JPS62166324A - Vibration-proof device for single lens reflex camera - Google Patents

Abstract

PURPOSE:To effectively suppress vibrations that can not be ignored which are caused by a subordinate reflecting mirror and to eliminate camera shake by providing a main balance weight which suppresses a camera shake caused principally by a main reflecting mirror and a subordinate balance weight which suppresses a camera shake caused principally by the subordinate reflecting mirror. CONSTITUTION:When the main balance weight 12 rotates counterclockwise, a shaft 16 which supports the subordinate balance weight 13 rotatably rotates counterclockwise around a pin shaft 11 together with the main balance weight 12. The bent part 13B of the subordinate balance weight 13 which engages a fixed pin 17 through an engagement groove 13C by the rotation of the shaft 16 revolves counterclockwise around the pin shaft 11 and also is rotated and displayed counterclockwise around the shaft 16 at the same time. The whole subordinate balance weight 13 is rotated and displayed counterclockwise around the shaft along with the bent part 13B. Then, when the main balance weight 12 moves to a lower position, the subordinate balance weight 13 reaches a shelter position parallel to the top surface of the main balance weight 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an anti-vibration device for preventing camera vibrations that occur as a reaction to the rotation of a rapidly swinging reflector in a two-eye reflex camera.

[Technical field of invention]

Conventionally, in single-lens reflex cameras that have a movable reflector that swings optimally between the viewfinder observation position on the photographic optical path and a retracted position outside the photographic optical path, the camera body However, the variable reflector was displaced and vibrated in the opposite direction to the movement of the variable reflector, causing camera shake. Therefore, a balance weight that balances the movement of the movable reflector is installed in a narrow space between the movable reflector at the observation position and the film aperture, and a material with a high specific gravity is used for the balance weight. A vibration isolating device for a single-lens reflex camera configured to prevent camera shake by moving the mirror along the bottom wall of the mirror chamber is disclosed, for example, in Japanese Patent Application Laid-Open No. 58-66922, and is already well known.

On the other hand, in recent years, exposure control or autofocus (hereinafter referred to as r)
It is called AFj. ) is placed at the bottom of the mirror chamber below the movable reflector, and a sub-reflector installed behind the main reflector for viewfinder observation guides the light from the photographic lens to the light-receiver. TT configured in
L-type single-lens reflex cameras are becoming more and more popular. In this camera, the above-mentioned sub-reflector maintains an opening angle of approximately 900 degrees with respect to the main reflector when the main reflector is in the viewfinder observation position, and when the main reflector rotates to the retracted position, It is configured to be retracted out of the photographing optical path together with the main reflecting mirror and to come into close contact with the back surface of the main reflecting mirror. Therefore, while the main reflector rotates approximately 45 degrees, the sub-reflector operates at a rotation angle approximately three times that of the main reflector, and the rotational angular acceleration of the sub-reflector is approximately three times that of the main reflector. Become. Therefore, even if the mass of the sub-reflector is reduced to about 173 to 1/4 of that of the main mirror, the vibration of the camera generated by the sub-reflector will be 1/2 to 1/4 compared to the vibration caused by the main reflector. It is of the same magnitude and cannot be ignored.

By the way, when vibrations are prevented using a balance weight that is linked to the rotation of the main reflector as in the conventionally known technology for a single-lens reflex camera having such a sub-reflector, vibrations due to the rotation of the main reflector are prevented. However, in order to reduce camera shake caused by the rotation of the sub-reflector, a balance weight with extremely large specific gravity and volume is required, and this is placed at the bottom of the narrow mirror chamber. It is difficult to set up. Therefore, it is conceivable to add another balance weight that is linked to the sub-reflector in addition to the balance weight that is linked to the main reflector, but it is also possible to install a similar anti-shake mechanism twice inside the camera, which has many spatial limitations. Providing such a camera has the drawback of increasing the size of the camera and complicating the mechanism, especially the interlocking mechanism between the reflecting mirror and the balance weight.

