JP3373925B2 - Focal plane shutter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera provided with two sets of blade groups composed of a plurality of sheets.

[0002]

2. Description of the Related Art This type of focal plane shutter is
The leading blade group and the trailing blade group are each composed of a slit-forming blade and a cover blade, and each blade group is formed like a fan by the rotation of two arms pivotally attached to the sides of the exposure opening. It can be unfolded and folded. In addition, each blade group is arranged between two substrates having a substantially rectangular opening edge forming an exposure opening and an intermediate plate such that their traveling paths are isolated from each other, During the exposure travel, the front blade group is superposed on the outside of the exposure opening while deepening the overlap between the blades from the position where the exposure opening is closed, while the rear blade group travels in the same direction as the front blade group. Then, the overlapping shape is gradually expanded to close the exposure opening.

In such exposure running, the slit forming blade having the largest momentum in the trailing blade group collides with the edge formed in the running direction among the opening edges provided in the intermediate plate. May be damaged or scratched. In order to prevent this, various types of intermediate plates having a special shape have been proposed, and JP-A-58-22433 has been proposed.
Four examples are shown in Japanese Patent Publication No. In three of them, the slit-forming blades are bent substantially along the edge portions where collision occurs, and the entire intermediate plate is bent in the traveling path direction of the leading blade group, and two of them are further described above. Only the edge portion is bent toward the traveling path of the leading blade group. And the remaining one embodiment, without bending the intermediate plate,
A part of the trailing blade running path side is cut away by etching or milling from the edge of the slit forming blade toward the outside of the exposure opening to form a step.

[0004]

However, all of the above-mentioned four examples have the advantage of being able to prevent the collision between the slit-forming blades of the rear blade group and the intermediate plate, but have various other problems. have. That is, in the case where the entire intermediate plate is bent, if the intermediate plate is arranged so that the rear blade group travels obliquely toward the substrate, the edge of the slit forming blade will collide with the substrate, and the vertical position When the blades are arranged so as to travel, part of the intermediate plate faces the traveling path of the leading blade group, and therefore the edge of the blade closest to the intermediate plate in the leading blade group hits it. Also, in the case where the end edge of the intermediate plate is bent as described above, the blade on the side of the intermediate plate that is closest to the intermediate plate in the above-mentioned leading blade group collides with the bent portion during setting, and during setting and exposure traveling. In any of the above cases, the surface always rubs against the bent portion, and thus it is damaged. Further, those in which a part of the intermediate plate is etched or milled are not suitable for mass production because of high processing cost.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent slitting of the rear blade group without damaging the cover blade of the front blade group during exposure traveling. forming blade is to provide a full O over Culp Ren shutter configured as to avoid colliding with the opening edge of the intermediate plate.

[0006]

To achieve SUMMARY OF and act] of the object, off O over Culp lens shutter of the present invention,
A first substrate, an intermediate plate, and a second substrate, each of which is provided with a substantially rectangular opening edge for forming an exposure opening and is sequentially arranged so that the opening edges overlap, a slit forming blade and a cover blade. A front blade group having a second substrate and an intermediate plate, and a rear blade group having a slit forming blade and a cover blade and being disposed between the first substrate and the intermediate plate. Of the opening edges provided on the intermediate plate, at least a part of the opening edges formed in the traveling direction of each blade group is an inclined portion protruding toward the second substrate side, and viewed from the exposure opening. The thin plate is arranged so as to be in sliding contact with the blade closest to the intermediate plate in the front blade group outside the inclined portion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing a set state of the shutter,
FIG. 2 is a right side view of FIG. FIG. 3 is a diagram of main components excluding the blade group in the embodiment shown in FIG. Figure 4
[Fig. 6] is a partially enlarged view of the front blade group when opened and operating, as viewed from the right side. FIG. 5 is a front view showing the exposure end state, and FIG. 6 is a right side view of FIG.

First, the configuration will be described. The substrate 1 has a substantially rectangular opening edge 1a that forms an exposure opening and arcuate holes 1b and 1c. In FIG. 1, shafts 1d, 1e, 1f,
1g, 1h, 1i, 1j, 1k are planted. Below the substrate 1, a protrusion 1 is formed by an extrusion process.
In FIG. 1, m protrudes in the back direction, and a protrusion 1n having a tire-shaped head portion is also attached in the back direction by caulking. The leading blade arms 2 and 3 are pivotally attached to shafts 1j and 1k, and slit forming blades 4a
The front blade group 4 including the cover blades 4b, 4c, 4d, and 4e is pivotally supported in a known manner. Rear blade arm 5,
Reference numeral 6 is pivotally attached to shafts 1h and 1i, respectively, and pivotally supports a rear blade group 7 including slit forming blades 7a and cover blades 7b, 7c, 7d and 7e.

