IMPROVEMENTS IN PHOTOGRAPHIC SHUTTERS
Year: 1885

page_text: I CHARLES DAY DURNFORD of the Ordnance Store Department Elinburgh in
the County of Midlothian North Britain Major and Assistant Commissary General
do hereby declare the nature of my invention for IMPROVEMENTS IN PHOTOGRAPHIC
SHUTTERS to be as follows :-
The object of my invention is to produce and provide a shutter for use with
photographic cameras that shall be capable of being used either, as an instantaneous
shutter or as a shutter that will allow of a longer exposure being given to the
plate in the camera as may be desired, and I also can so form this shutter that the
frame thereof can be placed inside the cylinder or tube in front of the lens of the
camera.
To carry out this object I make a frame. On either side of the front of the
aperture of which frame is a vertical groove. Between these grooves the shutter
can slide when opening and closing the aperture. At or near the top or upper
edges of these grooves a metal or other roller is pivotted which may be covered
with india rubber. This roller extends from one side of the frame to its opposite
side and is so placed that when the shutter is in position in the grooves the said
roller crosses the front of the top of the shutter.
The shutter is composed or made of thin wood or other sufficiently rigid and
light material, and to the lower extremity of this shutter is attached an extension
or continuation of flexible material suitable for and capable of sliding in the
grooves with the rigid portion. This flexible extension is of such a length that
when the shutter is drawn or raised in the grooves a sufficient distance to free the
aperture the rigid portion can be turned down as a lid or flap in front of the
aperture of the frame and in front of the edges of the grooves which had previously
contained it, thus again closing the aperture but with the shutter reversed. While
in this position the flexible part will partly surround the aforesaid roller its lower
extremity being still in the grooves a sufficient distance to prevent the entrance of
light. The rigid portion may be held in this new position by means of a suitable
catch. It will be seen that when the motive power (which will be hereinafter
described) is applied in a downward direction to the flexible portion remaining in
the grooves and the catch is released the rest of the flexible portion is drawn
round with and over the roller and the rigid part in following the flexible part
opens like a flap and when vertical is carried down the grooves to its first position

page_text: thus again closing the aperture. To combine this instantaneous movement and
action aforesaid with a movement and action that will admit of a longer exposure
1 pivot a double catch consisting of two arms with a catch at the end of each arm
in such a position that one catch shall engage and hold the rigid flap aforesaid
when drawn over the roller and reversed as before described, and the second catch
shall engage and hold it when in a nearly horizontal position for purposes of
focussing or of lengthened exposure. These catches are so fitted that they cannot
both be in position for engaging at the same time. When the first catch is
disengaged by any suitable and usual appliance the second is advanced and
engages. But when an instantaneous exposure is desired I can so apply a stop to
the catch as to prevent the second catch advancing sufficiently far to engage the
shutter thus allowing it be instantly drawn into the grooves.
The motive power of the shutter consists of a wire or other convenient spring
one end of which may be coiled round and firmly attached to a metal rod or pivot.
This pivot is mounted in a suitable case at or near the side of the shutter-The
other end of the spring is carried to within the frame of the shutter through a
slot in one of the containing edges of the grooves and is attached to the lower
extremity of the flexible portion of the shutter in such a manner as to allow of a
slight lateral movement to compensate for the arc which it traverses when the
shutter is raised or lowered in the grooves.
This end or arm of the spring is so bent as to avoid crossing the aperture of
the shutter when it is open. The motion of the shutter is caused by the tendency
of this arm of the spring to drag the shutter downwards when the spring is in
tension.
I can control and regulate the tension of the spring and consequently the
rapidity of the exposure by means of an arm or lever from the aforesaid rod or
pivot by which the pivot can be turned so as to tighten or loosen the tension of
the spring and the lever retained in the desired position by means of a ratchet.

page_text: improvements in Photograpnio snutters.
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 and provide for use with photographic
cameras a shutter that shall be capable of being used either as an instantaneous
shutter or as a shutter that will allow of a longer exposure being given to the
plate in the camera as may be desired and I can also so form this shutter that the
frame thereof can be placed inside the cylinder or tube in front of the lens of
the camera when desired.
In order the more clearly to explain my invention and in what manner the same
is to be performed I refer to the accompanying drawing in which I have shewn a
very convenient form of this apparatus.
Figure 1 is a front elevation of the apparatus with the aperture in the frame
close by the shutter in one position. Figure 2 is a transverse vertical section of the
same with the aperture in the frame closed by the shutter in a second position and
taken at a. b. in Figure 1. Figure 3 is a transverse horizontal section of the same
with the shutter in the second position and taken at c. d. in Figure 2. Figure 4
is a front elevation of the same with the aperture in the frame open for exposure
of the plate in the camera or otherwise. The letters refer to the same parts in all
the Figures.
On
The frame A is made of a suitable size and shape and of any usual or convenient
material and in the solid back thereof is formed the usual aperture B through
which aperture B the desired exposure is given to the plate in the camera.
the inner or facing surfaces or sides of the bottom piece and the two side pieces
of the frame A is formed a continuous shoulder C in such a manner that a groove D
is created between the said shoulder Cand the solid back of the said frame A and a
recess E exactly similar in size to the said groove D is created on the front face of
the said frame A and across the said frame A at or near the top or upper part
thereof an horizontal roller F which may be covered by india rubber is pivotted
in and borne by the said shoulders C. A shutter H is made of thin wood or other
light but rigid material which fits the frame A and is capable of sliding in the
grooves D and entering the recess E and to one end of this shutter H is attached
an extension H¹ of some opaque but flexible material also capable of sliding in the
Baid grooves D and of such size and dimensions as may be necessary for the
purpose hereinafter specified. A convenient and suitable method of fitting this
combined shutter is shewn in Figure 2 where the whole shutter is lined by the
flexible material H" and the flexible extension H' thereof is stiffened by transverse
laths of a rigid material preferably the same as that of which the shutter H is
made. On the face of the frame A preferably on one of the side pieces thereof
as shewn a lever K is pivotted which has two arms one of such arms K'
constituting a catch in the centre or thereabouts of the face of the bottom piece of