[Purpose of the invention]

The present invention solves the drawbacks of the above-mentioned conventional devices, and has an anti-vibration system for single-lens reflex cameras that can extremely effectively prevent vibrations caused by the main reflecting mirror and the sub-reflecting mirror without increasing the size of the camera. The purpose is to provide equipment.

[Summary of the invention]

In order to suppress the camera shake that occurs as a reaction to the rising of the reflecting mirror, a pan lance weight with momentum that is balanced by the vertical component of the momentum that the reflecting mirror has while rising is displaced in the opposite direction to that of the reflecting mirror. Just say no. Since the kinematics is the product of the mass of the object and the speed of the center of gravity, vibration can be effectively suppressed by using balance weights with different speeds for two reflecting mirrors with significantly different speeds. Therefore, in order to achieve the above object, the present invention has a main reflecting mirror that is movable from an observation position on the photographing optical path to a retracted position outside the photographing optical path in conjunction with a movement mechanism.
A main balance weight that is displaced in the opposite direction to the main reflector and maintains dynamic balance with the main reflector, and a light receiving element that is installed on the photographing optical path behind the main reflector and receives light from the photographic lens. A sub-reflector that guides the movement is provided with a sub-balance weight that is interlocked with the main balance weight so as to be displaced in the direction of movement, and that maintains a dynamic balance with the sub-reflector. The technical point is to configure the camera to suppress camera shake caused by camera shake.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an embodiment of the present invention, and FIGS.
The figure is a vertical sectional view of a camera incorporating the embodiment shown in Figure 1, Figure 2 shows the state when the reflector is in the observation position, and Figure 3 shows the state when the reflector is raised to the retracted position. shows.

? In Figure 2, part of the light that passes through the photographic lens is
Main reflection &ii M with semi-transparent part in the center.

The light is reflected by the light beam, reaches the lower surface of the condenser lens L2 which also serves as a focus plate, and a subject image is formed there.

The image is created using a well-known pentaprism P and an eyepiece L.
Observed throughout 3. In addition, some of the other light that passes through the semi-transmissive part of the main reflecting mirror M1 and goes towards the film F is reflected downward by the sub-reflecting mirror M2, and is provided on the main balance weight 12, which will be described in detail later. The light is received by a light receiving element P fixed in a bottom chamber IB provided between the mirror chamber bottom wall 1a and the camera bottom wall 1b of the camera body 1 through the transparent window 12A. This bottom chamber IB accommodates gears, electric circuits, etc. that are interlocked with a known winding lever.

Further, as shown in FIG.
It is configured to rotate counterclockwise in the figure to a position parallel to the main reflecting mirror Ml and retreat out of the photographing optical path. In addition, a shutter S is provided on the front surface of the film F, and two sets of blades move vertically to open and close the film opening.

In FIG. 1, the main reflecting mirror M1 is housed in a mirror chamber IA indicated by a two-dot chain line, and is held by a main reflecting mirror holding frame 2. As shown in FIG. This main reflecting mirror holding frame 2 is rotatably supported by pin shafts 3 installed on both side walls of the mirror chamber IA provided with light shielding lines.

Main reflecting mirror supporting arms 4 are fixedly provided on both side surfaces of the main reflecting mirror holding frame 2, respectively, and a driving pin 5 is fixedly provided through one end of the main reflecting mirror supporting arm 4.

Further, the sub-reflector M2 is fixed to a protruding arm 6B of the sub-reflector support plate 6 which is rotatably supported by the drive pin 5.

