JPH0453624Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is a focal plane shutter blade made of an opaque thin plate divided into a plurality of pieces, in particular, a slit-forming blade is moved to a predetermined stopping position after the shutter is operated. This invention relates to a focal plane shutter for a camera equipped with a blade holding plate for accurately guiding the camera.

[Prior art]

A tip consisting of a plurality of operating arms that are rotatably supported by respective shafts with the main body as a base plate, and a plurality of opaque thin plate-shaped shutter blades that are divided into a plurality of pieces and that are pivotally connected to each of the operating arms. A partition plate (intermediate plate) having a mapping window that serves as an optical path during photography is arranged between the blade group and the rear blade group, and further faces the main body of the operating arm with the mapping window in between. Conventionally, a focal plane shutter for a camera has a fixing part on the base plate, and a blade holding plate on the opposite side of the partition plate to sandwich a group of blades located therebetween. A blade holding plate is arranged at the tip of each blade, that is, the end opposite to the side supported by the operating arm, to hold the blade when the shutter is operating, that is, when the blade is traveling and when it is stopped.The shape of the blade holding plate is is shown in Figure 2b.

In such conventional focal plane shutters, when the shutter blades are about to end their travel, i.e., just before they stop, the main plate and blades are moved to prevent the slit-forming blades from interfering with or coming into contact with the mapping window of the main plate or partition plate. A method is used in which the above-described blade holding plate is provided between the partition plate and the blade holding plate, and the ends of the blade group are held between the partition plate and the blade holding plate to alleviate shaking and bouncing.

However, the shutter speed, which used to be around 1/1000 seconds, has recently been required to be faster, such as 1/2000 or 1/4000 seconds, and in order to improve strobe synchronization speed, It has become necessary to further increase the running speed of the shutter blade.

In response to these demands, the materials used to form shutter blades also required major changes to become thinner and lighter, and these results led to the selection of materials such as aluminum and plastic for the blades. Summer.

These market needs have had a major impact on the strength of the blades.

Due to the dramatic increase in the running speed of the shutter blades, in order to simultaneously brake and stop within a very short time and short distance, the impact causes bounce and waving phenomena of the shutter blades, which is incomparable to conventional methods. The results had a rather large impact.

As a result, a situation has once again occurred in which the slit-forming blades in the rear blade group come into contact with or collide with the mapping window of the partition plate or the main plate due to bouncing or waving phenomena.

In order to avoid this situation, it is common practice to increase the thickness of the plate again, but this goes against the original goal of reducing weight and causes a reversal phenomenon that becomes an obstacle to achieving higher speeds. There was an inconvenience that caused this.

[Purpose of invention]

The purpose of this invention is to reduce the weight of the shutter blade itself in view of the above-mentioned disadvantages, and to create a focal plane shutter for cameras that can achieve high speeds by reducing the waving phenomenon during braking and stopping. Our goal is to provide the following.

[Structure of the idea]

The purpose of the present invention described above is to arrange the blade holding plate between the partition plate and the main plate so that the blade group is sandwiched between the blade holding plate and the partition plate, thereby preventing the waving of the traveling blade group. In order to reduce this and particularly guide the slit-forming blades to the stopping position accurately, the shape of the blade holding plate described above is designed to guide the ends of the traveling blade group, and also to guide the blades near the middle part of the blades, or Furthermore, this is achieved by providing an extension part that guides the vicinity of the main body and at the same time providing an inclined part at the edge of the extension part on the mapping window side.

[Example of idea]

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of essential parts of an embodiment of the present invention, with the drive mechanism section omitted.

FIG. 2 is a plan view showing the blade holding plates of Example A of the present invention and Conventional Example B side by side.

1 is the base plate, and the mapping window 1 serves as the optical path during shooting.
It has a.

It is erected on the main plate 1 with a two-pin pin, and a stepped portion 2a is provided around its axis.

Reference numeral 3 denotes a rear blade holding plate, which has shafts 1b, 1c and a pin 2 erected on the opposite side of the base plate 1 from the side on which the main part of the operating arm (to be described later) is supported.
The mapping window 1a is supported especially from the fixed part to the mapping window 1a.
A recess 3b is formed at the tip of an extension 3a extending along the edge on the side where the rear blade travels to near the middle portion so as to fit into the stepped portion 2a of the pin 2. Furthermore, the edge 3c is inclined toward the operating arm from the base. As a result, the shafts 1b, 1c
It is possible to support the extension part 3a, which tends to become unstable when separated from the fixed part of the extension part 3a, and at the same time, it becomes possible to easily determine the reference position in the height direction from the base plate 1.

Reference numeral 4 denotes a rear blade group, which is composed of a plurality of opaque thin plates 4a to 4e, and the main part of each blade is supported by a plurality of operating arms 5 and 6 so as to be able to move in parallel. . Of the rear blade group 4, 4a in particular is a slit forming blade, which forms an exposure slit during photographing.

Reference numeral 7 denotes a partition plate (intermediate plate), which has a mapping window 7a which becomes a light path during photographing.
The lower edge 7b, which is one of the edges forming the rear blade and is the edge on the side from which the trailing blade travels, is formed with an inclination. The partition plate 7 is supported by the base plate 1 on each axis, and in order to determine the reference position in the height direction at the middle part, the apex of the female pin 2 set on the base plate 1 is used. There is.

Reference numeral 8 denotes a leading blade group, which is not shown, but is formed from an opaque thin plate divided into a plurality of pieces like the trailing blade group 4, and is pivoted so as to be movable in parallel by a plurality of operating arms (not shown). It is formed so that it runs over the mapping window during photographing.

Since the partition plate 7 is disposed between the leading blade group 8 and the rear blade group 4, the rear blade group 4 is arranged between the partition plate 7 and the main plate 1.
Since the leading blade group 8 is arranged facing each other with the partition plate 7 in the middle and runs in front of the gap between This prevents such interference from occurring.

Reference numeral 9 denotes a leading blade holding plate, which is caused to travel in the space existing between the leading blade group 8 and the partition plate 7, and accurately guides the leading blade group 8 into the traveling space.

Reference numeral 10 denotes a cover plate, which is fixed to the main plate 1 by a well-known method (in this embodiment, by using a plurality of shafts and screws), and the above-mentioned members are arranged in the space existing between it and the main plate 1. .

Since this embodiment has the above-described configuration, when the shutter is operated, the slit forming blades 4a of the rear blade group 4 are first
The vehicle travels while being guided by the slope of the edge 7b so as not to deviate from a predetermined travel space.

At the same time, the middle part of the rear blade group 4, in particular the slit-forming blade 4a, whose main part is supported by the actuating arms 5 and 6 and whose other end is guided by the rear blade holding plate 3, changes from high-speed running to a rapid stop. The waving phenomenon that occurs is suppressed by slanting the edge 3c of the extension 3a newly provided on the rear blade holding plate 3 in the same way as the lower edge 7b of the partition plate 7.

In this way, the rear blade group 4, particularly the slit-forming blade 4a, can be accurately guided by the inclined portions provided on the rear blade holding plate 3, the extension portion 3a, and the partition plate 7.

Furthermore, although this embodiment describes a group of divided blades, good results can also be obtained with a single blade that is not divided, and the number of actuating arms is limited to two. Of course not.

Furthermore, it is not necessary that all the blades constituting the blade group be supported by a plurality of operating arms, and the blades other than the slit forming blade may be moved by, for example, cam grooves and screws.

[Effect of idea]

As mentioned above, by implementing the present invention, it is possible to ensure accurate running space for shutter blades that are becoming lighter and thinner in order to meet the recent market needs for faster shutter speeds. It is possible to provide a focal plane shutter, which is the object of the present invention, and which allows for guiding without increasing the number of parts. In addition, to support the extended part of the blade holding plate, which tends to become unstable due to extension, a pin that supports the partition plate in the middle and regulates the height is commonly used, and it is supported by a stepped part provided on the pin. In addition, the present invention provides a focal plane shutter that achieves the initial purpose of the present invention, which is that it can be used as a reference position determining member that regulates the distance from the main plate as well as the distance from the partition plate, and which also provides further effects. can.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the main parts showing an embodiment of the present invention, Fig. 2a is a plan view of a blade holding plate showing an embodiment of the invention, and Fig. 2b is a conventional example. It is a top view of the shown blade|wing holding board. 1...Main plate, 2...Memory pin, 2a...Stepped portion,
3... Rear blade holding plate, 3a... Extension part, 3b...
... recess, 3c... edge (slanted part), 4... trailing blade group,
4a... Slit forming blade, 5, 6... Operating arm, 7... Partition plate, 7b... Lower edge, 8... Leading blade group, 9... Leading blade pressing plate, 10... Covering plate.

Claims (1)

[Claims for Utility Model Registration] A plurality of arms whose main body is pivotally connected to a base plate by respective shafts, and at least the slit-forming blades are a plurality of opaque thin plate-like blades which are pivotally connected to each of the arms. a partition plate having a leading blade group and a trailing blade group, and having a mapping window between the leading blade group and the trailing blade group; A focal plane shutter comprising a rear blade holding plate having a fixing portion on a base plate, and a rear blade holding plate arranged to sandwich a group of rear blades located between the main plate and the partition plate on the opposite side of the main plate, the rear blade holding plate has an extension part that is close to the edge of the main plate on the side from which the rear blade of the window runs and extends to about the middle of the window in the width direction, and the edge of the extension part extends from the base of the extension part. Focal plane ivy is characterized by its slope in the direction away from the window.