provements in and in connection with Photographic Shutters of the Character known as "Blind Shutters."
Year: 1893

page_text: Date of Application, 18th Aug., 1893
Complete Specification Left, 18th May, 1894-Accepted, 23rd June, 1894
PROVISIONAL SPECIFICATION
Improvements in and in connection with Photographic Shutters of
the Character known as "Blind Shutters."
I, HENRY COOк, M.D. F.R.C.P. Lond. J.P. etc., etc., Priors Mesne, Lydney,
Gloucester, Surgeon General retired, Her Majesty's Indian Army, do hereby
declare the nature of this invention to be as follows:-
This invention relates to shutters for photographic purposes of the character
generally known as "blind shutters " or "roller-blind shutters" and my present
invention is designed to produce a shutter which will (inter alia) afford the
following advantages combined in one shutter, viz. :—
(1) A safety blind shutter.
(2) A focal plane shutter.
(3) Capable of regulating the duration of exposure.
(4) Capable of regulating the size of the exposing aperture at each successive
exposure without taking to pieces or disturbing the camera.
(5) Capable of giving varying speed of travel during exposure so that more
exposure can be given to one part of the sensitive surface than to the other.
(6) Capable of working close up to the sensitive surface.
(7) A double blind shutter occupying very little space.
Besides affording (inter alia) the combined advantages and facilities above set
forth the whole of the parts are simple and economical in construction and not
easily liable to get out of order.
My present invention is as follows:
In a suitable frame or support I arrange and mount two separate and distinct
roller blinds which for the sake of clearness I will term the first and second blind
and these two blinds are advantageously mounted and arranged to travel in
parallel planes or thereabouts and in close proximity to one another.
The first blind is mounted on two rollers or equivalents so as to be capable of
being wound off one roller on to the other to set the shutter ready for giving an
exposure and thereby winding or straining a spring or springs the reaction of which
will wind back the blind when same is released and the exposure given through an
aperture or opening in the said blind thus passing across the path of the lens-all
of which per se is old and well-known in the numerous existing forms of blind
shutters.
A second and similar blind is mounted and arranged in close proximity to the
first blind but entirely separate therefrom being separately actuated by separate
setting device separate spring or springs acting on separate rollers but simultaneously
released with the said first blind and each of these two separate blinds may in
setting be caused to travel either the maximum distance or less and can be set and
held in any desired position-thus the first blind can be first caused to travel its
maximum distance and there set ready for the release-the second blind meantime
acting as a safety blind while setting the first then the second blind can be caused to
travel its maximum distance or any less distance and is then caught and held by
the releasing device (which simultaneously releases both blinds as hereinafter
described) the first blind now acting as a safety for the second blind while setting
the latter.
The two blinds may be mounted in opposite directions on their respective rollers
so that by each winding outwardly the part of each blind between the rollers can

page_text: be brought very close to one another and if desired travel in guideways or recesses.
along their edges so as to prevent the one blind catching or interfering with the
other.
For the purpose of simultaneously releasing both blinds I arrange and mount a
ratchet wheel or equivalent on the axle or one end of one roller of the first blind
and a corresponding ratchet wheel on one end of one roller of the second blind and
these ratchet wheels will be (or may be) right and left-handed. A releasing rod
or lever extends to the exterior of the camera case or so as to be capable of being
grasped or touched by the operator and has two pawls extending therefrom which
pawls are respectively kept pressed into gear with the said ratchet teeth by means
of spring or equivalent normally pressing said releasing rod in such manner as to
keep the said pawls thereof continually in gear with the said ratchet wheels
respectively.
Thus when either blind is being set or wound ready for giving an exposure the
teeth of the ratchet wheel being revolved will run past the pawl while immediately
the setting or winding gear is released the pawl will engage in the next adjacent
tooth on said ratchet wheel and similarly with the other blind while on pressing or
moving the aforesaid releasing lever the two pawls will be thereby simultaneously
moved clear of the two ratchet wheels and thereby the two blinds will be
simultaneously released.