An arm 6A extending upwardly is provided on the left side of the sub-reflector support plate 6 in FIG. are loosely engaged. The cam groove 6C rotates the sub-reflector support plate 6 around the drive pin 5 when the main reflector vJ,M rises to the retracted position together with the drive pin 5, and moves the sub-reflector M2 to the position shown in FIG. As shown in the figure, it is configured to be retracted out of the photographing optical path. The sub-reflector support plate 6 also supports the main reflector M.
.

comes into contact with the fixing pin 9 installed in the camera body 1, and the first
When it is in the observation position as shown in the figure, it is urged to rotate clockwise by the clip spring 8 and comes into contact with the restriction pin IO, thereby holding the sub-reflector M2 at a predetermined angle with respect to the photographing optical axis. It is structured as follows.

The clip spring 8 has one end engaged with a pin 4A on the main reflector support arm 4 and the other end engaged with a pin 6D on the sub-reflector support plate 6, and is directed in a direction that brings both pins 4A and 6D closer to each other. is energized. The relative positions of these pins 4A and 6D are such that when the main reflector M is in the observation position, the clip spring 8 biases the sub-reflector support plate 6 to rotate clockwise around the drive pin 5. However, when the main reflector M1 and the sub-reflector M2 are retracted out of the photographing optical path, the sub-reflector support plate 6 is urged to rotate counterclockwise around the drive pin 5, and the sub-reflector It is selected to apply a force to the clip spring 8 that brings M2 into close contact with the main reflecting mirror M1. That is, the clip spring 8 and the sub-reflector support plate 6 are the main reflector M.

A so-called toggle mechanism in which the direction of the biasing torque is reversed for the sub-reflector M2 rotating around the drive pin 5 depending on whether it is in the observation position or in the retracted position outside the photographing optical path. It consists of

On the other hand, a main balance weight 12 rotatably supported by a pin shaft 11 is provided at the bottom of the mirror chamber IA, and a sub-balance weight 13 is rotatably provided on the main balance weight 12. The main balance weight 12 includes an interlocking lever 15A that engages with the drive pin 5 and is supported by the fixed shaft 14;
The main reflecting mirror M is connected to this via the connecting lever 15B.
, the mirror chamber bottom wall 1 shown in FIGS. 1 and 2
From the raised position inclined with respect to a to the retracted position where the top surface is aligned with the bottom wall 1a of the mirror chamber as shown in Fig. 3, it is approximately 15 degrees.
(approximately 1/3 of the rotation angle of the main reflecting mirror M). The main balance weight 12 is formed into a box shape with a width equal to the horizontal width of the mirror chamber IA (the length in the left-right direction in FIG. As shown in FIG. 4, a window hole 12A for guiding light to the light-receiving element l) in the light-receiving element l) is provided approximately in the center. Inside the main balance weight 12, as shown in FIG. 5, two weight blocks 12B of high specific gravity such as tungsten alloy are provided with a window hole 12A in between, and each weight block 12B is as shown in FIG. Pressing spring 12
It is fixed to the back side by C. Thereby, the main balance weight 12 includes the main reflection mirror MI and the support member 2 that supports it.
．． 4 and drive pin 5.

The secondary balance weight 13 consists of a flat part 13A that covers the upper surface of the main balance weight 12, and a bent part 13B supported by shafts 16 implanted on both side surfaces of the main balance weight 12. The bent portion 13B is provided with an engagement groove 13C that loosely engages with the fixing pin 17. Further, the secondary balance weight 13 is biased by a clip spring 18 coupled to a pin 19 implanted on the side surface of the main balance weight 12, and when the main balance weight 12 is in the inclined raised position,
Due to the biasing force of the clip spring 18, the clip rotates clockwise around the shaft 16 and comes into contact with the restriction pin 20, and is placed in the greatly inclined open position as shown in FIG. However, when the main balance weight 12 descends to the retracted position as shown in FIG. It is configured.

Here, when the main balance weight 12 is in the inclined raised position, the clip spring 18 moves the sub balance weight 13 to the axis 1.
6, and when the main balance weight 12 is in the lowered position as shown in FIG. 3, the secondary balance weight 13 is rotated counterclockwise around the shaft 16. The positions 13a and pin 19 of the spring hooks on the shaft 16 at both ends are determined so as to bias the main balance weight 12 so as to bring it into close contact with the upper surface of the main balance weight 12.

