JPH06102560A - Shutter for camera - Google Patents

Abstract

PURPOSE:To provide an automatic high-speed shutter even in a large aperture by making opening/closing shutter blades thinner. CONSTITUTION:A first motor 3 and opening shutter blades 4 and 5 opened to start an exposure are provided on one side of an exposing aperture 2. A second motor 9 and closing shutter blades 10 and 11 closed to compete the exposure are provided in a position opposite to the first motor 3 with interposed the aperture 2. The inside edge parts of each shutter blade are linearly formed. In the opening shutter blades 4 and 5 at a closing position, the width of an overlapping region is wider than that of the closing shutter blades 10 and 11 and a shape is larger as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter, and more particularly to a shutter used for a camera having a large aperture diameter.

[0002]

2. Description of the Related Art Conventionally, in general small cameras and the like,
There is known a shutter in which a single pulse motor is used as a force source and the motor is reciprocally driven to open / close the shutter blades. On the other hand, in a so-called large format camera, since the size of the lens is large, the diameter of the lens is large and the aperture diameter of the optical path is large. In such a shutter of a camera having a large optical path diameter, since the traveling distance of the shutter blades is large, it is necessary to increase the traveling speed of the blades, and a powerful spring is provided as a driving force source for the shutter blades manually. I was charging. Since such manual charging is performed against a strong spring, the amount of charging power is large and heavy. By the way, in this type of shutter, the elastic force of the spring is stronger than the driving force of a small motor that can be mounted on the shutter. Therefore, if the motor automatically charges the shutter blades, a large amount of power is required for the motor, resulting in a problem that the outer shape of the motor becomes large.

[0003]

Further, even in a shutter having a large aperture for exposure of a camera such as a shutter of a large format camera, a chargeless shutter device is desired because of simplification of operation. became. In such a case, if a chargeless shutter is used in which a single motor is used as a driving force source such as a large format camera and the above-mentioned small camera to open and close the shutter blades, the drive is performed as described above. Since it is difficult to increase the size of the motor that serves as the power source, and the driving force of the motor is weak in the end, the shutter speed becomes slow and a high speed cannot be obtained. Particularly, in the vicinity of the fully opened position of the shutter blades, the motor and the shutter blades are reciprocally switched, so that the speeds of the motor and the shutter blades are remarkably reduced due to inertia and the like. There was a problem of becoming. Therefore, it is difficult to configure the shutter as a chargeless type in a large format camera or the like.

In view of the above problems, it is an object of the present invention to provide a chargeless type camera shutter that can obtain a high shutter speed even in a shutter having a large diameter opening for exposure. To do.

[0005]

A camera shutter according to the present invention comprises an exposure opening, an opening shutter blade for opening the exposure opening, and a closing shutter blade for closing the exposure opening. A first motor for operating the opening shutter blades and a second motor for operating the closing shutter blades are provided. Further, in the camera shutter according to the present invention, the first and second motors are attached at positions substantially facing each other with the exposure opening interposed therebetween. The camera shutter according to the present invention has an opening shutter blade that is opened to start exposure and a closing shutter blade that is closed to end exposure, and the opening shutter blade is closed. It is characterized in that the area and the overlapping width between the blades in the closed state are larger than those of the shutter blades for use. Further, in the camera shutter according to the present invention, the inner edge portions of the opening shutter blade and the closing shutter blade are each formed in a linear shape. Also, the closing shutter blade and the opening shutter blade do not necessarily have to have the same plate thickness, and for example, the closing blade may have a smaller plate thickness than the opening blade.

[0006]

