JP3287079B2 - Anti-vibration device for focal plane shutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator for a focal plane shutter for a camera.

[0002]

2. Description of the Related Art In a focal plane shutter for a camera, a so-called double light-shielding type shutter has been proposed in which a shutter opening is covered with both shutter curtains of a front curtain group and a rear curtain group in a charge completed state before the start of exposure. ing. Also, 2
An anti-vibration device that cancels the vibration generated by the travel of the shutter curtain of a heavy light shielding type shutter is disclosed in, for example,
-361243.

[0003] This conventional vibration isolator is provided with one balance weight for a return operation of a rear curtain group for releasing a double light blocking state after release and a traveling operation of a front curtain group for subsequent exposure. Are moved in the directions opposite to the respective operation directions, thereby producing an anti-vibration effect. Since the direction of the return operation of the rear curtain group and the traveling operation of the front curtain group are opposite, the balance weight reciprocates by this series of operations.

[0004]

However, as disclosed in Japanese Patent Application Laid-Open No. 61-251830, in a double light-blocking type shutter, the rear curtain group travels in a double light-blocked state when charging is completed. In the shutter of the type that returns to the position immediately before the time brake is applied, the stroke of the return operation of the rear curtain group and the stroke of the traveling operation of the front curtain group are different (the return operation stroke of the rear curtain group is (Short), there is a problem that a sufficient anti-vibration effect cannot be obtained in both the running operation of the front curtain group and the returning operation of the rear curtain group simply by reciprocating one balance weight by the same stroke. is there.

For example, if the setting is made so that the anti-vibration effect is optimal for the running operation of the front curtain group, the anti-vibration effect becomes excessive for the returning operation of the rear curtain group. If the setting is optimally performed for the return operation of the front curtain group, the anti-vibration effect is insufficient for the traveling operation of the front curtain group.

Even if the stroke of the return operation of the rear curtain group and the stroke of the traveling operation of the front curtain group are the same, the masses of the front curtain group and the rear curtain group are different due to different shapes and materials. In this case as well, if setting is performed such that the anti-vibration effect is optimal for one of the operations of the front curtain group or the rear curtain group, the anti-vibration effect becomes excessive or insufficient for the other operation. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Even when the return moment of the rear curtain group is different from the traveling moment of the front curtain group, the rear curtain group and the front curtain group have different movement moments. The purpose is to minimize the vibrations associated with running.

[0008]

According to the present invention, in order to achieve the above object, the rear curtain group returns to a start position from a state in which a shooting screen is doubly shaded, in order to cancel a double shaded state, Thereafter, the exposure is started when the front curtain group starts running, and the exposure is completed when the rear curtain group runs after a predetermined time has elapsed from the start of running of the front curtain group. In the vibration isolator,
The balancer includes a return mechanism for the rear curtain group and balancer means including a balance weight, and is configured to reciprocate the balancer means in conjunction with the return operation of the rear curtain group and the traveling operation of the front curtain group. The stroke is configured to be different between a case where the stroke is interlocked with the return operation of the rear curtain group and a case where the stroke is interlocked with the traveling operation of the front curtain group.

[0009]

In the above-structured vibration isolator for the focal plane shutter, the stroke of the balancer means is different between the case where the stroke is interlocked with the return operation of the rear curtain group and the case where it is interlocked with the running operation of the front curtain group. Therefore, by varying the stroke of the balancer means according to the difference between the moving moment of the returning operation of the rear curtain group and the moving moment of the traveling operation of the front curtain group, vibrations caused by the traveling of the rear curtain group and the front curtain group are respectively It can be prevented to the maximum.

[0010]

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

FIGS. 1 and 2 are a plan view and a side view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention, and both show a charge completed state before the start of exposure.

In FIG. 1, an opening 1a for exposure is opened in a substrate 1. Reference numeral 3 denotes a front curtain group driving lever rotatably mounted around a shaft 4 implanted in the substrate 1, and has one end rotated clockwise by a front curtain group driving spring 6 fixed to the substrate 1. Being energized. A locking portion 3 a is formed at the tip of the front curtain group drive lever 3.

