JPH06265972A - Diaphragm device - Google Patents

Abstract

PURPOSE:To enhance diaphragming accuracy by a diaphragm blade by pressing a dowel pin in the diameter direction of a diaphragm hole by a pressing member, pressing it to the circumferential edge of a guide hole and eliminating backlash between the dowel pin and the guide hole. CONSTITUTION:The diaphragm blade 12, a holding ring 14 and an inner clip washer 16 are fitted to a diaphragm frame body 18. When the dowel pin 24 is pressed in the central direction of the diaphragm hole by a rubber band 28, the pin 24 is constantly pressed to the inside edge surface of the guide hole 26 by the restoring force of the band 28. Thus, the backlash by the engagement of the pin 24 and the hole 26 is eliminated. When the washer 16 is fluctuated clockwise or counterclockwise with an optical axis 30 as a center under such a state, the pin 24 of the blade 12 is slid along the hole 26 of the washer 16 without backlash and the diameter of the diaphragm hole is precisely expanded and reduced.

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 optical equipment such as cameras and video cameras.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a diaphragm device of this type has a plurality of diaphragm blades 1 (only one diaphragm blade is shown in FIG. 5) between a retaining ring 2 and a chrysanthemum 3. The holding ring 2 and the chrysanthemum 3 are superposed so as not to interfere with each other and are fixed to the diaphragm frame 4. A shaft pin 5 is planted in the base end portion 1a of the diaphragm blade 1, and the shaft pin 5 is rotatably attached to a bearing hole 6 formed in the holding ring 2 to form the diaphragm blade 1.
Is swingably positioned on the holding ring 2. Further, a dowel pin 7 is planted on the opposite side of the shaft pin 5 in the diaphragm blade 1, and the dowel pin 7 is engaged with a long hole-shaped guide hole 8 formed in the chrysanthemum seat 3.

When the chrysanthemum 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 to cause the diaphragm blade 3 to move. Is the optical axis 9 with the shaft pin 5 as a swing fulcrum.
The optical axis 9 or the 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, due to the rattling caused by the engagement between the dowel pin 7 of the diaphragm blade 1 and the guide hole 8 of the chrysanthemum 3, a diaphragm value in the direction of reducing the diaphragm diameter is set. Since there is a deviation from the aperture value in the direction of increasing the aperture diameter, there is a drawback that the aperture accuracy is poor. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a diaphragm device capable of improving diaphragm accuracy by eliminating rattling of a diaphragm blade and a chrysanthemum.

[0005]

According to the present invention, in order to achieve the above object, a plurality of diaphragm blades are superposed and held between a retaining ring and a chrysanthemum, and each diaphragm blade is provided in each diaphragm. The shaft pin is rotatably attached to the bearing hole formed in the retaining ring to be pivotally positioned on the retaining ring, and the dowel pin provided on each diaphragm blade is formed on the chrysanthemum seat. In a diaphragm device which is guided through a hole and swings each diaphragm blade according to the guide hole by rotating a chrysanthemum, the aperture of the diaphragm hole is expanded or contracted. It is characterized in that a biasing member is provided for biasing the dowel pin in the radial direction of the hole and pressing the dowel pin against the peripheral edge of the guide hole.

[0006]

According to the present invention, the dowel pin is pressed against the peripheral edge of the guide hole of the chrysanthemum by biasing the dowel pin in the radial direction of the throttle hole with the biasing member. Further, the biasing member is composed of an elastic member, and this elastic member is stretched over all the dowel pins, and even when the aperture diameter is the minimum, the restoring force of the elastic member pushes the dowel pin toward the center of the aperture hole. I tried to urge it. 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 diaphragm precision by the diaphragm blade is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a diaphragm device according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an assembled perspective view of a diaphragm device 10 according to the present invention, and FIG. 2 is a sectional view of an essential part after assembly. As shown in FIG. 1, a plurality of diaphragm blades 12 formed in a substantially crescent shape (only one diaphragm blade is shown in FIG. 1) include a donut-shaped holding ring 14 and a chrysanthemum 16 together with a rubber band 28 described later. It is held so that it does not interfere with it. In addition, the diaphragm blade 12 has a holding ring 14
And the chrysanthemum 16 are fixed to a diaphragm frame 18 formed in a tubular shape.

A shaft pin 20 is embedded in the base end portion 12a of the diaphragm blade 12. The shaft pin 20 is rotatably attached to a bearing hole 22 formed in the holding ring 14. As a result, the diaphragm blades 12 are swingably positioned on the holding ring 14. The diaphragm device 10 of the present embodiment is
Since the bearing holes 22 are formed in the retaining ring 14 at six positions, six diaphragm blades 12 are used.

