JPS6226010B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a set of shutter blades including a plurality of arms and a plurality of opaque thin plates, the thin plates being pivotally attached to the arms, and two sets of shutter blades. In a focal plane shutter in which a partition plate is provided between the blades, collision between the slit-forming blade in the so-called rear blade group of the two sets of shutter blades and the edge surface of the mapping window of the partition plate. prevent,
Or it relates to a mechanism that weakens the impact.

Although the conventional focal plane shutter having the above structure is already known, for convenience, it will be briefly described with reference to FIGS. 1 and 2.

In Figure 1, the focal plane shutter is shown in a static state (after exposure), with a portion omitted, and in order to make the drawing easier to read, the horizontal dimensions are enlarged compared to the vertical dimensions ( The same applies to Figures 3 and 4 below), 1 is the main plate of the shutter with the mapping window 1a, and 2 is the window 2.
a, the upper and lower edges of which are formed by slopes 2b and 2c (Fig. 2) to prevent blade collisions, and a partition plate 3 that is set obliquely to the main plate 1, also has a window 3a. Cover plates 4 and 5 are vane holding plates having recesses 4a and 5a, respectively.

6, 7, 8, and 9 are each made of opaque thin plates;
2 whose base parts are pivotally connected to the base plate by respective shafts;
This is a group of leading blades which are pivotally connected to a book opening arm (not shown) and whose free ends run in the vertical direction in FIG. 1 in the space between the blade holding plate 4 and the partition plate 2. . The pivot points between each of the leading blades and each of the opening actuating arms, and the pivot points of the opening actuating arm to the main plate are mutually connected so as to form four vertices of a parallelogram formed by connecting them. Each leading blade is mounted such that the slit forming blade 6 forming one side of the slit is located at the tip of the opening actuating arm and closest to the opening actuating arm, and the other leading blades are The shafts 7 to 9 are arranged so as to be stacked one after another on the slit forming blade, and the shafts to which the shafts are pivoted in the order in which they are stacked approach the main body of the opening operating arm.

Therefore, each of the leading blades 6 to 9 performs a pantograph movement (parallel movement while always maintaining the same posture) with one side fixed. 10, 11, 12,
Reference numeral 13 denotes a group of rear blades, each of which is made of an opaque thin plate and is configured to run in the space between the partition plate 2 and the blade holding plate 5. The trailing blade group is attached to two closing actuating arms (not shown) in an inverted configuration with the leading blade group, and is therefore driven in the same manner.

In addition, in the rear blade group, the slit forming blade 1
3 forms the rear edge of the slit. Further, the above-described mounting structure between the arm and the blade is well known from Japanese Patent Publications No. 19175/1983 and No. 19259/1984, although the number of blades is different.

Next, the operation of the focal plane shutter shown above will be explained. When the shutter charge operation is performed now, the leading blade group will unfold downward from the first position shown in the figure, with the slit forming blade 6 at the top, one on top of the other, as if opening a fan. On the other hand, the hind wings move downward like closing a fan,
When the operation is completed, the device waits in the state shown in FIG. 3.

When the release operation is performed, the leading blades converge upward with the blade 9 at the beginning and the slit forming blade 6 at the end, while the trailing blade group with the slit forming blade 13 at the beginning unfolds. Exposure is performed by moving as if chasing after each other, and the state shown in FIG. 1 is reached. In the above, the role of the diaphragm 2 is to prevent collision between the leading blade and the trailing blade, and the reason why the diaphragm is set diagonally to the main plate 1 is to fulfill the above purpose and at the same time. Even if the amount of overlap between the blades changes, both slit blades 6 and 13
This is to prevent light leakage, variations in exposure amount, etc. by always keeping the distance between the two constant.

The focal plane shutter of the above type has a simple structure, stable operation, and many excellent features. In order to reduce the weight, if a material with low specific gravity such as titanium alloy, aluminum alloy, or plastic is used as the blade material, or if the thickness of the blade is reduced, the rigidity of the blade decreases and the first to
In the conventional type shown in FIG. 3, the slit-forming blade 13 is deflected during the exposure operation, which cannot be prevented by making the edges of the window sloped, causing the slit-forming blade to collapse into the partition plate. 2 window 2a
There was a violent collision with the upper edge of the

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and has been made for the purpose of solving the problems. At the time of exposure, by adding other deformation, a gap is created between the slit forming part of the slit forming blade in the rear blade group and the upper edge of the window of the partition plate (slopes 2b, 2c), or It is an object of the present invention to provide a focal plane shutter in which the impact of collision between an edge and a slit-forming blade is extremely reduced.

The present invention will be described below with reference to drawings (FIGS. 4 to 12) showing embodiments of the present invention.

First, a first embodiment shown in FIGS. 4 to 6 will be described. In these drawings, the structures and operations of the members designated by numerals 1 and 3 to 13 are all the same as those of the conventional example. Since it is the same as that, the explanation will be omitted. 20 is installed between the leading blade groups 6 to 9 and the trailing blade groups 10 to 13 so as to be oblique to the main plate 1, and isolates each blade group from each other, and also between the blade holding plates 4 and 5. is a diaphragm that forms a diagonal gap through which they move.
The partition plate 20 has a mapping window 20a,
Also, slopes 20b and 20 forming the upper edge of the window 20a.
It has a shape in which the base line is near the lower end of c, and the part above it is bent toward the main plate 1 in a substantially "H" shape. (FIG. 5) In the focal plane shutter of this embodiment, during exposure, the rear blade groups 10 to 13 move upward while unfolding from the lower storage position, with the slit forming blade 13 at the beginning. In this case, each trailing blade is regulated by the surfaces 20d, 20e of the diaphragm 20 and each adjacent blade and advances along said surfaces 20d, 20e. At this time, each rear blade is slightly bent, but if this bending phenomenon occurs along the thickness direction of the slit forming blade 13, if the partition plate is flat as in the conventional example, and the upper edge of the window 2a is If 2b and 2c are in contact with the rear blade side surface, then
The upper end of the slit-forming blade may collide with the upper edge surface, but in this embodiment, the window 2 of the partition plate 20
The upper edge surfaces 20b and 20c of 0a on the rear blade side are extended from the surfaces 20d and 20e toward the main plate side.
(FIG. 6), or due to the synergistic effect of this and the fact that the upper edge is sloped, the slit-forming blade 13 collides with the upper edge surfaces 20b and 20c of the partition plate. Without any problem, the blade 13 (and therefore the other rear blades 10 to 12) smoothly move to the illustrated position.

In Figures 7 and 8, Figures 9 and 10,
Furthermore, two different partition plates 40 and 50 are shown.

Both of these partition plates 40 and 50 are connected to the window 40.
a, fold slightly below the upper edge of 50a,
This is the same as the first embodiment in that there is a gap l between the reference surfaces 40A, 50A of the partition plate and the upper edge of the window, but in addition, the upper edge is It is distinctive in that it has buffer ribs 40b and 50b that form acute angles with the reference plane. Such a partition plate 40,
50 is used when the distance between the base plate 1 and the cover plate 3 is narrowed. In this case, if the slit-forming blade 13 has a large deflection, the blade may collide with the upper edge of the window of the diaphragm, but the tip of the slit-forming blade 13 cannot be taken large. slides on the buffer ribs and heads upwards, so
Such collisions do not substantially adversely affect trailing blade travel and thus proper exposure.

As explained above, according to the present invention, it is possible to prevent the slit-forming blades in the rear blade group from colliding with the diaphragm during exposure, or even if they collide, the resulting damage to the rear blade group can be prevented. Since the present invention has the effect of minimizing adverse effects on driving, the present invention is extremely useful in achieving higher speed camera shutters.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the conventional focal plane shutter in a stationary state, Figure 2 is a perspective view of the partition plate in the conventional example shown in Figure 1, and Figure 3 is a cross-section of the conventional example shown in Figure 1 when winding is completed. Figure 4 is a sectional view of the first embodiment of the present invention in a resting state, and Figure 5 is
The figure is a perspective view of the partition plate in the previous embodiment, and FIG.
FIG. 7 is a perspective view of a partition plate according to a second embodiment of the present invention, FIG. 8 is a sectional view of the partition plate shown in FIG. 7, and FIG. 9 is a third embodiment of the present invention. FIG. 10 is a sectional view of the partition plate shown in FIG. 1...Main plate, 2...Partition plate, 3...Cover plate, 4,5
...Blade holding plate, 6-9... Leading blade group (6... Slit forming blade), 10-13... Trailing blade group (1
3...slit forming blade), 20... partition plate (20
a...window, 20b, 20c...slope), 40...
Partition plate (40a...window, 40b...buffer rib),
50... partition plate (50a... window, 50b... buffer rib).

Claims (1)

[Scope of Claims] 1. A leading blade group and a trailing blade group consisting of a plurality of arms whose main body is pivotally connected to a base plate by respective shafts, and a plurality of opaque plate blades which are pivotally connected to each of the arms. In a focal plane shutter that has a group of blades and a partition plate having a mapping window between the leading blade group and the rear blade group, the partition plate is moved in the same direction as the traveling direction of the rear blade group. It has an inclination in the direction approaching the rear blade group along the stack of the rear blade group, reaches its maximum near the front edge of the mapping window, and then tilts away from the rear blade group again. Focal plane ivy is characterized by: