with a fixed iron core 305 which is a permanent magnet, and the aperture locking lever 303 is provided with a movable iron piece 304 which is swingable about a shaft 304a.

The cam lever 320 is rotatably supported about a shaft 303a, and has a roller 30 at its tip which comes into contact with the cam surface 301a of the mirror / aperture drive lever 301.
8 are provided. A spring 322 is hung between the cam lever 320 and the fixed iron core lever 302, and the cam lever 320 is urged clockwise by the spring 322. Therefore, the cam lever 320
Are biased in the direction in which they come into contact with the cam surface 301a of the mirror / aperture drive lever 301. The fixed iron core lever 302 has a cam lever 31.
5 are provided.

Fixed iron core lever 302 and aperture locking lever 3
A spring 306 is hung between the lever and the lever 03 to urge the aperture locking lever 303 counterclockwise. A spring 307 is hung on the left end of the fixed iron core lever 302 to urge the fixed iron core lever 302 counterclockwise.

Next, the operation of the aperture control of the second embodiment will be described. Before the release, as shown in FIG. 4, the movable iron piece 304 is attracted to the fixed iron core 305. mirror·
According to the rotation of the aperture drive motor 309, the meshing member 3
10 moves to the right and the mirror / aperture drive lever 301
When rotates clockwise, the main mirror 312 starts the up operation. When the lens-side aperture lever 313 is driven from the state shown in FIG. 4 to the preset aperture with the rotation of the mirror / aperture drive lever 301, when a pulse current is applied to the coil 314 and the fixed iron core 305 is demagnetized, Since the aperture locking lever 303 is rotated counterclockwise by the urging force of the spring 306, the movable iron piece 304 is released from the suction as shown in FIG. At the same time, the locking claw 303b of the aperture locking lever 303 is
Since the lens 11 is engaged, the movement of the lens-side aperture lever 313 is restricted, and the aperture is maintained in that state.

When the mirror / aperture drive lever 301 further rotates clockwise from the state shown in FIG. 5, the up operation of the main mirror 312 is completed, and the state shown in FIG. 6 is obtained. At this time,
The roller 308 provided on the cam lever 320 is brought into contact with the cam surface 301 a by the urging force of a spring 322 hung between the roller 308 and the fixed iron core lever 302, and the small-diameter portion 301
b to the large diameter portion 301c. And fixed iron core 3
05 re-adsorbs to the movable iron core 304 to enable a transition to reset.

Next, when the completion of the mirror up is detected, the shutter operates to perform the exposure, and when the completion of the exposure is detected, the mirror down is started. At this time, the mirror / aperture drive motor 309 rotates in the reverse direction, and the meshing member 310 moves to the left. Following the movement of the meshing member 310, the mirror / aperture drive lever 301 rotates counterclockwise, so that the main mirror 312 performs a down operation.

On the other hand, as the mirror / aperture drive lever 301 rotates counterclockwise, the roller 3
08 moves from the large diameter portion 301c to the small diameter portion 301b. At this time, since the movable iron core 305 and the fixed iron core 304 rotate integrally while being attracted, the engagement between the aperture locking lever 303 and the ratchet pawl plate 311 is released,
The aperture is opened (state of FIG. 4). In addition, by providing the cam cover 320, compared with the case where the reset is performed by the difference in the strength of the spring in the first embodiment,
Since the driving force of the motor can be used at the time of resetting, reliability is improved.

[0040]

As described above in detail, according to the present invention, a stable reset operation can be performed without using a flywheel mechanism. For example, the conventional inconvenience that the rotation angle of the mirror / aperture drive lever is increased or the operation becomes unstable when the rotation angle is reduced is eliminated.

Further, since the suction means is sufficiently brought close to the aperture maintaining means in the latter stage of the mirror ascent stroke to perform suction, the operation is not instantaneous as in the prior art. Problems such as variations in time are eliminated.

Further, since the reset operation can be performed in the early stage of the mirror lowering process, the mirror down time is not affected unlike the related art.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first embodiment (before release) of an aperture control device according to the present invention.

FIG. 2 is a schematic diagram showing a first embodiment (at the time of aperture control) of the aperture control device according to the present invention.

FIG. 3 is a schematic diagram showing a first embodiment (at the time of reset) of the aperture control device according to the present invention.

FIG. 4 is a schematic diagram showing a second embodiment (before release) of the aperture control device according to the present invention.

FIG. 5 is a schematic view showing a second embodiment (at the time of aperture control) of the aperture control device according to the present invention.

FIG. 6 is a schematic diagram showing a second embodiment (at the time of reset) of the aperture control device according to the present invention.

FIG. 7 is a diagram illustrating an example of a conventional aperture control device (before release).

FIG. 8 is a diagram illustrating an example of a conventional aperture control device (during aperture control).

FIG. 9 shows an example of a conventional aperture control device (reset state).
FIG.

[Explanation of symbols]

 201, 301 Mirror / aperture drive lever 201a, 301a Cam surface 202, 302 Fixed iron core lever 203, 303 Aperture lock lever 204, 304 Movable iron piece 205, 305 Fixed iron core 320 Cam lever 321 Pin 322 Spring

Claims (1)

(57) [Claims] 1. A mirror for driving a mirror and a diaphragm.
Aperture drive means, Aperture position setting means for setting an aperture position in conjunction with the mirror / aperture drive means, Energized with the aperture position setting means, and biased to maintain the aperture position. Aperture position maintaining means; reset means for releasing engagement between the aperture position setting means and the aperture position maintaining means in conjunction with the mirror / aperture drive means; provided in the reset means; A suction means for sucking and holding the means, during the mirror raising stroke of the mirror / aperture drive means, releasing the suction of the suction means and engaging the aperture position maintaining means with the aperture position setting means. The aperture position is determined and maintained, and the mirror and aperture drive means
During the ascending movement of the mirror, the suction means and the aperture position maintaining means are pressed against each other to be adsorbed again, thereby completing the ascending movement of the mirror.
And, in the mirror downward stroke of the mirror diaphragm control means, wherein
Throttle control device, characterized in that to release the engagement with the throttle position setting means by for moving the <br/> said reset means is in the attracted state with the throttle position maintaining means by suction means.