JPH0695190B2 - Anti-vibration device for camera shutter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation device for a shutter, and more particularly to a vibration isolation device for a camera shutter that prevents vibration of a camera body due to a reaction when a shutter curtain or shutter blades travel.

In a camera equipped with a shutter having a light-shielding member (hereinafter simply referred to as a “light-shielding body”) such as a shutter curtain or a shutter blade that travels in one direction like a focal plane shutter, camera shake that occurs when the shutter is opened and closed is conventionally. , Mainly because of the impact when the light blocking body stopped traveling. Therefore, various anti-vibration means have been known which alleviate the impact and prevent the light-shielding body from bouncing at the same time as the camera shake.

On the other hand, in order to speed up the shutter more than a certain degree,
The traveling speed of the light shield itself has to be higher than that of the conventional one, but in order to meet the demand, it is necessary to increase the acceleration of the traveling light shield. Therefore, as a reaction against a large acceleration, the force received by the camera body inevitably increases in the direction opposite to the traveling direction of the light shield, and the displacement of the camera body, that is, the camera shake, cannot be ignored. Especially when the camera is attached to a support such as a tripod, the camera body displaced by the reaction of the light-shielding body while it is running tries to return to its original position due to the elasticity of the camera support as soon as the running is completed. Vibrates with the camera support. Moreover, since the vibration lasts for a long time, the camera shake continues, adversely affecting the photographed picture. The vibration occurs both when opening and closing the shutter, but the duration of the vibration after closing the shutter does not affect the photographed picture.

However, since the vibration when the shutter is opened adversely affects the photographed image, at least sufficient means must be provided to prevent the vibration caused by the reaction of the travel of the light shield to open the opening.

The camera shake caused by the reaction to the traveling of the shading body as described above causes the counterweight having an inertial mass almost equivalent to that of the shading body to run in the opposite direction at the same speed as the shading body according to the law of motion. This can be prevented by configuring so as to cancel the reaction force. However, it is difficult to secure a wide space in the narrow camera in which the counterweight can be moved by a distance substantially equal to that of the light shield.

In view of the above circumstances, it is an object of the present invention to provide a vibration isolator for a camera shutter having a counterweight means that can be installed in a narrow space of the camera without increasing the external dimensions of the camera.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of the present invention in a state where a shutter is charged, and FIG. 2 is an enlarged view of a II-II section of FIG. The shutter shown in FIG. 1 is a so-called vertically-running focal-plane shutter in which a front blade group and a rear blade group each including a plurality of shutter blades travel in a direction orthogonal to the longitudinal direction of the shotter opening for exposure. The blade structure is shown in FIG.

In FIG. 1, a shutter substrate 1 is provided with a shutter opening 2, and the shutter opening 2 is covered by a front blade group 3 composed of a plurality of blades. Also, the other rear blade group 4
The plurality of blades of the above are placed in a reserved position above the shutter opening 2 in an overlapping manner. In FIG. 3, a leading blade group 3 expanded to cover the opening 2 is a rectangular blade 3a supported by a leading blade driving arm 5 and an auxiliary arm 6 that form a known parallelogram link mechanism, and its rectangular shape. Five auxiliary blades for covering the rest of the opening 2 that cannot be covered by the blades 3a
It is composed of 3b, 3c, 3d, 3e and 3f. Rectangular feather 3a
An exposure end edge E formed on the upper part of is parallel to the inner edge of the opening 2 in the longitudinal direction. Further, the leading blade drive arm 5 and the auxiliary arm 6 are rotatably supported by pin shafts 7 and 8 provided side by side on the shutter substrate 1. Five auxiliary blades 3b to 3f are rotatably supported on the pin shaft 8 which supports the auxiliary arm. These leading blade groups 3 are driven by a leading blade driving lever 9 shown in FIG. 1, move to a retracted position below the shutter opening 2, and are superposed on each other. Also,
Similarly to the front blade group, the rear blade group 4 also has a rectangular blade supported by an auxiliary arm (see FIG. 3) of an equal blade drive arm that forms a parallelogram link mechanism, and a pin shaft that supports the auxiliary arm. It is composed of five auxiliary blades that can rotate in the center, and is configured to cover the shutter opening 2 by traveling downward after a predetermined delay time following the traveling of the leading blade group 3 and developing. ing.

The leading blade drive lever 9 for driving the leading blade group 3 is rotatably supported by a pin shaft 10 planted in the shutter substrate 1, as shown in FIGS. 1 and 2.
The leading blade drive spring 11 constantly urges the blade to rotate clockwise, and the rotation is blocked by the leading blade locking claw 12. Further, the leading blade driving pin planted at one end of the leading blade driving lever 9 penetrates the circular arc groove 1a formed in the shutter substrate 1 around the pin shaft 10 to form the cam groove of the leading blade driving arm 5. 5a is engaged. The leading blade drive pin 13 is engaged with a cam groove (not shown) formed on each of the five auxiliary blades 3b to 3f.

