Improvements in Photographic Cameras.
Year: 1890

page_text: Date of Application, 20th Aug., 1890
Complete Specification Left, 19th May, 1891-Accepted, 27th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Photographic Cameras.
I LOUIS AUBREY FRANKS of 95 and 97 Deansgate Manchester in the County
of Lancaster Optician do hereby declare the nature of this invention to be as
follows:-
This invention relates principally to that class of portable camera known as
"detectives" and consists of a simple arrangement of mechanism for giving either
an instantaneous or a "time" exposure.
The shutter which opens or closes the lens aperture is made of a plate of metal
in the form of a lever with an elongated head.
This head is provided with a blank part at each end for covering the lens aperture,
and a central opening for the exposure, and it works in a slot in a metallic guide
attached to the front of the camera close to the lens opening so as to keep it steady
and light tight.
The lever works upon a central screw and its tail end is provided with a spring
which has a constant tendency to draw the shutter over the lens aperture.
To the side of the camera, near the front edge thereof I fix a catch made of
a piece of spring wire, bent so as to form two catches which just project beyond
the front edge.
For a "time" exposure the tail end of the shutter is drawn down until it is held
by the top catch which opens the lens to the full aperture and after the plate has
been exposed long enough the catch is drawn back and the spring causes the shutter
to be closed by the upper blank.
For an instantaneous exposure the tail end of the shutter is drawn down until
it is held by the lower catch which causes the lower blank to close the
opening.
On drawing back the catch the central opening is flashed past the lens aperture
and the instantaneous exposure thus given.
Dated this 19th day of August 1890.
GEO. DAVIES & SONS,
4, St. Ann's Square, Manchester, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Photographic Cameras.
I, LOUIS AUBREY FRANKS of 95 and 97 Deansgate Manchester in the County
of Lancaster Optician 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 improvements which are the subject of this invention relate to the means
employed for operating a shutter in a photographic camera, in order to obtain either
instantaneous or time exposure.
I attain this object by mechanism hereinafter described and as illustrated in the
accompanying sheet of drawings, in which
Fig. 1 is a view of front of camera and Fig. 2 plan of the same; in both of these
views the shutter is represented as closed and covering the aperture for lens.
Fig. 3 is also a view of the front of camera and Fig. 4 plan of the same but with
shutter represented in position hereinafter described.
Similar letters refer to similar parts throughout the several views.

page_text: At one side which may be either the inner or outer side of the front a of a photo-
graphic camera b, I place a T shaped shutter. d; I pivot and secure this shutter to
the camera front a by means of a pin, or stud C; I form an aperture or opening d¹
in the head of aforesaid shutter, said opening being a little larger than the aperture g
for lens; the remaining portion or ends and a³ of head of shutter are: :left blank
and are each of a sufficient size to cover the aperture for lens; to the tail end d
of shutter d, I attach a stud e which I connect by means of a spring or an elastic
band e' or a spiral spring to a stud e² in camera front. I place a spring catch on
side of and near the front of camera for the purpose of retaining the hereinbefore
described shutter d either in a fully or partly open position.
In order to obtain instantaneous exposure, I press back the tail end d' of shutter d
until the said end is outside the end of the catch and is held by said catch,
when the shutter will occupy the position represented by dotted lines in Fig. 3.
The end 2 of shutter will thus cover the lens aperture g.
When admission of light is required for the purpose of taking a picture, the spring
catch fis drawn or pressed back by the handle when by means of the spring, e
the shutter is caused to be closed with the end d³ covering lens aperture g as shown
in Fig. 1 light having been admitted through the opening d' while passing in front
of the lens aperture g.
The head d of shutter is kept close to end board of camera by the guides .h
and h¹.
When an interval of time is required for exposure the tail d of shutter is stopped
midway by the centre part 2 of catch ' causing the aperture g to remain uncovered
as long as desired, when the tail end may be again released and the shutter
entirely closed.
'
Having now particularly described and ascertained the nature of this my said
invention and in what manner the same is to be performed I declare that what I
claim is
In a photographic camera for the purpose of obtaining either instantaneous or
prolonged exposure, the use of a shutter of a T or other like form, which is operated
in the manner substantially as hereinbefore described.
Dated this 18th day of May 1891.
LOUIS AUBREY FRANKS,
Applicant.