Year: 1885

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 and provide for use with photographic
cameras a shutter that shall be extremely simple in construction while very
effective and sure in operation and by which an exposure either instantaneous or
of any desired duration can be given to the plate in the camera and this shutter
can be placed inside the cylinder or tube in front of the lens or elsewhere if desired
as well as outside the same as is usual.
I carry out this object by forming a shutter of any desired size sufficient to close
or cover the aperture in a frame made therefor-through which aperture the
exposure is given to the plate in the camera and this shutter is so fitted as to be
capable of revolving in or on the frame through a semicircle thereby reversing itself
thereon and also of sliding upwards and downwards or otherwise in or on the said
frame whereby a cycle of movement is created as follows. When the shutter is in
position to cover the aperture in the frame and prevent any light passing there-
through it is parallel with the plane of the said frame and the said shutter is then
caused very rapidly to revolve through a semicircle preferably on its upper edge or
part or to reverse itself upside down and when this movement is completed to slide
in or on the said frame preferably downwards as rapidly thus again closing the
said aperture and being parallel with the plane of the said frame. This action or
cycle of movement aforesaid can easily be made so rapid that only an instantaneous
exposure is given to the plate in the camera and to give a longer exposure thereto
when required any suitable catch can be provided to stop the shutter in its afore-
said revolution when at right angles to the plane of the frame or thereabouts and
bold it in this position and then when the desired exposure has been so given this
catch can be retired and the said shutter be allowed to complete its semirevolution
and to slide as aforesaid.
A convenient method of fitting this shutter to render the same capable of these
two movements consists in forming projections or lugs on each side of the said
shutter or in attaching a cross bar thereto which duly projects on each side at one
of the ends thereof which projections or lugs engage in grooves preferably vertical
formed in or on the frame and act as and constitute the pivots on which the said

page_text: shutter revolves and the guides to cause the same to slide in the proper position in
or on the said frame and the said movements can conveniently be effected by a
spring coiled or otherwise or by any elastic material which can be applied to any
convenient part of the said shutter to cause the same first to revolve through a
semicircle and then to slide in or on the said frame as is aforesaid.
To set this shutter ready for giving an exposure these movements are reversed
and the shutter can be made by hand or otherwise to slide in or on the frame and
then to revolve through a semicircle to its required position over the aperture in
the frame where it can be held by any suitable catch and when a spring or elastic
material is used to effect the exposure this action aforesaid puts the desired
tension there upon which tension can also be increased or decreased as desired by
any usual or convenient appliances.
As is aforesaid the shutter is preferably caused to revolve on its upper edge or
part and then to slide downwards in or on the frame though the said shutter can
also be caused to revolve on any other edge or part thereof in any other direction
and be caused to slide accordingly.

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 and provide for use with photographic
cameras a shutter that shall he extremely simple in construction while very
effective and sure in operation and by which an exposure either instantaneous or
of any desired duration can be given to the plate in the camera and this shutter
can be placed inside the cylinder or tube in front of the lens or elsewhere if desired
as well as outside the same as is usual.
I carry out this object by forming a shutter of a single piece of a rigid and
opaque material and of any desired shape and size sufficient to close or cover the
aperture in a frame made for the said shutter through which aperture the exposure
is given to the plate in the camera and this shutter is so formed and fitted as to be
capable of revolving in or on the said frame through a semicircle thereby reversing
itself thereon and also of sliding upwards and downwards or otherwise in or on
the said frame whereby a cycle of movement is created as follows. When the
shutter is in position to cover the aperture in the frame and prevent any light
passing therethrough the said shutter is parallel with the plane of the said frame
and the said shutter is caused very rapidly to revolve through a semicircle
preferably on its upper edge or part or to reverse itself upside down and when this
movement is completed to slide in or on the said frame preferably downwards as
rapidly thus again closing the said aperture and being again parallel with the said
plane of the frame. This action or cycle of movement aforesaid can easily be
made so rapid that only an instantaneous exposure is given to the plate in the
camera but to give a longer exposure thereto when required any suitable catch can
be provided to stop the shutter in the aforesaid revolution when at right angles to
the plane of the frame or thereabouts and hold the said shutter in this position
and then when the desired exposure has been so given this catch can be retired
and the said shutter be allowed to complete the semirevolution and to slide as is
hereinbefore described.
Any convenient arrangement of springs weights or other appliances may be
employed to produce and create the action or cycle of movement herein before
described. I shew in the accompanying drawing a very suitable and effective
method of fitting this shutter to render the same capable of these two movements
aforesaid.
Figure 1 is a front elevation of the frame of the shutter with the aperture therein
closed by the said shutter in one position. Figure 2 is a rear elevation of the
frame. Figure 3 is a transverse horizontal section taken at a. b. in Figure 1.
Figure 4 is a transverse vertical section taken at c. d. in Figure 1. Figure 5 is a
front elevation of the frame of the shutter with the aperture therein closed by the
said shutter in a second position.

