JPH0524901Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a so-called vertical (vertical) traveling type focal plane shutter for a camera in which a blade divided into a plurality of blades is run in the vertical direction by a parallel link mechanism.

[Background of the invention] In recent years, the market has increasingly demanded higher shutter speeds, and in order to meet this demand, efforts have been made to reduce the mass of the moving blades to reduce the moment of inertia.

These technologies also help reduce the amount of charge required by the shutter.

As a method for reducing mass, for example, Al,
It is conceivable to use lightweight materials such as Ti or plastics, reduce the number of blade segments, and reduce the amount of overlap between adjacent blades (overlapping width).

However, as the polymerization width is reduced, its light-shielding properties become a problem.

FIG. 2 shows such a conventional focal plane shutter.

Reference numeral 1 denotes a substrate, which is provided with an opening window 2.

A known blade group is constituted of a slit-forming blade 3 and first, second, and third light shielding blades 4, 5, and 6, and the width W of each blade is set to be substantially equal to each other.

Each blade is supported by a first arm 7 supported by a shaft 8 and a second arm 9 supported by a shaft 10 via support portions (not numbered) provided respectively.

If the overlapping width of the slit forming blade 3 and the first light shielding blade 4 is L1, and the overlapping parts are L2 and L3, the relationship is L1=L2=L3.

The distance between each blade support part provided on each arm 7, 9 and each shaft 8, 10 (rotation radius of the support position) is:
Settings are made so as to obtain the relationships among the polymerization widths described above.

When a focal plane shutter device with such a configuration is used in a single-lens reflex camera equipped with a reflecting mirror whose upper portion is pivotally supported by a hinge, the upper part of the shutter device is attached to the attachment part of the upper edge of the mirror or By using a light shielding member in combination, it is easy to obtain sufficient light shielding, but on the other hand, the lower part is susceptible to light leakage due to the gap between the lower edge of the mirror and the inner surface of the mirror box due to incident light from the photographing lens side.

In order to prevent this, a technique has been proposed in which the leading blade group is unfolded again at the end of the shutter shooting and is doubled with the trailing blade group to improve light blocking performance. tends to become complicated.

In addition, the problem of light shielding is also caused by the front blade group that closes the opening window when the shutter is not charged.
This applies to both rear blade groups that cover the window when the shutter is in a charged state.

However, considering the recent technological trend in which the number of cameras that charge the shutter immediately after shooting has increased, it would be better to focus on the light-shielding properties only on the spread blade group side when charging the shutter. becomes.

[Object of the invention] The object of the invention is to eliminate the disadvantages of the conventional device described above, and is particularly suitable for cameras that perform shutter charging immediately after the shutter operation is completed. It is an object of the present invention to provide a focal plane shutter for a camera that has sufficient light-shielding properties without complicating its structure.

[Structure of the invention] The object of the invention described above is to provide a substrate having an opening window, a substrate divided into a plurality of (n) pieces, which are spread out so as to have overlapping parts, close the opening window, and close the window area. The light-shielding blade group includes a slit-forming blade that is housed outside, and a support member that supports the blade group and includes a plurality of support members, the width of the slit-forming blade being W1, and the width of the slit-forming blade being W1. The width of each shading blade connected sequentially in the direction away from the blade is
W2 to Wn, so that the relationship W1<W2<...<Wn is established, and when the blade group is spread out to block light above the aperture window, the amount of overlapping portion of each blade (overlapping The overlap width L1 of the blades formed by the slit-forming blade and the shading blade adjacent to the slit-forming blade is the minimum, and gradually increases as the blades move away from the slit blade. This is achieved by making the relationship L1<L2<...<Ln-1.

[Embodiment of the invention] Fig. 1 is a plan view showing an embodiment of the invention, and shows that the shutter is charged immediately after the exposure operation is completed, and the preparation for the exposure operation is completed (shutter charge state). .

In order to make the explanation easier to understand, the explanation will be based on the blade group in the spread state in the drawings, but in this embodiment, it is assumed that the blade group on the superimposed side also has the same configuration.

Reference numeral 1 denotes a substrate which has an arc-shaped elongated hole 1a and an opening window 2 for photographing.

3 is a slit forming blade, the blade width is W1,
The exposure slit is formed in cooperation with the slit forming edge of the slit forming blade of the unnumbered rear blade group.

4 is a first light shielding blade, 5 is a second light shielding blade, 6
is the third light-shielding blade, each blade width W2, W3,
It has W4 and is connected to adjacent blades so that they partially overlap each other.

At this time, the relationship between each width is W1＜W2＜W3＜W4 It is assumed that

In order to prevent the mass of the entire blade group from increasing, it is desirable to set the width W1 of the slit-forming blade 3 narrower than in the conventional example, and to set the width W4 of the third light-shielding blade 6 wider than in the conventional example.

Reference numeral 7 denotes a first arm, which is rotatably supported on the substrate 1 by a shaft 8.