Any other equivalent or suitable simultaneous releasing device may be adapted
or used in place of the foregoing if desired.
Any suitable means may be used for winding or setting each blind separately-
for instance a pulley on the end of the roller opposite the aforesaid ratchet wheel
may have a cord chain or string wound thereon with a knob or tag outside to
grasp the end thereof. Upon pulling this cord or the like same will be unwound
off the pulley and thereby revolve said roller as is well understood.
A second and similar cord or the like would be wound in the opposite direction
on a similar pulley on the roller of the second blind.
The winding of the first blind from one roller on to the other will cause a spring
or springs or equivalent to be wound up or strained-for instance a spring coiled
within one of the rollers aforesaid or a spring arranged outside and clear of said
roller one end of which is fixed to the drum and the other end having a cord
or similar connection therefrom wound round a drum or pulley on said roller so
that the rotation of said roller will cause the straining of said spring which strain
upon release of the aforesaid releasing device will cause the opposite revolution
of said roller or same may be spring actuated or driven in any other suitable
manner.
A second and similar separate arrangement of spring or springs or equivalent
will similarly act on the second and separate blind.
Independent means are provided for winding or straining more or less the spring
mechanism for each blind so as thus to increase or diminish the speed of travel of
same independently of one another. Thus the two separate blinds may be caused
to travel at different speeds i.e. the front one quicker than the back one or
vice versa.
Any suitable retarding device or regulating device such as a pneumatic cylinder
and piston may be arranged and combined in any suitable manner with each blind
separately and, either with or without such pneumatic retarding device, I find it
advantageous to use the following regulating device by which I am enabled to give
a differing speed of travel to the first blind at one part of its travel to the speed of
the other part of its travel and a similar second and separate regulating device
applied to the second blind enables me to give a differing speed of travel to the
second blind also when the exposure is being given.
For this purpose on the second roller of the first blind I arrange and mount a
small friction wheel or drum the periphery of which comes in contact with a second
and larger triction drum or wheel mounted on a fixed stud with a crank arın
extending through the side of the camera case or other means to move round this

page_text: dummy wheel or drum and also serve as an index pointer or indicator to show
position of the dummy drum.
This second and large dummy wheel or frictional drum (acting as a brake where
it comes in contact with the aforesaid friction wheel on the axis of the blind roller)
is mutilated i.e. has a segment or other part cut away or recessed out of the
periphery so as to destroy part of said periphery or circumference.
When this recessed or mutilated part of the brake drum coincides with the
aforesaid small friction drum the latter can then revolve unrestrained and when the
circumference of said brake drum bears against said small friction drum thereby
considerable resistance is offered to the latter.
Now by means of the aforesaid crank arm or other suitable means this large
brake drum can be moved around so that the mutilated part lies furthest away from
the small friction wheel or at any intermediate position desired. Then when the
shutter is released this small friction wheel on one of the blind rollers is thereby
revolved and in its turn bears against and revolves this said large brake drum until
the aforesaid mutilated part comes round and coincides with the periphery of the
small friction drum and thereupon the latter finishes its revolution or revolutions
unrestrained.
A corresponding separate regulating device or arrangement is independently and
similarly applied to the second blind.
Thus for taking photographs of landscapes where it is desired to give to the
fore-ground a longer exposure than that to be given to the sky this friction brake
can be set so as to cause a slower rate of travel to the blind shutter at the first part
of the exposure when the fore-ground is being taken and then a much more rapid
travel to the shutter when the sky is being taken-this being a great desideratum in
photography with a focal plane shutter.
To cause my shutter to act as a focal plane shutter of adjustable aperture all
that need be done is to wind up the first shutter to its full extent and thereafter to
wind up the second shutter to any desired degree less than its full extent-for
instance so that the top edge of the aperture of the second blind remains inch or
inch or other desired distance from the bottom edge of the aperture of the first
blind. Thus on these two blinds being simultaneously released they will travel
down together keeping their exact relative distance apart (as set) thus acting as a
focal plane shutter and one which can be adjusted to a different size of aperture
at each successive operation if desired by means of the setting or winding
mechanism.
