JPS5860735A - Completely closed iris stop - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fully closed iris diaphragm having overlapping and interengaging iris blades, each having a bearing bin and a guide bin.

Existing fully closed iris diaphragms on the market have a protruding lug on the diaphragm blades on the edge defining the aperture of the diaphragm, which covers the remainder of the aperture. (British Patent No. 1.386.310) However, with such aperture blades, the desired approximately circular shape of the aperture cannot be achieved. This is inconvenient for obtaining images.

Other fully closed apertures on the market have a closing element that acts as an additional vane to close the remaining aperture by pivoting in front of the smallest possible aperture of the main aperture. are doing. (German Patent No. 2.31
6.812> In this design, the shutter cannot be adjusted continuously from its maximum aperture to zero aperture. Alternatively, the aperture can be closed to its maximum value and the remaining apertures can be closed without another intermediate value. Furthermore, due to the thickness of the stacked aperture blades, stray rays may enter.

Still other commercially available fully closed apertures have aperture blades located in parallel planes, the effective edge of the aperture being circular and larger than a semicircle. Above each aperture blade, at approximately diametrically opposite positions,
Aperture blade bearing pins and guide pins are located, said pins being fixed to radially projecting webs at both ends of the main portion of each aperture blade, said aperture blades being shaped primarily as a segment of a circular arc. have. The two ends of said main part have at their inner etch a continuous, arc-shaped extension, the radial width of which is smaller than that of the main part, and whose chord The length of the portion is such that adjacent extensions of the aperture blades located in parallel planes overlap each other in the fully open state. (German Patent No. 2.040.-884) In this implementation, it turns out that for functional and structural reasons the ideal number of diaphragm blades is five.

This is because if the number is other than this, the width of the aperture blade will be 5.
This is because the width of the aperture housing needs to be larger than the width corresponding to the aperture blades.Furthermore, the diameter of the aperture housing (D2)
There is also an upper limit on the diameter ratio of the diameter of the maximum aperture (Dl) to the diameter of the maximum aperture (Dl). Such limitations can be a major hindrance or preclude the use of such fully closed apertures in various applications. Other dimensions also increase, making such a shape unsuitable for many applications.

It is an object of the invention to provide a fully closed iris diaphragm which provides a substantially circular aperture from maximum diaphragm aperture to zero aperture. Furthermore, it should no longer be necessary to impose restrictions on the diameter ratio or the width of the diaphragm blades, which have been referred to up until now.

Furthermore, the overall thickness of the diaphragm structure is also very thin, and the center of the diaphragm can be closed reliably.

The above-mentioned problem can be successfully solved according to the present invention, since when the aperture is completely closed, the aperture blades intersect even at a distance from the center of the aperture, and at least the aperture blades that are similar to each other overlap. The diaphragm can be covered by one. Further, the iris diaphragm has the iris blades divided into two sets, each set of which is located on one side of the pivot adjustment mechanism in the diaphragm housing, and each iris blade is located on either side of the adjustment mechanism or the housing. The bearing pin of the first set of aperture blades can be constructed with a bearing pin that is pivotable on the aperture housing and a guide pin that is displaceable in the aperture housing jink or adjustment mechanism. may be arranged along a first semicircle, and the bearing pins of the second set of aperture blades may be arranged along a second semicircle, each of these semicircles being on opposite sides of the adjustment mechanism. It is located.

It is also advantageous if the guide bins are guided in radial grooves located within a semicircular arc of each adjacent part of the housing.

A guide bin for each aperture blade may be located near one end of the blade, and a bearing bin may be located near the other end.

Further details and advantages of the iris diaphragm forming the subject matter of the invention will be illustrated in the description of a functionally existing specimen with reference to the accompanying drawings.

A housing 1, which is made in almost the same type as the circular housing rings IL and IJJ, has a setting ring 2, and a setting arm 3 projecting from the housing 1 is connected between these rings 1' and 1''. It is located and rotated.

On the setting ring 2, the first
A set of diaphragm blades 4' and a second set of diaphragm blades 4'' on the other side are located in pivotal bearing relative to pivot pins 5' and 5'', respectively. The pivot pins 5' of the first set of diaphragm blades 4' are located in an arc on one half of the setting ring 2, and the pivot pins 5'' of the second set of diaphragm blades 4'' are arranged in a circular arc on one half of the setting ring 2. It is arcuate on the other half of the ring 2 and located on the second side of said ring. Said diaphragm blades are arc-shaped, preferably forming part of a circle, and at each other end have guide pins 6' and 6'', which are connected to the housing ring 1'.

1" radial groove 7.7", said radial groove 7' belongs to the first set of aperture blades 4' and is located in a semicircular arc. , and the radial groove 7
'' belong to the second set of aperture blades 4'' and are located along a semicircular arc in the second housing ring 1''.The aperture blades in each set are located in a plane intersecting each other. are doing.

The two housing rings 1', 1'' are removably connected to each other. On both sides of the setting ring 2 are thin guide plates 8'.

8" is the bearing bin 5' of the first aperture blade.

5'' and the guide bins 6', 6'' of each set of aperture blades, said guide bins intersect with the bearing surface of the aperture blades, and the aperture blades are located at the limits of their operating range. This prevents the aperture blades from moving when they are located close to each other, causing them to collide with each other and become stuck.

When the setting ring 2 in the housing 1 is rotated, the aperture blades 41 , 411 are driven by the bearing pins 5 ′, 5 ″ and slide according to the guide pins 6 + , B II in the radial grooves 77.7H, resulting in an effective The diameter of the aperture of the aperture blade (Dl) is increased or decreased.

For example, if there are a total of 12 aperture blades, an approximately circular aperture will be obtained no matter what the diameter of the aperture. When the aperture blades are completely closed,
The first and last aperture blades 8', 8' and B n of each set
, B n will cover the beam axis of the aperture of the aperture blade, thus closing the aperture blade.

Consequently, by placing the aperture blades on the two sides of the setting ring and by arranging the radial grooves, this iris diaphragm has a very thin housing structure, without introducing stray rays if necessary. Furthermore, the diameter ratio between (Dl) and D2) can be set to 1:1.15 or less. This is achieved by increasing the number of aperture blades.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a closed iris diaphragm, and FIG. 2 is a diagram showing the practical positions of the first and last blades of each set when the iris is closed. In the figure, 1...Housing 4J, 4 II...Aperture blades 5', 5''...Bearing bins 91.6++...Guide bins 7t, 7n...Radial grooves. Akira Asamura 4 people

Claims (1)

Claims: 1) A fully closed iris iris diaphragm with overlapping and interengaging iris blades, each of said iris blades having a bearing bin and a guide bin, which completely closes the iris; and complete closure, characterized in that, even at a distance from the center of the diaphragm, crossing points of the diaphragm blade etches are created, so that the diaphragm can be covered by at least one of the diaphragm blades which are similar to each other. iris aperture. 2. In the fully closed iris iris diaphragm as claimed in claim 1, the iris blades are divided into two sets, each set of which is connected to one side of a pivotable adjustment mechanism within the diaphragm housing. , the bearing pin of each aperture blade is located in a pivot bearing ring in either the adjustment mechanism or the housing, and the guide pin is displaceable in the aperture housing or adjustment mechanism. Completely closed iris diaphragm. 3) In the fully closed iris iris diaphragm according to claim 2, the bearing bins of the first set of diaphragm blades are arranged along the first semicircle, and the bearing bins of the second set of diaphragm blades are arranged along the first semicircle. fully closed iris diaphragms are arranged along a second semicircle, each of these being arranged on opposite sides of the adjustment mechanism. 4) In the completely closed iris diaphragm according to claim 2, the guide pin is guided along a radial groove in mutually adjacent parts of the housing, and the radial groove is a semicircular arc. A completely closed iris diaphragm exists inside the iris. 5) A fully closed iris diaphragm according to claim 2, wherein the guide bin is located near one end of each aperture blade, and the bearing bin is located near the other end.