On the shafts 1f and 1g of the substrate 1, the rear blade pressing plate 8, the intermediate plate 9, the front blade pressing plate 10,
An auxiliary board 11 is attached, of which the trailing blade pressing plate 8, the intermediate plate 9, and the leading blade pressing plate 10 are mounted so as to be movable in the axial directions of the shafts 1f and 1g. The protrusion 1m is in contact with the intermediate plate 9, and the protrusion 1n is in contact with the rear blade pressing plate 8. The intermediate plate 9 has an opening edge 9a having a substantially rectangular shape that forms an exposure opening, and an inclined portion 9b having a shape bent toward the auxiliary substrate 11 is formed at an edge of each blade group 4, 7 in the exposure traveling direction. Are formed. The intermediate plate 9 is also attached to the shaft 1e so as to be movable in the axial direction. A thin plate 12 is attached to the shaft 1e and the shaft 1g so as to be movable in the axial direction. A spacer 13 is loosely fitted to the shaft 1g between the thin plate 12 and the leading blade pressing plate 10, and a spacer 14 is loosely fitted to the shaft 1f between the trailing blade pressing plate 8 and the intermediate plate 9. is doing.

The auxiliary substrate 11 has a substantially rectangular opening edge 11a for forming an exposure opening together with the opening edges 1a and 9a.
And a hole 11 in which a large diameter portion and a small diameter portion are continuously provided.
b, 11c, forked portions 11d, 11e, concave portions 11f, 11
g, and holes 11h and 11i. This auxiliary substrate 11
In order to integrally attach the substrate to the substrate 1, first, the holes 11b,
The large diameter portion 11c is loosely fitted into the shafts 1f and 1g, and is slid to the left in FIG. Thereby, although not explicitly shown, the shafts 1f and 1g are securely fitted into the small-diameter portions, and the forked portions 11d and 11e and the recesses 11f and 11g are provided.
Engage shafts 1h, 1k and shafts 1i, 1j , respectively. At this time, since the holes 11h and 11i correspond to the positions of the shafts 1d and 1e, they are fixed to the shafts 1d and 1e by screws (not shown).

Next, the operation will be described. FIG. 1 shows a state in which the shutter is set to the charge position. When the shutter is released in this state, the pin of the leading blade drive member (not shown) fitted in the hole 3a of the drive arm 3 operates along the arcuate hole 1c. This causes the drive arm 3 to rotate right about the axis 1k. Along with this, the arm 2 connected via the front blade group 4 also turns to the right. By the clockwise rotation of the leading blade arms 2 and 3, the leading blade group 4 moves downward as if folded, and the slit forming blade 4a opens the exposure opening. As can be clearly seen in FIG. 4, the thickness of the thin plate 12 is larger than the dimension in which the inclined portion 9b projects toward the traveling road side of the leading blade group 4 (theoretically, the same dimension does not matter). The cover blade 4e of the leading blade group 4 adjacent to the intermediate plate 9 always slides while being in contact with the thin plate 12 and does not collide with or scrape against the inclined portion 9b. Therefore, the cover blade 4e cannot be damaged. However,
Since the thin plate 12 is in sliding contact with the cover blade 4e, the cover blade 4
In order to prevent the surface of e from being scratched due to friction or the like and causing light leakage, it is preferable to use a synthetic resin sheet that is softer than the material of the cover blade 4e, and the surface of the cover blade is covered with a cover blade. It is preferable to apply a coating treatment that is softer than the surface of 4e.

As described above, the trailing blade group 7 starts traveling downward from the position shown in FIG. 1 after a lapse of a predetermined time after the leading blade group 4 starts exposure traveling. The exposure traveling of the trailing blade group 7 is performed by a pin of a trailing blade driving member (not shown) fitted in the hole 5a of the driving arm 5. Rear blade group 7
With this running, the slit forming blade 7a is at the front and the fan is widened to cover the exposure opening. Immediately before the front end of the slit forming blade 7a closes the exposure opening, the rear blade group 7 has a small overlapping amount with each other, and in FIG. Therefore, each blade of the trailing blade group 7 is easily bent in the plate thickness direction by a slight impact. At this time, the front blade group 4
When the brake is applied or stopped by the braking device, the vibration causes the slit forming blade 7a to be deformed, and the central portion thereof may be curved toward the intermediate plate 9. In that case, the slit forming blade 7a may be bent. The leading edge of is guided by the inclined portion 9b of the intermediate plate 9 and descends, reaches the position of FIGS. 5 and 6 and stops.