A dowel pin 24 is planted on the diaphragm blade 12 on the opposite side of the shaft pin 20. The dowel pin 24 is a long hole-shaped guide hole 2 formed in the chrysanthemum seat 16.
6 is engaged. The rubber band 28 is expanded from the original shape shown by the solid line in FIG.
As shown in FIGS. 2 and 3, the dowel pins 24, 24 ... As a result, the dowel pins 24, 24 ...
Is urged toward the center of the aperture 32 by the restoring force of the rubber band 28. The dowel pins 24, 24 ... Are urged toward the center of the throttle hole 32 by the restoring force of the rubber band 28 even when the throttle hole 32 has the minimum aperture diameter shown in FIG.

Next, the diaphragm device 10 configured as described above.
The action of will be described. First, the diaphragm blade 12, the retaining ring 14, and the chrysanthemum 16 are attached to the diaphragm frame 18 as shown in FIG. 2, and the dowel pin 24 is urged toward the center of the diaphragm hole 32 by the rubber band 28. It is constantly pressed against the inner edge of 26. This eliminates rattling due to the engagement between the dowel pin 24 and the guide hole 26.

In this state, the chrysanthemum 16 is attached to the optical axis 3 shown in FIG.
When rotated clockwise about 0, the diaphragm blades 12
The dowel pin 24 slides along the guide hole 26 of the chrysanthemum 16 without rattling, and the diaphragm blade 12 swings in the direction of the optical axis 30 with the shaft pin 20 as a swing fulcrum. As a result, the aperture 3
The diameter of 2 is reduced as shown in FIG. Also, the throttle hole 3
When the diameter of 2 is enlarged, the chrysanthemum 16 is rotated counterclockwise around the optical axis 30. As a result, the dowel pin 24 slides along the guide hole 26 without rattling, and the diaphragm blade 12 uses the shaft pin 20 as a swing fulcrum to rotate the optical axis 3.
Since it swings in the direction away from 0, the diameter of the throttle hole 32 is enlarged as shown in FIG.

Therefore, in this embodiment, since the dowel pin 24 slides along the guide hole 26 of the chrysanthemum 16 without rattling at the time of expanding or contracting the aperture diameter, the aperture value in the direction of reducing the aperture diameter and the aperture diameter. And the aperture value in the direction of enlarging. Thereby, the diaphragm accuracy can be improved as compared with the conventional diaphragm device. In this embodiment, the rubber band 28 is used as the urging means for urging the dowel pin 24, but the present invention is not limited to this, and a substantially C-shaped steel wire member having elasticity may be used. .

Further, in the present embodiment, the dowel pin 24 is pressed and biased toward the center of the throttle hole 32, but the present invention is not limited to this, and the dowel pin 24 may be pressed against the inner edge surface of the guide hole 26. May be in the other direction.

[0014]

As described above, according to the diaphragm device of the present invention, since the dowel pin is biased by the biasing member to the peripheral edge of the guide hole, the rattle between the dowel pin and the guide hole is eliminated. You can do it. As a result, it is possible to improve the diaphragm precision of the diaphragm blades. Further, since an elastic member is used as the urging member and all the dowel pins are stretched by this elastic member to press and urge the dowel pin to the peripheral edge of the guide hole, it is possible to eliminate rattling between the dowel pin and the guide hole. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a diaphragm device according to the present invention.

FIG. 2 is a sectional view of an essential part of a diaphragm device according to the present invention.

FIG. 3 is an explanatory view showing an open state of the diaphragm device according to the present invention.

FIG. 4 is an explanatory view showing a closed state of the diaphragm device according to the present invention.

FIG. 5 is a perspective view showing an embodiment of a conventional diaphragm device.

[Explanation of symbols]

 10 ... Throttle device 12 ... Throttle blade 14 ... Holding ring 16 ... Chrysanthemum 18 ... Throttle frame 20 ... Shaft pin 22 ... Bearing hole 26 ... Guide hole 28 ... Rubber band

Claims (2)

[Claims] 1. A plurality of diaphragm blades are overlapped and held between a retaining ring and a chrysanthemum, and each diaphragm blade is rotated by a shaft pin provided in each diaphragm in a bearing hole formed in the retaining ring. By being freely attached, it is swingably positioned on the retaining ring, and the dowel pins provided on each aperture blade are guided through the guide holes formed on the chrysanthemum, and each is rotated by rotating the chrysanthemum. In a diaphragm device that expands and contracts the aperture diameter of a diaphragm hole by swinging the diaphragm blade according to the guide hole, the dowel pins provided on each diaphragm blade are urged in the radial direction of the diaphragm hole to move the dowel pin into the guide hole. A diaphragm device comprising an urging member for pressing and urging the periphery of the iris. 2. The urging member is an elastic member stretched over all the dowel pins so as to urge the dowel pins toward the center of the iris hole even when the iris has the smallest iris diameter. The diaphragm device according to claim 1, wherein: