JP2000250094A - Focal plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focal plane shutter for a camera with a blade supporting constitution capable of miniaturizing the shutter and also capable of accomplishing the stable actuation of a slit forming blade. SOLUTION: A 2nd blade group is provided with an auxiliary arm 24, in addition to two arms 17 and 18 pivotally attached to a shutter base plate 1, blades 20, 21, 22 and 23. Besides, the auxiliary arm 24 is pivotally supported on the arms 17 and 18 by connection shafts 25 and 26, and the arm 24 nearly obliquely projects into an upper left direction and the arm 24 is attached to the leading end of the extending part of the blade 22 by a connection shaft 27. Then, the left, area of the slit forming blade 23 is partly held between the auxiliary arm 24 and the blade 22 in any actuating state, then, an irregular actuation phenomenon is effectively suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exposing a photosensitive surface by a slit formed by slit forming blades of two blade groups by sequentially operating a front blade group and a rear blade group in photographing. And a focal plane shutter for a camera.

[0002]

2. Description of the Related Art Recent cameras have been rapidly reduced in size due to the appearance of APS films. for that reason,
Further downsizing of the focal plane shutter built into the camera is also required. However, since considerable efforts have been made in miniaturization so far, it is not easy to meet the demand, and actually, in order to shorten the size of about 1 to 2 mm, The fact is that we are making great efforts.

When reducing the size of the focal plane shutter, how to reduce the area occupied by the periphery of the exposure aperture is a problem. However, the space above and below the exposure aperture is basically
The upper and lower dimensions of a plurality of blades constituting the blade group are restricted. In addition, one of the two lateral positions of the exposure opening, that is, the position on the tip side of each blade, allows stable operation of the blade tip, and the plurality of blades are in the deployed state. In such a case, light leakage must not occur, so that the same space as before is required. Therefore, it is conceivable to reduce the remaining space at the other side position, but for that purpose, it is necessary to make the shutter drive mechanism disposed there compact, and in addition to the conventional support structure of the shutter blades. You need to be creative. The shutter blade support structure thus devised is described in Japanese Utility Model Publication No. 57-5
No. 7367.

[0004] The present invention is basically in the same position as the device described in the above-mentioned publication, but can exhibit several effects superior in operation to the device described in the above-mentioned publication. It is related to such a configuration. So, first, it is necessary to better understand the present invention,
Points that are difficult to understand from the above publication will be described with reference to FIGS. 4 and 5. FIGS. 4 and 5 show a conventional configuration so that it can be easily compared with an embodiment of the present invention described later. Members and portions corresponding to the embodiment are as small as possible in the embodiment. , And are given the same reference numerals as in the embodiment. 4 and 5 show only the structure of the front blade group, FIG. 4 shows a state immediately before the start of the exposure operation of the front blade group, and FIG. 5 shows a state in the middle of the exposure operation. It is shown.

The shutter base plate 1 shown by a chain line in FIGS. 4 and 5 has an opening 1a at a substantially central portion, and the opening 1a regulates the exposure opening of the shutter. The four blades 9, 10, 11, and 12 of the front blade group are sequentially attached to two arms 6, 7 pivotally attached to the shutter base plate 1, and in FIG. Part 1
a is completely covered. In this configuration, the configuration according to the invention described in the above-mentioned publication means that as long as the number of blades is the same, the length of the arm itself cannot be shortened. For example, the position of 1a is moved to the left as shown by the two-dot chain line, and the right end of the shutter base plate 1 is set to the position of the two-dot chain line.

As a result, there is no problem at the tips (right ends) of the blades 9, 10, 11, and 12, since they may be shortened. However, on the other hand, the area on the left side of the opening 1a cannot be sufficiently covered. In FIG. 4 and FIG. 5, regions which should be completely covered are indicated by a plurality of parallel oblique lines. Therefore, in order to prevent this from occurring, each of the blades 9, 10,
It is necessary to stretch 11, 12 to the left. This is not specified in the detailed description of the invention in the above publication, but can be understood from the drawings. Although the connection relationship between the front blade group and the front blade drive member 28 shown in FIGS. 4 and 5 is not so obvious, the details will be understood in the description of the embodiment described later. can do. Also, a connecting plate 8 'interposed in the connecting structure.
Has a shape different from that of the embodiment, so that reference numeral 8 of the embodiment is indicated by adding “′”.

[0007]

By the way, each blade group in a recent focal plane shutter usually has two arms pivotally attached to a main plate and those arms via a connecting shaft which is a rivet part. It is composed of a plurality of blades that are pivotally supported. For this reason, there are many connection parts that are not fixed, and these connection parts are naturally provided with a tolerance. Moreover, at the time of the exposure operation, it is necessary to operate at a high speed. Therefore, the arms and the blades are made of a thin material, and are themselves easily bent parts.