The bent portion 1 supported by the clip spring 18 and the shaft 16
3B, as in the case of the clip spring 8 described above,
A toggle mechanism is configured. Note that, as shown in FIG. 3, when the sub-balance weight 13 comes into close contact with the upper surface of the main balance weight 12, it forms a part of the bottom wall of the mirror chamber. Further, the upper surface of the sub-balance weight 13 is provided with a light-shielding line, similar to the upper surface of the main balance weight 12 and the wall surface of the mirror chamber.

Further, the sub-balance weight 13 is formed to be dynamically balanced with the sub-reflector M2. In this case, the opening angle of the sub-balance weight 13 with respect to the main balance weight 12 is as small as approximately 1/3 of the opening angle (approximately 90°) of the sub-reflecting mirror M2 with respect to the main reflecting mirror M. However, since the sub-reflector support plate 6 is made of aluminum alloy or titanium alloy and is small and lightweight,
The sub-balance column stud 13 can be made of a plate material such as copper or copper alloy (brass). If there is insufficient mass,
A material having a high specific gravity such as a tungsten alloy may be fixed to a position on the back surface of the main balance weight 12 facing the window hole 12.

On the other hand, the drive pin 5 that swings together with the main reflecting mirror M1 is urged downward in FIG. It can be engaged with one arm 23B of the reflector lifting lever 23 that is supported. In addition, the reflector raising lever 23
The counterclockwise rotation of is prevented by the restriction pin 24. The other arm 23A of the reflector lifting lever 23 is provided with a bent portion 23a, and further has two pins 25 and 26 implanted therein.

The fixed shaft 22 supporting the reflector raising lever 23 has a first
A reflector lowering lever 28, which is always urged counterclockwise by a charge spring 27, is rotatably supported. The tip 28 of one arm 28A of this reflector lowering lever 28
a is configured to be able to be engaged with the bent portion 23a of the reflector lifting lever 23. Also, on one arm 28A, 2
The main pins 29 and 30 are implanted, and one pin 29 is the second
It is connected to one pin 25 of the reflector lifting lever 23 via a charge spring 31.

The other pin 26 implanted at the tip of the arm 23A of the reflector lifting lever 23 is a first hook member that is rotatably supported by the fixed shaft 32A and biased counterclockwise by a tension coil spring 33. 34. The other pin 30 implanted at the tip of the arm 28A of the reflector lowering lever 28 is a second hook member rotatably supported by a fixed shaft 32B and biased clockwise by a tension coil spring 35. 36.

Further, the rotation of the first hook member 34 and the second hook member 36 by the biasing force of the tension coil spring 33.35 is restricted by a restriction pin 37.38, respectively.

Further, inclined surfaces 34a and 36a are provided at the ends of the first hook member 34 and the second hook member 36, respectively, and when the pin 26 climbs over the inclined surface 34a, the reflector lifting lever 23 is moved by the first hook member 34. The rotation in the direction is restricted, and the pin 30
When the mirror gets over the slope 36a, the reflector lowering lever 28
is restrained from rotating counterclockwise by the second hook member 36.

Note that, as shown in FIG. 2, a packing 39 made of an elastic member is provided on the back surface of the bottom wall 1a of the mirror chamber IA. As shown in FIG. 3, the tip of this gasket 39 is in constant contact with the balance weight 12 to close the gap between the bottom wall la and the balance weight 12, and from this part into the camera bottom chamber IB. It is configured to prevent dirt, etc. from entering.

Further, the reflector lowering lever 28 rotates clockwise in conjunction with the winding operation of the winding lever 40 provided at the top of the camera body 1, and charges the first charge spring 27 and the second charge spring 31 at the same time. It is configured as follows.

Further, the first hook member 34 is configured to rotate clockwise to release the pin 26 by pressing the release button 41, and the second hook member 36 is configured to release the pin 30 in conjunction with the shutter S. has been done.

