An Improvement in Detective or other Cameras.
Year: 1889

page_text: Date of Application, 9th Mar., 1889
Complete Specification Left, 2nd Dec., 1889-Accepted, 25th Jan., 1890
PROVISIONAL SPECIFICATION.
An Improvement in Detective or other Cameras.
FRANK MIALL Photographic Apparatus Maker 13 Shelgate Road Northcote Road
Battersea Rise Surrey, do hereby declare the nature of this invention to be as
follows:-
:-
My improvement in Detective or other Cameras consists of the use of two grooved
boxes superposed on each other with parallel racks on the sides or ends of each box
the said racks to be actuated by a pinion at right angles to and between them having
on its end either a square (to be used with a key) or a milled head on turning which
the one box containing the unexposed plates or films (each in a suitable carrier)
advances as the other receeds and drops a plate or film from the upper box into the
lower one through a fixed slot thus always ensuring each plate or film to be exposed
in a fixed plane to the lens. The said grooved boxes to slide in or on suitable
grooves or runners formed in or on an outer case or box, in the front of which said
box and oscillating at will is a segment of a circle (of metal or other suitable
material) either in a vertical or horizontal position and forming the exposing
shutter, the said segment having an opening for the light to pass through the lens
to the sensitive plate or film the outer ends of the said segment to be opaque so
that before and after exposure the lens will be covered. On the centre of the
segment from which the radius is struck is fixed a pinion which engages in an
oscillating rack, which can be actuated from any part of the camera either by hand
or pnumatic influence.
The camera takes the form of a box of such varied shape as may be found most
convenient and can be covered with paper or other material to suit the individual
tastes of the users and either carried by a strap or handle or the like.
Tinted this 9th day of March 1889
FRANK MIALL.
COMPLETE SPECIFICATION.
An Improvement in Detective or other Cameras.
I, FRANK MIALL 13 Shelgate Road Battersea Rise Surrey, Photographic Apparatus
Manufacturer 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 improvement in Detective or other cameras consists in the use of two grooved
boxes superposed on each other with parallel racks on the sides or ends of each
box the said racks to be actuated by a pinion at right angles to and between them
having on its end either a square to be used with a key, or a milled head on turning
which the one box containing the unexposed plates or films (each in a suitable
carrier) advances as the other receedes, and drops a plate or film from the upper box
into the lower one through a fixed slot thus always ensuring each plate or film to
be exposed in a fixed plane to the lens, the said grooved boxes to slide in or on
suitable runners or grooves formed in or on an outer case or box, in the front of
which said case or box and oscillating at will is a segment of a circle, of metal or
other suitable material in a vertical position and forming the exposing shutter the
said segment having an opening for the light to pass through the lens to the
sensitive plate or film. The outer ends of the said segment to be opaque so that
before and after exposure the lens will be covered. On the centre of the segment
from which the radius is struck is fixed a pinion which engages in a rack which
can be actuated from the side of the camera by hand. The camera takes the form

page_text: of a box of such varied shape as may be found most convenient and can be covered
with paper or other material to suit the individual tastes of the users, and either
carried by a strap, or handle, or 'the like..
My Invention can be more particularly ascertained by reference to the accom-
panying drawings. Fig. 1. A being the upper grooved box (with the racks C. C on
the sides) for containing the unexposed plates or films. Fig. 2. B. being the lower
grooved box (with the racks. D D on the sides) and receives and holds the plates
or films during and after exposure.
Fig. 3 is an end elevation showing the two grooved boxes, A and B in position in
the outer case I. I. I. I. supported by the runners E E and e. e. e. e and having the
pinion F between the racks C. C. and D. D. at a right angle to the grooved boxes A
and B. and G is the milled head for turning the pinion.
Fig. 4 shows the suitable form of runners E. E.
Fig. 5. shows a front elevation of the exposing shutter in which J. is the segment
of a circle M being the cut away portion to allow the light to pass through the
lens N. Lis the pinion on the centre from which the radius of the segment is
struck and K. k. the racks which engage in the said pinion and which racks on being
pushed from the outside of the case by hand at K. K alternately cause the segment
to oscillate.
Fig. 6. is a section of the same shutter, the like letters applying to each and
every drawing.
In Fig. 3. one of the plates or films is shown by H passing from the upper
grooved box A into the lower grooved box B through a slot cut in the runners E: E.
which slot is at that distance from the lens N. which is found to give the sharpest
image on the sensitive plate or film.
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 :-
(1) The use of two grooved boxes superposed on each other and actuated by racks
and pinion substantially as described so that the boxes move simultaneously in
opposite directions.
(2) The use of a segment of a circle having an opening in the centre and with
opaque ends actuated substantially as described and forming an exposing shutter.
Dated this 2nd day of December A.D. 1889,
FRANK MIALL.