JP2001083571A - Focal plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focal plane shutter constituted so that an arm and a blade constituting a blade group are suitably prevented from being displaced or deflected in the axial direction of an optical axis in the midst of actuation. SOLUTION: A shutter base plate 1 is made of synthetic resin. Then, four preventing stripes 1w, 1x, 1y and 1z are formed thick at the blade chamber side of the rear blade group by molding integrally with the plate 1 in order to prevent the arms 4 and 5 and the blades 6, 7, 8 and 9 from being displaced or deflected to the plate 1 side in the midst of actuation. The stripes 1w, 1x and 1y with which the arms 4 and 5 are brought into slidable contact are formed in a circular arc state which does not adopt shafts 1m and 1v as a center and the strip 1z with which the blades 6, 7, 8 and 9 are brought into slidable contact is formed straight in a direction that it does not coincide with the actuation loci of the blades 6, 7, 8 and 9. Therefore, since the parts of the arms and the blades brought into slidable contact with the stripes 1w, 1x, 1y and 1z are continuously changed, the arms and the blades become hard to be damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Most of recent focal plane shutters have two blade chambers formed by partitioning most of a space between two ground plates with an intermediate plate, and these blade chambers have a front blade group and a rear blade group. The blades are arranged. Each of the blade groups has substantially the same configuration. Basically, two blades are pivotally attached to one of the base plates at one side position of the exposure opening, and the other has a horizontally long shape. It consists of a plurality of blades that are pivotally supported in the longitudinal direction of the two arms by one connection shaft at a time, and among the plurality of blades, the blade is pivotally supported at the tip of the arm. The blade is a slit forming blade. Exceptionally, it is also known that the arm has three or more arms. Even in such a case, one blade is pivotally supported on any two of the arms. I am trying to.

[0003] Further, as a specific pivotal structure of each blade with respect to the two arms, generally, the arm and the blade are overlapped, and rivet parts are used for holes formed in them. The connecting shaft is inserted from the arm side, and the inserted end is swaged against the blade. When arranging each blade group in each blade chamber, it is usual that a plurality of blades are set to the intermediate plate side and the arm is set to the main plate side. It will stick out. In addition, each blade group has a lot of pivot portions having such a configuration, and a fitting portion between the hole and the shaft is provided with a tolerance. In such a case, rattling of the fitting portions becomes a major factor, causing a complicated operation, which makes it impossible to perform appropriate exposure control by the slit forming blades or breaks the blade group. It will be.

[0004] In order to solve such a situation, how to prevent a blade or an arm made of a thin material from being displaced or deformed in the axial direction of the optical axis during operation. The key point is how to reduce the impact when the exposure operation is stopped.However, since it is impossible to actually solve it with only one countermeasure, The reality is that various types of measures are adopted and resolved.
The present invention is an improvement of a countermeasure that devises a synthetic resin base plate in order to prevent the blades and arms from being displaced and deformed in the axial direction of the optical axis during operation. It is about.

[0005] By the way, as is well known, the two ground plates are:
The opening formed in the substantially central portion is arranged so as to overlap the opening formed in the intermediate plate, and at least one of the openings regulates the shape of the rectangular exposure opening. I have to. In a normal photographing posture of the camera, the exposure opening is usually a horizontally long rectangle, and the arms of each of the above-mentioned blade groups are arranged on one short side of the exposure opening. It is pivoted to the position.

For this reason, the distance between the base plate and the intermediate plate at one short side is the sum of the thickness of the plurality of blades, the thickness of the arm, and the amount of protrusion of the head of the connecting shaft. At least a dimension is required, but since there is no arm at the side position of the other short side, an extra space is left by the thickness of the arm and the amount of protrusion of the head of the connecting shaft. . The extra space allows the tip of the blade (the end on the opposite side of the pivot with respect to the arm) to be easily displaced in the axial direction of the optical axis.
Japanese Patent Application Laid-Open No. 10-133255 discloses a configuration in which a portion of a synthetic resin base plate that is in sliding contact with the tip of a blade is made thick to fill the extra space as much as possible.

[0007]

By the way, considering only the purpose of suppressing the displacement and deformation of the blade group in the axial direction of the optical axis, in the above-mentioned publication, the blade is formed in the working area at the tip end of the blade. Normally, such a thick portion is preferably formed outside the two long sides of the exposure opening so as to be in sliding contact with the blade. However, if the sliding surface is too large, on the contrary, the operating speed of the blade group is affected, so when forming a thick portion for such a purpose, it is necessary to substantially follow the operating direction of the blade. Thus, it is conceivable that the thick portion is formed in a rail shape.

On the other hand, also in the side region where the arm is pivotally connected, the distance between the intermediate plate and the ground plate is made as small as possible so that the displacement and deformation of the blade group in the axial direction of the optical axis can be suppressed. Is preferred. However, in this case, as the number of times of photographing increases, the head of the metal connecting shaft cuts the base plate made of synthetic resin, so that the initial operating speed cannot be obtained. Therefore, in this region, it is preferable that the base plate does not slide as much as possible on the head of the connecting shaft but forms a thick portion so that the arm can slide. In this case, it is a common idea that the thick portion is formed in an arc around the pivot axis of the arm, that is, the rotation center of the arm. Although the purpose is completely different, the thick portion is not formed so as to be in sliding contact with the arm in order to suppress the displacement and deformation of the arm, but the synthetic resin is formed around the center of rotation of the arm. An example in which an arc-shaped thick portion is formed on a base plate made of aluminum is described in JP-A-7-325334.

As described above, for the purpose of suppressing the displacement and deformation of the blade group in the axial direction of the optical axis, the thick portion is formed so as to be in sliding contact with the blade in the region outside the two long sides of the exposure opening. When forming a thick portion in the side region where the arm of the exposure opening is pivoted so as to be able to slide on the arm, the shape of the thick portion is Generally speaking, it is common to form a rail along the operating trajectory of a blade or arm. By doing so, the tentative purpose can be achieved. However, when such a thick portion is formed, only a specific portion of the blade or arm always comes into sliding contact with the thick portion, and the thick portion is formed in a relatively thin rail shape. Therefore, there is a problem that the sliding surfaces of the blades and the arm are easily damaged.

The present invention has been made to solve such a problem, and an object of the present invention is to suppress displacement and deformation of a blade group in the axial direction of an optical axis.
Even if the thick portion is formed in a rail shape so as to be able to slidably contact with the blade in the region outside the two long sides of the exposure opening, also in the side region where the arm of the exposure opening is pivoted, Even if the thick portion is formed in a rail shape so as to be able to slidably contact with the arm, a focal plane shutter for a camera in which the slidable portion of the blade or the arm with respect to the thick portion changes with the operation of the blade group. To provide.

[0011]

According to a first aspect of the present invention, there is provided a focal plane shutter for a camera, wherein a front blade group and a rear blade group partition two ground plates by an intermediate plate. The two blades are separately arranged in the two formed blade chambers.Each blade group includes two arms pivotally connected to one of the two base plates in a side region of the exposure opening, and a rivet member attached to the two arms. A plurality of blades that are pivotally supported in sequence using a connection shaft, and at least one of the blade groups is configured such that the two arms form a blade chamber of the blade group more than the plurality of blades. The base plate that is disposed on the side of the base plate that protrudes the head of the connecting shaft and that forms the blade chamber of the blade group is made of synthetic resin, and the two when the blade group is operated. Suppression that can slide on at least one of the arms And the rotation center of the arm so as are integrally molded as a thick portion in an arc shape not concentric. In this case, at least in the final operation area where the one or more blades cover the exposure opening, one or more of the restraining strips are provided in a side area of the exposure opening where the two arms are pivotally connected. , In the direction of its operation, if it is formed so that the thickness gradually increases,
The operation of the blade group is further stabilized, and furthermore, it is possible to appropriately prevent light leakage when covering the exposure opening, and when the blade group is the rear blade group, in the final stage of the exposure operation Braking can be suitably performed. Also,
In order to achieve the above object, the focal plane shutter for a camera according to claim 3, wherein the front blade group and the rear blade group are separately provided in two blade chambers formed by dividing two ground plates with an intermediate plate. Each blade group is arranged, two arms pivotally attached to one of the two base plates in a side region of the exposure opening, and the two arms are pivotally supported in order by using the connection shaft of a rivet member to the two arms. It consists of multiple blades,
The base plate forming the blade chamber of at least one of the blade groups is made of a synthetic resin, and the base plate has a restraining strip that at least the blades on the base plate side can slide on when operating.
The blade is integrally formed as a thick portion so as to be in sliding contact with a different portion of the blade during the operation. Furthermore,
4. The focal plane shutter for a camera according to claim 1, wherein the one blade group is a front blade group, and the restraining streak is a side region of an exposure opening pivotally connected to the two arms, and At least one is provided in at least one of an area where the plurality of blades are superimposed and stored, and at least one of the restraining strips is directed toward the operation direction in at least a final area of the exposure operation. Therefore, if the thickness is gradually increased, the front blade group can be suitably braked during the exposure operation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the embodiments shown in FIGS. 1 to 6
FIG. 1 is a plan view seen from the subject side when assembled into a camera. FIG. 1 shows a state immediately after the end of the exposure operation of the rear blade group, and FIG. This shows the state immediately after. FIG. 3 shows a set state of the rear blade group, and FIG. 4 shows a set state of the front blade group. Further, FIG. 5 shows a state during the exposure operation of the front blade group, and FIG. 6 shows a state during the exposure operation of the rear blade group.

First, the configuration of the embodiment will be described. For convenience of explanation, the subject side, that is, the lens side of each component is referred to as the front side, and the image forming side is referred to as the back side. FIG.
FIG. 2 mainly shows the shutter base plate 1 and the rear blade group of the present embodiment. In order to make the configuration easy to understand, the shape of the hidden portion of the shutter base plate 1 is shown by a broken line, and the rear blade group is shown. Are hidden by a dashed line. The shutter base plate 1 is made of a synthetic resin, and has an opening 1a at a substantially central portion thereof, and two arc-shaped long holes 1b and 1c formed at a left side region thereof. .
As is well known, cushion members 2 and 3 made of butyl rubber and having a C-shaped plane are attached to the lower ends of the long holes 1b and 1c.

At four corners of the shutter base plate 1, holes 1d, 1e,
1f, 1g, and 1h are formed. Hole 1 of these
Reference numerals d, 1e, and 1f denote holes for attachment to the camera body.
In addition, an engaging portion 1 is provided at a vertical position on the right side of the shutter base plate 1.
i, 1j are formed. Further, shafts 1k and 1m are provided upright on the front side of the shutter base plate 1. The shafts are also provided upright on the rear side concentrically with the shafts 1k and 1m. However, since it is unlikely that confusion will occur in particular, these shafts are also denoted by the same reference numerals as those on the front surface side. I will explain. A driving member for the front blade and a driving member for the rear blade are rotatably mounted on the front surface side of the shafts 1k and 1m, and the respective driving pins penetrate through the slots 1b and 1c and protrude to the rear side. However, since their configurations are well known, they are not shown.

A counterbore 1n is formed on the back side of the shutter base plate 1 so as to surround the opening 1a as is well known. In addition, a region on the right side of the opening 1a is formed as a thick portion 1p, and has a surface raised from the reference surface on the back side. In the upper left corner of the shutter base plate 1,
A cylindrical shaft 1q having a screw hole and a spacer 1r are formed, and a cylindrical shaft 1s having a screw hole is also provided at the lower left corner.
A spacer 1t is formed. Further, shafts 1u and 1v are erected at the left side of the opening 1a, and a rail-shaped restraining strip 1w is formed as a thick part by integral molding. Further, in the shutter base plate 1, in addition to the restraining strip 1w, three restraining strips 1x, 1y, and 1z are similarly formed.