The tension coil spring 21 is designed to have a biasing force that is weaker than the biasing force of the second charge spring 31 and stronger than the resultant force of the two clip springs 8 and 18 when the main reflecting mirror M1 is outside the photographing optical path. Also, one clip spring 1
8 is configured to have a biasing force greater than the weight of the secondary balance weight 13 when the main balance weight 12 is in the raised position. Furthermore, the first charge spring 27 that biases the reflector lowering lever 28 is configured to have a stronger biasing force than the tension coil spring 33 that biases the first hook member 34.

Next, the operation of the above embodiment will be explained.

FIG. 1 shows a state in which the winding lever 40 of the camera is wound up, the first charge spring 27 and the second charge spring 31 are charged, and preparation for photographing is completed.

In the photographing ready state, the pin 26 of the reflector raising lever 23 is locked by the first hook member 34, and the pin 30 of the reflector lowering lever 28 is locked by the second hook member 36, as shown in FIG. As shown, the tip 28a of one arm 28A of the reflector lowering lever 28 is connected to the reflector raising lever 23.
It is placed spaced apart from the bent portion 23a. Also, reflector M.

is placed at the observation position on the photographic optical path. In this case, the reflection v
Since LM is biased downward in FIG. 1 by the tension coil spring 21 via the drive pin 5, it is placed at the observation position determined by the fixing pin 9 and can be freely displaced counterclockwise. There is no. Furthermore, the sub-reflector support plate 6 biased clockwise by the clip spring 8
As a result, the sub-reflection vLM z is held tilted at a predetermined angle with respect to the photographing optical axis, and the photographing lens L
1, and further transmitted through the central portion of the main reflecting mirror M, is directed toward the light receiving element P. Further, the main balance weight 12, which is interlocked with the main reflecting mirror M1 via the interlocking lever 15A and the connection lever 15B, is placed in a raised position inclined to the bottom wall 1a of the mirror chamber, and the sub-balance weight 13 is placed in the limit bin 2.
It is placed in the open position abutting zero. In this state, the second
As shown in the figure, the sub-balance weight 13 is located on the back side of the main reflecting mirror M1, passes through the photographing lens L1, and passes through the main reflecting mirror M1.
Since the light directed toward the shutter S is directed from the lower side of the shutter S, the fear of light leakage from the joints of the blades of the shutter S can be eliminated.

When the above-mentioned photographing 411u is completed, when the release 41 (see Fig. 1) is pressed down, the 1st!4th member 3
4 is recessed clockwise against the biasing force of the tension coil spring 33 to release the pin 26 and release the reflector lifting lever 23. When the reflector lift lever 23 is released, the reflector lift lever 23 rotates clockwise due to the biasing force of the second charge spring 31, and one arm 23B comes into contact with the drive bin 5, causing the drive bin 5 to move. Tension coil spring 21
The pin is rotated counterclockwise around the pin shaft 3 against the urging force of the pin.

Due to this counterclockwise rotational movement of the drive pin 5, the main reflecting mirror M1 rises from the observation position shown in FIG. 2 to the retracted position shown in FIG. 3, and then stops. Also, as the main reflecting mirror M rises, the sub-reflecting mirror support plate 6 supported by the drive pin 5
The cam groove 6C that engages with the fixed pin 7 rotates around the drive pin 5 while sliding with respect to the fixed pin 7.

Therefore, the sub-reflector support plate 6 rotates counterclockwise about the drive pin 5 while rising together with the drive pin 5.

Due to this rotational displacement of the sub-reflector support plate 6, the sub-reflector M2
, further rotates counterclockwise while rising together with the main reflecting mirror M, and comes into close contact with the back surface of the main reflecting mirror M, and as shown in FIG. Main reflector M.

The semi-transparent part of the central part of the light is blocked.

