JP3220823B2 - Blade support device for focal plane shutter for camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade supporting device for a focal plane shutter for a camera.

[0002]

2. Description of the Related Art A focal plane shutter of a type in which two sets of shutter blades supported by arms constituting a parallel link and divided into a plurality of sections are operated by different displacement amounts to sequentially open and close openings. Have
In a single-lens reflex camera in which a photographed image is observed through a finder disposed at the top of the camera through a photographing lens, a shutter blade that is folded above the camera when an exposure operation is performed is located directly below the finder.

[0003] The blades of such a focal plane shutter are rotatably connected to an arm by a pivot pin, and the movement trajectory of the pivot pin passes through the shutter opening during the exposure operation. That is, a connection portion between the slit forming blade and an arm closest to an exposed slit of the slit forming blade,
The distance between the position where the substrate pivotally supports the arm is R, the diameter of the largest portion of the outer diameter of the connection shaft is 2 × r, and the position where the substrate pivotally supports the arm and any position within the shutter opening. Assuming that the distance to the point is L, R ≧ L or R + r ≧ L
Will be satisfied.

[0004]

When the movement locus of the pivot pin passes through the shutter opening during the exposure operation,
Since the pivot pin is not constrained in the shutter optical axis direction in the shutter opening, a large vibration is generated, the light shielding property is reduced, and the flatness and parallelism of the slit side formed by the slit blade are disturbed and the exposure performance is reduced. Was getting upset. In particular, the latter tendency is remarkable in the case of a pivot pin close to the slit side, and the light shielding property before and after the exposure operation may be reduced. Further, when the movement trajectory of the pivot pin passes through the shutter opening and retreats from the shutter opening again, the opening edge of the shutter opening collides with the pivot pin, thereby impairing the durability of the shutter. I was Further, in order to avoid such collisions, a relief portion has been processed around the opening of the substrate.

From the viewpoint of improving the exposure performance, 1/40
There is also a demand for realizing a high-speed time of 00 seconds or 1/8000 seconds or more, and in order to reduce the weight of the shaft support pin, a hole penetrating front and back into a shaft support pin of a subsequent covering blade following the slit forming blade. However, when the movement trajectory of the pivot pin passes through the shutter opening, there is a possibility that exposure from other than the slit side may be performed. A through hole could not be provided. Also, in order to achieve high-speed stability, a so-called link width expansion method of increasing the length of the vertical link of the parallel link mechanism on the slit blade is also effective for maintaining the parallelism of the slit side. However, since the slit side of the slit blade is located almost entirely within the shutter opening when the blade group is operated, the method is limited and not sufficient.

[0006]

According to the present invention, in order to solve the above problems, a substrate having a shutter opening, a group of open and closed shutter blades for opening and closing the shutter opening, and one end rotatable with respect to the substrate. is supported, in the camera focal plane shutter comprising a plurality of arms which a slit forming blade for forming the exposed slit linked supported by pivotally connecting shaft, constitute a parallel link mechanism of the blades, the While the connecting shaft is a hollow shaft,
The distance from the pivot of the arm to the connecting shaft is R,
The diameter of the largest portion of the outer diameter of the connecting shaft is 2 × r,
Distance from any point in the aperture to the pivot of the arm
Is L, the configuration satisfies R + r ≦ L.

[0007]

An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 to 3 are an exploded perspective view and a side view showing an embodiment of a focal plane shutter according to the present invention. In FIG. 2, the film 8 loaded in the camera
A shutter opening 1a is formed in the substrate 1 disposed in front of the camera 1 and on the side of the taking lens 12. In FIG. 1, an open shutter blade group 3 for opening a shutter opening 1a is placed on a substrate 1.

