Improvements in Dark Slides for Photograph Cameras.
Year: 1896

page_text: Date of Application, 4th Feb., 1896
Complete Specification Left, 18th May, 1896-Accepted, 27th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in Dark Slides for Photograph Cameras.
I, EDWARD POCKNELL of 45, Powderham Crescent, Exeter, retired Journalist,
do hereby declare the nature of this invention to be as follows:--
This invention relates to improvements in connection with. dark slides for
photographic cameras, and is intended to provide means by which these slides can
be more conveniently employed, and by which all danger of injury to the plates by
light is obviated.
According to one. portion of my invention I employ an improved shutter in
which the main portion of the shutter can be detached leaving the bottom part
permanently connected to the slide.
For this purpose a pull off hinge or connection is used so that the shutter can be
pulled to the top of the slide and then at once detached. The shutter and bottom
ledge slide in grooves in the usual manner, the bottom ledge being prevented from
moving past the upper end of the slide. This ledge covers the top of the glass
and prevents any danger of light leaking through this part, and thus injuring the
plate at the other side.
The connection I propose to employ between the shutter and the ledge consists
of a small hook on the latter and a corresponding hook on the bottom of the
shutter so placed that the two can engage together when the shutter is in line
with the ledge. The shutter and ledge are rebated and the lower end of the
shutter is formed with a recess in its inner face into which the hook on the ledge
can extend to engage with the upper hook. Thus on pulling the shutter to the top
it can be at once detached by a slight motion to one side.
This arrangement is especially convenient in the case of hand cameras as it
allows the shutter to be completely removed instead of having it lying on top of
the camera or otherwise placed in an inconvenient position.
Another portion of my invention consists of a simple indicating device fitted to
the top of the slide. This indicator is made from a small metal bar or strip
furnished with a head and sliding in a groove. The indicator can be moved to
either end of the groove and according to its position it will indicate whether the
plate has or has not been used.
To open the slide for insertion or removal of the plates, I employ a small door
of metal or other suitable material hinged to one of the lower corners of the slide
and extending across the bottom, a groove being formed to receive it.
The door is furnished with a small hinged plate serving as a catch, a pin being
fitted to the side of the slide to retain the plate. The door is furnished with two
narrow ribs or ledges which project into the ends of the compartments carrying the
plates supporting the latter and holding them in position.
To remove the plates the door is opened allowing them to fall into the hand.
Dated this 4th day of January 1896
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.

page_text: I, EDWARD POCKNELL, of 45 Powderham Crescent, Exeter, retired Journalist,
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 improvements in connection with dark slides for
photographic cameras and is intended to provide means by which these slides can
be more conveniently employed, and by which all danger of injury to the plates
by light is obviated."
According to my invention I employ an improved shutter in which the main
portion of the shutter can be detached leaving the bottom part permanently
connected to the slide.
For this purpose a pull off hinge or connection is used so that the shutter can be
pulled to the top of the slide and then at once detached.
The shutter and bottom ledge slide in grooves in the usual manner the bottom
ledge being prevented from moving past the upper end of the slide. This ledge
covers the top of the glass or sensitive plate and prevents any danger of light
leaking through this part and thus injuring the plate.
The connection I propose to employ between the shutter and the ledge consists
of a small hook on the latter and a corresponding hook on the bottom of the
shutter so placed that the two can engage together when the shutter is in line with
the ledge.
The shutter and ledge are rebated and the lower end of the shutter is formed
with a recess in its inner face into which the hook on the ledge can extend to
engage with the upper hook. Thus on pulling the shutter to the top it can be at
once detached by a slight motion to one side.
This arrangement is especially convenient in the case of hand cameras as it
allows the shutter to be completely removed instead of having it lying on top of
the camera or otherwise placed in an inconvenient position.
To open the slide for insertion or removal of the plates I employ a small door
of metal or other suitable material hinged to one of the lower corners of the
slide and extending across the bottom a groove being formed to receive it.
The door is furnished with a small hinged plate serving as a catch, a pin being
fitted to the side of the slide to retain the plate. The door is furnished with two
narrow ribs or ledges which project into the ends of the compartments carrying the
plates supporting the latter and holding them in position.
To remove the plates the door is opened allowing them to fall into the hand.
To enable my invention to be better understood I will proceed to describe the
same by means of the accompanying drawing in which:-
Fig. 1, shews a front elevation of a double dark slide fitted with one form of my
improvements.
Fig. 2, is a side elevation of same, part being in section.
Fig. 3, is a front elevation of part of a shutter attached to the ledge by a
hook.
Fig. 4, is a vertical sectional view to enlarged scale of ledge and grooves, the
upper part of shutter being detached.
Fig. 5, is a front elevation shewing modification of hinge connection.
Fig. 6, is a sectional view to enlarged scale of pull off hinge or connection shewn
in Figs. 1, 2.
Fig. 7, is a perspective view of lower part of the slide shewing one method of
inserting plates.