Reference numeral 5 denotes a front curtain group pin planted near the front end of the front curtain group drive lever 3. The front curtain group pin 5 extends to the opposite side of the substrate 1 through a crescent-shaped hole 1b opened in the substrate 1 so as to cover the rotation trajectory of the front curtain group pin 5, and a plurality of divided shutter curtains Are connected to a front curtain group 46 constituted by The rotation of the front curtain group drive lever 3 also drives the front curtain group 46. The first curtain group pin 5
1A, the front curtain group 46 is unfolded and covers the opening 1a, which will be described with reference to FIG. 1B.

Reference numeral 7 denotes a front curtain group locking key rotatably mounted around a shaft 8 implanted in the substrate 1. At the tip of the locking key 7 of the front curtain group, a locking portion 7 a bent toward the substrate 1 is formed. The front curtain group locking key 7 is urged to rotate clockwise by a spring 9 having one end fixed to the substrate 1, but as shown in FIG. Limited. In a state where the front curtain group locking key 7 is in contact with the pin 10, the locking section 7 a engages with the locking section 3 a of the front curtain group driving lever 3 to drive the front curtain group driving lever 3. The clockwise rotation due to the urging force of the spring 6 is locked, and the front curtain group locking key 7 rotates counterclockwise against the urging force of the spring 9 to engage the locking portion 7a with the locking portion 3a. When the combination is released, the front curtain group drive lever 3 rotates clockwise by the urging force of the front curtain group drive spring 6.

Reference numeral 11 denotes a front curtain group brake lever rotatably mounted on a shaft 12 implanted in the substrate 1 and shows a reset state thereof. The front curtain group brake lever 11 is configured so that frictional means exerts a resisting force against movement in the rotational direction. The cam surface 11a of the front curtain group brake lever 11 is arranged so as to face the rotation locus of the front curtain group pin 5, and the front curtain group pin 5 is
1a, the front curtain group pin 5 is moved to the brake lever 11
, A resistance is applied to the clockwise rotation of the front-curtain group pin 5 and the front-curtain group drive lever 3 in the vicinity of the end position thereof to perform a braking action. Further, at the position where the front curtain group brake lever 11 is pushed by the front curtain group pin 5 and rotates clockwise, and the contact surface 11b comes into contact with the front curtain group brake stopper 13 implanted on the substrate 1, The clockwise rotation of the front curtain group pin 5 and the front curtain group drive lever 3 is restricted. When the front curtain group pin 5 has reached the clockwise rotation limit position, the front curtain group 46 is folded below the opening 1a to open the opening 1a.

Reference numeral 14 denotes a rear curtain group drive lever rotatably mounted around a shaft 15 implanted in the substrate 1. The rear curtain group drive lever 14 is urged to rotate clockwise by a rear curtain group drive spring 16 having one end fixed to the substrate 1. A contact portion 14a is formed at the end of the rear curtain drive lever 14, and a contact portion 14b bent toward the substrate 1 is formed near the middle.

Reference numeral 17 denotes a rear curtain group locking key rotatably mounted around a shaft 18 implanted in the substrate 1. A locking portion 17a bent toward the substrate 1 is formed at the tip of the locking key 17 of the rear curtain group. Rear curtain lock 17
Is biased to rotate clockwise by a spring 19 fixed at one end to the substrate 1, but the rotation is restricted by a pin 20 as shown in FIG.
When the rear curtain group locking key 17 is in contact with the pin 20, the locking portion 17a is engaged with the contact portion 14a of the rear curtain group drive lever 14, and the rear curtain group drive lever 14 is driven. The clockwise rotation by the urging force of the spring 16 is locked. When the rear curtain group locking key 17 rotates counterclockwise against the urging force of the spring 19 and the engagement between the locking portion 17a and the contact portion 14a is released, the rear curtain group driving lever 14 is moved rearward. The curtain group drive spring 16 rotates clockwise by the urging force.

