Improvements in Photographic Dark Slides.
Year: 1892

page_text: Date of Application, 24th Feb., 1892
Complete Specification Left, 7th June, 1892-Accepted, 9th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Photographic Dark Slides.
I, WILLIAM MIDDLEMISS Alice Street Bradford Scientific Apparatus Manu-
facturer do hereby declare the nature of this invention to be as follows:-
My invention relates more especially to solid slides, and is intended to take the
place of the small buttons or other fastners usually used to keep the sensitive
plates in position. At one end of the slide, on one or both sides, I fix a plate of
brass or other metal. This plate is pivoted at one end, and the other. end is made
to move about inch. When it is required to fill the slide with the sensitive, plates,
this brass plate is moved back, and the plates dropped in-then the brass plate,
(having a spring behind it), moves forward; and projects slightly over the sensitive
plate, and keeps it in its place.
One end of this plate is made to project through the side of the slide, so that it
may easily be moved from the outside.
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1
1000
WILLIAM MIDDLEMISS.
COMPLETE SPECIFICATION.
Improvements in Photographic Dark Slides.
I, WILLIAM MIDDLEMISS, of Alice Street, Bradford, in the County of York,
Scientific 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 invention relates to the class of photographic dark slides known as "solid
slides" and has for its object, the construction of the same in such a manner that, I
am enabled to dispense with the use of the small buttons and other fasteners,
usually employed for securing the sensitive plates within the slide; and to so secure
the said plates that, there is less liability of the films getting damaged when
changing the plates, than is the case when secured in the manner as hitherto.
In describing my invention in detail, reference is made to the accompanying
drawings in which
-
Fig. 1 represents a view of a dark slide made according to my invention, and
in which one shutter is entirely removed and a portion of the frame cut away in
order to more clearly illustrate the construction.
Fig. 2 is a longitudinal section of the same.
Fig. 3 a view of the opposite side of the slide in which one shutter is also
removed, and
Fig. 4 is a transverse section through line a. b.
The frame of the dark slide is indicated by the letter A. and the sliding
shutters by B. these shutters slide in grooves and are retained by the springs C.
as usual.
To one side of the cross piece D. within the dark slide may be secured a thin
plate E. and to the other side of the said cross piece, the hinged plate F. is pivoted,
at one end by a pin G. the other end at F¹ projecting a short distance through a
slot hole formed in the slide; a flange is formed at F2 inside the slide, thus covering
the slot hole for preventing light passing into the interior.
On placing sensitive plates within the slide, the shutter is drawn until the space
between H. and H. is clear, then the hinged plate F. is forced back in the direction
of arrow on applying pressure to the end at F¹ the plate, on insertion, rests in
D
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groove and upon the thin plate E. a piece of zinc or other thin opaque material
is then inserted, followed by the top sensitised plate, the whole being secured in
the slide, on releasing the hinged plate F. which is moved into the position shown
by means of spring S.
In order to prevent the sensitive plates moving endwise, I place a spring J. in
the groove at end of slide, which presses the plates against the interior edge of
cross piece D. thus by these means, the plates are firmly secured in the required
position without the aid of buttons and the like.
- In the case of dark slides having a fixed sheet of zinc or other opaque material in
the centre between the sensitised plates, the thin plate E. is dispensed with, and a
hinged plate F. substituted, thus fitting one to each side of the cross piece D. plates
are inserted, on drawing each shutter and retained by the respective hinged
plates F.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is :-
1. A solid dark slide combined with one or more hinged plates F. arranged and
operated substantially in the manner as shown and as hereinbefore set forth.
2. A solid dark slide combined with a thin plate E. and a hinged plate F.
arranged and operated substantially in the manner as shown and as hereinbefore
set forth.
3. The combination of the parts forming the complete solid dark slide arranged
substantially as and for the purpose hereinbefore set forth and illustrated by the
accompanying drawings.
Dated this 31st day of May 1892.
JOHN WAUGH,
Agent.