JPH0453622Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention uses a focal plane shutter blade group consisting of a plurality of opaque thin plates to prevent cracks when the shutter stops after running for photographic exposure. Related to focal plane ivy that protects from damage such as.

[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 fixed 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. It is widely used to adopt a configuration in which a blade holding plate is placed at the tip of each blade, that is, the end opposite to the side supported by the operating arm, to hold the blade in place when the shutter is operating, that is, when the blade is traveling and when it is stopped. It is being

In such conventional focal plane shutters, when the shutter operation ends, that is, just before it stops, among the plurality of divided blades, especially the second blade that overlaps with the slit forming blade,
Damage such as cracks often occurs due to interference such as contact and collision due to waving and deflection of the area near the pivot point to the actuating arm and the corner of the mapping window provided in the bulkhead. Summer.

This trend has shown signs of increasing in recent years, and the reasons for this are thought to be as follows.

The shutter speed, which was conventionally around 1/1000 seconds, has also been reduced.
Recently, higher speeds such as 1/2000 and 1/4000 seconds have been required, and in order to improve strobe synchronization speed, it has become necessary to further increase the running speed of the shutter blade. Ta.

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

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]

In view of the above-mentioned disadvantages, the purpose of this invention is to
Braking and
An object of the present invention is to provide a focal plane shutter for a camera that prevents cracks and damage in the vicinity of a pivot point to an operating arm caused by waving and deflection of shutter blades when stopped.

[Structure of the idea]

The purpose of the present invention described above is to change the shape of the corner of the mapping window provided in the partition plate located between the leading blade group and the trailing blade group near the actuating arm on the side where the blade is stopped so that it does not interfere with the blade. This is achieved by providing an arcuate relief part that avoids this.

[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 2-fitting 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 on each axis by the base plate 1, 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. Also, among the corners forming the mapping window 7a, the shutter operation stop side (lower edge) of the forming slit blade 4a of the rear blade group 4
The corner 7c on the side of the actuating arms 5 and 6 is formed into an arcuate shape with a larger curvature than the other corners.

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, each blade group does not come into contact with or collide with each other when the shutter is operated or when the shutter is charged. This prevents unwanted interference from occurring.

Reference numeral 9 denotes a leading blade holding plate, which allows the leading blade group 8 to travel in the space existing between it 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 adopts the above-described configuration, when the shutter is operated, the rear blade group 4 runs downward from the rear blade overlapping portion located at the upper side in the drawing, with the slit forming blade 4a at the beginning.

The rear blade group 4 runs over the imaging window (photographing opening) and covers the entire surface, and immediately before the shutter operation ends, rapid braking and stopping are performed, and at this time, the second blade 4b Due to inertia and impact when stopped,
This will cause temporary deformations such as waving and bouncing.

This deformation of the second blade 4b is applied to the corner 7 of the partition plate 7.
The large arc drawn at c lets it escape.

This makes it possible to avoid a collision between the pivot portion of the second blade 4b and the edge of the partition plate 7 due to deformation caused by the conventional second blade 4b.

[Effects of the invention] As mentioned above, by implementing the invention, the shutter blades, which are becoming lighter and thinner, can be used to meet the recent market demand for higher shutter speeds. It can avoid shocks caused by rapid braking and interference when stopping.
A focal plane shutter that protects the shutter blade from damage such as cracks can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of essential parts showing an embodiment of the present invention, Fig. 2a is a plan view of a partition plate showing an embodiment of the invention, and Fig. 2b shows a conventional example. FIG. 1...Main plate, 2...Memory pin, 2a...Stepped part,
3... Rear blade holding plate, 3a... Extension part, 3b...
... Convex portion, 4... Rear blade group, 4a... Slit forming blade, 4b... Second blade, 5, 6... Operating arm, 7... Partition plate, 7b... Lower edge, 7c... Corner Department,
8... Lead blade group, 9... Lead blade holding plate, 10...
...Cover board.

Claims (1)

[Claim for Utility Model Registration] A leading blade group and a trailing blade consisting of a plurality of arms whose main body is pivotally connected to the base plate by respective shafts, and a plurality of opaque plate blades which are pivotally connected to each of the arms. A partition plate having a group of blades and a mapping window between the leading blade group and the trailing blade group, and a cover plate on the side opposite to the main plate of the partition plate so as to sandwich the blade group located therebetween. In the focal plane shutter formed by the arrangement, among the corners of the mapping window of the bulkhead, at least on the side where the rear blade group travels, there is a circle in the corner near the attachment point of each blade to the arm. Focal plane ivy is characterized by its arc-shaped ridges.