Circular Shutter for Optical Reflectors, Projecting Lanterns, and analogous Appliances.
Year: 1898

page_text: Date of Application, 7th Nov., 1898-Accepted, 23rd Dec., 1898
COMPLETE SPECIFICATION.
Circular Shutter for Optical Reflectors, Projecting Lanterns, and
analogous Appliances.
I, JASPER WETTER, Patent Agent, of 37 & 39, Essex Street, Strand, in the
County of London, do hereby declare the nature of this invention, a communica-
tion from abroad by the Elektrizitäts-Aktiengesellschaft vormals Schuckert & Co.,
Electrical Engineers, of Nürnberg, Bavaria, to be particularly described and
ascertained in and by the following statement: --
The special applications of reflectors, electrical projecting lanterns and analo-
gous appliances, render it desirable to provide devices for rapidly and completely
obscuring or intercepting the conical bundle of rays emanating from the same,
so that they may be set out of action without extinguishing the source of light,
or breaking the electric current which produces it. The devices hitherto employed
for this purpose suffer from the defect, that they allow light to pass through,
or that they are injured by the heat rays concentrated upon them."
"
The present invention has for its object, to provide an obscuring or intercept-
ing device for circular openings, especially those of reflectors, which device has
some resemblance to the well-known iris shutters of photographic cameras, and
which besides fulfilling the requirements mentioned above, can be handled with
ease, rapidity and certainty, and is therefore suitable also as a signalling device.
In the accompanying drawings, Figs. 1 to 3 are diagrams of the improved
shutter in different stages of operation, and Fig. 4 is an axial section of the same
on a larger scale, so as to show the details of construction.
The shutter chiefly comprises an annular frame of such a size, that it can be
mounted in the opening to be obscured: a set of sickle-shaped segments b₁, b₂,
ba, b, b, of sheet metal or other suitable material, arranged round the inner
circumference of the said frame, each segment being pivoted at one end on a
stud c, and connected at the other end by a short link or guide bar d₁, d...d, to
a ring e adapted to turn on the axis of the frame a; a ring e, as mentioned
above, mounted on balls f and provided with a handle g for turning it; a roller h
fixed in the centre of the ring e and coaxial with the same, said ring being pro-
vided with a deep circumferential groove k and secured in its position by three
suspension wires i placed at 120° to each other, or by other suitable means.
The width of the groove k increases from the centre towards the circumference
of the roller, as shown by Fig. 4.
When the shutter is fully open, as represented by Fig. 1, the segments 6, to b
partly overlap each other, and form a ring composed of several layers, because
the entire circumference of the frame a is provided with such segments. If the
ring e connected with the segments b₁... b, by the links d₁... d, is turned in the
direction of the arrow, the various segments are forced to approach the axis of
the frame a, Fig. 2. During this time the circular opening formed by the
segments is gradually getting smaller. until the segments .slide into the
groove formed by the roller h, and abut against the axle or
the same, while they are firmly pressed against each other, Fig. 3.
core of
As

page_text: the various segments overlap each other, without forming any clearance, this
opening of the frame a is completely obscured. In the case of electrical, reflector
lamps, the roller h in the axis of the reflector has little or no effect on the optical
effect, because the central part is already inoperative, owing to the shadow of
the negative carbon falling upon the same.
In cases, however, where the loss of light in the axis of the shutter must be
avoided, the stationary roller h may be replaced by a movable roller fixed to the
centre of one of the segments b. For opening or closing the shutter, the ring e
need not be turned more than 90°, as shown by experience, but the same effect
may be obtained by turning the ring e only 45°, if the frame a carrying the
pivots of the segments is adapted to turn also, and in a direction opposite to that
of the ring e.
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. A circular shutter for reflectors, projecting lanterns and analogous appli-
ances, constructed in the manner of iris shutters for photographic cameras, but
having in the centre a fixed roller h provided with a deep circumferential
groovek, substantially as and for the purpose described.
2. In circular shutters of the type specified, the combination of segments b,
with guide bars or links d, and ring e adapted to be turned by means of a handle,
substantially as and for the purpose described.
3. A circular shutter for reflectors, projecting lanterns and analogous appli-
ances, comprising in its construction a ring frame a, and a segment-carrying
ring e, mounted one within the other by means of a ball-bearing, so as to allow
a relative rotary motion, substantially as described.
4. A circular shutter for reflectors, projecting lanterns and analogous appli-
ances, constructed and adapted to operate as described and illustrated by the
drawings.
Dated this 7th day of November 1898.
FAIRFAX & WETTER,
Agents, 37 and 39, Essex Street, Strand, London.