For this reason, each blade group as a whole is designed to operate in a predetermined operating direction as a whole. However, a force in a complicated direction acts on each component to bend or bend. It is known that the material is temporarily deformed by being twisted or tilted. If the deformation is severe, the operation of the slit forming blade is affected, and an appropriate slit may not be formed. Further, at the end of the exposure operation, each blade group is stopped directly or indirectly by the stopper, but the impact at that time is extremely large, and the components of each blade group are largely deformed as described above. (Hereinafter, a deformation phenomenon caused by the action of a complicated force such as these will be referred to as a rash phenomenon). for that reason,
This may cause exposure unevenness or destruction at each connecting portion.

Therefore, various countermeasures have conventionally been taken in order to suppress such a phenomenon. As one of them, as can be seen from the description of the embodiment described later, a member called a blade holding plate is arranged over the entire operation region of the tip portion of each blade, and each blade group is stably It is known to be able to operate. Also,
To mitigate the shock when the exposure operation is stopped,
There are known ones in which various braking means are provided on a main plate or the like, or a cushioning means is provided.

However, if the blade supporting structure described with reference to FIGS. 4 and 5 is used in order to reduce the size of the shutter, the pivotal position of the slit forming blade, which is more important than the other blades, changes most. This results in a configuration in which the slit-forming blade is largely moved in the direction of the tip end. Therefore, although the deformation at the tip of the blade is suppressed by the above-mentioned holding plate, from the pivotal position with respect to the two arms,
The portions of the arms that are greatly extended in the direction of the pivot portion are extremely easily deformed. In addition, it is impossible to dispose a member corresponding to the above-mentioned pressing plate over the entire operation area of that part. Further, in the case of the rear blade group, when the operation is completed, the slit-forming blades are deployed very easily, but the slit-forming blades are in a very flexible state, but a means for directly suppressing the deformation of the largely stretched portion as described above, It is not easy to provide it on the main plate or the like.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a conventional blade supporting structure as disclosed in the above publication. By adding only one arm, it is possible to reduce the size of the entire shutter in the left-right direction, and furthermore, it is possible to effectively reduce the occurrence of the slit-forming blade, which tends to occur during operation or at the end of operation. It is an object of the present invention to provide a focal plane shutter for a camera which can suppress the occurrence of the focal plane shutter.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image processing apparatus wherein at least one of a leading blade group and a trailing blade group is pivotally attached to a main plate at a position on one side of an exposure opening. And two or more blades that are pivotally supported in the longitudinal direction of the arms in order and have the blade at the forefront as a slit forming blade, and one of the blades other than the slit forming blade. The blade has a projecting portion extending substantially obliquely as a whole in the direction of the pivot portion of the two arms and toward the slit forming edge of the slit forming blade, and one of the two arms The arm is directly pivoted to the other arm, but the other arm is pivotally supported by the other arm. To be attached In this case, the auxiliary arm is configured such that one blade other than the slit forming blade is directly pivotally supported, and the auxiliary arm is also pivotally supported by the one arm. The slit-forming blade and the two arms may be arranged between the two arms, and further, one blade other than the slit-forming blade may be a blade adjacent to the slit-forming blade. Thus, a suitable configuration is obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an embodiment shown in FIGS. These drawings are
All are plan views viewed from the subject side in a state where the exposure operation is started, and FIG. 1 shows a state immediately before the exposure operation is started. FIG. 2 shows a state in the middle of the exposure operation, and FIG. 3 shows a state immediately after the end of the exposure operation. In each of the drawings, it is necessary to make the drawings easy to see, so that portions that are considered to be understood by referring to other drawings are omitted.

First, the configuration of this embodiment will be described. The shutter base plate 1 is formed with an opening 1a in which a rectangle is horizontally elongated at a substantially central portion thereof, and on the left side of the opening 1a,
Two arc-shaped long holes 1b and 1c are formed. Well-known cushioning members are attached to the upper end surfaces of the long holes 1b and 1c, respectively, but they are omitted because they make it difficult to see the drawing when shown. Also, shutter base plate 1
On the subject side, that is, on the front side, axes 1d and 1e are erected, and on the back side, axes 1f, 1g, 1h, 1i, 1
j, 1k, 1m, 1n, 1p, 1q, 1r are erected.

On the rear side of the shutter base plate 1, an intermediate plate 2 is mounted on the shafts 1f, 1g, 1h. Make up. An opening 2a having a shape similar to that of the opening 1a is formed substantially at the center of the intermediate plate 2. However, the two long sides are formed in a mountain shape, and a steep notch 2b is formed at the peak position of the mountain shape on the upper side. Since the shape of such an intermediate plate 2 is well-known, the explanation of the reason for such a shape is omitted.

