Year: 1886

page_text: I CHARLES DAY DURNFORD of the Ordnance Store Department Edinburgh
in the county of Mid Lothian North Britain Major and Assistant Commissary
General do hereby declare the nature of this invention to be as follows:-
The object of my invention is to produce a shutter for use with photographic
cameras which can be used either as an instantaneous shutter or for longer
exposures as may be desired or for the production of double exposures that is to
say exposures producing the effect of the use of stops or diaphragms of different
sizes during practically the same exposure by the which may be obtained the
minute definition of the small stop with the brilliancy and softness of the large
stop.
This shutter is preferably used between the lenses when a double combination
lens is used but several of its component parts are adapted for use when the shutter
is fitted in front of or behind the lenses. With this shutter the ordinary stops or
diaphragms may be used these stops and the slide or drop of the shutter being
preferably placed in as close a juxtaposition as is possible.
This shutter is similar in its action and somewhat similar in its construction to
an ordinary drop shutter but the rapidity of the drop is preferably increased as
may be desired by the action of a wire or other suitable spring one end of which
is secured to a pivot placed in a light tight casing at or near the side of the lens
tube while the other end passes through a slot in the lens tube to a staple or other
appliance in the drop or slide and through the same so that when this spring is in
tension the drop or slide is forced downwards at a quicker speed. This arrange-
ment is similar to that described more fully in the specification filed in pursuance
of my application for a Patent dated the 15th of September 1885 and numbered
10896. Another method of fitting this spring consists in mounting the pivot
thereof on an arm or other projection fitted on the frame of the shutter or on the
lens tube or elsewhere while the other end of the spring is connected to or held by
or on the top edge of the slide or drop which is always outside the lens tube
preferably in such a manner that this end of the spring can be disconnected
therefrom when not required. When the spring is connected or attached to the
drop or slide the tension thereof and the consequent rapidity of motion can be
regulated by a lever attached to the pivot of the spring by the which the same
can be turned and when required held in position by a ratchet rack as is more
TD 017

page_text: fully described in my said specification No. 10896 of 1885 or the tension thereof
may be regulated by attaching a chain to the end of the lever and hooking the
desired link of this chain on a pin or jamming the chain between two pins on the
frame of the shutter or elsewhere or the tension may be regulated by any other
usual devices.
The slide or drop and the aperture or apertures therein may be of any desired
shapes and sizes. When a double exposure is desired a narrow vertical slot may.
be made towards the lower part of the slide which slot at its upper end opens into
an upper and larger aperture preferably of the same size as or a little larger than
the largest stop or diaphragm that is to be used or two separate apertures may be
made of which the smaller is the lower one. Suitable recesses or notches are
made in the sides of the slide or drop in the proper positions to receive one of the
two catches that are connected together or formed in one piece so as to create a
double catch which is actuated in any convenient manner preferably by the usual
tube and collapsible ball acting on a pneumatic piston in a tube. This double
catch preferably consists of a wire or rod which moves freely across the front or
back of the drop or slide preferably just above the lens tube on which are formed
or to which are attached the two catches so situated that they cannot be both
engaged in the notches or recesses in the drop or slide at one and the same time.
When one catch is engaged in the lower notch or recess the slide closes the
aperture in the position required before exposure and when this catch is retired the
slide or drop falls until the other catch engages in the second notch preferably on
the other side of the slide or drop. In this position the light is admitted through
the narrow slot or smaller aperture and when this exposure is finished the second
catch can be retired when the slide or drop falls home thus allowing a rapid flash
of light through the upper or larger opening and again closing the aperture or the
notches may be so placed that the first catch holds the drop or slide in position to
admit light through the narrow slot or lower aperture and the second catch holds
the same to admit light through the upper or larger opening or a third notch may
be added to combine both these arrangements or otherwise.
When only an instantaneous exposure is required a stop can be applied to the
double catch so as to permit the release of the first catch but prevent the advance
of the second catch sufficiently far to engage the other notch.