On the other hand, similarly to the front blade group 3, the rear blade group 4 has a rear blade driving lever 9 ', and a pin shaft 10' embedded in the shutter substrate 1.
Is rotatably supported by the rear blade and is urged by the rear blade drive spring 11 'so as to be rotatable in the clockwise direction at all times, and the rotation is blocked by the rear blade retaining claw 12'. In addition, the rear blade drive pin 13 'which is planted at one end of the rear blade drive lever 9'
The pin shaft 10 'is configured to penetrate through a circular arc groove 1b formed in the shutter substrate 1 and engage with cam grooves (not shown) formed in each of the trailing blade drive arm and the auxiliary blade.

A gear 14 is fixedly mounted on the leading blade drive lever 9, and both of them have a pin shaft.
It is configured so that it can rotate about 10. This gear 14
The segment gear 15 that meshes with is rotatably supported by a pin shaft 16 embedded in the shutter substrate 1. A bent plate 17 is integrally fixed to the segment gear 15, and a pin 18 is planted in a bent portion 17a of the bent plate 17. A bearing base 20 is fixedly mounted on the shutter substrate 1, and a weight drive shaft 19 that engages with the pin 18 is rotatably supported on the bearing base 20. The weight drive shaft 19 is provided so as to be parallel to the traveling surface of the front blade group 3 which is parallel to the shutter substrate 1, and the axis of the axis is parallel to the exposure edge E of the front blade group 3. Further, as shown in FIG. 14, the flange portion 19a formed at one end of the weight drive shaft 19 has a notch groove 19b for engaging the pin 18.
The pin 18 is always biased by a spring 21 so as to be pressed against one wall surface of the cutout groove 19b. By the engagement of the notch groove 19b and the pin 18, the rotation of the segment gear 15 is changed in direction and transmitted to the weight drive shaft 19 orthogonal to the pin shaft 16.

Further, the other end of the weight drive shaft 19 is connected to one end 22a of the counterweight 22.
A swinging arm 23 for supporting the is fixed as shown in FIGS. 2 and 5. Holding the counterweight 22, the bearing base 20
A support base 24 is fixedly mounted on the shutter substrate 1 at a position facing the support shaft 24, and the support shaft 24 is attached to the support base 24 in alignment with the axis of the weight drive shaft 19.
Has been planted. The supporting shaft 25 is the other end 22 of the counterweight 22.
A swing arm 23 'that supports b is rotatably supported via a push 26. Further, since the counterweight 22 and the swing arms 23, 23 'are integrally engaged, both ends 22a, 22b of the counterweight 22 are formed in a stepped shape, and the both ends 22a, 22b are shown in FIGS.
As shown in the figure, the bent portions 23 are formed on the swing arms 23 and 23 ', respectively.
They are connected by crimping by a and 23'a. Therefore, the counterweight 22 and the swing arms 23 and 23 'can be integrally swung about both the spindle drive shaft 19 and the support shaft 23. In this case, the balance weight 22 is brought close to the traveling surface of the front blade group 3, and the momentum of the balance weight 22 that is displaced in conjunction with the front blade group 3 and the momentum of the front blade group 3 are balanced, and It is necessary to reduce the space occupied by 22. Therefore, the displacement amount S of the counterweight 22 can be reduced, and the distance l from the swing center to the center of gravity G can be small.
In order to make the inertial mass of the counterweight 22 larger than the inertial mass of the front blade group, the counterweight 22 is made of tantalum (Ta) or tungsten (W), which has a larger specific gravity than lead, or an alloy such as 13.5. It is made of a metal or alloy having the above specific gravity.

FIG. 7 is a sectional view of the embodiment shown in FIG. 1 mounted on a single-lens reflex camera having a TTL photometric device.
In this camera, the light from the subject that has passed through the taking lens L ₁ is partially reflected by the oscillating mirror M _{1 and} is reflected by the focusing screen.
The image is formed on the SC, and the other part is reflected by the sub-mirror M ₂ after passing through the oscillating mirror M _1, and is formed on the photoelectric conversion element D via the image forming lens L _2. Has been done. A vertically-running focal-plane shutter is provided between the sub-mirror M ₂ and the film F, and the counterweight 22 is provided in the extremely narrow lower space S ₁ outside the passage of the photometric light flux on the front surface of the front shutter substrate 1 of the shutter. Is installed. In this case, the counterweight 22 is small and has a small amount of displacement, so that it can be installed without any trouble.