On the other hand, when the drive pin 5 is moved from the position shown in FIG.
At the same time, when the pin shaft 3 rotates counterclockwise around the pin shaft 3, the interlocking lever 15A that engages with the drive pin 5 rotates counterclockwise around the fixed shaft 14.

This rotation of the interlocking lever 15A is transmitted to the main balance weight 12 via the connection lever 15B, and the main balance weight 12 rotates clockwise about the pin shaft 11. In this case, when the main reflecting mirror M1 is deviated by about 456 rotations from the observation position shown in FIG. 2 to the retracted position shown in FIG. 3, the main balance weight 12 is lowered from the raised position shown in FIG. approximately 156 rotations to the position. Therefore, the rotational angular velocity of the main balance weight 12 is approximately ⅓ of that of the main reflecting mirror M. However, by increasing the mass of the main balance weight 12 with the block weight 12B, the dynamic balance between the main reflection mirror M1 and the main balance weight 12 is maintained, and the vibration of the camera due to the rotation of the main reflection mirror M is reduced. , is canceled by this rotational deflection of the main balance weight 12 in the opposite direction.

When the main balance weight 12 rotates counterclockwise, the shaft 16 that rotatably supports the sub balance weight 13 rotates counterclockwise around the pin shaft 11 together with the main balance weight 12. By this rotation of the shaft 16, the bent portion 13B of the sub-balance weight 13 engages with the fixed bottle 17 via the engagement groove 13c.
revolves counterclockwise around the pin shaft 11 and at the same time rotates counterclockwise about the shaft 16. The entire sub-balance weight 13 together with the bent portion 13B is rotated counterclockwise about the shaft 16. As a result, when the main balance weight 12 moves to the lowered position shown in FIG. 3, the sub balance weight 13 reaches a retracted position parallel to the upper surface of the main balance weight 12.

When the sub-reflecting mirror M2 is retracted upwardly out of the photographing optical path as described above, the sub-balance weight 13 is simultaneously retracted downwardly outside the photographing optical path. At this time, the rotation angle of the sub-balance weight 13 is approximately 1/3 of the rotation angle of the sub-reflector M2, and the rotation angular velocity of the sub-balance weight 13 is considerably slower than the rotation angular velocity of the sub-reflector viM2. However, by making the mass of the sub-balance weight sufficiently larger than that of the sub-reflector M2, a dynamic balance between the two can be maintained. Therefore, the vibration of the camera caused by the retracting operation of the sub-reflector M2 out of the photographing optical path can be eliminated by the retracting operation of the sub-balance weight 13.

When the main reflecting mirror M and the sub-reflecting mirror M2, together with the main balance weight 12 and the sub-balance weight 13, are retracted out of the photographing optical path, the shutter S is activated by the completion signal of the upper limit of the main reflection mirror M1, and exposure is performed. . When this series of exposure operations is performed, the exposure completion signal is transmitted to the second hook member 36 that has received the exposure completion signal.

Upon receiving the exposure end signal, the second hook member 36 rotates counterclockwise against the biasing force of the tension coil spring 35 to release the bin 30 and release the reflector lowering lever 28. The released reflector lowering lever 28 is rotated counterclockwise around the fixed shaft 22 by the biasing force of the first charge spring 27.
Bent portion 23a facing the tip 28a of one arm 28A
, the reflector lift lever 23 is rotated counterclockwise around the fixed shaft 22, and one arm 23B comes into contact with the restriction bin 24, thereby moving the reflector lowering lever 28 and the reflector raising lever 23. stop together. In the meantime, the first hook member 3
4 is lifted clockwise against the biasing force of the tension coil spring 33 and is locked to the hook portion of the first hook member 1.

