JPS6233577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aperture auxiliary brake in an aperture control automatic exposure camera.

Conventionally proposed aperture apertures that actually reduce the aperture of the lens from its open state and measure the light rays of the subject that have passed through the aperture of the aperture to make the aperture appropriate for the predetermined shutter speed and film sensitivity. In an aperture-controlled auto-exposure camera that stops the aperture operation and automatically determines the aperture opening when the aperture is narrowed down to Since it is too short to lock accurately, the slow speed mechanism is linked to an operating member that operates in conjunction with the throttle operation.

However, if a slow speed mechanism is installed that slows down the aperture of the lens to the extent that it can be controlled with sufficient precision, the operation time will be longer if the aperture must be stopped down to a value close to the minimum aperture in order to obtain proper exposure. This results in a longer time from release to shutter operation, resulting in a delay in shutter start. Therefore, if the effectiveness of the slow speed mechanism is weakened to cause the lens to stop down quickly, it will be difficult to stop the aperture accurately.

In view of the above points, the present invention aims to provide a mechanism that can control the diaphragm with high precision despite the short total operating time.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the structure of the aperture value control mechanism, auxiliary brake mechanism, and front curtain release device before winding. First, the winding operation will be explained.

A cam of a winding mechanism (not shown) and a charge pin 2 are in contact with the charge lever 1, and when the winding operation is performed, the charge lever 1 rotates to the right, and a fork-shaped lever 3 rotatably provided on the charge lever 1 moves the pin 4.
When the set lever 5 is rotated clockwise against the spring 6 through Rotate to the left against the spring 10. Therefore, the armature 11 pivotally mounted on the lever 9 comes into contact with the iron core 12 of the aperture control magnet 34 fixed to the camera body.

Further, the control lever 14 which is spring-coupled to the lever 9 by the spring 13 also rotates to the left, and the locking portion 14
A is removed from the star wheel 33 at the final stage of the slowing mechanism.

Furthermore, with the displacement of one end 9a of the operating lever 9,
The leading curtain locking lever 16 is rotated to the right by the spring 17 via the relay lever 15, and is on standby in a state where it can be engaged with the leading curtain locking cam 18.

Similarly, by means of a pin 41 implanted in a lever (not shown) that engages with the set assisting lever 8,
The pallet lever 38 rotates to the right against the spring 39, and the armature 37 pivotally connected to the pallet lever 38 comes into contact with the iron core 35 of the auxiliary brake magnet 36, causing the pallet arm 40 to retreat from the star wheel. With the iron cores 12 and 35 in contact with each other, the set auxiliary lever 8 and the locking lever 7
is engaged and the set lever 5 is locked. At this time, so that the rotational displacement of the charge lever 1 is maximum,
Of course, the winding cam is set,
The winding cam is set so that the charge lever 1 returns to the left in subsequent winding operations.
Therefore, the fork-shaped lever 3 returns leaving the pin 4 behind.

On the other hand, the winding operation rotates the upper speed change gear 19 that meshes with a gear of a winding mechanism (not shown), and the leading curtain pinion 20 that meshes with this rotates the leading curtain 22 via the pulling body 21 and charges it.

Further, the gear 24 is rotated by a pin 23 implanted in the gear 19 and a pin 25 implanted in the lower transmission gear 24, and the trailing curtain 27 is wound up and charged by the trailing curtain pinion 26.

Further, when the winding is completed, the leading curtain locking cam 18, which is integrally connected to the upper transmission gear 19, is positioned so as to engage with the leading curtain locking lever 16, so that the leading curtain locking cam 18 is locked when the winding is completed. Ru.

Next, the mirror box mechanism will be explained.

In Fig. 1, the charge lever 1 rotates to the right due to the winding operation, but at this time the pin 4 engaged with one end 1a
4 is fixed to the drive lever 45 (second
), therefore, the lever 45 has a restoring spring 48
It rotates to the right while accumulating energy in the mirror raising spring 46, and the locking portion 45a and the second locking lever 47 engage to complete charging. A force that imparts dextrorotation to the first actuating lever 42 through the mirror raising spring 46 by turning the drive lever 45 to the right, and displacing one end 43a of the second actuating lever 43 to the right in FIG. 3 by the one end 42a. works.

