Improvements in Plate-changing Apparatus for Photographic Cameras.
Year: 1890

page_text: Date of Application, 15th Jan., 1890-Accepted, 15th Feb., 1890
COMPLETE SPECIFICATION.
Improvements in Plate-changing Apparatus for Photographic
Cameras.
"
I, NEWNHAM BROWNE, of 73, Cheapside, in the City of London, Fellow of the
Institute of Patent Agents, do hereby declare the nature of the said invention for
"IMPROVEMENTS IN PLATE-CHANGING APPARATUS FOR PHOTOGRAPHIC CAMERAS
which invention has been communicated to me from abroad by Friedrich Auguste
Fichtner of Elisenstrasse 6, Dresden, Altstadt, in the King lom of Saxony and Empire
of Germany Cabinet maker and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The present invention relates to an arrangement or apparatus for application to
photographic cameras carrying several plates simultaneously, (such for instance as
are known as detective cameras) enabling an exposed plate to be rapidly changed for
a fresh or unexposed plate so that a fresh exposure may be made with a loss of a few
seconds only.
The said arrangement, shown in the accompanying drawings consists in the
following:
The camera is made of suitable width and contains two divisions or compartments
each containing half the number of plates to be carried by the camera.
Each plate
is carried by a frame or by other suitable means.
In the drawings a camera is shown intended to carry twelve plates, 6 in each
compartment and a are the frames or carriers for the plates.
On the rear of that compartment which faces the lens, and on the front of the .
second compartment springs b are arranged at top and bottom.
Each pair of these springs acts upon the frame of the plate nearest thereto and so
push such frame and the others behind it against the side of the compartment opposite
to the springs that the frame a of the foremost plate in the one case and the rear-
most in the other lays close to corresponding side of the compartment, whilst at the
other side (where the springs b are), space enough remains for one frame in each
compartment.
Between the two compartments a vertical arbor c is provided which is at the top,
outside the camera, fitted with a crank c¹. Above and beneath the plate carriers a
toothed wheels d and d¹ are provided on the arbor c, these wheels being cut alike.
Parallel to the frames a are pairs of toothed racks e and fand e¹ and f¹ engaging
with the wheels d, d¹. One pair of racks corresponds to the foremost plate, one to the
rearmost plate or frame a.
1
On each rack a spring 9, 9' and h, h¹, one of which is shown in detail in Fig. 6, is
provided the free ends of said springs being hook-shaped. The racks e, f and ef
are, by the wheels d, d¹ moved in opposing directions and the size and position of
the wheels must be determined so as to suit the camera.
The operation of this arrangement is as follows:
Suppose that the two racks engaging with the lower wheel d' are in the position shown
in fig. 5 so that they are underneath the foremost and the rear-most frames a respec-
tively and in their extreme position, then the racks gearing with d must be just above
the lower ones, i.e., the rack e above e¹ and f above f¹. When the racks are in this
position the hooks on the springs g, g¹, and h, ' enage with the corners of the frames
between them.
Now if, by means of the arbor c the wheels d d are rotated from right to left the
racks e, el and with them the plate a held by the springs 9, 9' will travel from right
to left and the racks f,f¹ with the plate or frame a held by the springs h, h¹ passes
from left to right.
Both the plates or frames thus set in motion find free access into that compartment
o which they are carried.

page_text: As each of the moving plates finds firm support in the others contained in the same
compartment it is enabled to depress the springs b, b. As soon as the outgoing plate
has left the compartment all the plates in the compartment, including the incoming
one are pushed forward (or backward) by the springs b acting on the frame last
arrived in the compartment until the outermost frame a bears against the side of the
compartment as shown in fig. 4. When the frames a in travelling reach the opposite
end of the camera they have assumed their final position. By the operation just
described an exposed plate has been moved from the compartment facing the lens to
the second compartment, and a fresh one from the second compartment to the first. If now
the wheels d, d' are turned from left to right the parts of the mechanism resume their
original position. When the return motion begins the hooks of springs g, g' and h, h
will by their inclined faces, slide under or over the frames and the springs fall into
grooves in the racks so that no obstacle to the movement of the latter is presented.
When the racks have again reached their original position (figs. 1 and 5) the com-
pression of the springs g, gland h, h¹ pushe sthe hooks forward and causes them to
engage with the frames for the next change.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed as communicated to me
by my foreign correspondent, I declare that what I claim is :
A device for changing photographic plates, consisting of an arbor c, the wheels d, d
mounted thereon, the racks e, e, f, f, for carrying the frames or plate carriers, and
the springs g, g, h, h¹ for holding the frames on the racks.
Dated the 14th day of January 1890.
NEWNHAM BROWNE.