Further, the drive pin 5 that engages with one arm 23B of the reflector lift lever 23 moves the pin shaft 3 by the biasing force of the tension coil spring 21, following the rotation of the reflector lift lever 23 in the counterclockwise direction. The main reflecting mirror M is moved from the retracted position shown in FIG. 3 to the observation position shown in FIG. 2 by moving the main reflecting mirror M upward in a clockwise direction. At the same time, the sub-reflector support plate 6 is lowered via the cam groove 6C that engages with the fixed pin 7, and rotated clockwise around the drive pin 5.
The sub-reflector M2 is returned to a predetermined position on the I-most shadow optical path. In this case, the main reflector M1 is pressed by the tension coil spring 21 so as to come into contact with the fixing pin 9, and the sub-reflector M2 is
The biasing force of the clip spring 8 presses the sub-reflector support plate 6 against the restriction pin 10 and holds it in a predetermined position. As a result, a part of the luminous flux that has passed through the photographic lens L is reflected upward in FIG. 2 by the main reflecting mirror M1,
The object image can be observed through the finder eyepiece. Further, a part of the light beam transmitted through the main reflecting mirror M1 is reflected downward by the sub-reflecting mirror M2, and is received by the light receiving element P.

On the other hand, when the drive pin 5 rotates clockwise together with the main reflector M1 due to the biasing force of the tension coil spring 21 following the counterclockwise rotation of the reflector raising lever 23, the interlocking lever 1
5A rotates clockwise around the fixed shaft 14, and rotates the main balance weight 12 clockwise around the pin shaft 11 via the connecting lever 15B. Due to this clockwise rotation, the main balance weight 12 is rotationally displaced from the lowered position shown in FIG. 3 to the raised position shown in FIG. It rotates to return to the open position where it abuts the restriction pin 20.

At this time, the secondary balance weight 13 is pressed by the biasing force of the clip spring 18 so as to contact the restriction pin 20.

As described above, the reflectors M, ,M! When the balance weight 12.13 returns to the observation position, the balance weight 12.13
+, move in the opposite direction to Mz to eliminate camera vibration.

Once the series of photographic operations as described above have been completed, the winding lever 40 is rotated to release the film F and the shutter S.
and rolled up in a known manner. In response to this winding operation of the winding lever 40, the reflector lowering lever 28 rotates clockwise about the fixed shaft 22 against the biasing forces of the first charge spring 27 and the second charge spring 31. Both the first charge spring 27 and the second charge spring 31 are charged at the same time.

Also, by rotating the reflector lowering lever 28 in the clockwise direction, the tip 28a of the arm 28A of the reflector lowering lever 28 is rotated.
is separated from the bent portion 23a of the reflector lifting lever 23 which is locked by the first hook member 34. On the other hand, the pin 30 of the reflector lowering lever 28 comes into contact with the tip inclined part 36a of the second hook member 36, pushes up the inclined part 36a against the biasing force of the tension coil spring 35, and pushes up the inclined part 36a of the second hook member 36. It is locked by the hook and ready to shoot again.

In the above embodiment, when the main reflecting mirror M is in the observation position positioned by abutting the fixing pin 9 as shown in FIG. Further, the sub-balance weight 13 corresponding to the sub-reflector M2 is positioned in contact with the restriction pin 20. The groove width of the engaging groove 13C is formed to be slightly wider than the diameter of the fixing pin 7.17.
．． Reference numeral 18 acts to draw the gap created between the grooves 6C, 13C and the fixing pin 7.17 to one side while the sub-reflector M2 and the sub-balance weight 13 are in motion. Therefore, when the main reflecting mirror M1 moves up, the sub-reflecting mirror M2 operates with a moment's delay, but the sub-balancing weight 13 operates with a moment's delay from the main balancing weight 12, which descends almost at the same time as the main reflecting mirror M.

Therefore, the vibration caused by the main reflecting mirror M1 is caused by the main balance weight 12, and the vibration caused by the sub-reflector M2 is caused by the sub-balance weight 1.
2 are respectively erased. Since the interlocking mechanisms 15A and 15B are also interposed between the main reflecting mirror M and the main balancing weight 12, the main balancing weight 12 is slightly delayed with respect to the main reflecting mirror M, but the reflecting mirrors M1 and Ml Since the time required for raising and lowering the reflector M1 is extremely small, it hardly affects the vibration prevention of the camera.
, Ml and the balance weight 12.13 can be substantially synchronized.