The open shutter blade group 3 is constituted by slit forming blades 3a and cover blades 3b, 3c, 3d, and is rotatably supported by arms 9, 10 forming a pair of parallel links. Specifically, FIG. 6 shows a part of the cross section. FIG. 6 is a sectional view of the shaft support,
2 shows a state in which the slit forming blade 3a is connected to the arm 10 by the shaft support pin 21 having a and reduced weight. Similarly, the covering blades 3b, 3c, and 3d, and the closed shutter blade group 5 described later also have arms 9, 10, and 1, respectively.
9 and 20 are connected. Slit forming blades 3a, 5a
Of the cover blades 3b, 3c, 3d, 5b, 5c, and 5d, at least one of the blades approaching the other blade or arm has an embossed shape that gives a "C" -shaped cross section to the fitting portion of each pivot pin. Processing is performed to reduce the sliding resistance between the cover blades.

A partition plate 4 having a shutter opening 4a is mounted on the open shutter blade group 3, and a closed shutter blade group 5 is mounted on the partition plate 4. Similar to the open shutter blade group 3, the closed shutter blade group 5 is rotatably supported by slit-formed blades 5a and cover blades 5b, 5c, 5d, respectively, by arms 19, 20 forming a pair of parallel links. . A receiving plate 7 having a shutter opening 7a is mounted on the closed shutter blade group 5.

In this manner, the open shutter blade group 3, the partition plate 4, and the closed shutter blade group 5 are incorporated in the substrate 1 and the receiving plate 7 is attached by a known method. That is, as shown in FIG. 2, the substrate 1 located on the photographing lens 12 side,
The receiving plate 7 located on the film 8 side constitutes a storage chamber for the shutter blade group, the closed shutter blade group 5 is located on the film surface 8 side, and the open shutter blade group 3 is located on the taking lens 12 side. The partition plate 4 is interposed between the group of open shutter blades 3 and the group of closed shutter blades 5.

Here, the group of open shutter blades 3 and the group of closed shutter blades 5 are slit-forming blades 3 in the embodiment shown in FIG.
a, 5a, cover blades 3b, 3c, 3d and 5b, 5c,
5d are superimposed. However, each of the open and closed shutter blade groups 3 and 5 may be one large slit forming blade.

The arm 9 is rotatably mounted on the substrate 1 via a pin 1b, and the arm 10 is rotatably mounted on the substrate 1 via a pin 1c. In the pin 1c, the distance L between the pin 1c and an arbitrary point in the shutter opening is larger than the distance R to the center of the pivot pin 21 that connects and supports the slit forming blade 3a with the arm 10. It is located in a place. That is, as shown in FIG.
When a circle passing through the pivot pin 21 at the connection portion with the slit forming blade is drawn, the shutter opening 1a is outside the circle. Further, by configuring the pivot support pin so that the maximum outer shape is not located in the shutter opening 1a, light leakage does not occur even if the hole 21a is provided in the pivot support pin 21 as shown in FIG. That is, the maximum portion of the outer shape of the pivot pin 21
2 × r diameter, pin 1c and any point in shutter opening
Is defined as a position satisfying R + r ≦ L.
ing. Further, a hollow shaft is used as the shaft support pin 21,
Vibration in the shutter optical axis direction due to weight reduction of the pivot pin 21
Quickly converge. The connecting portion closest to the slit side of the slit forming blade, that is, the pivot pin 21 is connected to the shutter opening 1a.
Even if the other pivot is located inside the shutter opening, the subsequent covering blades can cover the pivot, so there is no restriction on the position of the pivot 1b of the substrate of the arm 9 and there is no hole in the pivot pin. Can be provided.

Arms 19 and 20 are arms 9 and 1 respectively.
0, and attached to pins 1d and 1e. Pin 1e
Is in the same positional relationship as the pin 1c with respect to the shutter opening 1a. FIG. 4 shows an embodiment of such a drive unit of the opening and closing shutter blade groups 3 and 5. As shown in FIG. 4, the drive unit is a group of open and closed shutter blades 3,
5, an opening lever 30 and a closing lever 50 for rotating each arm, these are set to predetermined set positions shown in the figure, and a set lever 6 having cam portions 60a and 60b.
0 and electromagnets 40 and 80 for controlling the opening lever 30 and the closing lever 50, respectively.