Since the first embodiment shown in FIGS. 1 to 7 is configured as described above, when a release button (not shown) provided on the camera body is pressed, the leading blade hooking pawl is formed by a known method.
12 rotates counterclockwise to release the restraint of the leading blade drive lever 9. When the leading blade drive lever 9 is released, the leading blade drive lever 9 is rotated clockwise by the urging force of the leading blade drive spring 11, and the leading blade drive arm 5 is rotated clockwise about the pin shaft 7 via the leading blade drive pin 13. Move, and with the help of the auxiliary lever 6, translate the rectangular blade 3a downwards. At the same time, the leading blade drive lever 9 rotates the auxiliary blades 3b to 3f in the clockwise direction around the pin shaft 8 via the leading blade drive pin 13 and moves them together with the rectangular blade 3a to the retracted position below the opening 2. Let
Exposure is performed.

On the other hand, the clockwise rotation of the leading blade drive lever 9 causes the gear 14 to rotate clockwise, and the segment gear 15 meshing with the gear 14 to rotate counterclockwise. By the counterclockwise rotation of the segment gear 15, the pin 18 rotates counterclockwise about the pin shaft 16 via the bending plate 17 fixed to the segment gear 15. The rotation of the pin 18 in the counterclockwise direction causes the pin 18 to be displaced leftward in FIG. 4, so that the flange of the weight drive shaft 19 is engaged via the notch groove 19b engaging with the pin 18. The portion 19a is rotated clockwise. The counterclockwise rotation of the flange portion 19a causes the counterweight 22 to move together with the swing arms 23 and 23 ', the weight drive shaft 19 and the support shaft 25.
Rotate clockwise about both axes to the position shown by the chain line in FIG. Therefore, the center of gravity G of the counterweight 22
Is displaced to the left in FIG. 6 by a distance S. This displacement direction is opposite to the traveling direction of the rectangular blade 3a. Also,
Although the auxiliary blades 3b to 3f are rotationally displaced about the pin shaft 8, the center of gravity of each auxiliary blade 3b to 3f is not displaced much in the left-right direction (lateral direction) in FIG. 3 when the shutter travels. However, since the large displacement is made substantially only in the vertical direction (vertical direction), it can be considered that the entire front blade group including the rectangular blade 3a travels in the vertical direction. In other words, it can be considered that the vehicle travels in the direction perpendicular to the exposure edge of the rectangular blade 3a. Therefore, if the product (ms) of the inertial mass (m) of the counterweight 22 and the amount of movement of its center of gravity (ms) is made approximately equal to the product of the inertial mass of the leading blade group 3 and the amount of movement of its center of gravity, Since the balance weight 22 and the front blade group 3 have substantially the same momentum and the opposite directions of movement, the reaction between them is offset.
However, in this case, the product of the inertial mass of the front blade group 3 and the amount of movement of the center of gravity is the inertial mass m ′ of each blade (3a to 3f).
Is the total sum (Σm ′ · s ′) of the product of and the shift amount s ′ of the center of gravity. Therefore, by making the inertial mass (m) of the counterweight 22 sufficiently larger than the inertial mass of the leading blade group 3,
Even if the amount of movement (s) of the center of gravity of 22 is extremely small, it is possible to achieve a balance with the front blade group 3, and it is possible to almost prevent vibrations due to the front blade traveling of the camera body.

In the embodiment of FIG. 1, the leading blade travels downward and the leading blade driving lever 9 is provided below the trailing blade driving lever 9 ', so that the counterweight 22 is below the shutter opening 2 in the shutter substrate. It is provided above. However, among the vertically-running focal-plane shutters, a type in which the leading blade and the trailing blade travel in the direction (upward) opposite to the shutter shown in FIG. 1 is generally used. FIG. 8 is a plan view showing a second embodiment of the present invention incorporated in a vertically running type focal plane shutter whose blades travel upward. This second embodiment corresponds to a vertically inverted version of the first embodiment shown in FIG. 1, and the functions of the constituent members used therein are the same as those in FIG. Therefore, in the embodiment shown in FIG. 8, all members having the same functions as those in the first embodiment are designated by the same reference numerals as those in FIG. 1, and the detailed description of the structure is omitted.

In the second embodiment shown in FIG. 8, when a shutter button (not shown) is pressed, the leading blade drive lever 9 that was locked by the leading blade locking claw 12 is released from its restraint, and the leading blade drive spring 11 is released. It is rotated counterclockwise about the pin shaft 10 by the urging force of. By the rotation of the leading blade driving lever 9, the leading blade 3 travels upward through the leading blade driving pin 13.