In the exposure control, the exposure is started by driving the first motor to open the opening shutter blade that is in the closed state with respect to the exposure opening, and the exposure is started after the required exposure time elapses. The exposure is completed by driving the motor of (1) to close the shutter blade for closing. The closing shutter blade has a relatively small shape, and the overlapping amount between the blades in the closed state is not large, but there is no risk of light leakage when both the opening and closing shutter blades are in the closed state. In addition, since the opening shutter blades have a large overlap between the blades, the opening shutter blade has a sufficient running distance for reaching the pinhole position from the start position and starting the exposure when the opening operation is started. Therefore, the traveling speed of the blades can be accelerated, and the traveling speed of the shutter blades after the start of exposure can be made high, so that a high speed time can be obtained. Also, by forming the inner edges of both shutter blades in a straight line, the blades are overlapped without crossing without colliding due to the principle of scissors when operating in the closing direction, and close at high speed. To be done. Further, by reducing the thickness of the blade member, it is possible to reduce the weight of the blade and increase the opening / closing operation speed of the shutter blade.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. 1 is a plan view of the shutter before the start of exposure, FIG. 2 is a plan view of the shutter after the end of exposure, FIG. 3 is a timing chart of the shutter operation, and FIG. 4 is a view showing the relationship between the opening / closing operation of the shutter blades and the approach distance FIG. 5 is a flowchart showing a general sequence for shutter operation. In FIGS. 1 and 2, an exposure opening 2 is formed in the central portion of the shutter base plate 1. An iris motor (moving magnet type motor), that is, a first motor 3 is fixed to the back surface of one side of the opening 2 (the back side of the paper surface), and a drive pin 3a provided on the output shaft of the first motor 3 extends along the rotation range. Through the long hole 1a formed in the main plate 1 and protrudes to the front surface side of the main plate 1. A pair of opening shutter blades 4 and 5 are supported on the surface of the main plate 1 so as to be rotatable around support shafts 6 and 7, respectively, and are connected to the drive pin 3a by a pin-slot connection to form an opening 2. It can be opened and closed. The first motor 3 for driving the opening shutter blades 4 and 5 is arranged so as to be in the neutral position when the opening shutter blades 4 and 5 are in the closed position by using the auxiliary pole as a slicing iron piece. . The opening shutter blades 4 and 5 are formed with linear inner edge portions 4a and 5a whose opening areas can be set during exposure (see FIGS. 1 and 2). Therefore, at the time of the closing operation, the edges 4a and 5a intersect each other without colliding with each other by the principle of scissors and are superposed at high speed.
Further, in the closed position shown in FIG. 1, the blades 4 and 5 are arranged such that the overlapping amount (L) in the operating direction of the overlapped regions is larger than the overlapping amount (l) of the closing shutter blades described later. The shape and area are formed. For the sake of convenience, the overlapping widths L and l will be described as being on a line along the diameter passing through the center of the opening.

Further, another iris motor (moving magnet type motor), that is, a second motor 9 is fixed to the rear surface of the main plate 1 so as to face the first motor 3 with the opening 2 interposed therebetween, and the output thereof. The shaft 9a penetrates the elongated hole 1b of the main plate 1 and projects to the front surface side of the main plate 1. On the surface of the main plate 1, a pair of closing shutter blades 10 and 11 are provided on the support shafts 12 and 1, respectively.
It is rotatably supported about 3, and is opened and closed with respect to the opening 2 by being pin-slot connected to the output shaft 9a. The second motor 9 that drives the closing shutter blades 10 and 11 uses the closing shutter blades 10 and 11.
When it is in the fully open position, the auxiliary pole is arranged as a squeezed iron piece in its neutral position. Shutter blade for closing 1
Like the opening shutter blades 4 and 5, 0 and 11 have inner edges 10a and 11a formed in a straight line (see FIG. 1). The area of the closing shutter blades 10 and 11 is smaller than the area of the opening shutter blades 4 and 5. The overlapping width l of the closing shutter blades 10 and 11 when closed is smaller than the overlapping width L of the opening shutter blades 4 and 5, and the plate thickness is also the opening shutter blade 4.
It is formed thinner than 5. This is because the present embodiment is a so-called chargeless type that is always in an operable state, and therefore the opening blades 4 and 5 close the opening 2 before the start of exposure. Of course, the same overlapping width L≈l may be used as long as it can sufficiently shield light or is a non-chargeless type. The shutter exposure control is performed by opening the opening shutter blades 4 and 5 from the state shown in FIG. 1 in which the opening shutter blades 4 and 5 are in the closed position and the closing shutter blades 10 and 11 are in the fully open position. It is started by being done. Further, the closing shutter blades 10 and 11 are closed from the position where the opening and closing shutter blades 4, 5 and 10 and 11 are both opened (FIG. 2).
(See).

