JP3344429B2 - Aperture device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm device, and more particularly to a diaphragm device applied to an optical apparatus such as a camera or a video camera.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a diaphragm device of this kind has a plurality of diaphragm blades 1 (only one diaphragm blade is shown in FIG. 4) between a holding ring 2 and a chrysanthemum seat 3. They are superposed so as not to interfere with each other and fixed to the aperture frame 4 together with the holding ring 2 and the chrysanthemum seat 3. A shaft pin 5 is implanted at the base end 1a of the diaphragm blade 1. The shaft pin 5 is rotatably attached to a bearing hole 6 formed in the holding ring 2 so as to be rotatable.
Are pivotally positioned on the holding ring 2. A dowel pin 7 is implanted in the diaphragm blade 1 on the side opposite to the shaft pin 5, and the dowel pin 7 is engaged with a long hole-shaped guide hole 8 formed in the chrysanthemum seat 3.

When the chrysanthemum seat 3 is swung clockwise or counterclockwise about the optical axis 9, the dowel pin 7 of the diaphragm blade 3 moves along the guide hole 8, thereby causing the diaphragm blade 3 to move. Is the optical axis 9 with the shaft pin 5 as a pivot point.
Swings in a direction or a direction away from the optical axis 9. As a result, the aperture diameter can be enlarged or reduced.

[0004]

However, in the conventional diaphragm device, the aperture value in the direction of decreasing the aperture diameter is reduced by the engagement between the dowel pin 7 of the diaphragm blade 1 and the guide hole 8 of the chrysanthemum seat 3. However, since there is a deviation from the aperture value in the direction of increasing the aperture diameter, there is a disadvantage that the aperture accuracy is poor. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an aperture device that can improve aperture accuracy by eliminating play between an aperture blade and a chrysanthemum seat.

[0005]

According to the present invention, in order to achieve the above object, a plurality of diaphragm blades are held by being superposed between a holding ring and a chrysanthemum seat, and each diaphragm blade is provided in each diaphragm. The shaft pin is pivotally attached to a bearing hole formed in the holding ring so as to be swingably positioned on the holding ring, and a dowel pin provided on each aperture blade is provided in a guide hole formed in the chrysanthemum seat. In a diaphragm device which is guided through and rotates a chrysanthemum seat to swing each diaphragm blade according to the guide hole to expand and contract the diameter of the diaphragm hole, the diaphragm blade is urged in a radial direction of the diaphragm hole. And an urging member for urging the dowel pins provided on each of the aperture blades toward the periphery of the guide hole , wherein one end of the urging member is fixed to the holding ring.
And the other end is pressed against the diaphragm blade.
Is a leaf spring, and the shaft pin of the diaphragm blade is formed on the diaphragm blade.
Eccentric with respect to the center of the arcuate contact surface of the
And follow the swing of the aperture blade in the direction of reducing the aperture diameter.
And place it at a position where the distance from the
It is characterized by having been.

[0006]

According to the present invention, the dowel pin is pressed against the periphery of the guide hole of the chrysanthemum seat by urging the diaphragm blade in the radial direction of the diaphragm hole with the urging member. Further, the urging member is constituted by a leaf spring, and the diaphragm blade is urged by the leaf spring. As a result, the dowel pin slides along the guide hole in a state where there is no play with the guide hole, so that the aperture accuracy by the aperture blade is improved.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a diaphragm according to the present invention; Figure 1 illustrates the present invention
1 is an assembled perspective view of a diaphragm device 10 according to a reference example for the present invention.
As shown in the drawing, a plurality of diaphragm blades 12 formed in a substantially crescent shape (only one diaphragm blade is shown in FIG. 1) do not interfere between the donut-shaped holding ring 14 and the chrysanthemum seat 16. And are superimposed and held. In addition, the diaphragm blade 12
Is fixed together with the holding ring 14 and the chrysanthemum seat 16 to an aperture frame 18 formed in a cylindrical shape.

A shaft pin 20 is implanted at the base end 12a of the diaphragm blade 12. The shaft pin 20 is connected to the holding ring 1.
4 and is rotatably attached to a bearing hole 22 formed therein. As a result, the aperture blade 12 is pivotally positioned on the holding ring 14. In the aperture device 10 of the reference example, three aperture blades 12 are used because the bearing holes 22 are formed at three places in the holding ring 14.

A dowel pin 24 is implanted on the diaphragm blade 12 on the side opposite to the shaft pin 20.
Is engaged with a long guide hole 26 formed in the chrysanthemum seat 16. On the other hand, a leaf spring 28 is arranged between the holding ring 14 and the chrysanthemum seat 16. The leaf spring 28 has a proximal end 28 a fixed to the holding ring 14 and a central portion pressed against the peripheral edge of the proximal end 12 a of the diaphragm blade 12. As a result, the aperture blade 12 is moved by the biasing force of
The dowel pin 24 is pressed against the periphery of the guide hole 26 of the chrysanthemum seat 26 by being pressed and urged in the zero direction.