page_text: I CHARLES DAY DURNFORD of the Ordnance Store Department Edinburgh in
the county of Mid Lothian North Britain Major and Assistant Commissary General
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
The object of my invention is to produce a shutter for use with photographic
cameras which can be so used either as an instantaneous shutter or for longer
exposures as may be desired or for the production of double exposures that is to
say exposures producing the effect of the use of stops or diaphragms of different
sizes during practically the same exposure by the which may be obtained the
minute definition of the small stop with the brilliancy and softness of the large stop.
This shutter is preferably situated and fitted between the lenses when a double.
combination lens is used but it may also be situated and fitted in any other
desirable or suitable position and when the ordinary stops or diaphragms are used
therewith the same are preferably placed in as close a juxtaposition with this
shutter as is possible or practicable and are preferably inserted from the side.
instead of from the top as is usual.
•
In the accompanying drawing I have shewn several forms of this
and various methods of actuating and governing the same.
Figure 1 is an elevation of one style of my complete apparatus.
Figure 2 is a plan of the same.
my shutter
The shutter A passes through a slot in the lens tube B in a similar method to
the ordinary drop shutter and for a single exposure this shutter A has an aperture
D as has the ordinary shutter. An horizontal double catch E is mounted on the.
lens tube B preferably behind the shutter A on which an elbow is formed on each
side of the shutter so arranged and situated that both elbows cannot touch the
shutter A at one and the same time and this double catch E is or may be actuated
in the usual manner by a collapsible ball acting through a flexible pipe on a
pneumatic piston in the tube F. Suitable notches or recesses are made in the sides
of the shutter A in the proper positions as is hereinafter explained to receive one
of the two elbows of the catch E. In the position shown in Figure 1 the
elbow of the catch E is engaged in the notch H and the shutter A closes, the
aperture in the lens tube as is required before exposure. The catch E is then
moved as aforesaid releasing the elbow thereof from the notch H. and the shutter A
falls until the other elbow of the catch E which has been duly advanced by the
same motion that released the elbow from the notch H engages in the recess K
under the shoulder formed at the upper end thereof on the other side of the
shutter A which shoulder K is so situated that the aperture in the lens tube B is
now uncovered being in conjunction with the aperture D and the desired exposure
can be given when the catch E is brought back to its original position releasing.
the elbow thereof from the recess K and the shutter A falls home again closing the
aperture in the lens tube B.

page_text: When an instantaneous exposure only is required a T shaped stop L can very
conveniently be pivotted on the lens tube B so formed that when this stop L is in
the position shewn in these Figures although the first elbow of the catch E can be
engaged in and released from the notch H as hereinbefore described the other
elbow of the catch E cannot be advanced sufficiently to engage in the recess K but
when the stop L is moved into the position shewn by dotted lines in Figure 2 the
longer exposure can be given as hereinbéfore described.
When an extremely rapid motion of the shutter is desired an arm or projection M
may be fitted on the lens tube B or elsewhere in the end whereof is a pivot round
which a spring N can be coiled the other end of which spring N is connected
to the top edge of the shutter A which obviously is always outside the lens tube B.
To regulate the tension of this spring. N and thereby the consequent rapidity of
the motion of the shutter A a lever P can be fitted on the pivot of the spring N
which lever P can be moved by the chain P¹ and secured in such position by
hooking the desired link of this chain P¹ on a pin or by jamming the same or
otherwise or the tension may be regulated by any other usual or suitable devices.
It is extremely convenient to fit this arm M in such wise that the same can be
removed when not required and I shew in Figure 1 a suitable method in which a
socket M is formed on the upper part of the bracket F¹ that supports the
pneumatic tube F into which socket M¹ a pin on the lower part of the arm M can
pass and be caught by a spring or otherwise and in this case the end of the
spring N is so connected to the shutter A as to be readily disconnected therefrom
when required.
Figure 3 is an elevation of another style of my complete apparatus.
Figure 4 is a plan of the same.
The shutter A is made and fitted as is hereinbefore described. as also is the
double catch E except that the same is mounted preferably before the shutter A.
The stop R is pivotted on the side of the pneumatic tube F or thereabouts and in
the position shewn in these Figures only allows an instantaneous exposure in
manner hereinbefore described but when this stop R is moved into the position
shewn by dotted lines in Figure 3 the longer exposure can be given as the elbow
of the catch E can be advanced sufficiently to engage in the recess K in the
shutter A. In this case the extremely rapid motion is given to the shutter A
when desired in manner described in the specification of the Patent granted unto
me on the 15th day of September 1885 numbered 10896 in which a spring is
coiled round a pivot in the light tight casing T on the side of the lens tube B
which spring passes through a slot in the side of the same to a staple or other
appliance on the lower part of the shutter A and the tension of this spring can be
regulated by the lever T¹ attached to the pivot of the spring for the purpose
hereinbefore stated.
Instead of springs as hereinbefore described I can in every case use elastic bands
which could be passed round the lens tubes and over the tops of the shutters to
produce the extremely rapid motion of the shutters when desired.
The catch also by which the shutter is held before exposure can be forced into
such position very conveniently by a spring preferably placed inside the pneumatic
tube and acting on the piston therein the pneumatic force required for releasing
this catch being given against this spring.
To produce the double exposure hereinbefore described I form the shutter in the
following manner of the which one example is shewn in Figure 5.
A large aperture D is formed in the proper position in the shutter which
aperture D is preferably of the same size as or may be a little larger than the
largest stop or diaphragm that is to be used and below this aperture D is made a
much smaller aperture V preferably of the same size as one of the smallest stops
or diaphragms or thereabouts and this aperture V may be circular or square and
may be connected with or may be entirely separate from the larger aperture Dor
may consist of a narrow vertical slot which also may be connected with or may be
entirely separate from the larger aperture D.