As described above, among the four restraining strips formed on the shutter base plate 1, the three restraining strips 1w, 1x, 1y are arc-shaped, but all of them are the shafts 1m, 1v.
Is formed so as not to be an arc centered at.
Further, although it cannot be understood from FIG.
1 is formed so that at least the lower part in FIG. 1 gradually increases in thickness from the upper side to the lower side, and the surface of the upper end part becomes gradually thinner. Of the reference plane. Further, the other three restraining strips 1x, 1y, 1z have their respective lower surfaces locally sloped, and their lower end surfaces coincide with the reference surface on the back side of the shutter base plate 1. Has become. In addition, the thickness of the restraining strip 1z other than that is substantially the same as the thickness of the thick portion 1p.

With the above description, the structure of the shutter base plate 1 has been described. Hereinafter, members to be mounted on the rear side of the shutter base plate 1 and the mounting structure thereof will be described. However, the overall configuration on the back side will be briefly described. Shutter base plate 1
On the back side, an intermediate plate and an auxiliary main plate are sequentially attached at a predetermined interval, and in this embodiment, the space between the shutter base plate 1 and the intermediate plate is a blade chamber of a rear blade group. The space between the intermediate plate and the auxiliary ground plate is a blade chamber of the front blade group. An opening similar to the opening 1a of the shutter base plate 1 is formed substantially at the center of the intermediate plate and the auxiliary base plate. An opening is formed. The auxiliary base plate of the present embodiment will be described later in detail, but the intermediate plate does not require a special characteristic configuration, so that illustration and detailed description thereof are omitted.

The structure of the rear blade group will be described first with reference to FIG. The rear blade group includes two arms 4, 5 and four blades 6, 7, and
8, 9 and the most advanced pivoted blade 9
Are slit forming blades. And arm 4,
Numerals 5 are rotatably attached to the shafts 1m and 1v of the shutter base plate 1, respectively. The arm 4 is formed with a long hole 4a, into which a driving pin of the above-mentioned rear blade driving member (not shown) is fitted.

The respective pivotal structures of the two arms 4, 5 and the four blades 6, 7, 8, 9 are the same as in the prior art. 5 and the blades 6, 7, 8, 9 are inserted into the predetermined holes formed from the arms 4, 5 side, and the inserted ends are fixed to the blades 6, 7, 8, 9 by caulking. I have. Then, the arms 4 and 5 have the shutter base plate 1 more than the blades 6, 7, 8 and 9.
, The heads of the connecting shafts protrude from the arms 4 and 5 toward the shutter base plate 1 side.

Here, it is well known that the reason why the thick portion 1p exists is described. As described above, the rear blade group is arranged between the intermediate plate (not shown) and the shutter base plate 1. For this reason, the interval between the intermediate plate and the shutter base plate 1 is set at the left position of the shutter base plate 1 in order to attach the blades 6, 7, 8, and 9, the thickness of the arms 4, 5, and the mounting of each blade. Must be determined in consideration of the amount of protrusion of the head of the connecting shaft.

However, if the distance between the intermediate plate and the shutter base plate 1 is made equal on the basis of this fact, only the blades 6, 7, 8, 9 are present at least on the right side of the opening 1a. It is too large, and the blade is easily displaced or bent in the optical axis direction. for that reason,
In many cases, a member called a blade holding plate is arranged at a position on the right side of the blade so as to reduce the interval. The thick portion 1p is formed by integral molding. However, the present invention does not form the thick portion 1p,
It is also possible to apply to a case where such a blade holding member is arranged.

Next, the configuration of the front blade group and the auxiliary base plate arranged on the back side of the intermediate plate will be described. FIG. 4 shows a state in which the shutter base plate 1, the rear blade group, and the intermediate plate are removed,
It shows a set state of the front blade group. The auxiliary base plate 10 of the present embodiment is made of a synthetic resin similarly to the shutter base plate 1, and has the opening 10a already described substantially at the center. Further, two arc-shaped long holes 10b and 10c and circular holes 10d, 10e, 10f and 10g are formed in a region on the left side of the opening 10a.
Among them, the holes 10e and 10f correspond to the shaft 1 of the shutter base plate 1.
Holes at which the tips of m and 1v are fitted are not shown, but such holes are also formed for the shafts 1k and 1u.

