JP3705854B2 - Focal plane shutter for camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a focal plane shutter for a camera.
[0002]
[Prior art]
The blade group has two blade groups, a front blade group and a rear blade group, each blade group rotatably connecting a plurality of blades to a plurality of arms, and a deployment position that covers the aperture and a superimposed position that opens the aperture There is known a focal plane shutter for a camera that is allowed to travel between the two. In such a blade group, the arm and the blade are rotatably connected by a connecting shaft. Usually, the connecting method is such that the tip of the connecting shaft is inserted into a hole formed in the arm and the blade from the arm side. The tip is caulked to the blade. As a result, the arm is rotatable between the head of the connecting shaft and the blade with respect to the connecting shaft integrated with the blade. On the other hand, these blade groups are arranged between a plurality of plates having aperture-forming opening end faces, and at least the connecting shafts connecting the slit forming blades among the connecting shafts are in the deployed position of the blade groups. It exists in the aperture. Then, when traveling to the overlapping position, it passes through the above-described aperture forming end surface position.
[0003]
By the way, since the blades of this type of focal plane shutter are extremely thin, there is a risk of light leakage from the space between the blades or between the blades and the above plate at the deployed position covering the aperture. Therefore, the plate having the opening end face for aperture formation described above is designed so that the gap between them is as narrow as possible. In addition, a special blade retainer plate may be provided at the sliding portion of the blade tip. ing. However, the blade group not only moves in the traveling direction during traveling, but also performs various complicated movements. The slit forming blades are connected at the tip of the arm and are located closest to the aperture forming opening end surface than the other blades, and are pushed up because the blades overlap each other, especially when the blade group travels to the overlapping position. . Moreover, since the blade has the largest operating amount, it is most susceptible to the above-described movement. Therefore, when the connecting shaft moves in the axial direction, that is, in a direction (optical axis direction) orthogonal to the aperture surface, the head may collide with the aperture forming opening end surface.
[0004]
In order to prevent such a collision, conventionally, a thin portion is formed along the traveling locus of the connecting shaft on the plate having the aperture forming opening end face described above so as to avoid the collision. Furthermore, a slope is formed at the opening edge of the aperture for aperture formation, and when the head of the connecting shaft comes into contact with the slope, it is guided along the slope so that it is corrected to the normal running posture. It was made.
[0005]
[Problems to be solved by the invention]
However, the method for forming the thin portion as described above is possible if the plate to be formed is a relatively thick plate such as a shutter base plate, but it is disposed at a position closer to the film surface than the shutter base plate. In the case of a relatively thin plate such as a cover plate, it is practically impossible to adopt such a method. For this reason, conventionally, such a thin plate has been provided with the above-described cut groove or slope portion by bending the opening edge portion. However, when the cut groove is provided, it is also a position where the blades are overlapped, and the cut groove is considerably large, which is a very disadvantageous configuration for preventing light leakage. In recent years, there are many cameras that can select a panoramic screen. However, such a camera has a member that restricts the panoramic image frame disposed between the cover plate and the film surface. If the above-mentioned slope is provided, there is a risk of interference with the panoramic image frame restricting member, and there is a problem that it is extremely difficult to arrange the blade group close to the film surface.
[0006]
Further, as described above, another method for preventing the phenomenon that the caulking dowel (the connecting shaft for caulking the blade and connecting with the arm) collides with the opening edge of the cover plate during the travel of the blade group in the exposure operation or the setting operation. In order to keep the connecting shaft of the blade traveling to the opening edge away from the cover plate, it may be possible to provide the cover plate with a projection that contacts the arm surface, but such a projection is provided at a fixed position. For this reason, the blade must be provided at a position that avoids contact with a plurality of connecting shafts during traveling of the blades, which has the disadvantage that the selection width of the arrangement position is extremely small.
[0007]
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to connect a plurality of blades to a plurality of arms by a connecting shaft so as to be rotatable. Provided is a focal plane shutter for a camera capable of preventing a collision between the connecting shaft and the opening end surface during traveling of a blade group without performing special processing on a shutter base plate and a cover plate that are configured. That is.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a plurality of blades are pivotally attached to the base plate and project from the arms into a plurality of arms extending from the pivotally attached portion into the aperture forming opening. has a rotatably coupled blades are in connection shaft having a head portion which, between the superimposed position the vane group opens the deployed position and the aperture forming opening to cover said aperture forming opening In the focal plane shutter for a camera configured to travel, at least one of the coupling shafts is disposed on the arm in a portion that moves in the aperture forming opening, and only the outside of the aperture forming opening moves. A protruding portion that protrudes beyond the maximum protruding height of the head of the connecting shaft is formed in the portion to be connected.
