JPH0339775Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an aperture device for a camera, and in particular, when the aperture drive member is moved forward by the shutter release operation, the aperture mechanism, which is initially in the open position, is moved in the narrowing direction. The present invention relates to an automatic aperture device which is configured to prevent the above operation and determine the aperture value by electrical control when the aperture value reaches an appropriate value.

It is an object of the present invention to provide such an automatic diaphragm device with the ability to prevent the diaphragm operation immediately after the start of the diaphragm operation in order to deal with cases where the brightness of the field is low, and to position the diaphragm mechanism at the open position after exposure is completed. An object of the present invention is to provide a new and simple configuration that can simultaneously solve the two problems of smoothly returning to the system.

The present invention will be explained below with reference to drawings showing an embodiment of the present invention implemented in a single-lens reflex camera.

Fig. 1 is a plan view of a single-lens reflex camera in which the present invention is implemented, in which 1 is the camera body, 2 is the photographing lens system, 3 is the right side wall of the mirror box, and M ₁
is a diaphragm mechanism provided on the outer surface of the right side wall of the mirror box, and _M2 is provided in a direction perpendicular to the diaphragm mechanism _M1 , and is operationally related to this (as will be described later). This is an aperture adjustment mechanism.

FIG. 2 shows the aperture stop mechanism _M1 viewed from the direction of arrow A in FIG. 1 in a state where the camera release button (not shown) has not been pressed (inactive state). 4 is connected to the wall surface 3 by the shaft 5.
With the set lever pivoted on the top, the two arms 4a,
4b, and a fixing pin 4c.

The set lever is biased counterclockwise by a spring 6, and the tip of the arm 4a is pressed against a set pin 7.
It is in pressure contact with the Directly or indirectly related to the operation of the camera's release button, the set pin 7 moves forward a certain distance in the direction of the arrow from the position shown in the figure as a starting point, and then reverses and moves back in response to the shutter closing signal. It is designed to stop at a certain position. Reference numeral 8 denotes an aperture lever pivotally supported on the wall surface 3 by a shaft 9, which has an upright portion 8a and a spring hook (pin) 8b.
and a connecting pin 8c. The spring 10 biases the aperture lever 8 in a counterclockwise direction.

Reference numeral 11 denotes an aperture opening lever pivotally supported on the shaft 9, which includes a bent portion 11a and two arms 11b and 11.
It has c. A spring 12 stronger than the spring 10 is stretched between the arm 11c of the aperture opening lever and the aperture lever 8.

Reference numeral 13 designates a stopper for regulating the clockwise rotation position of the aperture lever 8, and reference numeral 14 designates an operating stick for the aperture ring which is biased in the direction of the arrow by a spring (not shown). The spring biases the aperture blades (not shown) in the direction of closing. Further, the lower limit position of the aperture control rod 14 changes because the maximum aperture value changes depending on the interchangeable lens loaded in the camera, but in this embodiment, when a lens with the maximum usable aperture value is used. It shows.

In the illustrated unactuated state, the diaphragm is fully open in the above sense, and the spring 10
and 12 tensions, the aperture opening lever becomes
The arm 11a is brought into pressure contact with the pin 4c of the set lever, and the aperture lever 8 is brought into pressure contact with the aperture operating rod 14. At this time, there is a gap d between the aperture lever 8 and the bent portion 11a of the aperture release lever (the size of which changes as the position of the aperture operating rod 14 changes), and the aperture ring The operating rod 14 is moved by the tension of the spring 12 to the vertical portion 8 of the aperture lever 8.
It is in pressure contact with a.

FIG. 3 shows the diaphragm adjustment mechanism M ₂ in the same state as in FIG.
It is a figure seen from the direction of.

Reference numeral 21 denotes a fan-shaped gear pivotally supported on a fixed part (not shown) by a shaft 22, which is connected to the connecting pin 8c of the aperture lever 8.
It has two prongs 21a that sandwich the two. (The aperture lever 8 and the sector gear 21 are always connected.) A first gear 23 is designed to mesh with the sector gear 21, and has a brush (not shown) fixed to its back surface.

As the sector gear 21 rotates, the brush slides on a resistor provided on the fixed part behind the sector gear 21.

25 is a ratchet gear. The ratchet gear connects to the sector gear 23 via a connecting gear 24.
It is connected to and rotates in conjunction with this. 26 is an electromagnet provided in the fixed part. The electromagnet is controlled by a control circuit (not shown) that includes the brush and a variable resistor consisting of a resistor.

Reference numeral 27 denotes a locking lever that is pivotally supported on the fixed portion by a shaft 27a, and has an engaging portion 27b and two vertically bent portions 27c ₁ and 27c ₂ .