In the embodiment, the length of the inclined portion 9b is slightly shorter than the length of the long side of the opening edge 9a of the intermediate plate 9, but in practice, it may be a little shorter. On the contrary, the length may be equal to or longer than the long side. Further, in the embodiment, the thin plate 12
The length in the longitudinal direction of the intermediate plate 9 is longer than the long side of the opening edge 9a of the intermediate plate 9, but in the present invention, it is possible to make the length shorter than the long side. However, in order not to damage the cover blade 4e of the front blade group 4, the inclined portion 9
The length is preferably equal to or longer than the length of b. Further, in the present invention, the thin plate 12 covers the blade 4
Before contacting e, a groove may be formed in a streak shape so that the covering blade 4e can slide smoothly. It goes without saying that the leading blade group 4 may be arranged so that the slit forming blade 4a is located on the intermediate plate 9 side.

[0014]

As described above, according to the present invention, among the opening edges formed in the intermediate plate in a substantially rectangular shape, the edge in the exposure running direction of each blade group is set as the running path of the leading blade group. An inclined portion is formed so as to project toward the outside, and at a position where it comes into sliding contact with a cover blade arranged in a position close to the intermediate plate in the front blade group,
Since the thin plate is arranged so as to be in contact with the intermediate plate, the slit forming blades of the rear blade group do not collide with the intermediate plate and are damaged, and the cover blades of the leading blade group have no possibility of being damaged by the intermediate plate. .

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention showing a set state of a shutter.

FIG. 2 is an enlarged view of the right side surface of FIG.

3 (a) to 3 (f) are front views of main components excluding a blade group in the embodiment.

FIG. 4 is an enlarged view of a right side surface of a main part showing a halfway state of the opening operation of the leading blade group.

FIG. 5 is a front view of the embodiment showing an exposure end state.

FIG. 6 is an enlarged view of the right side surface of FIG.

[Explanation of symbols]

1 Substrate 1a, 9a, 11a Opening edge 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k
Shafts 2, 3 Leading blade arms 3a, 5a, 11b, 11c, 11h, 11i
Hole 4 Leading blade group 4a, 7a Slit forming blades 4b, 4c, 4d, 4e, 7b, 7c, 7d, 7e
Cover blades 5, 6 Rear blade arm 7 Rear blade group 8 Rear blade pressing plate 9 Intermediate plate 9b Inclined portion 10 Front blade pressing plate 11 Auxiliary substrate 12 Thin plate

Continued front page       (56) Reference JP-A-58-217919 (JP, A)                 Actual Kaihei 5-17633 (JP, U)                 Actual Kaihei 4-98033 (JP, U)

Claims (3)

(57) [Claims] 1. A first substrate, an intermediate plate, a second substrate, which are provided with respective substantially rectangular opening edge edges for forming an exposure opening and are sequentially arranged so that these opening edge edges overlap each other, and a slit formation. A front blade group having a blade and a cover blade arranged between the second substrate and the intermediate plate; and a slit forming blade and a cover blade arranged between the first substrate and the intermediate plate. And a rear blade group, and at least a part of the opening edge formed in the traveling direction of each blade group out of the opening edges provided on the intermediate plate is an inclined portion protruding toward the second substrate side,
Further, the thin plate is arranged so as to be in sliding contact with the blade closest to the intermediate plate in the front blade group outside the inclined portion as viewed from the exposure opening. 2. The thin plate has a thickness that is substantially the same as or larger than the dimension in which the inclined portion extends to the second substrate side, and is a direction along the opening edge where the inclined portion is formed.
2. The length of the groove has a geometrical dimension longer than the length of the portion where the inclined portion is formed.
Off O over Culp Ren shutter according to. 3. The thin plate is made of a synthetic resin sheet, and its surface is coated with a softer coating than the surface of the blade closest to the intermediate plate in the front blade group. off O over Culp Ren shutter according to claim 1 or 2.