On the other hand, by rotating the leading blade drive lever 9 counterclockwise,
The pin 18 rotates clockwise about the pin shaft 16 via the gear 14, the segment gear 15, and the bending plate 17, and the balance drive weight 19 having the flange 19a and the counterweight 22 via the swing arm 23. In FIG. 8, it is pivotally displaced downward. The displacement direction of the counterweight 22 is opposite to the direction of travel of the leading blades 3, and the specific gravity of the counterweight 22 is set to be approximately 13.5 or higher than that of lead so that the momentum of both is balanced. Is larger than the inertial mass of the leading blade.
Therefore, also in the second embodiment, the counterweight 22 can be formed in a small size, and the displacement thereof can be made extremely small. Therefore, the space required for the counterweight 22 may be extremely small. Therefore, in the second embodiment, the counterweight 22 is provided above the oscillating mirror M ₁ as shown in FIG.
It can be installed in an extremely narrow space S ₂ between the SC and the shutter substrate 1.

In each of the vertical-traveling focal-plane shutters in the above-described embodiments, as shown in FIG. 3, a rectangular blade in which a light shield moves in parallel by a parallelogram link mechanism including a drive arm and an auxiliary arm, and this rectangular blade. And a plurality of auxiliary blades that rotate about the pin axis to cover the remaining portion of the shutter opening that cannot be covered by. However, in the shutter used in the present invention, a plurality of rectangular blades are connected to a drive arm and an auxiliary arm that form a parallelogram linkage mechanism, and such rectangular blades move in parallel to open and close the shutter opening. It can be made in. Further, since the vibration prevention device of the present invention can be installed in an extremely narrow space, it can be effectively applied not only to the focal plane shutter provided immediately before the film but also to the behind shutter provided immediately after the taking lens.

As described above, according to the present invention, the counterweight that moves in the direction opposite to the light shield in conjunction with the traveling of the light shield can be formed in a small size, and its displacement amount can be made extremely small. It can be installed in a space, and can sufficiently prevent camera shake.

Further, the camera shake caused by the travel of the shutter front blade has a greater influence on the photographing result than the camera shake caused by the travel of the shutter rear blade group. However, the present invention is limited to the shutter opening light shield (front blade group). Since a counterweight is provided and no counterweight is provided on the shutter closing light-shielding body (rear blade group), the shutter closing light-shielding body is provided with no counterweight. Compared with the case, the number of parts can be significantly reduced.

Also, the shutter drive mechanism section usually has a layered structure, but if a new anti-vibration mechanism is to be provided, it is necessary to newly provide another layer or increase the size of the conventional layer. Also leads to an increase in the size of the shutter. However, according to the present invention, since the vertical axis for providing the counterweight interlocking with the leading blade group is provided outside the driving locus of the drive lever that drives the leading blade group, compared with the case where it is provided within the driving locus. The vibration isolation mechanism can be provided without increasing the height or size of the shutter drive mechanism section. In addition, a region outside the movement locus of the drive lever is a dead space. In the present application, the dead space is used to arrange the anti-vibration mechanism, so that the shutter does not become large. Further, by disposing the shaft outside the movement locus of the drive lever, the structure of the mechanism is not complicated.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment in which the present invention is applied to prevent vibration of a leading blade, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 shows a structure of a shutter blade of FIG. FIG. 4 is a plan view, FIG. 4 is a sectional view taken along line IV-IV of FIG. 2, FIG. 5 is a sectional view taken along line VV of FIG. 2, FIG. 6 is a sectional view taken along line IV-IV of FIG. 2, and FIG. FIG. 8 is a sectional view showing the embodiment of FIG. 1 mounted on a single-lens reflex camera, FIG. 8 is a plan view showing the second embodiment of the present invention, and FIG. 9 is a diagram showing the embodiment of FIG. It is the equipped sectional view. 1 ... Shutter substrate 3, 4 ... Shading body 19, 19 ', 25, 25' ... Spindle 22, 22 '... Balance weight E ... Exposure edge

Claims (1)

[Claims] 1. A shutter substrate having an opening, and a state in which the shutter substrate is unfolded so as to cover the opening at the time of photographing.
First folded and moving in a direction of retracting from the opening
A light blocking member, a first drive lever for driving the first light blocking member, and a second movable state which is unfolded and retracted from the opening at the time of photographing, and which is unfolded to cover the opening.
A light blocking member, a rear drive lever for driving the second light blocking member, a shaft vertically provided on the shutter substrate outside the movement locus of the first drive lever, rotatably provided on the shaft, And a counterweight that rotates in a direction opposite to the moving direction of the first light-shielding member according to the rotation of the interlocking device, and the second light-shielding member. An anti-vibration device for a camera shutter, which is not provided with a counterweight for canceling vibrations and impacts caused by movement or stop of the camera.