Reference numeral 28 denotes a pawl lever pivotally supported on the locking lever 27 by a shaft 28a, which is connected to the ratchet gear 25.
It has a pawl 28b ₁ and an upright part 28b ₂ formed as an upright bent part to prevent the clockwise rotation. The pawl lever 28 is biased counterclockwise by a weak spring 28c, and is normally in pressure contact with the upright portion _27c1 . Reference numeral 29 denotes an iron piece provided on the locking lever 27 so as to face the electromagnet. 30 is a spring that biases the locking lever 27 in a counterclockwise direction. A release lever 31 is pivotally supported on the fixing part by the shaft 27a, and has a vertically bent part 31a that comes into contact with the set lever 4.
A spring 32 stronger than the spring 30 is stretched between the release lever 31 and the locking lever 27. Reference numeral 33 denotes a stopper that restricts the left rotation position of the locking lever 27.

As shown in the figure, in the non-actuated state, the release lever 31 is pushed down by the arm 4b of the set lever, and a gap d' is created between the engagement portion 27b of the locking lever 27 and the release lever 31. , spring 3
Since the tension of the spring 32 is greater than that of the spring 32, the pawl lever 28 on the locking lever 27 is in a position where it does not engage with the ratchet gear 25.

Next, the movements of the above-mentioned parts in the operating state will be explained.

In FIG. 2, when the release button of the camera is operated as described above, the set pin 7 starts moving in the direction of the arrow, and the set lever 4 starts turning left as the set pin 7 moves.

At the same time, the electromagnet 26 is excited by the control circuit described above, so that the iron piece 29 is attracted and held.

In FIG. 3, the counterclockwise rotation of the set lever 4 in FIG. It rotates to the left about the shaft 27a so that the gap d' existing between it and the locking lever 27 disappears.

The movement of the release lever 31 stops when this distance d' disappears, and the arm 4b of the set lever 4 moves further away from the vertically bent portion 31a of the release lever 31.

In this way, since the iron piece 29 provided on the locking lever 27 is attracted by the electromagnet 26, the spring 30 is charged with a restoring force.

That is, the locking lever 27 is rotated in the counterclockwise direction (ratchet gear 2
This means that the device is waiting for the holding by the electromagnet 26 to be released while a biasing force is applied in the direction in which the device 5 is locked.

When the electromagnet 26 is demagnetized by the control circuit, the attraction of the iron piece 29 is released, and the locking lever 27 is moved by the spring 3.
Immediately start left rotation with zero return force.

The pawl lever 28 enters a position in which it can lock the ratchet gear 25 by turning the locking lever 27 to the left. In addition, in parallel with the above, the gap d between the aperture lever 8 and the aperture opening lever 11 in FIG. The release lever 11 is integrally rotated to the left by the tension of the spring 10. Due to this left rotation, the upright portion 8a of the aperture lever moves to the second position.
Since it moves upward in the figure, the operating rod 14 moves integrally following the upright portion, and the aperture blades close.

The movement of the aperture lever 8 and therefore the connecting pin 8c rotates the first gear 23 via the sector gear 21, thereby causing the brush to slide on the resistor. That is, the aperture diameter and the change in the resistance value of the variable resistor correspond to each other in a 1:1 ratio. When the resistance value reaches a predetermined value (this predetermined value may be set in advance by the photographer or automatically determined according to the brightness of the subject),
The aperture lever 8, which is interlocked with the fan-shaped gear 21, has moved in a predetermined range according to the aperture corresponding to the predetermined value, and the control circuit de-energizes the electromagnet 26, and the locking lever 27 is released. spring 30
Turn left until it is stopped by stopper 33,
The pawl _28b1 of the pawl lever 28 locks the ratchet gear 25 from turning to the right. (Fig. 4) With the above locking, each gear and lever 8 and 1
1. The aperture operating rod 14 stops and the aperture diameter is determined, but as the set pin 7 moves, the set lever 4
continues to rotate to the left, and at the end of the left rotation, its arm 4b
reaches a little further above the fourth illustrated position. (FIG. 5) During this time, the pawl lever 28 remains locked to the ratchet gear 25. Normally, the mirror rises at the same time as the diaphragm blades finish narrowing down, and immediately after that, the shutter blades begin to open.

Further, when the shutter blade closes, the set pin 7 moves in the opposite direction in response to the signal received by a mechanism (not shown). As a result of this movement, the set lever 4 rotates to the right, and the arm 11b is pushed by the pin 4c, causing the aperture release lever 11 to rotate to the right, and the aperture lever 8, which is connected to it by a spring 12, to rotate to the right, and at the same time, the aperture release lever 11 rotates to the right. The operating rod 14 is pushed in the opposite direction to open the aperture blades.

The right rotation of the aperture lever 8 in FIG. 5 results in a downward movement in FIG. 4.