A rear curtain group lever 21 is rotatably mounted on the shaft 18 coaxially with the rear curtain group drive lever 14. The rear curtain group lever 21 has a contact portion 21a and a contact portion 21b. The rear curtain group lever 21 is disposed between the substrate 1 and the rear curtain group drive lever 14.

Reference numeral 22 denotes a rear curtain group pin implanted near the tip of the rear curtain group lever 21. The rear curtain group pin 22 extends to the opposite side of the substrate 1 through a crescent-shaped hole 1c opened in the substrate 1 so as to cover the rotation trajectory of the rear curtain group pin 22, and a plurality of divided shutter curtains. Is connected to the rear curtain group 47 composed of The rotation of the rear curtain group lever 21 also drives the rear curtain group 47. Note that the rear curtain group pin 22
1 (a), the rear curtain group 47 is almost completely covered except for the area below the opening 1a, as will be described with reference to FIG. 1 (b).

Reference numeral 23 denotes a rear curtain group return spring that is bridged between the rear curtain group drive lever 14 and the rear curtain group lever 21. The rear curtain group return spring 23 urges the rear curtain group drive lever 14 and the rear curtain group lever 21 in a direction in which the contact part 21a and the contact part 14a come into contact with each other. When both levers are integrated and the rear curtain group drive lever 14 is at the position shown in FIG. 1A, the rear curtain group 47 is folded over the opening 1a to open the opening 1a.

Reference numeral 24 denotes a rear curtain group brake lever rotatably mounted around a shaft 25 implanted in the substrate 1, and shows a reset state of the brake lever. The rear curtain group brake lever 24 is configured such that a frictional means exerts a resisting force on the movement in the rotational direction. The cam surface 24a of the rear curtain group brake lever 24 is disposed so as to face the rotation locus of the rear curtain group pin 22, and after the rear curtain group pin 22 contacts the cam surface 24a, the rear curtain group pin 22 is moved. Since the brake lever 24 is pressed, a resistance is exerted near the end position of the rear curtain group pin 22 and the clockwise rotation of the rear curtain group lever 21 in the vicinity of the end position to perform a braking action. Further, the rear curtain group brake lever 24 is pushed by the rear curtain group pin 22 and rotates counterclockwise, so that the contact surface 24b abuts on the rear curtain group brake stopper 26 implanted in the substrate 1. The clockwise rotation of the rear curtain group pin 22 and the rear curtain group lever 21 is restricted.
When the rear curtain group pin 22 has reached the clockwise rotation limit position, the rear curtain group 47 is unfolded and covers the opening 1a.

Reference numeral 27 denotes a balancer lever rotatably mounted around a shaft 29 implanted in the substrate 1, and has a long hole 27a formed at the end thereof. The rotation of the balancer lever 27 is controlled by the balancer return stopper 44 and the balancer travel stopper 45 implanted on the substrate 1.
Restricts the counterclockwise rotation and the clockwise rotation, respectively. Reference numeral 28 denotes a balance weight integrally attached to substantially the center of the balancer lever 27, and is configured such that the rotation of the balancer lever 27 moves the center of gravity G in the vertical direction (FIG. 1). By moving the balance weight in the direction opposite to the direction of movement of the center of gravity of the front curtain group 46 or the rear curtain group 47 and moving them synchronously (in conjunction with each other) in terms of timing, the vibrations generated by these shutter curtain groups are canceled. To obtain an anti-vibration effect.

Reference numeral 30 denotes a balancer return lever rotatably attached around a shaft 33 implanted on the substrate 1. The balancer return lever 30 has a locking portion 30a bent to the opposite side to the substrate 1 on one of the arms extending in three directions.
Is formed on the other arm, and a contact portion 30b bent to the opposite side to the substrate 1 is formed on the other arm, and the connecting pin 32 is formed on the remaining arm.
Is attached. The connecting pin 32 is slidably fitted in the elongated hole 27a of the balancer lever 27, so that the balancer lever 27 and the balancer return lever 30 are configured to operate in conjunction. That is, when the balancer return lever 30 rotates clockwise, the balancer lever 27 rotates counterclockwise, and operates in conjunction with the opposite direction.

Reference numeral 31 denotes a balancer traveling lever which is rotatably mounted around the shaft 33 coaxially with the balancer return lever 30. A locking portion 31a is formed at one end of the balancer travel lever 31, and a contact portion 31b bent at a direction opposite to the substrate 1 is formed at the other end, and a balancer having one end fixed to the substrate 1 is provided. Running spring 35
Urged to rotate counterclockwise.
The balancer return lever 30 is disposed between the substrate 1 and the balancer travel lever 31.

Numeral 34 denotes a balancer return spring which is bridged between the balancer return lever 30 and the balancer travel lever 31. The contact portion 30b abuts on the contact portion 31b and the balancer return lever 30 and the balancer travel lever 31.
Are biased in the direction of integration.

Reference numeral 36 denotes a balancer travel locking lever rotatably mounted around a shaft 37 implanted in the substrate 1. The balancer travel locking lever 36 has a distal end bent toward the opposite side to the substrate 1. A locking portion 36a is formed, and one end is urged to rotate clockwise by a spring 38 fixed to the substrate 1.
As shown in (a), the rotation is restricted by the pin 39. The balancer travel locking lever 36 is pin 39
In a state where the balancer running lever 31 is in contact with the locking portion 36a, the locking portion 36a is engaged with the locking portion 31a of the balancer travel lever 31, and stops the counterclockwise rotation of the balancer travel lever 31 due to the urging force of the balancer travel spring 35. ing. When the balancer running locking lever 36 rotates counterclockwise against the biasing force of the spring 38, and the engagement between the locking portion 36a and the locking portion 31a is released, the balancer running lever 31 moves the biasing force of the balancer running spring 35. Rotates counterclockwise.

Reference numeral 40 denotes a return locking lever rotatably mounted around a shaft 41 implanted in the substrate 1. The return locking lever 40 has a locking portion 40a bent at one end on the opposite side to the substrate 1 and a locking portion 40b at the other end.
Are formed. One end of the return locking lever 40 is urged to rotate clockwise by a spring 42 fixed at one end to the substrate 1, but its rotation is restricted by a pin 43 as shown in FIG. ing. When the return locking lever is in contact with the pin 43, the locking portions 40a and 40b engage with the abutting portion 21a of the rear curtain group lever 21 and the locking portion 30a of the balancer return lever 30, respectively. The counterclockwise rotation of the curtain group lever 21 by the rear curtain group return spring 23 and the clockwise rotation of the balancer return lever 30 by the balancer return spring 34 are locked. The return locking lever 40 rotates counterclockwise against the urging force of the spring 42, and the engagement between the locking portion 40a and the contact portion 21a and the engagement between the locking portion 40b and the locking portion 30a are released. Then, the rear curtain group lever 21 is rotated counterclockwise by the urging force of the rear curtain group return spring 23, and the balancer return lever 30 is rotated.
Is rotated clockwise by the biasing force of the balancer return spring 34.

In the reset state of the rear curtain group brake lever 24, the contact portion 21a and the locking portion 40a are arranged so that the rear curtain group lever 21 is located at a position where the rear curtain group pin 22 does not contact the cam surface 24a. Is determined.

In FIG. 1B, reference numeral 1 denotes a substrate, and 2 denotes a substrate shown in FIG.
This is a cover plate not shown in FIG. Cover plate 2
Has an opening 2a similar to the opening 1a of the substrate 1. Reference numerals 46 and 47 are a front curtain group and a rear curtain group, respectively, and 46a and 47a are respective slit edges. In the charging completed state shown in FIG. 1B, the front curtain group 46 covers the openings 1a and 2a as described above, but the rear curtain group 47 has the slit edge 47a in the openings 1a and 2a. It is located below, with the openings 1a and 2a slightly open.