Further, on the back side of the intermediate plate 2, an auxiliary base plate 3 is provided.
Are attached to the shafts 1i, 1j, 1k, and 1m of the shutter base plate 1, and constitute a blade chamber of a rear blade group described later between the shutter plate 1 and the intermediate plate 2. In addition, the auxiliary base plate 3 is also formed with an opening 3a having substantially the same shape as the opening 1a of the shutter base plate 1 at a substantially central portion thereof. Also,
The opening 3a is arranged so as to overlap with the two openings 1a and 2a to regulate the optical path area of the photographing light, that is, the exposure opening. Since the opening is configured to be restricted only by the opening 1a, in the following description of the operation, the opening 1a will be described as being the same as the exposure opening.

Further, in addition to the above-described intermediate plate 2, a pressing plate 4 for the front blade and a pressing plate 5 for the rear blade are mounted on the shafts 1g and 1h of the shutter base plate 1. These holding plates 4 and 5 are in principle provided with the opening 1a in FIG.
In the right direction, that is, in the operating area at the tip of a plurality of blades described later. The front blade holding plate 4 is arranged between the shutter base plate 1 and the intermediate plate 2, and the rear blade holding plate 5 is arranged between the intermediate plate 2 and the auxiliary base plate 3. Further, the planar shape of these holding plates 4 and 5 may be the same, but in this embodiment, the opening 1a is provided.
As shown in FIG. 1, the shape of the front blade holding plate 4 overlaps with the cut 2 b of the intermediate plate 2, and the edge of the opening 1 a side is substantially the same as the edge of the intermediate plate 2. It is formed to match.

FIG. 2 shows a state in which the intermediate plate 2, the auxiliary base plate 3, the front blade holding plate 4, and the rear blade holding plate 5 shown in FIG. 1 are removed, and the shutter base plate 1 and two driving members to be described later are shown by alternate long and short dash lines. It is shown by. Therefore, the configuration of the front blade group and the configuration of the rear blade group are easier to understand with reference to FIG. 2 than to FIG.

Therefore, the structure of the front blade group will be described first. Arms 6 and 7 are pivotally attached to the shafts 1n and 1p of the shutter base plate 1, respectively. In the vicinity of the pivot portion of the arm 6, a shaft 6a is erected toward the shutter base plate 1, and a connecting plate 8 is pivotally mounted thereon. However, when actually manufactured, the connecting shaft, which is a rivet part, is connected to the arm 6 in the same manner as the mounting configuration of a plurality of blades described later.
It is preferable to insert the connecting end into the hole formed in the connecting plate 8 from the connecting plate 8 side and fix the inserted end to the arm 6 by caulking. In addition, as can be understood from the following description, the free end of the connecting plate 8 attached in such a manner, in any state,
It always overlaps with a part of the other arm 7 so that it can contact.

The two arms 6, 7 are provided with four blades 9, 10, 1 from their pivotal connection portion toward the tip.
1, 12 are attached in order. The overlapping relationship of the blades is as follows: the blade 9 is closest to the intermediate plate 2 side, and the blade 12 is closest to the shutter base plate 1 side, that is, the arm 6,
7 side. Further, the blade 12 attached to the most distal end side of the arms 6 and 7 is a slit forming blade,
The other blades are to be distinguished from the slit forming blades 12,
Generally, it is a blade that is referred to as a covering blade. The leading ends of all of the blades 9, 10, 11, and 12, ie, the rightward ends in the respective drawings, operate between the intermediate plate 2 and the front blade holding plate 4. .
In FIG. 3, only the slit forming blade 12 is shown, and other blades 9, 10, and 11 are not shown.

Further, the way of attaching the four blades 9, 10, 11, 12 to the arms 6, 7 is as follows.
2 is the same as the conventional case, but the blade 11 has a unique mounting method. That is, the blades 9, 10, 12
In the case of, as is well known, two connecting shafts, which are rivet parts, are inserted into the holes formed in the arms 6, 7 and the blades 9, 10, 12 from the side of the arms 6, 7 and swaged. Thus, the insertion end is fixed to each of the blades 9, 10, and 12. However, between each connecting shaft and the arms 6 and 7,
It is rotatable. It is needless to say that it is not necessary to fix the tip of the connecting shaft to the blades 9, 10, 12 as long as the connecting shaft is prevented from coming off.

On the other hand, in order to mount the blades 11, an auxiliary arm 13 is specially arranged between the arms 6, 7 and the slit forming blades 12, and extends substantially obliquely to the lower left. Part. The three connecting shafts used for mounting the blades 11 are parts having the same shape as the other connecting shafts described above. However, in order to explain the mounting structure of the auxiliary arm 13 in detail, these three connecting shafts are used. Are especially designated by the reference numerals 14, 15, 16.

Therefore, first, the connecting shaft 14 is connected to the arm 6,
The holes formed in the auxiliary arm 13 and the blade 11
It is inserted from the side, and its inserted end is fixed to the blade 11 by caulking. However, the connection shaft 14 and the arm 6 and the auxiliary arm 13 are individually rotatable. It is preferable that the connecting shaft 14 is fixed to the blade 11, but this is not essential if some kind of retaining means is provided.