Reference numeral 9 denotes a second arm, which is rotatably supported on the substrate 1 by a shaft 10.

Reference numeral 11 denotes a drive pin, one end of which is connected to a drive mechanism (not shown), the other end of which is engaged with the first arm 7, and which moves in an arc along an elongated hole 1a provided in the substrate. The arm 7 is thereby driven.

In addition, each arm 7, 8 and each blade 3,
The positions of the supporting parts 4, 5, and 6 and the distance relationship from the shafts 8 and 10 are the same as in the conventional example described above.

Since the present invention is configured as described above, the width of the overlapping part (overlapping part) of the slit forming blade 3 and the first light shielding blade 4 is defined as L1, and the overlap width of the overlapping part of other blades is similarly set as L1. Let L2 and L3 be,
Since the relationship between the widths (w) of the blades is set as described above, the relationship between the widths of the overlapping portions is L1<L2<L3.

According to the above-mentioned configuration, in the overlapping state, the edge 3a of the slit forming blade 3 on the opening window 2 side
Compared to this, the edges of the other light shielding blades 4, 5, and 6 on the same side come closer to the window 2, but the relationship of the operating radius when driven by each arm 7, 9 Since the light-shielding blades 4, 5, and 6 are smaller than the slit-forming blade 3, irregular exposure will not occur due to the light-shielding blade running ahead of the slit-forming blade while traveling over the aperture window 2. do not have.

The operation will be briefly explained below.

In the illustrated state, the shutter is charged and ready for exposure operation.

When the shutter is released here, the drive pin 11 rotates clockwise along the elongated hole 1a of the substrate 1 by a drive mechanism (not shown).

The first arm 7 that engages with the drive pin 11 also rotates clockwise about the shaft 8, and the first arm 7 engages with the drive pin 11.
The slit-forming blade 3 and each of the light-shielding blades 4, 5, and 6 supported by the substrate 1 open the opening window 3 while being sequentially overlapped, and move into the storage section provided at the bottom of the substrate 1.

The unnumbered blade group on the overlapping side is
Exposure slits are formed in accordance with the exposure amount, and the slit forming blades 3 that travel first are delayed by a predetermined amount, and the opening is started with the same slit forming blades in the lead, and the aperture window is blocked. It's closing.

After the blade group including the slit-forming blade 3 that traveled earlier opens the aperture window and overlaps, and finishes traveling,
When the group of blades traveling later completely covers the window, one exposure operation ends.

Then, it immediately moves to the shutter charge operation.

A charge mechanism (not shown) causes the drive pin 11 to
When the blade rotates counterclockwise along the elongated hole 1a, the superimposed leading vane group supported by the blade spreads out again with the slit forming blade 3 at the beginning, covering the opening window 2. .

When the light can be sufficiently shielded, the trailing blade group in the unfolded state is rotated counterclockwise by the drive pin and arm, and is superimposed on the substrate 1.
Move to the storage section provided at the top of the.

In this way, the process returns to the exposure preparation state shown in FIG. 1 again.

[Effects of the invention] According to the focal plane shutter for cameras of the invention, the width of the slit-forming blade is made smaller than the width of any of the light-shielding blades, and the width of each light-shielding blade is set away from the slit-forming blade. As a result, when the blade group spreads out and blocks light above the aperture window, the overlapping width of the blade formed by the slit-forming blade and the shading blade adjacent to the slit-forming blade is increased. The overlapping width of the blades formed by adjacent light-shielding blades is made larger than (the amount of overlap), and the overlapping width of the blades formed by adjacent light-shielding blades moves toward the blade in the direction away from the slit blade. As a result, it is possible to obtain good light-shielding properties without making the structure any more complicated than before, especially in vertically traveling camera focal plane shutters in which the blades run vertically. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a plan view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Opening window, 3... Slit forming blade, 4, 5, 6... Shading blade, 7... First arm, 7a, 7b, 7c, 7d... Support part, 9...
...Second arm, 8a, 8b, 8c, 8d...Support part.

Claims (1)

[Claims for Utility Model Registration] A substrate provided with an aperture window that serves as a light path during photographing, and a plurality of (n) pieces that are divided and connected so that some overlap with each other on the window of the substrate. a blade group comprising a slit-forming blade and a light-shielding blade, which are spread out to close the opening window and are stored in an area that does not block the window; a support member consisting of a plurality of pieces rotatably supported on the substrate; and a width of the slit-forming blade is W1, and each light-shielding blade is successively connected in a direction away from the blade. width
W2 to Wn, and set the relationship W1<W2<...<Wn, and when the group of blades is spread out to block light above the aperture window, the amount of overlapping portion of each blade (overlapping The overlap width L1 of the blades formed by the slit-forming blade and the shading blade adjacent to the slit-forming blade is the minimum, and gradually increases as the blades move away from the slit blade. A focal plane shutter for a camera characterized by the relationship L1<L2<...<Ln-1.