NEW OR IMPROVED ARRANGEMENTS APPLICABLE TO PHOTOGRAPHIC SHUTTERS WHEREBY THE DURATION OF EXPOSURE CAN BE
Year: 1884

page_text: JAMES WILLIAM THOMAS CADETT Mechanical Engineer 84 Grovo Lane Camber-
well Surrey do hereby declare the nature of my invention for NEW OR IMPROVED
ARRANGEMENTS APPLICABLE TO PHOTOGRAPHIC SHUTTERS WHEREBY THE DURATION
OF EXPOSURE CAN BE VARIED to be as follows: -
:
For slow and moderately fast exposures stops or catches are so arranged on a
Photographic Shutter that when the exposing or uncovering part of the Shutter is
liberated by moving or pressing a lever or levers or liberating catch or catches the
exposing or uncovering part of the Shutter is opened or moved so as to give
exposure and then kept open or in condition to give exposure by a catch or stop or
catches or stops until the lever or lovers or liberating catch or catches is or are
again moved or pressed or released.
When quick exposures are to be made the catch or stop or catches or stops for
keeping the oxposing or uncovering part of the shutter open or in condition of
giving exposure is or are put or moved out of gear or action so that when the
exposing or uncovering part of the Shutter is liberated by moving or pressing the
lever or levers or liberating catch or catches the exposing or uncovering part
of the shutter can open or move so as to give exposure and then without
necessitating further movement of the lever or lovers or liberating catch or catches
close or move so as to cease giving exposure.

page_text: JAMES WILLIAM THOMAS CADETT Mechanical Engineer 84 Grove Lane Camber-
well Surrey do hereby declare the nature of my invention for NEW OR IMPROVED
ARRANGEMENTS APPLICABLE TO PHOTOGRAPHIC SHUTTERS WHEREBY THE DURATION
OF EXPOSURE CAN BE VARIED and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :—
For slow and moderately fast exposures stops or catches are so arranged on a
Photographic shutter that when the exposing or uncovering part of the shutter is
liberated by moving or pressing a lever or levers or liberating catch or catches the
exposing or uncovering part of the shutter is opened or moved so as to give
exposuro and then kept opon or in condition to give exposure by a catch or stop or
catches or stops until the lover or levers or liberating catch or catches is or are
again moved or pressed or released.
When quick exposures are to be made the catch or stops or catches or stops for
keeping the exposing or uncovering part of the shutter open or in condition of
giving exposure is or are put or moved out of gear or action so that when the
exposing or uncovering part of the shutter is liberated by moving or pressing the
lever or levers or liberating catch or catches the exposing or uncovering part of
the shutter can open or novo so as to give exposure and then without
necessitating further movement of the lever or lovers or liberating catch or catches
close or inove so as to cease giving exposure.
Fig 1 shows the application of my invention to a drop shutter. a.a a represents
the movable or uncovering or exposing part of the said shutter the aperture of the
said movable or uncovering part being shown by bb bb. aaa is supposed to be
set and ready to move in the direction of the arrows either by gravity or by
springs as in any of the well known methods. The frame carrying a a a is not
shown for simplicity the nature of such frame being well known. At ca catch or
stop or projection is fixed or forms part of a a ad is a setting and liberating, catch
or lever pivotted at e with a projection of the usual kind at f. The pivot at e is
supposed in the drawing to be fixed to the frame of the shutter in the usual way or
ways. is a catch or stop which is placed through or on d and g can either be
made to screw or move through or move on & the object being to enable g to project
more or less as may be desired at has shown by the dotted lines-A spring or
springs if desired can be fixed in any of the usual ways against & at any suitable
part to keep the projection or catch at fagainst or towards the catch or stop at c.
To explain the manner of working and the use of my invention it is supposed
that a aa has a tendency to move in the direction of the arrows so that the stop
or catch or projection c is pressing on at f. If d be now moved so as to move the
catch or stop at faway from c in the direction of the arrow at c the catch or stop or
projection c will slip off and pass d at f. As d is pivotted at c the result will be to
move the catch or stop g in the direction of the dotted lines at h so that c will come
against and be stopped by g at h (as shown in Fig 2) it being supposed that g is