Blind shutters constructed in accordance with the foregoing thus afford
facilities which (so far as I am aware) are not approached or even contemplated
with any other one shutter in the market.
Dated this 18th day of August 1893.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and in connection with Photographic Shutters of
the Character known as "Blind Shutters."
I, HENRY COOK M.D. F.R.C.P. Lond. J.P. etc., etc., Priors Mesne, Lydney,
Gloucester, Surgeon General retired, Her Majesty's Indian Army, 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 shutters for photographic purposes of the character

page_text: §
roner Diu sautters and my present
invention is designed to produce a shutter which will (inter alia) afford the
following advantages combined in one shutter viz. :--
(1) A safety blind shutter.
(2) A focal plane shutter.
(3) Capable of regulating the duration of exposure.
(4) Capable of regulating the size of the exposure aperture at each successive
exposure without taking to pieces or disturbing the camera or removing or
disturbing the sensitive plate or surface.
(5) Capable of giving varying speed of travel during exposure so that more
exposure can be given to one part of the sensitive surface than to the other.
(6) Capable of working close up to the sensitive surface.
(7) A double blind shutter occupying very little space.
Besides affording (inter alia) the combined advantages and facilities above set
forth the whole of the parts are simple and economical in construction and not
easily liable to get out of order.
My present invention is as follows:-
In a suitable frame or support I arrange and mount two separate and distinct
roller blinds which for the sake of clearness I will term the first and second blind
and these two blinds are advantageously mounted and arranged to travel in parallel
planes or thereabouts and in close proximity to one another.
The first blind is mounted on two rollers or equivalents so as to be capable of
being wound off one roller on to the other to set the shutter ready for giving an
exposure and thereby winding or straining a spring or springs the reaction of which
will wind back the blind when same is released and the exposure given through
an aperture or opening in the said blind thus passing across the path of the lens-
all of which per se is old and well-known in the numerous existing forms of blind
shutters.
:
A second and similar blind is mounted and arranged in close proximity to the
first blind but entirely separate therefrom being separately actuated by separate
setting device separate spring or springs acting on separate rollers but simul-
taneously released with the said first blind and each of these two separate blinds
may in setting be caused to travel either the maximum distance or less and can be
set and held in any desired position-thus the first blind can be first caused to
travel its maximum distance and there set ready for the release-the second blind
meantime acting as a safety blind while setting the first then the second blind can
be caused to travel its maximum distance or any less distance and is then caught
and held by the releasing device (which simultaneously releases both blinds as
hereinafter described) the first blind now acting as a safety for the second blind
while setting the latter.
The two blinds may be mounted in opposite directions on their respective
rollers so that by each winding outwardly the part of each blind between the
rollers can be brought very close to one another and if desired travel in guideways
or recesses along their edges so as to prevent the one blind' catching or interfering
with the other.
For the purpose of simultaneously releasing both blinds I arrange and mount a
ratchet wheel or equivalent on the axle or one end of one roller of the first blind
and a corresponding ratchet wheel on one end of one roller of the second blind and
these ratchet wheels will be (or may be) right and left-handed. A releasing rod
or lever extends to the exterior of the camera case or so as to be capable of being
grasped or touched by the operator and has two pawls extending therefrom which
pawls are respectively kept pressed into gear with the said ratchet teeth by
means of spring or equivalent normally pressing said releasing rod in such manner
as to keep the said pawls thereof continually in gear with the said ratchet wheels
respectively.
Thus when either blind is being set or wound ready for giving an exposure the
teeth of the ratchet wheel being revolved will run past the pawl while immediately

page_text: the setting or winding gear is released the pawl will engage in the next adjacent
tooth on said ratchet wheel and similarly with the other blind while on pressing or
moving the aforesaid releasing lever the two pawls will be thereby simultaneously
moved clear of the two ratchet wheels and thereby the two blinds will be
simultaneously released.
Any other equivalent or suitable simultaneous releasing device may be adapted
or used in place of the foregoing if desired.