In the area on the right side of the opening 10a, two shafts 10h and 10i are erected.
j, 10k are formed. And the shafts 10h, 10
i has a large diameter portion, a medium diameter portion, and a small diameter portion from the base side. Also, by surrounding three sides of the opening 10a,
A counterbore portion 10m is formed, and a thick portion 10n is formed in a region on the right side of the opening 10a. The thick portion 10n protrudes to the surface side opposite to the thick portion 1p, and has the same role as the above-described thick portion 1p with respect to the front blade group described later with respect to the rear blade group. are doing.

Also, from the left side to the lower side of the opening 10a, four rail-shaped restraining strips 10p, 10q, 10r, 10s are provided.
Are formed as a thick part by integral molding. Of these, the three restraining strips 10p, 10q, 10r are arc-shaped, but they are formed so as not to be arcs centered on the axes 1k, 1u. Further, although it cannot be understood from FIG.
p, 10q, 10r, and 10s are formed so that at least the lower part in FIG. 4 gradually increases in thickness from above to below, and the surface of the upper end portion is
It gradually becomes thinner, and matches the reference surface on the front side of the auxiliary base plate 10.

The front blade group includes two arms 11, 12,
Four blades 1 pivoted to them via a well-known connecting shaft
3, 14, 15, and 16, and the blade 16 is a slit forming blade. And this front blade group is arranged so that the above-mentioned rear blade group is turned over,
The two arms 11, 12 are on the auxiliary base plate 10 side, and the blades 13, 14, 15, 16 are on the intermediate plate side (not shown). Accordingly, the head of each circular connecting shaft protrudes from the arms 11 and 12 toward the auxiliary base plate 10. The arms 11 and 12 are connected to the shaft 1 of the shutter base plate 1.
k, 1u rotatably attached to the arm 11
A driving pin of a driving member for a leading blade (not shown) is fitted into the long hole 11a.

Here, a method of assembling the present embodiment will be briefly described. First, as shown in FIG. 1, the arms 4 and 5 of the rear blade group are attached to the shafts 1m and 1v of the shutter base plate 1, and then two holes of the intermediate plate (not shown) are connected to the shaft 1q of the shutter base plate 1. , 1s. Next, the arms 11 and 12 of the front blade group are attached to the shafts 1 k and 1 u of the shutter base plate 1. Thereafter, the middle diameter portions of the shafts 10h and 10k of the auxiliary base plate 10 are fitted into holes of the intermediate plate (not shown), and the small diameter portions at the tips are fitted into the holes 1g and 1h of the shutter base plate 1. At this time, the tips of the shafts 1m and 1v of the shutter base plate 1 are simultaneously fitted into the holes 10e and 10f of the auxiliary base plate, and
The tip of 1u is also fitted into each hole not shown.

On the right side of the shutter base plate 1 and the auxiliary base plate 10, hook portions 10j and 10j of the auxiliary base plate 10 are provided.
k is hooked on the engaging portions 1i and 1j of the shutter base plate 1, and two screws (not shown) are inserted into the holes 10d and 10g from the rear side of the auxiliary base plate 10 on the left side.
It is screwed to the shafts 1q and 1s of the shutter base plate 1. In addition, the method of attachment by such hooking and screwing is equivalent to the case described in the above-mentioned Japanese Patent Application Laid-Open No. 10-133255. In the assembled state, the distance between the shutter base plate 1 and the auxiliary base plate 10 is regulated by the spacers 1r and 1t and the shafts 10h and 10i, and the intermediate plate (not shown) is fixed. is not.

Next, the operation of this embodiment will be described. 1 and 2 show a state immediately after the end of the exposure operation. At this time, the front blade driving member (not shown) rotatably attached to the shaft 1k on the front side of the shutter base plate 1 includes:
The rotation of the driving pin in the clockwise direction is prevented by the contact of the driving pin with the buffer member 2. Therefore, the arm 11
Are also rotated clockwise by the driving pins, and the four blades 13, 14, 1 of the leading blade group are also rotated.
5 and 16 are superimposed and stored below the exposure aperture. The arm 11 is provided with the restraining strips 10p, 10q, 10
r, and at least one of the slit forming blades 16 is in contact with the restraining strip 10s.

On the other hand, the rear blade drive member (not shown) rotatably mounted on the shaft 1 m on the front side of the shutter base plate 1 rotates clockwise by the drive pin abutting on the buffer member 3. , The arm 4 is also rotated clockwise by its drive pin, and the four blades 6, 7,.
8 and 9 are developed to cover the exposure aperture. And
Since the restraining streak 1w is formed so that the lower part is thicker than the upper part, the four blades 6, 7, 8, 9 are moved via the arm 5 to the intermediate plate side (not shown). Pressing. For this reason, the overlapping state of the blades and the overlapping state of the blades 6 and the intermediate plate become denser, and light leakage from the overlapping portion hardly occurs.

In the state shown in FIGS. 1 and 2, when the film is wound up, the shutter is set in conjunction therewith. As a result, first, the above-mentioned leading blade driving member is rotated counterclockwise against the urging force of the leading blade driving spring (not shown). As a result, the drive pin fitted into the hole 11a rotates the arm 11 counterclockwise, so that the four blades 13, 14, 15, 1
6 are operated upward while reducing the amount of mutual overlap.

Thereafter, the slit forming blades 16 of the front blade group
When the overlapping amount of the rear blade group and the slit forming blade 9 of the rear blade group reaches a predetermined amount, the rear blade driving member is moved counterclockwise against the urging force of the rear blade driving spring (not shown). Start to be rotated. Therefore, the drive pin fitted in the hole 4a rotates the arm 4 in the counterclockwise direction, so that the four blades 6, 7, 8, 9 of the rear blade group increase the mutual overlapping amount. It is operated upward.

As described above, since the leading blade group and the trailing blade group have many pivots with tolerances, the arms and the blades move in the axial direction of the optical axis during the set operation. It is easy to displace. Therefore, when such displacement occurs, in the case of the front blade group, the arm 11 is
The arm 12 slides on the p, 10q, 10r, and the arm 12 slides on the restraining strip 10p, 10q, so that the displacement thereof is suppressed. In the case of the rear blade group, the arm 4
Are in sliding contact with the restraining strips 1w, 1x, 1y, and the arm 5 is in sliding contact with the restraining strips 1w, 1x to be restrained.

Moreover, in the case of the present embodiment, the arc-shaped restraining strips 10p, 10q, 10r are formed so as not to be arcs centered on the axes 1k, 1u.
Also, since the restraining strips 1w, 1x, 1y are also formed so as not to form an arc centered on the axis 1m, 1v, the sliding contact portion of each arm with respect to these restraining strips will gradually change. Each arm is less likely to be damaged due to wear or the like, as compared with a configuration in which the same portion always slides.

The same can be said for each blade, and the blades 13, 14, 15, 16 of the front blade group
In the case of, there is a possibility that at least there is a sliding contact with the restraining strip 10s. In the case of the blades 6, 7, 8, 9
At least there is a possibility of sliding contact with the restraining strip 1z, so that the displacement of each blade can be restrained. In these cases, too, the restraining strips 10s, 1z do not coincide with the operating direction of each blade. As a result, the sliding contact portions of the blades with respect to the restraining strips gradually change. Therefore, each blade is less likely to be damaged by wear or the like.

In this way, the set operation is performed, and the four blades 13, 14, 15, and 16 of the front blade group are deployed to completely cover the exposure opening, and the four blades of the rear blade group.
At the stage where the blades 6, 7, 8, 9 are superimposed and stored at a position above the exposure opening, the rotation of each drive member (not shown) is stopped, and the set operation is completed.
The set state of the rear blade group is shown in FIG.
The set state of the front blade group is shown in FIG. In this embodiment, in this set state, the arms 4 and
5 can not contact the restraining strip 1w, but by changing the trajectory of the circular arc, the restraining strip 1w can be formed to be long upward so that the arms 4 and 5 can be in contact with each other. Alternatively, the restraining strip 10p may be formed to be long upward so that the arm 12 can also be in contact therewith.

When the release button of the camera is pressed in such a set state, first, a driving member (not shown) for the front blade is rotated clockwise, and the driving pin rotates the arm 11 clockwise. Then, the first blade group is exposed. Therefore, the four blades 1 of the front blade group
3, 14, 15 and 16 are formed by the slit forming edge of the slit forming blade 16 while increasing the mutual overlapping amount.
The exposure opening is opened, but this operation is performed by a strong urging force of a driving spring for the front blade (not shown).
Arms 11 and 12 and blades 13 and 1 with respect to the axial direction of the optical axis
The displacements of 4, 15, and 16 are not the ratio at the time of setting, but may be bent. However, also in this case, the displacement and the bending are suppressed by the restraining strips 10p, 10q, 10
r, 10s, and the arms 11, 12, and the blades 13, 14, 15, 1, 1 depending on their shapes.
6 is hardly damaged.

In the case of this embodiment, when the state shown in FIG. 5 is reached, the restraining strips 10p, 10q, 10
By r and 10s, the front blade group is braked. That is, as already described, the restraining strip 10p,
Since the thicknesses of 10q, 10r, and 10s are formed so as to increase as they go downward, the arms 11,
12 is displaced toward the intermediate plate (not shown),
This is because 3, 14, 15, and 16 are pressed against the intermediate plate. After that, the leading blade group stops when the driving pin of the leading blade driving member (not shown) comes into contact with the buffer member 2, but the restraining strips 10 p, 10 q, 10 r, and 10 s
The effect of suppressing the displacement and bending of the front blade group caused by the impact at this time is also exhibited.

In this embodiment, the four restraining strips 1
Although all of 0p, 10q, 10r, and 10s are formed such that the thickness increases as they go downward, the shape may be adopted only in a predetermined length range of the lower part. However, in some cases, it may be used only for some of the restraining strips. When it is not necessary to obtain the braking effect by the restraining strip, it is needless to say that such a shape need not be adopted. Then, in this case, if the thickness of the suppressing strip 10p is formed so as to become thicker as it goes upward, similar to the case of the rear blade group, in the state where the exposure opening is covered, the mutual width of the blades is reduced. It is possible to make the overlapping portions and the like close together.

As described above, when a predetermined time has elapsed since the start of the exposure operation of the front blade group, the rear blade driving member (not shown) is rotated clockwise, and the driving pin is moved to the arm. 4 is rotated clockwise to cause the rear blade group to perform an exposure operation. Therefore, the four blades 6, 7, 8, and 9 of the rear blade group close the exposure aperture by the slit forming edge of the slit forming blade 9 while reducing the amount of mutual overlap. The state immediately after the start of the operation is shown in FIG.
Is shown in

Since the exposure operation of the rear blade group is performed by a strong urging force of a rear spring driving spring (not shown), similarly to the case of the front blade group, the arms 4 and 5 and the blades 6 and 6 are exposed. 7, 8, and 9 attempt to be greatly displaced or bent, but also in this case, the displacement and bending are suitably suppressed by the restraining strips 1w, 1x, 1y, and 1z, and depending on their shapes. Arms 4, 5 and blades 6, 7,
8, 9 are hardly damaged.

In the case of the present embodiment, the thickness of the restraining strip 1w is formed so as to increase as it goes downward, so that braking is applied in the same manner as in the case of the front blade group. Has become. After that, the rear blade group stops when the drive pin of the rear blade drive member (not shown) comes into contact with the buffer member 3, but the restraining streak 1 w prevents the rear blade group from being displaced or bent due to the impact at this time. Also exerts a suppressing effect. Thus, the state in which the exposure operation has been completed is the state shown in FIG. 1 for the rear blade group, and is the state shown in FIG. 2 for the front blade group.

In addition, in the case of the restraining strip 1w as well, the thickness is formed so as to increase as it goes downward, but the shape may be adopted only in a predetermined length range of the lower part. When it is not necessary to obtain a braking effect by the restraining strip 1w, or when it is not necessary to improve the adhesiveness of the overlapping portion of the blades when covering the exposure opening, it is not necessary to adopt such a shape. Further, in the present embodiment, both the shutter base plate 1 and the auxiliary base plate 10 are made of synthetic resin, and the restraining strip is formed on both of the base plates. However, it is prevented that only one of the base plates is formed. Not something.

