Improvements in Film-carriers and Dark-slides for Photographic Purposes.
Year: 1892

page_text: Date of Application, 31st Mar., 1892-Accepted, 7th May, 1892
COMPLETE SPECIFICATION..
Improvements in Film-carriers and Dark-slides for Photographic
Purposes.
I, BENJAMIN JOSEPH EDWARDS of the Grove, Hackney, in the County of
Middlesex, 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 invention relates to photographic film-carriers and dark-slides, and is intended
to improve the construction and to reduce very considerably the cost, weight and
size of such articles.
My improved carriers and slides are made preferably of thin sheet metal and
comprise the improvements hereinafter set forth.
In the accompanying drawings I have shown how my invention may be conveniently
and advantageously carried into practice.
Figure 1 is a front view,
Figure 2 a rear view, showing a film partially inserted, and
Figure 3 is a top view of one form of my improved film-carrier.
Figure 4 is a front view, and
Figure 5 is a rear view of my improved dark-slide case or frame.
Figure 6 shows the shape of the stamped case or frame before being folded to
the form shown in Figures 4 and 5.
Figure 7 is a front view of the inner slide, the flap hereinafter described being.
shown by full lines in the closed position, and by dotted lines in the open position.
Figure 7 shows the lower end of a slightly modified form of inner slide.
Figure 8 is an edge view of the said inner slide with the flap open.
Figure 9 is a similar view with the flap shut.
Figure 10 is a view of the shutter.
Figure 11 is a rear view of the dark-slide complete.
Figure 12 is an edge view of the slide complete.
Like letters of reference indicate corresponding parts throughout the drawings.
My improved film-carrier consists of a thin sheet metal sheath or frame A having
its sides A¹ turned over to form grooves or guides A2 for the film. I make these
grooves sufficiently wide to allow a piece of cardboard to be inserted with the film.
Both ends of the carrier may be left open for the insertion of the film, or the lower
end may be closed by turning up the metal of which the carrier is made, as shown
at A³.
I make in the metal forming the said sheath or case a large opening B and I
make this opening of such shape that the edges of the same shall not interfere with
or prevent the easy insertion of the film. For instance 1 may make the opening
circular or oval or otherwise suitably curved but I prefer to make it nearly
rectangular except that the lower end is inclined to the sides or V-shaped as shown
in the drawing. By this construction the film can be slid into the frame readily
without being obstructed by the lower edge of the opening B as would be the case
were the said edge made square with the sides of the case. This construction forms
an important feature cf my invention enabling as it does the film to be inserted
readily and properly in the dark, or in the dull light of the photographers dark room.
My improved film-carrier is preferably stamped from a single piece of metal such
as tin plate or aluminium. It is extremely light, the weight being materially
reduced by reason of the opening B which also confers the further advantage that
the carrier can be used very advantageously in an ordinary dark-slide inasmuch as
the opening in the back of the carrier allows the dark-slide spring to press upon the

page_text: back of the cardboard and thus maintain the film in its proper position pressed
close up to the inside of the grooves formed by the turned over sides A¹ of the
carrier.
When I close one end of the carrier to form a stop for the film as shown at A³ I
cut out a small piece of the frame as at A' so that the film can be readily seized by
the finger and thumb when it is required to be withdrawn.
Glass plates can also be used in the same carrier, and these being always when in
use pressed against the inner edges of the groove by means of the dark-slide spring
as aforesaid it is obvious that both films and plates irrespective of their thickness
will always be in register in the camera and will consequently be accurately in
focus with the lens. My improved carriers can also be used for films in place of
the ordinary metal sheath used in some forms of magazine cameras. When required
for this purpose I sometimes form a catch or stop which serves to prevent the plate
or film falling out of the carrier; such catch or stop may be similar to that described
by me with reference to the sheath or carrier shown in my prior Specification of
Letters Patent No. 11416 of 1889. This stop or catch may be conveniently formed
by turning up a small piece of the metal which forms the back of the carrier. The
plate or film during insertion slides over the said raised stop and the latter springs into
position and engages with the edge of the plate when the plate or film is pressed
home in the carrier. To facilitate the withdrawal of the plate or film from the
carriers so constructed I partially cut away a portion of the opposite or closed end
of the carrier so that the plate or film may be easily pushed out of the carrier and
over the raised catch which is temporarily pressed down for that purpose.
The dark-slide constructed according to my invention comprises first a sheath or
carrier C for the film or plate constructed somewhat similar to the film-carrier above
described. It is provided with a light-tight cut off or stop C₁ at the top to prevent
the light reaching the plate or film when it is in position in the dark-slide. This
light-tight stop I make in the form of a hinged flap, of wood, metal or cardboard,
covered with velvet or cloth C2 by means of which covering it is hinged to the end
of the carrier as shown in Figures 7, 8 and 9. The lower edge of the said flap is
formed with a recess C³ so as more perfectly to cover the end of the plate, and,
when films are used, to hold the film down in its place so that it will not obstruct
the insertion of the sliding shutter in the outer case hereinafter described. Some-
times I make the light-tight cut off a fixture and leave the lower end of the carrier
open for the insertion of the plate or film. The ridge C formed by the flap attach-
ment serves for conveniently drawing the inner carrier out of the outer case.
In connection with the sheath or carrier I employ an outer case of thin sheet
metal which I stamp or cut to the required shape from a single piece of metal. The
shape of the flat stamped sheet is shown in Figure 6. This piece of metal is bent
or folded so as to form the frame or case into which the inner sheath or carrier
above described slides. The back of the said frame or case is formed by the
wings D', D' and the portion D2 shown in Figure 6, these parts being turned over
to form the case or frame in the manner shown in Figure 5.
The edges of the wings D', D' overlap each other and are secured together by
clips D³, D³; the said clips are stamped or cut out solid with one of the wings D
and are folded over the other part D to hold both in position. By this improved
method of construction no soldering is required to hold the frame together.
D' D are spring pieces formed solid with the wings D' D'. They are bent some-
what as shown in Figure 12 for the purpose of retaining the inner slide or carrier
in position when it is inserted in the frame. It will be seen that the whole of the
outer frame and springs are formed of one piece of metal. To ensure light-
tightness at the top and bottom of the frame I fix thereto strips of velvet or
cloth E, E' which may be conveniently secured to the inside of the case or frame
by folding or turning up the edges of the metal of which the frame is formed.
like manner I secure the hinged light-tight flap or cut off C¹ to the inner frame or
carrier C.
In