page_text: screwed or moved in such a position as to be able to catch or stop c in its move-
ment. After waiting such time as may be desired during which a a a is held from
moving further and exposure is being made at will d is allowed to move or is moved
back again to its original position then c slips off g and passes g at h still further in
the direction of the arrows. So far the movement and arrangements have been
shown for slow or moderately fast exposures. For quick or rapid exposures g is
screwed back or moved back away from h sufficiently so as not to catch or stop c
after c has passed f, a a a then after being liberated by c slipping pas d at f moves
without stopping throughout all its course of movement and a rapid exposure is
made.
The novelty of my invention consists in the movable or unscrewing catch or
stop which can be put in and out of gear or action at will.
It is evident that there are many variations of form and arrangement in applying
the principle of my invention to the many kinds of photographic shutters existing,
for instance it is evident that the catch or stop or projection c might be placed on
the frame of a aa and d might be pivotted on a a a instead of the frame as in
Fig 1, without departing from the principle of my said invention. Again, instead
of putting the movable or screwing catch or stop g on or through dit could be
placed on a a a at any suitable part as in Fig 3 where the movable catch or stop g¹
is fitted on to a' a¹ a¹ the action would then be as follows-For rapid exposures
the catch or stop g¹ would be pushed back to the position shown by the dotted
lines in Fig 4 at g' and also shown by the position of dotted lines at g¹ in Fig 3 in
which position it would not be caught against or stopped by the catch or lever d¹
at f¹ when c¹ is liberated. For moderately quick or slow exposures g¹ is moved to
the position shown in Fig 4 at g' so that when d' is moved away from c¹ a¹ a¹ a¹
will move in the direction of the arrows and carry g¹ past dat f¹ without
touching at f In Figs 3 and 4 g' is shown arranged for sliding being guided and
held by screws in a slot made in g' but it is clear that g¹ can be made in many
ways without departing from the principle of my said invention as for instance
g could be made to move in a groove made in a² a¹ a¹ if desired or be made to
screw in a block or other arrangement on a' a' a' or fixed in any suitable manner
so that g³ can be moved to the positions required as already indicated.
Fig. 5 shows a section of the catch or stop g' as drawn in Figs 3 and 4 the small
projection at p showing the part of g¹ which comes against d' at fl in Figs 3 and 4
the projection p being made so as to allow the other part of g' to pass over d'
when dis moved back to the position shown in Fig 3.
Fig. 6 shows the application of my invention to a shutter in which the uncovering
or exposing part is moved up and down by a pin fixed in a circular disc pivotted in
its centre to the framework of the shutter. As the kind of shutter shown in Fig 6
is well known a detailed description of it is unnecessary I therefore only describe
the application of my invention to the said shutter shown in Fig 6.
It is supposed that the disc or wheel jis set with a tendency to move round in
the direction of the arrows on j. The pin or rod k is supposed to be pressing
against the catch at the part indicated by m the catch being pivotted at na
movable catch or stop g similar in description and to effect the same purpose as g'
in Figs 3 and 4 is placed on j as shown by y at any suitable part of j.
In reference to Fig 6 for slow and moderately fast exposures g is put in the
position as shown by g in Fig 6. When the catch is moved on its pivot at n in
the direction of the arrow crossing the part of l at m will free the pink and the
disc will revolve in the direction of the arrows on j until g comes in contact with
at mg passing under the projection on lat o. When after such time as may be
desired is moved back to its original position in opposite movement indicated by
the arrow crossing l. m then frees g and thenj moves still further on until k comes
against and is stopped by o. In further explanation Fig 7 shows a section of j, g, l,
and o the projection p on 7 in Fig 7 is to catch on m Figs 6 and 7 g being so
placed that it can pass between j and o without touching o.

page_text: For rapid exposures g in Fig 6 is moved in the direction of the dotted lines so
that it can no longer touch lat m when l is moved in the direction of the arrow
crossing' so as to free m from k and then j moves round throughout its course of
movement without stopping until / comes against o when a rapid exposure is
completed.
.
It will be seen that there is considerable variety in the possible application of my
invention to photographic shutters without departing from the principle of my
said invention.
said
Having now particularly described and ascertained the nature of my
invention and in what manner the same is to be performed I declare that what
I claim is
:
The use of a movable catch or stop which can be put in and out of action or gear
substantially and for the purpose as shown in Figs 1 and 2 and represented by g.
In Figs 3 and 4 by g¹ also as shown by Fig 5 and in Figs 6 and 7 by g and p.
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