Improved Apparatus for Automatically Registering the Exposure of Photographic Plates and Films.
Year: 1894

page_text: Date of Application, 10th Sept.. 1894
Complete Specification Left, 15th July, 1895-Accepted, 18th Sept., 1895
PROVISIONAL SPECIFICATION.
Improved Apparatus for Automatically Registering the Exposure of
Photographic Plates and Films.
We, JAMES RANDOLPH COURTENAY GALE M.A. of 3, Egmont Road,
Sutton, Surrey, and JAMES WILLIAM THOMAS CADETT of Ashtead, Surrey,
Photographic Chemist do hereby declare the nature of this invention to be as
follows:-
This invention has for its object Firstly. To automatically register the
exposure of the plate or plates, or film or films, contained in a photographic dark
slide by means of a suitable indicator; and Secondly. To ensure the automatic
return of such indicator to its original position upon opening such slide. To effect
this we mount upon the slide in any convenient manner and position, a face plate
having a suitable index therein or thereon. Pivotted thereto is an indicator,
which on withdrawing the shutter of the dark slide and exposing the plate or film,
is brought opposite the index, thus registering such exposure. A suitable catch
retains the indicator in this position until the dark slide is opened, when the catch
is released and the indicator either by gravity, or by mechanical pressure, or
otherwise, automatically returns to its original position in readiness to register the
next exposure. The travel of the indicator is regulated by a suitable stop or stops.
In the case of a double dark slide each slide is furnished with an exposure
indicator. If desired the face plate may be dispensed with and the index
mechanism may be mounted directly on the dark slide in any convenient manner
and position.
Dated this 10th
1
100
ELT & Co.,
33 Southampton Buildings, London, W.C., Agents for Applicants.
Improved Apparatus for Automatically Registering the Exposure of
Photographic Plates and Films.
We JAMES RANDOLPH COURTENAY GALE, M.A. of 3, Egmont Road,
Sutton, Surrey, and JAMES WILLIAM THOMAS CADETT of Ashtead, Surrey,
Photographic Chemist 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 improved apparatus for automatically recording the
exposure of photographic plates and films, and has for its object to produce an
apparatus which automatically resets itself, after having recorded the exposure of
a photographic plate or film. This we effect by the mechanism illustrated in the
accompanying drawings,
Figures 1 and 2 whereof shew views in front and back elevation ;-Figure 3 a
side elevation; and Figure 4 a transverse section taken on the line C. D.
Figure 1,-of our improved apparatus.

page_text: Figures 5, 6, 7, 8 and 9 shew modifications of our invention which are hereafter
particularly described.
Similar letters of reference indicate corresponding parts throughout the several
views.
a indicates a portion of a photographic dark slide whereon is mounted a face
plate b having an index aperture 6¹ therein. Pivoted to the back of such plate is
an indicator c having a shoulder c and perforation c². The action of such indicator
is controlled by a hair spring d which is mounted on the plate b. A spring e
furnished with a catch e¹ is likewise mounted on such plate b. This spring is
depressed when the slide is closed by a loose pin f inserted in any convenient
position in the slide a as shewn in Figure 4;-or such pin may be fixed or pivoted
to the spring e or to the frame of the slide. A recess g, Figure 1 is made in the
slide a into which the shoulder c¹ on the indicator c fits when the latter is mounted
on the slide. The operation of our invention as shewn in Figures 1 to 4 both
inclusive is as follows:-Upon drawing out the shutter a¹ of the slide a to expose a
plate or film the shoulder c of the indicator c is lifted out of the recess g, and rides
over the edge of the rebate a² formed on the edge of the shutter a' thus raising the
indicator c and bringing it opposite the index aperture in the plate b to shew
that the plate or film has been exposed in which position it is retained by the
catch e' on the spring e engaging in the perforation c³ in the indicator c.
Úpon
closing the shutter al after exposing the plate or film and opening the slide in
order to remove the latter, the shoulder c¹ of the indicator c falls back automatically
into the recess g owing to the pressure of the pin on the spring e being removed
by the act of opening the slide, thus allowing the hair spring d to come into play
and depress the indicator thereby automatically resetting it in readiness to indicate
the next exposure. In the case of a double dark slide each slide is furnished with
our improved indicating apparatus.
Figures 5 and 6 shew a modified arrangement of our invention whereby the face
plate b is dispensed with, the mechanism being mounted on the hinge plate of one
of the clips of a dark slide.
Figure 5 is a plan of the underside of such clip and Figure 6 a detail view of the
hinge plate thereof shewing the index aperture 6' therein, such hinge plate being
the equivalent of the face plate b. In this arrangement the indicator e is pivoted
on the hinge plate b, as shewn in Fig. 5 while the pin is attached to the hinge h
as shewn and bent so that when the clip is closed such pin presses upon the
spring e in the manner already described with reference to Figs. 1, 2, 3, and 4;
but, when the clip is opened, the spring e is released from such pressure as seen in
Fig. 5 thus allowing the hair spring d to come into play and automatically reset
the indicator c as likewise seen in Fig. 5.
Figures 78 and 9 shew a further modification of our invention wherein the
indicating apparatus is mounted on the top of the slide instead of at the side
thereof and the pin is dispensed with while a coiled spring d is substituted for the
hair spring d previously described. One end of such coiled spring d is attached to
the spring e which latter is mounted on the face plate 6 and elongated and bent so
as to press on the edge of the slide when closed, while the other end of such coiled
spring d is fastened to the indicator c, which, when the slide is opened, it actuates
by pulling it forwards, instead of its being pushed forwards by a hair spring in the
manner already described and so automatically resets the indicator. A groove ²
is formed in such indicator which groove takes the place of the perforation c
already mentioned. In this groove the catch e' on the spring e takes, when the
slide is closed after exposing a plate or film, thus retaining the indicator in the
proper position to register the exposure.
The dotted lines in Figure 8 shew the position of the indicator when auto-
matically reset by the act of opening the slide as already described. In this
arrangement the face plate 6 is cut away, as shewn in Figure 9, to allow sufficient
play to the spring e.
When the shutter a' is withdrawn in order to expose the plate the indicator c

page_text: is pushed backwards, thus bringing it opposite the index aperture b¹, and so
recording the exposure, in which position the indicator is retained by the catch e'
engaging in the groove c³ until the slide is opened.
Upon so opening the slide the pressure of the spring e on the edge of the slide is
withdrawn thus allowing the coiled spring d to pull the indicator forwards into the
recess g by doing which it automatically resets the indicator in readiness for the
next exposure.
We would here observe that we do not confine ourselves to the precise details of
construction hereinbefore described and shewn, as the same admit of modification
in detail without departing from the principle of our invention, which is causing an
indicating apparatus for recording the exposure of photographic plates and films to
automatically reset itself in readiness for the next exposure.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In combination with a photographic dark slide an indicating apparatus for
automatically recording the exposure of photographic plates and films which
automatically resets itself in readiness for the next exposure all substantially as
herein before described and shewn.
2. The improved construction of automatic indicating and resetting apparatus
for recording the exposure of photographic plates and films all substantially as
hereinbefore described and shewn.
3. The various modifications of such improved automatic recording and resetting
apparatus for indicating the exposure of photographic plates and films all sub-
stantially as herein before described and shewn.
Dated this foth day of July 090.
ELT & Co.,
Patent Agents, 43, Southampton Buildings, Holborn, London,
Agents for Applicants.