An Improved Electrical Apparatus for Reproducing Images of Distant Objects.
Year: 1895

page_text: Date of Application, 28th Feb., 1895-Accepted, 30th Mar., 1895
COMPLETE SPECIFICATION.
An Improved Electrical Apparatus for Reproducing Images of
Distant Objects.
I, ROBERT BERGLUND, of 8 Kammakaregatan, Stockholm, Sweden, Mechanical
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 :-
This invention relates to apparatus for reproducing at one place or station the
image of objects, which are within the range of activity of a transmitting apparatus
at another place or station, by the use at the latter place or station of a material
sensitive to light in combination with an electric circuit including a suitable
illuminating device at the receiving station and thus rendering it possible for a
person at one station in an electric circuit, to view objects at another station in
such circuit.
This apparatus is preferably termed a telephotograph, because it receives the
images of the objects at the one station directly and also directly reproduces these
images at the other station.
The transmitting and receiving instruments are alike with certain exceptions,
hereinafter mentioned.
In the accompanying drawing I have shown the essential parts of an apparatus
constructed according to my said invention.
S is a small block or point of selenium or other material which is similarly very
sensitive to light and of a good electrical conductivity. This point is placed in the
centre of the field or image-surface of a rigid but adjustable lens L forming the
objective of the apparatus. By means of the conducting wires, an electric
current from a suitable electric generator is passed through this point S, which
is fixed at the front end of a metallic tube p; this tube slides on a rod a and is
provided at its opposite end with a plate b. In the said tube near the plate bis
formed a small slot in which works a pin e secured to the rod a; between the pin e
and the plate bis arranged a spring for pressing the plate against a ring or coller B
secured to a frame A.
The frame contains a Cardan's or gimbal joint in which the said rod a is
supported in such a manner that it can be moved horizontally as well as
perpendicularly.
On the rear end of the rod a is mounted a bent lever m which can be turned
around the rod but is not free to slide longitudinally thereon. The upper end of
this lever is provided with a block or piece n, sliding in a guide d, arranged in the
surface of a conical piece or cap D and in the direction of its generatrix. This
cap D is fixed on one end of a horizontal shaft E the opposite end of which slides
in or is surrounded by the tubular part of the driving shaft F of the apparatus the
shafts E and being connected together by means of a pin and a guide-slot,
The shaft E is also provided with two flanges, forming a guide i for the fork-shaped
lower end of a lever K, and the driving shaft F is provided with a worm g gearing
with a worm-wheel G. On one face of this worm wheel is mounted an eccentric H,
which, by means of the connecting-rod, causes the lever K to oscillate as shown
by the dotted lines in the figure during the revolution of the wheel G. By means
of the guide i the lever K thus gives the shaft E a sliding movement forward and
backward, the length of travel of the said shaft being regulated by means of the
7.1

page_text: eccentric H. The cap D besides its revolving movement obtained from the driving
shaft, thus also receives a sliding motion causing the piece to slide up and down
in the slot of the cap D. This movement is transmitted to the rod a by means of
the lever m in such a way that the forward end of the said rod a carrying the point
of selenium is moved in a spiral line, the coils of which are close to each other.
This spiral, by the action of the tube the plate and the spring will be situated
in the field or image surface of the lens. During this spiral motion the selenium
point consequently successively catches all the light impressions of which the image
of the object viewed consists. and the varying strength or intensity of which
produces its lights and shadows.
But at every such variation of the light impression on the selenium point the
strength of the electric current in the circuit also changes, thus varying the strength
of the current at the receiving instrument.
This apparatus, instead of a selenium point or similar material which is sensitive
to light, is provided with a very small Geissler tube or incandescent lamp, very
sensitive to variations of the electric current, which lamp is moved in the field or
image surface of the lens of the receiving apparatus in the same manner as the
point of selenium at the transmitting station. By means of the varying strength or
intensity of this light at the receiving station, an image will consequently be
produced similar to that at the transmitting station, which image may be male
visible in different ways such as by a camera or by direct observation through a lens
or also by means of a sciopticou.
The apparatus above described is enclosed in a box or casing perfectly excluding
the light; except that passing through the lens. The lens may be adjusted to a
suitable distance from the selonium point (or from the incandescent lamp) by means
of a scale, arranged for varying distances in an experimental way, or by a ground-
glass or other screen in the same way as by a camera.
For setting the apparatus in motion any suitable motor may be used; the power
required to drive it is not great, but the speed evidently must be so regulated that
the intervals between the successive light impressions of the selenium point from
one and the same point of the image shall be not more than of a second, or so
that the corresponding light impressions in the eye of the spectator will produce a
continuous or complete image.
If it should be necessary to increase the strength of the current when arriving at
the receiving apparatus an induction coil may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1st. An electric apparatus for the purposes above specified, comprising, at the
transmitting station, an adjustable objective and a block or point of seleniuin or
analogous material included in an electric circuit and movable iu a spiral-line in the
image formed at the focus of the objective, and at the receiving station another
objective and an incandescent lamp or its equivalent movable in the same way as
the said block or point of selenium or other material and also included in an electric
circuit.
2ud. In an electric apparatus for the purposes above specified, the combination
of the objective, the block or point of selenium or analogous material or the
incandescent lamp or its equivalent, placed at the end of a tube sliding on a rod
capable of being turned both vertically and horizontally, a plate mounted on the
said tube, and pressed against a stationary collar or surface, a bent lever capable of
being turned about the inner end of the said rod but restrained from sliding
longitudinally, a piece or shoe on the outer end of this lever, sliding in a guide on
the surface of a conical or other piece or cap, the intermediate shaft of which slides
in the main shaft and moves therewith and means for communicating to the
intermediate shaft a sliding motion from the main shaft, substantially as described.

page_text: 3rd. The improved apparatus constructed substantially as described with
reference to the accompanying drawing, and operating as and for the purposes
above specified.
Dated the 28th day of February 1895.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.