JPS6226011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a focal plane shutter for a camera comprising a leading blade group and a trailing blade group each consisting of a plurality of divided opaque blades.

[Prior art]

Conventionally, a plurality of arms and a plurality of opaque thin plates constitute one set of shutter blades, the thin plates are pivotally attached to the arms, and a partition plate is provided between the two sets of shutter blades. Such a focal plane shutter has many advantages, such as a simple structure and stable operation. In order to reduce the force required, 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 made thinner, the rigidity of the blade decreases and the slit formation during exposure operation becomes difficult. Due to the distortion caused in the blade, the slit-forming blade could violently collide with the upper edge of the mapping window of the diaphragm, which could not be prevented by making the mapping edge sloped.

[Purpose of the invention]

The present invention solves the disadvantages of the conventional focal plane shutter described above, and solves the problem of mapping the slit-forming blades in the so-called rear blade group and the partition plate among the two sets of shutter blades. The object of the present invention is to provide a mechanism that prevents collision with the edge surface of a window or weakens the collision.

[Structure of the invention]

An object of the present invention is to provide an end surface of an edge located on the forward side where the trailing blade group moves during exposure, among the edge surfaces of a partition plate disposed between the leading blade group and the trailing blade group. In the direction away from the trailing blade group,
This is achieved by having a buffer rib formed at an acute angle in the direction opposite to the travel of the trailing blade group.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a focal plane shutter for a camcorder according to a first embodiment of the present invention, showing a stationary state (a state after exposure is completed).
In order to make the drawings easier to read, some parts are omitted and the enlargement ratios of the vertical and horizontal dimensions are changed.

FIG. 2 is a perspective view of a diaphragm showing the first embodiment, and FIG. 3 is a sectional view of the diaphragm.

1 is a shutter base plate, which has a window 1a for mapping.

Reference numeral 2 denotes a partition plate which, like the shutter base plate 1, has a mapping window 2a, and whose role is to prevent collisions between the leading blade and the trailing blade.

The window 2a of the partition plate 2 is bent toward the leading blade group at a portion slightly below its upper edge to prevent blade collision, and there is a gap between the reference surface 2A of the partition plate and the upper edge of the window 2a. has a distance of "1".

In addition, the reason why the reference plane 2A is angled so as to be oblique to the base plate 1 is to prevent collisions and to
At the same time, by keeping the distance between both slit forming blades 6 and 13 of the leading blade and trailing blade described later constant, light leakage can be prevented and the uniformity of the exposure amount can be maintained.

Further, the upper edge of the mapping window 2a forms an acute angle "θ" with the reference plane, and has a buffer rib 2b.

Placing the partition plate between the leading blade group and the trailing blade group in this way allows the main plate 1 to be used while avoiding accidents where the leading blade group and the trailing blade group that are close to each other contact or buffer each other. This is to narrow the distance from the cover plate 3, and the reason why it has this angle is to further narrow the distance.

If the distance between the base plate 1 and the cover plate 3 is narrowed, the above-mentioned distance 1 cannot be made large, and if the slit-forming blades 13 are distorted greatly when they travel, in rare cases the blades 13 may However, since the tip of the slit-forming blade 13 slides on the buffer rib 2b and runs while escaping upward, such a collision may cause the leading blade to collide with the upper edge of the window 2a. There is no adverse effect on the running of the camera and, by extension, on proper exposure.

3 is a cover plate, and 4 and 5 are blade holding plates.

6, 7, 8, and 9 are each made of an opaque thin plate, and have a base portion pivotally connected to two opening actuating arms (not shown) that are pivotally connected to the base plate 1 by respective shafts, and have free ends. The leading blade group is configured to run in the vertical direction in FIG. 1 in the space existing between the blade holding plate 4 and the partition plate 2.

The pivot point between each of the leading blades and each of the opening actuation arms, and the pivot point of the opening actuation arm to the main plate are as follows:
They are mutually positioned so as to form the four vertices of a parallelogram formed by connecting them, and each leading blade extends the slit-forming blade 6 forming one side of the slit to the most distal end of the operating arm. The other leading blades 7 to 9 are stacked one after another on the slit-forming blade, and the shafts pivoted in the order in which they are stacked are attached to the opening actuating arm so as to be closest to the opening actuating arm. It is arranged close to the main part of the 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.