page_text: On
The frame A is made of the required size and shape and of any usual and
convenient material and in the said frame A is made the usual aperture B through
which aperture B the desired exposure is given to the plate in the camera.
the two lateral vertical sides of the frame A are formed the grooves C which
grooves C are preferably broader at the tops or upper ends than at the bottoms or
lower ends thereof as is shewn in Figure 4 for the purpose hereinafter declared.
A shutter D is made of wood or other rigid opaque material and of sufficient size
to close or cover the aperture B but not of sufficient breadth to enter the grooves C
and at or on or near one end of the said shutter D are formed in any convenient
manner preferably in one and the same piece therewith the projections or lugs D¹
on each side of the said shutter D which projections D¹ engage in the said grooves C.
To the end of the shutter D opposite to that on which the projections D' are
formed and on each side thereof the ends of the strips or ribands of elastic
material E are attached which strips E pass up the sides of the said shutter D and
over the said projections D¹ thereon through the apertures F. in the frame A and
are then secured on the back of the frame A in any convenient manner.
When a
slow action of this apparatus is required it is preferable to increase the lengths of
these strips or ribands of clastic material and I therefore proceed as follows. The
strips E after passing through the apertures F as aforesaid are led over rollers G
mounted in the rear parts of the said apertures F thence down the back of the
frame A and round rollers H thereon near the bottom of the said frame A thence
again up the said back of the frame A and round rollers K thereon near the top of
the said frame A and the ends of the said strips E are attached to a regulating pin L
mounted in a bracket L' on the said back of the frame A by the turning of which
pin L the tension to be given to the said strips E can be regulated or one long
strip E can be used in the same manner the middle of which would pass through
the said pin L or be attached thereto. The tops of the rollers G are a little below
the level of the top of the shutter D when the same is in position for closing the
aperture B and a shallow recess M is made horizontally across the face of the
frame A at the same level as is shewn in Figure 4 all for the purposes hereinafter
declared. A suitable catch N is pivotted on the lower part of the frame A which
catch N when formed as shewn in Figure 1 is actuated in any usual or convenient
manner by an horizontally acting appliance.
To give an instantaneous exposure with this shutter I proceed as follows. The
shutter D is placed in position for closing the aperture B with the projections D¹
thereon uppermost as shewn in Figure 1 in which position a great tension is given
to the strips E which tension also can be increased if desired by turning the pin L
and the said shutter D is secured in this position by the catch N. While the shutter D
is in this position no light can pass through the aperture B as the lower part of
the said shutter D is pressed against the face of the frame A by the catch N and
the upper part of the said shutter D is pressed against the said face of the frame A
by the strips E of elastic material passing over the projections D'. The catch N
can then be retired by the actuating appliance when the tension of the strips E draws
the upper edge of the shutter D into the recess M causing the said shutter D
to turn on the said upper edge thereof and on the projections D₁ as on pivots until
the said shutter D has revolved through a semicircle and is again parallel with
the plane of the frame A when the downward tension of the said strips E causes
what was as aforesaid the said upper edge of the shutter D but is now the lower
edge thereof to slip out of the said shallow recess M and the said shutter D
therefore slides downwards on the said frame A being guided in this descent by the
said projections D¹ in the grooves C until the said shutter D has reached the
position as shewn in Figure 5 with the said projections D¹ thereon lowermost and
the aperture B is again closed as is desired.
The rollers G are below the level of the top of the shutter D as is aforesaid in
both positions so that when the same is in the first position as shewn in Figure 1
the upper edge of the said shutter is ensured being drawn into the recess, M thus
commencing the revolving motion and when the same is in the second position as