page_text: When this shutter is to be used the notch H aforesaid is preferably so situated
that when the elbow of the catch E is engaged therein the aperture in the lens
tube is closed. Then if instantaneous exposure is not desired the stop L or R is
properly placed as aforesaid therefor the catch E is released from the notch H the
shutter drops and the other elbow of the catch E engages in the recess K as
hereinbefore described in which position the light is admitted through the smaller
aperture V. When this exposure is finished this elbow of the catch E is released
from the recess K and when this shutter is made as shewn in the drawing the
shutter again drops until the former elbow of the catch E engages in another
similar recess W under a shoulder formed at the upper end thereof on the other
side of the shutter that is to say the same side thereof as is the notch H in which
position the light is admitted through the larger aperture D and the desired
exposure can be given when the catch E is released from the recess W and the
shutter falls home again closing the aperture in the lens tube. According to
another mode of using and working this shutter when the exposure through the
smaller aperture V is finished the shutter can be allowed to fall home at once
whereby only a rapid flash of light would be allowed through the larger aperture D.
This could be effected either by dispensing with and not making the recess W
aforesaid or by so moving the stop L or R that the catch E could not engage in
this recess W. This shutter so made can also when required be caused to give
only an instantaneous exposure by so arranging the stop as hereinbefore described
that when the catch is released from the notch H the shutter at once falls home
thus allowing a rapid flash of light first through the smaller aperture V and then
through the larger aperture D.
I have thus described and I have shewn in the drawing very convenient forms
of this my improved shutter and of the several parts in connection there with and
by which the same is worked but I do not limit myself thereto for this my shutter
and the several parts that actuate and work and govern the same may be so
arranged and fitted and applied and formed as may be expedient or desirablo in
each particular case.
Having now. particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The combination in and with the shutter A of the double catch E and the
notches or recesses H and K substantially as hereinbefore described.
2. The combination in and with the shutter A of the double catch E.the notches
or recesses H and K the arm M with spring N and the lever P substantially as
and for the purpose herein before described and declared.
3. The combination in and with the shutter A of the double catch E the notches
or recesses H and K. the casing T with spring and the lever T¹ substantially as
and for the purpose herein before described and declared.
4. The combination with the shutter and the appliances thereof herein described
and claimed of the stop L or R substantially as set forth.
5. The combination in a shutter of the larger aperture and the smaller aperture
substantially as and for the purpose hereinbefore described and declared.
6. The combination in the shutter A of the two apertures D and V and the
notches or recesses H K and W substantially as hereinbefore described.