page_text: the said frame A while the other arm K" constitutes a catch which reaches up a
certain desired distance at or near the level of the top of the said frame A. The
lever K is preferably actuated in the usual manner by a pneumatic collapsible ball
operating on a piston or a diaphragm in the tube L secured on the side of the
frame A which piston or diaphragm is connected with the stud Kill on the said
lever K. On the outer surface or side of one of the side pieces of the frame A
preferably on the opposite side piece to that on which the lever K is pivotted as
aforesaid is attached a casing M in which is mounted a pivot pin or drum N and
on this pin or drum N is coiled a spring P which spring P passes through a
suitable slot or aperture formed therefor through the shoulder C and the end
thereof is connected to the lower end of the flexible extension H' of the shutter H
preferably by passing the same through an eye S thereon as shewn so that the
said shutter H may travel in a right or straight line though the end of the said
spring P describes an arc. A lever handle T is fitted on the pivot pin or centre
pin of the drum N to regulate the tension to be given to the spring P and a
ratchet rack V is fitted on the casing M to retain the said handle T in the desired
position while the said spring P is so bent as to avoid crossing the aperture B when
the shutter H is raised as is hereinafter described. A suitable lever stop W is
fitted on the outer surface or side of the bottom piece of the frame A to regulate
the amount of movement to be allowed to the lever K.
The action of and method of using this apparatus is as follows.
When an instantaneous exposure of the plate in the camera only is desired to be
given the shutter H is at first in the position shewn in Figure 1 and the said
shutter H is lifted up in the grooves D until the end of the flexible extension H¹
thereof is clear of the aperture B when this flexible extension H' is bent round the
roller F and the rigid shutter H is turned down and caused to enter the recess E
and then the catch K¹ is lifted to secure the same in this position as shewn in
Figure 2 and no light can pass through the said aperture B as the said rigid
shutter H closes the front of the frame A and a sufficient length of the said flexible
extension H' thereof is still in the said grooves D to close that part of the
apparatus and when the handle T is in the position shewn in Figure 1 or in other
position as may be required the necessary great tension is given to the spring P.
The stop W is then placed as shewn in Figure 1 and when the catch K¹ is released
by the pneumatic arrangement aforesaid or otherwise the spring P very rapidly
draws the flexible extension H' round the roller F and the rigid shutter H
following the same is first opened like a door or flap and when vertical is carried
down the grooves D to the first position as shewn in Figure 1 thus again
closing the aperture B. This movement aforesaid can be rendered so rapid that
only an instantaneous exposure is given through the aperture as is desired.
But when a longer exposure is desired for any purpose the shutter H is again
brought in manner as hereinbefore described into the position shewn in Figure 2
but the tension of the spring P is preferably reduced by moving the handle T
therefor as shewn in Figure 4 or otherwise and the stop W is now placed as shewn
also in this Figure 4 and when the catch K' is released as aforesaid the increased
amount of movement by the said stop W allowed to the lever K causes the
catch K to stop the rigid shutter H in its opening movement as aforesaid when
in an horizontal position or at right angles to the frame A or thereabouts and to
hold the same in such position as is shewn also in this Figure 4 until the desired
exposure has been accomplished when the said catch K¹ is retired in a similar
manner and the movement of the said shutter H as herein before described is
completed thus again closing the aperture B as is desired.
Thus and in this manner either an instantaneous exposure can be given to the
plate in the camera or an exposure of any desired length can be given thereto or
otherwise by one and the same shutter as is desired.
I would state in conclusion that I consider the apparatus as hereinbefore
described and as shewn in the drawing to be extremely suitable and convenient
for carrying out my object as hereinbefore declared but it is obvious that I do not

page_text: limit myself to the exact shapes and details of arrangement and construction of
the various parts of the said apparatus as so described and shewn and to the
precise methods of fitting and actuating the same for all the said various parts of
this apparatus may be made and formed and arranged and fitted and actuated as
may be expedient or desirable in each particular case. For instance the lever K
may be pivotted on the bottom piece of the frame A instead of on one of the side
pieces thereof so as to allow of an horizontal actuating appliance instead of a
vertical one and the said lever K may be formed of any desired shape but in all
cases so that both the catches thereof cannot be engaged at one and the same time
and that in one position both catches are disengaged as is obviously necessary.
Again if I only desire to use this shutter for instantaneous exposures I should only
fit one catch to hold the said shutter in the position shewn in Figure 2. The
catch or catches also may be actuated in any usual or convenient manner and the
frame may either be formed as shewn to fit over the end of the cylinder or tube in.
front of the lens by means of the short collar X or may be formed to fit inside the
same as may be desired.
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. In a photographic shutter the combination of a rigid portion and a flexible
portion substantially as and for the purpose hereinbefore described and declared.
2. The combination of the combined shutter hereinbefore claimed the roller the
spring the groove and the recess in the frame and the catch substantially as
hereinbefore described and set forth.
3. The combination of the combined shutter hereinbefore claimed the roller the
adjustable spring the groove and the recess in the frame the double catch and the
regulating stop the whole being combined and operating substantially as herein-
before set forth.