Any suitable means may be used for winding or setting each blind separately-
for instance a pulley on the end of the roller opposite the aforesaid ratchet wheel
may have a cord chain or string wound thereon with a knob or tag outside to grasp
the end thereof. Upon pulling this cord or the like same will be unwound off the
pulley and thereby revolve said roller as is well understood.
A second and similar cord or the like would be wound in the opposite direction
on a similar pulley on the roller of the second blind.
The winding of the first blind from one roller on to the other will cause a spring
or springs or equivalent to be wound up or strained-for instance a spring coiled
within one of the rollers aforesaid or a spring arranged outside and clear of said
roller one end of which is fixed to the drum and the other end having a cord or
similar connection therefrom wound round a drum or pulley on said roller so that
the rotation of said roller will cause the straining of said spring which strain
upon release of the aforesaid releasing device will cause the opposite revolution
of said roller or same may be spring actuated or driven in any other suitable
manner.
A second and similar separate arrangement of spring or springs or equivalent
wil similarly act on the second and separate blind.
Independent means are provided for winding or straining more or less the spring
mechanism for each blind so as thus to increase or diminish the speed of travel of
same independently of oue another. Thus the two separate blinds may be caused
to travel at different speeds i.e. the front one quicker than the back one or
vice versa.
Any suitable retarding device or regulating device such as a pneumatic cylinder
and piston may be arranged and combined in any suitable manner with each blind
separately-and, either with or without such pneumatic retarding device, I find it
advantageous to use the following regulating device by which I am enabled to give
a differing speed of travel to the first blind at one part of its travel to the speed
of the other part of its travel and a similar second and separate regulating device
applied to the second blind enables me to give a differing speed of travel to the
second blind also when the exposure is being given.
For this purpose on the second roller of the first blind I arrange and mount a small
friction wheel or drum the periphery of which comes in contact with a second and
larger friction drum or wheel mounted on a fixed stud with a crank arm extending
through the side of the camera case or other means to move round this dummy
wheel or drum and also serve as an index pointer or indicator to show position of
the dummy drum.
This second and large dummy wheel or frictional drum (acting as a brake where
it comes in contact with the aforesaid friction wheel on the axis of the blind roller)
is mutilated i.e. has a segment or other part cut away or recessed out of the periphery
so as to destroy part of said periphery or circumference.
When this recessed or mutilated part of the brake drum coincides with the
aforesaid small friction drum the latter can then revolve unrestrained and when the
circumference of said brake drum bears against said small friction drum thereby
considerable resistance is offered to the latter.
Now by means of the aforesaid crank arm or other suitable means this large
brake drum can be moved around so that the mutilated part lies furthest away
from the small friction wheel or at any intermediate position desired. Then when
the shutter is released this small friction wheel on one of the blind rollers is thereby
revolved and in its turn bears against and revolves this said large brake drum until

page_text: the aforesaid mutilated part comes round and coincides with the periphery of the
small friction drum and thereupon the latter finishes its revolution or revolutions
unrestrained.
A corresponding separate regulating device or arrangement is independently and
similarly applied to the second blind.
Thus for taking photographs of landscapes where it is desired to give to the
foreground a longer exposure than that to be given to the sky this friction brake
can be set so as to cause a slower rate of travel to the blind shutter at the first
part of the exposure when the fore-ground is being taken and then a much more
rapid travel to the shutter when the sky is being taken-this being a great
desideratum in photography with a focal plane shutter.
To cause my shutter to act as a focal plane shutter of adjustable aperture all
that need be done is to wind up the first shutter to its full extent and thereafter to
wind up the second shutter to any desired degree less than its full extent-for
instance so that the top edge of the aperture of the second blind remains inch or
inch or other desired distance from the bottom edge of the aperture of the first
blind. Thus on these two blinds being simultaneously released they will travel
down together keeping their exact relative distance apart (as set) thus acting as a
focal plane shutter and one which can be adjusted to a different size of aperture
at each successive operation if desired by means of the setting or winding
mechanism.
Blind shutters constructed in accordance with the foregoing thus afford facilities
which (so far as I am aware) are not approached or even contemplated with any
other one shutter in the market.
And in order that my invention may be easily understood and readily carried
into practice I will proceed to further describe same with reference to the drawings
hereunto annexed :—
Fig. 1 is a plan of the case containing the double blind shutter according to my
present invention.
Fig. 2 is a front view of Fig. 1 having part of the casing removed so as to show
the interior mechanism controlling said double blind shutters.
Fig. 3 is an end view (with the casing removed) of Figs. 1 and 2 looking in the
direction of the arrow 2.
Fig. 4 is a view of the opposite end of Figs. 1 and 2 with the casing removed
i.e. looking in the opposite direction to the arrow z.
Fig. 5 is a diagram showing the double blinds fully wound previous to giving an
exposure.
Fig. 6 is also a diagram showing relative position of the double blinds midway
in their travel (that is at mid-exposure)" when the aperture in each blind
coincide and travel together so that the exposure is given through the maximum
size of slot in said blind.
Fig. 7 is a front elevation of the apparatus (the opposite side to Fig. 2) showing
the double blinds set in such a manner that the upper edge of the aperture in one
blind falls about inch above the lower edge of the aperture in the other blind and
thus travelling together the exposure is given in this case through a narrowed slit
of only about inch in height.
Fig. 8 is an exterior end view looking in the direction of the arrow y.
Fig. 9 is an exterior view of the other end of Fig. 7 i.e. looking in the opposite
direction to the arrow y.
A is the one blind wound upon the roller A¹ at the top and A2 at the bottom.
B is a second separate and independent blind wound upon the second and separate
roller B at the top and B2 at the bottom.
Each such blind A and B respectively having a slot or aperture therein of a size
such as shown in Fig. 6 or of any other desired and suitable size respectively.

page_text: a is a cord or equivalent wound upon the drum or pulley a' which latter is firmly
fixed on the axis of the roller A' so that on pulling the string a (by means of the
button or catch a² thereon) thereby the said string a is unwound off the drum a¹
which is thereby revolved and in its turn revolves the top roller A¹ which in its
turn again winds the blind A thereonto off the bottom roller A².
Similarly the second and separate string (having a button or catch 62 thereon)
has one end thereof fixed to a similar drum to a fixed on the axis of the second
blind roller B and on unwinding this said string 6 off this said drum thereby the
top roller B is caused to revolve so as to wind thereon the second blind B off its
bottom roller B².
It will thus be seen that the winding of each blind A and B is respectively
controlled independently of the other.
Instead of these strings a and b-any other equivalent or suitable means may he
adapted to independently wind each blind A and B for instance the axis of each
roller A and B respectively may extend through the casing and a separate handle-
or knob on each will enable the operator to wind up each blind separately a pointer
or index or other suitable arrangement being provided to show how far each blind'
has been wound and therefore the size of the slit or opening formed by the two.
blinds through which the exposure will be given.
Upon winding the blind A as before described the bottom roller A³ has fixed on.
the axis thereof a drum a³ to which is attached one end of a string cord chain or
equivalent c which by the rotation of said drum a³ is wound thereon while the other
end of this cord etc. c is attached to a coiled spring c¹ which it thereby extends and
thus the reaction of this spring has a tendency to revolve back again the drum a
and thereby re-winds the blind A upon its roller A³ immediately said blind A is.
released from the catch or holding mechanism which retains same when wound.
INDEPENDENT CONTROL OF EACH BLIND.
In order to adjust the tension of this spring and thereby vary the speed of travel.
imparted to the blind A upon the re-winding of same off A¹ on to A' the other
end of this spring c¹ is carried by a flexible cord or equivalent such as which
latter extends through the casing and terminates in an eye or loop c³ which can be
grasped and the cord etc. c² pulled out a suitable distance and the said loop c³ is.
then placed over a stud or post et a number of which may be provided at varying
distances see Fig. 9 and thus varying degrees of strength are imparted to the
spring which thereby imparts varying speed of travel to the blind A.