However, in FIG. 3, the lever 43 is locked by the vertically bent portion 57a of the first locking lever 57, and the mirror lifting spring 46 is loaded.

On the other hand, the aperture release plate 61 of the lens is always biased in the aperture direction, that is, upward in FIG. It is held down by the vertically bent portion 60a of the lever 60. This restoration lever 60 is connected to the coupling spring 50.
is connected to the lever 51 by the lever 5.
The first vertically bent portion 51a is locked by a third locking lever 52.

Next, the structure of the slow speed mechanism will be explained.

In FIG. 1, the coupling pin 28 operates in conjunction with the aperture release plate on the lens side (61 in FIG. 3) and the slide plate 59, and engages with the long groove 29a of the fan-shaped gear 29. The sector gear 29 meshes with the first pinion gear 30, the spur gear 31, and the second pinion gear 3.
The purpose of this slow speed mechanism is to increase the operating position of the aperture release plate 61 and improve control accuracy.
The aim is to improve durability by reducing the locking force.

Opposed to the star wheel 33 at the end of the gear train is the aforementioned pallet wheel 40.

Further, a one-way clutch is provided between the first pinion gear 30 and the spur gear 31, and when the coupling pin 28 in FIG. 1 moves upward, the first pinion gear 30 and the spur gear 31 become integral. Control is performed by rotating the star wheel 33, and when the star wheel 33 is locked, the connecting pin 28 can return downward to restore the aperture to its open state. Here we will explain the operation from the release of the camera. In conjunction with pressing down the release button (not shown),
The release lever 53 operates downward in FIG. 3, and the first locking lever 57 therefore rotates to the right and disengages from the second operating lever 43. Thereupon, the first operating lever 42 is rotated to the right in FIG. 2 by the mirror raising spring 46, and the second operating lever 43 is rotated to the left in FIG. 3. Next, the cam portion 5 of the mirror lifting lever 54 is moved by the pin 58 fixed to the second operating lever 43.
4a and rotates the lever 54 to the right, which engages with a gear provided at the tip, rotates the mirror raising gear 55 to the left, and raises a mirror (not shown). Second
At the end of the operation of the operating lever 43, that is, at the end of the mirror rising, the third locking lever 52 is kicked by the vertically bent portion 43b to rotate to the right, and the locking of the lever 51 is released.

The lever 51 and the restoring lever 60 are connected to the spring 5
6 causes an instant left turn. Then, restore lever 6
The slide plate 59, which had been held at 0, begins to move upward, the aperture of the lens begins to narrow down, and as the coupling pin 28 operates, the slow speed mechanism shown in FIG. 1 also begins to operate. do.

On the other hand, in FIG. 1, the set lever 5 is locked by the locking lever 7 due to the winding operation;
When the first operating lever 42 of the mirror box mechanism is rotated by the camera release, the vertically bent portion 42b of the lever 42 kicks one end 7a of the locking lever 7.

The set lever 5 instantly returns to the left rotation by the spring 6, and the operating lever 9 and ankle lever 38
attempts to rotate, but at this time the aperture control magnet 34 and the auxiliary brake magnet 36 are energized, the armatures 11 and 37 are attracted, and the operating lever 9 and ankle lever 38 are prevented from rotating.

Here, a configuration for controlling the aperture value in response to a change in the amount of incident light due to aperture will be described below.

The viewfinder observation mirror has already been raised, and the light-receiving element 63 is installed at the bottom of the mirror box outside the shooting incident optical path as shown in FIG.
The photographing lens side of the camera is subjected to reflection treatment, and is configured to capture the reflected light.

Further, a block diagram of the control circuit is shown in FIG.

The apex calculation B _V - A _V is optically performed using the subject brightness and the light amount change due to aperture, and the set film sensitivity S _V value is added to calculate the shutter speed T _V = S _V + B _V - A _V. Perform calculations.