[0043]

As described above, in the present invention, in order to prevent the arms and blades constituting the blade group from being displaced or bent in the axial direction of the optical axis during operation. A rail-shaped restraining strip is formed thickly by integral molding on a synthetic resin base plate, and the shape of the restraining strip is such that different portions of the arms and the blades can slide in contact with the operation of the blade group. Therefore, it has a feature that the arm and the blade are hardly damaged.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment viewed from a subject side, that is, a photographing lens side, and shows a state immediately after the end of an exposure operation of a rear blade group.

FIG. 2 is a plan view of the embodiment showing a state immediately after the end of the exposure operation of the front blade group.

FIG. 3 is a plan view of the embodiment showing a set state of a rear blade group.

FIG. 4 is a plan view of the embodiment showing a set state of a front blade group.

FIG. 5 is a plan view of the embodiment showing a state during the exposure operation of the front blade group.

FIG. 6 is a plan view of the embodiment showing a state during the exposure operation of the rear blade group.

[Explanation of symbols]

1 Shutter base plate 1a, 10a Opening 1b, 1c, 4a, 10b, 10c, 11a Slot 1d, 1e, 1f, 1g, 1h, 10d, 10e, 10
f, 10g hole 1i, 1j engaging part 1k, 1m, 1q, 1s, 1u, 1v, 10h, 10i
Shaft 1n, 10m Counterbore 1p, 1n Thick 1r, 1t Spacing 1w, 1x, 1y, 1z, 10p, 10q, 10r, 1
0s Suppression strip 2,3 Buffer member 4,5,11,12 Arm 6,7,8,9,13,14,15,16 Blade 10 Auxiliary base plate 10j, 10k Hook

Claims (4)

[Claims] 1. A front blade group and a rear blade group are separately arranged in two blade chambers formed by dividing two ground plates with an intermediate plate, and each blade group is located in a side region of the exposure opening. It is composed of two arms pivotally attached to one of the two base plates, and a plurality of blades pivotally supported on the two arms in order using a connecting shaft of a rivet member, and at least one of the blade groups The two arms are arranged closer to the main plate forming the blade chamber of the blade group than the plurality of blades, and protrude from the head of the connection shaft, and the blade chamber of the blade group is The ground plate formed is made of a synthetic resin, and is provided with a restraining strip which can slide on at least one of the two arms when the blade group is operated, in an arc shape not concentric with the rotation center of the arm. A camera characterized by being integrally molded as a thick part Focal plane shutter. 2. The method according to claim 1, wherein one or more of the restraining strips is provided in a side area of the exposure opening pivotally connected to the two arms, and the one blade group covers the exposure opening. 2. The focal plane shutter for a camera according to claim 1, wherein the region is formed so that a thickness thereof is gradually increased in an operation direction thereof. 3. A front blade group and a rear blade group are separately arranged in two blade chambers formed by dividing two ground plates by an intermediate plate, and each blade group is located in a side area of the exposure opening. It is composed of two arms pivotally attached to one of the two base plates, and a plurality of blades pivotally supported on the two arms in order using a connecting shaft of a rivet member, and at least one of the blade groups The base plate forming the blade chamber is made of a synthetic resin, and the base plate is provided with at least one restraining strip that allows the blades on the base plate side to slide when operating, and slides with a different part of the blade as the operation proceeds. A focal plane shutter for a camera, which is integrally formed as a thick portion in a shape that can be in contact with the camera. 4. The one-blade group is a front-blade group, and the restraining streak stores the side area of the exposure opening where the two arms are pivotally attached and the plurality of blades in an overlapping manner. And at least one of them is provided with at least one restraining strip in at least the final region of the exposure operation so that the thickness gradually increases in the operation direction. 4. The focal plane shutter for a camera according to claim 1, wherein the focal plane shutter is formed by molding.