The front curtain group 46 and the rear curtain group 47 shown in the embodiment have the same configuration, and therefore have substantially the same equivalent mass. Vibration occurs approximately in proportion to the equivalent mass.

The configuration of the main part of the shutter according to the present invention has been described above. Next, the operation of the shutter of the present invention will be described.

When the release button of the camera is pressed, a mirror and an aperture mechanism (not shown) operate. At about the same time, the release locking lever 40 first rotates counterclockwise against the urging force of the spring 42 by the release mechanism (not shown) from the state shown in FIGS. The engagement between the engagement portion 40a and the contact portion 21a and the engagement between the engagement portion 40b and the engagement portion 30a are released. The rear curtain group lever 21 rotates counterclockwise by the urging force of the rear curtain group return spring 23, and
b comes into contact with the contact portion 14b of the rear curtain group drive lever 14.
Therefore, the rear curtain group 47 connected to the rear curtain group pin 22 performs a return operation of moving upward, is folded above the opening 1a, returns to its start position, and enters a state where the opening 1a is opened. .

On the other hand, almost simultaneously with the start of the return operation of the rear curtain group 47, the balancer return lever 30 is
4, the balancer lever 27 and the balance weight 28 connected by the connecting pin 32 rotate counterclockwise, and as a result, the center of gravity G of the balance weight 28 moves downward (FIG. 1). ) To start moving. Almost simultaneously with the end of the return operation of the rear curtain group 47, the contact portion 30b contacts the contact portion 31b of the balancer travel lever 31, and the rotation of the balancer return lever 30 is stopped. The movement also stops. As described above, the balance weight 28 moves in the opposite direction substantially in synchronization (interlocking) with the return operation of the rear curtain group 47, and
The vibration caused by the return operation of the above is canceled.

FIG. 2 shows a state before the start of exposure after the above operation is completed. At this time, the balancer lever 27 is not in contact with the balancer return stopper 44, but the position of the balancer return lever 30 is determined by the balancer travel lever 31 locked by the balancer travel lock lever 36, whereby Balancer lever 27
Is determined so as to determine the position. However, since it is the balancer running spring 35 that receives the impact when the counterclockwise rotation of the balancer lever 27 stops, the balancer return stopper 44 has a role of regulating the overrun of the balancer lever 27 when the balancer lever 27 overruns. I have.

From the state shown in FIG. 2, the front curtain group locking key 7 rotates counterclockwise against the urging force of the spring 9 by a mechanism (not shown), and the locking portion 7a and the front curtain group driving lever are rotated. Locking part 3 of 3
a is released, and the balancer travel locking lever 36 is released.
Rotates counterclockwise against the urging force of the spring 38, and the locking portion 36a and the locking portion 31a of the balancer travel lever 31 are rotated.
Is disengaged. Then, the front curtain group drive lever 3 starts rotating clockwise by the urging force of the front curtain group drive spring 6,
The front curtain group 46 connected to the front curtain group pin 5 is downward (FIG. 2).
, The opening operation is started, and the exposure is started. When the front curtain group pin 5 rotates to a position where it comes into contact with the cam surface 11a of the front curtain group brake lever 11, the front curtain group brake lever 11 applies resistance to the front curtain group pin 5 and the front curtain group drive lever 3. The front curtain group pin 5 and the front curtain group drive lever 3 stop at the position where the braking action is performed and the contact surface 11b contacts the front curtain group brake stopper 13, and the traveling operation of the front curtain group 46 ends.
At this time, the front curtain group 46 is folded below the opening 1a to open the opening 1a.

On the other hand, almost simultaneously with the start of the running operation of the front curtain group 46, the balancer running lever 31 starts rotating counterclockwise. Here, the contact portion 30b of the balancer return lever 30 is moved by the biasing force of the balancer return spring 34.
1b, that is, the balancer return lever 3
0 starts rotating counterclockwise integrally with the balancer travel lever 31, and the balancer lever 27 also starts rotating clockwise, so that the balance weight 28 starts moving upward (FIG. 2). . Almost simultaneously with the end of the traveling operation of the front curtain group 46, the balancer lever 27 abuts against the balancer traveling stopper 45 and stops, and the balance weight 28 also stops moving upward (FIG. 2). At this time,
The balancer return lever 30 and the balancer travel lever 31 also stop. In this way, the balance weight 28 moves in the opposite direction substantially in synchronization (interlocking) with the traveling operation of the front curtain group 46, and the vibration caused by the traveling operation of the front curtain group 46 is canceled.

