JPH05273643A - Vibrationproofing device for camera - Google Patents

Abstract

PURPOSE:To prevent vibration by a small space and small driving energy by allowing a balance weight to have inertial mass larger than that of a reflecting mirror and to be moved in a shorter distance than the reflecting mirror. CONSTITUTION:The balance weight 107 is constituted so as to be positioned op the back surface of the reflecting mirror 101 when the mirror 101 is set at a position where the image of an object can be observed from a finder. Then, the mass of the weight 107 has a larger value than the mass obtained by summing up the mirror 101 and the supporting frame 102 thereof. Besides, a groove cam 106a provided on the frame 106 and pins 108a and 108b are arranged and shaped so that the moving distance of the weight 107 on a circular- arc becomes shorter than the moving distance of the mirror 101 and the frame 102 on a circular-arc plotted by the composite center of gravity G3. Therefore, the weight 107 having the larger mass than the mirror 101 and the frame 102 is moved in a reverse direction to the mirror 101 in the shorter distance than the center of gravity G3. Thus, the vibration generated from the reflecting mirror in the inside of a camera can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation device for a camera.

[0002]

2. Description of the Related Art Conventional devices of this type include, for example, Jitsuko Sho 5
There is one that prevents camera shake by absorbing the vibration generated with the rotation of the reflecting mirror, such as "No. 3-7058""camera shake prevention device by rotating mirror of single-lens reflex camera".

This device is provided with a lever that rotates in the opposite direction of the reflecting mirror in conjunction with the rotation of the reflecting mirror, and the counterweight is fixed to the tip of the lever so that the counterweight moves. The structure is such that it absorbs the vibration that accompanies the rotation of the reflecting mirror.

[0004]

In such a conventional device, no consideration is given to the relationship between the mass of the counterweight, its moving distance and the moving distance of the center of gravity of the reflecting mirror. This resulted in the following drawbacks. That is, in the conventional device, the counterweight moves a considerably long distance as compared with the center of gravity of the reflecting mirror. A wide space for moving the weight is required inside the camera, and when such a conventional device is incorporated in a camera with a large volume limitation, the camera itself has a drawback of being upsized.

Further, the driving energy required to move the counterweight is inevitably large because the moving distance of the weight is long, and in the case of the conventional device, it is about the same as or more than the driving energy of the reflecting mirror alone. Energy was needed for the counterweight. Therefore, when such a counterweight is built into the camera, a large amount of drive energy is required as compared with the case where the counterweight is not provided, and the force required to wind the camera is equal to the drive energy. There was a serious drawback that it was inevitably large to charge. This appears as a drawback such as a reduction in frame speed and a reduction in battery life in the cameras of recent years in which the motor drive device is often used by being mounted. The present invention is to solve the drawbacks of the conventional device, in which a counterweight having a mass larger than the mass of the reflecting mirror is provided in the opposite direction to the reflecting mirror. It is an object of the present invention to obtain a camera anti-vibration device capable of performing anti-vibration with a small space and a small drive energy by simultaneously moving a shorter distance.

[0006]

That is, in the conventional apparatus, the vibration generated by the operation of the reflecting mirror is canceled by the momentum possessed by the counterweight moving in the opposite direction to the reflecting mirror. , Had the anti-vibration effect. Here, the momentum possessed by the counterweight is represented by the product of the mass of the counterweight and the motion velocity of the counterweight. Therefore, in order to obtain the same vibration damping effect as that of the conventional device, it is sufficient to operate the counterweight having the momentum equal to the momentum of the counterweight of the conventional device. Specifically, even if a counterweight having a larger mass than the conventional device is moved at a slower speed than the conventional device, the value of the product of the mass and the speed should be the same as that of the conventional device. For example, the vibration isolation result is equivalent to that of the conventional device.

On the other hand, the energy required to drive the above-mentioned counterweight is proportional to the mass of the counterweight and proportional to the square of the motion velocity. Therefore, when the above-mentioned energy is expressed by using the value of the momentum, the energy becomes "proportionally proportional to the momentum of the counterweight and further proportional to the motion speed of the counterweight." Therefore, when a counterweight having a momentum equivalent to that of the conventional device is moved at a slower speed than the conventional device, the energy required to drive the counterweight is reduced by the decrease in the motion speed. You can see that Further, in this case, the momentum possessed by the counterweight is equal to that of the conventional apparatus, and thus it is clear that the antivibration effect of the counterweight is equal to that of the conventional apparatus. From the above, when a counterweight having a larger mass than the conventional device is moved at a slower speed than the conventional device, as long as the momentum is equivalent, it has the same vibration isolation effect as the conventional device. Moreover, it is possible to obtain a vibration damping device that requires less drive energy. Here, the counterweight starts moving at the same time as the reflecting mirror and stops at the same time. Therefore, the moving distance of the counterweight may be short because the moving speed is slow.