Further, the invention according to claim 2 has a plurality of blades pivotally attached to the main plate, and a plurality of arms extending from the pivotally attached portion into the aperture forming opening, each having a head protruding from the arm. has a blade group which is rotatably connected by a connecting shaft, the vane group was made to travel between the superimposed position to open the deployed position and the aperture forming opening to cover said aperture forming opening camera In the focal plane shutter, the arm is located in the aperture forming opening at the unfolded position, and when traveling to the overlapping position, the aperture precedes the connecting shaft that reaches the end surface of the aperture forming opening first. only the portion that reaches the forming the opening end face, gentle induced in contact with the aperture forming the opening end face with which protrudes than the maximum protrusion height of the head of the connecting shaft It is characterized in that the formation of the convex portion having a.
The invention described in claim 3 is characterized in that the convex portion is formed by processing the arm itself.
According to a fourth aspect of the present invention, the convex portion is formed by newly planting the surface of the arm.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a principle diagram of the present invention, wherein (a) is a principle diagram viewed from the side with a part broken away, and (b) is a principle diagram viewed from the front.
As apparent from FIGS. 1A and 1B, the embodiment according to the present invention has the connecting shaft heads 12a and 13a on the end face of the aperture forming opening 2a when the blade group travels to the overlapping position. The basic principle is that convex portions 5a and 6a projecting from the maximum projecting height of the connecting shaft head are provided at appropriate positions on the surfaces of the arms 5 and 6 so as not to collide.
Embodiments of the present invention will be described below with reference to a first example shown in FIGS. 2, 3 and 4 and a second example shown in FIGS.
[0010]
First embodiment Fig. 2 shows a state in which the leading blade group is in a deployed position, i.e., a set position, covering the aperture, and Fig. 3 shows a state in which the leading blade group is being exposed. 4 shows a cross-sectional view of the main part in FIG. FIG. 2 is a view as seen from the photographer side of the camera, that is, the film surface side. Although the outer shape is omitted, as shown in FIG. 4, the shutter base plate 1 is disposed on the photographing lens side and the film surface side is disposed. A cover plate 2 is arranged. Usually, a plate called an intermediate plate is arranged between these plates 1 and 2, and a rear blade group is provided between the shutter base plate 1 and the intermediate plate, and the intermediate plate and the cover plate 2 are connected. A leading blade group is disposed between them, but the intermediate plate and the trailing blade group are omitted in FIGS. 2 to 4. The shutter base plate 1 and the cover plate 2 are provided with aperture forming openings 1a and 2a each having a rectangular shape. These openings, including openings provided in an intermediate plate (not shown), do not actually form a correct rectangle, and a rectangular aperture is formed by combining these openings.
Accordingly, as can be seen from FIG. 2, the aperture forming opening is the opening 1a formed in the shutter base plate 1 as viewed in this figure. However, in the description of the present invention, all of these openings are apertures. The openings will be referred to as forming openings, and the end faces thereof will be referred to as aperture forming opening end faces.
[0011]
The pivoting shafts 3 and 4 are planted on the shutter base plate, and the pivoting shaft 4 is usually an attachment shaft for the cover plate 2. Arms 5 and 6 are pivotally attached to the shafts 3 and 4. The arm 6 is formed with a hole 6b into which a pin planted on a drive lever (not shown) is fitted. The leading blade group includes five slit forming blades 7 and covering blades 8, 9, 10, and 11, and the slit forming blades 7 are rotatably connected to the tip portions of the arms 5 and 6 by connecting shafts 12 and 13. Has been. In this connection method, rivet-shaped connection shafts 12 and 13 having heads are passed through holes provided in the arms 5 and 6 and the blade 7, and the tips thereof are integrated with the blade 7 by caulking. Similarly, the blade 8 is connected with the connecting shafts 14 and 15, the blade 9 is connected with the connecting shafts 16 and 17, the blade 10 is connected with the connecting shafts 18 and 19, and the blade 11 is connected with the connecting shafts 20 and 21, respectively. Has been. And the convex part 5a, 6a formed in these arms 5 and 6 is formed long so that the length which protrudes in the direction of the cover board 2 can be seen in FIG. 4 compared with a connection shaft.
In FIG. 4, the arm is processed to form the convex portion, but the same is true even if the shaft is planted at a similar position.
[0012]
2, the heads of the connecting shafts 13 and 15 are inside the aperture forming opening 2a of the cover plate 2, and the other connecting shafts are located outside the opening. When the release is performed in this state, the arm 6 is rotated counterclockwise by a drive lever (not shown). Since the arms 5 and 6 and the blades 7 to 11 constitute a parallel link mechanism, the arm 5 is also rotated counterclockwise, and the blades 7 to 11 are moved downward and folded. At this time, the convex portions 5a and 6a formed on the arm are provided at positions that move outside the opening.
[0013]
Ideally, the traveling of the blade group performed in this way should be performed in a plane parallel to the drawing, but in reality, a force in a direction (optical axis direction) perpendicular to the traveling direction for various reasons. Since the blades and the arms are made of a thin flexible material, it is known that the blades and the arms are greatly bent particularly in the aperture forming opening. The connecting shafts 12 and 13 provided on the distal ends of the arms 5 and 6 are caulked by the blades 7. Since the blades 7 are positioned closest to the arms 5 and 6, when the blade group travels to the overlapping position, the blades overlap each other, so that the connecting shafts 12 and 13 are particularly pushed up to the cover plate 2. appear.
