JPH0291625A - camera shutter - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a double light shielding mechanism of a camera shutter such as a focal plane shutter.

[Conventional technology]

Conventionally, in focal plane shutters, there have been so-called double light-shielding shutters in which an aperture is blocked by both a front curtain group and a rear curtain group in order to increase light-blocking performance.

One type of double-shading shutter is a type in which the leading curtain group is moved to a position covering the aperture immediately after exposure ends, while the trailing curtain group remains covering the aperture. It was a structure that would be released.

However, in recent years cameras are generally equipped with a built-in motor drive device, and the winding operation is performed immediately after shooting, so with this type of double light-shielding shutter, the double light-shielding is released immediately after shooting is completed. Because of this, the meaning of shading has diminished.

Another type of double light-shielding shutter is suitable for cameras with a built-in motor drive device. After shooting, the rear blade group is held in a position covering the aperture and charged, and the leading blade group is charged. In this method, charging is completed at this point, that is, when the leading blade group also covers the aperture, and the camera waits for the camera release operation. Next, when the release operation is performed, the rear blade group that was held in a position covering the aperture is released, and after the rear blade group has retreated from the aperture, the leading blade group and the rear blade group move at a predetermined timing in that order. This completes the exposure.

However, this latter type of shutter also causes inconveniences in the following cameras.

In other words, in a camera, the time from when the photographer operates the release until the actual shooting is performed is
This is called a time lag, but the smaller the release time lag, the closer the photographer can take a photo to the moment he or she intended to take the photo. Especially in sports photography and race photography, the release time lag can be a major obstacle to capturing the decisive moment. However, in the latter type of shutter mentioned above, the trailing blade group is retracted after the release operation, so the time it takes for the trailing blade group to retract and the time it takes for the retracted trailing blade group to stabilize is added to the release time lag. , making it unsuitable for capturing decisive moments. It is conventionally known that in order to shorten the release time lag, the reflex mirror is fixed and the time required for the mirror's retracting movement is eliminated. Shutters cannot be incorporated in practice.

Therefore, it is possible to perform the retraction operation of the rear blade group before the release operation, and prevent the time for the retraction operation of the rear blade group from being added to the release time lag. If you cancel the release operation after doing this (when you wanted to take a picture but decided not to do so because it was not a good scene), in order to make the shutter double light shield again, you need to wait until the rear blade group has completed its travel. You have to create a state. In other words, only the trailing blade group is caused to run in the same manner as in a normal relay, thereby creating a state in which the trailing blade group has completed running. After that, the charging operation is performed again to return to the double light shielding state. However, in this type of operation, the blade group continues to move even though shooting has been stopped, so a sound that sounds as if a photo has been taken may be emitted after the release operation is released, confusing the photographer, or the rear blade group may be distorted. Because the camera had to run at times other than normal shooting, if this happened repeatedly, there was a possibility that an accident could occur, such as damage to the rear blade group.

[Means for solving problems]

Therefore, in the present invention, the release operation can be canceled in a camera that can shorten the release time lag by canceling the double light shielding before the release operation so that it can be applied to a camera with a built-in motor drive that undergoes double light shielding when charging is completed. By using a shutter that can form a double light-shielding state without emitting the running sound of the rear blade group as in the conventional example, it is possible to prevent the release from occurring even if shooting has been stopped. To provide a double light-shielding shutter for a camera that does not cause accidents such as damage to the rear blade group.

〔Example〕

Embodiments of the present invention are shown in FIGS. 1 to 6.

In the figure, 1 is a shutter base plate that has a rotating shaft and aperture such as a charge lever and a drive lever, and 2 is a charge lever that charges the shutter by rotating clockwise and is biased from outside by a charging member (not shown). 2
a, 2b, 2c.

It has a gear part 2d and a stop leg 2e. 3 is the leading blade group 10
A leading blade group drive lever that is engaged by a foot 3b and biased to rotate clockwise by a spring 3d;
It has an engaging portion 3c that is engaged and held by the front tensioning lever 4 when charging is completed. 4 locks and holds the leading blade group drive lever 3 that has been fully charged, and at a predetermined timing when releasing the lever, the foot portion 4a is pushed by an actuating member (not shown) and rotates clockwise to release the lock; Leading blade group drive lever 3
A tip tension lever that allows rotation of the tip and activates the tip blade group IO. Reference numeral 5 denotes a rear blade group drive lever that engages with the rear blade group 11 at a foot portion 5a and drives the rear blade group. 6 denotes a rear blade group accumulating lever that receives the force of a spring member 6d and has a biasing force for clockwise rotation. When the charge lever 2 is rotated clockwise, the foot 6a comes into contact with the foot 2b and receives a biasing force for counterclockwise rotation, and the foot 6a contacts the rear blade group drive lever 5 and applies a biasing force to the rear blade group 1.
1, and a protrusion 6c that engages with the rear tensioning lever 9 that locks the biasing force of the spring after charging is completed.
have. Note that the rear blade group drive lever 5 and the rear blade group energy storage lever 6 are biased in the suction direction by a spring 12 (see FIG. 3). Reference numeral 7 designates a double light-shielding lever that rotates and receives force at a gear portion 7b via a gear 8 when the charge lever 2 rotates. It has a gear portion 7b that meshes and receives force. 8 is a gear that meshes with the gear portion 2d of the charge lever 2 and the gear portion 7b of the double light shielding lever 7 to transmit force;
9 engages with the protrusion 6c of the rear blade group storage lever 6 to release the spring 6.
This is a rear tensioning lever that engages the driving force received from the rear blade d, and is rotated clockwise by receiving a force from a rear blade activation member (not shown) on the protrusion 9a to release the lock and activate the travel of the rear blade group 11. do.

In the above configuration, the operation of the shutter will be explained using FIGS. 1 to 5.

FIG. 1 shows a shutter completion state (exposure completion state). That is, the leading blade group drive lever 3 and the trailing blade group drive lever 6 are in the travel completion position, and the shutter base plate 1 is
At this time, the leading blade group 10 is retracted from the aperture 1a and is located below the lower part 10 of the shutter base plate 1, and the rear blade group 11 is stopped by contacting with the notches 1b and lc of the shutter base plate 1. The aperture 1a is located at a position that covers the aperture 1a.

In a camera with a built-in motor drive, charging of the shutter starts immediately after the exposure of the shutter as shown in FIG. 1 is completed.

That is, as shown in FIG. 2, the foot portion 2c of the charge lever 2 receives an urging force by a charging member (not shown) and starts to rotate clockwise. When the charge lever 2 starts rotating clockwise, the foot 2a and the foot 3a of the leading blade group drive lever 3 come into contact, and the leading blade group driving lever 3 starts rotating counterclockwise against the force of the spring 3d. do. Further, the foot portion 6a and the foot portion 2b of the rear blade group accumulating lever 6 come into contact with each other, and the rear blade group accumulating lever 6 starts rotating counterclockwise against the force of the spring 6d. Note that the spring 12 also causes the rear blade group drive lever 5 to follow the rear blade group energy storage lever 6. At this time, the gear portion 2d of the charge lever 2 rotates the gear 8 counterclockwise to rotate the double light shielding lever 7 clockwise from the position shown in FIG. Then, the foot portion 7a of the double shading forming lever 7 comes into contact with the rear blade group drive lever 5 on the way, and from now on, the rear blade group drive lever 5 separates from the rear blade group storage lever 6 against the force of the spring 12. It is pushed by the heavy light shielding lever 7 and starts rotating clockwise. Note that 11a indicates the slit forming end of the rear blade group 11.

FIG. 3 shows the state at the time when the charge lever 2 continues to rotate clockwise and charging is completed.

At this time, the foot portion 3a of the leading blade group drive lever 3 comes into contact with the foot portion 2a of the charge lever 2, and is held at the position shown in FIG. 3 against the force of the spring 3d. The leading blade group 10 engaged with the foot portion 3b is located at a position covering the aperture 1a of the shutter base plate 1 (on the back side of the trailing blade group 11 in FIG. 3).

At this time, the foot portion 6a of the rear blade group energy storage lever 6 also comes into contact with the foot portion 2b of the charge lever 2, and the charging is completed.

At this time, the rear blade group drive lever 5 is pushed by the protrusion 7a of the double shading forming lever 7 rotated by the gear portion 2d of the charge lever 2 and the gear 8, and the rear blade group 11 is moved as shown in FIG. The rear blade group 11 that has been moved to the completion position and engaged with the foot portion 5a is held in a position that covers the aperture 1a of the shutter base plate 1.

That is, in the state shown in FIG. 3, both the leading blade group 10 and the trailing blade group 11 cover the aperture 1a of the shutter base plate 1, and the double light shielding is completed.

Next, the operation of canceling double light shielding before the release operation will be explained.

In the state shown in FIG. 3, when the photographer performs an operation to release double light shielding, for example, performs the first step operation (photometry, distance measurement) of the release button, the charge lever 2 is rotated counterclockwise by the charging member of the camera (not shown). Start (Figure 4). When the charge lever 2 starts rotating counterclockwise, the contact between the foot 2a and the foot 3a of the leading blade group drive lever 3 is released, and the foot 3C of the leading blade group drive lever 3 and the front tensioning lever 4 are brought into contact with each other. As a result, the leading blade group drive lever 3 is prevented from being biased to rotate clockwise by the spring 3d by the leading tensioning lever 4, and maintains the running preparation state.