In addition, in the above embodiment, when the main balance weight 12 moves to the lowered position as shown in FIG. 3, the sub balance weight 13 is configured to cover the window hole 12A of the main balance weight 12. However, in order to use the light-receiving element P for light control during flash photography, a notch hole is provided in the sub-balance weight 1@ through which light can pass, and the reflected light from the subject image formed on the film surface passes through this notch hole. The so-called TT
It may be configured to allow L dimming. Further, when the sub-balance weight 13 is in the open position as shown in FIG. 2, a notch may be provided in this portion so that a sufficient amount of light beam is incident on the light-receiving element P. In this case, if the mass of the secondary balance weight 13 is insufficient, a weight block made of a material with high specific gravity such as tungsten alloy may be added to the upper or lower surface of the secondary balance weight 13.

〔Effect of the invention〕

As described above, according to the present invention, since the main balance weight that mainly suppresses camera shake caused by the main reflecting mirror and the lucky balance weight that mainly suppresses camera shake caused by the sub-reflector are provided, a relatively simple interlocking mechanism is used. It is possible to effectively suppress vibrations caused by the sub-reflector, which cannot be ignored, and prevent camera shake. Therefore, there is an effect that the image quality of the photograph is further improved.

In addition, as shown in the embodiment, if the secondary balance weight is positioned parallel to the back of the main reflecting mirror when the main reflecting mirror is at the observation position, the shutter can be removed from the bottom of the main reflecting mirror. Since the light from the photographing lens that enters toward the blade can be cut by the secondary balance weight, there is no risk of light leaking to the film surface through the seam of the shutter blade. Reverse incident light that attempts to pass through the light-transmitting portion of the main reflecting mirror located at the position and enter the light receiving element can also be cut by this sub-reflecting mirror, allowing accurate TTL photometry and distance detection.Also, When the main reflector is in the retracted position, that is, while the shutter is open, the secondary balance weight covers the light receiving element (including the condensing lens), so the light passing through the photographic lens is reflected by the light receiving element. However, the reflected light does not become a ghost and reach the film surface.Therefore, it has the advantage that clear photographs can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIGS. 2 and 3 are longitudinal sectional views of a single-lens reflex camera incorporating the embodiment of FIG. 1, and FIG. 2 is a main reflector. Fig. 3 shows the state when the main reflecting mirror is in the observation position, Fig. 4 shows the main balance weight shown in Fig. 1, and Fig. 5 shows the state when the main reflecting mirror is in the retracted position. FIG. 6 is a sectional view taken along line B-8 in FIG. 4. [Explanation of symbols of main parts] Ml-main reflecting mirror, Ml-sub-reflecting mirror,

Claims (2)

[Claims] (1) A main reflector for viewfinder observation that is movable from an observation position on the photographic optical path to a retreat position outside the photographic optical path, and for guiding light from the photographing lens that has passed through a portion of the main reflector to the light receiving element. and a sub-reflector that is provided on the photographing optical path behind the main reflecting mirror and is movable together with the main reflecting mirror from the photographing optical path to a retracted position outside the photographing optical path. a main balance weight that moves in a direction opposite to the main reflection mirror in conjunction with the main reflection mirror and maintains dynamic balance mainly with the main reflection mirror; 1. An anti-vibration device for a single-lens reflex camera, comprising a sub-balance weight which is displaced in the direction and which maintains dynamic balance mainly with the sub-reflector. (2) The secondary balance weight (13) is the main balance weight (
12) Rotatably provided on the main reflecting mirror (M_1
) and the sub-reflector (M_2) move to the retracted position, the sub-balance weight (13) is configured to fold over the main balance weight (12). A vibration isolation device for a single-lens reflex camera according to claim 1.