page_text: shewn in Figure 5 the said shutter D is ensured being brought down to the bottom
of the frame A and held in such position to close the aperture B. The grooves C
are made broader at the tops or upper ends than at the bottoms or lower ends
thereof as is aforesaid so that while sufficient room or space is given for the
projections D¹ freely to revolve in the said grooves C at the said tops or upper ends
thereof the said grooves C at the said bottoms or lower ends thereof will press the
lower part of the shutter D against the face of the frame A by and through the
said projections D₁ when the said shutter D is in the second position as shewn in
Figure 5 while the upper part of the said shutter D is pressed against the said face
of the frame A by the strips E of elastic material and thus no light can pass
through the aperture B when the said shutter D is in this position.
When however it is desired to give a longer exposure to the plate in the camera
I preferably pivot on one side of the frame a lever similar to and fitted in the same
manner as the lever described in the complete specification of, my invention that
was filed on the 31st day of December 1885 under No. 10896. of 1885. This lever
is also shewn in Figure 5 of the accompanying drawing and is indicated by the
letter P one arm P₁ of which lever is the catch for holding the shutter D in its first
position as does the catch N hereinbefore described and the other arm P¹ is the
catch that stops the said shutter D in the revolution thereof as aforesaid when at
right angles to the plane of the frame A or thereabouts and holds the said shutter D
in such position until the desired exposure has been given to the plate in the camera
when the said catch P is retired and the said shutter D is allowed to complete
the semirevolution and to slide downwards in the grooves C as is hereinbefore
described and the lever stop R is fitted on the bottom of the said frame. A to
regulate the amount of movement that is to be allowed to the said lever P so that
this double catch can be used both for instantaneous and for lengthened exposures
as may be desired as is more fully and, particularly described in the completo
specification of my invention No. 10896 of 1885 herein before mentioned.
The frame A may also be fitted as shewn in the drawing with a short collar T to
fit over the end of the cylinder or tube in front of the lens or may be so shaped as
to be capable of being placed inside the same or elsewhere as may be desired.
I can also very conveniently fit a spring V on the upper part of the face of the
frame A on which is supported an elastic or other buffer W to receive the impact of
the shutter D as the semirevolution thereof herein before described is completed and
thus prevent any vibration.
I have thus described and I have shewn in the drawing a very suitable and
effective method of fitting this my reversing and sliding shutter but I would have
it clearly understood that I do not limit myself thereto for any method of applying
elastic material or springs or weights or other appliances to the said shutter may
be used that will cause the same to go through the prescribed cycle of movement
that is to say first to revolve through a semicircle or to reverse itself in or
on the frame and then to slide as required in or on the said frame.
I can
also form the shutter itself of any desired and suitable shape and in any desired
manner. For instance the edge of the shutter between the two projections or
lugs thereof can be formed of a concave or convex shape instead of straight
or level as shewn in the drawing and the face of the frame would be formed
in accordance therewith in the position where the shallow recess is made as herein-
before described. Again when an extremely speedy action is desired I may prolong
the shutter beyond the projections or lugs or formn the said projections or lugs some
little distance from the edge of the said shutter instead of at or on the said edge
as shewn in the drawing and I should then hollow out the face of the frame so
that this edge of the said shutter could freely revolve in such hollow preferably
without any contact with the same and thus the said shutter would revolve mainly
or solely on the said projections or lugs as on pivots and in this case the elastic
material or actuating appliance would preferably pass over this edge so prolonged
beyond the said projections or lugs to give an increased leverage whereby the
revolving motion is commenced at a more rapid rate. Again when large apertures

page_text: are to be used or when from any cause a large shutter is required I can very.
conveniently fit two of these my shutters to close or cover the said aperture each
of which shutters would be formed and fitted as herein described and may preferably
overlap each other at or near or about the centre of the said aperture or otherwise
in both positions to entirely exclude the light. It is also sufficiently obvious that
when required the shutter can be arranged to revolve on other of its edges or in
other directions or otherwise as well as on its top edge as herein before described and
as shewn in the drawing in all of which cases the said shutter would be caused to
slide in the due corresponding manner. It is evident also that all the various parts
of this apparatus may be made of any desired and convenient shape and form save
only that the grooves if any must be parallel with each other to allow the projec-
tions or lugs on or attached to the shutter to slide freely therein and such catches
may be used for both the purposes hereinbefore described as may be suitable 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
The photographic shutter which revolves through a semicircle or reverses itself
and then slides in or on the frame thereof for the purpose hereinbefore declared.