Improvements in or relating to the Dark-slides of Photographic Cameras.
Year: 1892

page_text: Date of Application, 24th Mar., 1892
Complete Specification Left, 24th Jan., 1893-Accepted, 4th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Dark-slides of Photographic
Cameras.
I, ANTHONY HOGARTH KIRBY, of 20, Cornwall Terrace, Manningham Lane,
Bradford, in the County of York, Cabinet-maker, do hereby declare the nature of
this invention to be as follows:-
This invention relates to the dark-slides or receptacles for containing plates or
films sensitive to light to be exposed in photographic cameras, and has for its
object to provide a means or stop for preventing the sliding shutters of such dark-
slides from being pulled out too far when exposing a plate or film to light.
According to my invention I cut out of sheet metal, preferably brass, two
☐ shaped or similarly shaped springs for each of the sliding shutters of the dark-
slide. These shaped springs are countersunk into the substance forming the
inner lower portion of the sliding shutters, one on either side of same, and such
springs are made fast, at their bases, by means of screws, for instance, to the said
sliding shutters so as to slide up and down between the grooves in the framework
of the dark-slide. A small portion of the framework inside the top part of the
grooves is cut away in such a manner that, when the sliding shutters are drawn out
the full distance to effect the exposure, the springs shall take into such cut away
parts and so prevent the shutters from being further withdrawn but yet allow of
their being easily slidden back after the exposure.
Dated this 23rd day of March 1892.
CROSSLEY & Co.,
72, New Market Street, Bradford, Yorks., Agents.
COMPLETE SPECIFICATION.
Improvements in or relating to the Dark-slides of Photographic
Cameras.
I, ANTHONY HOGARTH KIRBY, of 20, Cornwall Terrace, Manningham Lane,
Bradford, in the County of York, Cabinet-maker, 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 the dark-slides or receptacles for containing plates or
films sensitive to light to be exposed in photographic cameras, and has for its object
to provide a means or stop for preventing the sliding shutters of such dark-slides
from being pulled out too far when exposing a plate or film to light.
According to my invention I cut out of sheet metal, preferably brass, two
L shaped or similarly shaped springs for each of the sliding shutters of the dark-
slide. These L shaped springs are countersunk into the substance forming the
inner lower portion of the sliding shutters, one on either side of same, and such
springs are made fast, at their bases, by means of screws, for instance, to the said
sliding shutters so as to slide up and down between the grooves in the framework
of the dark-slide. A small portion of the framework inside the top part of the
grooves is cut away in such a manner that, when the sliding shutters are drawn
out the full distance to effect the exposure, the L springs shall take into such cut
away parts and so prevent the shutters from being further withdrawn but yet
allow of their being easily slidden back after the exposure.

page_text: In order to allow of the invention being better understood I will now make
reference to the accompanying drawings.
Fig. 1 represents a photographic camera double dark-slide, in front elevation,
partly broken away, with my invention applied thereto, the front shutter being
partly drawn out, and
Fig. 2 is a side sectional elevation on the line a, b.
A is the front and A¹ the back sliding shutters and B the framework, all as
usual or well known. C represents the metal springs, which may be of the form
shown or any other suitable shape, and c denotes the screws by which such springs
are attached to the shutters. indicates the cut-away portions of the framework
for the springs C to take into when the shutters A or A¹ are drawn out to their
full height.
My invention provides an efficient stop without materially adding to the cost of
the dark-slides, the device not coming into contact with the plates or films and
thus avoiding scratching.
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
clain is :-
The improvements in or relating to the dark-slides of photographic cameras
comprising the construction and application of the devices or stops for the sliding
shutters of same as specified and substantially as described with reference to and
shown on the drawings.
Dated this 24th day of Decemb-1000
CROSSLEY & Co.,
1, Queensgate, Bradford, Yorks., Agents.