The connecting shaft 15 is inserted into a hole formed in the arm 7 and the auxiliary arm 13 from the arm 7 side, and the inserted end thereof is fixed to the auxiliary arm 13 by caulking. However, the connection shaft 15 and the arm 7 are rotatable. Also in this case, it is not essential to fix the connecting shaft 15 to the arm 13 as long as the connecting shaft 15 is prevented from coming off by other means.

Further, the blade 11 is different from the usual shape, and has a projecting portion which extends substantially obliquely to the lower left like the projecting portion of the auxiliary arm 13. The two overhanging portions sandwich the slit forming blade 12, and their leading ends are attached by a connecting shaft 16. The mounting method is such that the connecting shaft 16 is
3 and a hole formed in the blade 11 from the auxiliary arm 13 side.
It is fixed to. In the case of the present embodiment, the space between the auxiliary arm 13 and the blade 11 is also fixed by the caulking process. However, it is theoretically possible to make it rotatable.

As described above, in this embodiment, the position of the exposure opening, that is, the position of the opening 1a, is moved toward the pivoting portion of the arms 6 and 7 as compared with the conventional case, and the size of the entire shutter in the left-right direction is reduced. I'm making it smaller. However, since the lengths of the arms 6 and 7 cannot be reduced, the slit forming blade 1 that is the most important for exposure and has the largest operation amount.
In the case of No. 2, the length from the mounting position to the arms 6 and 7 to the distal end is shorter, but the length of the arms 6 and 7 in the direction of the pivot portion must be larger than before. ing. According to the present embodiment, the region formed longer than before is sandwiched by the overhang of the auxiliary arm 13 and the overhang of the covering blade 11, and the operation described later is performed. As can be seen from the description, this configuration is maintained in any state.

Next, the structure of the rear blade group will be described. As can be seen from FIG. 2, the structure of the rear blade group is the same as the above-mentioned structure of the front blade group.
This will be described more simply than the configuration of the front blade group described above. Therefore, the description of the omitted items is based on the description of the front blade group. In FIG. 1, the shapes of the four blades of the rear blade group are partially omitted for easy viewing of the drawing.

Arms 17 and 18 are pivotally mounted on the shafts 1q and 1r of the shutter base plate 1, respectively. A shaft 17a is erected near the pivotal portion of the arm 17 toward the auxiliary base plate 3, and a connecting plate 19 is pivotally attached thereto. The free end of the connecting plate 19 is always connected to the other arm 1 in any operating position by the configuration described later.
8 so as to be able to come in contact with it. still,
The mounting configuration of the connecting plate 19 to the arm 17 is not limited to such a configuration. Actually, it is preferable to adopt a configuration in accordance with the mounting configuration of each blade. Is the same.

The two arms 17 and 18 are provided with four blades 2 from their pivotal joints toward their tips.
0, 21, 22, 23 are attached in order. The overlapping relationship of the blades is such that the blade 20 is closest to the intermediate plate 2 side, and the blade 23 is closest to the auxiliary base plate 3, that is, the arm 1
7, 18 side. The blades 23 attached to the tips of the arms 17 and 18 are slit forming blades, and the other blades are covering blades. The leading ends of all of the blades 20, 21, 22, and 23 operate between the intermediate plate 2 and the rear blade holding plate 5.

Further, the blades 2 for the arms 17 and 18
How to attach 0, 21 and 23 is to the blades 9 and 1 of the front blade group.
This is the same as in the case of 0, 12, except that the two connecting shafts are inserted into the holes formed in the arms 17, 18 and the blades 20, 21, 23 from the arms 17, 18 side. Are caulking them so that their insertion ends are
21 and 23. However, the space between each connecting shaft and the arms 17 and 18 is rotatable.

On the other hand, the way of attaching the blade 22 is different, and an auxiliary arm 24 arranged between the arms 17 and 18 and the slit forming blade 23 is interposed. Three connecting shafts are used for mounting the blades 22, and they are particularly designated by reference numerals 25, 26, and 27. First, the connecting shaft 25 is inserted from the arm 17 side into holes formed in the arm 17, the auxiliary arm 24 and the blade 22, and the inserted end is fixed to the blade 22.
Between the connecting shaft 25 and the arm 17 and the auxiliary arm 24,
Individually rotatable. The connecting shaft 26 is inserted into the holes formed in the arm 18 and the auxiliary arm 24 from the arm 18 side, and the insertion end is fixed to the arm 18. It is rotatable.

Further, a protruding portion extending substantially obliquely to the upper left is formed on the blade 22 in the same manner as the auxiliary arm 24.
Is attached by a connecting shaft 27 to the distal end position of the overhang. In addition, the connecting shaft 27 is attached to a hole formed in the auxiliary arm 24 and the blade 22 by the auxiliary arm 2.
It is inserted from the 4 side and is fixed to the blade 22. At this time, the space between the auxiliary arm 24 and the blade 22 is also fixed. As described above, also in the case of the rear blade group, the slit forming blades 23 are configured to be sandwiched between the auxiliary arm 24 and the blades 22 on the side of their attachment portions with respect to the mounting positions with respect to the arms 17 and 18. ing.