The opening lever 30 and the closing lever 50 are urged by drive springs 31 and 51 to rotate leftward about shafts 32 and 52, respectively.
The speed of the shutter blades can be adjusted by adjusting the spring forces of 1, 51. The set lever 60 is urged by a spring 61 so as to rotate clockwise about an axis 62.
It is driven by 0 and turns left. In such a driving unit, at the time of the setting operation, the set lever 60 is turned to the left, and the rollers 33 and 53 of the opening lever 30 and the closing lever 50 are pressed by the cam parts 60a and 60b.
Then, the closing lever 50 is turned clockwise. Thereby, the iron pieces 3 respectively fixed to the opening lever 30 and the closing lever 50
4 and 54 are pressed against the iron cores 41 and 81 of the electromagnets 40 and 80, and the electromagnets 40 and 8 are formed by a known electric circuit (not shown).
When 0 is excited, it is configured to be attracted to the iron cores 41 and 81. Since the standby position of the shutter blade group changes depending on the positions of the iron cores 41 and 81, a locking portion 81a is provided on the iron core 81 to determine the relative position between the blade group and the substrate 1. Stopper 8 that engages with the stop
2 is provided integrally with the substrate 1.

The operation of the above configuration will now be described. First, the charging member 90 of the camera is operated in conjunction with the film winding operation to rotate the set lever 60 counterclockwise, and the shutter is set by the setting operation. In this state, all the connecting portions between the arm and the blade are outside the shutter opening 1a, and the slit forming blade 3
The positions of a and 5a are regulated in the direction of the optical axis with respect to each other via the pivot pin, the gap between the respective blades is narrowed, and the light shielding property is improved.

When a shutter release operation is performed in this state, the electromagnets 40 and 80 are first excited to open and close the open / close lever 3.
0 and 50 are attracted to the electromagnets 40 and 80 via the iron pieces 34 and 54. Next, when the charging member 90 of the camera is retracted, the set lever 60 is turned clockwise by the spring 61. Thereafter, the electromagnets 40 and 80 are sequentially demagnetized and the opening lever 30 is turned leftward, so that the slit forming blades 3a and the cover blades 3b, 3c and 3d of the open shutter blade group 3 move to the upper ends and start opening the shutter opening 1a.

When the open shutter blade group 3 is opened and the electromagnet 80 is demagnetized after a predetermined time has elapsed and the closing lever 50 turns left, the slit forming blade 5a and the cover blades 5b, 5c, 5d of the closed shutter blade group 5 are moved. It moves to the upper end in FIG. At this time, even if the slit forming blade 3a reaches the vicinity of the center of the shutter opening 1a, the pivot pin 21 is located in the substrate 1, and the movement of the pivot pin in the optical axis direction is constantly regulated by the substrate 1, and further, the pivot pin is further restricted. A hollow shaft is used as 21
Vibration in shutter optical axis direction
And the open shutter blade group 3 operates stably.
Similarly, the closed shutter blade group 5 can operate stably. Also, since the pivot pin 21 is located in the substrate 1,
Light leakage from the through hole 21a of the pivot pin 21
There is no.

An exposure slit is formed by the slit side P at the rear end of the slit forming blade 3a of the open shutter blade group 3 and the slit side Q at the front end of the slit forming blade 5a of the closed shutter blade group 5. Even when the slit sides P and Q reach the vicinity of the upper end of the shutter opening 1a, the pivot pin 21 is located in the substrate 1, so that the slit forming blade 3a is formed in the same manner as the lower end and the center. 5a is pressed by the substrate 1 and the receiving plate 7 in the optical axis direction via the pivot pin, so that the distance between the slit forming blades does not increase. FIG. 5 illustrates this configuration.