FIG. 3 shows a state in which the running operation of the front curtain group 46 has been completed. From the state shown in FIG. 3, the rear curtain group locking key 17 rotates counterclockwise against the urging force of the spring 19 by a mechanism not shown, and the engagement between the locking portion 17a and the contact portion 14a is performed. Is released. Then, the rear curtain group drive lever 14 starts rotating clockwise by the urging force of the rear curtain group drive spring 16, and the rear curtain group lever 21 also comes into contact with the contact portion 21 b by the urging force of the rear curtain group return spring 23. With the abutting portion 14b abutting, the rotation starts clockwise integrally with the rear curtain group drive lever 14. Accordingly, the rear curtain group 47 connected to the rear curtain group pin 22 starts a traveling operation of moving downward (FIG. 3), and the opening 1a is started to be covered by the rear curtain group 47. And the rear curtain group pin 22 is the cam surface 2 of the rear curtain group brake lever 24.
4a, the rear curtain group brake lever 24 applies a resistive force to the rear curtain group pin 22, the rear curtain group lever 21, and the rear curtain group drive lever 14 to be braked, and the contact surface 24b is moved. Rear curtain brake stopper 26
The rear curtain group pin 22, the rear curtain group lever 21, and the rear curtain group drive lever 14 are stopped at the position where they are in contact with, and the traveling operation of the rear curtain group 47 is completed and the exposure is completed. At this time, the rear curtain group 47 is unfolded and covers the opening 1a. At this time, the front curtain group 46 and the rear curtain group 47 are driven with a time difference at which a predetermined exposure time can be obtained. FIG. 4 shows a state where the exposure is completed. Then, from the state shown in FIG. 4, a charging operation is performed by a charging mechanism (not shown). First, the return locking lever 40 is pushed by the pin 4 by the urging force of the spring 42.
3 is reset to the position where it abuts.

Next, the front curtain group driving lever 3 is rotated counterclockwise against the urging force of the front curtain group driving spring 6, and
Comes to a position where it can be engaged with the locking portion 7a, the front curtain group locking key 7 is reset to a position where it comes into contact with the pin 10 by the urging force of the spring 9, and the locking portion 3a is engaged with the locking portion 7a. Then, the front curtain group brake lever 11 is further rotated clockwise to reset to the state shown in FIG.

Further, the rear curtain group drive lever 14 is rotated counterclockwise against the urging force of the rear curtain group drive spring 16, and the contact portion 14a comes to a position where it can be engaged with the locking portion 17a. By the way, the rear curtain group locking key 17 is pushed by
The contact portion 14a is reset to a position where it comes into contact with zero, and the contact portion 14a is engaged with the locking portion 17a. At this time, the rear-curtain group lever 21 also rotates with the rotation of the rear-curtain group drive lever 14.
However, after the contact portion 21a engages with the locking portion 40a, the rear curtain group lever 21 remains at that position, and the rear curtain group drive lever 14 rotates to rotate the rear curtain group. The rear curtain group return spring 23 is also charged together with the drive spring 16. Further, the rear curtain group brake lever 24 is rotated clockwise to reset to the state shown in FIG.

Subsequently, the balancer running lever 31 is rotated clockwise, and when the locking portion 31a comes to a position where it can be engaged with the locking portion 36a, the balancer running locking lever 36 is rotated.
Is reset to a position where it comes into contact with the pin 39 by the urging force of the spring 38, and the locking portion 31a is engaged with the locking portion 36a. At this time, the balancer return lever 30 is also rotated with the rotation of the balancer travel lever 31.
However, the balancer return lever 30 stays at that position after the engagement portion 30a engages with the engagement portion 40b, and the balancer return spring 31 is rotated together with the balancer travel spring 35 by the rotation of the balancer travel lever 31. The spring 34 is also charged. The balancer lever 27 and the balance weight 28 also stop when the balancer return lever 30 stops. By the above charging operation, FIG.
State.

Next, the returning operation of the rear curtain group 47, the front curtain group 46
5 and the operation relationship of the balance weight 28, particularly their strokes, will be described with reference to FIG. FIG.
9 is a front view showing the movement of the center of gravity of the rear curtain group 47 due to the return operation and the movement of the center of gravity of the front curtain group 46 due to the running operation.

In FIG. 5, when the rear curtain group 47 returns, the rear curtain group pin 22 moves from the A position to the B position, and the center of gravity of the rear curtain group 47 moves from the GA position to the GB position.
On the other hand, when the front curtain group 46 travels, the front curtain group pin 5 moves from the B 'position to the C position, and the center of gravity of the front curtain group 46 moves from the GB' position to the GC position. Here, D of the rear curtain group pin 22
The position is the position where the running operation of the rear curtain group 47 shown in FIG. 4A is completed, and the stroke between the B and D of the rear curtain group pin 22 and the stroke between the B 'and C of the front curtain group pin 5 Are equal. Therefore, the stroke between AB is B'-C
The center of gravity movement distance (GA to GB) of the rear curtain group 47 during the return operation is shorter than the center of gravity movement distance (GB 'to GC) of the front curtain group 46 during the running operation. .

FIG. 6 is a front view showing the movement of the center of gravity of the balance weight 28 during the return operation of the rear curtain group 47 and the running operation of the front curtain group 46. 6, when the rear curtain group 47 returns, the center of gravity of the balance weight 28 moves from the position A to the position B in a direction opposite to the direction of movement of the center of gravity of the rear curtain group 47 shown in FIG. On the other hand, during the traveling operation of the front curtain group 46, the center of gravity of the balance weight 28 moves from the position B to the position C in a direction opposite to the moving direction of the center of gravity of the front curtain group 46 shown in FIG. Here, the moving distance of the center of gravity of the balance weight 28 is shorter in the moving distance (A to B) of the rear curtain group 47 during the return operation than in the moving operation of the front curtain group 46 (B to C). Has become.

As described above, since the stroke of the balance weight 28 is set to the stroke corresponding to each of the returning operation of the rear curtain group 47 and the traveling operation of the front curtain group 46, the rear curtain group 4
Vibrations generated by both the return operation of the front curtain 7 and the traveling operation of the front curtain group 46 are canceled out in a well-balanced manner.

FIGS. 7 and 8 show a second embodiment of the present invention, in which the balancer traveling stopper 45 is improved. FIG. 7A is a plan view thereof, and FIG.
FIG. 3A is a sectional view taken along line AA of FIG. As shown in FIG. 7B, the balancer travel stopper 45 is attached to the substrate 1 by its eccentrically arranged shaft portion 45a, and is rotatable around the shaft portion 45a. There is no structure. Incidentally, an appropriate resistance force acts in the rotation direction, and it is possible to hold the disk at an arbitrary position.

FIG. 8 is a front view in which the balancer traveling stopper 45 shown in FIG. 7 is applied to the stopper of the balancer lever 27. Adjust the balancer travel stopper 45 to the shaft 45
When rotated around a, the stop position of the balancer lever 27 in the clockwise direction can be changed, that is, the position C in FIG. 6 can be changed. Therefore, it is possible to easily change only the moving distance of the center of gravity of the balance weight 28 corresponding to the running operation of the front curtain group 46.

Therefore, it is possible to easily change the stroke distribution of the balance weight 28 at the time of the return operation of the rear curtain group 47 and at the time of the running operation of the front curtain group 46, and to adjust the variation in the stroke distribution between the two during manufacturing. Can be.

As described above, according to the embodiment of the present invention, the moving distance of the center of gravity of the balance weight is set in accordance with both the stroke of the returning operation of the rear curtain group and the stroke of the running operation of the front curtain group. Therefore, it is possible to effectively cancel the vibration generated by both operations. Further, according to another embodiment, it is possible to further adjust the stroke distribution of both operations.

The present invention has been described with reference to the embodiments.
According to the technical idea of the present invention, various modifications are possible. For example, in the above-described embodiments, the masses of the front curtain group and the rear curtain group are almost equal, and the strokes thereof are different. However, the stroke of the return operation of the rear curtain group and the traveling operation of the front curtain group are described. The present invention can be applied to the case where the strokes are the same and the masses of the front curtain group and the rear curtain group are different. Furthermore, by setting the stroke difference and the mass difference between the front curtain group and the rear curtain group together, the setting can be made so that the anti-vibration effect by moving the center of gravity is optimized.

[0050]

As described above, according to the present invention, the stroke of the balancer means is different between the case where the stroke is interlocked with the return operation of the rear curtain group and the case where it is interlocked with the running operation of the front curtain group. By varying the stroke of the balancer means in accordance with the difference between the moving moment of the return operation of the rear curtain group and the moving moment of the traveling operation of the front curtain group, the vibration caused by the traveling of the rear curtain group and the front curtain group is maximized. It is possible to prevent it as much as possible.

[Brief description of the drawings]

FIG. 1 is a plan view and a side view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 2 is a plan view and a side view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 3 is a plan view and a side view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 4 is a plan view and a side view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 5 is a front view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 6 is a front view showing a first embodiment of a vibration isolator of a focal plane shutter according to the present invention.

FIG. 7 is a front view showing a second embodiment of the vibration isolator of the focal plane shutter according to the present invention.

FIG. 8 is a front view showing a second embodiment of the vibration isolator of the focal plane shutter according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 board 2 cover plate 3 front curtain group drive lever 5 front curtain group pin 9 spring 10 pin 11 brake lever 12 axis 13 front curtain group brake stopper 14 rear curtain group drive lever 15 axis 18 axis 19 spring 20 pin 21 rear curtain group lever 22 Rear Curtain Group Pin 24 Brake Lever 25 Axis 26 Rear Curtain Group Brake Stopper 27 Balancer Lever 29 Axis 30 Balancer Return Lever 31 Balancer Travel Lever 32 Connecting Pin 33 Axis 36 Balancer Travel Lock Lever 38 Spring 39 Pin 40 Return Lock Lever 42 Spring 43 Pin 44 Balancer return stopper 45 Balancer travel stopper 46 Front curtain group 47 Rear curtain group

Claims (3)

(57) [Claims] An exposure starts when the rear curtain group returns to a start position in order to release the double light shielding state from a state where the photographing screen is double-shielded, and then the front curtain group starts running. In a vibration isolator for a focal plane shutter configured to end exposure by running the rear curtain group after a predetermined time has elapsed from the start of traveling of the front curtain group, a return mechanism of the rear curtain group, A balancer unit including a balance weight, wherein the balancer unit reciprocates in conjunction with the return operation of the rear curtain group and the traveling operation of the front curtain group, and the stroke of the balancer unit is An anti-vibration device for a focal plane shutter, which is different in a case where it is interlocked with a return operation of the rear curtain group and in a case where it is interlocked with a running operation of the front curtain group. 2. A stroke of the balancer means in conjunction with a return operation of the rear curtain group is shorter than a stroke of the balancer means in conjunction with a travel operation of the front curtain group. Item 2. An anti-vibration device for a focal plane shutter according to item 1. 3. The balancer means is a balancer lever reciprocatingly swinging in a return operation direction of the rear curtain group and in a traveling operation direction of the front curtain group, and the swing stroke of the balancer lever is adjusted by the rear curtain. 2. The vibration isolator of the focal plane shutter according to claim 1, wherein a case where the operation is linked with a group return operation and a case where the group is linked with a traveling operation of the front curtain group are different.