Next, a description will be given of a drive mechanism for operating the front blade group and the rear blade group. FIGS. 1 to 3 show such a drive mechanism which is necessary for the description of this embodiment. Only the blade driving member 28 and the rear blade driving member 29 are shown. Further, these drive members 28 and 29 are shown so that the positional relationship and the connection relationship with the respective blade groups described above can be understood. Therefore, the shapes and configurations of parts not particularly related to those are omitted. In addition, although a driving mechanism is configured, a known configuration is applied to other members and parts that are not illustrated.

As shown in FIG. 1, the front blade driving member 28 and the rear blade driving member 29 in this embodiment are rotatably mounted on the shafts 1d and 1e of the shutter base plate 1 described above. Then, the respective drive pins 28a, 29a
Is the above-described arc-shaped long hole 1 formed in the shutter base plate 1.
b, 1c, and fits into holes formed in the connecting plates 8, 19. Therefore, each driving member 28, 29
When rotated by d and 1e, the arms 6 and 17 are rotated through the connecting plates 8 and 19 in the same rotation direction as the driving members 28 and 29. During the exposure operation, the driving members 28 and 29 are rotated counterclockwise by the urging forces of the driving springs (not shown).

In this embodiment, the positions of the driving members 28 and 29 are different from the normal positions. That is, in the normal case, the shafts 1d and 1e serving as the rotation axes of the driving members 28 and 29 are arranged on the same axis as the shafts 1n and 1q serving as the rotation axes of the arms 6 and 17. Therefore, the drive pins 28a and 29a are fitted into holes formed in the arms 6 and 17, and the connecting plates 8 and 19 as in this embodiment are not provided.

As is well known, in the area where the driving members 28 and 29 are mounted on the shutter base plate 1, a number of members (not shown) such as a set member and an electromagnet are mounted. , They are operatively interconnected. Therefore, due to the overall configuration of the shutter, the shape and size of each drive member
In addition to being restricted, there are cases where the interval between the rotation axes must be reduced. Such a requirement may arise not only from a design problem of the shutter unit but also from a design of the entire camera.

However, even in such a case, the interval between the axes 1n and 1q cannot be reduced. Since this interval is set in advance at a position where the size can be reduced as much as possible, if the interval is reduced, the arms 6, 7 and the arms 17, 18 will interfere with each other during operation. It is. Therefore,
In some cases, it is unavoidable to configure as in the embodiment. For this reason, in the case of the present embodiment, the configuration is as shown in the figure. However, the present invention is not limited to such a configuration and can be applied to a conventional configuration. Needless to say,

Next, the operation of this embodiment will be described. FIG. 1 shows the state immediately before the start of the exposure operation, that is, the driving member 28 for the leading blade.
And the state where the rear blade drive member 29 is at the exposure operation start position. Therefore, the blades 9, 10, 1 of the front blade group
The blades 1 and 12 are in the unfolded state and cover the opening 1a, and the blades 20, 21, 22, and 23 of the rear blade group are stored in a superimposed state at a position below the opening 1a. The driving members 28 and 29 are pressed against the urging forces of the respective driving springs,
Several configurations are known for maintaining this state. Although the present embodiment does not illustrate such a configuration, the present invention is applicable to all of those configurations. Further, it is called a double light shielding type shutter. In the set state, the opening 1a is covered by both the front blade group and the rear blade group, and the rear blade group is located just before the start of the exposure operation. , The state shown in FIG. 1 is known, but the present invention can be applied to such a state.

After the release button of the camera is pressed, from the state shown in FIG. 1, first, the leading blade driving member 28 starts rotating counterclockwise by the urging force of the leading blade driving spring (not shown). After a predetermined time, the driving member 2 for the rear blade
9 starts rotating counterclockwise by the urging force of the rear blade drive spring (not shown). At this time, the drive pin 28a of the leading blade drive member 28 rotates the arm 6 in the counterclockwise direction via the connecting plate 8, and the drive pin 29a of the trailing blade drive member 29 via the connecting plate 19. Arm 1
7 is rotated counterclockwise.

For this reason, the four blades 9, 1 of the leading blade group
Numerals 0, 11, and 12 operate upward while increasing the overlap therebetween, and the opening 1 a is opened by the slit forming blades 12. On the other hand, the four blades 20, 2
The slits 1, 22, and 23 operate upward while reducing the overlap therebetween, and close the opening 1a so that the slit forming blades 23 follow the slit forming blades 12 described above. Then, the photosensitive surface is exposed by the slit formed by the two slit forming blades 12 and 23, and such a state in the middle of the operation is shown in FIG. Also, as can be seen from FIG. 2, even in this state, the free ends of the connecting plates 8, 19 maintain the overlapping relationship with the arms 7, 18.