When the aperture lever 8 starts moving downward, the sector gear 21 rotates to the right, the gear 23 rotates to the left, the gear 24 rotates to the right, and the ratchet gear 25 pushes the claw lever 28 against the biasing force of the spring 28c. Therefore, the movement of the aperture lever 8 is stable and smooth from the beginning of operation.

The force required for this operation is small because the force of the spring 28c is extremely weak.

Near the end of the clockwise rotation of the set lever 4, that is, near the point at which the clockwise rotation of the aperture lever 8 is stopped by the aperture operating rod 14, which stops at its lower limit position (i.e., the opening of the aperture blades ends). The arm 4b abuts against the vertically bent portion 31a of the release lever 31. Then, in the process of further turning the set lever 4 to the right, the locking lever 27 is turned to the right via the release lever 31, and when the set pin 7 returns to its original position, the iron piece 29 comes into contact with the electromagnet 26, and the locking lever 27 is turned to the right by the release lever 31. Lever 2
8 reaches a position where it cannot mesh with the ratchet gear 25, and one aperture driving operation is completed.

As explained above, the automatic aperture mechanism of the present invention can lock the ratchet gear 25 immediately after the set lever 4 starts moving, so it has the advantage of being able to set aperture values in a wide range including wide open aperture. Since the ratchet gear 25 can be smoothly reversed even in the locked state, it does not require a large force to return the aperture lever to its original position after exposure, and it does not require much force to return the aperture lever to its original position after exposure. The mechanism is simple and the safety of the series of operations can be easily ensured.

It goes without saying that the technical scope of the present invention is not limited to the embodiments.

For example, the aperture lever 8 and the aperture release lever 11
can be used as a single lever if the maximum aperture of the aperture does not differ depending on the photographic lens system, and the spring 10 can also serve as the aforementioned spring (not shown) that biases the aperture operating rod 14. This is also optional.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the schematic arrangement when the present invention is implemented in a single-lens reflex camera, Fig. 2 is a front view of the aperture mechanism M1 in the embodiment shown in Fig. ₁ in an inoperative state, and Fig. 3 is a front view of the diaphragm adjustment mechanism M ₂ in the embodiment shown in FIG. 1 in an inoperative state; FIG. 4 is an explanatory view showing the diaphragm adjustment mechanism M ₂ in a locked state;
FIG. 5 is a front view of the diaphragm mechanism _M1 after its operation. 1...Camera body, 2...Photography lens system, 3
...Right side wall of the mirror box, M ₁ (4 to 1 below)
4) ... Refinement mechanism, M ₂ (21 to 36 below)
...Aperture adjustment mechanism, 4...Set lever (aperture drive member), 5...Shaft, 6...Spring, 7...Set pin (aperture drive member), 8...Aperture lever (aperture regulation member), 9... Shaft, 10... Spring, 11...
Aperture opening lever, 12...Spring, 13...Stopper, 14...Aperture operating rod, 21...Sector gear (connecting member), 22...Shaft, 23...First gear, 2
4... Connection gear, 25... Ratchet gear (locked member), 26... Electromagnet (holding means), 27...
Locking lever (locking member), 27a...shaft, 27c ₁ ,
27c ₂ ... Vertical bent portion, 28 ... Claw lever (locking member), 28a ... Shaft, 28b ₁ ... Claw, 28b ₂ ...
Vertical part, 28c... Spring, 29... Iron piece, 30...
... Spring, 31 ... Release lever (release member), 32
……Spring.

Claims (1)

[Scope of Claim for Utility Model Registration] An aperture drive member 4 that reciprocates in a predetermined range in relation to the release operation of a camera release button, an aperture regulation member 8 that reciprocates within a predetermined movement range, and the aperture regulation member 8 A diaphragm operating member 14 that moves following the diaphragm control member 8, a locked member 25 that is configured to interlock with the diaphragm regulating member 8 via a gear train, and a biasing member 30 that moves the locked member 25 in the locking direction. energized locking members 27, 28; holding means 26 for holding the locking members 27, 28 against the urging force of the urging member 30;
The camera aperture mechanism has a release member 31 configured to displace and hold the locking member 8 against the urging force of the urging member 30, and the locked member 25 is a ratchet gear. In addition, the locking members 27 and 28 are connected to the release member 31.
The locking lever 27 connected to the locking lever 2
The locking members 27 and 28 are held by the holding means 26 with the release operation and are biased by the forward movement of the aperture drive member 4 during the narrowing operation. 30 is in a charged release standby state, and when the holding by the holding means 26 is released, the urging member 30 immediately moves to lock the locked member 25, and the aperture opening operation is performed. At this time, when the aperture regulating member 8 moves back, the ratchet gear 25 via the gear train moves the aperture drive member 4 to the release member 31 from the beginning of the operation.
The aperture mechanism is characterized in that the pawl lever 28 is rotated while being pushed until the locking lever 27 is displaced through the diaphragm mechanism.