[0008]

According to the present invention, the driving energy of the counterweight is not larger than that of the reflecting mirror, the mass of the counterweight is larger than that of the reflecting mirror, and the counterweight is the same. I tried to make the moving distance shorter than that of the reflector.

As described above, according to the present invention, by moving the counterweight having a mass larger than that of the reflecting mirror by a distance shorter than that of the reflecting mirror, a highly efficient vibration damping device capable of operating with less energy is provided. Obtainable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, which is applied to an anti-vibration device for a reflecting mirror of a single-lens reflex camera.

In FIG. 1, reference numeral 101 is a reflecting mirror of a single-lens reflex camera. Reference numeral 102 is a support frame for holding the reflecting mirror, and the supporting frame 102 is attached to the reflecting mirror 101 by a known method. The combined center of gravity of the reflecting mirror 101 and the support frame 102 is at the position shown in FIG. 1G3. 1
Reference numerals 03a and 103b are pins that are planted laterally of the support frame 102, and are fitted into the holes of the bearings 104a and 104b provided on the camera body, respectively. With the above configuration, the reflecting mirror 101
Around the axis passing through pins 103a and 103b,
It is rotatably held and can be reciprocally rotated by a known driving device (not shown) between a descending position where the subject image can be observed through the finder and an ascending position retracted outside the photographing light beam. .. Further, 105 is a support frame 10
It is an interlocking pin planted on the side of 2.

Reference numeral 106 denotes a counterweight support frame, in which a cam groove 106a is provided in the arm portion, a pin 105 planted on the support frame 102 is inserted, and one end is provided with a fishing line. The compound weight 107 is attached by means not shown. Again 10
Reference numerals 8a and 108b denote pins implanted in the side surfaces of the counterweight support frame 106, respectively, which are fitted in the holes of the bearing portions 109a and 109b provided in the camera body,
The support frame 106 is rotatably supported around an axis passing through the pins 108a and 108b. With the above configuration, when the reflecting mirror 101 rotates clockwise about the axis passing through the pins 103a and 103b, the counterweight support frame 106 and the counterweight 107 are guided by the pin 105, and the pin 1
It is designed to rotate counterclockwise around an axis passing through 08a and 108b. On the contrary, when the reflecting mirror 101 rotates counterclockwise, the counterweight support frame 106 and the fishing rod are rotated. The compound weight 107 is adapted to rotate clockwise. From the above, the center of gravity G3 of the reflecting mirror 101 and the counterweight 107
Are always moving in opposite directions.

Here, in the present embodiment, the counterweight 107
Is configured to take the position shown in the rear view of the reflecting mirror 101 when the reflecting mirror 101 is in a position where the subject image can be observed from the viewfinder. The mass of the counterweight 107 has a larger value than the total mass of the reflecting mirror 101 and its supporting frame 102. Further, regarding the arrangement and shape of the groove cam 106a provided on the counterweight support frame 106 and the pins 108a and 108b, the movement distance on the arc of the counterweight 107 that rotates in an arc is determined by the reflection mirror 101 and the support frame 102. It is configured to be shorter than the movement distance on the arc drawn by the combined center of gravity G3. Therefore, the counterweight 107, which has a larger mass than the reflector 101 and the reflector support frame 102, moves in a direction shorter than the center of gravity G3 in the direction opposite to the reflector.

2A and 2B show a state in which this embodiment is incorporated in an actual single-lens reflex camera. 2a
In b and b, 110 is a taking lens, 111 is a finder, 112 is a shutter, and 113 is a film surface. In the above embodiment, the counterweight 107 is mounted on the counterweight support frame 106. The counterweight is made of synthetic resin, and the counterweight is made of metal such as lead having a large specific gravity. Needless to say, it is okay to embed.

The above is the configuration of the present embodiment. Next, the operation will be described with reference to FIGS.

FIG. 2a shows that the reflecting mirror has a viewfinder 111.
2b shows a state in which a so-called descending position where the subject image can be observed is taken, and FIG. 2b shows a state in which the reflecting mirror has taken a so-called ascending position where the reflecting mirror is retracted from the photographing optical path. Therefore, in FIG. 2a, when a release button of a camera (not shown) is pressed down, a reflector driving device (not shown) is activated, and the reflector 101 and the support frame 102 move from the illustrated lowered position to the raised position. The clockwise rotation is started around the pin 103a. Along with this, counterweight 107
In the cam groove 106a provided in the support frame 106
Pin 105 on 02 is plugged in, so pin 1
Rotation starts in the counterclockwise direction around 08a and 108b. At this time, the moving speed of the counterweight 107 is slower than the moving speed of the center of gravity G3 of the reflecting mirror 101 and the supporting frame 102, but the mass of the counterweight 107 is the reflecting mirror 101 and the supporting frame 1.
Since it is larger than the total mass of No. 02, it cancels out the vibrations that accompany the movement of the reflecting mirror, thus isolating the camera body.