This embodiment is constructed as described above,
Next, the operation will be described based on the timing chart shown in FIG. First, in the state where the previous photographing is completed, the shutters are the opening shutter blades 4, 5 and the closing shutter blade 10,
Both 11 are in the closed position with respect to the opening 2. And
When the main switch is turned ON in preparation for the next shooting, the second motor 9 is operated and the output shaft 9a is turned counterclockwise, and in conjunction with this, the pair of closing shutter blades 10 and 11 are operated to be opened, and in the fully opened state, The state shown in 1 is obtained. Next, when the first motor 3 operates for exposure, the output shaft 3a rotates counterclockwise, and the opening shutter blades 4 and 5 start opening accordingly. Since the opening shutter blades 4 and 5 have a large overlapping width L of both blades 4 and 5 in the closed state, the approach distance a from the closed state to the pinhole is a.
(See FIG. 4) is relatively long, so that both blades 4 and 5 reach the pinhole in a sufficiently accelerated state and further start opening operation toward full opening. In this way, the opening operation of the opening shutter blades 4 and 5 starts the exposure.

When a desired exposure time obtained by the photometry of a photometry circuit (not shown) has elapsed, the output shaft 9a of the second motor 9 is rotated rightward from the open position, and the output shaft 9a is closed accordingly. The shutter blades 10 and 11 are started to close. When the closing shutter blades 10 and 11 start to close and the edges 10a and 11a of the blades 10 and 11 intersect, the edges 10a and 11a overlap from the vicinity of the support shaft, so that they do not collide with each other by the principle of scissors. They are superposed while intersecting, and reach the closed position shown in FIG. 2 at high speed. In this way, the exposure is completed. Also, the closing shutter blade 1
When 0 and 11 are closed from the fully open position, even if the opening angle is maximum, a sufficient space cannot be taken until the opening 2 is blocked, so that the approach distance b for acceleration can be small ( (See FIG. 4).
In contrast to the occurrence of such inconvenience, in the present embodiment, each of the blades 10 and 11 is formed in a lightweight shape by reducing the outer shape and reducing the thickness of the blade, so that the blades having a normal shape (running edge) Compared with the distance c), acceleration of blade travel can be achieved even with a short approach distance (see FIG. 4). After that, the closing blades 10 and 11 complete the closing operation of the opening 2 and after a lapse of a predetermined time, the first motor 3 is operated and the output shaft 3a is also turned to the right, and the opened shutter blades 4 and 5 are closed. become. Therefore, in the initial state at the time of the next photographing, the opening shutter blades 4, 5 and the closing shutter blades 10, 1
Since both of them are in the closed state, the closing shutter blade 1
Even if the blade shapes of 0 and 11 are small and the overlapping width is small, the problem of leakage light does not occur. FIG. 5 is a flow chart showing the order of driving the first and second motors 3 and 9 during the shutter operation described above.

As described above, in this embodiment, the opening operation for the exposure control is performed by the first motor 3 and the opening shutter blades 4 and 5, and the closing operation is performed by the second motor 9 and the closing shutter blade 10. , 11, it is possible to suppress the speed reduction caused by the influence of the inertia of the motor and the shutter blade during the reversing operation, to operate the blade at high speed, and to improve the shutter speed. Therefore, it can be sufficiently applied as a shutter of a large format camera having a large aperture diameter and large blades, and can be of course applied to a so-called compact camera. Also, the first and second motors 3,
Since 9 is provided at a position opposed to each other with the opening 2 in between, the arrangement space of the shutter rarely interferes with the arrangement of other shutter components. Therefore, despite the provision of the plurality of motors 3, 9 and the shutter blades 4, 5, 10, 11, it is possible to prevent the mechanism from becoming large. or,
Since the width of the overlapping region of the opening shutter blades 4 and 5 in the closed position is large, it is possible to sufficiently accelerate the speed of each blade 4 and 5 before reaching the pinhole when the opening shutter blades 4 and 5 are opened. The shutter speed can be increased. or,
The opening and closing shutter blades 4, 5, 10, 11 are
Since each of the inner edge portions 4a, 5a, 10a, 11a is formed in a straight line, no closing occurs between the pair of blades, and the closing operation can be performed at high speed. In this regard, in the conventional shutter blade, in order to prevent a collision due to biting, the inner edge portions are formed in a substantially V shape so that the tip portions overlap each other even in the fully opened state. With this configuration, the shutter blade can be downsized, and the moment of inertia can be reduced, which is advantageous. Furthermore, when the closing shutter blades 10 and 11 are closed at the end of exposure, since the blades 10 and 11 are formed to be small, thin, and lightweight, a sufficient run-up distance of the blades is obtained at the start of the closing operation. Even without it, the closing operation will be quicker,
It is possible to speed up the operation of the closing shutter blades 10 and 11.