page_text: The opening F in front of the outer case or frame through which the plate or
film is exposed is formed with its lower edge F¹ V-shaped as shown or the said
edge may be inclined to one side of the frame or curved for the purpose of enabling
the film and also the sliding shutter to be properly inserted without risk of being
stopped or obstructed by the said lower edge of the opening.
I form the sliding shutter G which covers the opening of very thin card-board
or other suitable material. It is very important that the frame be so constructed
that the sliding shutter can be pressed properly home so as to completely protect
the plate or film from light when the dark slide is removed from the camera.
With the V-shaped or inclined or curved edges of the lower end of the exposure
aperture a very thin sliding shutter may be safely used without fear of catching
on the lower edge of the opening and so causing the plate or film to be spoiled by
light when the dark slide is removed from the camera. For further protection
I fix on the inside of the sliding shutter and near its lower end a strip of velvet G¹
which rests upon the surface of the plate or film and serves when the shutter is
withdrawn to wipe from the film any dust which may have collected thereon. I
sometimes, especially for the larger sizes of dark-slides, make the outer case D of
sufficient length to allow the shutter to pass beyond the end of the plate or film.
Such a construction is shown in Figure 7 where the lower end of the inner carrier
is made V-shaped. The apex of the V clearly prevents the film being pressed to the
very bottom of the outer case and therefore the shutter will pass sufficiently far over
the end of the film to prevent any risk of light entering thereunder. The stop C³ at
the lower end of the inner carrier being flush with the face of the carrier, and of a
V-shape as shown in Figure 7 the sliding shutter will pass freely over the said stop
and between it and the outer case or frame. The said stop C5 serves as a support for
the shutter and prevents the latter being pressed inwards. This construction affords
the further advantage that it is not necessary to cut to waste any material portion of
the film. I provide the shutter with a tab G' to facilitate its withdrawal. This
tab can be made to serve as an indicator to show when the plate has been exposed,
by turning it down when the shutter is replaced after the exposure of the plate.
This is provided for in the construction of the dark-slide which allows for the
insertion of the tab between the sliding shutter and the outer case.
My improved dark-slide is exceedingly light and cheap to make and being very
thin it occupies much less room than does any dark-slide for the same size of film
heretofore in use. It is moreover very strong and more durable than dark-slides
of the ordinary construction.
It is obvious that I can make my dark-slide of any suitable metal or material
and when a specially light dark-slide is required I make it of aluminium for which
it is by its construction specially adapted, there being no soldered joints and
aluminium being a metal which cannot easily be soldered or welded.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is :-
First. A film-carrier composed of a single piece of sheet metal having an opening
in the back, the said opening being inclined to the side at its lower edge, or curved,
so as not to obstruct the insertion of the film, substantially as described.
Second. A dark-slide having a case or frame composed of one single piece of
thin sheet metal, substantially as described.
Third. The dark-slide case or frame formed of one piece of sheet metal, and
having an exposure opening one edge of which is inclined, or curved, or V-shaped,
substantially as described, and for the purpose specified.
Fourth. The inner slide or carrier with a light-tight flap or stop, constructed
substantially as described.
Fifth. The shutter in combination with the dust-wiping strip, substantially as
described,

page_text: Sixth. The dark-slide comprising the frame, the slide and the shutter, constructed
substantially as described and shown in the drawings.
Dated this 31st day of March 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.