The clockwise rotation around the pin 103a of the reflecting mirror 101 further progresses, and the reflecting mirror 101 is moved to the position shown in FIG.
When the movement is stopped by moving to the raised position as shown in FIG.
6, the counterweight 107, which was moving in conjunction with the reflecting mirror 101, also stops moving. At this time, an impact force is generated by stopping the reflecting mirror 101 and its supporting frame 102, but by simultaneously stopping the counterweight 107 which has a mass larger than that of the reflecting mirror 101 and the supporting frame 102 and is moving at a slow speed. The opposite impact force is generated from the above impact force. Therefore, these two impact forces cancel each other out to reduce the impact force that propagates to the camera body, thus isolating the camera.

After that, the exposure of the film surface 113 by the shutter 112 is completed, and the reflecting mirror 101 returns from the raised position to the lowered position. In this case as well, the movement of the counterweight 107 causes Impact vibration due to the movement of the reflecting mirror 101 and the support frame 102 is canceled to prevent the camera from vibrating.

In the above-mentioned embodiment, by properly selecting the mass of the counterweight and its movement distance, it is possible to obtain an antivibration device capable of almost completely canceling the shock and vibration caused by the movement of the reflecting mirror. It goes without saying that it is possible.

In the above embodiment, the moving distance of the counterweight may be shorter than the moving distance of the center of gravity of the reflecting mirror and the supporting frame of the reflecting mirror, so that the balancing weight can be arranged on the back surface of the reflecting mirror. Since it can be moved, there is an advantage that the space inside the camera can be effectively utilized. Further, in the conventional camera, stray light that passes through the taking lens 110, passes through the gap at the lower end of the reflecting mirror and reaches the shutter surface 112 enters the film surface through the gap of the light shielding member of the shutter, and the film is exposed. There was a frequent light leakage accident. Therefore, if the counterweight is arranged on the back surface of the reflecting mirror as in the present embodiment, the counterweight can be utilized as a light blocking member for blocking the stray light as described above. There is also an advantage that accidents can be prevented.

[0021]

As described above, according to the present invention, the vibration generated from the reflecting mirror inside the camera is effectively dampened by using the counterweight. Therefore, at the time of photographing, the camera shake caused by the vibration is caused. There is an advantage that the vibration damping device can be obtained without increasing the size.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2A is a sectional view of a camera incorporating an embodiment of the present invention. (B) It is sectional drawing of the camera incorporating the Example of this invention.

[Explanation of symbols]

 101 Reflector 102 Reflector support frame 107 Counterweight

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[Procedure amendment]

[Submission date] January 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Here, in the present embodiment, the counterweight 107
Is configured to take the position shown in the rear view of the reflecting mirror 101 when the reflecting mirror 101 is in a position where the subject image can be observed from the viewfinder. The mass of the counterweight 107 has a larger value than the total mass of the reflecting mirror 101 and its supporting frame 102. Further, regarding the arrangement and shape of the groove cam 106a provided on the counterweight support frame 106 and the pins 108a and 108b, the movement distance on the arc of the counterweight 107 that rotates in an arc is determined by the reflection mirror 101 and the support frame 102. It is configured to be shorter than the movement distance on the arc drawn by the combined center of gravity G3. Therefore, the counterweight 107 having a mass larger than the sum of the masses of the reflecting mirror 101 and the reflecting mirror supporting frame 102 moves in a direction shorter than the center of gravity G3 in the direction opposite to the reflecting mirror.

Claims (4)

[Claims] 1. A vibration-damping device for a camera, comprising: a counterweight that is activated and stopped substantially at the same time as the reflector in a direction opposite to that of the reflector that retracts out of the optical path during photography. Is a camera having a larger inertial mass than the reflecting mirror, and moves a shorter distance than the reflecting mirror. 2. A motion activation member for activating the movements of the reflecting mirror and the counterweight at substantially the same time; and a stop member arranged to stop the movements of the reflector and the counterweight at substantially the same time. The image stabilizing device for a camera according to claim 1, wherein the image stabilizing device is a camera. 3. The light blocking member for blocking stray light which passes through the photographing lens, passes through the gap at the lower end of the reflecting mirror and reaches the shutter surface, and also serves as a counterweight. Anti-vibration device for camera. 4. A reflecting mirror and a counterweight are connected to each other, and the movement of the reflector is reversed to transmit the motion to the counterweight, and the movement speed of the reflector is decelerated so as to perform the fishing. 2. A transmission member for transmitting to the weight is provided.
Anti-vibration device for the camera described.