Improvements in Photographic Cameras.
Year: 1890

page_text: Date of Application, 3rd Apr., 1890
Complete Specification Left, 5th Jan., 1891-Accepted, 14th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Photographic Cameras.
GEORGE DICKINSON 144 Morley Avenue Noel Park London N. Photographic
Salesman do hereby declare the nature of this invention to be as follows:-
In the accompanying drawings A represents any convenient number of straight
grooves at top and bottom of the camera radiating round the arcs of two circular
discs of the same diameters as the length of grooves; the said grooves being some-
what longer than the width of the sensitive plates to be used, and their distance
apart being determined by the size of the same. The two circular discs, having one
groove in each B bisecting the centres thereof, are connected by a partition C; this
takes the place of what is known in photographic language as the "slide" or "dark
slide." The plates are carried in the radial grooves A, and to bring them into
position for exposure, the camera must be held at such an angle as to allow the
particular plate desired to gravitate into the grooves B of the slide. This slide is
pivoted at top and bottom-the bottom pivot Ŏ passing through the frame of the
camera and bearing a milled head N, or other thumbpiece, by means of which the
slide can be turned so that the plate is brought into position to receive the image
from the lens. It is held there by means of a catch F being slid into notch G.
Fixed on either side of the slide are pieces of wood E' E" or other material one
projecting slightly over the front and the other over the back of the slide, forming
a partition across the entire camera with the object of preventing light passing to
any other plate than the one in the exposing position. The sliding catch Fis
mounted on a piece fixed on the pivot O at the bottom of the camera and is
adapted to pass into notches P in an arc of a circle corresponding with the inner
arc of the radial grooves A. These notches may be numbered consecutively pre-
cisely in the same manner as the entrance to the radial grooves, with the object of
rendering easy the apposition or withdrawal of any particular plate. In order to
hinder the plate falling into the radial grooves as the slide is turned round the top
pivot H is made hollow so as to allow a pin, bearing a milled head, to pass through,
which has attached to it a piece of brass J, or other material bent at right angles
and acted on by a spring K causing it to cover the entrance to groove B. In the
middle of the partition of the slide is an aperture L to allow a spring M, or some
means of pressure to act at the back of the plate with the object of bringing the
plate into what is known in photographic language as register." A continuation
of the pin I slightly bent at its end moves the said spring M simultaneously with
the angular covering J at the end of the slide groove B.
Dated this Third day of April 1890.
GEORGE DICKINSON,
Applicant.
COMPLETE SPECIFICATION.
Improvements in Photographic Cameras.
I, GEORGE DICKINSON, 144 Morley Avenue, Noel Park, London, N., Photo-
graphic Salesman, 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 :-
My invention relates to an improved magazine plate changing camera whereby a
number of plates may be carried within the body of the camera and brought suc-
cessively to position for exposure; and the invention consists essentially in the

page_text: combination, with sets of plate-holding grooves radiating from a common centre, of
a turntable plate holder whose axis is concentric therewith whereby any one of the
plates may be received from the magazine grooves and brought into position for
exposure and returned again to its grooves after exposure, the transfer of the plate
to, or from, the turntable holder being effected by its own gravity.
The invention also comprises accessory means whereby the displacement of the
other plates is prevented when transferring one of them; whereby the plate is held
in proper position in the turntable holder; and the passage of light past the plate
under exposure is prevented.
Reference is to be had to the accompanying drawings, forming part of this Specifi-
cation; wherein
Figure 1 is a horizontal section and Figure 2 a longitudinal vertical section
through the magazine and turntable holder of the camera.
Figure 3 is a cross-section on line 1-1, Figure 1.
Figure 4 is a plan of the index for use in setting the turntable holder in register
with the magazine grooves..
Figure 5 is a cross-section through one of the disc heads of the turntable
holder.
The same letters of reference denote like parts in all the figures.
A is the body of the camera provided with a door B at back by which access is
had to the grooves C C' of the plate magazine. These grooves are formed in the
top and bottom plates D D' of an internal frame, preferably of metal, enclosed
within the body A and they radiate from the circumference of the turntable plate
holder_composed of discs E El connected by a vertical and nearly diametrical
plate E and turning on central vertical pivots e el in plates D D' and body A.
These discs E E' have diametrical grooves which may be made to coincide
with any pair of grooves C C¹ by turning the holder about its vertical axis, the edges
of the discs E El being opposite to, and closing the inner ends of the grooves C C₁
except those to which the grooves fare opposite. The grooves C C and fƒ³
are of such breadth and length as to receive the plates of the size for which the
camera is intended. g is an arm attached to a pivot passing centrally through the
pivote of the turntable plate holder and provided externally with a milled head h
by which to operate it. This arm g is between the disc E of the turntable plate
holder and the frame D and it terminates in a small inwardly turned arm g' passing
through an aperture in said disc alongside the end of the groove f¹ the end of said
arm g being bent horizontally so as to lie across the end of the groove f¹ and close
it in order to prevent the plate slipping out of the grooves of the turntable plate
holder when turning the fatter about its axis to the position for exposure, should
the camera be so held that the axis of the turntable is not vertical. The arm g
drawn into this position by a spring attached to it and to the disc E¹ and is
turned so as to withdraw the stop from the end of the groove f¹ by slightly
turning the milled head h. The plate is prevented from passing out at the other
end of the grooves f¹ by fixed stops. The turntable plate holder is turned
about its axis by an arm I fixed to its other pivot, and terminates in a spring latch i
adapted to engage in a notched quadrant numbered to indicate the different
grooves of the magazine and whereby the holder is held in accurate register_with
any given pair of grooves C C³ for the purpose-of-transferring a plate and is also
held-stationary when turned to the position for exposure. The turntable holder is
represented in this latter position in dotted lines in Figure 2. The edges of the
plate E² then abut against the velvet-faced bevelled lips k k of two inwardly-pro-
jecting transverse partitions K one at either side of the turntable plate holder
whereby the transmission of light beyond the latter is entirely cut off. The plate E³
of the turntable holder carries the usual spring to press at the back of the plate and
hold it accurately in register in the focussing plane and said plate also has a central
aperture closed by a slide L which on being withdrawn admits of a ground glass
being substituted for the purpose of ascertaining the correct focus of the lens for
objects at different known distances which only requires to be done once.
is
The

page_text: focussing motion is operated by an index arm M working over an arc m upon which
the various positions of the lens corresponding to objects at the various known
distances are inscribed, so that the lens may be readily focussed at any time to suit
the distance of the object.
It is to be observed that the plates as used in this camera, require no protective
sheaths as used in other magazine cameras, since the passage of light past the plate
under exposure is entirely prevented.
Having now particularly described and ascertained the nature of the said inven
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In a magazine plate changing camera, the combination of a turntable plate
holder having diametrical plate holding grooves with a magazine having sets of
plate-holding grooves radial to the axis of the turntable holder, with any of which
the grooves of the turntable holder may be made to register, substantially as and
for the purpose specified.
2. The combination, with the turntable holder and radial magazine, as described,
of the indicator for denoting the position of the turntable holder with regard to the
magazine and for fixing it in that, or in the exposing, position, substantially as
specified.
3. The combination, with the turntable holder and radial magazine, as described,
of the axially-operated spring stop for retaining the plate in the turntable when
turning the same, as described.
4. The combination, with the turntable holder, of the abutments for preventing
the passage of light past the plane of exposure, as described.
Dated this 5th day
1001
GEORGE DICKINSON.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
GEORGE DICKINSON.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.