JP3456347B2 - Shutter mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter mechanism for a camera that uses a plurality of shutter blades.

[0002]

2. Description of the Related Art A shutter mechanism utilizing shutter blades blocks or opens an optical path from a photographing lens to a film by rotating a plurality of shutter blades in a direction perpendicular to an optical axis. To do.

FIG. 1 shows a conventional shutter mechanism using two shutter blades 1 and 2, and FIG.
It is the bb sectional view taken on the line of (a). FIG. 1 shows the shutter mechanism in the closed state. As shown in the figure, in the conventional shutter mechanism, each shutter blade 1 and 2 is formed of a flat plate. If the two flat plate-shaped shutter blades are arranged in surface contact with each other, smooth rotation is hindered by the frictional force, so it is necessary to provide a slight gap A between them.

However, since such a gap extends in parallel between the shutter blades, it forms an optical path from the front of the shutter mechanism to the rear thereof, which results in light leakage. .

[0005]

SUMMARY OF THE INVENTION Therefore, the technical problem to be solved by the present invention is to provide a shutter mechanism which allows smooth relative movement of shutter blades and does not cause light leakage when the shutter is closed. It is to be.

[0006]

SUMMARY OF THE INVENTION The present invention was devised to effectively solve the above-mentioned problems, and employs shutter blades that can mutually contact only by line contact, and at least a shutter is provided. When closed, the adjacent shutter blades are in line contact with each other. The lines that make up the line contact are the shutter
When the shutter blades start to open,
And extends in a substantially vertical direction.

In the shutter mechanism of the present invention configured as described above, since the adjacent shutter blades are in line contact with each other when the shutter is closed, the optical path from the front to the rear of the shutter mechanism is blocked. . Therefore, it is possible to reliably prevent light leakage when the shutter is closed. When the shutter blades move relative to each other when the shutter is closed and the shutter opens, the adjacent shutter blades move relative to each other without any contact, or even if they move in contact with each other, surface contact occurs. The frictional resistance is sufficiently small because it is not a line contact.

Therefore, in the shutter mechanism of the present invention, it is possible to reliably prevent light leakage when the shutter is closed and to ensure smooth relative movement of the shutter blades.

In the shutter mechanism of the present invention, when two shutter blades are used, one shutter blade may be formed of a flat plate and the other shutter blade may be formed of a curved plate, or both shutter blades may be formed. Is preferably composed of a curved plate. When only one of the shutter blades is composed of a curved plate, at the initial stage when both shutter blades start to move relative to each other from the shutter closed position, both slide while maintaining line contact, but If both shutter blades are composed of curved plates, both shutter blades come into contact only when the shutter is closed,
Since both of them start relative movement and the contact portions are separated from each other to be in a separated state, it is more excellent in smooth relative movement.

Further, the same effect can be obtained by forming one shutter blade with a flat plate and replacing the other shutter blade with a curved plate instead of the curved plate.

[0011]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 2 is a front view illustrating the shutter mechanism of the present invention, and the alternate long and short dash line in the figure indicates the line contact portion. 3 is a sectional view taken along line 3-3 of FIG. 2 and corresponds to FIG. 1 (b).

In this embodiment, one shutter blade 11 is formed of a curved plate having an arcuate cross section, and the other shutter blade 12 is formed of a flat plate. Each shutter blade
The ordinary rotating mechanism (not shown) causes the rotating shafts 11a and 12 to rotate about the rotating shafts 11a and 12a, respectively. That is, each shutter blade is rotated relative to the arrow direction from the closed state shown in FIG. 2 to be in the open state.

Rotation of the shutter blades 11 and 12 in the direction of the arrow in FIG. 2 corresponds to relative movement in the direction of the arrow in FIG. 3, and the contact 15 in FIG. It corresponds to the alternate long and short dash line representing the part. That is, the alternate long and short dash line in FIG. 2 extends perpendicularly to the paper surface through the contact 15 in FIG. In this way, since both shutter blades are physically in contact with each other when the shutter is closed, an optical path from the front to the rear of the shutter mechanism as shown in FIG. 1B is not formed, It is possible to reliably prevent light leakage.

When the shutter blades 11 and 12 start moving relative to each other from the closed position toward the open position, the contact points 15 of the shutter blades 11 and 12 move to the right in FIG. When they cross the portion 12 ', they are separated from each other, and thereafter, they move relative to each other without exerting a frictional force on each other. In this way, when both shutter blades move relative to each other, they are in contact with each other in the initial stage, but since they are line contact rather than surface contact, the frictional force generated between them is sufficiently small and smooth. Relative movement is not hindered. And after the two physically separated,
It rotates smoothly without the influence of frictional force.