Next, the diaphragm device 10 constructed as described above is used.
The operation of will be described. First, the diaphragm blade 12, the holding ring 14, and the chrysanthemum seat 16 are attached to the diaphragm frame 18, and when the diaphragm blade 12 is urged in the direction of the optical axis 30 by the leaf spring 28, the dowel pin 24 becomes the inner surface of the guide hole 26. Pressed constantly. Thereby, the dowel pin 24 and the guide hole 2
The backlash is eliminated by the engagement with 6.

When the chrysanthemum seat 16 is rotated clockwise about the optical axis 30 in this state, the diaphragm blade 12 is set so that the dowel pin 24 of the spring member 28 is not loose along the guide hole 26 of the chrysanthemum seat 16. The diaphragm blade 12 slides and swings in the direction of the optical axis 30 with the shaft pin 20 as a swing fulcrum. Thereby, the diameter of the throttle hole 31 is reduced (see FIG. 2A). Further, the chrysanthemum seat 16 is rotated counterclockwise about the optical axis 30. As a result, the dowel pin 24 of the diaphragm blade 12 slides along the guide hole 26 without play, and the diaphragm blade 12 swings in the direction away from the optical axis 30 against the urging force of the leaf spring 28. The diameter of the throttle hole 31 increases (see FIG. 2).
(B)).

Therefore, in the reference example, the dowel pin 24 slides along the guide hole 26 of the chrysanthemum seat 16 without any backlash when the aperture diameter is enlarged or reduced, so that the aperture value in the direction of reducing the aperture diameter and the aperture diameter are reduced. The aperture value in the direction of enlargement becomes identical. Thereby, the aperture accuracy can be improved as compared with the conventional aperture device. FIG. 3 (a), description thereof is denoted by the same reference numerals in (b) shows the actual施例throttling device of the present invention, FIG. 1, the same members and reference example shown in FIG. 2 Omitted.

[0013] pivot pin of the diaphragm blade 32, which is applied to the real施例20, the center of which is formed at the base end portion 32a periphery of the diaphragm blades 32 arcuate surface 32b, i.e., the center of the contact surface of the plate spring 28 And at a position where the distance from the contact portion of the leaf spring 28 increases as the diaphragm blade 32 swings in the direction of reducing the aperture diameter. This allows
The pressing force from the spring member 28 received on the aperture blade 32 increases as the aperture diameter decreases.

[0014] Thus, the actual施例dowel pin 24, the pressing force is increased with respect to the guide hole 26 in accordance with aperture diameter is reduced, it can be eliminated reliably guide hole 26 gentlemen. Thereby, the aperture accuracy can be improved as compared with the conventional aperture device.

[0015]

As described above, according to the aperture device of the present invention, the dowel pin is pressed against the peripheral edge of the guide hole by urging the aperture blade in the radial direction of the aperture hole with the urging member. The play between the dowel pin and the guide hole can be eliminated. Further, since a leaf spring is used as the urging member, the aperture accuracy of the aperture blade can be improved with a simple structure. Furthermore, the dowel pin of the diaphragm device has a diaphragm aperture.
The pressing force against the guide hole increases as
The guide hole can be eliminated without fail,
Accuracy can be improved compared to conventional diaphragm devices
You.

[Brief description of the drawings]

Perspective view showing a reference example of FIG. 1 aperture Ri device

FIG. 2A is an enlarged view showing a closed state of a diaphragm device according to a reference example, and FIG. 2B is an enlarged view showing an opened state.

[3] FIG. 3 (a) is an enlarged view showing a closed state of the throttle device according to the actual施例of the present invention, and FIG. 3 (b) is an enlarged view showing the open state

FIG. 4 is a perspective view showing an embodiment of a conventional diaphragm device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Aperture device 12, 32 ... Aperture blade 14 ... Holding ring 16 ... Kikuza 18 ... Aperture frame 20 ... Shaft pin 24 ... Dowel pin 22 ... Bearing hole 26 ... Guide hole 28 ... Leaf spring

Claims (1)

(57) [Claims] 1. A plurality of diaphragm blades are superposed and held between a retaining ring and a chrysanthemum seat, and each diaphragm blade is rotatable in a bearing hole formed in the retaining ring with a shaft pin provided in each diaphragm. Is mounted on the holding ring so as to be swingable, and the dowel pins provided on each of the aperture blades are guided through guide holes formed in the chrysanthemum, and the respective aperture blades are rotated by rotating the chrysanthemum. The aperture device is oscillated in accordance with the guide hole to expand and contract the aperture of the aperture hole. The aperture blade is urged in the radial direction of the aperture hole, and a dowel pin provided on each aperture blade is set at the periphery of the guide hole. It includes a biasing member that presses and biases the, the biasing member has one end portion is fixed to the holding ring
The other end is pressed against the diaphragm blade to make contact with the plate.
A root, the axial pins of diaphragm blades, the diaphragm circular plate spring formed on the blade
At a position eccentric to the center of the arcuate contact surface, and
The leaf spring abuts as the blade swings in the direction to reduce the aperture diameter.
A diaphragm device which is planted at a position where the distance from the part is increased.