This T _V value changes moment by moment according to B _V - A _V which changes as the aperture progresses, and compares it with the T _V value of the manually adjusted shutter speed set in advance by the comparison circuit B.
At the same time, comparison circuit A uses a level shift to compare the shutter speed with a value shifted from the manually adjusted shutter speed by a certain set value.

Here, the level shift is set to shift to a faster shutter speed than the manually adjusted shutter speed. Therefore, when the _TV value calculated by the _TV calculation circuit, which changes every moment as the aperture changes, and the _TV value shifted from the set _TV value first match in the comparison circuit A, the control circuit A The auxiliary brake magnet 36 is de-energized through the auxiliary brake magnet 36. As a result, the adhesion between the iron core 35 and the armature arm 37 is released, the pallet lever 38 is rotated to the left by the spring 39, the pallet lever 40 is applied to the star wheel 33, an auxiliary brake is applied, and the displacement of the aperture blades is slowed down, and the aperture is further narrowed down. The calculated T _V value and the set T _V value match in comparison circuit B.

When the two match, the iris control magnet 34 is de-energized through the control circuit B. As a result, the lock 12 and the armature 11 are released from adhesion, and the operating lever 9 is rotated to the right by the spring 10. The spring-coupled control lever 14 also rotates to the right, engages the star wheel 33 of the slowing mechanism, connects the coupling pin 28, and slides the slide plate 5.
9, the operation of the aperture release plate 61 of the lens is stopped, and the aperture is stopped at an appropriate value.

The actuating lever 9 further turns to the right, kicks the relay lever 15 with one end 9a, releases the leading curtain locking lever 16 and the leading curtain locking cam 18, and the leading curtain 22 starts running. After a time period set by an exposure time adjustment mechanism (not shown) has elapsed, the trailing curtain 27 runs. At the end of the travel of the trailing curtain, the pin 47a fixed to the second locking lever 47 in FIG. The drive lever 45 is then returned by the restoring spring 48, and the second operating lever 43 is restored. In FIG. 3, the protrusion 43c of the second operating lever 43
The bent portion 51b of the lever 51 is pushed to restore the restoring lever 60 via the coupling spring 50. Accordingly, by returning the slide plate 59, the aperture of the lens also returns to its open state. At this point, the slowing mechanism is locked, but since the one-way clutch is located between the first pinion gear 30 and spur gear 31 as described above, the slide plate can be restored.

Further, the mirror lifting lever 54 is also restored by the spring 56, and the mirror is restored to its original state. The lever 51 and the third locking lever 52 are engaged, and all operations are completed.

FIGS. 6 and 7 are graphs of the above-described aperture control operation in which changes in the amount of light from the light-receiving element 63 are converted into an aperture value, and the relationship with time. As an example, assume that a lens from F1.4 to F22 is used, and that the auxiliary brake is applied 1 EV before.

Figure 6 shows A when a light slowing mechanism is used to shorten the total running time when there is no auxiliary brake.
(total running time 24 mS) and B (total running time 160 mS) when the total running time is lengthened to improve accuracy.

Generally, the amount of movement per 1 EV of the aperture release plate of a lens is smaller near the minimum aperture than near the maximum aperture. Therefore, even if the aperture release plate of the lens is moved at approximately constant speed, the amount of light changes rapidly near the minimum aperture. In this example, A takes 1.5 mS from F16 to F22. If the aperture control magnet 34 were to fluctuate by 2 mS, it would become impossible to control the aperture. Therefore, in B, where the total running time was lengthened to improve accuracy, the time from F16 to F22 is 12mS. Here, even if the aperture control magnet varies by 2mS, the error is 1/6
(0.17) It is only EV.

However, if around f/22 is appropriate, control time is added to the normal delay time from the release of a single-lens reflex camera until the shutter starts operating, resulting in a considerable delay time.

On the other hand, FIG. 7 is a graph of a slow speed mechanism with an auxiliary brake according to the present invention.

Total driving time when operated without auxiliary brake
20 mS (curve A). As an example, curve C is where F8 is appropriate and the auxiliary brake is applied at F5.6, 1 EV earlier. As you can see from this graph,
The auxiliary brake is applied at F5.6, and the aperture diameter changes slowly, and the lens travels from F5.6 to F8 in 12.5mS. Here, even when the locking magnet fluctuates by 2 mS, even though the fluctuation is only 2/12.5 (0.16) EV, even when the F22 is appropriate, as shown in curve B, even if the auxiliary brake is engaged before 1 EV, it will vary by 30 mS.
The operation has been completed.

As described above, in the present invention, when the proper exposure is achieved, before stopping the aperture operation,
Since the auxiliary brake is applied by cutting off the power to the auxiliary brake magnet 36 as early as a certain set value, the aperture can be controlled with high precision even though the total operating time is short, which is very effective.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the aperture control and leading curtain locking section of the present invention. Figure 2 is a perspective view of the lower part and mirror box mechanism.
FIG. 3 is a perspective view of the side mirror box mechanism. FIG. 4 is a sectional view showing the arrangement of light receiving elements. FIG. 5 is a block diagram of the circuit configuration. Figure 6 shows the relationship between aperture and time when there is no auxiliary brake. Figure 7 shows the relationship between aperture and time when the auxiliary brake is attached. 1: Charge lever, 1a: One end of charge lever, 2: Charge pin, 3: Lever, 4: Pin, 5: Set lever, 6: Spring, 7: Locking lever, 8: Set auxiliary lever, 9: Operating lever, 10: Spring , 11: Amarch Your,
12: Iron core, 13: Spring, 14: Control lever, 15: Relay lever, 16: Leading curtain locking lever,
17: Spring, 18: Leading curtain locking cam, 19:
Shift gear upper, 20: Leading curtain pinion, 21: Traction body, 22: Leading curtain, 23: Pin, 24: Lower shifting gear, 25: Pin, 26: Trailing curtain pinion, 27: Trailing curtain, 28: Connection pin, 29: sector gear, 30: first pinion gear, 31: spur gear, 32: second pinion gear, 33: star wheel, 34: aperture control magnet, 35: iron core, 36: auxiliary brake magnet, 37: armature, 38: Ankle lever, 39: Spring, 40: Ankle, 41:
Pin, 42: First operating lever, 43: Second operating lever, 44: Pin, 45: Drive lever, 46: Mirror lifting spring, 47: Second locking lever, 4
8: Restoration spring, 50: Combination spring, 5
1: Lever, 52: Third locking lever, 53: Release lever, 54: Mirror lifting lever, 55: Mirror lifting gear, 56: Spring, 57: First locking lever, 58: Pin, 59: Slide plate, 6
0: Restoration lever, 61: Aperture release plate, 62:
Restoration spring, 63: Light receiving element, 64: Film.

Claims (1)

[Scope of Claims] 1. The film sensitivity is determined based on the optical calculation result of the aperture linking member that operates in conjunction with the change in the aperture diameter due to the stop-down, and the light reflected from the subject and the aperture that changes as the stop-down progresses. The first step is to compare the shutter speed obtained as a result of the apex calculation with the manually adjusted shutter speed set in advance, and to operate the aperture control magnet when the two match. In an automatic exposure camera comprising a control circuit and a mechanism that stops the aperture linking member and performs appropriate aperture value control through the operation of the aperture control magnet, the aperture linking member decelerates the movement of the aperture linking member to slow down the aperture operation. a brake magnet mechanism that operates the slow speed mechanism by operating an auxiliary brake magnet, and a shutter that is shifted by a certain amount to a side faster than a preset manually adjusted shutter speed. A second control circuit is provided which compares the speed and the shutter speed as the calculation result and operates the auxiliary brake magnet when the two match, so that the aperture can be adjusted appropriately regardless of the amount of change in the aperture diameter. The auxiliary brake magnet is activated to slow down the aperture operation approximately a certain period of time before the shutter speed reaches the specified value, and then the aperture is activated when the preset manually adjusted shutter speed matches the calculated shutter speed. An aperture auxiliary brake device for an automatic exposure camera with aperture value control, characterized by activating a control magnet to stop an aperture operation.