Improvements in and in connection with Photographic Dark Slides or Changing Backs.
Year: 1893

page_text: Date of Application, 22nd Apr., 1893
Complete Specification Left, 9th Sept., 1893-Accepted, 14th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in and in connection with Photographic Dark Slides
or Changing Backs.
JOSEPH GEORGE REID Woodlee Cottage, Bloomfield, Belfast Ireland House
Laud and Estate Agent do hereby declare the nature of this invention to be as
follows:-
A box used as a dark slide made of wood or other substance to hold any
number of plates, in carriers made of sheet zinc or other substance. The box is
fitted in front with sliding light-tight double-back shutter, to which is affixed a
spring pin which acts on an indicator inserted in frame work of box. The
indicator is for showing the number of the plate in position for exposure and
consists of a barrell axle round which are affixed or engraved numbers on cog
wheel the pin affixed to the shutter causes the wheel to revolve on the shutter being
closed, the wheel has cogs or teeth according to the number of plates the box is
made to hold. The back is detachable for the purpose of filling the box with
plates and is light-tight being fitted into grooves and held in position by clasps.
Affixed to the back on the inside are springs which press on the backs of the
carriers so that when the shutter is withdrawn for exposure of plate, a plate by
the action of the springs comes into the position which the shutter occupied. At
one side of the box is affixed an opaque bag made of cloth or other substance, and
in the side of the box to which the bag is affixed there are two slits one being to
allow the plate which has been exposed to pass into the bag, this is done by the
closing of the shutter, a plate having by the action of the springs been forced into
its place, on being closed the shutter drives the plate forward through the slit into
the bag. The second slit is for the purpose of passing the exposed plate from the
bag back again into the box and is so arranged that the plate comes in at the back
of the box in a position between the springs and the last plate, thus ensuring the
full pressure of the springs aud the safety of the plates, the bag is collapsable and
can be folded over the box.
JOSEPH G. REID.
F
COMPLETE SPECIFICATION.
Hvements in and in connection with Photographic Dark Slides
or Changing Backs.
I JOSEPH GEORGE REID of Woodlee Cottage Bloomfield, Belfast in the
County of Antrim Ireland do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
-
This invention consists of a box or frame to be used as a dark slide for
photographic purposes as is well understood so constructed of wood or suitable
material as to hold a number of plates in carriers made as hereafter described and
illustrated of sheet zinc or other desirable substance and in such manner as to
cause the front plate after exposure to be displaced automatically by the replace-
ment of shutter, dropped into a dark receptacle and then replaced by hand at the
rear of the box or slide without danger of exposure to the light.
In describing my said invention I shall refer to the accompanying sheet of
drawings on which
Figure 1. is a horizontal section of my dark slide
Fire a plan and

page_text: Figure 3. an elevation of same
Figure 4. being a view of the double back shutter showing folding joint or
flexible hinge and other details.
This double
The box or slide a is fitted in the front with a sliding light-tight double back
shutter b. having grooved and tongued edges formed to fit in corresponding grooves
in the box a. one of the functions of the said shutter being to displace the plate
after exposure into a bag e hereafter described and for this purpose it is shod on
the back edge with a strip of metal c (or other hard material) to engage with the
carrier d. when pushing said carrier with its plate into the bag e.
back shutter b. is provided with a spring pin or pawl i. engaging with the
indicating ratchet wheel . which is placed in the frame for the purpose of
shewing the number of the plate that is in position for exposure, being mounted on
a barrel axle (not shewn on drawings) round which numbers are marked the axle
being rotated by ratchet wheel l. actuated by pin i. on the shutter b. the wheel l.
having teeth corresponding in number to the number of plates to be contained in
the dark slide.
n, n, are grooves on the shutter 6 for the purpose of acting as guides and also
for excluding light, and said shutter is provided with a flexible hinge p (with a
light tight tongue) and groove joint at q.
The back of the box or dark slide is detachable so as to enable the plates to be
placed in position and is made light-tight being fitted in grooves and held in
position by clasps o. and is also supplied with springs h. on its internal face for the
purpose of pressing against the rear plate and keeping the whole in position. At
one side of the box or dark slide is an opaque bag e. and in the side of the box to
which the bag is affixed are two slits fand g. one of these fallows the plate after
exposure to be pushed by the action of the shutter into the bag and the other
slit g permits of the said plate being returned through same from the bag to the
rear of the box or dark slide, it then occupying a position between the springs h.
and the former last plate so ensuring the full pressure of the springs and the
consequent safety of the plates. I may vary these details to suit different sizes
and styles of apparatus without departing from the spirit of my invention.
The action of the apparatus is as follows. The dark slide or box being filled
with carriers and their plates and the said dark slide placed in the camera ready
for exposure the shutter is withdrawn and the exposure effected. On the shutter
being closed the plate just exposed, which has now been pushed by the action of
the back springs h. to the front and has occupied the space formerly filled by the
shutter, is forced by the return of the shutter into the bag, and is replaced through
slit g in the rear of the dark slide and between spring h. and the former rear plate
& carrier.
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
1st. In photographic apparatus the use of a dark slide or changing back
constructed and arranged substantially as hereinbefore described and with reference
to the accompanying sheet of drawings.
2nd. In dark slides or changing backs used in photographic apparatus the
combination of a box or frame such as a provided with a-dark bag such as e. with
a detachable back such as before described having attached thereto springs such
as h. and a double back shutter such as b. provided with a shoe or strip such as c.
for the purpose of pushing out a plate after exposure substantially as hereinbefore
described and as illustrated by accompanying drawing.
POPPLEWELL & Co.,
Agents for the Applicant.