In a similar manner a second and separate drum bis fixed on the axis of the
roller B2 and a cord etc. d wound upon said drum 63 is attached to one end of a.
second spring d' (separate and independent of c¹) to the other end of which latter
is attached the setting cord d' having a loop d³ on the exterior of the casing by
which means said second string can be pulled out and set to any desired degree of
tension by placing the loop d³ over one or other of the studs d see Figs. and 7.
Thus while the one blind A can be caused to travel at its normal speed that is
without altering the tension of the spring e' the spring controlling the other blind B.
can be extended by means of the loop d and thereby the blind B caused to travel
at a greater speed than the blind A or vice versa.
SIMULTANEOUS RELEASING DEVICE.
The simultaneous releasing apparatus is shown at the right hand end of Fig. 2.
and in Fig. 4.
e is a ratchet wheel fixed on the axis of the roller A' and e' is another ratchet.
wheel fixed on the axis of the roller B₁ with the teeth thereof arranged in the
manner shown in Fig. 4.
fis a pawl engaging with the teeth on the wheel e and is another pawl
engaging with the teeth in the ratchet wheel e¹.

page_text: Both these pawls fand f' are mounted on the same vertical rod g the lower end
of each passes through guides g' and is combined with a spring g² so as to normally
keep said vertical bar 9 pressed upwards and thereby the pawls f and f¹ are
normally kept pressed up into the teeth of the ratchet wheels e and e'. The upper
end of 9 passes through an aperture in the case which thus acts as a guide or
bearing for same and terminates in the knob or presser button h.
Or instead of this releasing knob being actuated by the finger of the operator
direct any well-known pneumatic or other suitable releasing device may be used or
adopted to operate this rod 9 so as to press same downwards against the spring g
It will thus be seen that by pushing down the rod g the pawls fand fare
simultaneously moved out of gear with the teeth of the ratchet wheels e and et
respectively and thereby the rollers A' and B₁ are simultaneously released
consequently the blinds A & B are thus released at identically the same moment.
adopted to operate this rod g so as to press same downwards against the spring g².
It will thus be seen that by pushing down the rod g the pawls fand fare
simultaneously moved out of gear with the teeth of the ratchet wheels e and e¹
respectively and thereby the rollers A¹ and B₁ are simultaneously released
consequently the blinds A & B are thus released at identically the same moment.
SPEED REGULATING DEVICE.
To give a differing speed of travel to the blind A at one part of its travel to the
speed of the other part of its travel-on the left-hand end of the roller A' I mount
a drum i which being fixed to the axis of A² is caused to revolve when the latter
revolves.
Against this drum i bears the second drumj (which is mutilated at j¹) mounted
on the axis. This axis extends through the casing and upon the outside of the
case carries the pointer or index arm see Figs. 3 and 9 by means of which
latter the mutilated wheel ; can be moved round to any desired position-a dial or
index being provided on the exterior of the case for this purpose so that while the
blind A is being wound off roller A¹ on to roller A' the brake wheel i will bear
against the periphery of j and move same round until the cut out part j' comes
opposite whereupon the latter can run free and consequently the brake being
taken off the roller A' the latter moves quicker and thereby a differing speed is
given at one part of the travel to the speed of the other part of the travel of
blind A.
By moving the wheel; (by means of the pointer ³) so that the cut out part in
coincides with i thereby can remove any brake or checking action on the
roller A'.
A similar but separate regulating device or brake may be similarly applied to
the second blind although not shown in the drawings.
орст
When it is desired to give an exposure with the largest aperture possible each
cord a and b is pulled out to the index line marked "full" in Fig. 1 and thereby
each blind A and B is fully wound up.
The tension of each spring c¹ and d¹ is made to coincide and the brake or
retarding device ij is thrown out of gear as before explained. Upon pressing the
button and simultaneously releasing both blinds A and B as before explained
the two blinds A and B will now travel at exactly the same rate of speed and the
aperture in each blind coinciding with the other will travel together and the
exposure be given through the widest possible aperture.
