JPH0714978Y2 - Diaphragm device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a diaphragm device used in a camera or the like, and more specifically, to a base plate having an opening formed in the optical axis and a position facing the base plate. A cover that is arranged and similarly has an opening formed on the optical axis, and a plurality of diaphragm blades that are movably supported between the base plate and the cover and that change the opening area of the opening are provided. The present invention relates to a diaphragm device.

[Prior Art] A typical conventional example of a diaphragm device having a plurality of diaphragm blades is described in Japanese Utility Model Laid-Open No. Sho 63-188639. As shown in FIG. 3, in this diaphragm device, diaphragm blades 4 and 5 which are movable in the left-right direction in the drawing are supported by a main plate 2. The base plate 2 also has an opening 10 on the optical axis, and the cover 3 also has an opening on the optical axis. Then, between the base plate 2 and the cover 3, the above-mentioned diaphragm blades 4,
5 is provided slidably.

In order to guide the diaphragm blades 4 and 5 to the left and right in the figure,
The blades 4 and 5 have a pair of long grooves 41 having a predetermined length in the longitudinal direction.
A, 41b, 51a, 51b are formed respectively. The base plate 2 is provided with guide pins 2a, 2b, 2c and 2d which are inserted into the respective long grooves to guide the diaphragm blades.

Therefore, when the drive pin 6a inserted in the long holes 4b and 5b is driven, the diaphragm blades 4 and 5 are guided by the guide pins 2a to 2d and slide in the left-right direction to appropriately adjust the opening area of the opening 10. It can be adjusted.

[Problems to be Solved by the Invention] As described above, since the long grooves 41a, 41b and 51a, 51b are formed at intervals in the sliding direction and the guide pins are also provided at intervals, the diaphragm blades 4 It has the advantage that it is accurately guided when the 5, slides. That is, there is a feature that it is guided without shaking in the direction perpendicular to the sliding direction.

However, since the long grooves 41b and 51b are located near the sides of the opening 10, there is a problem that the width h _{11 of the} diaphragm device becomes large. Although not shown in the drawing, in the case of the swing type, the diaphragm blades are inclined, so that the width h _{11 of the} base plate becomes wider accordingly. For example aperture when using φ0.8mm guide pin 2a~2b by restriction of the minimum thickness of the elongated groove and an outer diameter of the blade, the minimum width h ₁₃ of the long groove 41a~51b parts are needed than 2.4 mm. If the thickness of the side wall of the main plate and the gap between the blades and the main plate are included, h will have a width of 3.5 mm or more. For this reason, when the aperture opening diameter is 12 mm, the base plate width h ₁₁ becomes 19 mm, which requires a width of about 1.6 times the opening diameter. Therefore, an object of the present invention is to provide a diaphragm device in which the width of the base plate does not become large and the entire optical device such as a camera can be made compact.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a long groove formed in a diaphragm blade at a position avoiding the aperture forming portion, that is, a position closer to the driving side from the opening side. Individually formed. The guide pin that is inserted into the long groove and guides the diaphragm blade is configured to have a width of a predetermined length in the longitudinal direction of the long groove.

[Operation] Since the present invention has the above-mentioned means, when the drive pin is driven, the diaphragm blade slides while being guided by the guide pin, that is, the long groove being guided by the guide pin. Therefore, the opening area of the opening can be adjusted.

By the way, according to the present invention, since the guide pin has a width of a predetermined length in the longitudinal direction of the long groove, it can be smoothly guided without rolling when sliding. Moreover, since the long groove of the diaphragm blade is formed at a position away from the aperture forming portion,
The width of the base plate can be narrowed, that is, the diaphragm device can be made compact.

[Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
The same elements as those of the conventional example shown in FIG.

Now, with reference to FIG. 1 (a), it can be understood at a glance that the long grooves 4a and 5a according to the present embodiment are provided for each of the diaphragm blades 4 and 5. These long grooves are located at positions avoiding the opening 10, that is, the narrowed portion of the diaphragm blade 4.
It is also easily understood that it is formed at a position close to the driving side while avoiding h ₄ . Furthermore, it is understood that the guide pins 2a, 2b inserted into these long grooves also have a predetermined length l ₁ in the longitudinal direction of the long grooves 4a, 5a.

According to this embodiment, as shown in FIG.
A clearance of about 0.005 to 0.01 is provided between the width h _{3 of the} 5a and the guide pin h ₂ . Therefore, when the diaphragm blade 5 is slid by the drive pin 6b, the blade slides while swinging in the direction perpendicular to the longitudinal direction according to the length l ₁ of the guide pin 2b due to this clearance. Therefore, the diaphragm blades 4 and 5 may come into contact with the base plate 2.

However, according to this embodiment, both side walls 21 and 2 of the main plate 2 are
In particular, as shown in (d) of FIG. 1, 2 is formed with circular claw-shaped projecting portions 2c, 2d projecting toward the diaphragm blades 4 and 5, so that even if it shakes as described above, The blades 4 and 5 are smoothly guided by being restricted by these protrusions.

The effect of this embodiment will be explained by increasing the numerical value.
Since 4a is formed at a position avoiding the narrowed portion h of the blade 4, if the opening diameter φD is 12 mm, the width of the unit, that is, the width h ₁ of the main plate can be reduced to about 16 to 17 mm, and the conventional width 19
It can be about 10% smaller than mm.

Next, a second embodiment of the present invention will be described with reference to FIG.
The same components as those shown in FIG. 1 are designated by the same reference numerals, and duplicated description will be omitted.

According to the present embodiment, the base plate 2 has guide pins 2b ′, 2b ″.
, Are provided at intervals of 1 ₁ ′ in the longitudinal direction.
That is, two grooves are provided for one long groove 5a. Therefore, the interval l ₁ 'corresponds to the length of the guide pin, and the lateral movement of the diaphragm blade is restricted by these pins to guide the diaphragm blade. By increasing the distance l ₁ ′, the clearance between the widths h ₃ ′ and h ₂ ′ can also be increased.

[Advantages of the Invention] As described above, according to the present invention, since the long guide groove formed in the diaphragm blade is provided at a position apart from the opening on the optical axis, the width of the main plate can be reduced to reduce the diaphragm. The device can be downsized. Moreover, since the guide pin has a predetermined length in the longitudinal direction of the long groove, when the diaphragm blade is guided by the guide pin, it is guided without shaking even though there is only one long groove.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of the present invention, (a) is a top view thereof, (b) is a sectional view taken along line XX ′ in (a),
(C) and (d) are enlarged views of the portions surrounded by A and B in (a), and FIG. 2 is a view showing a second embodiment of the present invention, in which (a), (b), ( c) and (d) are top views, sectional views and enlarged views corresponding to (a), (b), (c) and (d) of FIG. 1, respectively, and FIG. 3 is a top view showing a conventional example. is there. 2 ... Base plate, 3 ... Cover 4,5 ... Diaphragm blades, 4a, 5a ... Long groove 10 ... Opening 2a, 2b, 2a ′, 2b ′, 2a ″, 2b ″ …… Guide pin.

Claims (1)

[Scope of utility model registration request] 1. A base plate having an opening formed on the optical axis,
A cover, which is arranged at a position facing the base plate and similarly has an opening formed on the optical axis, and a plurality of which are movably supported between the base plate and the cover and which change the opening area of the opening. A diaphragm device having a diaphragm blade, and a long groove is formed in the blade at a position closer to the driving side from the opening side, and the blade is inserted into the long groove provided in the main plate to guide the blade. The guide pin has a width of a predetermined length in the longitudinal direction of the elongated groove.