Improvements in Iris Mechanisms.
Year: 1898

page_text: Improvements in Iris Mechanisms.
I, ERNST MAX BERGER, of Carl-Zeiss-Strasse 1, Jena, Grand-duchy of Saxe-
Weimar, Germany, Engineer, do hereby declare the nature of this invention
to be as follows:-
The invention consists in an improved iris mechanism for use in optical
apparatus and instruments. The improved iris may be arranged either so that
its aperture cannot be reduced farther than to a fixed minimum value or so that
it is capable of being completely closed. Therefore it may be used in any lens
system as a diaphragm the aperture of which is adjustable or it may serve as a
shutter for photographic objectives or finally it may be combined with a
photographic
lens system so as to serve for both purposes simul-
taneously. This iris is of very simple construction and consequently cannot
easily become inoperative. Furthermore, requiring but little space in the
direction of the optical axis, it is well adapted for being inserted between the
lenses of a photographic double objective.
To attain these purposes the iris consists of two annular groups of wings or
blades arranged one behind the other. The blades of both groups or halves of the
iris are mounted to swing in the same sense and the blades of each half always
cover the gaps between the blades of the other half. The blades of each half
of the iris lie all in one single plane being swung in the same plane, and on the
inner side their plane surfaces are in contact with the inner plane surfaces of the
blades of the other half in the median plane of the total iris, so as to produce a
continuous circumference of the aperture. The iris is very thin, as the blades
of each half do not overlap each other nor are otherwise superposed as in former
iris mechanisms.
An iris constructed as described permits to confine the adjustable aperture by
a closed line, which lies in one single plane perpendicular to the optical axis and
therefore presents an identical aperture not only for the rays which are parallel
to the axis but also for all oblique rays. For this purpose the blades, where
they surround the aperture, are beveled at their outer side, so as to form sharp
edges lying all in the above mentioned median plane of the iris. In case of a
totally closing iris (an iris-shutter) the central gap, which remains when both
halves of the iris are closed, is covered by a disk-like lid formed on the free end
of one of the blades or of one blade in each half.
1000

page_text: I, ERNST MAX BERGER, of Carl-Zeiss-Strasse 1, Jena, Grand-duchy of Saxe-
Weimar, Germany, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The invention consists in an improved iris mechanism for use in optical
apparatus and instruments. The improved iris may be arranged either so that
its aperture cannot be reduced farther than to a fixed minimum value or so that
it is capable of being completely closed. Therefore it may be used in any lens
system as a diaphragm the aperture of which is adjustable or it may serve as a
shutter for photographic objectives or finally it may be combined with a
photographic lens system so as to serve for both purposes simul-
taneously. This iris is of very simple construction and consequently cannot
easily become inoperative. Furthermore, requiring but little space in, the
direction of the optical axis, it is well adapted for being inserted between the
lenses of a photographic double objective.
To attain these purposes the iris consists of two annular groups of wings or
blades arranged one behind the other. The blades of both groups or halves of the iris
are mounted to swing in the same direction of rotation and the blades of each half
always cover the gaps between the blades of the other half. The blades composing
an annular half of the iris lie all in one single plane and are swung in this plane. On
one side their plane surfaces are in contact-in the median plane of the total iris-
with the plane surfaces of the blades of the other half, so as to produce a continuous
circumference of the total aperture. The iris is very thin, as the blades of each
half do not overlap each other nor are otherwise superposed as in former iris
mechanisms.
With an iris constructed as described the adjustable aperture may be confined by
a closed line, which lies in one single plane perpendicular to the optical axis, and
therefore presents an identical aperture not only for the rays which are parallel
to the axis but also for all oblique rays. For this purpose the blades, where
they surround the aperture, are beveled at their outer side, so as to form sharp
edges lying all in the above mentioned median plane of the iris. In case of a
totally closing iris (an iris-shutter) the central gap, which remains when both
halves of the iris are closed, is covered by a disk-like lid formed on the free end
of one of the blades or of one blade in each half.
The four figures of the annexed drawings represent the invention as applied to
a totally closing iris. Fig. 1 is a section through the iris casing perpendicular
to the optical axis and shows both halves closed; Fig. 2 is an axial section on
line 2-2 of Fig. 1. Fig. 3 is a section similar to Fig. 1, but both halves of the
iris being opened to form an aperture of middle size; Fig. 4 is a like section
showing the iris fully open.
In the example shown each half of the iris is composed of five blades, the
blades of one half being designated by the odd numbers 1, 3, 5, 7, 9 and the
blades of the other half by the even numbers 2, 4, 6, 8, 10. All ten blades by
means of pins a¹
provided at their outward ends engage with holes of the
driving ring b. A slot c in the casing d allows the operating pin e of the driving
ring to project outwardly. The pins a², a, a, as, a¹0 do not prevent the blades 2,
4, 6, 8 10 from sliding upon the driving ring e and upon the inner rim f of the
casing d, whilst the pins a¹, a³, a³, a², a³ hold the blades 1, 3, 5, 7, 9 at a distance
away from the driving ring and the said rim which is equal to the thickness of the

page_text: blades 2, 4, 6, 8, 10, so that the blades of each half of the iris guide each other by
means of their plane surfaces lying in the common plane of contact (in the median
plane of the total iris). The blades 1, 3, 5, 7, 9 slide with their outward surfaces
upon the inner rim of the cover of the casing. For swinging the blades
relatively to the driving ring e when this ring is shifted, each blade engages by
The
means of a second pin with a guiding groove arranged on the casing.
pins 22, 24, 26, 28, 10 of the 'even-numbered blades engage with the grooves ², ²,
,, in the casing d, and the pins 1, 3, 25, 27, 29 of the odd-numbered blades
engage with the grooves ¹, h, k, k, k¹, in the cover h.
110
The edge of each blade is partly beveled as shown at (Fig. 4.) 11. .
so that the sharp edges of all blades cooperate to form a closed bordering line for
the aperture, all parts of this line being situated in the median plane of the iris.
Blades 1 and 6 carry at their inner ends disk-like extensions or lids m¹ and m
respectively, which are designated to cover the central gap of the closed iris and
are beveled or form a shoulder at the inner side so as not to interfere with the
beveled outer surfaces of the adjacent blades overlapped by them.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. An iris mechanism consisting of two annular halves arranged one behind
the other, so that the blades of one half cover the gaps of the other half, the
blades of each half lying all in one single plane and swinging in the same plane
and the adjacent surfaces of both halves sliding upon each other in the median
plane of the total iris so as to produce a continuous circumference of the aperture,
essentially as described.
2. An iris mechanism of the kind characterized in Claim 1, the blades of which
have beveled outer surfaces so that the aperture is bordered by one single line
situated in the median plane of the iris, essentially as and for the purpose described.
3. The general arrangement of the iris mechanism as described in the fore-
going specification and shown in the annexed drawings.
Baal his Old love of Al 1800
WM. BROOKES & SON,
55 and 56, Chancery Lane, London, Agents for the Applicant.