By the way, during such an operation, not only the force for operating the blade upward but also the force in the complicated direction for causing the thin blade to bend for the reasons described above. Works. Above all, the slit forming blades 12 and 23 are most susceptible to the influence, though they are important blades. The reason is that, compared to the other covering blades, the operation amount is the largest and the area where both surfaces are in contact with other members is small. Therefore, in the present embodiment, as is conventionally done, the blade holding plates 4 and 5 are arranged over the entire operation area of the tip end of each blade to suppress the bending of the blade. .

Further, in the case of the present embodiment, special measures are taken only for the slit forming blades 12 and 23. That is, in this embodiment, as described with reference to FIGS. 4 and 5, in order to reduce the size of the shutter, the slit forming blades 12 and 23 are moved from the positions attached to the two arms, respectively. The area of the arm in the direction of the pivot has to be longer than before. Therefore, those regions are much easier to bend than before. However, in this embodiment, during operation, a part of the area is always set to the auxiliary arms 13 and 24 and the covering blades 11 and 24.
Since it is sandwiched by 22, the bending thereof is suppressed.

Thus, the leading blade group and the trailing blade group continue the exposure operation. Thereafter, the four blades 9, 10, 11, and 12 of the leading blade group are superimposed to form the opening. 1a
Is stored in the upper position of the front blade,
The drive pin 28a comes into contact with a buffer member (not shown) attached to the upper end surface of the elongated hole 1b and stops.
Immediately after that, the four blades 20, 21, 22 of the rear blade group
When the opening 2a and the opening 23 are completely covered with each other, the rear blade driving member 29 has its driving pin 29a attached to the upper end surface of the elongated hole 1c (not shown). It stops when it comes into contact with the buffer member.
FIG. 3 shows a state immediately after the stop. However, as for the blades of the front blade group, only the slit forming blades 12 are shown for easy viewing of the drawing.

By the way, when the exposure operation is completed in this way, as is well known, the front blade group and the rear blade group receive an extremely large impact, and a strong rash phenomenon occurs. At this time, since the four blades 9, 10, 11, and 12 of the front blade group are in a superimposed state, the movement in the bending direction is relatively suppressed. For this reason, it is more important to prevent the slit forming blades 12 from temporarily entering the opening 1a due to the bouncing during the stop.

However, the rear blade group is more troublesome than the front blade group. That is, when the rear blade group is stopped, the four blades 20, 21, 22, and 23 are in the deployed state, the amount of mutual overlap is small, and most of the plane area is within the opening 1a. From that
This is because the state is very easy to bend. Therefore, due to the bounce at the time of stop, the slit forming blade 23
Not only temporarily prevent a part of the opening 1a from being opened, but also prevent the light from leaking from the overlapping portion of the blades due to the violent rash phenomenon, and the mounting portion of each blade. It is necessary to prevent such things from being destroyed. Therefore, conventionally, as a countermeasure, an arm or a blade constituting the blade group is provided with a braking unit or a buffer unit having various configurations.

However, as described above, the slit forming blade 23 of the present embodiment has a region in the direction from the mounting portion to the arms 17 and 18 toward the pivoting portion of the arms 17 and 18 compared to the conventional slit forming blade. Since it is formed to be long, the force in the bending direction due to the impact at the time of stop also largely acts on that area. However, the direct braking means and the buffer means for the area are not
And it is very difficult to provide it on the auxiliary base plate 3. However, according to the present embodiment, even during such a stop,
Since a part of the above-described region is sandwiched between the extension portions of the auxiliary arm 24 and the blades 22, the region is in a state where it is hardly bent. Therefore, since the overall size of the shutter in the left-right direction is reduced, there is no possibility that the shutter is more greatly affected by the blurring phenomenon.

Next, the setting operation of this embodiment will be described.
In the state shown in FIG. 3, when the film is wound up, a set member (not shown) is operated in conjunction therewith, and the leading blade drive member 28 and the rear blade drive member 29 are actuated.
Is rotated clockwise at a predetermined timing. That is,
The set member firstly includes only the leading blade drive member 28,
The blade is rotated clockwise against the urging force of the driving spring for the leading blade (not shown). Thereby, the drive pin 28a rotates the arm 6 clockwise via the connecting plate 8, so that
The four blades 9, 10, 11, and 12 of the front blade group operate downward with the slit forming blade 12 at the top while reducing the amount of overlap between them.

Then, the slit forming blades 12 of the front blade group
When the amount of overlap between the slits and the slit forming blades 23 of the rear blade group reaches a predetermined amount, the set member pushes the rear blade drive member 29 against the biasing force of the rear blade drive spring (not shown). And rotate it clockwise. Thereby, the driving pin 29
a rotates the arm 17 clockwise through the connecting plate 19, so that the four blades 2 covering the opening 1a
0, 21, 22, and 23 operate downward while increasing the amount of mutual overlap. Therefore,
The blades of the leading blade group and the blades of the trailing blade group operate downward while maintaining the overlapping amount of the slit forming blades at a predetermined amount. Thereafter, the blades 9, 10, 11, and 12 of the front blade group are deployed to cover the opening 1a, and the blades 20, 21, 22, and 23 of the rear blade group are overlapped to form the opening 1a. When the storage state is reached at the lower position, the setting operation by the setting member is completed.

The driving members 28 and 29 are maintained in the set state until the release button of the camera is depressed at the time of the next photographing. Stop type and direct type. The locking type is employed even when the timing of the exposure operation has recently been electrically controlled. And each drive member 28, 29
In the set position, it is locked by the locking member, and after the release, the lock is released,
The exposure operation is started. Therefore, in the case of this type, the drive member 28, 29 has the same set position and the exposure operation start position.

The other type is called a direct type, which is a unique configuration born after the start of the exposure operation of each of the driving members 28 and 29 is electrically controlled. In this type, each driving member 2
The setting positions 8 and 29 are maintained by the setting members that remain at the setting positions even after the setting operation. Then, immediately after the release of the camera, each driving member 2
After the electromagnets 8 and 29 are held by the respective electromagnets, the set member returns to the pre-setting position, and the exposure operation is started by sequentially releasing the holding force of the electromagnets. Therefore, detailed description is omitted because it is well known,
In the case of this type, the driving members 28 and 29 have slightly different set positions and exposure operation start positions.

Further, irrespective of the difference between the above two types, there is also a double light-shielding type shutter as described above as a modification thereof. However, regardless of the type of drive mechanism, each drive member 28, 29 must be located at the exposure operation start position immediately before the start of the exposure operation. Therefore, in any case, immediately before the start of the exposure operation, each driving member 2
8, 29 are in the state shown in FIG.

In this manner, a series of operations are performed. As can be seen from the above description, in this embodiment, the connecting plates 8, 1 attached to the arms 6, 17 are used.
Reference numeral 9 denotes the state immediately before the start of the exposure operation shown in FIG. 1, the state in the middle of the exposure operation shown in FIG. 2, and the state immediately after the end of the exposure operation shown in FIG. Their free ends are designed to always overlap the arms 7,18. The reason is that during operation,
This is to prevent the connecting plates 8 and 19 and the arms 7 and 18 from colliding.

As described above, the arms 6, 7, 1
Since the shafts 7 and 18 are pivotally attached to the shafts 1n, 1p, 1q and 1r, they can move in the axial direction of the shafts, though very slightly, due to tolerances. It can also tilt with respect to the axis of the shaft. Also,
The arms 6, 7, 17, and 18 are formed of a relatively thin material in an elongated shape, so that the arms are easily bent. Further, as described above, when each blade group operates, not only a simple force in the vertical direction of the drawing acts on each blade group, but also a complicated force in the vertical direction or the like acts on each blade group. ing. Therefore, arms 6, 7, 17,
The 18 is more or less flexed or twisted by such complex forces.

Under such circumstances, if the length of the connecting plates 8 and 19 is set to be the length of the fitting portion with the driving pins 28a and 29a, for example, In the case where the connecting plate 8 'shown in FIG. 4 is used, the arm 7 collides with the connecting plate 8' in the process from the state shown in FIG. 2 to the state shown in FIG. Resulting in. However, the connecting plates 8 and 19 of this embodiment are
Since their free ends are formed to extend from the fitting portions with the drive pins 28a, 29a, and their free ends always overlap the arms 7, 18,
During operation, such a collision does not occur.

In this embodiment, the connecting plates 8, 19
Are pivotally attached to the arms 6 and 17 on the side where the blades are not attached. The reason for this is still nothing to do with downsizing of the shutter. This can be understood, for example, by looking at the relationship between the connecting plate 8 and the blade 9 in FIG. That is, in the case of the present embodiment, if the connecting plate 8 is pivotally attached to the surface of the arm 6 on the side of the intermediate plate 2, the positional relationship is such that it can collide with the blade 9 in the state shown in FIG. In the case of the other connecting plate 19, when the arm 17 is pivotally attached to the surface of the arm 17 on the side of the intermediate plate 2, the blade 2 in the state shown in FIG.
It becomes a positional relationship that can collide with 0.

In order to prevent such a collision from occurring, the dimensions from the shafts 1d and 1e to the drive pins 28a and 29a are reduced, or the mounting positions of the blades 9 on the arms 6 and 7, and the arms 17 and It is necessary to move the mounting position of the blade 20 with respect to 18 toward the tip of each arm. However, in the former case, as can be easily predicted from the arrangement configuration on the drawing, if the above dimensions are further reduced, the amount of set force of each of the driving members 28 and 29 becomes extremely large. It becomes poor in nature.

On the other hand, in the latter case, it is not necessary to use only the blades 9 and 20, and it is necessary to move the other blades in order. Therefore, as can be understood from the positional relationship of the left end of each blade in FIG. The position of the opening 1a must be moved to the right side, and the meaning of reducing the size of the shutter is reduced. Therefore, in this embodiment, the connection plates 8 and 19
Are pivotally attached to the surfaces of the arms 6 and 17 to which the blades are not attached. However, depending on the degree of miniaturization,
The connecting plates 8 and 19 may be pivotally connected to the surfaces of the arms 6 and 17 on which the blades are mounted. In this case, the free ends extending from the connecting plates 8 and 19 are always connected to the arms 6 and 17 at all times. If they are overlapped on 7, 18, it is possible to prevent collision during operation.

In the above embodiment, the auxiliary arm 13 is also attached to the arm 6 by the connecting shaft 14, but this is achieved by attaching the auxiliary arm 13 to both the arm 6 and the arm 7. The purpose of this is to make it easier to maintain the relative positional relationship between the arms 6 and 7 during operation and to effectively suppress the swelling phenomenon. Alternatively, it may be simply attached to the arm 7 and the blade 11. In the above embodiment, the auxiliary arm 13
Are arranged between the arms 6 and 7 and the slit forming blades 12, but they may be attached to the opposite surfaces of the arms 6 and 7. Further, in the above embodiment, the blade 1
1 is formed with an overhang, but instead, for example,
An overhang may be formed on the blade 10. The same is true not only for the front blade group but also for the rear blade group.

In the above embodiment, the holding plates 4 and 5 are provided in the working area at the tip of each blade.
In recent years, the shutter base plate 1 and the auxiliary base plate 3 are made of synthetic resin, and the operating regions at the tips of the blades are formed thick to eliminate the need for the holding plates 4 and 5 as described above. Configurations are also known. The present invention can be applied to a shutter having such a configuration, and even when a holding plate is provided, its shape is not limited to the shape of the embodiment. Furthermore, recently, it is also known that two arms pivotally supporting a plurality of blades are pivotally attached not to the shutter base plate but to an auxiliary base plate.
It goes without saying that the present invention can be applied to such a shutter.

[0060]

As described above, according to the present invention, the slit is formed by attaching the auxiliary arm to at least one of the two arms pivotally attached to the main plate and supporting the plurality of blades. The blade is always pinched by the auxiliary arm and another blade from the position pivotally supported by the two arms by the auxiliary arm and one other blade in any operating position. , It is possible to reduce the size of the entire shutter in the left-right direction, and to effectively suppress the phenomenon that the slit forming blades are likely to occur without increasing the number of parts. There is an advantage that can be.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment viewed from a subject side, showing a state immediately before an exposure operation is started.

FIG. 2 is a plan view of the embodiment as viewed from the subject side, and shows the state of the front blade group and the rear blade group during the exposure operation so as to be easily understood.

FIG. 3 is a plan view viewed from the subject side in the same manner as FIG. 2 and mainly shows a state immediately after the end of the exposure operation of the rear blade group so as to be easily understood.

FIG. 4 is a plan view of a focal plane shutter shown for comparison with the embodiment, and shows a front blade group in a state immediately before the start of an exposure operation.

5 is a plan view showing a state where the front blade group shown in FIG. 4 is in the middle of an exposure operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a, 3a Opening 1b, 1c Slot 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1
m, 1n, 1p, 1q, 1r, 6a, 17a Shaft 2 Intermediate plate 2b Cut 3 Auxiliary base plate 4 Press plate for front blade 5 Press plate for rear blade 6, 7, 17, 18 Arm 8, 8 ', 19 Connection plate 9, 10, 11, 12, 20, 21, 22, 23 Blade 13, 14 Auxiliary arm 14, 15, 16, 25, 26, 27 Connecting shaft 28 Front blade drive member 28a, 29a Drive pin 29 Rear blade drive Element

Claims (4)

[Claims] At least one of a leading blade group and a trailing blade group has two arms pivotally attached to a main plate at a position on one side of an exposure opening, and a pivotal support in order in the longitudinal direction of the arms. And a plurality of blades, each of which has a blade on the leading edge side as a slit forming blade, and one blade other than the slit forming blade is in the direction of the pivotal connection of the two arms and has a slit. In the direction toward the slit forming edge side of the forming blade, it has a projecting portion extending substantially obliquely as a whole, and is directly pivotally supported on one of the two arms, while the other arm is Wherein the projecting portion is attached to an auxiliary arm pivotally supported by the other arm at a position beyond the slit forming edge. 2. The auxiliary arm according to claim 1, wherein one of the blades other than the slit forming blade is directly pivotally supported, and the auxiliary arm is also pivotally supported by the one arm. Focal plane shutter for camera. 3. The focal plane shutter for a camera according to claim 1, wherein the auxiliary arm is disposed between the slit forming blade and the two arms. 4. The focal plane shutter for a camera according to claim 1, wherein one blade other than the slit forming blade is a blade adjacent to the slit forming blade.