As shown in FIG. 5, when the open and closed shutter blade groups 3, 5 move from the lower end to the upper end, the interval between the slit forming blades 3a, 5a in the optical axis direction at the lower end portion is small, and parallel light beams are generated. The difference between the exposure range D3 and the exposure range d3 for oblique rays is small. Also at the upper end, the distance between the blades forming the slits of the open shutter blade group 3 and the closed shutter blade group 5 in the optical axis direction is narrow, and the difference between the exposure range D4 for parallel rays and the exposure range d4 for oblique rays is small. . Therefore, the difference between D3 / d3 and D4 / d4 is small,
The difference in the exposure amount between the lower end and the upper end is reduced.

In the above description, the case where the exposure slit travels from the lower end to the upper end has been described. However, the present invention can be similarly applied to the case where the exposure slit travels from the upper end to the lower end . In addition, the shaft supporting pin 2
Since 1 is always in the substrate 1, it does not collide with the upper edge of the shutter opening 1a.

With the above configuration, as shown in FIG. 7, the pivot pin 21 is disposed at an extension of the slit side P of the slit forming blade 3a, and the blade 3a and the arm 10 are connected to the slit side P.
Even if it is formed on the front side in the advancing direction, it does not fall within the range of the shutter opening, so that the exposure performance is not affected. Therefore, the distance between the pins 1b and 1c which is the width of the parallel link can be increased. The same applies to the slit forming blade 5a,
The distance between the pins 1d and 1c can be increased. On the contrary, the arm 9 is arranged above and the arm 19 is arranged below, and the distance between the pins 1b and 1c, which is the width of the parallel link, the pins 1d and
The distance between c can be increased.

[0022]

A configuration in which the motion trajectory of the connecting shaft when exposure operation according to the present invention does not pass through the shutter opening, the hollow shaft connecting shaft
Therefore, the weight of the connecting shaft has been reduced,
The vibration quickly converges. For this reason, it is possible to prevent the flatness and parallelism of the slit sides formed by the slit blades from being disturbed and thereby causing a disturbance in the exposure performance, and to prevent a decrease in light shielding properties before and after the exposure operation .

In order to realize a high speed time, a so-called link width expansion method of increasing the length of the vertical link of the parallel link mechanism on the slit blade is also known as an extension of the slit side of the slit blade. This is possible because a pivot point can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a side sectional view of a main part showing an embodiment of the present invention.

FIG. 3 is a plan view of a main part showing an embodiment of the present invention.

FIG. 4 is a plan view of a main part showing an embodiment of the present invention.

FIG. 5 is a side sectional view of a main part showing an embodiment of the present invention.

FIG. 6 is a side sectional view of a main part showing an embodiment of the present invention.

FIG. 7 is a plan view of a main part showing an embodiment of the present invention.

[Explanation of symbols]

 1a Shutter opening 1 Substrate 3 Open shutter blade group 5 Closed shutter blade group 3a Slit forming blade 21 Shaft support pin 10, 20 Arm

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kuni Takahashi, Inventor 934-13 Kadawa, Yotsukaido-shi, Chiba Co., Ltd. Seikosha Co., Ltd. Chiba Works (56) References Japanese Patent Application Laid-Open No. 58) Fields surveyed (Int.Cl. ⁷ , DB name) G03B 9/36

Claims (2)

(57) [Claims] 1. A substrate having a shutter opening, a group of open and closed shutter blades for opening and closing the shutter opening, and a slit rotatably supported at one end by the substrate to form an exposed slit in the group of blades. Rotating the forming blade freely
In a camera focal plane shutter comprising a plurality of arms connected and supported by a connecting shaft and constituting a parallel link mechanism, the connecting shaft is a hollow shaft, and a distance from a supporting portion of the arm to the connecting shaft is R. , The connection
The diameter of the largest part of the outer diameter of the shaft is 2 × r, and the shutter opening
L is the distance from any point within to the pivot of the arm.
Then, a blade supporting device for a focal plane shutter for a camera, wherein R + r ≦ L is satisfied . 2. The blade group opens the shutter opening.
When the connecting shaft is
2. The blade supporting device of a focal plane shutter for a camera according to claim 1 , wherein the blade supporting device is located on a side close to the opening of the shutter.