To diminish the size of the aperture-one of the blinds say A is wound up by
pulling the cord a out to the index line marked "full" while the other blind is
only partially wound that is the cord 6 is only pulled out to the line marked 2, 5, 10
or 20 which indicate the number of times the rapidity of the shutter is increased
(i.e. by diminishing the size of the aperture) thus if pulled up to the point
marked "2" the slot is diminished to one-half and the speed of exposure is
therefore double; if to "o" the aperture is diminished one-fifth and the speed
multiplied by five and so on.

page_text: To make a time exposure both cords are pulled up to the line marked "Time
when the full aperture of both blinds is secured and when the desired length of
exposure has been made both are released together by pressing the button h.
To vary the size of aperture during an exposure-the spring of one blind is
extended so that the speed of travel of one blind is greater than that of the other
and both blinds being simultaneously released consequently one blind will overtake
the other and thus either increase or diminish (as the case may be) the size of the
aperture during the exposure (or any particular part thereof) so that the sky may
be exposed less than the foreground of the picture.
It will thus be seen that great variety is obtained in the control of the shutter
which can be readily altered to suit the conditions or requirements of each.
succeeding exposure.
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In photographic shutters of the character described-the combination of two
separate and independently wound roller blinds both travelling in the same
direction when giving an exposure with a separate adjustable spring or motor to
separately actuate each such blind respectively.
2. In photographic shutters of the character described-the combination of two
separate and independently wound roller blinds each having an exposure opening
therein travelling in the same direction when giving an exposure and each capable
of being set and retained in any desired position by a releasing device common to
both.
3. In photographic shutters of the character described-the combination of two.
separate and independently wound roller blinds with means to independently
control the speed of travel in the same direction of each blind respectively and
means to simultaneously release both said blinds to give the exposure.
4. In photographic shutters of the character described - the combination of two.
separate and independently wound roller blinds with means to independently
control the speed of travel in the same direction of each said blind and means also
to vary the speed of travel of one or both said blinds during an exposure.
5. In photographic shutters of the character described-the combination of two
separate roller blinds with means to independently control the speed of travel in
the same direction of each said blind means to simultaneously release both said
blinds and means to vary during an exposure the speed of one or both said blinds.
6. In photographic shutters of the character described-the combination with
two separate and independently wound roller blinds of means to independently
control the speed of travel of each blind respectively substantially as and for the
purposes set forth.
7. In photographic shutters-the arrangement and combination of two separate
and independently wound roller blinds released and operating together to give the
exposure but each mounted actuated set and controlled as to speed independently
of one another substantially in the manner and for the purposes hereinbefore set
forth.
8. In photographic shutters-the combination of two separate and independently
controlled roller blinds with means to independently wind each blind as far as
desired and there retain same and means to simultaneously release same to give
the exposure substantially as and for the purposes set forth.
9. In photographic shutters-the combination with two separate roller blind
of a ratchet wheel such as e carried on the axis of one of the rollers of one said
blind a second and separate ratchet wheel such as e¹ carried on the axis of one of
the rollers of the other said blind and two pawls such as fand f' carried on the-
same slide bar or releasing device such as g substantially in the manner and for
the purposes herein before described and illustrated in the drawings hereunto-
annexed.

page_text: 10. In photographic cameras- the combination with two separate roller blinds
of independent rollers upon which to wind such blinds means such as the cords a
and b to wind each said blind either fully or partially upon its respective roller
independent means such as the separate ratchet wheels e and e¹ of retaining each
said roller at any point whether said blind be fully or only partially wound thereon
and a simultaneous releasing device such as the two pawls ffi carried on the
movable bar g all arranged and acting substantially in the manner and for the
purposes herein before described and illustrated in the drawings hereunto annexed.
11. The improved photographic shutter arranged combined and acting substan-
tially in the manner and for the purposes hereinbefore set forth and illustrated in
the drawings hereunto annexed.
Dated this 18th day of May 1894.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.