FIGS. 4 and 5 show another embodiment of the present invention and are sectional views corresponding to FIG. 3, respectively.

In the embodiment shown in FIG. 4, both shutter blades are composed of curved plates having an arcuate cross section. In this case also, both shutter blades 21 and 22 are closed when the shutter is closed. Make line contact. However, unlike the case of FIG. 3, the shutter blades 21 and 22 are in line contact with each other only when the shutter is closed. That is, in order to open the shutter from this state, both shutter blades start to rotate with respect to each other, and at the same time, both are separated. In other words, both shutter blades do not slide while maintaining line contact. Therefore, the rotation of both shutter blades can be performed more smoothly than in the case of FIG.

In the embodiment shown in FIG. 5, one shutter blade 32 is a flat plate and the other shutter blade 31.
Is a bending plate. That is, in this embodiment, a bent plate is adopted in place of the shutter blade 11 of the curved plate in FIG. The shutter blade 31 includes two flat plate portions 31a, 3a.
1b are formed at an angle to each other,
The ridge portion 31c, which is a boundary between both flat plate portions, constitutes a line contact portion with respect to the flat plate shutter blade 32.

In the embodiments shown in FIGS. 3 to 5, since two shutter blades that are in line contact with each other are used, light leakage is prevented even if the attitude of the shutter blades is different. There is an advantage that the function does not deteriorate. This is specifically shown in FIG. FIG. 6 (a) shows a conventional example in which two flat-plate shutter blades are used.
FIG. 6 (b) shows again the configuration shown in FIG. 4 which is most excellent in this function.

That is, in the case of the conventional example of FIG. 6 (a), for example, when the camera is held downward, if the shutter blades are bent or tilted by their own weight, a gap between the two shutter blades is generated. Partially grows. In this case, the light from the taking lens enters from the lower side of the figure (that is, from the side where the gap becomes larger), so that light leakage is further promoted. On the other hand, in the case of the present invention shown in FIG. 6 (b), even if the shutter blade bends or tilts downward, the line contact position is merely moved, and the physical contact state between them is Since it is maintained, the light leakage prevention function does not deteriorate. Although FIG. 6B illustrates the configuration of FIG. 4, the same applies to the configurations of FIGS. 3 and 5.

Although the embodiment of the present invention has been described with respect to the case where two shutter blades are adopted, the adjacent shutter blades can be brought into mutual contact only by line contact, and by this line contact state, the shutter mechanism extends from the front to the rear. The present invention can be applied to a case where three or more shutter blades are adopted as long as the optical path can be blocked.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram illustrating a conventional shutter mechanism.

FIG. 2 is a front view showing a shutter mechanism of the present invention.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a sectional view showing another embodiment of the present invention and corresponds to FIG.

5 is a cross-sectional view showing still another embodiment of the present invention, which corresponds to FIG.

FIG. 6 is an explanatory diagram for explaining light leakage when a difference in attitude occurs between shutter blades.

[Explanation of symbols]

1 and 2 shutter blades 11, 12 shutter blades Side edge of 12 'shutter blade 11a, 12b Rotation axis 15 contacts 21, 22, 31, 32 shutter blades 25 contacts

Continuation of the front page (56) References JP-A-9-43674 (JP, A) JP-A-60-185933 (JP, A) Jikkoku 41-17254 (JP, Y1) (58) Fields investigated (Int .Cl. ⁷ , DB name) G03B 9/00-9/54

Claims (5)

(57) [Claims] 1. A plurality of shutter mechanism comprising a shutter blade roots, the shutter blade adjacent the shutter
When the shutter blades start to open,
To contact only by line contact extending substantially vertically Te
A shutter mechanism having a simple shape and being in line contact with each other at least when the shutter is closed, thereby preventing light leakage when the shutter is closed. 2. The shutter mechanism according to claim 1, further comprising two shutter blades. 3. The shutter blade on one side is a flat plate (12) and the shutter blade on the other side is a curved plate (11).
The shutter mechanism described. 4. A shutter mechanism according to claim 2, wherein both shutter blades are curved plates (21, 22). 5. The shutter blade on one side is a flat plate (32) and the shutter blade on the other side is a bent plate (31).
The shutter mechanism described.