Although the closing shutter blades 10 and 11 are made thinner than the opening shutter blades 4 and 5 in the above-described embodiment, the opening shutter blades 4 and 5 are opposite to this.
The plate thickness of may be thinner. Further, although the iris motor is used as the driving force source in the present embodiment, other types of motors may be used to control the driving so that the blades are opened and closed, respectively.

[0013]

As described above, in the camera shutter according to the present invention, the opening shutter blade and the closing shutter blade are actuated by the two motors, respectively, so that the exposure opening is a large-format camera having a large aperture. Even in such cases, the shutter can be opened and closed at high speed and the shutter speed can be increased.
Further, in the camera shutter according to the present invention, since the two motors are arranged so as to face each other with the opening interposed therebetween, each member can be housed in a relatively small space, and the shutter can be prevented from becoming large. Further, in the camera shutter according to the present invention, since the width of the overlapping region of the opening shutter blades in the closed position is relatively large, the blades can be sufficiently accelerated before the opening starts, and from this point also, the shutter speed is increased. it can.
Further, in the camera shutter according to the present invention, since the inner edge of each shutter blade is formed in a straight line shape, the blade shape is the same as that of a conventional shutter blade without biting of each blade during the closing operation. In comparison, the size can be reduced, the inertia during operation can be reduced, and the shutter speed can be further increased. Furthermore, in the camera shutter according to the present invention, the closing shutter blade or the opening shutter blade is made thinner, which is also useful in increasing the shutter speed.

[Brief description of drawings]

FIG. 1 is a plan view of a shutter according to an embodiment of the present invention, showing a state before starting exposure.

FIG. 2 is a view similar to FIG. 1 showing a state after completion of exposure.

FIG. 3 is a timing chart for shutter operation.

FIG. 4 is a diagram showing a relationship between an opening / closing operation of a shutter blade and an approach distance.

FIG. 5 is a flowchart for shutter operation.

[Explanation of symbols]

2 ... Aperture, 3 ... First motor, 4, 5 ... Opening shutter blades, 9 ... Second motor, 10, 11 ... Closing shutter blades.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Ozeki Co., Ltd. 16-20, Shimura, Itabashi-ku, Tokyo 20-16 Copal Co., Ltd. Koichi Kobayashi 16-20, Shimura, Itabashi-ku, Tokyo 20-20 Copal, Inc. (72) Inventor Junichi Matsumoto, 16-20, Copal Co., Ltd., 2 Shimura, Itabashi-ku, Tokyo (72) Inventor Tomio Kurosu 16-20, Shimura, Itabashi-ku, Tokyo (20) Copal, Inc. (72) Inventor Toyonori Sasaki 16-20 Copal Co., Ltd. 2-2 Shimura, Itabashi-ku, Tokyo

Claims (5)

[Claims] 1. An exposure opening, an opening shutter blade that opens the exposure opening, a closing shutter blade that closes the exposure opening, and a first motor that operates the opening shutter blade. And a second motor for operating the closing shutter blade. 2. The camera shutter according to claim 1, wherein the first and second motors are arranged at positions facing each other with an exposure opening interposed therebetween. 3. A camera shutter in which exposure is controlled by opening and closing a shutter blade, a shutter blade for opening which is opened to start exposure, and a closing which is closed to end exposure. A shutter for a camera, comprising: an opening shutter blade, wherein the opening shutter blade has a larger area and a larger overlapping width between the blades in a closed state than the closing shutter blade. 4. The shutter for a camera according to claim 3, wherein inner edges of the opening shutter blade and the closing shutter blade are each formed in a straight line shape. 5. The camera shutter according to claim 1, wherein the closing shutter blade and the opening shutter blade are formed so as to have different thicknesses.