page_text: Fig. 8, is a vertical section of a slide hinged at the end and fitted with detachable
shutter.
In the drawings 1, is the frame work of a double dark slide which may be made
of wood metal or other suitable material; 2, are the grooves in which the tongues 21
of the moving shutter 3, slide. 2 the grooves in which the sensitized plates 3
are inserted; 4, is the diaphragm inserted between the plates 31.
In Fig. 1, the main or detachable portion of one of the shutters 3, is shewn
partly withdrawn from the ledge 6, which is retained in the upper part of the
slide and prevents the entrance of light to the plate during exposure. The main.
or detachable part of the shutter is connected to the ledge by means of a divided
or pull off hinge, which when referred to as a whole is indicated by the number 7,
see also enlarged view Fig. 6. This type of hinge may be conveniently formed of
two pieces of thin metal such as brass bent up, cast or otherwise formed in the
shape shewn. The part A, which is preferably mounted upon or recessed into the
detachable portion of the shutter 3, sliding firmly within the part B, mounted upon
or recessed into the ledge 6. The hinge 7, thus formed when the respective parts
are brought together extending the full width of the shutter as see Fig. 1, thus.
producing a flexible detachable and perfectly light tight joint. The ledge 6, is
prevented from being pulled out of the slide when the shutter is drawn up to
expose the plate by means of an angular piece of metal 8, see also Fig. 4, mounted
upon its lower part and overlapping the same inwardly so as to engage with a
rebate 8' formed in the upper part of the frame of slide, the inner face of the angle
piece 8, as well as the upper part of the frame may be coated with thin leather,
felt or the like 9, to ensure the more perfect exclusion of light.
A ring 11, may be sunk within the top of the slide if desired for the purpose of
withdrawing the same from the camera.
In Fig. 3, I have shewn a hook connection between the detachable part of the
shutter 3, and ledge 6, the respective parts being held together by means of a
hook 10, sunk or recessed into the ledge 6, and a similar hook 10¹ mounted in a
recess 10" formed in the material of which the slide is constructed.
Fig. 5, shews another form of hinge connection 7' recessed so as to be flush with
the material of the shutter and mounted upon the respective parts of the shutter
and ledge.
By pulling the main part 3, in the direction of the arrow the upper part of
hinge 7 is withdrawn from the hinge pins 7 shewn in dotted lines, and thus
released from the ledge 6.
I have shewn in Fig. 7, a form of door for the insertion and withdrawal of the
plates in dark slides of the type frequently employed for hand cameras in which
there is no hinged joint 17, at the end as shewn in Fig. 8. The door shewn
consists preferably of a piece of metal 12, hinged to one of the lower corners of
the slide and extending across the bottom, a groove 13 being formed to receive it.
The door may be furnished with a hinged plate 14, serving as a catch, a pia 15,
being fitted to the side of the slide to retain it, the door is provided with
two narrow ribs or ledges 16, which project into the ends of the compartments
carrying the plates 3', supporting them and holding them in position. To remove
the plates this door is opened allowing them to fall into the hand or otherwise.
Although I have described this form of door as a convenient means for inserting
and withdrawing plates from slides of this type I lay no claim to the particular
construction described and shewn nor do I confine the application of my invention
to single or double dark slides of this class; they may for instance be fitted to
single or double slides hinged at the end as see Fig. 8 opening as shewn or in any
other well known manner.
Single or double detachable shutters divided by means of a pull off hinge or
equivalent connection in accordance with my invention may also be fitted to and
used with any suitable type of camera. In the case of a hand camera my invention
permits the upper part of the shutter to be completely removed and avoids the
inconvenience arising from its lying upon the top of the box or bellows and thus

page_text: interfering with the line of sight, and for instruments mounted upon a tripod or
other stand its removal enables the cloth used for focussing to lie evenly and
renders the instrument steadier in windy weather, besides in both cases making it
more compact and convenient for handling. The operation of detaching the main
portion of the shutter from the ledge 6, left in the slide is practically the. same in
each of the modifications described; after drawing the main portion 3, to the
top of the groove a slight pull sideways is sufficient to disengage it from the
ledge 6.
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. In a dark slide for photographic cameras the combination and use of a sliding
shutter, divided transversely and fitted with a pull off hinge or connection which
enables the main or upper portion of said sliding shutter to be detached from the
lower part left in the dark slide, by the means for the purpose and in the way
and manner described.
2. In a single or double dark slide for use with photographic cameras, the
combination and use with a moving shutter divided as described in Claim 1, of a
pull off hinge or hook connection the co-operating parts of which are mounted
respectively upon or recessed into the upper detachable part and the ledge left in
the slide for the purpose and in the manner described.
Dated this 18th day of May 1896.
FRANCIS M. ROGERS,
Agent for Applicant.