At this time, the contact between the foot part 2b of the charge lever 2 and the foot part 6a of the rear blade group accumulating lever 6 is released, and the protrusion 6C of the rear blade group accumulating lever 6 and the rear tensioning lever 9 come into contact with each other. The group storage lever 6 is prevented from being urged to rotate clockwise by the spring 6d.

Further, the double light shielding lever 7 rotates counterclockwise in conjunction with the counterclockwise rotation of the charge lever 2, and the rear blade group drive lever 5 that comes into contact with the protrusion 7a follows the lever 7 by the spring 12. The rear blade group power storage lever 6 rotates counterclockwise and moves in a direction where it comes into contact with the rear blade group energy storage lever 6. When the rear blade group drive lever 5 rotates counterclockwise, the foot portion 5a of the rear blade group drive lever 5
The rear blade group 11 engaged with the shutter blade group 11 moves from the position covering the aperture 1a of the shutter base plate 1 toward the upper part 1f of the shutter base plate 1.

As the charge lever 2 further rotates counterclockwise, the 2
The heavy light shielding lever 7 is in the position shown in FIG. At this time, the rear blade group drive lever 5 is released from contact with the double light shielding lever 7, and comes into contact with the leg portion 6b of the rear blade group energy storage lever 6 by the force of the spring 12.

At this time, the rear blade group 11 that has engaged with the leg portion 5a of the rear blade group drive lever 5 is completely retracted from the aperture 1a and is located on the back side of the upper part 1f of the shutter base plate 1.

That is, in the state shown in FIG. 5, the double light shielding is canceled and a state immediately before release is reached in which only the leading blade group 10 covers the aperture 1a.

In the state shown in FIG. 5, when the photographer performs a release operation, for example, a second-stage operation of the release button, the first and second tension levers 4 and 9 are rotated clockwise at predetermined timings by an actuating device (not shown). Then, the protrusion 3c of the leading blade group drive lever 3 disengages from the protrusion 6C of the trailing blade group accumulator lever 6, and the force of the springs 3d and 6d causes the leading blade group drive lever 3 and the trailing blade group accumulator to be released. The levers 6 (while pressing the rear blade group drive lever 5) are rotated clockwise, and the
The rear blade group 10.11 is run to return to the state shown in FIG.

Then, after canceling the double light shielding (Fig. 5), if you stop the release operation (when you try to take a picture but stop doing so, for example, if you change the release button from the first step operation to the second step operation). The following describes the operation when the command is released without performing the above steps.

When the release operation is stopped, the foot 2C of the charge lever 2 is activated by a charge member (not shown) from the state shown in FIG.
is pushed and the charge lever 2 is rotated clockwise. When the charge lever 2 rotates clockwise, the gear 8 engaged with the gear portion 2d rotates counterclockwise, resulting in a double light-shielding lever 7 having a gear portion 7b that meshes with the gear 8.
rotates clockwise. When the double light shielding lever 7 rotates clockwise, the rear blade group drive lever 5 is pushed by the protrusion 7a, and starts rotating clockwise against the force of the spring 12. When the charge lever 2 further rotates clockwise and reaches the charging completion position, it will be in the state shown in FIG. 3, and as already explained, will be in the double light shielding state shown in FIG.

As explained above, this embodiment has a simple structure in which the rear blade group drive lever is essentially two pieces and a double light shielding lever that is linked to the charge lever is added, so that the light is double light shielded when charging is completed. , and in a camera where the double light shielding can be canceled before the release operation, a shutter is provided that can immediately return to the double light shielding state by charging without making the sound of the rear blade group running even if the release operation is canceled. I can,
It has become possible to realize a shutter with no problems in durability since there is no release sound even when photographing is stopped and there is no impact caused by the running of the rear blade group.

〔Effect of the invention〕

The present invention can shorten the release time lag and provide a double light-shielding type camera shutter that takes care of the problems caused by this in advance.

[Brief explanation of drawings]

7...Double light shielding lever 9... Rear tension lever

Claims (1)

[Claims] (1) In a camera shutter having a leading blade group drive lever that drives the leading blade group and a trailing blade group drive lever that drives the trailing blade group, after applying a driving force in the shutter traveling direction to the trailing blade group drive lever. a blade group biasing member; a charging member that charges the rear blade group biasing member from a shutter travel complete position to a travel preparation position; For a camera, comprising a double light-shielding drive mechanism that moves a rear blade group drive lever in the shutter travel direction and moves the rear blade group drive lever from a charge release position to a shutter travel preparation position. Shutter.