Reference numerals 10, 11, 12, and 13 are rear blade groups each made of an opaque thin plate and run in the gap 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 respect to the leading blade group, and is therefore driven in the same manner.

In addition, in the rear blade group, the slit forming blade 13
forms the rear edge of the exposure slit.

In addition, although the number of blades is different in the mounting structure of the above-mentioned arm and each blade,
It is well known from Publication No. 19175 or Publication No. 54-19259.

The operation will be briefly explained below.

When a charge mechanism (not shown) performs shutter charge at the same time as the winding operation, first,
The leading blade group advances downward from the position shown in FIG. 1 with the slit-forming blade 6 at the top, one after the other, as if opening a fan, while remaining in an overlapping state.

The leading blade groups 6 to 9 cover the mapping window 2a, and when the shutter release operation is performed, the leading blade groups 6 to 9 are arranged in a fan position with the blade 9 at the front and the slit forming blade 6 at the rear. As if closing, it converges and moves upward.

When the leading blade groups 6 to 9 run, the trailing blade groups 10 to 13 follow with a predetermined time difference given by a control mechanism/circuit (not shown) with the slit forming blade 13 in the lead while deploying their blades. It moves and travels in this manner to perform exposure, and returns to the state shown in FIG. 1 again.

[Other Examples]

FIGS. 4 and 5 are a perspective view and a sectional view, respectively, of a diaphragm, showing a second embodiment of the present invention.

In this embodiment, unlike the first embodiment, no bending portions or the like are provided on the side edges of the mapping window 2a, and a buffer rib 2b is provided only on the upper edge of the mapping window 2a. has been established.

By having only one bent portion, there is virtually no effect on the original purpose and effect of the present invention, which is to buffer the blade groups and to prevent the slit-forming blades of the rear blade group from colliding with the edge of the mapping window. This embodiment has the advantage that manufacturing of the partition plate 2 is relatively easier than that of the first embodiment, without causing any adverse effects.

Further, in both the first and second embodiments of the present invention, the diaphragm extends from the side where the trailing blade groups converge toward the edge of the trailing end along the stack of the trailing blade groups. It has an inclination in the direction approaching the rear blade group, and then, near the front edge, it is bent again in the direction away from the trailing blade group, forming a roughly “he” shape, but the buffer rib is It may be formed as a flat plate as long as it has only a minor effect on running.

In addition, in both the first and second embodiments described above, the running direction of each blade at the time of exposure is
In the drawings, the direction of travel is from the bottom to the top, but it goes without saying that the direction of travel is not limited to this. It is necessary to change the slope of the board.

〔Effect of the invention〕

As is clear from the above, by carrying out the present invention in which the upper edge of the mapping window of the partition plate is provided with a rib formed by a bent portion,
While reducing the left and right dimensions of the shutter (as seen in the drawing), the original role of the partition plate, which is to prevent the leading and trailing blades from interfering with each other during running, is reduced, and in particular, the rear blade group It is possible to provide a focal plane shutter that prevents the slit-forming blades therein from colliding with the upper edge of the mapping window received in the partition plate just before completing their travel.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a focal plane shutter showing a first embodiment of the present invention, and FIG. 2 is a perspective view showing a partition plate, which is also a first embodiment of the present invention. , FIG. 3 is a sectional view of the partition plate according to the first embodiment of the present invention, FIG. 4 is a perspective view showing the partition plate according to the second embodiment of the invention, and FIG. FIG. 2 is a sectional view of a partition plate according to a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Shutter base plate, 2... Partition plate, 2a... Mapping window, 2b... Buffer rib, 2A... Reference surface, 3... Cover plate, 4, 5... Blade holding plate, 6-9... Lead blade group,
6... Slit forming blade, 10-13... Rear blade group,
13...Slit forming blade.

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 comprising a group of blades and a diaphragm having a mapping window between the leading blade group and the trailing blade group, In this case, the end face of the edge located on the forward side where the trailing blade group moves during exposure has an acute angle in the direction away from the trailing blade group and in the direction opposite to the traveling direction of the trailing blade group. A focal plane ivy characterized by having ribs formed by