[0014]
Therefore, when the connecting shafts 12 and 13 pass from the inside of the aperture forming opening to the outside of the aperture forming opening in the traveling process of the middle plate as shown in FIG. 3, the head collides with the opening end surface of the cover plate 2. However, in this embodiment, as shown in FIG. 4, since the convex portions 5a and 6a formed on the arms 5 and 6 protrude further than the connecting shaft head, the cover plate As described above, the bending and push-up as described above are suppressed by the contact with 2 and do not collide with the opening end face.
In the present embodiment, the case where the present invention is applied to the leading blade group has been described, but the same can be said for the trailing blade group. In particular, it is normally located at the unfolded position that covers the aperture together with the leading blade group, and is effective when used for the trailing blade group that returns to the overlapping position, that is, the exposure running start position at the initial stage of the camera release.
[0015]
Second embodiment Next, a second embodiment of the present invention will be described.
In the first embodiment described above, the protrusions 5a and 6a formed on the arm are always provided at a position that moves outside the aperture forming opening. However, this example is not used at the set position shown in FIG. 6 and 7, as shown in FIGS. 6 and 7, the heads of the connecting shafts 12 and 13 enter the outside of the opening just before the aperture forming opening end surface 2a, and the heads of the connecting shafts 12 and 13 are connected to the opening end surface 2a. Prevent collisions. The convex portions formed on the arm are the same even if the shaft is planted on the arm in the same manner as in the first embodiment. In this embodiment, when the blade group is in the traveling state, it can be operated without forcibly restricting the blade, and since the convex portion formed on the arm acts immediately before the end of the traveling operation, it can be used more effectively.
[0016]
In each of the above embodiments, the relationship between the head of the connecting shaft and the aperture forming opening end surface of the cover plate has been described, but the same applies to the relationship between the shutter base plate and the connecting shaft.
The shape of the protrusion is preferably a gentle shape in consideration of the phenomenon of contact with the opening edge, for example, a convex portion based on a spherical shape.
Thereby, in the contact with the opening edge, it is guided to the gentle shape and the collision phenomenon does not occur.
[0017]
【The invention's effect】
According to the present invention, the shutter base plate having the aperture forming opening, the connecting shaft connecting the blade and the arm during the traveling of the blade group, and the aperture forming opening end surface without providing the cut groove and the inclined surface on the cover plate. Can be prevented.
[Brief description of the drawings]
FIG. 1A is a sectional view showing the principle of the present invention, and FIG. 1B is a front view showing the principle of the present invention.
FIG. 2 is a front view showing a state in which the leading blade group of the first embodiment according to the present invention covers the aperture.
FIG. 3 is a front view showing a state in the middle of traveling of the leading blade group of the first embodiment according to the present invention.
FIG. 4 is a cross-sectional view of a main part of a first embodiment according to the present invention.
FIG. 5 is a front view showing a state in which the leading blade group of the second embodiment according to the present invention covers the aperture.
FIG. 6 is a front view showing a state in which the leading blade group of the second embodiment according to the present invention is in the middle of traveling.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a Aperture formation opening 2 Cover plate 3, 4 Pivoting shaft 5, 6 Arm 5a, 6a Convex part 6b Hole 7 Slit formation blades 8, 9, 10, 11 Cover blades 12, 13, 14, 15 , 16, 17, 18, 19, 20, 21 Connecting shaft 12a, 13a Connecting shaft head

Claims (4)

A plurality of blades pivotally connected to a base plate and rotatably connected to a plurality of arms extending from the pivoted portion into the aperture forming opening by a connecting shaft having a head protruding from the arm. has a group, in the camera focal plane shutter which is adapted to travel between a superimposed position to open the deployed position and the aperture forming opening to the vane group covers the aperture forming opening,
In the arm, at least one of the connecting shafts is disposed in a portion that moves within the aperture forming opening, and a portion of the arm that moves only outside the aperture forming opening has a maximum of the head of the connecting shaft. A focal plane shutter for a camera, wherein a convex portion that protrudes beyond a protruding height is formed. A plurality of blades pivotally connected to a base plate and rotatably connected to a plurality of arms extending from the pivoted portion into the aperture forming opening by a connecting shaft having a head protruding from the arm. has a group, in the camera focal plane shutter which is adapted to travel between a superimposed position to open the deployed position and the aperture forming opening to the vane group covers the aperture forming opening,
The arm is in the aperture forming opening at the unfolded position, and reaches the aperture forming opening end face ahead of the connecting shaft that reaches the aperture forming opening end face first when traveling to the overlapping position. A convex portion having a gentle surface that protrudes from the maximum protruding height of the head portion of the connecting shaft and has a smooth surface that is guided in contact with the aperture forming opening end surface is formed only on the portion. Focal plane shutter for camera.   3. The focal plane shutter for a camera according to claim 1, wherein the convex portion is formed by processing the arm itself.   The focal plane shutter for a camera according to claim 1, wherein the convex portion is formed by newly planting on the surface of the arm.

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